The calcium channel β2 (CACNB2) subunit repertoire in teleosts

© 2008 Ebert et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Racial differences in the association between partner abuse and barriers to prenatal health care among asian and native Hawaiian/other Pacific Islander women

Objectives Prenatal health care (PNC) is associated with positive maternal and infant health outcomes. There is limited knowledge regarding Native Hawaiians/Other Pacific Islanders (NHOPI) and Asian women’s access to PNC especially among those with partner abuse (PA) experience. The objectives of this paper were to (1) describe and examine factors associated with PNC access barriers among mothers, by race; and, (2) determine the association between PA and PNC access, by race. Methods We analyzed 2004–2007 data from Hawai‘i’s Pregnancy Risk Assessment Monitoring System (n = 7,158). The outcome is ≥1 experience with a PNC access barrier. PA is experience with physical violence from a partner. Descriptive statistics, and bivariate and multivariate logistic regression analyses stratified by race were conducted. Results The respondents included 35.7% NHOPI, 37.4% Asian, 20.1% White and 6.6% Other. More than 6% experienced PA, and 25.9% reported ≥1 PNC access barrier. Experience with PA was significantly associated with NHOPI and Asians reporting ≥1 barrier to accessing PNC, but was non-significant with Whites. Conclusions Programs should address barriers to accessing PNC, and target NHOPI and Asian mothers with PA experience to reduce the healthcare disparity and improve quality of life

Orientation of the Calcium Channel β Relative to the α12.2 Subunit Is Critical for Its Regulation of Channel Activity

BACKGROUND: The Ca(v)beta subunits of high voltage-activated Ca(2+) channels control the trafficking and biophysical properties of the alpha(1) subunit. The Ca(v)beta-alpha(1) interaction site has been mapped by crystallographic studies. Nevertheless, how this interaction leads to channel regulation has not been determined. One hypothesis is that betas regulate channel gating by modulating movements of IS6. A key requirement for this direct-coupling model is that the linker connecting IS6 to the alpha-interaction domain (AID) be a rigid structure. METHODOLOGY/PRINCIPAL FINDINGS: The present study tests this hypothesis by altering the flexibility and orientation of this region in alpha(1)2.2, then testing for Ca(v)beta regulation using whole cell patch clamp electrophysiology. Flexibility was induced by replacement of the middle six amino acids of the IS6-AID linker with glycine (PG6). This mutation abolished beta2a and beta3 subunits ability to shift the voltage dependence of activation and inactivation, and the ability of beta2a to produce non-inactivating currents. Orientation of Ca(v)beta with respect to alpha(1)2.2 was altered by deletion of 1, 2, or 3 amino acids from the IS6-AID linker (Bdel1, Bdel2, Bdel3, respectively). Again, the ability of Ca(v)beta subunits to regulate these biophysical properties were totally abolished in the Bdel1 and Bdel3 mutants. Functional regulation by Ca(v)beta subunits was rescued in the Bdel2 mutant, indicating that this part of the linker forms beta-sheet. The orientation of beta with respect to alpha was confirmed by the bimolecular fluorescence complementation assay. CONCLUSIONS/SIGNIFICANCE: These results show that the orientation of the Ca(v)beta subunit relative to the alpha(1)2.2 subunit is critical, and suggests additional points of contact between these subunits are required for Ca(v)beta to regulate channel activity

Channelopathies in Cav1.1, Cav1.3, and Cav1.4 voltage-gated L-type Ca2+ channels

Voltage-gated Ca2+ channels couple membrane depolarization to Ca2+-dependent intracellular signaling events. This is achieved by mediating Ca2+ ion influx or by direct conformational coupling to intracellular Ca2+ release channels. The family of Cav1 channels, also termed L-type Ca2+ channels (LTCCs), is uniquely sensitive to organic Ca2+ channel blockers and expressed in many electrically excitable tissues. In this review, we summarize the role of LTCCs for human diseases caused by genetic Ca2+ channel defects (channelopathies). LTCC dysfunction can result from structural aberrations within their pore-forming α1 subunits causing hypokalemic periodic paralysis and malignant hyperthermia sensitivity (Cav1.1 α1), incomplete congenital stationary night blindness (CSNB2; Cav1.4 α1), and Timothy syndrome (Cav1.2 α1; reviewed separately in this issue). Cav1.3 α1 mutations have not been reported yet in humans, but channel loss of function would likely affect sinoatrial node function and hearing. Studies in mice revealed that LTCCs indirectly also contribute to neurological symptoms in Ca2+ channelopathies affecting non-LTCCs, such as Cav2.1 α1 in tottering mice. Ca2+ channelopathies provide exciting disease-related molecular detail that led to important novel insight not only into disease pathophysiology but also to mechanisms of channel function

Impacts of Poultry House Environment on Poultry Litter Bacterial Community Composition

Viral and bacterial pathogens are a significant economic concern to the US broiler industry and the ecological epicenter for poultry pathogens is the mixture of bedding material, chicken excrement and feathers that comprises the litter of a poultry house. This study used high-throughput sequencing to assess the richness and diversity of poultry litter bacterial communities, and to look for connections between these communities and the environmental characteristics of a poultry house including its history of gangrenous dermatitis (GD). Cluster analysis of 16S rRNA gene sequences revealed differences in the distribution of bacterial phylotypes between Wet and Dry litter samples and between houses. Wet litter contained greater diversity with 90% of total bacterial abundance occurring within the top 214 OTU clusters. In contrast, only 50 clusters accounted for 90% of Dry litter bacterial abundance. The sixth largest OTU cluster across all samples classified as an Arcobacter sp., an emerging human pathogen, occurring in only the Wet litter samples of a house with a modern evaporative cooling system. Ironically, the primary pathogenic clostridial and staphylococcal species associated with GD were not found in any house; however, there were thirteen 16S rRNA gene phylotypes of mostly Gram-positive phyla that were unique to GD-affected houses and primarily occurred in Wet litter samples. Overall, the poultry house environment appeared to substantially impact the composition of litter bacterial communities and may play a key role in the emergence of food-borne pathogens

THE EFFECT OF ACUTE AGMATINE SULFATE SUPPLEMENTATION ON REPEATED ANAEROBIC SPRINT PERFORMANCE

Cliff Helton, Luke Middleton, Justin Moody, Christopher G. Ballmann, FACSM, Tyler D. Williams, Rebecca R. Rogers. Samford University, Birmingham, AL. BACKGROUND: Agmatine sulfate is a commonly used ingredient in many pre-workout supplement blends that aim to improve physical performance and energy levels while exercising. However, the effect of isolated agmatine sulfate supplementation on anaerobic exercise performance is unknown. Therefore, the purpose of this study is to investigate the effect of acute agmatine sulfate supplementation on repeated anaerobic sprint performance. METHODS: Physically active, college-age males (21.8±0.5 yrs, 169.5±27.1 lbs, 69.0±5.0 in) were recruited into the study. The study was approved by the university Institutional Review Board. All participants completed a health history and informed consent. Participants visited our laboratory two times and completed three 15-second Wingate Anaerobic Cycling Tests (WAnT) at 7.5% of body weight after consuming either two 500 mg capsules of agmatine sulfate or two 500 mg placebo (corn starch) capsules 30 mins prior to exercise. There was a 2-minute recovery break between each WAnT. Blood lactate was measured before and after the 3x15 WAnT tests and rate of perceived exertion (RPE) was recorded. The agmatine sulfate and placebo trials were randomized and counterbalanced. Each visit was separated by a 72-hour washout period. RESULTS: Mean watts (p=0.44), peak watts (p=0.93), anaerobic capacity (p=0.42), anaerobic power (p=0.97), fatigue index (p=0.77), heart rate (p=0.31), blood lactate (p=0.40) and RPE (p=0.24) were averaged over the three repeated WAnTs and were not significantly different between the agmatine sulfate and placebo conditions. CONCLUSION: These findings do not support consuming one dose agmatine sulfate supplementation prior to exercise to improve anaerobic exercise performance or perceived exertion

Midwives' perceptions and experiences of routine enquiry for domestic violence.

OBJECTIVE: To examine midwives' perceptions and experiences of routine enquiry for domestic violence. DESIGN: Focus groups and semi-structured interviews. SETTING: The study was conducted in the maternity services of Guy's and St Thomas' NHS Hospital Trust, an inner London teaching hospital. SAMPLE: Twenty-eight midwives were interviewed. METHODS: One hundred and sixteen out of 145 (80%) midwives were trained to screen routinely pregnant women for domestic violence at booking, at 34 weeks of gestation and postpartum. Twenty midwives attended one of four focus groups and eight semi-structured interviews were conducted. Interviews were transcribed and analysed using content analysis. MAIN OUTCOME MEASURES: Midwives' views of routine enquiry for domestic violence. RESULTS: Midwives felt that domestic violence was an important issue to be addressed. However, practical and personal difficulties were encountered during the study. These included: time constraints, lack of confidential time, safety issues, staff shortages, low staff morale and midwives' personal experiences of domestic violence. The study produced a raised awareness about domestic violence within the maternity unit. There was considerable support for the idea of a specialist domestic violence midwife. CONCLUSIONS: Routine enquiry for domestic violence cannot be implemented effectively without ensuring that in-depth training, resources, staff support and policies to ensure that screening can be conducted safely and confidentially are in place