Calcium transients in single adrenal chromaffin cells detected with aequorin

AbstractThe effect of 55 mM K+ and nicotine on intracellular free calcium was monitored in bovine adrenal chromaffin cells microinjected with aequorin. In contrast to results with quin 2, which suggested that stimulation of chromaffin cells resulted in sustained rises in free calcium, aequorin measurements showed that 55 mM K+ and nicotine resulted in a transient (60–90 s) elevation of free calcium. The peak free calcium and duration of the transient elicited by nicotine were dose-dependent. The concentration of nicotine (10 μM) giving a maximal secretory response gave a peak rise in free calcium of up to 1 μM. 55 mM K+ which only releases 30% of the catecholamine released by 10 μM nicotine generated a calcium transient indistinguishable from that due to 10 μM nicotine. These results support the idea that nicotinic agonists generate an alternative second messenger in addition to the rise in free calcium

Prevalence of asthma and asthma action plans in South Australia: population surveys from 1990 to 2001

The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.OBJECTIVES: To assess trends in the prevalence of self-reported doctor-diagnosed asthma, associated asthma related morbidity, and the uptake of written asthma action plans in South Australia, 1990–2001. DESIGN, SETTING AND PARTICIPANTS: Surveys by telephone interview of the South Australian population between 1990 and 2001, and interview of participants in their own homes by trained health interviewers. MAIN OUTCOME MEASURES: Asthma prevalence, percentage of patients with written action plans, and asthma associated morbidity. RESULTS: The reported prevalence of doctor-diagnosed asthma has increased from 8% (95% CI, 6.4%–9.6%) in 1990 to 12.8% (95% CI, 11.4%–14.2%) in 2001. Morbidity, as measured by wakening at night (daily or weekly) and days lost from normal activities because of asthma, has remained constant over the decade. The percentage of patients with written asthma action plans increased to a peak of 42.3% (95% CI, 40.3%–44.3%) in 1995, but then declined to 22.2% (95% CI, 20.7%–23.7%) in 2001. CONCLUSIONS: The prevalence of asthma has increased while morbidity has remained constant, indicating that the burden of asthma has increased. The associated decline in the percentage of patients with asthma action plans in recent years is cause for concern.David H Wilson, Robert J Adams, Sarah L Appleton, Graeme Hugo, David Wilkinson, Janet Hiller, Philip Ryan, Julianne Cheek and Richard E Ruffi

Effects of Long-Term Hypoxia on Enzymes of Carbohydrate Metabolism in the Gulf killifish, Fundulus grandis

The goal of the current study was to generate a comprehensive, multi-tissue perspective of the effects of chronic hypoxic exposure on carbohydrate metabolism in the Gulf killifish Fundulus grandis. Fish were held at approximately 1.3·mg·l–1 dissolved oxygen (~3.6·kPa) for 4·weeks, after which maximal activities were measured for all glycolytic enzymes in four tissues (white skeletal muscle, liver, heart and brain), as well as for enzymes of glycogen metabolism (in muscle and liver) and gluconeogenesis (in liver). The specific activities of enzymes of glycolysis and glycogen metabolism were strongly suppressed by hypoxia in white skeletal muscle, which may reflect decreased energy demand in this tissue during chronic hypoxia. In contrast, several enzyme specific activities were higher in liver tissue after hypoxic exposure, suggesting increased capacity for carbohydrate metabolism. Hypoxic exposure affected fewer enzymes in heart and brain than in skeletal muscle and liver, and the changes were smaller in magnitude, perhaps due to preferential perfusion of heart and brain during hypoxia. The specific activities of some gluconeogenic enzymes increased in liver during long-term hypoxic exposure, which may be coupled to increased protein catabolism in skeletal muscle. These results demonstrate that when intact fish are subjected to prolonged hypoxia, enzyme activities respond in a tissue-specific fashion reflecting the balance of energetic demands, metabolic role and oxygen supply of particular tissues. Furthermore, within glycolysis, the effects of hypoxia varied among enzymes, rather than being uniformly distributed among pathway enzymes

Radiation‐Induced Oral Mucositis Hamster Model Using a Linear Accelerator Enhances Clinical Relevance of Preclinical Studies for Treatment Strategy Investigation

Translational animal models for oral mucositis (OM) are necessary to simulate and assess the bioclinical effects and response in humans. These models should simulate high levels of radiation exposure that leads to oxidative stress and inflammatory‐initiated tissue changes. Hamster models have been extensively studied to observe pathological effects of radiation exposure and help in the development of effective treatments. To successfully evaluate the potential for treatment regimens with consistency and relevance, a radiation‐induced OM hamster model was developed using a clinical linear accelerator utilized by cancer patients daily. The dose exposure to the isolated, everted cheek pouch of a hamster, as well as the progression of injury, pro‐inflammatory marker, histological, and elasticity analyses of the buccal pouch were conducted to verify replicability and reproducibility of the injury model. The findings from this model demonstrated its ability to consistently induce injury and resolution over 28 days using an acute dose of 60 Gy. This model was developed to enhance clinical relevance when evaluating potential efficacious treatments and can now be utilized in efficacy studies to better evaluate developed therapeutics in a preclinical model that is easy to translate to clinical studies

Direct evidence for the amorphous silicon phase in visible photoluminescent porous silicon

Article on direct evidence for the amorphous silicon phase in visible photoluminescent porous silicon

The north west Adelaide health study: detailed methods and baseline segmentation of a cohort for selected chronic diseases

The North West Adelaide Health Study is a population-based biomedical cohort study investigating the prevalence of a number of chronic conditions and health-related risk factors along a continuum. This methodology may assist with evidence-based decisions for health policy makers and planners, and inform health professionals who are involved in chronic disease prevention and management, by providing a better description of people at risk of developing or already diagnosed with selected chronic conditions for more accurate targeting groups for health gain and improved health outcomes. Longitudinal data will provide information on progression of chronic conditions and allow description of those who move forward and back along the continuum over time. Detailed methods are provided regarding the random recruitment and examination of a representative sample of participants (n = 4060), including the rationale for various processes and valuable lessons learnt. Self-reported and biomedical data were obtained on risk factors (smoking, alcohol consumption, physical activity, family history, body mass index, blood pressure, cholesterol) and chronic conditions (asthma, chronic obstructive pulmonary disease, diabetes) to classify participants according to their status along a continuum. Segmenting this population sample along a continuum showed that 71.5% had at least one risk factor for developing asthma, chronic obstructive pulmonary disease or diabetes. Almost one-fifth (18.8%) had been previously diagnosed with at least one of these chronic conditions, and an additional 3.9% had at least one of these conditions but had not been diagnosed. This paper provides a novel opportunity to examine how a cohort study was born. It presents detailed methodology behind the selection, recruitment and examination of a cohort and how participants with selected chronic conditions can be segmented along a continuum that may assist with health promotion and health services planning.Janet F Grant, Catherine R Chittleborough, Anne W Taylor, Eleonora Dal Grande, David H Wilson, Patrick J Phillips, Robert J Adams, Julianne Cheek, Kay Price, Tiffany Gill and Richard E Ruffi

Spatial Representations Are Specific to Different Domains of Knowledge

There is evidence that many abstract concepts are represented cognitively in a spatial format. However, it is unknown whether similar spatial processes are employed in different knowledge domains, or whether individuals exhibit similar spatial profiles within and across domains. This research investigated similarities in spatial representation in two knowledge domains – mathematics and music. Sixty-one adults completed analogous number magnitude and pitch discrimination tasks: the Spatial-Numerical Association of Response Codes and Spatial-Musical Association of Response Codes tasks. Subgroups of individuals with different response patterns were identified through cluster analyses. For both the mathematical and musical tasks, approximately half of the participants showed the expected spatial judgment effect when explicitly cued to focus on the spatial properties of the stimuli. Despite this, performances on the two tasks were largely independent. Consistent with previous research, the study provides evidence for the spatial representation of number and pitch in the majority of individuals. However, there was little evidence to support the claim that the same spatial representation processes underpin mathematical and musical judgments