Multi-camera imaging to characterize jet and liner uniformity on the Plasma Liner Experiment (PLX)

At Plasma Liner Experiment, a set of 36 coaxial plasma guns are deployed quasi-uniformly over a 9 ft diameter spherical chamber and are used to form a high-Z spherically compressive plasma liner. Simulations indicate that for the concept to ultimately achieve optimal target density and temperature, a high degree of timing uniformity is required between all guns. To aid in quantifying and correcting gun-to-gun nonuniformities, a key diagnostic will consist of up to six fisheye-view CCD cameras positioned inside the main chamber such that each has all plasma guns within its view. The individual cameras can be triggered at different times to determine each plasma jet's muzzle velocity and structure for different operating conditions. This camera array is currently under development, and the implementation needs and challenges for this camera array are discussed here. Additionally, we detail the analysis methodology for determining jet-to-jet uniformity deviations and how we can correct them, thereby improving overall liner uniformity.

Energetics of the Glycosyl Transfer Reactions of Sucrose Phosphorylase

From its structure and mechanism, sucrose phosphorylase is a specialized glycoside hydrolase that uses phosphate ions instead of water as the nucleophile of the reaction. Unlike the hydrolysis reaction, the phosphate reaction is readily reversible and, here, this has enabled the study of temperature effects on kinetic parameters to map the energetic profile of the complete catalytic process via a covalent glycosyl enzyme intermediate. Enzyme glycosylation from sucrose and α-glucose 1-phosphate (Glc1P) is rate-limiting in the forward (k_cat = 84 s^-1) and reverse direction (k_cat = 22 s^-1) of reaction at 30 °C. Enzyme-substrate association is driven by entropy (TΔS_b ≥ +23 kJ/mol), likely arising from enzyme desolvation at the binding site for the leaving group. Approach from the ES complex to the transition state involves uptake of heat (ΔH^⧧ = 72 ± 5.2 kJ/mol) with little further change in entropy. The free energy barrier for the enzyme-catalyzed glycoside bond cleavage in the substrate is much lower than that for the non-enzymatic reaction (k_non), ΔΔG^⧧ = ΔG_non^⧧ - ΔG_enzyme^⧧ = +72 kJ/mol; sucrose. This ΔΔG^⧧, which also describes the virtual binding affinity of the enzyme for the activated substrate in the transition state (∼10¹⁴ M^-1), is almost entirely enthalpic in origin. The enzymatic rate acceleration (k_cat/k_non) is ∼10¹²-fold and similar for reactions of sucrose and Glc1P. The 10³-fold lower reactivity (k_cat/K_m) of glycerol than fructose in enzyme deglycosylation reflects major losses in the activation entropy, suggesting a role of nucleophile/leaving group recognition by the enzyme in inducing the active-site preorganization required for optimum transition state stabilization by enthalpic forces.

Predictors of acute pulmonary embolism-related hospitalizations – an artificial neural network analysis using a nationwide cohort in the United States

Background

Considering a paucity of large-scale data on predictors of pulmonary embolism (PE) and its higher association with complications and worse outcomes, we aimed to determine the predictors of PE in this United States population-based analysis using Artificial Neural Network (ANN) Model in a nationally representative cohort.

Methods

We identified PE-related hospitalizations using 2018's National Inpatient Sample database. The relevant predictive factors for ANN were selected for this cohort. Of all admissions (unweighted n=7,105,498, weighted n=35,527,481), PE cohort (weighted n=387805) consisted of 1.1% of all admissions in 2018. The 2018 cohort was randomly split into training data (unweighted n=4716132, 70.0%) which were used to calibrate ANN and testing data (unweighted n=2019290, 30%) which were used to assess the accurateness of the algorithm. We equated the rate of incorrect prediction between training and testing data and measured the Area under Receiver Operator Curve (AUC) to determine ANN's efficacy in predicting PE hospitalizations.

Results

Patients hospitalized with PE often consisted of older (mean age 62.5±17.1 years), female (51.3%), white (70.5%) patients, and patients from lower-income quartile (0–25% income quartile: 28.8%%), often admitted non-electively (93.7%) with higher rates of cardiovascular disease risk factors. PE admissions revealed significantly higher (6.5% vs. 1.9%, p<0.001) in-hospital mortality, less frequent routine discharges (51.4% vs. 68.1%) and more frequent other facility transfers and requirement of home health care. Normalized Predictors of PE admissions are displayed in Fig. 1. Our ANN model had AUC 0.873 which correlates with an excellent prediction model. Our data demonstrated low levels (0.8%) error in both testing and training models.

Conclusion

Our ANN model showed high performance to predict risk factors for PE admissions in the US population. It will enable clinicians to screen patients at high-risk for PE admissions, curtail complication rate, improve survival and lower the healthcare cost.

Funding Acknowledgement

Type of funding sources: None.

Novel Two-Step Process in Cellulose Depolymerization: Hematite-Mediated Photocatalysis by Lytic Polysaccharide Monooxygenase and Fenton Reaction

To transform cellulose from biomass into fermentable sugars for biofuel production requires efficient enzymatic degradation of cellulosic feedstocks. The recently discovered family of oxidative enzymes, lytic polysaccharide monooxygenase (LPMO), has a high potential for industrial biorefinery, but its energy efficiency and scalability still have room for improvement. Hematite (α-Fe₂O₃) can act as a photocatalyst by providing electrons to LPMO-catalyzed reactions, is low cost, and is found abundantly on the Earth's surface. Here, we designed a composite enzymatic photocatalysis-Fenton reaction system based on nano-α-Fe₂O₃. The feasibility of using α-Fe₂O₃ nanoparticles as a composite catalyst to facilitate LPMO-catalyzed cellulose oxidative degradation in water was tested. Furthermore, a light-induced Fenton reaction was integrated to increase the liquefaction yield of cellulose. The innovative approach finalized the cellulose degradation process with a total liquefaction yield of 93%. Nevertheless, the complex chemical reactions and products involved in this system require further investigation.

Vitamin D supplementation and clinical outcomes in COVID-19: a systematic review and meta-analysis

PURPOSE

To provide a precise summary and collate the hitherto available clinical evidence on the effect of vitamin D supplementation on clinical outcomes in COVID-19 patients.

METHODS

PubMed/MEDLINE, Scopus, and Web of Science databases were systematically searched using appropriate keywords till June 8, 2021, to identify observational studies and randomized controlled trials (RCTs) reporting adverse clinical outcomes (ICU admission and/or mortality) in COVID-19 patients receiving vitamin D supplementation vs. those not receiving the same. Both prior use and use of vitamin D after COVID-19 diagnosis were considered. Unadjusted/adjusted pooled odds ratio (OR) with 95% confidence intervals (CI) were calculated (PROSPERO registration number CRD42021248488).

RESULTS

We identified 13 studies (10 observational, 3 RCTs) pooling data retrieved from 2933 COVID-19 patients. Pooled analysis of unadjusted data showed that vitamin D use in COVID-19 was significantly associated with reduced ICU admission/mortality (OR 0.41, 95% CI: 0.20, 0.81, p = 0.01, I2 = 66%, random-effects model). Similarly, on pooling adjusted risk estimates, vitamin D was also found to reduce the risk of adverse outcomes (pooled OR 0.27, 95% CI: 0.08, 0.91, p = 0.03, I2 = 80%, random-effects model). Subgroup analysis showed that vitamin D supplementation was associated with improved clinical outcomes only in patients receiving the drug post-COVID-19 diagnosis and not in those who had received vitamin D before diagnosis.

CONCLUSIONS

Vitamin D supplementation might be associated with improved clinical outcomes, especially when administered after the diagnosis of COVID-19. However, issues regarding the appropriate dose, duration, and mode of administration of vitamin D remain unanswered and need further research.

Comparing loading strategies of P2Y12 inhibitors in patients undergoing elective PCI: a network meta-analysis

Introduction

Effective platelet inhibition prior to elective percutaneous coronary intervention (PCI) reduces the risk of ischemic complications. Newer P2Y12 inhibitors are preferred agents over clopidogrel for patients presenting with acute coronary syndrome. However, the comparative efficacy and safety of them over clopidogrel in elective PCI is unclear. Our objective was to perform a network meta-analysis and assess that from randomized controlled trials (RCT).

Methods

We conducted a systematic review of RCTs up to and including November 2020. The endpoints of interest were overall mortality, rates of myocardial infarction (MI), stroke, revascularization and major bleeding. Random effects model using frequentist approach was used to perform a network meta-analysis using R software.

Results

5 trials with total of 5,194 patients were included in our analysis. For ischemic outcomes including MI, Stroke and revascularization, prasugrel had the most favorable trend. However, clopidogrel had the highest probability of being most effective for major bleeding and all-cause mortality. None of these trends were statistically significant due to lack of power for each individual outcome (Figure 1).

Conclusion

Prasugrel and ticagrelor seem to show better efficacy in preventing MI and stroke. However, their effects are marginal and do not translate into improved overall mortality and bleeding. Therefore, in this lower risk population presenting for elective PCI, clopidogrel remains a reasonable P2Y12 inhibitor choice in lower risk population.

Funding Acknowledgement

Type of funding sources: None. Results

A comparative study on the chemo-enzymatic upgrading of renewable biomass to 5-Hydroxymethylfurfural

5-hydroxymethylfurfural (HMF) obtained from renewable biomass-derived carbohydrates is a potential sustainable substitute to petroleum-based building blocks. In the present work, we constituted a comparative study on the production of HMF from two widely available real biomasses in India- Agave americana and Casuarina equisetifolia. In the initial hydrolysis studies for the production of reducing sugars, 649.5 mg/g of fructose was obtained from the hydrolysis of 5% (w/v) A. americana biomass by the enzyme inulinase in 3 h at 50°C. Similarly, upon hydrolysis of 15% (w/v) C. equisetifolia biomass by the lignocellulolytic enzymes (laccase, cellulase and xylanase) from Trichoderma atroviride, 456.65 mg/g of reducing sugars was released in 24 h at 30°C. Subsequently, the dehydration of the obtained reducing sugars to HMF was achieved with titanium dioxide as the catalyst. The dehydration of A. americana-derived fructose at 140°C led to a maximum HMF yield of 92.6% in 15 min with 10% catalyst load. Contrarily, upon optimizing the process parameters for dehydration of C. equisetifolia derived reducing sugars, the maximum HMF yield of 85.7% was obtained at 110°C in 25 min with a TiO₂ concentration of 10%. This study reports for the first time the utilization of C. equisetifolia biomass for HMF production and thus, by utilizing these inexpensive, abundantly available and highly functionalized polysaccharides, a strategical approach can be developed for the production of fine chemicals, eliminating the need of fossil-based chemicals. Implications: The catalytic upgrading of lignocellulosic biomass into high-valued platform chemicals like 5-Hydroxymethylfurfural (HMF) implies an extremely significant challenge to the attempts of establishing a green economy. Casuarina equisetifolia and Agave americana represents a sustainable feedstock for the production of HMF through catalytic integration. The present work describes a two-step reaction process where the initial depolymerization step comprises of an enzymatic hydrolysis followed by a chemical-catalyst mediated dehydration process. The utilization of a biocatalytic approach followed by mild chemical catalyst eliminates the need of hazardous chemical conversion processes. Thus, the HMF produced via sustainable can bridge the gap between carbohydrate chemistry and petroleum-based industrial chemistry because of the wide range of chemical intermediates and end-products that can be derived from this compound.

Surgical cardiac sympathetic denervation in patients with VT storm: long term follow-up data

Background

Surgical Cardiac Sympathetic Denervation (CSD) is a procedure which involves surgical removal of terminal cervical and thoracic sympathetic ganglion for reducing sympathetic discharge to the heart. CSD is usually performed as a last desperate measure in treatment of ventricular tachycardia (VT). We report here the clinical profile and long-term follow-up of all our patients who underwent CSD (unilateral or bilateral) predominantly upfront prior to considering catheter ablation of VT for VT storm.

Material and methods

We retrospectively collected data of all patients who underwent CSD for VT storm between year 2010 till 2019. Success of CSD was defined as successful discharge of patient from the hospital after the procedure more than 75% decrease in the frequency of VT after two weeks of surgical procedure.

Results

A total of 65 patients underwent CSD in the above-mentioned period and the average duration of follow-up was 28 months. The clinical parameters, demographic data and outcome analysis is provided in details in table 1. Only 14 (21.5%) patients underwent attempt of catheter ablation of VT prior to considering CSD. CSD was successful in 53 (81.5%) of patients. There was a significant decline in the incidence of number of ICD or external shocks before and after CSD (25.2±39.4 vs 1.09±2.9) respectively. There was no significant effect of CSD on ejection fraction. None of the available clinical parameters predicted the success of CSD.

Discussion and conclusion

The current retrospective analysis reemphasize the role of surgical CSD in treatment of patients with VT storm. As in predominant patient's CSD was performed even before the attempting catheter-based ablation, it brings in a new dimension in the treatment of VT. Efficacy of CSD (81.5%) in experienced hand is equivalent or even better than catheter-based ablation in patients with VT storm.

Funding Acknowledgement

Type of funding source: None

Community-based active case-finding to reach the most vulnerable: tuberculosis in tribal areas of India

<sec> <title>BACKGROUND</title> India has the world's largest indigenous/tribal population. Many areas with large tribal populations suffer from weak infrastructure and services. Surveys have shown a high prevalence of TB among Saharia communities, who rarely access public services. We evaluated a community-based active TB case-finding intervention. </sec> <sec> <title>METHODS</title> Community health workers screened people for TB symptoms in Saharia communities, made referrals, collected sputum for transport to laboratories, and initiated and supported anti-tuberculosis treatment. Microscopy testing was performed at government laboratories. The intervention tracked the people screened, referrals, the people tested, laboratory results, treatment initiation and outcomes. </sec> <sec> <title>RESULTS</title> Community health workers verbally screened 65 230 people, 8723 (13%) of whom had symptoms. Of these, 5600 were tested, 964 (17%) of whom were smear-positive. During the intervention, we observed a +52% increase in people tested at laboratories and an +84% increase in TB case notifications. Pre-treatment loss to follow-up decreased and treatment success increased slightly. </sec> <sec> <title>CONCLUSIONS</title> In India, particularly among tribal populations, many people with TB are missed by current approaches due to poor access. Community-based active case-finding can help identify more people with TB in tribal and remote rural areas by addressing barriers to health seeking as well as help reach ambitious country and global notification targets. </sec>.

Costs and operation management of community outreach program for tuberculosis in tribal populations in India

Objective

To evaluate costs of an active case finding (ACF) program with tuberculosis (TB) treatment delivery and monitoring, which targeted a rural tribal population in India.

Method

A time and motion study was conducted to evaluate operations and workload. Costs from the program perspective were assessed using both the bottom-up and top-down costing methods, exclusive of routine TB care costs. The impact of ACF on routine TB laboratory workloads was measured based on the changes in available staff time per smear at nine designated microscopy centers before and after program implementation.

Results

A majority (53.2%) of the community health-care worker's time was spent in traveling to communities, with an average of 22 TB patients (95% CI 19.14-24.94) seen per day per person. Costs (at 2015 $US rates) were US$1.85-US$2.42 per patient screened and submitting sputum, US$2.51-US$4.74 per person diagnosed with TB, and US$22.52-US$34.13 per TB patient completing treatment. Total smear volumes increased significantly after the ACF program, with more than a 15% reduction in available staff time per sputum smear test in most laboratories.

Conclusion

This low-cost, ACF program has the potential to be highly cost-effective in addressing gaps in TB care problems in rural India.

Preparation of 4-Deoxy-L-erythro-5-hexoseulose Uronic Acid (DEH) and Guluronic Acid Rich Alginate Using a Unique exo-Alginate Lyase from Thalassotalea crassostreae

Marine multicellular algae are considered promising crops for the production of sustainable biofuels and commodity chemicals. However, their commercial exploitation is currently limited by a lack of appropriate and efficient enzymes for converting alginate into metabolizable building blocks, such as 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH). Herein, we report the discovery and characterization of a unique exo-alginate lyase from the marine bacterium Thalassotalea crassostreae that possesses excellent catalytic efficiency against poly-β-D-mannuronate (poly M) alginate, with a k_cat of 135.8 s^-1, and a 5-fold lower k_cat of 25 s^-1 against poly-α-L-guluronate (poly G alginate). We propose that this preference for poly M is due to a structural feature of the protein's active site. The mode of action and specificity of this enzyme has made it possible to design an effective and environmentally friendly process for the production of DEH and low molecular weight guluronate-enriched alginate.

Sugar before bed: a simple dietary risk factor for caries experience

Clinical care pathways have placed renewed emphasis on caries risk assessment and the ability to predict and prevent further disease. With diet considered a key factor in the development of caries, the level of caries risk posed by dietary habits, such as the frequency of intake and timing of free sugars is questioned.

OBJECTIVE

To identify reliable and simple dietary risk factors for caries experience.

RESEARCH DESIGN

A cross-sectional observational study of a convenience sample with data gained from clinical examinations, questionnaire and a 24 hour dietary-recall interview.

PARTICIPANTS

128 subjects aged 11-12 from comprehensive schools in Greater Manchester and Newcastle upon-Tyne, UK.

OUTCOME MEASURES

free sugars consumed between meals, before bed and total % of total free sugars consumed were assessed from dietary assessments led by a dietitian. D4-6MFT was generated with a caries threshold of ICDAS stage 4 from clinical examinations.

RESULTS

Analysis revealed no significant differences in caries experience when looking specifically at caries into dentine, referred to as the cavity group (split at D4-6MFT), between high and low deprivation, consumption of free sugars between meals and free sugars (%). The consumption of free sugars within the hour before bed revealed a statistically significant difference between the cavity/no cavity groups (p=0.002). Logistic regression analysis on the cavity/no cavity groups revealed an odds ratio of 2.4 (95%CI 1.3,4.4) for free sugars consumption before bedtime.

CONCLUSIONS

The study suggests that the consumption of free sugars before bedtime may be an important risk factor for adolescent caries into dentine experience.

Public health matters: Innovative approaches for engaging medical students

BACKGROUND

Public health faces the paradox of being increasingly emphasized by the key health and social care regulators and stakeholders, while remaining a largely under-represented discipline in the context of medical curricula. Enhancing medical student engagement in public health teaching is one way to address this concern.

METHODS

We discuss four key solutions to the challenges faced by public health educators in medical schools, and present five case studies which demonstrate innovative approaches to engaging medical students in our discipline.

RESULTS

Four different approaches have been piloted by members of the Public Health Educators in Medical Schools (PHEMS) network: (i) ensuring social accountability, (ii) demonstrating clinical relevance, (iii) mapping the core curriculum, and (iv) using technology enhanced learning. Preliminary student feedback suggests that these approaches can be used to position public health as an enabler of modern medical practice, and promote a more holistic understanding of medicine by linking patient-centred care to the population level.

CONCLUSIONS

The zeitgeist in both academia and the healthcare system supports the teaching of public health within the medical curriculum; there is also consensus at the political and pedagogical level. The challenge of ensuring engagement now needs to be met at the student-teacher interface.

The VCDQ--a Questionnaire for symptom monitoring in vocal cord dysfunction

BACKGROUND

Vocal cord dysfunction (VCD) typically involves abnormal adduction of the vocal cords during inspiration, mimics the symptoms of asthma and leads to the prescription of ineffective medications.

OBJECTIVE

We aimed to develop a clinical tool to monitor symptoms and response to treatment in confirmed VCD.

METHODS

We collated symptoms of VCD from focus groups comprising patients and healthcare professionals; phrases describing these symptoms were assessed for face validity and internal correlation and rated for importance. The resultant 12-item questionnaire (VCDQ) rated the impact of each on a 5-point Likert scale (total score range 12-60) and was tested for reliability, concurrent validity and performance in 31 patients with endoscopically confirmed VCD (± asthma), 29 asthmatics with no history of VCD and 14 healthy controls. We assessed response to speech and language therapy and the minimal important difference by measuring the VCDQ pre- and post- therapy in a 20 new patients.

RESULTS

The VCDQ had excellent test-retest reliability and differentiated VCD vs. healthy (Mann-Whitney U-test: z = -5.390, P < 0.001) and asthma (z = -5.730, P < 0.001). All patients improved post-therapy, assessed both by a global rating of change score (GRCS) and by the VCDQ [median (IQR) score pre-therapy 50.5 (48.0 - 54.8), post-therapy 35.0 (29.3 - 41.8), P < 0.001]. The minimal important difference in the VCDQ associated with a rating of 'minimally better' on the GRCS was 4 points.

CONCLUSIONS AND CLINICAL RELEVANCE

The VCDQ is a valid and responsive tool suitable for measuring changes in symptoms in patients with VCD. It also gives insight into which symptoms are important to patients and could guide future therapy refinements. Future assessments of novel therapies for this condition should use an appropriately validated tool such as the VCDQ to measure response.

Association between statins and clinical outcomes among men with prostate cancer: a systematic review and meta-analysis

BACKGROUND

Mixed evidence exists regarding the effects of statins among men with prostate cancer. We aimed to determine the association between statin use and clinical outcomes in prostate cancer using systematic review and meta-analysis.

METHODS

Original articles published until second week of August 2015 were searched in electronic databases (Medline-Ovid, Pubmed, Scopus, The Cochrane Library, Web of Science, ProQuest) for studies on statin use in prostate cancer. The main clinical outcomes for the review were: biochemical recurrence (BCR), metastases, and all-cause and prostate cancer-specific mortality. Meta-analysis was performed to calculate the pooled hazard ratio (pHR) and their 95% confidence interval (95% CI). Heterogeneity between the studies was examined using I(2) statistics. Meta-regression was performed, wherever significant heterogeneity was found in the meta-analyses, to find factors associated with poor outcomes, and sensitivity analyses were conducted to assess the robustness of findings. The analyses were conducted using RevMan v5.3, STATA v14, and R v3.1.1.

RESULTS

Out of the 1002 retrieved citations, 34 observational cohort studies met the inclusion criteria. Statin use was associated with a 21% reduction in the risk of BCR among those treated with radiation therapy (pHR: 0.79, 95% CI: 0.65, 0.95, P-value=0.01, 10 studies, I(2)=54%), whereas it was not associated with the BCR among those treated with radical prostatectomy (pHR: 0.94, 95% CI: 0.81, 1.09, P-value=0.43, 15 studies, I(2)=65%). Statin use was associated with a 22% reduction in the risk of metastases (pHR: 0.78, 95% CI: 0.68, 0.87, P-value<0.001, 6 studies, I(2)=0%), and a 24% reduction in risk of both all-cause mortality (pHR: 0.76, 95% CI: 0.63, 0.91, P-value=0.004, 6 studies, I(2)=71%), and prostate cancer-specific mortality (pHR: 0.76, 95% CI: 0.64, 0.89, P-value=0.0007, 5 studies, I(2)=40%).

CONCLUSIONS

Our systematic review found that statin significantly reduced the all-cause and prostate cancer-specific mortality and improved the BCR in certain subgroup of men with prostate cancer. In future, randomized controlled trials should be conducted to establish efficacy of statins among men with prostate cancer.

Impact of metformin on clinical outcomes among men with prostate cancer: a systematic review and meta-analysis

BACKGROUND

Conflicting evidence exists regarding the beneficial effects of metformin in prostate cancer. To determine the association between metformin and clinical outcomes in prostate cancer using systematic review and meta-analysis.

METHODS

Original articles published in English until third week of July, 2014 were searched in electronic databases (Medline-Ovid, Scopus, The Cochrane Library, Web of Science, ProQuest) for studies on metformin use in prostate cancer. The clinical outcomes assessed were: development of biochemical recurrence, metastases or castration-resistant metastatic cancer, all-cause and prostate cancer-specific mortality. Meta-analysis was performed to calculate the pooled hazard ratio (pHR) and their 95% confidence interval (95% CI). Heterogeneity between the studies was examined using I2 statistics. Sensitivity analysis was conducted to assess the robustness of findings and publication bias was assessed by the Egger's regression asymmetry test and contour plot.

RESULTS

Out of 230 retrieved citations, eight retrospective cohort studies and one nested-case-control study met the inclusion criteria. Metformin use was marginally associated with reduction in the risk of biochemical recurrence (pHR: 0.82, 95% CI: 0.67, 1.01, P-value=0.06, I2=25%, five studies). Metformin use was not significantly associated with metastases (pHR: 0.59, 95% 0.30-1.18, P-value=0.14, I2=74%, three studies), all-cause mortality (pHR: 0.86; 95% CI, 0.67, 1.10, P-value=0.23, I2: 73%, six studies) and prostate cancer-specific mortality (pHR: 0.76, 95% CI: 0.43, 1.33, P-value = 0.33, I2=60%, four studies). Pooled estimates for all outcomes varied in sensitivity analysis by diabetes status and primary treatment of prostate cancer. Systematic review revealed mixed findings on metformin use and the risk of CRPC.

CONCLUSIONS

Metformin may reduce the risk of biochemical recurrence in prostate cancer. Given the potential of selection bias in the observational studies, randomized trials should be designed to assess the efficacy of metformin use in prostate cancer.

Adult motor axons preferentially reinnervate predegenerated muscle nerve

Preferential motor reinnervation (PMR) is the tendency for motor axons regenerating after repair of mixed nerve to reinnervate muscle nerve and/or muscle rather than cutaneous nerve or skin. PMR may occur in response to the peripheral nerve pathway alone in juvenile rats (Brushart, 1993; Redett et al., 2005), yet the ability to identify and respond to specific pathway markers is reportedly lost in adults (Uschold et al., 2007). The experiments reported here evaluate the relative roles of pathway and end organ in the genesis of PMR in adult rats. Fresh and 2-week predegenerated femoral nerve grafts were transferred in correct or reversed alignment to replace the femoral nerves of previously unoperated Lewis rats. After 8 weeks of regeneration the motoneurons projecting through the grafts to recipient femoral cutaneous and muscle branches and their adjacent end organs were identified by retrograde labeling. Motoneuron counts were subjected to Poisson regression analysis to determine the relative roles of pathway and end organ identity in generating PMR. Transfer of fresh grafts did not result in PMR, whereas substantial PMR was observed when predegenerated grafts were used. Similarly, the pathway through which motoneurons reached the muscle had a significant impact on PMR when grafts were predegenerated, but not when they were fresh. Comparison of the relative roles of pathway and end organ in generating PMR revealed that neither could be shown to be more important than the other. These experiments demonstrate unequivocally that adult muscle nerve and cutaneous nerve differ in qualities that can be detected by regenerating adult motoneurons and that can modify their subsequent behavior. They also reveal that two weeks of Wallerian degeneration modify the environment in the graft from one that provides no modality-specific cues for motor neurons to one that actively promotes PMR.

Schwann cell phenotype is regulated by axon modality and central-peripheral location, and persists in vitro

Myelinating Schwann cells express distinct sensory and motor phenotypes as defined by their differing patterns of growth factor production (Hoke et al., 2006). The heterogeneous growth factor requirements of sensory and motor neurons, however, suggest that Schwann cell phenotype might vary across a broad spectrum. To explore this possibility, we selectively denervated six discrete Schwann cell populations: dorsal root, cutaneous nerve, cutaneous unmyelinated axons, muscle nerve afferents, muscle nerve efferents, and ventral root. Real-time RT-PCR for 11 growth factors was performed on the 6 target Schwann cell populations 5, 15, and 30 days after their denervation, and on normal cutaneous nerve, muscle nerve, ventral root, and dorsal root to establish baseline expression levels. Within the denervated axon populations, IGF-1 and VEGF were expressed most prominently in cutaneous nerve, HGF, NGF, and BDNF in cutaneous nerve and dorsal root, GDNF in dorsal root and ventral root, PTN in the ventral root and muscle nerve efferents, and IGF-2 in both afferents and efferents within muscle nerve; expression of CNTF, FGF-2 and NT-3 was not modality or location specific. ELISA for NGF, BDNF, and GDNF confirmed that gene expression correlated with protein concentration. These findings demonstrate that growth factor expression by denervated Schwann cells is not only subject to further regulation within the previously-defined sensory and motor groups, but also varies along a central-peripheral axis. The traditional view of myelinating Schwann cells as a homogenous population is modified by the realization that complex regulation produces a wide variety of Schwann cell phenotypes. Additionally, we found that Schwann cell phenotype is maintained for 2 weeks in vitro, demonstrating that it may survive several cell divisions without instructive cues from either axons or basal lamina.

Post chikungunya brain stem encephalitis

Chikungunya is an arthropod born acute febrile arbo viral illness characterized by acute severe polyarthralgia. During last few years there has been scattered out breaks with associated neurological complications in India. Here we report a case of post chikungunya reversible demyelinating encephalitis who presented with vertigo, dysarthria and ataxia. There was complete clinical as well as radiological improvement with steroids.