Cryo-EM structures of pannexin 1 and 3 reveal differences among pannexin isoforms.

Pannexins are single-membrane large-pore channels that release ions and ATP upon activation. Three isoforms of pannexins 1, 2, and 3, perform diverse cellular roles and differ in their pore lining residues. In this study, we report the cryo-EM structure of pannexin 3 at 3.9 Å and analyze its structural differences with pannexin isoforms 1 and 2. The pannexin 3 vestibule has two distinct chambers and a wider pore radius in comparison to pannexins 1 and 2. We further report two cryo-EM structures of pannexin 1, with pore substitutions W74R/R75D that mimic the pore lining residues of pannexin 2 and a germline mutant of pannexin 1, R217H at resolutions of 3.2 Å and 3.9 Å, respectively. Substitution of cationic residues in the vestibule of pannexin 1 results in reduced ATP interaction propensities to the channel. The germline mutant R217H in transmembrane helix 3 (TM3), leads to a partially constricted pore, reduced ATP interaction and weakened voltage sensitivity. The study compares the three pannexin isoform structures, the effects of substitutions of pore and vestibule-lining residues and allosteric effects of a pathological substitution on channel structure and function thereby enhancing our understanding of this vital group of ATP-release channels.

Control of post-harvest storage losses in water chestnut (Trapa bispinosa Roxburg) fruits by natural functional herbal coating and gamma radiation processing.

Water chestnut (Trapa bispinosa Roxburg) has short shelf life even after drying due to insect infestations resulting in huge economic losses to farmers. Study was performed including coating with Aloe-vera gel, air drying, LDPE packaging and gamma irradiation (≤ 1 kGy) were evaluated for their efficacy in controlling storage losses. The study was performed with complete randomized design up to 6-month storage period. Physico-chemical properties analysis indicated, weight loss (0.11-0.88%), damage (upto 6.5%) and lesser grain borer infestation (up to 16 no. per packet) during storage at different intervals. Moisture content ranged (9.25-10.10%), protein (8.82-8.89%), fat (0.90-1.00%), carbohydrate (76.83-76.89%), total ash (3.11-4.18%), total sugar (5.83-5.89%), reducing sugar (1.84-1.88%), non-reducing sugar (3.98-4.02%), amylose (66.54-66.64%), in-vitro starch digestibility (3.14-3.18%), phenolics (0.14-0.18%), acidity (0.11-0.12%) and ascorbic acid (41.66-50.00 mg/100 g). These treatments were not found to affect the quality attributes significantly however; it helps in controlling insect infestations at ambient condition. The sensory score of the product, 'Sev' was ranked as like slightly to moderately range. It could be concluded that water chestnut with combinations of 50% aloe-vera gel +0.75 kGy gamma radiation treatment could be stored up to 6 months with retention of quality attributes.

Dissection of Protonation Sites for Antibacterial Recognition and Transport in QacA, a Multi-Drug Efflux Transporter.

QacA is a drug:H+ antiporter with 14 transmembrane helices that confers antibacterial resistance to methicillin-resistant Staphylococcus aureus strains, with homologs in other pathogenic organisms. It is a highly promiscuous antiporter, capable of H+-driven efflux of a wide array of cationic antibacterial compounds and dyes. Our study, using a homology model of QacA, reveals a group of six protonatable residues in its vestibule. Systematic mutagenesis resulted in the identification of D34 (TM1), and a cluster of acidic residues in TM13 including E407 and D411 and D323 in TM10, as being crucial for substrate recognition and transport of monovalent and divalent cationic antibacterial compounds. The transport and binding properties of QacA and its mutants were explored using whole cells, inside-out vesicles, substrate-induced H+ release and microscale thermophoresis-based assays. The activity of purified QacA was also observed using proteoliposome-based substrate-induced H+ transport assay. Our results identify two sites, D34 and D411 as vital players in substrate recognition, while E407 facilitates substrate efflux as a protonation site. We also observe that E407 plays an additional role as a substrate recognition site for the transport of dequalinium, a divalent quaternary ammonium compound. These observations rationalize the promiscuity of QacA for diverse substrates. The study unravels the role of acidic residues in QacA with implications for substrate recognition, promiscuity and processive transport in multidrug efflux transporters, related to QacA.

An examination of traffic-related traumatic injuries among children at a Level-1 pediatric trauma center, 2005-2014.

BACKGROUND: Traffic-related injuries are the leading fatal injury among children in the United States, but no published study compares the different types of traffic-related pediatric injuries to date. Thus, this study was aimed at examining the10-year trend of traffic-related injury among children at a pediatric hospital and to assess if there were differences in injury mechanism. METHODS: All data were drawn from a Level-1 pediatric trauma center in North Texas in 2005-2014. Demographic characteristics, length of hospitalization, and patient type were included. Severity of injury outcome was assessed by injury severity score and fatality. The traffic-related injury mechanism included motor vehicle collision (MVC), motor-pedestrian collision (MPC), and motorcycle/moped collision (MMC). Description analyses and multinominal logistic regressions were applied to examine the factors associated with the type of motor-related injuries adjusting for covariates. All analyses were conducted by STATA version 14.0. RESULTS: A total of 3,742 traffic-related pediatric injuries were identified. The mean (SD) age was 6.4 (4.0) years; most patients were boys (59%) and Hispanic (40%). There was a waving trend of the number of traffic-related injuries over the 10-year period. Compared with MVC, demographic disparities exist with children experiencing an MPC injury. Hispanic and African American children were more likely to have an MPC but less likely to have a motorcycle/moped collision injury (relative risk [RR], 1.6; 95% confidence interval, 1.3-1.9; RR, 2.0; 95% confidence interval, 1.9-2.4, respectively). Children with an MPC injury had a more severe outcome than those with an MVC injury, but no difference was found in fatality. The MCC injuries did not significantly differ from MVC in injury severity. CONCLUSIONS: Although efforts have been made to prevent MVC-related pediatric injuries, the trend of MVCs was stable in the most recent years. The MPC-related injury continues to be a higher likelihood of severe pediatric trauma. Thus, continuing efforts and innovative intervention programs are still needed to prevent traffic-related pediatric injuries. LEVEL OF EVIDENCE: Epidemiologic study, level III.

An Unusual Case of Aortic Stenosis in Systemic Sclerosis.

Systemic sclerosis is a connective tissue disorder that frequently involves the heart. All cardiac structures can be involved but aortic valve involvement is rare. We report a case of an 83-year-old man with a history of systemic sclerosis presenting with shortness of breath. A transthoracic echocardiogram revealed severe aortic stenosis that could not be explained by other causes. These patients often pose challenges in management as they are not surgical candidates. Transaortic valvular implantation is a viable option for these patients.

An Unusual Case of Systemic Lupus Erythematosus and Hemophagocytic Syndrome.

Hemophagocytic syndrome (HS) or hemophagocytic lymphohistiocytosis (HLH) is an immune mediated phenomenon that can occur in the setting of an autoimmune disease, chronic immunosuppression, malignancy, or infection. It has been more commonly described in the pediatric population and less commonly in adults. We describe a case of a 52-year-old male who presented with a rash. He simultaneously met the Systemic Lupus International Collaborating Clinics (SLICC) criteria for the diagnosis of systemic lupus erythematosus (SLE) and the diagnostic criteria of HS as described in the hemophagocytic lymphohistiocytosis (HLH) 2004 trial. The bone marrow on autopsy showed the presence of abundant hemosiderophages with focal hemophagocytosis. SLE-associated HS might be underdiagnosed due to the overlap in clinical findings. This case represents the importance of prompt diagnosis and treatment of such a potentially fatal clinical syndrome.

A Case of Docetaxel Induced Myositis and Review of the Literature.

In phase I and II trials taxane chemotherapeutic agents reported side effects, including myelosuppression, peripheral edema, and fluid retention. With further use of these agents, studies in the late 1980s and early 1990s began to report peripheral neuropathy and proximal muscle weakness as common complaints, the later with unexplained pathophysiology. We report a 65-year-old Hispanic woman with estrogen receptor (ER) and progesterone receptor (PR) positive invasive ductal breast carcinoma who presented with right thigh pain and swelling eight days after her third infusion of docetaxel (a taxane chemotherapeutic) and cyclophosphamide. Laboratory findings were notable for elevation in creatine phosphokinase (CPK), aldolase, and erythrocyte sedimentation rate (ESR); a magnetic resonance imaging (MRI) of her lower extremities showed evidence of bilateral muscle edema involving the anterior compartment muscles of the thighs. A workup to rule out other causes of myositis was negative. Docetaxel was not reintroduced and the patient improved with corticosteroids. Since 2005 this is, to our knowledge, the fifth reported case of docetaxel related inflammatory myositis. Taxanes have been noted to cause disabling but transient arthralgias and myalgias; it is important to consider the possibility of inflammatory myopathy as a possible complication in patients undergoing treatment with these agents.

Waist circumference measurement by site, posture, respiratory phase, and meal time: implications for methodology.

Waist circumference (WC) has been advocated as a simple, reliable, and cost-effective measure to understand an individual's cardio-metabolic risk. Although several protocols exist for measuring WC, the variation induced by a few factors has not been investigated. We compared several established and experimental WC measurement protocols to identify factors that may cause variations in WC measurement. In this cross-sectional study, we examined the variations in the measurement of waist circumference (WC) measures carried out in 11 ways differing by anatomical site, posture, respiratory phase, and time since last meal, using repeated measure analysis of variance (using mixed models) after Tukey-Kramer adjustment. We estimated the proportion of variance in percentage of body fat (%BF) and fat-free mass (FFM) explained by each of the WC measures. We studied 123 apparently healthy Asian Indians (75 females), with mean (s.d.) age of 34 (8.7) years and BMI of 23.9 (4.8) kg/m(2). Overall, the mean of WCs measured using the 11 protocols were statistically different. Further, post hoc analysis showed statistically significant, yet mostly small, differences between most of the pairs. No single WC measure explained highest variance in %BF or FFM for both genders. Although, the National Institute of Health (NIH), USA, protocol was convenient and may be less prone to errors, at present it does not control for many variables tested in this study. Measures of WC measured using different protocols were statistically different. We suggest that the site of measurement, posture, phase of respiration, and time since last meal should be standardized for the development of a protocol for measurement of WC for worldwide use.

The biphasic transmittance waveform: an early marker of sepsis in patients with neutropenia.

Transmittance waveform (TW) analysis has been proposed as a method of both prediction and monitoring of non-overt and overt disseminated intravascular coagulation. This study assessed the use of the rapidTW of the activated partial thromboplastin time in the detection of sepsis in 49 consecutive neutropenic haemato-oncology patients. A slope 1 cut-off value of -0.050 was found to be optimum giving 85% sensitivity with 92% specificity and positive and negative predictive values of 62% and 98%, respectively. Furthermore a worsening slope 1 value at 24 hours was indicative of a 60% increase in mortality risk. Haemato-oncology patients have a significantly increased risk of developing sepsis during intensive chemotherapy, exacerbated by the resultant neutopenia. This sepsis may progress extremely rapidly and is associated with a high mortality. Early diagnosis is therefore critical and is currently made on a predominantly clinical basis with supporting microbiological evidence 2-3 days later. This study showed that TW offers an early marker, predictive of sepsis in neutropenic patients. It correlates with subsequent microbiological results and may identify patients at greater risk of clinical deterioration who may require more intensive early therapy or observation. It may also provide a useful marker to monitor the effects of treatment.