text
string | predicted_class
string | confidence
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|---|---|---|
Incongruent with the hypothesis, we did not find the GMV of the ventral striatum correlating with the IAT score. The ventral striatum is a critical region related to the addiction, and usually presents abnormal activation in individuals with addiction (26, 27). In our study, we focused on adolescent online game players but not only the IGD individuals, which might be a possible explanation to the negative result of ventral striatum. However, this negative result should be verified in the future study with large sample size.
|
study
| 100.0 |
Unexpectedly, the preCG, postCG, and the pMCC involved in the sensorimotor process showed negative correlations with the IAT score. The preCG played a major role in the motor planning and conducting (47). Adolescence is a critical period of neural development, and is prone to be affected by the environmental factors. Previous studies demonstrated that the alcohol and drug use might change the GMV in the developing brain of adolescents (48). A study showed longer use of the methamphetamine was associated with the GMV reduction in the preCG (49). In our study, the GMV of preCG was lower in the high IAT score subgroup than that in the low IAT score subgroup. Considering prevention and suppression of the action is conceptually associated with the primary motor cortex (50), the decreased GMV of preCG might be related to the IGD tendency. The postCG consists of the primary sensory cortex and is involved in integrating sensory information (24). The negative correlation between the GMV of the postCG and the IAT score means the lower GMV of this region in individuals with higher IAT score. Abnormal function connectivity of the postCG was found in adolescents with IGD (51). The decreased GMV and cortical thickness of the postCG were also revealed, respectively, in heroin users (52) and adolescents with online gaming addiction (53). The impaired postCG may lead to abnormality in receiving, processing, and integrating body-relevant signals and may fail to guide ongoing behavior related to arousal, attention, stress, reward, and conditioning, and finally associated with the addiction (54). In this study, negative structural correlations to the IAT score were also found in the left pMCC. The pMCC exhibits extensive functional connectivity with brain regions involved in the sensorimotor network (55, 56) and has important role in processing sensorimotor integration and motor control (57). The sensorimotor areas not only control the basic aspects of movement but can also shape human behavior (58). The functional properties of sensorimotor network may be relevant for automatized/compulsive behaviors in addiction (59). Sensorimotor cortex impairments were also reported in individuals with cocaine addiction (60, 61) and alcohol ingestion (62). Taken together, the reduction of the GMVs within the preCG, postCG, and the pMCC might have association with the abnormalities of the sensorimotor network, and further associated with the IGD tendency.
|
study
| 99.94 |
In the present study, the negative correlations between the IAT score and the GMVs of the right preCG/postCG, the left IPL, and the right precuneus disappeared after controlling for the effect of the total time of playing online game. The preCG/postCG was involved in sensorimotor process (63); the IPL and the right precuneus were closely related to the visual and intentional processing (64–66). Gaming process requires players to pay full attention to the tiny change in the screen for a long time then injures their visual ability (65), which might have a relationship with the GMV reduction in the visual attention-related regions. Previous studies demonstrated decreased GMV of precuneus (8) and decreased cortical thickness of the IPL (53) in the individuals with online game addiction. Our results indicated that the GMV reduction in some brain regions related to the visual attention and sensorimotor process was influenced by the total time of playing online game, namely had a cumulative effect of playing online game.
|
study
| 100.0 |
Several limitations should be noted in our study. First, although some correlations were revealed between the brain GMV and IAT score, the causality cannot be clarified in this correlation analysis. The observed lower GMV in the adolescents with higher IAT score may be a result of excessive online game playing or a preexisting condition which is sensitive to IGD. Second, the IAT is a subjective questionnaire and more objective methods for evaluating the tendency to IGD are needed. Third, the total time of playing online games was just a probable measure and might be not accurate enough. Fourth, we could not rule out the effect of game genre on the results, which should be considered in the future study. Finally, only male adolescents were recruited in our study. Therefore, the present findings are restricted to male adolescent online game players.
|
study
| 100.0 |
In this study, the structural correlation to the IGD tendency was investigated in a group of adolescent online game players. The GMV of brain regions related to the sensorimotor process and cognitive control were found to be associated with the IAT score. The lower GMV of the regions related to sensorimotor process and cognitive control might attribute to the high IGD tendency, which might lead to new targets for preventing and treating the IGD in adolescents.
|
study
| 100.0 |
Ocular involvement in patients with candidemia is classically reported as a significant complication with devastating consequences, a high rate of vision loss, and a potentially fulminant course [1–5]. Several guidelines consistently recommend routine ophthalmoscopy in all candidemic patients [6–9]. That is because when eye involvement is detected, antifungal therapy should include azoles or liposomal amphotericin B, occasionally combined with vitrectomy and/or intraocular antifungal drugs, and the duration of treatment should be extended for 4–6 weeks [6–9].
|
review
| 99.9 |
Nevertheless, recent series showed a low frequency of symptomatic ocular disease and a favorable clinical outcome in almost all patients with Candida eye involvement who received systemic antifungal treatment . Moreover, the recommendation to perform systematic ophthalmoscopy is based not on the findings of a randomized controlled trial, but rather on the results of old, small-scale studies that do not clearly state clinical benefits [1–5].
|
review
| 99.9 |
The findings reported here are from a post hoc sub-analysis of the Population Study on Candidemia (CANDIPOP), a prospective, multicenter, population-based candidemia surveillance program implemented in 29 hospitals in Spain. The inclusion criteria, study population, main definitions, microbiological studies, and outcomes have been extensively described elsewhere . Briefly, during the study period local laboratories daily identified patients and reported them to study coordinators, who collected data using a standardized case report form. Data included demographic and clinical characteristics, risk factors for candidemia, antifungal management and source control. Thirty-day follow-up outcome was recorded for each patient. Given the observational nature of the study, patients were managed according to routine clinical care.
|
study
| 100.0 |
Severity of the infection and Pitt bacteremia score were recorded on the day of blood culture sampling . Proven catheter-related candidemia was defined according to current guidelines , whereas secondary candidemias required the microbiological documentation of the same Candida species at the origin of infection . When there was no apparent infection at another site, candidemia was classified as primary. An episode of candidemia was defined as persistent when patients had positive follow-up blood cultures performed according to IDSA guidelines .
|
study
| 99.9 |
The local institutional review boards of each participating center approved this study, and written informed consent was obtained from each patient before enrollment (IRB of the coordinating center for this study: Comité Ético de Investigación Clínica, Hospital General Universitario Gregorio Marañón).
|
other
| 99.94 |
Systematic dilated ophthalmoscopy was recommended at baseline for all patients included in the study, although only pathological findings suggestive of Candida ocular involvement were recorded in the general CANDIPOP database. To overcome this limitation, we asked the 29 participating hospitals to re-check whether ophthalmoscopy had been performed in patients aged >16 years who had experienced an episode of candidemia. Eleven hospitals complied with our request.
|
study
| 100.0 |
The study coordinators were invited to retrospectively review the results of all ophthalmological examinations in order to categorize ocular involvement as proven, probable, or possible Candida chorioretinitis or endophthalmitis . To be considered proven, ocular candidiasis had to be diagnosed based on the presence of an ocular lesion and on isolation of the microorganism from the vitreous humor by culture or histopathology-based identification. Probable Candida endophthalmitis consisted of vitritis or fluffy lesions with extension into the vitreous humor. Probable Candida chorioretinitis included deep focal white infiltrates in the retina, hemorrhages, Roth spots, or cotton wool spots. In patients with diabetes, hypertension, or concomitant bacteremia, ocular involvement was classified as possible based on previous criteria . Injection of intravitreal antifungal agents or intravitreal corticosteroids was recorded, as was the need for vitrectomy.
|
study
| 99.94 |
Categorical variables are presented as absolute numbers and their relative frequencies. Quantitative variables are presented as means and standard deviation (SD) if normally distributed and as median and interquartile range (IQR) if non-normally distributed. We compared categorical variables between groups using the Pearson chi-square and Fisher exact tests; we compared continuous variables using the Mann-Whitney test or a two-tailed t test.
|
study
| 99.7 |
One of our main objectives was to analyze the impact of systematic ophthalmoscopy on the outcome of patients with candidemia. Since very early mortality is generally associated with the impossibility to perform an ophthalmoscopy, patients who died within 3 days after withdrawal of blood cultures (12 patients) were excluded from mortality analysis to rule out potential bias.
|
study
| 99.94 |
Probable Candida endophthalmitis occurred in 2 patients, whereas probable and possible chorioretinitis were present in 8 and 3 cases, respectively. Interestingly, all patients but 1 (a patient with probable bilateral chorioretinitis who had low visual acuity) were asymptomatic when the diagnosis of ocular candidiasis was established. Accordingly, symptomatic ocular disease due to Candida occurred in 0.27% of the whole candidemic population (1 out of 365 patients) and in 7.6% of the 13 patients with ocular involvement (1 out of 13 patients).
|
study
| 99.9 |
Overall, 102/365 patients (27.9%) died within 30 days of the episode; 12 of these patients died within 3 days of blood sample collection and were, therefore, excluded from the mortality analysis. Univariate analysis of risk factors for 30-day mortality in the 90 remaining patients showed that the factors associated with poor outcome were admission to the ICU, previous renal disease, HIV infection, previous corticosteroid treatment, primary source of infection, septic shock, higher Pitt score, and need for hemodialysis as a complication of candidemia. The factors associated with a better outcome were admission to a surgical ward, receipt of azoles, and ophthalmoscopy.
|
study
| 99.94 |
However, when a multivariate analysis was performed, the independent risk factors for mortality (Table 1) were septic shock at presentation of candidemia, primary candidemia, and a high Pitt score. Performance of ophthalmoscopy did not remain an independent protective factor for 30-day mortality (OR, 0.59; 95% CI, 0.34–1.05; p = 0.08).
|
study
| 99.94 |
The outcome of ocular candidiasis is summarized in Table 2. Overall, information on the evolution of ocular candidiasis was available in 7/13 patients (53.8%), since 5 died and fundoscopy follow-up was not available in the remaining patient. Antifungal treatment was considered successful in 6/7 patients. None of the patients with Candida eye involvement needed intravitreal injection of antifungals or surgery.
|
study
| 74.0 |
*Patient number 2 was a renal transplant recipient who developed C. albicans septic shock after aortic aneurysm repair. Fungal infection was complicated with acute renal failure needing continuous renal replacement therapy andwith ocular candidiasis. Micafungin was administered because of stable levels with hemofiltration, lack of drug-drug interaction and because of its activity on Candida biofilm (the patient had a central venous catheter that could not be withdrawn). The outcome of ocular candidiasis was good.
|
clinical case
| 99.94 |
As shown in Table 3, patients with ocular candidiasis were significantly younger, had more commonly a history of renal disease [53.8% (7/13) vs 26.5% (41/155), p = 0.05] and a higher median Pitt score at presentation of the candidemia [3 vs 1 p = 0.01]. Fungemia causing ocular candidiasis was more frequently persistent [61.5% (8/13) vs 26.5% (41/155), p = 0.02], was produced by C. albicans [76.9% (10/13) vs 47.1% (73/155), p = 0.04], spread to other organs [38.5% (5/13) vs 9.7% (15/155), p = 0.01], and conditioned more need for hemodialysis [30.8% (4/13) vs 1.9% (3/155), p = 0.001]. As for antifungal treatment, patients with ocular candidiasis more commonly received an adequate antifungal therapy within the first 48 hours [100 (13/13) vs 67.7% (105/155), p = 0.01], and had a longer length of antifungal therapy (mean days 22.2 vs 39.6, p = 0.047). No further differences were found between the groups regarding demographics, risk factors, and management of candidemia. In the multivariate analysis (Table 4), the independent risk conditions for eye involvement were need for hemodialysis after candidemia (OR, 19.4; 95% CI, 1.7–218.4) and involvement of organs other than the eye (OR, 5.4; 95% CI, 1.1–25.7).
|
study
| 99.94 |
Our study shows that, despite the recommendation by several guidelines that systematic ophthalmoscopy should be performed in all patients with candidemia [6–9], as many as 50% of patients never actually underwent ophthalmoscopy. Furthermore, the yield of this examination is low, and ocular infection is uncommon and mostly asymptomatic. Our data also show no independent impact of ophthalmoscopy on the outcome of candidemic patients.
|
study
| 99.94 |
The incidence of ocular candidiasis in patients with candidemia varies from 50% in older studies [14–17] to less than 5% in more recent ones [18, 19]. In the present report, the overall incidence of ocular candidiasis was 7.7%, which is consistent with that observed by Shah et al , who found a 7.9% frequency of chorioretinitis, with no cases of endophthalmitis. The widespread use of early antifungal therapy and improvements in diagnosis may explain the lower incidence of ocular candidiasis observed in recent years [18, 19, 21].
|
study
| 99.9 |
Nevertheless, recent guidelines recommend performing ophthalmoscopy in all candidemic patients [6–9], stating that “missing and not appropriately treating Candida endophthalmitis could have great consequences for the patients” . However, the quality of the evidence supporting this recommendation is low, as it is based on the clinical judgment of the Expert Panel members.
|
review
| 99.9 |
This weakness in the recommendations provided by guidelines is reflected in the wide range of rates of ophthalmoscopy in candidemic patients (53% to 75%) reported in the medical literature [22, 23]. In the same sense, although all patients included in the CANDIPOP study were prospectively followed by infectious disease specialists, we found that in “real life”, ophthalmoscopy was performed in less than 50% of the study population. In our fully publicly funded health care system, this low percentage cannot be attributed to cost- or reimbursement-related factors.
|
study
| 100.0 |
As for clinical manifestations, we found only 1 patient with ocular symptoms, ie, an incidence of symptomatic disease of 0.27% in the whole candidemic population. Moreover, ocular candidiasis progressed favorably in all except 1 of our evaluable patients, who was asymptomatic and did not experience vision loss. These findings are consistent with those recently reported by Oude Lahof, who observed visual symptoms in only 3.3% of patients with ocular candidiasis and a favorable outcome in almost all evaluable cases . Older studies reporting ocular candidiasis as a "malignant complication" were performed in an era when medical management of candidemia differed substantially from contemporary care [1–5, 24–26]. Furthermore, a high proportion of patients included in such studies had a history of intravenous drug use that was not observed in our series.
|
study
| 99.94 |
Oude Lashof found a similar mortality rate between patients with and without ocular candidiasis (43.3% vs. 36.5%, p = 0.31). We also observed nonsignificant differences (p = 0.13), thus indicating that the presence of ocular abnormalities does not predict a poor outcome.
|
study
| 99.94 |
Similarly, although the populations undergoing or not undergoing ophthalmoscopy were likely not identical, we did not observe an impact of routine ophthalmoscopy on clinical outcome. Performance of the examination resulted in a change in antifungal therapy in only 5.6% of the 168 patients. On the contrary, ophthalmoscopy generates an increase in hospital costs ($400 per consultation), is uncomfortable for patients, and carries a small risk of acute angle-closure glaucoma .
|
study
| 95.0 |
Since ocular candidiasis progressed favorably in almost all patients and given the lack of data on the clinical impact of longer treatment schedules, we believe that the recommendation of systematic dilated ophthalmoscopy for all candidemic patients should be reassessed. An alternative could be a risk-based approach, in which the examination is limited to symptomatic patients, those who do not respond to treatment, or those more likely to acquire ocular candidiasis.
|
other
| 99.9 |
Regarding this aspect, our findings are consistent with those reported by other investigators [10, 15, 20, 28, 29], who found increased severity of the underlying conditions (cancer, need for hemodialysis after candidemia, and corticosteroids) and exposure to a more virulent infection (C. albicans, persistent fungemia, septic metastasis in other organs) as risk factors for ocular candidiasis.
|
study
| 99.94 |
Our study is subject to a series of limitations. First, the CANDIPOP study was not designed to analyze ocular candidiasis; however, we report the broadest experience to date on ophthalmoscopy in a large population of patients who were prospectively followed by an infectious disease specialist. Second, only 46% of the candidemic patients underwent ophthalmoscopy, with the result that we may have underestimated the involvement of ocular Candida infection; however, no clinical manifestations of ocular candidiasis were observed in the group of patients who did not undergo ophthalmoscopy. Finally, no patients with a history of drug addiction were included in the study.
|
study
| 99.94 |
In conclusion, we provide data from a large series of patients with candidemia showing that ophthalmological assessment is frequently omitted and that the rate of ocular candidiasis is relatively low (7.7%), anecdotally symptomatic, and usually associated with a good outcome. A prospective clinical trial evaluating the real benefits of routinely performed ocular assessment in all candidemic patients to limit the use of such a cumbersome, low-yield examination.
|
study
| 91.1 |
The World Alzheimer Report has estimated that there were 46.8 million people with dementia worldwide in 2015, and that this number will reach 131.5 million by 2050 (Prince et al., 2015). However, pharmacological treatments are relatively ineffective in halting the progression of dementia. The lack of pharmacological options (e.g., vaccines or disease-modifying agents) has shifted the focus of researchers toward non-pharmacological treatments for dementia, such as cognitive training, aerobic physical exercise, and music therapy (Gates and Sachdev, 2014; Groot et al., 2016; Zhang et al., 2017).
|
review
| 99.9 |
Accumulating evidence suggests that non-pharmacological treatment may maintain or decrease the rate of cognitive decline in adults with mild cognitive impairment and early stage dementia (Rodakowski et al., 2015). Additionally, the protective effects of aerobic physical exercise against the development and/or progression of dementia have been well documented (Laurin et al., 2001; Abbott et al., 2004; Ravaglia et al., 2008; Erickson et al., 2011). Additional studies have suggested that physical exercise combined with cognitive training exerts a greater positive impact on cognitive function than physical exercise alone (Fabre et al., 2002; Oswald et al., 2006; Shatil, 2013; Satoh et al., 2014, 2017; Tabei et al., 2017). In older adults, physical ExM induces greater positive effects on visuospatial function and leads to more extensive neuroanatomical changes (Tabei et al., 2017) than exercise alone. In participants with mild-to-moderate dementia, ExM also exerts greater positive effects on cognitive function and activities of daily living than CS using portable game consoles or drills (e.g., easy calculations, mazes, and mistake-searching in pictures) (Satoh et al., 2017).
|
review
| 99.9 |
Despite recent advancements, few studies have focused on predicting outcomes following non-pharmacological treatment. Knowledge of such predictors may allow clinicians to modify factors that are likely to attenuate the effects of the intervention and to provide more targeted treatment (Hsu et al., 2017). Indeed, previous studies have demonstrated that clinical and demographic factors can influence the effect of non-pharmacological activities on cognition and on the behavioral and psychological symptoms of dementia (Särkämö et al., 2016; Hsu et al., 2017). However, the neuropsychological factors influencing non-pharmacological treatment, as well as the neural basis of its efficacy, remain unknown. Furthermore, no randomized controlled trials have compared such effects among different non-pharmacological treatment options.
|
review
| 99.8 |
Therefore, the purpose of the present study was to determine whether neuropsychological factors and regional brain atrophy [as measured via voxel-based morphometry (VBM)] can predict the rate of improvement following non-pharmacological treatment in participants with mild-to-moderate dementia and to compare the effects of different non-pharmacological interventions.
|
study
| 99.94 |
The present study included participants with mild-to-moderate dementia who had utilized nursing services, such as day care or group homes, in the towns of Mihama and Kiho, which are situated at the southern end of the Kii peninsula in Japan. This study received approval from the Kinan Hospital Research Ethics Committee, and conformed to the tenets of the Declaration of Helsinki, and all participants provided written informed consent. This study was registered at UMIN-CTR (UMIN000017066) on April 7, 2015. The present study included the same participants as a previous study, which investigated the effect of non-pharmacological interventions in participants with mild-to-moderate dementia (Satoh et al., 2017). The inclusion criteria were as follows: (a) current diagnosis of intractable dementia by neurological specialists, based on ICD-10 diagnostic criteria (World Health Organization, 1993); (b) score between 16 and 26 on the MMSE; (c) stable physical and psychological condition; and (d) preserved hearing, visual acuity, and physical movement sufficient to enable participation in the intervention. Participants were excluded if they met any of the following criteria: (a) presence of chronic debilitating disease, such as malignancy or infection; (b) presence of severe cardiac, respiratory, and/or orthopedic disabilities that would prevent participation in the intervention; (c) presence of paresis or coordination disturbances that would prevent participation in the intervention; and (d) diagnosis of treatable dementia.
|
study
| 99.94 |
Diagnoses of AD were performed in accordance with criteria established by the National Institute of Neurologic Disorders and Stroke/Alzheimer Disease and Related Disorders Association (McKhann et al., 1984). Diagnoses of VaD were performed in accordance with criteria established by the National Institute of Neurological Disorders and Stroke/Association Internationale pour la Recherche et l’Enseignement en Neurosciences (Román et al., 1993).
|
other
| 98.7 |
All participants received treatment with anti-dementia drugs, the most common of which was donepezil hydrochloride. Pharmacological and non-pharmacological activities performed in the nursing-care facilities remained unchanged during the 6-months intervention period. Neuropsychological assessments and brain MRI were performed at baseline and following the intervention.
|
clinical case
| 99.56 |
Participants participated in 40-min physical exercise sessions once per week over the 6-months intervention period (total number of sessions: 24). The exercise program was developed by the Yamaha Music Foundation based on a program used in our previous study, which investigated the efficacy of physical exercise combined with music in older adults with normal cognitive function (Satoh et al., 2014; Tabei et al., 2017). The program consisted of muscle training for the upper and lower extremities, hand clapping to music, breath and voice training, and singing. The exercise trainers were professional musicians who also held private licenses as physical trainers with the Yamaha Music Foundation.
|
study
| 99.94 |
Participants trained using a program called “Yawaraka Atama Juku (flexible thinking club)” developed by Nintendo Co., Ltd., using a portable game console (Nintendo DS LL, Kyoto, Japan) and performed drills consisting of easy calculations (Kawashima, 2003), mazes, and mistake-searching in pictures. Each session was 40 min long and were conducted once per week over the 6-months intervention period (total sessions: 24). Each session was moderated by nurses, certified care workers, or psychiatric social workers employed at the respective nursing facility.
|
other
| 98.6 |
The MMSE (Folstein et al., 1975) and RCPM (Raven, 1947) were used to quantify cognitive function. In addition to an overall score, the RCPM task measures performance time, which reflects the psychomotor speed of the participants. Memory was evaluated using the LM-I/-II subtests of the RBMT (Wilson et al., 1985), which requires immediate and delayed recall of a short story. The RBMT contains four stories of varying difficulty and different word counts. We used different stories for the pre- and post-test periods to avoid the influence of familiarity with story content.
|
study
| 100.0 |
Visuospatial ability was assessed using methods described by Strub and Black (2001). Participants were shown images of cubes and Necker cubes, and were then asked to draw a picture of each. Each drawing was scored by assigning one of four possible grades (0: poor, 1: fair, 2: good, and 3: excellent).
|
study
| 99.94 |
Frontal lobe function was assessed using two tasks: WF and Trail Making Test -A/-B (Partington and Leiter, 1949). The WF test consists of category and letter domains. In the categorical WF task, participants were asked to name as many animals as possible in 1 min. In the letter WF task, participants were asked to name as many objects as possible in 1 min beginning with each of the following four phonemes: ka, sa, ta, and te (Dohi et al., 1992). The average scores for these four phonemes were used for statistical analyses.
|
study
| 100.0 |
The Functional Independence Measure was used to evaluate functional performance regarding activities of daily living. The Functional Independence Measure consists of both motor and cognitive function domains. Motor function is assessed on thirteen items, including eating, dressing, evacuation, urination, and walking. Cognitive function is assessed on five items associated with understanding, expression, and memory. The maximum motor function, cognitive function, and overall Functional Independence Measure scores are 91, 35, and 126, respectively, with higher scores indicating better function. These neuropsychological assessments were administered to participants in both groups before and after the 6-month intervention period.
|
study
| 100.0 |
Participants were dichotomized into an IMP or no-IMP subgroup based on MMSE scores following the intervention. Participants with an increased MMSE score of 2 points or more were included in the IMP subgroup, while the remaining participants were included in the no-IMP subgroup. The cut-off of 2 points was determined based on the findings of previous studies, which had shown that changes in MMSE scores of 2 points are beyond the threshold of chance (Morris et al., 1993; Bowie et al., 1999; Ballard et al., 2003).
|
study
| 100.0 |
T1-weighted gradient echo MR images were obtained using a 1.5-T MR scanner (Echelon Oval, Hitachi Medical Corporation, Tokyo, Japan). Scan parameters were as follows: repetition time = Shortest (Automatic); echo time = 11 ms; flip angle = 90°; field of view = 230 mm × 230 mm; slice thickness = 4 mm; gapless; in-plane resolution = 0.45 mm × 0.45 mm. Scans were obtained both before and after the 6-month intervention period.
|
study
| 99.9 |
MRI data were analyzed using SPM12 (Wellcome Trust Centre for Neuroimaging, University College London, London, United Kingdom) implemented in MATLAB R2012a (MathWorks, Natick, MA, United States). In the pre-processing phase, images were set to match the anterior to posterior commissure line using an automated MATLAB script. The images were then visually inspected to check for possible scan issues such as field distortion and movement artifacts. Reoriented images were corrected for intensity inhomogeneity and segmented into GM, white matter, cerebrospinal fluid, and other tissues outside the brain using SPM12 tissue probability maps. The images were registered to the East Asian Brains International Consortium for Brain Mapping space template via affine regularization. We created a population-specific template using the SPM12 DARTEL template procedure to directly compare data between the IMP and no-IMP subgroups. We investigated group differences in GM volume, as well as the relationship between neuropsychological assessment results and GM at the whole-brain level. High-dimensional DARTEL was used to create non-linear, modulated-normalized GM and white matter images, which were smoothed using a Gaussian kernel of 8 mm FWHM (full-width at half-maximum). For whole-brain and multiple regression analyses, we assessed the statistical significance at a voxel threshold of p < 0.005 (uncorrected), within contiguous clusters of at least 20 voxels. We obtained both MNI and Talairach coordinates to detect the anatomical regions of the clusters. We used a transform from Matthew Brett1 to convert MNI coordinates to Talairach coordinates, and Talairach Client 2.4.3 (Lancaster et al., 2000) was used to identify the anatomical regions corresponding to Talairach coordinates.
|
study
| 100.0 |
Differences in demographic variables and neuropsychological assessment results between the IMP and no-IMP subgroups were analyzed using independent t-tests for continuous data, chi-square tests for dichotomous data, and Mann–Whitney U tests for non-parametric data. Differences of p < 0.05 were considered statistically significant. Statistical analyses were performed using IBM SPSS Statistics software version 20 (IBM Corp., Armonk, NY, United States).
|
study
| 99.94 |
Participants who participated in more than 75% of all sessions (more than 18) and completed the neuropsychological and MRI assessments before and after the intervention were included in the final analysis. Following exclusion of the remaining participants, the ExM and CS groups included 25 and 21 participants, respectively (ExM: AD = 21; VaD = 4; CS: AD = 18, VaD = 3) (Table 1). Prior to the intervention, there were no significant differences in sex ratio, dementia type, age, years of education, or MMSE scores between the ExM and CS groups. However, among participants in both ExM and CS groups, MMSE scores were significantly worse in the no-IMP subgroup than in the IMP subgroup at the 6-month follow-up (p < 0.001) (Table 1).
|
study
| 100.0 |
Participants in the no-IMP subgroup had significantly poorer baseline scores on the RCPM, LM-I section of the RBMT, and cognitive functional independence than those in the IMP subgroup (p = 0.04, 0.004, 0.033) (Table 2). Furthermore, baseline scores on the LM-I subtest were significantly worse in the no-IMP subgroup than the IMP subgroup (p = 0.025) of the ExM participants. In the CS group, baseline scores on the RCPM test and cognitive functional independence measure were significantly worse in the no-IMP subgroup than in the IMP subgroup (p = 0.034, 0.025, respectively) (Table 2).
|
study
| 100.0 |
Cube and Necker cube scores were used as covariates. Subtraction analysis revealed more extensive loss of GM in the left middle frontal gyrus in the no-IMP subgroup at baseline, relative to the IMP subgroup (Figures 1A,B and Table 3). Analysis of MMSE scores at the 6-month follow up revealed that changes in MMSE scores were positively correlated with volume in the left middle frontal gyrus (Figure 1C and Table 3). Subtraction analysis revealed more extensive GM loss in the anterior cingulate gyrus and left middle frontal gyrus in no-IMP participants in both the ExM (Figure 2A and Table 3) and CS (Figure 2B and Table 3) groups at baseline, respectively.
|
study
| 100.0 |
The present study aimed to determine whether neuropsychological factors and regional brain atrophy can predict the rate of IMP in participants with mild-to-moderate dementia following non-pharmacological intervention. Among ExM participants, the no-IMP subgroup exhibited poorer baseline performance on the LM-I subtest of the RBMT than participants in the IMP subgroup. Among CS participants, the no-IMP subgroup exhibited poorer baseline RCPM and cognitive functional independence measure scores than participants in the IMP subgroup. Such differences may be associated with differences in cognitive resources required to execute each intervention. Proper execution of the ExM protocol requires the participant to remember the exercise patterns from week to week, while proper execution of the CS protocol requires spatial and mathematical abilities that allow understanding of geometric designs and missing pieces, as well as expressive abilities and memory function to complete calculations, mazes, and search for mistakes in images. Although previous studies have indicated that exercise and ExM tasks enhance memory in participants with dementia (Radak et al., 2010; Intlekofer and Cotman, 2013; Satoh et al., 2017), our results suggest that execution of the intervention requires a certain amount of memory function reserve. These findings highlight the importance of early intervention, when cognitive function may be somewhat preserved (Dubois et al., 2016).
|
study
| 99.94 |
Voxel-based morphometry analysis revealed more extensive loss of GM in the anterior cingulate gyrus in no-IMP participants of the ExM group, and in the left middle frontal gyrus in the CS group at baseline relative to that observed in the IMP subgroup. These findings may also have been associated with the execution of each intervention. Previous studies have demonstrated that the anterior cingulate gyrus plays a key role in music processing in participants with dementia (Omar et al., 2011; Fletcher et al., 2015; Jacobsen et al., 2015), while the left middle frontal gyrus is associated with calculation (Maurer et al., 2016) and visual search (Weidner et al., 2009) in CS tasks. Therefore, our results indicate that the extent and location of brain atrophy at baseline may represent the neural basis of task execution for each intervention. In addition, these parameters may aid in predicting the efficacy of non-pharmacological treatment.
|
study
| 100.0 |
Previous studies have indicated that characteristic impairments across cognitive domains (Mori et al., 2016), Barthel Index (Formiga et al., 2010), and lower pre-treatment regional cerebral blood flow in the right orbitofrontal cortex (Hongo et al., 2008) can be used to predict better responses to cholinesterase inhibitors treatment in older adults with dementia. Our findings suggest that the efficacy of non-pharmacological treatment can also be predicted based on neural characteristics and the extent of cognitive decline.
|
study
| 99.94 |
The present study has some limitations of note. First, as we did not include healthy controls, further studies are required to investigate differences in neuropsychological factors and regional brain atrophy between healthy individuals and participants with mild-to-moderate dementia. Such findings may allow clinicians to predict the most appropriate non-pharmacological treatment for each participant. Second, the intervention period of the present study lasted only 6 months. Explicit differences in neuropsychological factors and regional brain atrophy may be more evident following a longer intervention period. Future studies should also aim to include a larger number of participants to enhance the accuracy of prediction.
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study
| 99.94 |
Our findings suggest that participants with mild-to-moderate dementia who have experienced cognitive decline, reduced ability to perform activities of daily living, and extensive cortical atrophy are less likely to exhibit IMPs in cognitive function following non-pharmacological treatment. Thus, some characteristics of pre-treatment cognitive dysfunction and regional brain atrophy may aid clinicians in determining the most appropriate non-pharmacological intervention for each participant.
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study
| 99.94 |
MS: conceived and designed the experiments. TT, NN, and KN: conducted the experiments. KT: analyzed the data. KT and MS: wrote the paper. JO: contributed materials. HK: analyzed and interpreted the data. HT: supervised and interpreted the data. All authors read and approved the final version of the paper.
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other
| 99.94 |
Norovirus was first reported in 1968 and has since placed a considerable disease burden upon economies and societies worldwide . This pathogen, which is characterized by high excreted viral loads , remarkable environmental survivability , extreme infectivity and short-term immunity , is now a leading cause of acute gastroenteritis across all age groups and is responsible for approximately 685 million cases and 200,000 deaths annually worldwide .
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other
| 99.9 |
Norovirus, a gastrointestinal virus, is thought to spread primarily by direct person-to-person contact or via foodborne, waterborne or environmental fomite routes . Although no evidence suggests that this virus is transmitted via the airborne route , the importance of this route has been suggested by several published reports . In terms of biological plausibility, the potential of airborne transmission of norovirus exists , based on the findings of virus-containing aerosol droplets produced by vomiting and toilet flushing , the detection of dispersed norovirus in the air , and the successful infection of mice via intranasal instillation . In terms of outbreak investigations, a few studies have claimed to provide evidence for the airborne transmission.
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review
| 91.94 |
To explore in greater detail the possibility of fomite versus airborne transmission of noroviruses, we reassessed the evidence in support of airborne transmission in a norovirus outbreak at a hotel restaurant in the UK in 1998 by testing whether the alternative fomite transmission route could have led to a similar pattern of secondary cases. The original investigation concluded that the outbreak was due to airborne transmission because the authors assumed that only the airborne route could have resulted in an attack rate that exhibited an inverse relationship with the distance from the index patient . Here, we demonstrate that with some waiters’ serving pathways and parameter values, a fomite transmission route could produce a similar pattern of secondary cases.
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study
| 100.0 |
Information about the ventilation system settings and restaurant size were not available, so we could not perform computational fluid dynamics simulations or multi-zone modelling of fluid dynamics analyses to determine the infection risk due to the airborne route; we instead investigated whether the fomite route could produce similar spatial attack rate patterns. Specifically, we applied a multi-agent model to simulate the transmission of noroviruses from the index patient to susceptible hosts via surface contact and calculated the exposure doses and infection risks. Seven representative serving pathways of waiters were considered under different scenarios, using various values for two important parameters: the dose-response parameter on the mucous membranes of gastrointestinal tracts, ηm, and the viral load, L0. For each scenario, least-squares fitting was used to compare the distributions of the predicted infection risks with those of the reported attack rates.
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study
| 100.0 |
The norovirus outbreak occurred during an evening dinner at a hotel restaurant , as shown in Figure 1. The index patient was a woman who vomited onto the floor at 8:30 p.m. The vomiting was not projectile, and the vomitus was rapidly cleaned by a waiter. Since handwashing of the lady and the waiter might not be effective enough , we assumed that very small amounts of norovirus were initially carried by the index patient’s and the waiter’s hands at the beginning of the outbreak (Table S5). Because the meal was not disturbed by the vomiting episode, the following 90 min were assumed to be the potential exposure period.
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clinical case
| 99.94 |
In this study, the guests and waiters were identified as the study objects, and the investigation focused on the infection patterns of the guests. After the outbreak, 83 of 126 guests from six parties were interviewed, 52 of whom reported illness. As shown in Figure 1, the distribution of attack rates showed a statistically significant spatial pattern . The attack rate was highest at Table 2, where the index patient was seated, while the rates at other tables decreased as the distance from Table 2 increased.
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| 100.0 |
The infection risks of various guests were predicted using a multi-agent modelling framework . This framework considered 12 kinds of representative surfaces (Table S1), which were categorized into four types of materials: porous surfaces, non-porous surfaces, skin and mucous membranes. The four types of surfaces differed regarding properties such as transfer rates (Table S2) and first-order inactivation rates (Table S3).
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study
| 100.0 |
Thirteen types of behavior, such as guests touching plates, guests shaking hands with others and waiters serving dishes, were assumed for both guests and waiters, and these assumed surface touching behaviors and their frequencies are summarized in Table S4. Because the six parties were discrete , it was assumed that guests did not shake hands with those at different tables. Seven types of pathways were considered regarding the behaviors of the waiters when serving dishes and wine. As shown in Figure 2A and Figure S1A, the waiters served guests at one table after another in anticlockwise and clockwise directions in Pathways 1 and 2, respectively. As shown in Figure 2C and Figure S1C, the waiters served guests at half of a table after another half in anticlockwise and clockwise directions in Pathways 3 and 4, respectively. As shown in Figure 2E and Figure S1E, the guests were divided into three groups of roughly equal size (Tables 1 and 2 and half of Table 3, the other half of Table 3 and Tables 4–6), and for every serving, each waiter served one group of guests in anticlockwise and clockwise directions in Pathways 5 and 6, respectively. As shown in Figure 2G, the waiters served guests randomly in Pathway 7.
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study
| 100.0 |
After initializing the surfaces, people and behaviors, we applied a surface contamination model to calculate the virus concentrations on different surfaces. The virus quantities on surfaces after one touching action only depend on the state before the action rather than the sequence of states that preceded it, which conforms to the definition of the Markov chain . Therefore, every behavior consisting of a series of touching actions can be regarded as a discrete-time Markov chain, while environmental surfaces and hand surfaces can be regarded as different states in the Markov chain. The surfaces of the mucous membranes are special surfaces so the exposure doses to the mucous membranes were calculated via the surface contamination model. Furthermore, a dose-response relationship model was used to predict the infection risk.
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study
| 100.0 |
To evaluate the possibility of the seven types of waiters’ serving pathways, we compared the predicted infection risk of each pathway to the reported attack rates using least-square fitting methods. Specifically, we calculated the residual sum of squares (RSS) as a measure of the fit for each pathway, and selected the probable pathway by maximizing fit (namely, minimizing RSS) .
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study
| 100.0 |
As suggested by references , the dose-response parameter on the mucous membranes, ηm, and the viral load, L0, strongly influence the infection risk distributions but might vary considerably among cases. According to the dose-response relationship model, we combined these two parameters as the product ηmL0 to reduce the number of variables and defined the product as the dose effect of introducing 1 g of norovirus-containing particles with a viral load of L0 to the mucous membranes. Based on the literature, we set a baseline scenario with a ηm of 0.1415/genome copy and a L0 of 3 × 108 genome copies/g and investigated different scenarios as the value of ηmL0 varied from 105 to 109/g.
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study
| 100.0 |
Figure 2B,D,F,H and Figure S1B,D,F present the average infection risk distributions of 1000 simulations involving the seven types of serving pathways at the end of the exposure period. In all simulations, the dose-response parameter on the mucous membranes, ηm, and the viral load, L0, were set as the baseline values.
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study
| 100.0 |
In this outbreak, the fomite transmission of norovirus between people occurred mainly via interactive behaviors such as hand shaking and waiters serving guests. Because it was assumed that the guests did not shake hands with those from other parties, hand shaking behavior merely influenced the regional distribution of the infection risk at each table. In contrast, the waiters’ serving behavior was not limited to single tables, which resulted in virus transmission between different tables. The waiter who initially carried the virus acted as a mobile virus source by which clean surfaces were contaminated, whereas other waiters acted as mobile media by which viruses were transmitted between surfaces. Thus, the overall infection risk distributions varied among the various serving pathway patterns (Figure 2 and Figure S1).
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study
| 100.0 |
Table 2, where the index patient was seated, had very high average infection risks for all serving pathways because the other diners at that table had the opportunity to shake hands with the index patient, during which large amounts of noroviruses were transmitted. The infection risk distribution patterns at other tables were consistent with the waiters’ pathways. In Pathways 1 and 2 (Figure 2A and Figure S1A, respectively), wherein the waiters served guests at one table after another, the average infection risks of diners at each table (except Table 2) decreased according to the pathway direction (Figure 2B and Figure S1B, respectively). In Pathways 3 and 4 (Figure 2C and Figure S1C, respectively), the waiters served guests at half of a table after another half, resulting in a considerable diversity of infection risks among diners at the same table of Tables 3–5. Therefore, the average infection risks at Tables 3–5 were similar to that of Table 6. Because the diners at Table 1 were visited by waiters either very early (Pathway 3) or very late (Pathway 4), the average infection risk at that table was accordingly either very high (Figure 2D) or very low (Figure S1D). In Pathways 5 and 6 (Figure 2E and Figure S1E, respectively), wherein each waiter served the guests of one group, the infection risk decreased in the direction of the pathway in each group (Figure 2F and Figure S1F, respectively). In Pathway 7 (Figure 2G), the waiters served guests randomly, resulting in similar average infection risks at each table, except Table 2 (Figure 2H).
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study
| 100.0 |
Figure 3 presents the fitness between the reported attack rates and predicted infection risks in different scenarios, while Table 1 lists the scenarios with the best fitness (the minimum RSS) for the seven types of serving pathways. According to the dose-response relationship model , the infection risk increased with the viral load, L0, and the dose-response parameter of the mucous membranes, ηm. Excessively small or large values of these two parameters yielded correspondingly too low or high infection risks that deviated considerably from the attack rates. Therefore, the best fitness was reached with moderate values of ηmL0, as shown in Figure 3 and Table 1.
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study
| 100.0 |
Of the seven pathways, Pathway 1 exhibits the best fitness because the corresponding predicted infection risk distribution was qualitatively similar to that of the attack rates. As shown in Table 1, the infection risk was highest at Table 2 and decreased from Tables 1–6. As shown in Figure 3, the scenario with the best fitness is very similar to the baseline scenario, indicating that the index patient in this outbreak probably shed a viral load, L0, similar to those reported by the literature , with a ηm of 0.1415/genome copy .
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study
| 100.0 |
This re-analysis was conducted to investigate the hypothesis that airborne transmission was responsible for this previously described hotel norovirus outbreak . The re-analysis was undertaken because hindsight and the subsequent investigation of many other outbreaks has called into question the proposed airborne transmission in the absence of support from fluid dynamics analyses. The dispersion of airborne virus-containing aerosols is mainly determined by the airflow pattern in an indoor environment. The high level of complexity of these airflow patterns can be attributed to many factors, such as differences in mechanical ventilation settings.
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study
| 100.0 |
In some outbreaks, such as the largest nosocomial SARS outbreak in Hong Kong , fluid dynamics analyses demonstrated a decrease in the predicted average aerosol concentration as the distance from the index patient increased. However, in some other outbreaks, such as the first nosocomial MERS outbreak in South Korea , fluid dynamics analyses predicted a higher average aerosol concentration in distant wards (i.e., downstream wards) than in adjacent wards. Since the distributions of infections transmitted via airborne routes are mainly decided by the dispersion of airborne aerosols , it do not necessarily present an inverse relationship with the distance from the source. Thus, to determine the infection patterns attributable to the airborne route, airflow-dynamic studies that model virus-laden aerosols generated by an index patient should be performed where possible .
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study
| 99.94 |
The results from this study indicate that given some reasonable assumptions about waiters’ serving pathways (e.g., Pathway 1), the infection risk attributable to the fomite route could exhibit an inverse relationship with the distance from the index patient, consistent with the attack rate distribution . In other words, the attack rate distribution patterns in this outbreak might have resulted from a fomite transmission route.
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study
| 99.94 |
Aside from this outbreak investigation , the evidence presented by other researchers in support of the airborne transmission of norovirus has been rather inconclusive. In a nosocomial outbreak in Toronto, reported by Sawyer et al. , housekeepers who visited or walked through the emergency room were more likely to become ill than those who did not encounter that area, and patients who visited the emergency room on 11 or 12 November were much more likely to develop infections than those who visited on 8 November. However, these characteristics could also be explained by fomite transmission because the surfaces surrounding the index patients would usually have been more contaminated and surface contamination would be much more severe at a later stage of the outbreak than at an earlier stage .
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study
| 99.94 |
Gellert et al. suggested airborne transmission mainly to explain the lack of evidence of direct fecal contact among several cases of infection. However, as the fluorescence experiments indicated, contaminants can spread to remote areas via the surface contamination network, wherein most contaminant transport between surfaces does not require direct contact with the original source.
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study
| 99.9 |
Several studies have assumed that the index patients’ vomiting episodes provided sufficient evidence of airborne transmission. Nevertheless, as Booth suggested experimentally , vomiting may contaminate a wide range of surfaces that are often difficult to clean sufficiently, thus increasing the likelihood of further transmission of surface contamination. Moreover, Marks et al. supported the possibility of airborne transmission because the time from exposure to illness decreased as the number of viral sources increased. However, as demonstrated by Lei et al. through simulations , an increase in the number of index patients could accelerate the transmission of surface contamination, thus increasing the accumulation of exposures and causing more rapid infection.
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study
| 99.94 |
Regarding infectivity, even if norovirus infection is possible via inhalation of airborne droplets, the infection risk associated with the airborne route is not comparable to that of the fomite route. Viruses with high survivability on environmental surfaces usually have a higher exposure dose via the fomite route than that via the airborne route . Moreover, unlike some respiratory viruses such as influenza , noroviruses should exhibit the same dose-response parameters for the airborne and fomite routes. The corresponding exposure site of norovirus, a gastrointestinal virus, is the gastrointestinal tract. The proposed airborne transmission would require inhaled aerosol droplets to be deposited in the upper respiratory tract and then be swallowed along with respiratory mucus .
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study
| 100.0 |
According to the dose-response relationship and assuming the same dose-response parameters, the fomite route with a higher exposure dose should be more important than the airborne route. Lei et al. investigated the relative contributions of norovirus transmission routes in a flight norovirus outbreak, and predicted contributions of 96% and 4% for the fomite and airborne routes, respectively. Therefore, the contribution of the airborne route to norovirus transmission might be negligible when compared with the fomite route, and increased effort should be invested into controlling the transmission of fomite contamination.
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study
| 99.94 |
This study had three limitations of note. First, detailed information about the ventilation systems and size of the restaurant are not available , so fluid dynamics analyses could not be performed. Therefore, the possibility of a long-range airborne route was not evaluated, and its relative importance versus the fomite route could not be accurately determined . Second, due to the limited understanding of some of the parameters of norovirus transmission, some parameters in the model, such as the rate of transfer from hands to porous surfaces (Table S2), were estimated from those of other viruses or even bacteria. This might have reduced the accuracy of the results. Third, given the lack of real-time observation data, the model included many assumptions about the common surfaces and the actual behaviors and movements of the guests and waiters (Table S4), which might have affected the infection risk distributions shown in Figure 2 and Figure S1. In general, more detailed outbreak information, laboratory measurements and human behavioral observations would be required to provide a more accurate analysis of norovirus transmission in this outbreak.
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study
| 100.0 |
This study re-examined the norovirus transmission routes in a previously reported hotel restaurant outbreak. With reasonable assumptions regarding the serving pathways of waiters and parameter values, the findings suggest that the observed spatial attack rate pattern could have resulted from the fomite transmission of norovirus (e.g., Pathway 1). This finding offers an alternative interpretation to the hypothesized airborne transmission route proposed by the original investigators of the outbreak. Furthermore, this study illustrates the need for a careful fluid dynamics analysis when evaluating the possibility of airborne transmission in an outbreak investigation. The results of this alternative transmission route analysis may assist the development of evidence-based infection control measures for norovirus outbreaks.
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study
| 100.0 |
To counter host defence mechanisms intracellular bacterial pathogens have evolved numerous strategies to evade immune detection, replicate and cause infection. Many pathogens manipulate endocytic pathways to gain entry into host cells and generate a membrane-enclosed replicative niche. This frequently involves hijacking or inhibiting the host cell trafficking machinery, first to generate the pathogen containing vacuole (PCV) and subsequently to prevent fusion with lysosomal degradative compartments. Concomitantly the pathogen often endeavors to decorate the PCV with host proteins and lipids that mimic other host cell organelles in order to circumvent innate immune detection, expand the replicative niche and acquire nutrients to support intracellular replication (Di Russo Case and Samuel, 2016; Personnic et al., 2016). This process is often orchestrated through the action of molecular syringe-like secretion systems that deliver bacterial effector proteins directly into the host cell cytoplasm.
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review
| 74.8 |
Chlamydia trachomatis is arguably one of the most successful human bacterial pathogens by virtue of its capacity to hijack host cell intracellular trafficking and lipid transport pathways to promote infection (Bastidas et al., 2013; Derré, 2015; Elwell et al., 2016; Moore and Ouellette, 2014). C. trachomatis causes nearly 100 million sexually transmitted infections annually worldwide, and if left unchecked leads to various human diseases including infection-induced blindness, pelvic inflammatory disease, infertility and ectopic pregnancy (Aral et al., 2006; Newman et al., 2015). Even though chlamydial infections can generally be treated with antibiotics, persistent infections remain a challenge (Kohlhoff and Hammerschlag, 2015; Mpiga and Ravaoarinoro, 2006).
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review
| 99.75 |
All Chlamydiae share a common dimorphic life cycle, where the bacteria alternates between the infectious but non-dividing elementary body (EB) form, and the non-infectious but replicative reticulate body (RB) form. Following internalization of EBs through a poorly defined endocytic process, the bacteria reside in a membrane-bound vacuole termed the inclusion, where they convert into RBs and replication occurs over 24–72 hr. RBs eventually redifferentiate back to EBs in an asynchronous manner, and are then released to infect neighboring cells (Di Russo Case and Samuel, 2016; Hybiske, 2015; Ward, 1983). The encapsulating inclusion membrane provides the primary interface between the bacteria and the host cell’s cytoplasm and organelles. From the initial stages of invasion until eventual bacterial egress the chlamydial inclusion is extensively modified by insertion of numerous Type-III secreted bacterial effector proteins called inclusion membrane proteins or ‘Incs’. The Incs modulate host trafficking and signaling pathways to promote bacterial survival at different stages, including cell invasion, inclusion membrane remodeling, avoidance of the host cell innate immune defense system, nutrient acquisition and interactions with other host cell organelles (Elwell et al., 2016; Moore and Ouellette, 2014; Rockey et al., 2002).
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study
| 99.9 |
Chlamydiae secrete more than fifty different Inc proteins. While Incs possess little sequence similarity, they share a common membrane topology with cytoplasmic N- and C-terminal domains, separated by two closely spaced transmembrane regions with a short intra-vacuolar loop (Dehoux et al., 2011; Kostriukova et al., 2008; Li et al., 2008; Lutter et al., 2012; Rockey et al., 2002) (Figure 1A). The cytoplasmic N- and C-terminal sequences of the Inc proteins act to bind and manipulate host cell proteins. Reported examples include the binding of the small GTPase Rab4A by CT229 (Rzomp et al., 2006), Rab11A by Cpn0585 (Cortes et al., 2007), SNARE proteins by IncA (Delevoye et al., 2008), centrosomal and cytoskeletal proteins by Inc850 and inclusion protein acting on microtubules (IPAM) (Dumoux et al., 2015; Mital et al., 2015, 2010), myosin phosphatase by CT228 (Lutter et al., 2013), 14-3-3 and Arf family proteins by IncG and InaC (Kokes et al., 2015; Scidmore and Hackstadt, 2001), and the lipid transfer protein CERT by IncD (Derré et al., 2011; Elwell et al., 2011). Despite these reports, there are no known structures of Inc family members either alone or in complex with host effectors.10.7554/eLife.22311.003Figure 1.SNX5, SNX6 and SNX32 tare recruited to C. trachomatis inclusions.(A) HeLa cells stably expressing the mCherry-Rab25 inclusion membrane marker (red) were infected with C. trachomatis serovar L2 (24 hr) and transfected with myc-tagged SNX expression constructs. The samples were fixed and immunolabeled with anti-myc (green) and anti-chlamydial HtrA antibodies (white) and counterstained with DAPI (blue). Similar experiments using GFP-tagged proteins are shown in Figure 1—figure supplement 1A.DOI: http://dx.doi.org/10.7554/eLife.22311.00310.7554/eLife.22311.004Figure 1—figure supplement 1.SNX5, SNX32 and SNX1 are recruited to C. trachomatis inclusions and membrane tubules.(A) Hela cells were transiently transfected with GFP-tagged SNX and mCherry-Rab25 proteins as indicated, and infected with C. trachomatis serovar L2. Cells were imaged by confocal fluorescence microscopy for GFP-tagged proteins (green), endogenous SNX1 (blue), mCherry-Rab25 (red) and DAPI-stained nuclear material (white). Both GFP-SNX5 and GFP-SNX32 are recruited to inclusion membranes, but the distantly related SNX-BAR protein SNX8 is not. The images are maximum projections. (B) An example of SNX1-decorated tubules (green) often observed emanating from inclusion membranes (mCherry-Rab25 in red; DAPI staining in blue). The image is a maximum projection.DOI: http://dx.doi.org/10.7554/eLife.22311.00410.7554/eLife.22311.005Figure 1—figure supplement 2.Recruitment of SNX1, SNX2 and SNX5 to inclusions is not dependent on 3-phosphoinositides.HeLa cells stably expressing mCherry-Rab25 were infected with C. trachomatis serovar L2 (MOI ~0.5) for 24 hr and imaged by immunofluorescence microscopy using antibodies to SNX1, SNX2 and SNX5. mCherry-Rab25 provides marker for the inclusion membrane. The upper panels show control infections and lower panels show cells treated with wortmannin or Vps34-IN1 with concomitant loss of SNX association with endosomal compartments while inclusion localisation is unaffected. The images are maximum projections. Endosomal compartments are labeled with antibodies to endogenous Rab5 or Vps35 and Pearson’s correlation coefficients used to quantify loss of endosomal recruitment (100 cells per group; error bars, S.D). A movie showing the effect of wortmannin on GFP-SNX5 is shown in Video 1.DOI: http://dx.doi.org/10.7554/eLife.22311.005
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study
| 99.94 |
(A) HeLa cells stably expressing the mCherry-Rab25 inclusion membrane marker (red) were infected with C. trachomatis serovar L2 (24 hr) and transfected with myc-tagged SNX expression constructs. The samples were fixed and immunolabeled with anti-myc (green) and anti-chlamydial HtrA antibodies (white) and counterstained with DAPI (blue). Similar experiments using GFP-tagged proteins are shown in Figure 1—figure supplement 1A.
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study
| 100.0 |
10.7554/eLife.22311.004Figure 1—figure supplement 1.SNX5, SNX32 and SNX1 are recruited to C. trachomatis inclusions and membrane tubules.(A) Hela cells were transiently transfected with GFP-tagged SNX and mCherry-Rab25 proteins as indicated, and infected with C. trachomatis serovar L2. Cells were imaged by confocal fluorescence microscopy for GFP-tagged proteins (green), endogenous SNX1 (blue), mCherry-Rab25 (red) and DAPI-stained nuclear material (white). Both GFP-SNX5 and GFP-SNX32 are recruited to inclusion membranes, but the distantly related SNX-BAR protein SNX8 is not. The images are maximum projections. (B) An example of SNX1-decorated tubules (green) often observed emanating from inclusion membranes (mCherry-Rab25 in red; DAPI staining in blue). The image is a maximum projection.DOI: http://dx.doi.org/10.7554/eLife.22311.004
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study
| 100.0 |
(A) Hela cells were transiently transfected with GFP-tagged SNX and mCherry-Rab25 proteins as indicated, and infected with C. trachomatis serovar L2. Cells were imaged by confocal fluorescence microscopy for GFP-tagged proteins (green), endogenous SNX1 (blue), mCherry-Rab25 (red) and DAPI-stained nuclear material (white). Both GFP-SNX5 and GFP-SNX32 are recruited to inclusion membranes, but the distantly related SNX-BAR protein SNX8 is not. The images are maximum projections. (B) An example of SNX1-decorated tubules (green) often observed emanating from inclusion membranes (mCherry-Rab25 in red; DAPI staining in blue). The image is a maximum projection.
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study
| 100.0 |
10.7554/eLife.22311.005Figure 1—figure supplement 2.Recruitment of SNX1, SNX2 and SNX5 to inclusions is not dependent on 3-phosphoinositides.HeLa cells stably expressing mCherry-Rab25 were infected with C. trachomatis serovar L2 (MOI ~0.5) for 24 hr and imaged by immunofluorescence microscopy using antibodies to SNX1, SNX2 and SNX5. mCherry-Rab25 provides marker for the inclusion membrane. The upper panels show control infections and lower panels show cells treated with wortmannin or Vps34-IN1 with concomitant loss of SNX association with endosomal compartments while inclusion localisation is unaffected. The images are maximum projections. Endosomal compartments are labeled with antibodies to endogenous Rab5 or Vps35 and Pearson’s correlation coefficients used to quantify loss of endosomal recruitment (100 cells per group; error bars, S.D). A movie showing the effect of wortmannin on GFP-SNX5 is shown in Video 1.DOI: http://dx.doi.org/10.7554/eLife.22311.005
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study
| 100.0 |
HeLa cells stably expressing mCherry-Rab25 were infected with C. trachomatis serovar L2 (MOI ~0.5) for 24 hr and imaged by immunofluorescence microscopy using antibodies to SNX1, SNX2 and SNX5. mCherry-Rab25 provides marker for the inclusion membrane. The upper panels show control infections and lower panels show cells treated with wortmannin or Vps34-IN1 with concomitant loss of SNX association with endosomal compartments while inclusion localisation is unaffected. The images are maximum projections. Endosomal compartments are labeled with antibodies to endogenous Rab5 or Vps35 and Pearson’s correlation coefficients used to quantify loss of endosomal recruitment (100 cells per group; error bars, S.D). A movie showing the effect of wortmannin on GFP-SNX5 is shown in Video 1.
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study
| 100.0 |
Two recent studies have greatly expanded the repertoire of host cell proteins known to associate with chlamydial inclusions and Inc proteins (Aeberhard et al., 2015; Mirrashidi et al., 2015). Both reports confirmed that membrane trafficking proteins are major components of the inclusion proteome; and in particular members of the endosomal sorting nexin (SNX) family are highly enriched. Specifically it was shown that the C. trachomatis IncE/CT116 protein could recruit SNX proteins containing bin-amphiphysin-Rvs (BAR) domains SNX1, SNX2, SNX5 and SNX6 (Mirrashidi et al., 2015). SNX1 and SNX2 are highly homologous and form heterodimeric assemblies with either SNX5 or SNX6 to promote endosomal membrane tubulation and trafficking (van Weering et al., 2012). A fifth protein SNX32 is highly similar to SNX5 and SNX6 but is almost exclusively expressed in the brain and has not yet been characterized. SNX recruitment to the inclusion occurs via the C-terminal region of IncE interacting with the phox-homology (PX) domains of SNX5 or SNX6 (Mirrashidi et al., 2015) (Figure 1A). Interestingly, RNAi-mediated depletion of SNX5/SNX6 does not slow infection but rather increases the production of infectious C. trachomatis progeny suggesting that the SNX recruitment is not done to enable bacterial infection. Instead it was proposed that because SNX proteins regulate endocytic and lysosomal degradation, the manipulation by IncE could be an attempt to circumvent SNX-enhanced bacterial destruction (Aeberhard et al., 2015; Mirrashidi et al., 2015).
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study
| 99.94 |
Here we use X-ray crystallographic structure determination to define the molecular mechanism of SNX5-IncE interaction, and confirm this mechanism using mutagenesis both in vitro and in cells. When bound to SNX5, IncE adopts an elongated β-hairpin structure, with key hydrophobic residues docked into a complementary binding groove encompassing a helix-turn-helix structural extension that is unique to SNX5, SNX6, and the brain-specific homologue SNX32. A striking degree of evolutionary conservation in the IncE-binding groove suggests that IncE co-opts the SNX5-related molecules by displacing a host protein (as yet unidentified) that normally binds to this site. Our work thus provides both the first mechanistic insights into how protein hijacking is mediated by inclusion membrane proteins, and also sheds light on the functional role of the SNX5-related PX domains as scaffolds for protein complex assembly.
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study
| 100.0 |
It was previously shown that the sorting nexins SNX1, SNX2, SNX5 and SNX6 are recruited to the inclusion membrane in C. trachomatis infected cells (Aeberhard et al., 2015; Mirrashidi et al., 2015). We first confirmed this for myc-tagged SNX1, SNX2 and SNX5 in HeLa cells infected with C. trachomatis serovar L2 (MOI ~0.5) for 18 hr. All three proteins were recruited to the inclusion membrane as assessed by co-localisation with the inclusion marker mCherry-Rab25 (Figure 1B) (Teo et al., 2016), as were GFP-tagged SNX1 and SNX5 but not the more distantly homologous GFP-SNX8 (Figure 1—figure supplement 1A). We also observed localization of the SNX proteins to extensive inclusion-associated membrane tubules in a subset of infected cells as described previously (Figure 1—figure supplement 1B) (Aeberhard et al., 2015; Mirrashidi et al., 2015). Interestingly, when infected cells are treated with wortmannin, a pan-specific inhibitor of phosphoinositide-3-kinase (PI3K) activity, we see a loss of the SNX proteins from punctate endosomes, but not from the inclusion membrane (Figure 1—figure supplement 2; Video 1). A similar result is seen for specific inhibition of PtdIns3P production by Vps34 using Vps34-IN1 (Figure 1—figure supplement 2). This offers two possibilities; that either SNX recruitment to the inclusion occurs via protein-protein interactions, and does not depend on the presence of 3-phosphoinositide lipids that typically recruit SNX proteins to endosomal membranes, or alternatively that PI3Ks are not present at the inclusion and therefore wortmannin treatment has no effect at this particular compartment. Given our structural and mutagenesis studies below we favor the former explanation.Video 1.Movie showing that wortmannin disrupts SNX5 recruitment to endosomes but not the chlamydial inclusion.HeLa cells stably expressing mCherry-Rab25 (red) were transfected transiently with GFP-SNX5 (green) and infected with Chlamydia trachomatis L2 for 24 hr. Time-lapse videomicroscopy was performed using an interval of 1 min on an inverted Nikon Ti-E deconvolution microscope with environmental control at 40 x magnification. 10 min into recording 100 nM wortmannin was added.DOI: http://dx.doi.org/10.7554/eLife.22311.00610.7554/eLife.22311.006
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| 100.0 |
HeLa cells stably expressing mCherry-Rab25 (red) were transfected transiently with GFP-SNX5 (green) and infected with Chlamydia trachomatis L2 for 24 hr. Time-lapse videomicroscopy was performed using an interval of 1 min on an inverted Nikon Ti-E deconvolution microscope with environmental control at 40 x magnification. 10 min into recording 100 nM wortmannin was added.
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| 99.94 |
Mirrashidi et al. (2015), demonstrated an in vitro interaction between IncE and the SNX5 and SNX6 PX domains. To confirm their direct association we assessed the binding affinities using isothermal titration calorimetry (ITC) (Figure 2A; Table 1). Initial experiments with the human SNX5 and SNX6 PX domains showed robust interactions with the IncE C-terminal domain (residues 107–132). The affinities (Kd) for SNX5 and SNX6 were essentially indistinguishable (0.9 and 1.1 µM respectively), but we detected no interaction with the PX domain of SNX1 confirming the binding specificity. The PX domains of SNX5 and SNX6 possess a helix-turn-helix structural insert (Koharudin et al., 2009), which is not found in any other SNX family members except for SNX32 (Figure 2B), a homologue expressed primarily in neurons (BioGPS (Wu et al., 2009)). Confirming a common recruitment motif in the SNX5-related proteins, ITC showed a strong interaction between IncE and the SNX32 PX domain similar to SNX5 and SNX6 (Kd = 1.0 µM) (Figure 2A; Table 1), and SNX32 was robustly recruited to inclusion membranes in infected cells (Figure 1B; Figure 1—figure supplement 1A). Overall, our data indicates that a common structure within the SNX5, SNX6 and SNX32 PX domains is required for IncE interaction.10.7554/eLife.22311.007Figure 2.IncE from C. trachomatis binds the PX domains of SNX5, SNX6 and SNX32.(A) Binding affinity between IncE peptide (residues 107–132) and SNX PX domains by ITC. Top panels show raw data and lower panels show normalised integrated data. See Table 1 for the calculated binding parameters. Truncation analyses of the IncE peptide by ITC are shown in Figure 3, Table 2. (B) Sequence alignment of human SNX1, SNX5, SNX6 and SNX32 PX domains. Conserved residues are indicated in red. Side-chains that directly contact IncE in the crystal structure are indicated with black circles. Mutations that block IncE binding are highlighted with red triangles, and mutations that do not affect binding indicated with green circles. Secondary structure elements derived from the SNX5 crystal structure are indicated above. (C) Sequence alignment of IncE from C. trachomatis and putative homologues from C. muridarum and C. suis. IncE side-chains that directly contact SNX5 in the crystal structure are indicated with black circles. Mutations that block SNX5 binding are highlighted with red triangles, and mutations that do not affect binding indicated with green circles. Predicted transmembrane regions are indicated and C-terminal IncE sequences that form β-strands in complex with SNX5 are shown.DOI: http://dx.doi.org/10.7554/eLife.22311.00710.7554/eLife.22311.008Table 1.Thermodynamic parameters of IncE binding to SNX PX domains*.DOI: http://dx.doi.org/10.7554/eLife.22311.008Sample cellTitrantKd (µM)△H (kcal/mol)T△S (kcal/mol)△G (kcal/mol)NSNX5 PXIncE peptide†0.95 ± 0.07−6.9 ± 0.3−1.9 ± 0.05−8.2 ± 0.011.01 ± 0.01SNX6 PXIncE peptide1.13 ± 0.08−5.0 ± 0.9−3.0 ± 1−8.0 ± 0.071.01 ± 0.08SNX32 PXIncE peptide1.15 ± 0.07−6.9 ± 0.4−1.3 ± 0.8−8.2 ± 0.41.06 ± 0.005SNX1 PXIncE peptideNo binding*Values are the mean from three experiments ±SEM.b.†IncE synthetic peptide sequence PANGPAVQFFKGKNGSADQVILVTQ.
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(A) Binding affinity between IncE peptide (residues 107–132) and SNX PX domains by ITC. Top panels show raw data and lower panels show normalised integrated data. See Table 1 for the calculated binding parameters. Truncation analyses of the IncE peptide by ITC are shown in Figure 3, Table 2. (B) Sequence alignment of human SNX1, SNX5, SNX6 and SNX32 PX domains. Conserved residues are indicated in red. Side-chains that directly contact IncE in the crystal structure are indicated with black circles. Mutations that block IncE binding are highlighted with red triangles, and mutations that do not affect binding indicated with green circles. Secondary structure elements derived from the SNX5 crystal structure are indicated above. (C) Sequence alignment of IncE from C. trachomatis and putative homologues from C. muridarum and C. suis. IncE side-chains that directly contact SNX5 in the crystal structure are indicated with black circles. Mutations that block SNX5 binding are highlighted with red triangles, and mutations that do not affect binding indicated with green circles. Predicted transmembrane regions are indicated and C-terminal IncE sequences that form β-strands in complex with SNX5 are shown.
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Finally we tested a series of IncE truncation mutants for their binding to the SNX5 PX domain (Figure 3A, B and C; Table 2). Synthetic peptides were used with single amino acids removed sequentially from the N and C-terminus to determine the minimal sequence required for binding. These experiments showed that the shortest region of IncE able to support full binding to SNX5 encompasses residues 110–131 (GPAVQFFKGKNGSADQVILVT), while a shorter fragment containing residues 113–130 (VQFFKGKNGSADQVILV) can bind to SNX5 with a slightly reduced affinity. While variations are observed across the different C. trachomatis serovars (Harris et al., 2012) the SNX5-binding sequence appears to be preserved in all detected variants (Figure 3D). A comparison with other chlamydial species suggests that IncE is not very widely conserved in this Genus, being clearly identifiable only in the closely related mouse pathogen C. muridarum and swine pathogen C. suis (Figure 2C). Residues required for binding to SNX5 are preserved in these IncE homologues, but whether SNX proteins are also recruited during infection by these other chlamydial species remains to be determined.10.7554/eLife.22311.009Figure 3.IncE residues 110–131 are sufficient for full recognition of the SNX5 PX domain.(A) Representative ITC experiments for truncated IncE peptides. These experiments were conducted using a single batch of SNX5 PX domain to minimize batch-to-batch protein variation. (B) Plots of the affinity constants for selected peptides to highlight the progressive loss of binding with N and C-terminal truncations. (C) Sequences of the truncated IncE peptides are given, with a qualitative indication of binding strength relative to the IncE_1 peptide containing residues 107–132. Full binding is indicated by ‘++’ reduced binding by ‘+’ and lack of binding by ‘−‘. All sequence information and their Kd values are given in Table 2. When compared to the reference ITC experiment the binding affinity of peptides was unaffected when the first three N-terminal residues were removed (IncE_2, IncE_3 and IncE_4) and gradually became weaker until IncE_7, after which binding was abolished. Results from IncE_6 are inconclusive due to the difficulty in successfully dissolving the peptides in buffer (n.d.). C-terminal truncations showed that IncE_14 and IncE_15 had similar high binding affinities to the reference, while the binding of IncE_16 and IncE_17 became progressively weaker and peptides shorter than IncE_17 showed no binding. This data indicates that the minimal IncE binding sequence retaining full SNX5 binding is GPAVQFFKGKNGSADQVILVT, and a shorter fragment VQFFKGKNGSADQVIL can bind to SNX5, albeit with a slightly reduced affinity. (D) Sequence alignment of IncE from different C. trachomatis serovars.DOI: http://dx.doi.org/10.7554/eLife.22311.00910.7554/eLife.22311.010Table 2.ITC data for SNX5 PX domain binding to truncated and mutated IncE peptides*.DOI: http://dx.doi.org/10.7554/eLife.22311.010ProteinPeptideSequenceKd (µM)△H (kcal/mol)T△S (kcal/mol)△G (kcal/mol)NSNX5 PXIncE_1PANGPAVQFFKGKNGSADQVILVTQ0.95 ± 0.07−6.9 ± 0.3−1.9 ± 0.05−8.2 ± 0.011.01 ± 0.01IncE_2 ANGPAVQFFKGKNGSADQVILVTQ1−5.0−2.6−8.10.98IncE_3 NGPAVQFFKGKNGSADQVILVTQ0.93−6.7−1.4−8.11.03IncE_4 GPAVQFFKGKNGSADQVILVTQ0.87−6.8−1.2−8.21.03IncE_5 PAVQFFKGKNGSADQVILVTQ2−5.9−1.2−8.30.99IncE_6 AVQFFKGKNGSADQVILVTQ/////IncE_7 VQFFKGKNGSADQVILVTQ2.2−6.9−1.1−7.70.99IncE_8 QFFKGKNGSADQVILVTQNo binding////IncE_9 FFKGKNGSADQVILVTQNo binding////IncE_10 FKGKNGSADQVILVTQNo binding////IncE_11 KGKNGSADQVILVTQNo binding////IncE_12 GKNGSADQVILVTQNo binding////IncE_13 KNGSADQVILVTQNo binding////IncE_14PANGPAVQFFKGKNGSADQVILVT0.72−5.1−1.6−8.41IncE_15PANGPAVQFFKGKNGSADQVILV0.97−6.5−1.3−8.20.98IncE_16PANGPAVQFFKGKNGSADQVIL1.1−5.6−1.4−8.120.99IncE_17PANGPAVQFFKGKNGSADQVI8.7−2.7−2.5−6.90.99IncE_18PANGPAVQFFKGKNGSADQVNo binding////IncE_19PANGPAVQFFKGKNGSADQNo binding////IncE_20PANGPAVQFFKGKNGSADNo binding////IncE_21PANGPAVQFFKGKNGSANo binding////IncE_22PANGPAVQFFKGKNGSNo binding////IncE_23PANGPAVQFFKGKNGNo binding////IncE_24PANGPAVQFFKGKNNo binding////IncE Q115APANGPAVAFFKGKNGSADQVILVTQ6.3−5.3−1.6−6.90.90IncE F116DPANGPAVQAFKGKNGSADQVILVTQNo bindingIncE K118APANGPAVQFFAGKNGSADQVILVTQ2.8−6.0−1.5−7.50.91IncE V127DPANGPAVQFFKGKNGSADQDILVTQNo bindingSNX5 PX L133DIncE_1PANGPAVQFFKGKNGSADQVILVTQNo bindingSNX5 PX F136AIncE_1PANGPAVQFFKGKNGSADQVILVTQNo bindingSNX5 PX E144AIncE_1PANGPAVQFFKGKNGSADQVILVTQ15−9.9−3.1−130.99*Except for IncE_1 all other peptide-binding experiments were performed only once.
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| 100.0 |
(A) Representative ITC experiments for truncated IncE peptides. These experiments were conducted using a single batch of SNX5 PX domain to minimize batch-to-batch protein variation. (B) Plots of the affinity constants for selected peptides to highlight the progressive loss of binding with N and C-terminal truncations. (C) Sequences of the truncated IncE peptides are given, with a qualitative indication of binding strength relative to the IncE_1 peptide containing residues 107–132. Full binding is indicated by ‘++’ reduced binding by ‘+’ and lack of binding by ‘−‘. All sequence information and their Kd values are given in Table 2. When compared to the reference ITC experiment the binding affinity of peptides was unaffected when the first three N-terminal residues were removed (IncE_2, IncE_3 and IncE_4) and gradually became weaker until IncE_7, after which binding was abolished. Results from IncE_6 are inconclusive due to the difficulty in successfully dissolving the peptides in buffer (n.d.). C-terminal truncations showed that IncE_14 and IncE_15 had similar high binding affinities to the reference, while the binding of IncE_16 and IncE_17 became progressively weaker and peptides shorter than IncE_17 showed no binding. This data indicates that the minimal IncE binding sequence retaining full SNX5 binding is GPAVQFFKGKNGSADQVILVT, and a shorter fragment VQFFKGKNGSADQVIL can bind to SNX5, albeit with a slightly reduced affinity. (D) Sequence alignment of IncE from different C. trachomatis serovars.
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| 100.0 |
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