Antibiotic-Loaded Polymersomes for Clearance of Intracellular Burkholderia thailandensis

Melioidosis caused by the facultative intracellular pathogen Burkholderia pseudomallei is difficult to treat due to poor intracellular bioavailability of antibiotics and antibiotic resistance. In the absence of novel compounds, polymersome (PM) encapsulation may increase the efficacy of existing antibiotics and reduce antibiotic resistance by promoting targeted, infection-specific intracellular uptake. In this study, we developed PMs composed of widely available poly(ethylene oxide)-polycaprolactone block copolymers and demonstrated their delivery to intracellular B. thailandensis infection using multispectral imaging flow cytometry (IFC) and coherent anti-Stokes Raman scattering microscopy. Antibiotics were tightly sequestered in PMs and did not inhibit the growth of free-living B. thailandensis. However, on uptake of antibiotic-loaded PMs by infected macrophages, IFC demonstrated PM colocalization with intracellular B. thailandensis and a significant inhibition of their growth. We conclude that PMs are a viable approach for the targeted antibiotic treatment of persistent intracellular Burkholderia infection.

The treatment of melioidosis: is there a role for repurposed drugs? A proposal and review

Introduction: Melioidosis is a significant health problem within endemic areas such as Southeast Asia and Northern Australia. The varied presentation of melioidosis and the intrinsic antibiotic resistance of Burkholderia pseudomallei, the causative organism, make melioidosis a difficult infection to manage. Often prolonged courses of antibiotic treatments are required with no guarantee of clinical success.Areas covered: B. pseudomallei is able to enter phagocytic cells, affect immune function, and replicate, via manipulation of the caspase system. An examination of this mechanism, and a look at other factors in the pathogenesis of melioidosis, shows that there are multiple potential points of therapeutic intervention, some of which may be complementary. These include the directed use of antimicrobial compounds, blocking virulence mechanisms, balancing or modulating cytokine responses, and ameliorating sepsis.Expert commentary: There may be therapeutic options derived from drugs in clinical use for unrelated conditions that may have benefit in melioidosis. Key compounds of interest primarily affect the disequilibrium of the cytokine response, and further preclinical work is needed to explore the utility of this approach and encourage the clinical research needed to bring these into beneficial use.

Association between Body Mass Index and All-Cause Mortality among Oldest Old Chinese

OBJECTIVES

To examine the association between BMI and all-cause mortality in the oldest old (≥80 years).

DESIGN

The study used a prospective cohort study design.

SETTING

Chinese Longitudinal Healthy Longevity Survey (CLHLS) between 1998/99 and 2011.

POPULATION

8026 participants aged 80 years and older were followed every two to three years.

MEASUREMENTS

Body weight and knee height were measured. Height was calculated based on knee height using a validated equation. Deaths were ascertained from family members during follow-up.

RESULTS

The mean BMI was 19.8 (SD 4.5) kg/m2. The prevalence of underweight, overweight and obese was 37.5%, 10.2% and 4.4%, respectively. There were 5962 deaths during 29503 person-years of follow-up. Compared with normal weight, underweight was associated with a higher mortality risk (HRs: 1.20 (95%CI 1.13-1.27) but overweight (HR 0.89 (95%CI 0.81-0.99)) were associated with a lower risk. Obesity had a HR 0.91 (95%CI 0.78-1.05) for mortality.

CONCLUSION

Among oldest old Chinese, underweight is associated with an increased risk of all-cause mortality but overweight is associated with a reduced risk. Interventions to reduce undernutrition should be given priority among the oldest old Chinese.

Population levels of wellbeing and the association with social capital

Background

This research investigates wellbeing at the population level across demographic, social and health indicators and assesses the association between wellbeing and social capital.

Method

Data from a South Australian monthly chronic disease/risk factor surveillance system of randomly selected adults (mean age 48.7 years; range 16–99) from 2014/5 (n = 5551) were used. Univariable analyses compared wellbeing/social capital indicators, socio-demographic, risk factors and chronic conditions. Multi-nominal logistic regression modelling, adjusting for multiple covariates was used to simultaneously estimate odds ratios for good wellbeing (reference category) versus neither good nor poor, and good wellbeing versus poor wellbeing.

Results

48.6% were male, mean age 48.7 (sd 18.3), 54.3% scored well on all four of the wellbeing indicators, and positive social capital indicators ranged from 93.1% for safety to 50.8% for control over decisions. The higher level of social capital corresponded with the good wellbeing category. Modeling showed higher odds ratios for all social capital variables for the lowest level of wellbeing. These higher odds ratios remained after adjusting for confounders.

Conclusions

The relationship between wellbeing, resilience and social capital highlights areas for increased policy focus.

The role of business size in assessing the uptake of health promoting workplace initiatives in Australia

BACKGROUND

Worksite health promotion (WHP) initiatives are increasingly seen as having potential for large-scale health gains. While health insurance premiums are directly linked to workplaces in the USA, other countries with universal health coverage, have less incentive to implement WHP programs. Size of the business is an important consideration with small worksites less likely to implement WHP programs. The aim of this study was to identify key intervention points and to provide policy makers with evidence for targeted interventions.

METHODS

The worksites (n = 218) of randomly selected, working participants, aged between 30 and 65 years, in two South Australian cohort studies were surveyed to assess the practices, beliefs, and attitudes regarding WHP. A survey was sent electronically or by mail to management within each business.

RESULTS

Smaller businesses (<20 employees) had less current health promotion activies (mean 1.0) compared to medium size businesses (20-200 employees - mean 2.4) and large businesses (200+ employees - mean 2.9). Management in small businesses were less likely (31.0 %) to believe that health promotion belonged in the workplace (compared to 55.7 % of medium businesses and 73.9 % of large businesses) although half of small businesses did not know or were undecided (compared to 36.4 and 21.6 % of medium and large businesses). In total, 85.0 % of smaller businesses believed the health promotion activities currently employed in the worksite were effective (compared to 89.2 % of medium businesses and 83.1 % of large businesses). Time and funding were the most cited responses to the challenges to implementing health promoting strategies regardless of business size. Small businesses ranked morale and work/life balance the highest among a range of health promotion activities that were important for their workplace while work-related injury was the highest ranked consideration for large businesses.

CONCLUSION

This study found that smaller workplaces had many barriers, beliefs and challenges regarding WHP. Often small businesses find health promotion activities a luxury and not a serious focus of their activities although this study found that once a health promoting strategy was employed, the perceived effectiveness of the activities were high for all business regardless of size. Tailored low-cost programs, tax incentives, re-orientation of work practices and management support are required so that the proportion of small businesses that have WHP initiatives is increased.

Retinal Pigment Epithelial Cell Line Suppression of Phagolysosome Activation

The eye is an immune privileged tissue with multiple mechanisms of immunosuppression to protect the light gathering tissues from the damage of inflammation. One of theses mechanisms involves retinal pigment epithelial cell suppression of phagosome activation in macrophages. The objective of this work is to determine if the human RPE cell line ARPE-19 is capable of suppressing the activation of the phagolysosome in macrophages in a manner similar to primary RPE. The conditioned media of RPE eyecups, sub-confluent, just confluent cultures, or established confluent cultures of human ARPE-19 cells were generated. These condition media were used to treat macrophages phagocytizing pHrodo bioparticles. After 24 hours incubation the macrophages were imaged by fluorescent microscopy, and fluorescence was measured. The fluorescent intensity is proportional to the amount of bioparticles phagocytized and are in an activated phagolysosome. The conditioned media of in situ mouse RPE eyecups significantly suppressed the activation of phagolysosome. The conditioned media from cultures of human ARPE-19 cells, grown to sub-confluence (50%) or grown to confluence had no effect on phagolysosome activation. In contrast, the conditioned media from established confluent cultures significantly suppressed phagolysosome activation. The neuropeptides alpha-MSH and NPY were depleted from the conditioned media of established confluent ARPE-19 cell cultures. This depleted conditioned media had diminished suppression of phagolysosome activation while promoting macrophage cell death. In addition, the condition media from cultures of ARPE-19 monolayers wounded with a bisecting scrape was diminished in suppressing phagolysosome activation. This technical report suggests that like primary RPE monolayers, established confluent cultures of ARPE-19 cells produce soluble factors that suppress the activation of macrophages, and can be used to study the molecular mechanisms of retinal immunobiology. In addition, the results further demonstrate the importance of an intact monolayer of RPE cells to modulate immune cell activity within the eye.

Ex-vivo tolerogenic F4/80⁺ antigen-presenting cells (APC) induce efferent CD8⁺ regulatory T cell-dependent suppression of experimental autoimmune uveitis

It is known that inoculation of antigen into the anterior chamber (a.c.) of a mouse eye induces a.c.-associated immune deviation (ACAID), which is mediated in part by antigen-specific local and peripheral tolerance to the inciting antigen. ACAID can also be induced in vivo by intravenous (i.v.) inoculation of ex-vivo-generated tolerogenic antigen-presenting cells (TolAPC). The purpose of this study was to test if in-vitro-generated retinal antigen-pulsed TolAPC suppressed established experimental autoimmune uveitis (EAU). Retinal antigen-pulsed TolAPC were injected i.v. into mice 7 days post-induction of EAU. We observed that retinal antigen-pulsed TolAPC suppressed the incidence and severity of the clinical expression of EAU and reduced the expression of associated inflammatory cytokines. Moreover, extract of whole retina efficiently replaced interphotoreceptor retinoid-binding protein (IRBP) in the preparation of TolAPC used to induce tolerance in EAU mice. Finally, the suppression of EAU could be transferred to a new set of EAU mice with CD8⁺ but not with CD4⁺regulatory T cells (T_reg). Retinal antigen-pulsed TolAPC suppressed ongoing EAU by inducing CD8⁺ T_reg cells that, in turn, suppressed the effector activity of the IRBP-specific T cells and altered the clinical symptoms of autoimmune inflammation in the eye. The ability to use retinal extract for the antigen raises the possibility that retinal extract could be used to produce autologous TolAPC and then used as therapy in human uveitis.

The redox-associated adaptive response of brain to physical exercise

Reactive oxygen species (ROS) are continuously generated during metabolism. ROS are involved in redox signaling, but in significant concentrations they can greatly elevate oxidative damage leading to neurodegeneration. Because of the enhanced sensitivity of brain to ROS, it is especially important to maintain a normal redox state in brain and spinal cord cell types. The complex effects of exercise benefit brain function, including functional enhancement as well as its preventive and therapeutic roles. Exercise can induce neurogenesis via neurotrophic factors, increase capillarization, decrease oxidative damage, and enhance repair of oxidative damage. Exercise is also effective in attenuating age-associated loss in brain function, which suggests that physical activity-related complex metabolic and redox changes are important for a healthy neural system.

Osteoporosis in the community: Sensitivity of self-reported estimates and medication use of those diagnosed with the condition

Objectives

To assess the sensitivity and specificity of self-reported osteoporosis compared with dual energy X-ray absorptiometry (DXA) defined osteoporosis, and to describe medication use among participants with the condition.

Methods

Data were obtained from a population-based longitudinal study and assessed for the prevalence of osteoporosis, falls, fractures and medication use. DXA scans were also undertaken.

Results

Overall 3.8% (95% confidence interval (CI) 3.2 to 4.5) of respondents and 8.8% (95% CI 7.5 to 10.3) of those aged ≥ 50 years reported that they had been diagnosed with osteoporosis by a doctor. The sensitivity (those self-reporting osteoporosis and having low bone mineral density (BMD) on DXA) was low (22.7%), although the specificity was high (94.4%). Only 16.1% of those aged ≥ 50 years and with DXA-defined osteoporosis were taking bisphosphonates.

Conclusions

The sensitivity of self-reporting to identify osteoporosis is low. Anti-osteoporotic medications are an important part of osteoporosis treatment but opportunities to use appropriate medications were missed and inappropriate medications were used.

Proximal correlates of metabolic phenotypes during 'at-risk' and 'case' stages of the metabolic disease continuum

OBJECTIVE

To examine the social and behavioural correlates of metabolic phenotypes during 'at-risk' and 'case' stages of the metabolic disease continuum.

DESIGN

Cross-sectional study of a random population sample.

PARTICIPANTS

A total of 718 community-dwelling adults (57% female), aged 18-92 years from a regional South Australian city.

MEASUREMENTS

Total body fat and lean mass and abdominal fat mass were assessed by dual energy x-ray absorptiometry. Fasting venous blood was collected in the morning for assessment of glycated haemoglobin, plasma glucose, serum triglycerides, cholesterol lipoproteins and insulin. Seated blood pressure (BP) was measured. Physical activity and smoking, alcohol and diet (96-item food frequency), sleep duration and frequency of sleep disordered breathing (SDB) symptoms, and family history of cardiometabolic disease, education, lifetime occupation and household income were assessed by questionnaire. Current medications were determined by clinical inventory.

RESULTS

36.5% were pharmacologically managed for a metabolic risk factor or had known diabetes ('cases'), otherwise were classified as the 'at-risk' population. In both 'at-risk' and 'cases', four major metabolic phenotypes were identified using principal components analysis that explained over 77% of the metabolic variance between people: fat mass/insulinemia (FMI); BP; lipidaemia/lean mass (LLM) and glycaemia (GLY). The BP phenotype was uncorrelated with other phenotypes in 'cases', whereas all phenotypes were inter-correlated in the 'at-risk'. Over and above other socioeconomic and behavioural factors, medications were the dominant correlates of all phenotypes in 'cases' and SDB symptom frequency was most strongly associated with FMI, LLM and GLY phenotypes in the 'at-risk'.

CONCLUSION

Previous research has shown FMI, LLM and GLY phenotypes to be most strongly predictive of diabetes development. Reducing SDB symptom frequency and optimising the duration of sleep may be important concomitant interventions to standard diabetes risk reduction interventions. Prospective studies are required to examine this hypothesis.

Hormone therapy use after the Women's Health Initiative

OBJECTIVE

To continue surveillance of hormone therapy (HT) use in an Australian population and to assess the impact of the Women's Health Initiative (WHI) and associated reports on HT use 16 months after the results of the WHI were first reported.

METHODS

Data were obtained from the 2003 South Australian Health Omnibus Survey, which involves a representative, population face-to-face interview survey. Data were compared to five surveys undertaken between 1991 and 2000, which had consistent methods and quality-control procedures. A total of 907 interviews were conducted with women over 40 years in their own homes by trained health interviewers.

RESULTS

In association with the timing of media reporting of the WHI, current HT use rates dropped from 28% in women over 50 years in 2000 to an estimated 10.2% in 2002. By October 2003, current use rates had returned to 18.8% in this age group. The media had been the main influence in the women's decision-making. Half of those who restarted therapy changed to another type of HT. Only 2.8% changed to an alternative/complementary therapy.

CONCLUSIONS

Nearly two-thirds (64%) of those currently using HT in 2002 stopped therapy, mostly in response to the media reporting of the WHI. Nearly half of those who stopped HT in 2002 have since restarted. Media reporting greatly influences the use of hormonal therapies.

Continuing decline in hormone therapy use: population trends over 17 years

OBJECTIVE

To describe the prevalence of menopausal hormone therapy (HT) in 2008 and trends over the last 17 years in an Australian population.

METHODS

Data were obtained from nine representative population face-to-face interview surveys of the South Australian population from 1991 to 2008. The surveys used consistent method and quality control procedures. In 2008, demographic data, HT use and eight dimensions of health, using the SF-36 health survey questionnaire, were measured. Participants Over 3000 South Australian adults were interviewed in their own home by trained health interviewers in each of the surveys; in the 2008 survey, 1555 women participated, of whom 953 were over age 40.

RESULTS

After a peak in use in the 2000 survey, HT use fell from 2003 and has continued to decline in 2008. In 2008, current use over age 50 of registered conventional HT products is now 11.8%, with a further 4.0% using non-registered alternative 'hormonal' products. Current HT use is highest between the ages of 50 and 59 years, where 13.4% use conventional HT and 7.7% use unconventional alternative hormones. Use of these unregistered hormonal products was rare in previous surveys. Median and mean length of conventional HT use were 10.0 and 10.5 years, respectively. HT users continued to have a demographic profile similar to those in previous surveys, i.e. they were better educated, employed, partnered, had a higher income and were less inclined to use complementary and alternative medicines.

CONCLUSIONS

There has been a continuing decline in both the overall prevalence and length of use of conventional HT from 2003, probably in association with negative media about HT. Of medical concern is that about one-quarter of women using HT around menopause now chooses unregistered hormonal mixtures that are untested for long-term safety and efficacy.

Injection of an alpha-melanocyte stimulating hormone expression plasmid is effective in suppressing experimental autoimmune uveitis

PURPOSE

The neuropeptide, alpha-melanocyte stimulating hormone (alpha-MSH), is an endogenous antagonist of inflammation. Injections of alpha-MSH peptide into inflamed tissues have been found to be very effective in suppressing autoimmune and endotoxin mediated diseases. We evaluated the potential to suppress ocular autoimmune disease (uveitis) by augmenting the expression of alpha-MSH through subconjunctival injections of naked adrenocorticotropic hormone amino acids 1-17 (ACTH1-17) plasmid.

METHODS

We clinically scored the uveitis over time in B10.RIII, C57BL/6, and melanocortin 5 receptor knock-out (MC5r((-/-))) mice with experimental autoimmune uveitis (EAU) that were conjunctively injected with a naked DNA plasmid encoding ACTH1-17 at the time of EAU onset and three days later. The post-EAU retina histology of plasmid injected eyes was examined, and post-EAU concentrations of alpha-MSH in aqueous humor was assayed by ELISA.

RESULTS

The subconjunctival injection of ACTH1-17 plasmid augmented the concentration of alpha-MSH in the aqueous humor of all post-EAU mice. The injection of ACTH1-17 suppressed the severity of EAU in the B10.RIII and C57BL/6 mice but the MC5r((-/-)) mice. In all the models of EAU, the ACTH1-17 injection helped to preserve the structural integrity of the retina; however, post-EAU aqueous humor was not immunosuppressive.

CONCLUSIONS

The subconjunctival injection of the alpha-MSH expression vector ACTH1-17 plasmid is effective in suppressing EAU. The suppressive activity is dependent on MC5r expression, and possibly works though alpha-MSH antagonism of inflammation than on alpha-MSH directly modulating immune cells. The results suggest that an effective therapy for uveitis could include a gene therapy approach based on delivering alpha-MSH.

Ocular immune privilege

It has been over 60 years since the phrase immune privilege was used by Sir Peter Medawar to describe the lack of an immune response against allografts placed into the ocular microenvironment. Since then, we have come to understand that the mechanisms of ocular immune privilege include unique anatomical features of a blood barrier and a lack of direct lymphatic drainage. Also, we know that the ocular microenvironment is rich with immunosuppressive molecules that influence the activity of immune cells. Moreover, the placement of foreign antigen into the ocular microenvironment can induce a systemic form of tolerance to the foreign antigen called anterior chamber-associated immune deviation (ACAID). Many soluble immunomodulators are found in aqueous humour, and are a mixture of growth factors, cytokines, neuropeptides, and soluble receptors. This is a continuously growing list. The mechanisms of ocular immune privilege induce apoptosis, promote the production of anti-inflammatory cytokines, and mediate the activation of antigen-specific regulatory immunity. These mechanisms of immune privilege also attempt to impose themselves upon immunity within the uveitic eye. The adaptation of several anatomical and biochemical mechanisms to establish an immune privileged microenvironment within the eye makes the eye immunologically unique. It is a tissue site where we may learn how immunity is regulated in inflammation and at rest. Success in translating the lessons of ocular immune privilege to other tissues has the potential to drastically change the therapy and clinical outcomes of autoimmune diseases and allograft survival.

The increasing prevalence of diabetes in South Australia: The relationship with population ageing and obesity

OBJECTIVES

To use representative population surveillance data to monitor and project changes in the prevalence of diabetes for different age and body mass index (BMI) groups.

STUDY DESIGN

Representative, annual, face-to-face South Australian Health Omnibus Surveys, 1991-2003 (n=3000 per year).

METHODS

Trends in self-reported diabetes prevalence by age group and BMI were examined. Separate projections were made on the basis of predicted changes in population demography and diabetes prevalence.

RESULTS

The age-sex standardized absolute prevalence of self-reported diabetes among people aged 15 years and over increased from 3.5% in 1991 to 6.7% in 2003. If this current trend continues, the prevalence is expected to increase to 10.5% by 2016. The prevalence of diabetes was significantly higher among those classified as obese (6.5% in 1991 to 12.2% in 2003) than those with normal BMI. The greatest relative percentage increase in prevalence between 1991 and 2003 (169%) was seen among people aged 15-39 years. Taking both age group and BMI classification into account, the greatest relative percentage increases over this time were seen among those with normal BMI aged 60 years or older (148%), and those who were obese and aged less than 60 years (139%).

CONCLUSIONS

The prevalence of diabetes and obesity increased significantly between 1991 and 2003. Population ageing and an increase in diabetes prevalence in the future will further increase the burden of diabetes. Future increases in diabetes prevalence are not inevitable, however, if investments are made in public health prevention programmes, particularly those addressing obesity.

A life-course approach to measuring socioeconomic position in population health surveillance systems

Measuring socioeconomic position (SEP) in population chronic disease and risk factor surveillance systems is essential for monitoring socioeconomic inequalities in health over time. Life-course measures are an innovative way to supplement other SEP indicators in surveillance systems. A literature review examined the indicators of early-life SEP that could potentially be used in population health surveillance systems. The criteria of validity, relevance, reliability and deconstruction were used to determine the value of potential indicators. Early-life SEP indicators used in cross-sectional and longitudinal studies included education level, income, occupation, living conditions, family structure and residential mobility. Indicators of early-life SEP should be used in routine population health surveillance to monitor trends in the health and SEP of populations over time, and to analyse long-term effects of policies on the changing health of populations. However, these indicators need to be feasible to measure retrospectively, and relevant to the historical, geographical and sociocultural context in which the surveillance system is operating.

Melanocortin 5 receptor and ocular immunity

The nervous system contributes to the mechanisms of ocular immune privilege by the constitutive presence of the immunosuppressive neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH) in the eye. Alpha-MSH through the melanocortin 5 receptor (MC5r) mediates induction of CD4+ regulatory T cells that suppress in an antigen specific manner autoimmune disease. We investigated whether there was a role for MC5r expression in ocular immunity and the natural induction of regulatory T cells that emerged following resolution of experimental autoimmune uveoretinitis (EAU). Unlike wild type mice, EAU in MC5r-/- mice caused severe retinal damage, did mice expressed a not induce the emergence of ocular autoantigen regulatory immunity in the spleen, and the MC5r-/- classical memory immune response when reimmunized with ocular autoantigen. There was expression of MC5r in retinal pigment epithelial cells, in the ganglion cell and neural outer plexiform layers of healthy wild type mice retinas. The recovery of the ocular microenvironment from EAU was not dependent on the expression of MC5r, nor was the recovery dependent on the induction of CD4+ regulatory T cells (Treg cells) in the spleen. However, protection of the retina from the inflammatory damage of EAU and the induction of ocular autoantigen-responsive CD4+ Treg cells in the post EAU spleen requires expression of MC5r.

The immunomodulating neuropeptide alpha-melanocyte-stimulating hormone (alpha-MSH) suppresses LPS-stimulated TLR4 with IRAK-M in macrophages

Since alpha-MSH suppresses endotoxin-induced inflammation by innate immunity, it is possible that alpha-MSH can suppress the interface between innate and adaptive immunity mediated by TLR4-stimulated macrophages. Endotoxin-stimulated macrophages treated with alpha-MSH are suppressed in nitric oxide and IL-12p70 production, and cannot enhance antigen-stimulated IFN-gamma production by Th1 cells. In macrophages treated with alpha-MSH, the inhibitory molecule IRAK-M is bound to IRAK-1, the proximal intracellular signal molecule of endotoxin-bound TLR4. These results further demonstrate the dynamic contribution of the nervous system, and the role of alpha-MSH in modulating the innate and adaptive immune interface in an inflammatory response.

Psychological factors and asthma quality of life: a population based study

BACKGROUND

Reports of psychological conditions in asthmatic subjects have been limited to certain population groups or convenience samples. A study was undertaken of the prevalence of psychological distress in asthma in the general population and its associations with quality of life.

METHODS

The WANTS Health and Well-being Survey is a population household interview survey of adults (age > or =18) in Western Australia, the Northern Territory, and South Australia. Data obtained were weighted to the closest census data to provide population representative estimates. Positive answers to two questions: "Have you ever been told by a doctor that you have asthma?" and "Do you still have asthma?" determined current doctor-diagnosed asthma. Other items included the SF-12, the Kessler-10 index of psychological distress, questions on feelings of lack of control in different areas of life, and on mental health conditions.

RESULTS

From the available sample of 10 080, 7619 interviews were completed (participation rate 74.8%), with 834 people reporting current doctor-diagnosed asthma (11.2%). Psychological distress was more frequent in those with asthma (17.9% v 12.2%, p<0.01) and a higher proportion with asthma were at higher risk for anxiety or depression (40.5% v 31.2%, p<0.01). Mental health conditions were also more common (16.2% v 10.8%, p<0.01), as was the frequency of those who sometimes or always felt a lack of control over their health (33.5% v 24.3%, p<0.01). People with both asthma and psychological distress had significantly lower scores on the SF-12 physical component summary (PCS) than those with either asthma or distress alone. Among those with psychological distress, mental component summary (MCS) scores did not differ between asthmatic and non-asthmatic respondents. In a multiple regression model the frequency of a feeling of lack of control over health-together with age, family's financial situation, education level, and number of days partially unable to work or perform usual duties-was significantly associated with scores on the PCS (r = 0.73, adjusted r2 = 0.54).

CONCLUSION

These results, from a representative population sample, show that psychological distress and decreased feelings of control are common in asthma and are significantly associated with physical health status.

Modulation of regulatory T cell immunity by the neuropeptide alpha-melanocyte stimulating hormone

Although many immunosuppressive factors have been identified in the eye, one of these factors, alpha-melanocyte stimulating hormone (alpha-MSH), both suppresses the activation of inflammatory activity by primed T cells and induces the activation of regulatory T cells (Treg cells). This neuropeptide alone at its ocular physiological concentration can account for most of the immunosuppressive activity of aqueous humor (the fluid filing the anterior chamber of the eye). Aqueous humor made devoid of alpha-MSH no longer suppresses IFN-gamma production by Th1 cells. It is alpha-MSH that mediates aqueous humor induction of regulatory T cells. What we have found is that alpha-MSH mediates the induction of C4+ CD25+ Treg cells, and that if the alpha-MSH Treg cells are specific to an autoantigen they can be used to suppress autoimmune disease. It is the objective of this review to demonstrate how we came to discover that alpha-MSH could have such an important role in the extreme regional immunity of the immune privileged eye and how this discovery could be applied to create or reestablish tolerance to prevent autoimmune disease.

Effect of diazepam treatment on metabolic indices in trained and untrained rats

Exercise training, like diazepam, is commonly employed as a means of reducing anxiety. Both diazepam and exercise training have been shown to modify carbohydrate and lipid metabolism as well as influence calcium metabolism in skeletal muscle. As receptor binding and thereby efficacy of diazepam has been demonstrated to be modulated by the lipid environment of the receptor, and changes in calcium levels can affect a number of intracellular signalling pathways, we sought to determine if the interaction of both chronic diazepam and exercise training would modify selected metabolic indices in an animal model. For this purpose, muscle and liver glycogen, blood glucose and plasma free fatty acids (FFA) were measured in sedentary, exercise trained and exercise trained, acutely exhausted animals. Alterations in lipid and carbohydrate metabolism were observed in all experimental groups. Diazepam treatment alone exerts metabolic consequences, such as elevated muscle glycogen and plasma FFA and depressed blood glucose levels, which are similar to those observed with exercise training. When animals are acutely exercised to exhaustion, however, differences appear, including a reduced rise in plasma FFA, which suggests that long-term diazepam treatment does influence exercise metabolism, possibly as a result of effects on the sympatho-adrenal system.

Hormone replacement therapy use over a decade in an Australian population

OBJECTIVES

To describe the prevalence of hormone replacement therapy (HRT) during the 1990s in an Australian population and the length of time this therapy has been used. Design Data were obtained from five biennial representative population face-to-face interview surveys of the South Australian population from 1991 to 2000, and an additional telephone survey in 2001. The main surveys used consistent methods and quality control procedures.

PARTICIPANTS

Over 3000 South Australian adults were interviewed in their own homes by trained health interviewers in each of the biennial surveys.

RESULTS

In 2000, 28% of women aged over 50 were currently using HRT, and ever-use of HRT was 43%. Highest use of HRT was in the 55-59-year age group, where current use was 47% and ever-use was 70%. Among women 55 years and older there was a statistically significant increase in the prevalence of HRT use between 1991 and 2000. Mean length of use in women aged over 55 years increased from 5.4 years in 1991 to 9.6 years in 2000.

CONCLUSIONS

Consistent surveillance of the population has shown that HRT use has not increased before age 55, but has greatly increased thereafter. Long-term effects may now be occurring, and further results of current long-term randomized trials are awaited to confirm the overall risk/benefit ratio suggested by observational studies and early results from long-term trials.

Adaptation to exercise-induced oxidative stress: from muscle to brain

Exercise increases the generation of reactive oxygen and nitrogen species (RONS) and by causing adaptation, could decrease the incidence of RONS-associated diseases. A single bout of exercise, depending upon intensity and duration, can cause an increase in antioxidant enzyme activity, decrease levels of thiols and antioxidant vitamins, and result in oxidative damage as a sign of incomplete adaptation. Increased levels of RONS and oxidative damage are initiators of a specific adaptive response, such as the stimulation of the activation of antioxidant enzymes, thiols, and enhanced oxidative damage repair. Regular exercise has the capability to develop compensation to oxidative stress, resulting in overcompensation against the increased level of RONS production and oxidative damage. Regular exercise causes adaptation of the antioxidant and repair systems, which could result in a decreased base level of oxidative damage and increased resistance to oxidative stress.

Telomerase activity is not altered by regular strenuous exercise in skeletal muscle or by sarcoma in liver of rats

Telomerase is a specialized ribonucleoprotein enzyme complex which prevents the loss of the telomere. The activity of telomerase can be up- and down-regulated by various oxidative stresses but the effect of physical exercise is not known, whereas the modifying effect of cancer on telomerase activity is well documented. In the first study, we investigated the effect of mild and strenuous exercise training on telomerase activity, assessed by a PCR ELISA kit. No alteration in telomerase activity was detected. In the second investigation, solid sarcoma cells were transplanted to control, exercise trained or exercise trained and still exercising mice. On the 16th day after the transplantation, the size of tumors in the exercise trained group was 72% and in the exercising group 57% (P < 0.05) of that in the controls. Telomerase activity and 8-hydroxy-2'-deoxyguanosine levels in the liver were not significantly altered by exercise and/or sarcoma. We conclude that mild and strenuous exercise training does not significantly affect the activity of telomerase in the systems studied. Exercise training during sarcoma significantly retards the development of tumors and could possibly serve as a positive adjunct to treatment.

Immune response to intragraft antigen in draining lymph nodes after corneal transplantation is mediated by interleukin-12

To examine the molecular basis of immunity generated to intragraft antigens and determine whether it differs between acceptor and rejector hosts, we used a novel in vitro system to assay the T cell response to a specific antigen, ovalbumin (OVA), in the graft. OVA-containing corneas were orthotopically grafted into syngeneic or allogeneic hosts. Draining cervical lymph nodes (cLN) were assayed for OVA-specific T cell proliferation and cytokine production. In addition, cytokine production was assayed in cultures of antigen-presented cells (APC) isolated from cLN cultured with OVA-specific DO11.10 T cells and OVA. OVA-specific immunity was detected only in the draining cLN of mice following allogeneic, but not syngeneic, grafting, and this immunity was evident well before any demonstrable alloresponse in the graft. In addition, cLN cells from mice that accepted their corneal allografts produced significantly less interferon-gamma (IFN-gamma) when stimulated in culture than cells harvested from cLN of rejector hosts. Moreover, APC isolated from cLN of acceptor hosts produced significantly lower levels of IL-12. These data suggest that the induction of immunity to corneal antigens in the draining cLN occurs via an interleukin-12 (IL-12) and IFN-gamma-dependent mechanism. Targeting this process may serve as an effective immunomodulatory strategy in corneal transplantation.

Determinants of oxygen uptake kinetics in older humans following single-limb endurance exercise training

We hypothesised that the observed acceleration in the kinetics of exercise on-transient oxygen uptake (VO2) of five older humans (77 +/- 7 years (mean +/- S.D.) following 9 weeks of single-leg endurance exercise training was due to adaptations at the level of the muscle cell. Prior to, and following training, subjects performed constant-load single-limb knee extension exercise. Following training VO2 kinetics (phase 2, tau) were accelerated in the trained leg (week 0, 92 +/- 44 s; week 9, 48 +/- 22 s) and unchanged in the untrained leg (week 0, 104 +/- 43 s; week 9, 126 +/- 35 s). The kinetics of mean blood velocity in the femoral artery were faster than the kinetics of VO2, but were unchanged in both the trained (week 0, 19 +/- 10 s; week 9, 26 +/- 11 s) and untrained leg (week 0, 20 +/- 18 s; week 9, 18 +/- 10 s). Maximal citrate synthase activity, measured from biopsies of the vastus lateralis muscle, increased (P < 0.05) in the trained leg (week 0, 6.7 +/- 2.0 micromol x (g wet wt)(-1) x min(-1); week 9, 11.4 +/- 3.6 micromol x (g wet wt)(-1) x min(-1)) but was unchanged in the untrained leg (week 0, 5.9 +/- 0.5 micromol x (g wet wt)(-1) x min(-1); week 9, 7.9 +/- 1.9 micromol x (g wet wt)(-1) x min(-1)). These data suggest that the acceleration of VO2 kinetics was due to an improved rate of O2 utilisation by the muscle, but was not a result of increased O2 delivery.

Neural control of ocular immune privilege

Ocular immune privilege arises from interactions between the immune apparatus and the eye itself, thereby providing immune protection for the eye that is devoid of sight-threatening inflammation. On the one hand, antigens injected intraocularly elicit deviant systemic immune responses that are devoid of immunogenic inflammation (Anterior Chamber-Associated Immune Deviation, ACAID). On the other hand, the ocular microenvironment (aqueous humor, secreted by cells that surround this chamber) suppresses intraocular expression of immunogenic inflammation. Several lines of evidence indicate that ocular immune privilege is under neural control. First, aqueous humor contains neuropeptides (alpha-MSH, VIP, CGRP) that inhibit and alter the functional properties of T lymphocytes and macrophages. Second, when corneal nerves are severed, the tissues surrounding the anterior chamber cease secreting immunosuppressive factors and ACAID fails--until the nerves regrow. Third, light deprivation abolishes the capacity of the anterior chamber to support ACAID induction, a process that is sensitive to neuropeptides and melatonin. The photoreceptor(s) responsible for ACAID are connected to the nervous system and may reside in the anterior segment and/or the retina. Thus, neural elements from the central nervous system and within the eye help to shape both the induction and the expression of ocular immunity, thereby promoting immune privilege.

Neuropeptide regulation of immunity. The immunosuppressive activity of alpha-melanocyte-stimulating hormone (alpha-MSH)

The ocular microenvironment is an extreme example of regional immunity. Within its microenvironment, expression of delayed type hypersensitivity (DTH) is suppressed. This immunosuppression is mediated in part by the constitutive expression of alpha-MSH. Previously we have found that alpha-MSH suppresses the production of IFN-gamma by activated effector T cells. Recently we have found that alpha-MSH can mediate induction of TGF-beta-producing T cells that act as regulatory T cells. This has encouraged us to further examine the potential for alpha-MSH to suppress T cell-mediated inflammation (autoimmune disease) and to regulate lymphokine production by effector T cells. When alpha-MSH was injected i.v. into mice at the time of peak retinal inflammation, the severity of experimental autoimmune uveitis (EAU) was significantly suppressed. Effector T cells activated in vitro in the presence of alpha-MSH proliferated and produced IL-4 and enhanced levels of TGF-beta while their IFN-gamma and IL-10 production was suppressed. The alpha-MSH-treated T cells functioned as regulatory T cells by suppressing in vitro IFN-gamma production by other inflammatory T cells. This regulatory activity was the function of alpha-MSH-treated CD4+ CD25+ T cells. Therefore, alpha-MSH mediates immunosuppression by inducing a differential expression of lymphokine production and by inducing activation of regulatory functions in T cells. This implies that alpha-MSH may take part in regional mechanisms of immunosuppression and possibly peripheral tolerance. Thus, alpha-MSH can be used to suppress autoimmune disease and possibly reestablish tolerance to autoantigens.

Comparison of fructose and glucose ingestion before and during endurance cycling to exhaustion

BACKGROUND

Pre-exercise and exercise ingestion of fructose and glucose during cycling exercise were compared.

METHODS

EXPERIMENTAL DESIGN

Seventeen trained subjects ingested a placebo prior to and during a cycling test to exhaustion at 75% VO2max (control group = CG). One week later, subjects were matched on exercise time to exhaustion (ETE) and assigned to a fructose group (FG) or a glucose group (GG). Subjects then performed a second cycling test to exhaustion, ingesting fructose or glucose doses. For all groups (CG, FG and GG), blood was drawn before and at timed intervals during exercise to determine glucose, lactate and free fatty acid (FFA) levels.

RESULTS

The ETE for CG was less than either FG (p<0.02) or GG (p<0.001) but FG and GG were similar. FG and GG did not show any differences in blood lactate or blood FFA during the ETE. However, CG FFA levels were higher than those of FG (p<0.02) prior to exercise.

CONCLUSIONS

This study demonstrated that fructose and glucose are of equal value in prolonging ETE in endurance cycling Ingesting fructose before and during exercise apparently provided a more constant supply of glucose to be available to the working muscles. The more stable blood glucose levels with fructose ingestion may be beneficial in reducing perceived exhaustion, and thereby allowing for an enhancement in exercise performance.

The prevalence of pelvic floor disorders and their relationship to gender, age, parity and mode of delivery

OBJECTIVE

To define the prevalence of pelvic floor disorders in a non-institutionalised community and to determine the relationship to gender, age, parity and mode of delivery.

DESIGN

A representative population survey using the 1998 South Australian Health Omnibus Survey.

SAMPLE

Random selection of 4400 households; 3010 interviews were conducted in the respondents' homes by trained female interviewers. This cross sectional survey included men and women aged 15-97 years.

RESULTS

The prevalence of all types of self-reported urinary incontinence in men was 4.4% and in women was 35.3% (P<0.001). Urinary incontinence was more commonly reported in nulliparous women than men and increased after pregnancy according to parity and age. The highest prevalence (51.9%) was reported in women aged 70-74 years. The prevalence of flatus and faecal incontinence was 6.8% and 2.3% in men and 10.9% and 3.5% in women, respectively. Pregnancy (> 20 weeks), regardless of the mode of delivery, greatly increased the prevalence of major pelvic floor dysfunction, defined as any type of incontinence, symptoms of prolapse or previous pelvic floor surgery. Multivariate logistic regression showed that, compared with nulliparity, pelvic floor dysfunction was significantly associated with caesarean section (OR 2.5, 95% CI 1.5-4.3), spontaneous vaginal delivery (OR 3.4, 95% CI 2.4-4.9) and at least one instrumental delivery (OR 4.3, 95% CI 2.8-6.6). The difference between caesarean and instrumental delivery was significant (P<0.03) but was not for caesarean and spontaneous delivery. Other associations with pelvic floor morbidity were age, body mass index, coughing, osteoporosis, arthritis and reduced quality of life scores. Symptoms of haemorrhoids also increased with age and parity and were reported in 19.9% of men and 30.2% of women.

CONCLUSION

Pelvic floor disorders are very common and are strongly associated with female gender, ageing, pregnancy, parity and instrumental delivery. Caesarean delivery is not associated with a significant reduction in long term pelvic floor morbidity compared with spontaneous vaginal delivery.

A decade of aerobic endurance training: histological evidence for fibre type transformation

BACKGROUND

Researchers employing a variety of training methods have demonstrated a fast-to-slow fibre transformation in animal skeletal muscle. The observation as to whether this occurs in exercise trained humans is limited and equivocal.

METHODS

EXPERIMENTAL DESIGN

to examine this issue, skeletal muscle from seven subjects who had participated in a decade or more of high intensity aerobic training (DT) and six nontrained (NT) subjects was obtained by muscle biopsy from the vastus lateralis muscle (VL) and subjected to a modified myofibrillar ATPase technique to identify muscle fibre types. Muscle tissue was histochemically treated by exposure to an alkaline preincubation (pH 9.9), an acid preincubation (pH 4.3 or 4.6) and the formate-KCI preincubation buffer (pH 4.54), previously employed in animal studies.

RESULTS

The formate-KCl preincubation medium identified all major fibre types at a single pH in human subjects. The percentage of type I fibres in DT was 70.9% vs 37.7% in NT (p<0.01), while the type IIa fibres in DT (25.3%) was much lower (p<0.01) than NT (51.8%). Surprisingly, type IIa fibres in the DT group displayed lesser oxidative staining intensity (p<0.01) than type IIa fibres from the NT group. Mean cross-sectional area of type I fibres for DT (6233.9+/-1421.7 microm2) was greater (p<0.05) than either type I (5746.8+/-1135.2 microm2) or II (5693.5+/-1214.6 microm2) from NT.

CONCLUSIONS

The results revealed that endurance training may promote a transition from type II to type I muscle fibre types and occurs at the expense of the type II fibre population.

Regular training modulates the accumulation of reactive carbonyl derivatives in mitochondrial and cytosolic fractions of rat skeletal muscle

The oxygen flux into the mitochondria of skeletal muscle increases with exercise. However, the extent of oxidative damage to mitochondrial proteins of skeletal muscle has only been estimated. We studied the alteration of reactive carbonyl derivatives (RCD) in mitochondrial and cytosolic fractions of skeletal muscle following 9 weeks of swimming training in rats. The RCD content of mitochondria was significantly elevated compared with the cytosolic fraction of both control and exercised animals. Accumulation of RCD in muscle mitochondria of the exercised group was also significantly elevated (P < 0.05). On the other hand, alteration of the accumulation of RCD was not apparent in the cytosolic fraction of skeletal muscle. The activity of proteasome complex, however, was increased in the cytosolic fraction of exercised muscle (P < 0.05). The data suggest that mitochondria of skeletal muscle accumulate significantly larger amounts of RCD than the cytosolic fraction and the tendency of the accumulation varies in cell fractions. Exercise training increases the accumulation of protein damage in mitochondria of skeletal muscle but cytosolic proteins are protected by increased activity of proteasome complex and possibly by other antioxidant enzymes.

IL-6 antagonizes TGF-beta and abolishes immune privilege in eyes with endotoxin-induced uveitis

PURPOSE

To determine the immunosuppressive status of aqueous humor (AqH) from mouse eyes afflicted with endotoxin-induced uveitis (EIU) and to identify the relevant cytokines responsible for immunomodulatory activity within EIU AqH.

METHODS

Bacterial lipopolysaccharide (LPS) was injected into hind footpads of C3H/HeN mice; and AqH, collected at 6, 12, 24, and 48 hours, was evaluated for content of transforming growth factor (TGF)-beta, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, and interferon (IFN)-gamma and capacity to suppress anti-CD3-driven T-cell proliferation. Cytokine mRNA expression in iris-ciliary body (I/CB) was analyzed by RNase protection assays.

RESULTS

During 6 to 24 hours after LPS injection, total TGF-beta levels in AqH increased even though the fluid lost its capacity to suppress T-cell activation. At this time, AqH contained high levels of IL-6, and I/CB contained high levels of IL-6 mRNA. When IL-6 was neutralized with specific antibodies, inflamed AqH reacquired its capacity to suppress T-cell activation, which correlated with high levels of TGF-beta. Coinjection of IL-6 plus antigen into the anterior chamber of the eye of normal mice prevented antigen-specific anterior chamber-associated immune deviation (ACAID).

CONCLUSIONS

LPS-induced intraocular inflammation is associated with local production of IL-6, which robs AqH of its immunosuppressive activity, perhaps by antagonizing TGF-beta. The fact that IL-6 antagonized ACAID induction in normal eyes suggests that strategies to suppress the intraocular synthesis of IL-6 may reduce inflammation and restore ocular immune privilege.

Changes in rat muscle with compensatory overload occur in a sequential manner

The present study was initiated to determine the time course of changes in the profile of selected skeletal muscle myofibril proteins during compensatory overload. Whole muscle isometric contractile properties were measured to assess the physiological consequences of the overload stimulus. Compensatory overload of plantaris muscle of rats was induced by surgical ablation of the synergistic soleus and gastrocnemius muscles. Myosin light chain (LC) and tropomyosin (TM) compositions of control (CP) and overloaded plantaris (OP) muscles were determined by electrophoresis and myofibrillar ATPase assays were performed to assess changes in contractile protein interactions. Within one week of overload decreases in the alpha:beta TM ratio and myofibrillar ATPase activity were observed. Following 30 days of overload, a transition in type II to type I fibres was associated with an increase in slow myosin LC1. Interestingly, after 77 days of overload, the TM subunit ratio returned to one resembling a fast twitch muscle. It is proposed that the early and transitory changes in the TM subunits of OP, as well as the rapid initial depression in maximum tetanic isometric force and myofibrillar ATPase activity may be explained as a result of muscle fibre degeneration-regeneration. We propose that alterations in protein expression induced by compensatory overload reflect both degenerative-regenerative change and increased neuromuscular activity.

Prenylflavonoid variation in Humulus lupulus: distribution and taxonomic significance of xanthogalenol and 4'-O-methylxanthohumol

The resins produced by either lupulin or leaf glands of over 120 plants of Humulus lupulus and one plant of H. japonicus (Cannabinaceae) were analyzed for the presence of prenylated flavonoids. The H. lupulus taxa investigated were H. lupulus var. lupulus from Europe, H. lupulus var. cordifolius from Japan, and H. lupulus from North America. Fifty-two of the plants examined were cultivars of European, American, and Japanese origin. Twenty-two flavonoids were detected in the glandular exudates of H. lupulus by HPLC-MS MS. Xanthohumol (3'-prenyl-6'-O-methylchalconaringenin) was the principal prenylflavonoid in all H. lupulus plants and was accompanied by 11 structurally similar chalcones. Ten flavonoids were identified as the flavanone isomers of these chalcones. Three other prenylchalcones were isolated from H. lupulus cv. 'Galena', one of which was identified as 3'-prenyl-4'-O-methylchalconaringenin (named 'xanthogalenol'). The distribution of three 4'-O-methylchalcones, i.e. xanthogalenol, 4'-O-methylxanthohumol, and 4',6'-di-O-methylchalconaringenin, was found to be limited to wild American plants from the Missouri-Mississippi river basin, H. lupulus var. cordifolius, and most of their descendents. These 4'-O-methylchalcones were absent from cultivars of European origin, and from wild hops from Europe and southwestern USA. The flavonoid dichotomy (presence versus absence of 4'-O-methylchalcones) indicates that there are at least two evolutionary lineages within H. lupulus (European and Japanese American), which is in agreement with morphological, molecular, and phytogeographical evidence. Leaf glands of H. japonicus from eastern Asia did not produce the H. lupulus prenylflavonoids.

Changes in urine 8-hydroxydeoxyguanosine levels of super-marathon runners during a four-day race period

We have determined the urinary 8-hydroxydeoxyguanosine (8-OHdG) levels of five well trained supra-marathon runners during a four-day race. The daily running distances of the four-day race were the following; 93 km, 120 km, 56 km and 59 km, respectively. Pre-race and post-race urine samples were collected on each day and analyzed by a monoclonal antibody technique. The urinary 8-OHdG content increased significantly on the first day and tended to decrease from the third day. By the fourth day 8-OHdG content was significantly less than measured on the first three days. The serum creatine kinase activity changed in a similar fashion, showing a large increase (P<0.001) up to the third day when it decreased significantly from the peak value (P<0.05). We conclude that extreme physical exercise causes oxidative DNA damage to well trained athletes. However, repeated extreme exercise-induced oxidative stress does not propagate on increase of urinary 8-OHdG, but rather causes an adaptation leading to normalization of oxidative DNA damage.

Mental health status of the South Australian population

OBJECTIVE

To determine, by the use of a telephone survey, the mental health status of SA adults (18+ years) using the GHQ-28, SF-12 and self-report as indicators of mental health, and to examine risk factors for mental health morbidity.

SAMPLE

A random representative sample of South Australian adults selected from the Electronic White Pages. Overall, 2,501 interviews were conducted (74.0% response rate).

RESULTS

Overall, 19.5% of respondents had a mental health problem as determined by the GHQ-28, 11.8% as determined by the mental health component summary score of the SF-12 and 11.9% self-reported a mental health condition. The percentage of people with a mental health problem who had used a psychologist or a psychiatrist in the previous 12 months was 9.6% for people diagnosed by the GHQ-28, 16.2% by SF-12 and 23.7% for self-report. The logistic regression analyses undertaken to describe people with a mental health problem as determined by the GHQ-28 and to describe people who visited a psychologist or psychiatrist produced different age categories, demographic and co-morbidity indicators. Variables found in both analyses included living in the metropolitan area, being economically inactive and being a high user of health services.

CONCLUSIONS

One in five South Australian adults has a mental problem. Although the prevalence is higher for younger age groups, older adults are more likely to visit a psychologist or a psychiatrist.

IMPLICATIONS

Telephone interviewing produces robust indicators of the prevalence of mental health problems and is a cost-effective way of identifying prevalence estimates or tracking changes over time.

Muscle metabolism during heavy-intensity exercise after acute acetazolamide administration

Carbonic anhydrase (CA) inhibition is associated with a lower plasma lactate concentration ([La(-)](pl)), but the mechanism for this association is not known. The effect of CA inhibition on muscle high-energy phosphates [ATP and phosphocreatine (PCr)], lactate ([La(-)](m)), and glycogen was examined in seven men [28 +/- 3 (SE) yr] during cycling exercise under control (Con) and acute CA inhibition with acetazolamide (Acz; 10 mg/kg body wt iv). Subjects performed 6-min step transitions in work rate from 0 W to a work rate corresponding to approximately 50% of the difference between the O(2) uptake at the ventilatory threshold and peak O(2) uptake. Muscle biopsies were taken from the vastus lateralis at rest, at 30 min postinfusion, at end exercise (EE), and at 5 and 30 min postexercise. Arterialized venous blood was sampled from a dorsal hand vein and analyzed for [La(-)](pl). ATP was unchanged from rest values; no difference between Con and Acz was observed. The fall in PCr from rest [72 +/- 3 and 73 +/- 3.6 (SE) mmol/kg dry wt for Con and Acz, respectively] to EE (51 +/- 4 and 46 +/- 5 mmol/kg dry wt for Con and Acz, respectively) was similar in Con and Acz. At EE, glycogen (mmol glucosyl units/kg dry wt) decreased to similar values in Con and Acz (307 +/- 16 and 300 +/- 19, respectively). At EE, no difference was observed in [La(-)](m) between conditions (46 +/- 6 and 43 +/- 5 mmol/kg dry wt for Con and Acz, respectively). EE [La(-)](pl) was higher during Con than during Acz (11.4 +/- 1.0 vs. 8.2 +/- 0.6 mmol/l). The similar [La(-)](m) but lower [La(-)](pl) suggests that the uptake of La(-) by other tissues is enhanced after CA inhibition.

Analysis of immunomodulatory activities of aqueous humor from eyes of mice with experimental autoimmune uveitis

Aqueous humor (AqH) contains immunosuppressive factors, especially TGF-beta2, that contribute to the immune privileged status of the anterior chamber. However, this may not be true when the blood-ocular barrier is compromised by ocular inflammation. To determine the immunosuppressive status of AqH from murine eyes afflicted with experimental autoimmune uveitis, B10.A mice were immunized with interphotoreceptor retinoid-binding protein. AqH was collected from eyes of affected mice periodically after immunization and then evaluated for content of TGF-beta, proinflammatory cytokines, and the capacity to suppress anti-CD3-driven T cell proliferation. mRNA expression of selected cytokines in iris and ciliary body from inflamed eyes was analyzed by ribonuclease protection assay. We found that TGF-beta levels were significantly increased in AqH from EAU eyes on days 11, 17, and 28. AqH collected on day 11 (onset of disease) failed to suppress T cell proliferation and contained large amounts of locally produced IL-6 that antagonized TGF-beta. In contrast, AqH collected at 17 days (when ocular inflammation was progressively severe) re-expressed the ability to suppress T cell proliferation, in this case due to high levels of blood-derived TGF-beta1 and eye-derived TGF-beta2 in the absence of IL-6. Thus, during the onset of experimental autoimmune uveitis, the ocular microenvironment loses its immunosuppressive properties due to local production of IL-6. But as inflammation mounts, AqH IL-6 content falls, and the fluid reacquires sufficient TGF-beta eventually to suppress immunogenic inflammation. The paradoxical roles of IL-6 in antagonizing TGF-beta, while promoting TGF-beta accumulation during ocular inflammation, is discussed.

Random digit dialling and Electronic White Pages samples compared: demographic profiles and health estimates

OBJECTIVE

To compare the methodologies of and health estimates derived from two telephone household survey methods. In particular, to establish if White Pages telephone listings provide a relatively unbiased sampling frame for population health surveys.

METHOD

In South Australia in 1998, a health survey questionnaire was administered by telephone to two randomly selected population samples. The first method used EWP (Electronic White Pages, n = 6,012), which contains all listed residential telephone numbers as the sampling frame. The results were compared to a RDD (random digit dialling, n = 3,080) sample where all listed and unlisted telephone numbers were included in the sampling frame. Demographic variables and health estimates were compared between the surveys, and then compared to a 'gold standard' door-to-door household survey conducted concurrently.

RESULTS

The response rate for EWP (83.8%) exceeded that of RDD (65.4%). More than four times as many calls were required per completed interview in RDD. Demographic profiles and health estimates were substantially similar.

CONCLUSIONS

EWP requires fewer telephone calls and enables approach letters establishing the bona fides of the survey to be sent to each selected address before calling, increasing the response rate. RDD is a more inclusive sampling frame but also includes non-connected and business numbers, and offers no significant advantages in providing health estimates.

IMPLICATIONS

There are substantial methodological and cost advantages in using EWP over RDD as the sampling, frame for population health surveys, without introducing significant bias into health estimates.

Reliability of self-reported behavioural health risk factors in a South Australian telephone survey

OBJECTIVE

To test the reliability of telephone health survey questions.

METHOD

A telephone survey on mental health of South Australians in 1997 was re-administered to a random sub-sample of 102 respondents between 32 and 79 days after the original survey.

RESULTS

Demographic questions (age, gender, number of adults and children in the household) showed the highest reproducibility and were almost perfect. Questions regarding health risk factors, such as smoking and drinking behaviour, showed substantial to almost perfect agreement. Co-morbidity variables were substantially reproducible where prevalence estimates were not close to zero.

CONCLUSIONS

The results were comparable to findings from similar studies associated with the Behavioral Risk Factor Surveillance System (BRFSS) in the United States. The study suggests that the telephone health survey instrument used in South Australia is reliable for estimating health conditions and behaviours in the population.

Specific aqueous humor factors induce activation of regulatory T cells

PURPOSE

To examine the possibility that aqueous humor-induced regulatory T cells could function in vivo, these T cells were examined for their ability to suppress adoptive transfer of delayed-type hypersensitivity (DTH). To begin to understand the mechanisms by which aqueous humor induces activation of regulatory T cells, alpha-melanocyte stimulating hormone (MSH) and transforming growth factor (TGF)-beta2 were examined for ability to induce regulatory T cells.

METHODS

Primed T cells were treated with aqueous humor and assayed for regulatory activity by injecting them intravenously along with DTH-mediating T cells into syngeneic mice. Antigen-pulsed antigen-presenting cells (APCs) were injected into the pinna of the mouse ear, and swelling was measured 24 hours later. Primed T cells were also activated in vitro in the presence of alpha-MSH, TGF-beta1, or TGF-beta2 and were assayed for proliferation and TGF-beta production along with suppressing DTH.

RESULTS

Aqueous humor-treated T cells suppressed inflammation mediated by DTH T cells. Maximum regulatory T cell activity was induced when primed T cells were activated in vitro in the presence of alpha-MSH followed 4 hours later with active TGF-beta2. Such T cells proliferated, produced TGF-beta, and suppressed DTH, suggesting that alpha-MSH and TGF-beta2 induce activation of regulatory T cells. No regulatory T cell activity could be induced in the presence of TGF-beta1.

CONCLUSIONS

The ocular microenvironment constitutively produces immunoregulatory factors that suppress the induction of inflammatory activity and promotes regulatory T cell activity. Such regulatory T cells can further contribute to maintaining the normal immunosuppressive ocular microenvironment through their ability to suppress activation of other inflammatory T cells.

Effects of experimental ocular inflammation on ocular immune privilege

PURPOSE

To determine whether the inflammation of endotoxin-induced uveitis (EIU) and experimental autoimmune uveoretinitis (EAU) alters key in vivo and in vitro parameters of ocular immune privilege.

METHODS

For EIU induction, C3H/HeN mice received 200 microg lipopolysaccharide (LPS). For EAU induction, B10.A mice were immunized with 50 microg interphotoreceptor retinoid-binding protein (IRBP) mixed with complete Freund's adjuvant. Aqueous humor (AqH) was collected at periodic intervals and assayed for leukocyte content and the ability to suppress or enhance T-cell proliferation. Eyes with EAU were assessed for the capacity to support anterior chamber (AC)-associated immune deviation (ACAID) induction after injection of ovalbumin (OVA).

RESULTS

Inflammation within the anterior segment in EIU peaked at 12 to 24 hours and was detected from 10 days onward in EAU. In AqH of EIU, protein content rose within 4 hours, followed by infiltrating leukocytes. EIU AqH promptly lost its capacity to suppress T-cell proliferation and became mitogenic for T cells. In AqH of EAU, protein and leukocyte content rose at 11 days and continued to remain elevated thereafter. Whereas 11-day EAU AqH failed to suppress T-cell proliferation, AqH at later time points reacquired immunosuppressive properties. Injection of OVA into the AC of eyes of mice with EAU failed to induce ACAID.

CONCLUSIONS

The intraocular inflammation of EIU and EAU disrupted important parameters of immune privilege, ranging from breakdown of the blood- ocular barrier, to loss of an immunosuppressive microenvironment, to abrogation of ACAID. Because AqH from inflamed EAU reacquired the ability to suppress T-cell proliferation, the authors conclude that the capacity to regulate immune expression and inflammation can be a property even of inflamed eyes.

Hormone replacement therapies in women at risk of cardiovascular disease and osteoporosis in South Australia in 1997

OBJECTIVE

To describe changes in use of hormone replacement therapy (HRT) in an Australian population and to determine HRT use in women at risk of cardiovascular disease and osteoporotic fracture.

DESIGN

Data were derived from the 1997 South Australian Health Omnibus Survey (a representative population survey) and compared with data from 1991, 1993 and 1995 Omnibus Surveys.

SETTING

South Australia, 1997.

PARTICIPANTS

1049 women aged 40 years and over from a random selection of 4400 households.

RESULTS

Among women aged 55-64 years (and thus likely to be postmenopausal), 60% had used HRT (ever use). Nearly two-thirds of these women used it currently. In this age group, mean length of HRT use had increased to 70 months (median, 60 months). Rates of HRT use had not changed significantly between 1991 and 1997 in women under 55 years, but had increased significantly in women aged 55 years or over (P < or = 0.01). Among women currently using HRT, 5.4% had used testosterone therapy, while 4% used unregistered products purported to contain hormones. Rates of ever use of HRT in women with zero, one, two, or three or more cardiovascular risk factors were 33%, 37%, and 45%, respectively. Among women with a diagnosis of osteoporosis, 52% had used HRT, with a mean length of use of 86 months (median, 60 months).

CONCLUSION

HRT use is increasing in older-age groups. Longer-term therapy with potential for primary prevention is now occurring, but half of those with osteoporosis and more than half of those with risk factors for cardiovascular disease have not used HRT.

Fate of xanthohumol and related prenylflavonoids from hops to beer

The fate of three prenylated flavonoids of the chalcone type, xanthohumol, desmethylxanthohumol, and 3'-geranylchalconaringenin, was monitored with LC/MS-MS from hops (Humulus lupulus L.) to beer in two brewing trials. The three prenylchalcones were largely converted into their isomeric flavanones, isoxanthohumol, prenylnaringenins, and geranylnaringenins, respectively, in the boiling wort. Losses of prenylflavonoids were due to incomplete extraction from the hops into the wort (13-25%), adsorption to insoluble malt proteins (18-26%), and adsorption to yeast cells (11-32%) during fermentation. The overall yield of xanthohumol, after lagering of the beer and largely in the form of isoxanthohumol, amounted to 22-30% of the hops' xanthohumol. About 10% of the hops' desmethylxanthohumol, completely converted into prenylnaringenins, remained in the beers. 3'-Geranylchalconaringenin behaved similarly to desmethylxanthohumol. Solubility experiments indicated that (1) malt carbohydrates form soluble complexes with xanthohumol and isoxanthohumol and (2) solubility does not dictate the isoxanthohumol levels of finished beers.

Mice with Th2-biased immune systems accept orthotopic corneal allografts placed in "high risk" eyes

CD4+ T cells of the Th1 type play a central role in acute rejection of solid tissue grafts, including orthotopic corneal allografts. Th1 cells, which mediate delayed hypersensitivity, are the polar opposites of CD4+ Th2 cells, and the latter cells cross-regulate Th1 cells through the unique pattern of cytokines they secrete. As such, Th2 cells may have a useful role to play in preventing rejection of corneal allografts. To test this possibility, the immune systems of adult mice were biased toward Th2 responses by immunization with keyhole limpet hemocyanin plus IFA. When immunized subsequently with either OVA or allogeneic corneal tissue, these mice acquired Ag-specific primed T cells of the Th2 type. More important, allogeneic corneas grafted into neovascularized eyes of Th2-biased mice experienced significantly enhanced survival. To demonstrate that enhanced survival was promoted by donor-specific Th2 cells, lymphoid cells from keyhole limpet hemocyanin-immune mice bearing healthy corneal allografts suppressed orthotopic corneal allograft rejection when adoptively transferred into naive, syngeneic recipients. We conclude that acceptance of corneal allografts in neovascularized mouse eyes can be significantly enhanced by biasing the recipient immune system toward Th2 responses.

The epidemiology of hearing impairment in an Australian adult population

BACKGROUND

This study measured the prevalence of hearing impairment, and major demographic factors that influence the prevalence, in a representative South Australian adult population sample aged > or = 15 years.

METHODS

The study group was recruited from representative population surveys of South Australians. Participants in these surveys who reported a hearing disability were then recruited to an audiological study which measured air and bone conduction thresholds. In addition a sample of those people who reported no hearing disability were recruited to the audiological study.

RESULTS

The data reported in this study are the first in Australia to assess the prevalence of hearing impairment from a representative population survey using audiological methods. The data show that 16.6% of the South Australian population have a hearing impairment in the better ear at > or = 25 dBHTL and 22.2% in the worse ear at the same level. The results obtained in this representative sample compare well with those obtained in the British Study of Hearing, although some differences were observed.

CONCLUSIONS

Overall, there are only a few studies worldwide that have audiologically assessed the impairment of hearing from a representative population sample. The overall prevalence of hearing impairment in Australia is similar to that found in Great Britain, although there are some differences between the estimates of severity of impairment and some sex differences. The corroboration of the two studies reinforces the status of hearing impairment as the most common disability of adulthood. The present study also showed that there are a large number of Australians who may benefit from a more systematic community-based rehabilitation programme including the fitting of hearing aids. Secondly, the study identified the need for health goals and targets for hearing to be based on an epidemiological approach to the problem.