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Introduction: Glucosamine dietary supplements are commonly used for the management of osteoarthritis (OA). However, clinical trials have reported varying outcomes with regard to joint function and disease progression. One of the possible reasons for variability in observed effects of glucosamine could be that, unlike prescription drugs, the quality of manufactured dietary supplements is not closely monitored in many countries. Therefore, there is the possibility that the actual amount of glucosamine present in a dietary supplement is different from that claimed on the label. The quality control of glucosamine supplements is further complicated by the unavailability of a simple and effective analytical method for the analysis of glucosamine. Therefore, the aim of this study was to develop a simple analytical method that could be easily adapted by the pharmaceutical industry for routine analysis of glucosamine. Aims: To develop a novel high-performance liquid chromatography (HPLC) method for the quantification of glucosamine, and determine the amount of glucosamine present in a sample of dietary supplements commercially available in Australia and India. Methods: Chromatographic separation of glucosamine was achieved using a zwitter-ionic hydrophilic interaction liquid chromatography column with a mobile phase consisting of 60% acetonitrile and 40% of 85 mM ammonium acetate, at a flow rate of 0.3 mL/min and column temperature 40°C. The developed method was validated for intra- and inter-day linearity, accuracy, precision, and reproducibility. The newly-developed method was subsequently used to analyse 12 glucosamine supplements. Results: The developed method was selective for glucosamine, which had a retention time of 5.9 min. The standard curve was linear with a correlation coefficient (r2) exceeding 0.99, over the range of 10–200 μg/mL for glucosamine. The relative standard deviations for intra- and inter-day accuracy, precision and reproducibility were all less than 4%. The amount of glucosamine determined in six Australian and six Indian glucosamine supplements ranged between 98.7–101.7% and 85.9–101.8% of the labelled values, respectively. Discussion: Unlike previous HPLC methods, this newly-developed HPLC technique does not require pre-derivatisation and can separate glucosamine from both hydrochloride and sulphate salts, and from other amino sugars, such as chondroitin sulphate present in dietary supplements. This simple and effective technique can be employed by analytical laboratories for the quality control of glucosamine dietary supplements. Conclusion: The current study has developed a new analytical technique using HPLC-Corona CAD, which can analyse underivatised glucosamine hydrochloride and sulphate within 6 minutes. Using the novel assay, we confirmed that unlike the tested Australian dietary supplements, only half of the tested Indian products had a glucosamine content within ±10% of what was claimed on the label. [ABSTRACT FROM AUTHOR]

Modelling disease dynamics is most useful when data are limited. We present a spatial transmission model for the spread of canine rabies in the currently rabies-free wild dog population of Australia. The introduction of a sub-clinically infected dog from Indonesia is a distinct possibility, as is the spillover infection of wild dogs. Ranges for parameters were estimated from the literature and expert opinion, or set to span an order of magnitude. Rabies was judged to have spread spatially if a new infectious case appeared 120 km from the index case. We found 21% of initial value settings resulted in canine rabies spreading 120km, and on doing so at a median speed of 67 km/year. Parameters governing dog movements and behaviour, around which there is a paucity of knowledge, explained most of the variance in model outcomes. Dog density, especially when interactions with other parameters were included, explained some of the variance in whether rabies spread 120km, but dog demography (mean lifespan and mean replacement period) had minimal impact. These results provide a clear research direction if Australia is to improve its preparedness for rabies. [ABSTRACT FROM AUTHOR]

Despite many studies on the effects of heat on mental health, few studies have examined humidity. In order to investigate the relationship among heat, humidity and mental health, we matched data from the Social, Economic and Environmental Factors (SEEF) project with gridded daily temperature and water vapour pressure data from the Australian Bureau of Meteorology. Logit models were employed to describe the associations among heat (assessed using temperature, °C), humidity (assessed using vapour pressure, hPa) and two measures of mental health, (i) high or very high distress (assessed using K10 scores ≥ 22) and (ii) having been treated for depression or anxiety. We found a one-unit increase in temperature and vapour pressure was associated with an increase in the occurrence of high or very high distress by 0.2% (p < 0.001, 99% CI: 0.1–0.3%) and 0.1% (p < 0.001, 99% CI: 0.0–0.3%) respectively. However, when humidity rose to the 99th percentile of the sample, the estimated marginal effect of heat was more than doubled (0.5%, p < 0.001, 99% CI: 0.2–0.7%). Neither heat nor humidity was related to having been treated for depression or anxiety in the last month. Humidity compounds the negative association between hot weather and mental health and thus should be taken into account when reforming the health care system to respond to the challenge of climate change. [ABSTRACT FROM AUTHOR]