Voltage-gated proton channels exist in the plasma membrane of human oocytes

STUDY QUESTION

Do human oocytes express voltage-gated proton channels?

SUMMARY ANSWER

Human oocytes exhibit voltage-gated proton currents.

WHAT IS KNOWN ALREADY

Voltage-gated proton currents have been reported in human sperm, where they contribute to capacitation and motility. No such studies of human oocytes exist.

STUDY DESIGN, SIZE, DURATION

Voltage-clamp studies were undertaken using entire oocytes and vesicles derived from oocytes and in excised patches of membrane from oocytes.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Frozen, thawed human metaphase II oocytes were obtained from material donated to the gamete repository at the Rush Center for Advanced Reproductive Care. Prior to patch clamping, oocytes were warmed and equilibrated. Formation of an electrically tight seal requires exposing bare oolemma. Sections of the zona pellucida (ZP) were removed using a laser, followed by repeated pipetting, to further separate the oocyte from the ZP. Patch-clamp studies were performed using the whole-cell configuration on oocytes or vesicles derived from oocytes, and using inside-out patches of membrane, under conditions optimized to detect voltage-gated proton currents.

MAIN RESULTS AND THE ROLE OF CHANCE

Proton currents are present at significant levels in human oocytes where they exhibit properties similar to those reported in other human cells, as well as those in heterologous expression systems transfected with the HVCN1 gene that codes for the voltage-gated proton channel.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Human oocytes are large cells, which limits our ability to control the intracellular solution. Subtle effects of cryopreservation by vitrification and subsequent warming on properties of HVCN1, the HVCN1 gene product, cannot be ruled out.

WIDER IMPLICATIONS OF THE FINDINGS

Possible functions for voltage-gated proton channels in human oocytes may now be contemplated.

STUDY FUNDING/COMPETING INTEREST(S)

NIH R35GM126902 (TED), Bears Care (DM). No competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Stroke Mimics: A five-year follow-up study from the Qatar Stroke Database

BACKGROUND AND PURPOSE

Mimics comprise a third of patients presenting with an acute stroke. There is limited information on their natural history.

METHODS

We evaluate long term major cardiovascular events (MACE) in stroke mimics in a prospective database from Qatar.

RESULTS

Between Feb 2014 and Jan 2019, 481 patients (male: 238; female: 243) mean age 57.5 years (±18.0), with 399 (83%) medical mimics and 82 (17%) functional mimics were evaluated. Imaging revealed previous old stroke in 26.6% and small vessel disease in 5%. MACE occurred in 57 (11.9%) and there were 31 deaths (6.4%) with majority of deaths (5.6%) from cardiovascular causes. MACE was significantly higher in patients with previous stroke, p < 0.0001), coronary artery disease, p = 0.002), diabetic, p = 0.01), and hypertensive on admission, p < 0.0001. MACE were also significantly higher in patients where imaging showed a previous stroke, p = 0.006).

CONCLUSION

The occurrence of MACE during follow-up suggests that patients with existing vascular disease require aggressive management of vascular risk factors.

Sex-Specific Differences in Short-Term and Long-Term Outcomes in Acute Stroke Patients from Qatar

BACKGROUND

Sex differences may determine presentation, utility of treatment, rehabilitation, and occurrences of major adverse cardiovascular events (MACEs) in acute stroke (AS).

OBJECTIVE

The purpose of the study was to evaluate the short-term prognosis and long-term outcomes in MACEs in Qatari nationals admitted with AS.

METHODS

All AS patients admitted between January 2014 and February 2019 were included. We evaluated the preadmission modified Rankin scale (mRS) score, etiology and severity of symptoms, complications, and functional recovery at discharge and 90 days. MACEs were recorded for 5 years.

RESULTS

There were 891 admissions for AS (mean age 64.0 ± 14.2 years) (male, n = 519 [mean age ± SD 62.9 ± 14.1 years]; female, n = 372 [mean age ± SD 65.6 ± 14.2 years] p = 0.005). There were no differences in the preadmission mRS and severity of symptoms as measured on National Institute of Stroke Scale. At discharge, the outcome was better (mRS 0-2) in men (57.8 vs. 46.0%), p = 0.0001. This difference persisted at the 90-day follow-up (mRS 0-2, male 69.4% vs. female 53.2%, p = 0.0001). At the 90-day follow-up, more women died (total deaths 70; women 38 [10.2%] versus men 32 [6.2%], p = 0.03). MACEs occurred in 25.6% (133/519) males and 30.9% (115/372) females over the 5-year follow-up period (odds ratio 0.77, 95% confidence interval 0.57-1.0, p = 0.83).

CONCLUSIONS

Female patients have a poor short-term outcome following an AS when corrected for age and comorbidities. While our study cannot explain the reasons for the discrepancies, higher poststroke depression and social isolation in women may be important contributory factors, and requires further studies are required to confirm these findings.

Slowing improvements in life expectancy across European Economic Area countries

Background

Life expectancy improvements have slowed down in several European countries since around 2011. The relative contributions from changes in specific conditions (e.g. cancers) and broader risk factors (e.g. smoking or austerity) remain unclear. We aimed to explore the different potential causes in 17 European Economic Area (EEA) countries.

Methods

We compared Global Burden of Disease (GBD) study estimates for life expectancy, years of life lost (YLLs) and population attributable fractions (PAFs) for risk factors, for 2005-2011 and 2011-2017 for 17 EEA countries. Three countries with the largest absolute improvements and three with the smallest were selected for analysis by gender, age, condition and risk factors.

Results

Norway, France and Belgium had the largest improvement in life expectancy (+1.5, +1.2 and +1.2 years respectively) from 2011 to 2017, and Germany, Iceland and the UK the smallest (+0.1, +0.2 and +0.2 years). Life expectancy reduced slightly for women aged over 80 in Germany and UK, men aged over 50 in Germany, and for men in all age groups up to 90 years in Iceland. Norway, France and Belgium saw faster improvements in YLLs from lung cancer and Norway and France for COPD in both men and women, and from self-harm in men, after 2011 than before. PAF for tobacco declined faster after 2011. Germany, Iceland and the UK saw slower improvements in cardiovascular disease and in Germany and the UK lung cancer. In Iceland, YLLs for cancers, self harm, respiratory disease, cirrhosis and dementia all worsened after 2011. PAF for tobacco remained high or declined less after 2011 in all 3 countries. PAFs for alcohol and drug use remained high in Iceland and UK.

Conclusions

Differential changes in major fatal diseases and risk factors help explain national changes in life expectancies, but national differences in data availability may affect results. Further research is needed into the ‘causes of the causes’, such as the 2008 economic crash in Iceland.

Key messages

Differential changes in major fatal diseases and risk factors help explain national changes in life expectancies. Norway, France and Belgium had the largest improvement in life expectancy from 2011 to 2017, and Germany, Iceland and the UK the smallest.

Active immunization with tau epitope in a mouse model of tauopathy induced strong antibody response together with improvement in short memory and pSer396-tau pathology

Abnormal tau hyperphosphorylation and its aggregation into neurofibrillary tangles are a hallmark of tauopathies, neurodegenerative disorders that include Alzheimer's disease (AD). Active and passive Tau-immunotherapy has been proposed as a therapeutic approach to AD with mixed results. One of the limitations of active immunotherapy may be associated with the mediocre immunogenicity of vaccines that are not inducing therapeutically potent titers of antibodies. The aim of this study was to test the efficacy of an anti-tau vaccine, AV-1980R/A composed of N terminal peptide of this molecule fused with an immunogenic MultiTEP platform and formulated in a strong adjuvant, Advax^CpG in a Tg4510 mouse model of tauopathy. Experimental mice were immunized with AV-1980R/A and a control group of mice were injected with adjuvant only. Nontransgenic and tetracycline transactivator (tTA) transgenic littermates were included as baseline controls to contrast with the tau phenotype. Active immunization with AV-1980R/A induced very strong anti-tau humoral immune responses in both nontransgenic and transgenic mice with evidence of IgG in brains of AV-1980R/A vaccinated mice. These experimental animals displayed an improvement in short-term memory during a novel object recognition test. However, impairments in other behavioral tasks were not prevented by AV-1980R/A vaccinations. At the same time, high titers of anti-tau antibodies reduced hyperphosphorylated pSer396 tau but did not lower the level of other phosphorylated tau species in the brains of AV-1980R/A vaccinated mice. These data indicate that active immunotherapy with an N-terminal Tau epitope was only partially effective in improving cognition and reducing pathology in the stringent Tg4510 mouse model of tauopathy.

Surveillance of congenital Zika syndrome in England and Wales: methods and results of laboratory, obstetric and paediatric surveillance

The spread of the Zika virus (ZIKV) in the Americas led to large outbreaks across the region and most of the Southern hemisphere. Of greatest concern were complications following acute infection during pregnancy. At the beginning of the outbreak, the risk to unborn babies and their clinical presentation was unclear. This report describes the methods and results of the UK surveillance response to assess the risk of ZIKV to children born to returning travellers. Established surveillance systems operating within the UK - the paediatric and obstetric surveillance units for rare diseases, and national laboratory monitoring - enabled rapid assessment of this emerging public health threat. A combined total of 11 women experiencing adverse pregnancy outcomes after possible ZIKV exposure were reported by the three surveillance systems; five miscarriages, two intrauterine deaths and four children with clinical presentations potentially associated with ZIKV infection. Sixteen women were diagnosed with ZIKV during pregnancy in the UK. Amongst the offspring of these women, there was unequivocal laboratory evidence of infection in only one child. In the UK, the number and risk of congenital ZIKV infection for travellers returning from ZIKV-affected countries is very small.

Orthopaedic manifestations of pseudoachondroplasia

PURPOSE

In 1959, Maroteaux and Lamy initially designated pseudoachondroplasia as a distinct dysplasia different from achondroplasia the most common form of skeletal dysplasia. Pseudoachondroplasia is caused by a mutation in the collagen oligomeric matrix protein gene (COMP) gene on chromosome 19p13.1-p12 encoding the COMP. The COMP gene mutations result in rendering the articular and growth plate cartilages incapable of withstanding routine biomechanical loads with resultant deformity of the joints. The purpose of the study was to characterize the typical orthopaedic findings in pseudoachondroplasia.

METHODS

The charts and radiographs of 141 patients with pseudoachondroplasia were analyzed. This cohort, to our knowledge, represents the largest group of patients describing the typical orthopaedic manifestations of pseudoachondroplasia.

RESULTS

Patients with pseudoachondroplasia have normal craniofacial appearance with normal intelligence. Short stature is not present at birth and generally appears by two to four years of age. The condition is a form of spondyloepiphyseal dysplasia and the long bones are characterized by dysplastic changes in the epiphysis, metaphysis and vertebral bodies. Radiographically the long bones have altered the appearance and structure of the epiphyses with small irregularly formed or fragmented epiphyses or flattening. The metaphyseal regions of the long bones show flaring, widening or 'trumpeting'. The cervical (89%) and thoracic and lumbar vertebrae show either platyspondyly, ovoid, 'cod-fish' deformity or anterior 'beaking'. Kyphosis (28%), scoliosis (58%) and lumbar lordosis (100%) are commonly seen. The femoral head and acetabulum are severely dysplastic (100%). The knees show either genu valgum (22%), genu varum (56%) or 'windswept' deformity (22%).

CONCLUSION

Most commonly these distortions of the appendicular and the axial skeleton lead to premature arthritis particularly of the hips and often the knees not uncommonly in the 20- to 30-year-old age group.

LEVEL OF EVIDENCE

III.

Enhancing wastewater remediation by drinking water treatment residual-augmented floating treatment wetlands

In this study, the involvement of aluminum-based drinking water treatment residual (DWTR) as substrate in floating treatment wetland (FTW) to enhance its treatment performance was firstly proposed and trialed. A laboratory scale DWTR-FTW fed with synthetic wastewater containing COD, nitrogen (N), phosphorus (P) and mineral salts was operated in three stages of unplanted (1-30 days), planted (31-60 days) and aerated (61-135 days) modes. The results showed that the average removal rates of COD, total nitrogen (TN), total phosphorus (TP) in stage 3 were 88%, 85%, and 90.2%, respectively, indicating the outstanding purification performance of DWTR-FTW in comparison of traditional FTWs. The embedded DWTR enriches the biomass and robustly adsorbs P, while aeration supplies sufficient dissolved oxygen for the microorganism. The results revealed that 7.022 g P was accumulated in DWTR, which is 400 times higher than that in sediment and plants during the experimental period, reflecting that DWTR adsorption is the major P removal pathway in DWTR-FTW. Overall, DWTR-FTW could significantly remove pollutants, especially P, and provide an alternative pathway to enhance purification performance of FTW.

On the Elevated Temperature Thermal Stability of Nanoscale Mn-Ni-Si Precipitates Formed at Lower Temperature in Highly Irradiated Reactor Pressure Vessel Steels

Atom probe tomography (APT) and scanning transmission electron microscopy (STEM) techniques were used to probe the long-time thermal stability of nm-scale Mn-Ni-Si precipitates (MNSPs) formed in intermediate and high Ni reactor pressure vessel steels under high fluence neutron irradiation at ≈320 °C. Post irradiation annealing (PIA) at 425 °C for up to 57 weeks was used to determine if the MNSPs are: (a) non-equilibrium solute clusters formed and sustained by radiation induced segregation (RIS); or, (b) equilibrium G or Γ₂ phases, that precipitate at accelerated rates due to radiation enhanced diffusion (RED). Note the latter is consistent with both thermodynamic models and x-ray diffraction (XRD) measurements. Both the experimental and an independently calibrated cluster dynamics (CD) model results show that the stability of the MNSPs is very sensitive to the alloy Ni and, to a lesser extent, Mn content. Thus, a small fraction of the largest MNSPs in the high Ni steel persist, and begin to coarsen at long times. These results suggest that the MNSPs remain a stable phase, even at 105 °C higher than they formed at, thus are most certainly equilibrium phases at much lower service relevant temperatures of ≈290 °C.

Everolimus-induced osteonecrosis of the jaw in the absence of bisphosphonates: a case report

Osteonecrosis of the jaw (ONJ) is a rare, but severe, condition that has traditionally been associated with the use of bisphosphonates. We report what is, to our knowledge, the first case of ONJ secondary to the use of everolimus, in the absence of treatment with bisphosphonates in a 65-year-old man who was given it for immunosuppression after a renal transplant. After 18 months of treatment, he was diagnosed with severe ONJ and underwent radical debridement of the palate and complete dental clearance of the maxilla.

Establishing funding rates for colonoscopy and gastroscopy procedures in Ontario

Introduction

This paper describes the funding rates established in Ontario to reflect best practices in hospital-based care delivery for these endoscopic procedures: colonoscopy, colonoscopy biopsy, gastroscopy, gastroscopy biopsy, and colonoscopy combined with gastroscopy.

Methods

The funding rates are based on direct costs and were established using a micro-costing approach after receipt of inputs from 3 working groups and a review of the administrative data and literature, where applicable. The first group advised on nursing activities, time, and staffing ratios along the patient pathway for each of the procedures. The second group provided recommendations about the duration for each procedure, and the third group provided information about supplies and equipment, their use, and costs.

Results

The resulting funding rates are $161.18 for colonoscopy and $151.08 for gastroscopy (without accompanying interventions), $16.06 for colonoscopy biopsy and $8.22 for gastroscopy biopsy (added to the respective procedures), and $207.26 for combined colonoscopy and gastroscopy. Detailed costs for each component embedded in the rates are also provided.

Conclusions

The rates came into effect in April 2018. The process and outcomes described here allowed for a transparent pricing mechanism in which funding follows the patient, clinical expert consensus is the basis for practice, and providers and payers both understand the components.

Incidence, clinical features and outcomes of atrial fibrillation and stroke in Qatar

BACKGROUND

Atrial fibrillation is an important risk factor for stroke but there are limited data on atrial fibrillation-related stroke from the Middle East.

METHODS

We interrogated the Qatar Stroke Database to establish the occurrence, clinical features, and outcomes of atrial fibrillation-related stroke at Hamad General Hospital, the sole provider of acute stroke care in Qatar.

RESULTS

A total of 4079 patients (81.4% male, mean age 55.4 ± 13.3 years) were enrolled in the stroke database between January 2014 and 21 October 2017. Atrial fibrillation was present in 260 (6.4%) patients, of whom 106 (2.6%) had newly diagnosed atrial fibrillation. The National Institute of Health Stroke Scale (NIHSS) was significantly higher (7.9 + 7.0 (median 6; IQR 11) vs. 5.9 + 6.4 (median 4; IQR 6), P < 0.001) in atrial fibrillation patients. The modified Rankin Score (mRS) (P < 0.001) and mortality at 90-day follow-up (P = 0.002) were significantly higher in atrial fibrillation compared to non-atrial fibrillation stroke patients.

CONCLUSION

We demonstrate a low rate of atrial fibrillation and stroke in Qatar, perhaps reflecting the relatively young age of these patients. Atrial fibrillation-related strokes had higher admission NIHSS, greater disability, and higher mortality at 90 days when compared to non-atrial fibrillation strokes.