Adenosine, ‘pertussis-sensitive’ G-proteins, and K+ conductance in central mammalian neurones under energy deprivation

There is a striking similarity between the effects of adenosine and of hypoxia or glucose depletion on membrane potential and conductance of hippocampal neurones in tissue slices of rat brain. Both induce a membrane hyperpolarization by an increase in potassium conductance. It seemed likely, therefore, that a rise in extracellular adenosine concentration during energy deprivation may link neuronal metabolism with membrane K+ conductance. To test this hypothesis, we have now investigated the effects of hypoxia/glucose deprivation on hippocampal neurones from pertussis toxin-treated rats. In such slices adenosine had no effect on postsynaptic membrane potential and input resistance. Nevertheless, hypoxia or glucose depletion were as effective as in controls. These data provide evidence against adenosine as the main mediator between cell metabolism and potassium conductance

Health behaviours and health literacy: Hepatitis B regarding Sub-Saharan African migrants living in Queensland

Introduction: Hepatitis B Virus (HBV) is becoming an increasing health burden worldwide. Previous research indicates that lack of HBV awareness is a key contributing factor regarding individuals not engaging in preventative health behaviours, nor seeking medical treatment. A particular target group whom have higher rates of HBV are people from Culturally and Linguistically Diverse (CALD) backgrounds; including migrants from Sub-Saharan African (SSA) countries which are known to have higher rates of HBV infection. This study identified gaps in health literacy and HBV knowledge, and investigated how these factors influence related health behaviours among SSA migrants in Queensland. Methods: Cultural workers from a community organisation recruited 187 SSA migrant participants via ‘awareness stalls’ in Queensland. Participants answered self-report surveys regarding HBV knowledge, health literacy and health-protective behaviours; utilising quantitative cross-sectional surveys. The research also replicated previous methodology and compared findings to previous studies conducted with other cultural groups. Results: Preliminary findings indicated HBV knowledge significantly mediated health literacy and HBV screening. Health literacy (regarding self-efficacy) significantly predicted health behaviours (HBV screening, vaccinations). Participants with higher education and participants aged under 40 years of age, reported higher health literacy and engaged in more health-protective behaviours. Conclusions: Preliminary findings indicate significant associations between health-protective behaviours, HBV knowledge and health literacy. Greater awareness of the relationships between these constructs may assist in creating more informed prevention and health promotion strategies for identified target communities to reduce health disparities

Preserving Family: Themes from a Qualitative Study of Kin Caregivers

This article presents themes from a qualitative study of 58 African American female kinship caregivers in San Francisco. Core concepts that emerged describe various paths along which children move into kin homes, and caregivers\u27 mixed emotional reactions to becoming surrogate parents. Women also discussed multiple family roles they assumed after taking in children. Responses highlight three primary reasons for becoming caregivers that center on providing for and protecting these children—particularly from the perceived threat of the public foster care system—and ultimately preserving the family unit. Paradoxically, caregivers\u27 reasons mirror the stated goals of the public foster care system, which they view as a threat to family stability. We discuss the problems of implementing practice and policy recommendations for permanency and family preservation and how to bridge the gap between the deeply held negative beliefs of African American caregivers towards the public system and begin to build trust

A novel hybrid coagulation-constructed wetland system for the treatment of dairy wastewater

peer-reviewedConstructed wetlands (CWs) are a cost-effective and sustainable treatment technology that may be used on farms to treat dairy wastewater (DWW). However, CWs require a large area for optimal treatment and have poor long-term phosphorus removal. To overcome these limitations, this study uses a novel, pilot-scale coagulation-sedimentation process prior to loading CWs with DWW. This hybrid system, which was operated on an Irish farm over an entire milking season, performed well at higher hydraulic loading rates than conventional CWs, and obtained removal efficiencies ≥99 % for all measured water quality parameters (chemical oxygen demand, total nitrogen and phosphorus, total suspended solids and turbidity), which complied with EU directives concerning urban wastewater treatment. Overall, the hybrid coagulation-CW is a promising technology that requires a smaller area than conventional CWs and minimal operator input, and produces high effluent quality

Commensal bacteria augment Staphylococcus aureus infection by inactivation of phagocyte-derived reactive oxygen species

Staphylococcus aureus is a human commensal organism and opportunist pathogen, causing potentially fatal disease. The presence of non-pathogenic microflora or their components, at the point of infection, dramatically increases S. aureus pathogenicity, a process termed augmentation. Augmentation is associated with macrophage interaction but by a hitherto unknown mechanism. Here, we demonstrate a breadth of cross-kingdom microorganisms can augment S. aureus disease and that pathogenesis of Enterococcus faecalis can also be augmented. Co-administration of augmenting material also forms an efficacious vaccine model for S. aureus. In vitro, augmenting material protects S. aureus directly from reactive oxygen species (ROS), which correlates with in vivo studies where augmentation restores full virulence to the ROS-susceptible, attenuated mutant katA ahpC. At the cellular level, augmentation increases bacterial survival within macrophages via amelioration of ROS, leading to proliferation and escape. We have defined the molecular basis for augmentation that represents an important aspect of the initiation of infection

Differential timing of antibody-mediated phagocytosis and cell-free killing of invasive African Salmonella allows immune evasion

Nontyphoidal Salmonellae commonly cause fatal bacteraemia in African children lacking anti-Salmonella antibodies. These are facultative intracellular bacteria capable of cell-free and intracellular survival within macrophages. To better understand the relationship between extracellular and intracellular infection in blood and general mechanisms of Ab-related protection against Salmonella, we used human blood and sera to measure kinetics of Ab and complement deposition, serum-mediated bactericidal killing and phagocytosis of invasive African Salmonella enterica serovar Typhimurium D23580. Binding of antibodies peaked by 30 s, but C3 deposition lagged behind, peaking after 2-4 min. C5b-9 deposition was undetectable until between 2 and 6 min and peaked after 10 min, after which time an increase in serum-mediated killing occurred. In contrast, intracellular, opsonized Salmonellae were readily detectable within 5 min. By 10 min, around half of monocytes and most neutrophils contained bacteria. The same kinetics of serum-mediated killing and phagocytosis were observed with S. enterica Typhimurium laboratory strain SL1344, and the S. enterica Enteritidis African invasive isolate D24954 and laboratory strain PT4. The differential kinetics between cell-free killing and phagocytosis of invasive nontyphoidal Salmonella allows these bacteria to escape the blood and establish intracellular infection before they are killed by the membrane attack complex

Anaerobic removal of 1-methoxy-2-propanol under ambient temperature in an EGSB reactor

Two laboratory-scale expanded granular sludge bed (EGSB) reactors were operated at 18 and 25 C, respectively, for the treatment of synthetic wastewater composed of ethanol and 1-methoxy-2-propanol (M2P) in a mass ratio of 4:1. Reactors were operated first with continuous wastewater supply and after with discontinuous substrate supply (5 days a week, 16 h a day) to simulate shift working conditions. Under continuous wastewater supply chemical oxygen demand (COD), removal efficiency higher than 95 % was achieved at the end of the trial applying organic loading rates (OLR) of 29 and 43 kg COD m-3 day-1 at 18 and 25 C; thus, corresponding to M2P OLR of 6.4 and 9.3 kg COD m-3 day-1, respectively. During intermittent supply of substrate, good performance was recorded at both temperatures with an OLR of 30 kg COD m-3 day-1 (M2P OLR of 6.6 kg COD m-3 day-1). After 56 h without substrate supply, a decline in methane yield of 15¿30 % was observed due to the deactivation of the biomass. Specific methanogenic activity (SMA) assays were carried out at the end of the experiments. SMA values using 1-methoxy-2-propanol as substrate were 24.3 and 7.8 ml CH4 gVSS-1 day-1 at 25 C and at 18 C, respectively. This is the first attempt to investigate the removal of 1-methoxy-2-propanol by EGSB reactors