Biology subjects

Green, E.

Publications and source records attributed to Green, E..

3 recordsLinked to original sources

bioRxiv2018

Epidemiological impact of hepatitis B vaccination in Monastir Tunisia (2000-17)

Background: In 2016, the first global health sector strategy on viral hepatitis was endorsed with the goal of eliminating viral hepatitis as a public health threat by 2030. In Tunisia, effective vaccines for hepatitis B (HBV) have been added to the expanded programme of immunization (EPI) since July 1995 for new borns. We expected to have a decreasing trend in the prevalence rate of reported HBV. Our study aimed to address the epidemiological profile of HBV, to assess trends by age and gender in Monastir governorate over a period of 18 years according to immunization status and to estimate the burden (years lived with disability YLDs) of this pathology. Methods: We performed a descriptive cross sectional study of declared HBV from January 1, 2000 to December 31, 2017 defined as having positive serologic markers for HBs Ag. All declared patients were residents of Monastirs Governorate. EPI included two periods, the first between 1995 and 2006 following a three-dose schedule (3, 4, 9 months). The second PI cohort after 2006 following a three-dose schedule (0, 2, 6 months). Results: During 18 years, 1526 cases of HBV were declared in Monastir with a mean of 85 cases per year. We estimated a mean of 1699 declared cases per year of HBV in Tunisia. CPR was 16.85/100,000 inh being the higher in age group of 20-39 years and in men .ASR was 15.99/100,000 inh, being 35.5 in men and 8.69 in women. During the study period, declared cases among presumed immunized (PI) person against HBV were 32(2.0%). Among PI cases, 29 were from the first period and 3 were from the second. We established a negative trend over 18 years of hepatitis B. The age group of 20 to 39 was the most common with a sharply decline. Presumed not immunized (PNI) HBV cases are decreasing by years with a prediction of 35 cases in 2024. Reported HBV contributed to 1.26 YLDs per 100,000 inh. The highest rate of YLDs occurred at the age 20-39 (2.73 YLDs per 100,000 inh). During 18 years, YLDs were 114.45 in Monastir with a mean of 2293.65 YLDs of HBV in Tunisia. Conclusion, this study showed a law prevalence rate and a decreasing trend of HBV during 18 years showing an efficacy of immunization and confirming that the universal hepatitis B vaccination in Tunisia has resulted in progress towards the prevention and control of hepatitis B infection. These findings should be demonstrated in other Tunisian regions with a standardized serological profile.

immunology↗

bioRxiv2018

The structural basis for activation of voltage sensor domains in an ion channel TPC1

Voltage sensing domains (VSDs) couple changes in transmembrane electrical potential to conformational changes that regulate ion conductance through a central channel. Positively charged amino acids inside each sensor cooperatively respond to changes in voltage. Our previous structure of a TPC1 channel captured the first example of a resting-state VSD in an intact ion channel. To generate an activated state VSD in the same channel we removed the luminal inhibitory Ca2+-binding site (Cai2+), that shifts voltage-dependent opening to more negative voltage and activation at 0 mV. Cryo-EM reveals two coexisting structures of the VSD, an intermediate state 1 that partially closes access to the cytoplasmic side, but remains occluded on the luminal side and an intermediate activated state 2 in which the cytoplasmic solvent access to the gating charges closes, while luminal access partially opens. Activation can be thought of as moving a hydrophobic insulating region of the VSD from the external side, to an alternate grouping on the internal side. This effectively moves the gating charges from the inside potential to that of the outside. Activation also requires binding of Ca2+ to a cytoplasmic site (Caa2+). An X-ray structure with Caa2+ removed and a near-atomic resolution cryo-EM structure with Cai2+ removed define how dramatic conformational changes in the cytoplasmic domains may communicate with the VSD during activation. Together four structures provide a basis for understanding the voltage dependent transition from resting to activated state, the tuning of VSD by thermodynamic stability, and this channels requirement of cytoplasmic Ca2+-ions for activation.

biophysics↗

bioRxiv2017

TOWARDS A GLOBAL SUPPORT OF CORE DATA RESOURCES FOR THE LIFE SCIENCES

On November 18-19, 2016, the Human Frontier Science Program Organization (HFSPO) hosted a meeting of senior managers of key data resources and leaders of several major funding organizations to discuss the challenges associated with sustaining biological and biomedical (i.e., life sciences) data resources and associated infrastructure. A strong consensus emerged from the group that core data resources for the life sciences should be supported through a coordinated international effort(s) that better ensure long-term sustainability and that appropriately align funding with scientific impact. Ideally, funding for such data resources should allow for access at no charge, as is presently the usual (and preferred) mechanism. Below, the rationale for this vision is described, and some important considerations for developing a new international funding model to support core data resources for the life sciences are presented.

scientific communication and education↗