Fluorescence-Tracking of Activation Gating in Human ERG Channels Reveals Rapid S4 Movement and Slow Pore Opening

Background: hERG channels are physiologically important ion channels which mediate cardiac repolarization as a result of their unusual gating properties. These are very slow activation compared with other mammalian voltage-gated potassium channels, and extremely rapid inactivation. The mechanism of slow activation is not well understood and is investigated here using fluorescence as a direct measure of S4 movement and pore opening. Methods and Findings: Tetramethylrhodamine-5-maleimide (TMRM) fluorescence at E519 has been used to track S4 voltage sensor movement, and channel opening and closing in hERG channels. Endogenous cysteines (C445 and C449) in the S1–S2 linker bound TMRM, which caused a 10 mV hyperpolarization of the VK of activation to 227.562.0 mV, and showed voltage-dependent fluorescence signals. Substitution of S1–S2 linker cysteines with valines allowed unobstructed recording of S3–S4 linker E519C and L520C emission signals. Depolarization of E519C channels caused rapid initial fluorescence quenching, fit with a double Boltzmann relationship, F-VON, with VK,1 = 237.861.7 mV, and VK,2 = 43.567.9 mV. The first phase, VK,1, was,20 mV negative to the conductance-voltage relationship measured from ionic tail currents (G-VK = 218.361.2 mV), and relatively unchanged in a non-inactivating E519C:S620T mutant (V K = 234.461.5 mV), suggesting the fast initial fluorescence quenching tracked S4 voltage sensor movement. The second phase of rapid quenching was absent in the S620T mutant. The E519C fluorescence upon repolarizatio

Consensus statement on abusive head trauma in infants and young children

Abusive head trauma (AHT) is the leading cause of fatal head injuries in children younger than 2 years. A multidisciplinary team bases this diagnosis on history, physical examination, imaging and laboratory findings. Because the etiology of the injury is multifactorial (shaking, shaking and impact, impact, etc.) the current best and inclusive term is AHT. There is no controversy concerning the medical validity of the existence of AHT, with multiple components including subdural hematoma, intracranial and spinal changes, complex retinal hemorrhages, and rib and other fractures that are inconsistent with the provided mechanism of trauma. The workup must exclude medical diseases that can mimic AHT. However, the courtroom has become a forum for speculative theories that cannot be reconciled with generally accepted medical literature. There is no reliable medical evidence that the following processes are causative in the constellation of injuries of AHT: cerebral sinovenous thrombosis, hypoxic-ischemic injury, lumbar puncture or dysphagic choking/vomiting. There is no substantiation, at a time remote from birth, that an asymptomatic birth-related subdural hemorrhage can result in rebleeding and sudden collapse. Further, a diagnosis of AHT is a medical conclusion, not a legal determination of the intent of the perpetrator or a diagnosis of murder. We hope that this consensus document reduces confusion by recommending to judges and jurors the tools necessary to distinguish genuine evidence-based opinions of the relevant medical community from legal arguments or etiological speculations that are unwarranted by the clinical findings, medical evidence and evidence-based literature

Laparoscopic versus open sacrocolpopexy for treatment of prolapse of the apical segment of the vagina: a systematic review and meta-analysis

Introduction: Pelvic organ prolapse is showing an increasing prevalence (3 – 50 %). The gold standard treatment of apical prolapse is sacrocolpopexy which can be performed via minimal access (laparoscopy or robotics) or open approaches. The aim of this review was to appraise the effectiveness of minimal access surgery versus the open approach in the treatment of apical prolapse. Methods: Keywords were searched in: CINAHL, MEDLINE, CENTRAL, Cochrane MDSG Trials Register, Cochrane Library, Current Controlled Trials, ClinicalTrials.gov, WHO International Trials Registry Platform search portal, LILACS, and Google Scholar databases. Data up to 31 April 2014 were considered. Randomized and nonrandomized controlled trials evaluating all women who underwent minimally invasive sacropexy (MISC) and open sacropexy (OSC) were included. A data extraction tool was used for data collection. MISC was compared with OSC using narrative analysis and meta-analysis (RevMan) where appropriate. Results: MISC and OSC were compared in 12 studies involving 4,757 participants. MISC and OSC were equally effective in terms of point-C POP-Q measurements and recurrence rate. MISC was associated with a lower transfusion rate (odds ratio 0.41, 95 % CI 0.20 – 0.83), shorter length of hospital stay (mean difference −1.57 days, 95 % CI −1.91 – −1.23 days), and less blood loss (mean difference −113.27 mL, 95 % CI −163.67 – −62.87 mL) but a longer operating time (mean difference 87.47, 95 % CI 58.60 – 116.34, p < 0.0001). Conclusions: MISC showed similar anatomic results to OSC with a lower transfusion rate, shorter length of hospital stay and less blood loss. The rate of other complications was similar between the approaches. Cautious interpretation of results is advised due to risk of bias caused by the inclusion of nonrandomized studies

The effects of a novel "fluid loading" strategy on cardiovascular and haematological responses to orthostatic stress

Water drinking reduces the occurrence of syncope in healthy volunteers but the effects of hyperhydration are unknown. This study assessed the effects of combined creatine (Cr) and glycerol (Gly) induced hyperhydration on the cardiovascular and haematological responses to postural change. Subjects in all trials lay supine for 30 min before being tilted head-up to 70&#176; for a further 30 min or until the limit of their tolerance. Following 2 baseline trials, 19 subjects were matched for body mass and assigned to ingest either 20 g Cr and 2 g Gly kg-1 body mass (BM) plus 2 l of water or 2 l of water alone (Pl) each day for 6 days and once more 5 h prior to the experimental trial. Subjects ingested 500 ml of water prior to all trials to ensure euhydration. During baseline trials, 3 subjects in the Cr/Gly group and 2 in the Pl group experienced presyncope during head-up tilt. Following Cr/Gly supplementation, BM increased by (mean &#177; S.D.) 0.9 &#177; 0.3 and total body water (TBW) increased by 0.7 &#177; 0.2 l with no change in the Pl group. Cr/Gly supplementation resulted in a significant increase in systolic (11 mmHg) and diastolic (7 mmHg) blood pressure during head-up tilt with no change following Pl supplementation. Cr/Gly. Following Cr/Gly supplementation the number of subjects who became presyncopal was reduced from 3 to 1, with no change in the Pl group. These data suggest that hyperhydration mediated by Cr and Gly can enhance orthostatic tolerance in healthy individual