Testing the efficacy of existing force-endurance models to account for the prevalence of obesity in the workforce

This study evaluates whether the existing force-endurance relationship models are predictive of endurance time for overweight and obese individuals, and if not, provide revised models that can be applied for ergonomics practice. Data was collected from 141 participants (49 normal weight, 50 overweight, 42 obese) who each performed isometric endurance tasks of hand grip, shoulder flexion, and trunk extension at four levels of relative workload. Subject-specific fatigue rates and a general model of the force-endurance relationship were determined and compared to two fatigue models from the literature. There was a lack of fit between previous models and the current data for the grip (ICC = 0.8), with a shift toward lower endurance times for the new data. Application of the revised models can facilitate improved workplace design and job evaluation to accommodate the capacities of the current workforce.     

Can passive pedaling improve sexual function in patients under hemodialysis? A randomized clinical trial

To investigate the effect of passive pedaling with mini bike on sexual function in patients under hemodialysis. This study was a randomized clinical trial. Thirty-seven patients undergoing hemodialysis were assigned to the intervention (n = 20) and control (n = 17) groups by the stratified block randomization method. The intervention group exercised with a mini bike that was automatic and tuned for patients during the first 2 h of dialysis, twice a week for 20 min each time, for 3 months. The International Index of Erectile Function and Female Sexual Function Index were used to assess the sexual function in the first, second, and third months during the intervention and one month after the intervention. A higher score indicates a better sexual function. Repeated measure ANOVA, Chi–square and Fisher exact tests, independent t, and Mann–Whitney U tests were used for data analysis. The SPSS software version 22 was used for data analysis. Sexual function scores of the intervention group were 35.9 at the beginning of the study, 34.1 in the first month, 37.4 in the second month, 34.8 in the third month, and 31.7 one month after the study. There was no significant difference in the scores of sexual function in the intervention group during the study. The mean scores of sexual function in the control group were 34.5, 34.4, 34.9, 33.8, and 33.9 at the beginning of the study, in the first month, in the second month, in the third month, and one month after the study, respectively (p > 0.05). There was no significant difference between the two groups in terms of sexual function scores during and after the intervention (p > 0.05). Passive pedaling with mini-bike had no effect on sexual function of hemodialysis patients.     

Dose-proportional pharmacokinetics of d-threo-methylphenidate after a repeated-action release dosage form

A bimodal extended-release formulation of d-methylphenidate (d-MPH) has been developed to enable fast onset of action and once-daily administration in patients with attention deficit hyperactivity disorder. The authors studied the dose proportionality of extended-release d-MPH pharmacokinetics. Twenty-five healthy adult volunteers received 5, 10, 20, 30, and 40 mg d-MPH in a crossover study with 7 days between doses. All doses were well tolerated. Dose proportionality was shown for all dose-dependent pharmacokinetic parameters. Geometric means (%gCV) for the first Cmax peak, Cmax0-4, were 3.25 (29.0%), 6.05 (27.1%), 12.6 (31.9%), 18.5 (31.9%), and 25.2 ng/mL (29.3%) for d-MPH 5, 10, 20, 30, and 40 mg, respectively. Geometric means (%gCV) for Cmax4-10 were 3.18 (27.5%), 5.84 (27.7%), 12.5 (31.7%), 17.7 (31.6%), and 23.6 ng/mL (29.0%), respectively. Geometric means for AUC(0-infinity) were 24.3 (30.7%), 45.9 (30.2%), 96.4 (35.5%), 144 (33.3%), and 195 ng x h/mL (30.9%), respectively. The pharmacokinetics of once-daily extended-release d-MPH are proportional to the dose.     

Neuronal death by repetitive cortical spreading depression in juvenile rat brain

Spreading depression (SD) is an intrinsic bioelectrical property of the human central nervous system, which plays a key role in neurological disorders. In the present study, we investigated whether experimentally induced repetitive SD caused neuronal death in cortical and subcortical regions of the juvenile rat brain. The animals were anesthetized and the electrodes as well as a cannula were implanted over the brain. Repetitive cortical SD events were induced by KCl injection. The brains were removed after 4 weeks. Repetitive SD enhanced the production of dark neurons, reduced the mean volume of normal neurons, increased the number of apoptotic neurons, and enhanced expression of the NR(2B) subunit of NMDA receptors as well as the GluR1 subunit of AMPA receptors in various regions of the juvenile rat brain. In addition, induction of repetitive SD enhanced long-term potentiation in CA1 hippocampal area. We observed a correlation between cell injury/neuronal death induced by repetitive SD and changes in glutamate receptor expression. The data indicate that repetitive cortical SD in juvenile rats causes neuronal damage in both cortical and subcortical areas of the brain. This may play an important role in the pathophysiology of SD-related neurological disorders, especially in children.     

The underlying factor structure of National Institutes of Health Stroke scale: an exploratory factor analysis

The underlying structure of National Institutes of Health Stroke Scale (NIHSS) as the most widely used scale in clinical trials has been the focus of little attention. The aim of the current study was to elucidate the clustering pattern of NIHSS items in ischemic stroke patients. A series of 152 consecutive patients with first-ever ischemic strokes admitted to a university affiliated hospital were enrolled. NIHSS score was estimated on admission and correlation coefficients between its items were calculated. Further, exploratory factor analysis was used to study the clustering pattern of NIHSS items. Extinction neglect, visual field, and facial palsy were weakly associated with other NIHSS items. Factor analysis led to a four-factor structure. Factors 1 and 3 were determined by left brain function as items of right arm and leg motor, language and dysarthria loaded on both of them. By contrast, factor 2 reflected right brain involvement. Since visual field and ataxia loaded on factor 4, this factor was primarily associated with posterior strokes. Our study shows that a four-factor structure model is plausible for NIHSS. Further, for the first time, a single distinct factor is identified for posterior strokes.     

Occurrence of Potentially Pathogenic Bacterial-Endosymbionts in Acanthamoeba Spp.

Background:

Acanthamoeba- bacteria interactions enable pathogenic bacteria to tolerate harsh conditions and lead to transmission to the susceptible host. The present study was aimed to address the presence of bacterial endosymbionts of Acanthamoeba isolated from recreational water sources of Tehran, Iran. To the best of our knowledge this is the first study regarding occurrence of bacteria in environmental Acanthamoeba spp. in Iran.

Methods:

A total of 75 samples of recreational water sources were collected. Samples were cultured on non- nutrient agar 1.5% plates. Positive Acanthamoeba spp. were axenically grown. DNA extraction and PCR reaction was performed using JDP1-2 primers. All positive samples of Acanthamoeba were examined for the presence of endosymbionts using staining and molecular methods. The PCR products were then sequenced in order to determine the genotypes of Acanthamoeba and bacteria genera.

Results:

Out of 75 samples, 16 (21.3%) plates were positive for Acanthamoeba according to the morphological criteria. Molecular analysis revealed that Acanthamoeba belonged to T4 and T5 genotypes. Five isolates (35.7%) were positive for bacterial endosymbionts using staining method and PCR test. Sequencing of PCR products confirmed the presence of Pseudomonas aeruginosa and Agrobacterium tumefasiens.

Conclusion:

The presence of Acanthamoeba bearing pathogenic endosymbionts in water sources leads us to public health issues including improved sanitation and decontamination measures in recreational water sources in order to prevent amoebae-related infection. To the best of our knowledge this is the first report regarding the isolation of A. tumefasiens from Acanthamoeba in Iran and worldwide.     

Pulsatile blood flow in total cavopulmonary connection: a comparison between Y-shaped and T-shaped geometry

Single-ventricle anomaly is a hereditary heart disease that is characterized by anatomical malformations. The main consequence of this malformation is desaturated blood flow, which without proper treatment increases the risk of death. The classical treatment is based on a three-stage palliative procedure which should begin from the first few days of patient’s life. The final stage is known as Fontan procedure, in which inferior vena cava is directly connected to pulmonary arteries without going through the ventricle. This connection is called total cavopulmonary connection (TCPC). After surgery, the single ventricle supplies adequate and saturated systemic blood flow to the body; however, TCPC contains low pressure and low flow pulsatility. To overcome this problem, a new method is proposed wherein pulsatile blood will be directed to the TCPC through the stenosed main pulmonary artery. In this study, through the use of Computational Fluid Dynamics, T-shaped (MRI-based) and Y-shaped (computer-generated) geometries are compared in order to determine the influence of this modification on pulsation of blood flow as well as energy loss in pulmonary arteries. The results indicate that energy loss in Y-shaped geometry is far less than T-shaped geometry, while the difference in flow pulsatility is insignificant.