Levels of physical activity and sitting time in women with infants, toddlers and preschoolers: a population-based cross-sectional study

OBJECTIVES

Insufficient physical activity (PA) and prolonged sitting time (ST) increase the risk of chronic disease and mortality. Caring for young children can potentially impact maternal PA and sedentary behaviours. The aims of this study were to explore the levels of PA and ST in women with young children (infants, toddlers and preschoolers) and sociodemographic and behavioural factors associated with these.

STUDY DESIGN

This was a population-based cross-sectional study.

METHODS

Survey 5 data collected in 2009 (n = 4290) of the 1973-1978 birth cohort of the Australian Longitudinal Study on Women's Health were used. Multiple linear and logistic regression models were used to examine associations.

RESULTS

In adjusted models, compared with women with preschoolers, women whose youngest child was an infant aged 0-6 months, aged >6-12 months or toddler had lower PA (-321.3 MET.min/week [95% confidence interval (CI) -416.2, -226.4], -147.9 MET.min/week [95% CI -237.6, -58.1] and -106.4 MET.min/week [95% CI -172.3, -40.5]). ST was higher in women whose youngest child was an infant aged 0-6 months (0.48 h/day; 95% CI 0.19, 0.77) but lower with infants aged >6-12 months (-0.33 h/day; 95% CI -0.60, -0.05) and toddlers (-0.40 h/day; 95% CI -0.60, -0.20) than in those with preschoolers. The findings were similar in the logistic model. Sociodemographic and behavioural factors such as occupation and marital status also influenced PA and ST.

CONCLUSIONS

Women with infants and toddlers have lower PA than women with preschoolers. Women are more likely to sit more in the first 6 months after childbirth. These findings can inform resources and intervention development to improve activity levels in women with young children through consideration of the age of the youngest child, sociodemographic and behavioural factors.

Immobilization of Proteins with Controlled Load and Orientation

Biomaterials based on immobilized proteins are key elements of many biomedical and industrial technologies. However, applications are limited by an inability to precisely construct materials of high homogeneity and defined content. We present here a general "protein-limited immobilization" strategy by combining the rapid, bioorthogonal, and biocompatible properties of a tetrazine-strained trans-cyclooctene reaction with genetic code expansion to site-specifically place the tetrazine into a protein. For the first time, we use this strategy to immobilize defined amounts of oriented proteins onto beads and flat surfaces in under 5 min at submicromolar concentrations without compromising activity. This approach opens the door to generating and studying diverse protein-based biomaterials that are much more precisely defined and characterized, providing a greater ability to engineer properties across a wide range of applications.

Sitting time and depression in young women over 12-years: The effect of physical activity

OBJECTIVES

Lack of physical activity (PA) and prolonged sitting time (ST) are associated with increased risk of mortality and chronic illnesses, including depression. While there have been claims that the two risks are 'independent', their joint and stratified effects are unclear. The aim of this study was to explore the combined effects of physical activity and sitting time on the 12year risk of depressive symptoms (DS) in young women.

DESIGN

Cohort-9061 young participants in the Australian Longitudinal Study on Women's Health completed triennial surveys from 2000 (age 22-27), to 2012.

METHODS

Generalised Estimating Equation models were used to calculate the joint effects of PA and ST on DS, with <4h/day of ST and the highest PA quartile as the reference categories. Relationships between PA and DS, and between ST and DS, were also examined after stratification by ST and PA respectively.

RESULTS

In the adjusted joint effects model, compared with the reference category (low sitting, high PA), odds for DS were significantly higher in women who sat for >4, 6 and 8h/day and reported doing no PA. In every physical activity category, women who sat for ≥10h/day were at highest risk of DS (OR for lowest physical activity quartile, 1.72 [95% CI=1.38-2.14]; OR for highest physical activity quartile, 1.49 [95% CI=1.16-1.91]). After stratification by ST, odds of DS were reduced in women who reported any physical activity (compared with none), except when ST was >10h/day. After stratification by physical activity, the increased risk of sitting 8-10h/day was attenuated by any physical activity, but there was no reduction in risk of depressive symptoms with increasing PA levels in women who sat for ≥10h per day.

CONCLUSIONS

These data suggest that there are both joint and stratified effects of too little activity and too much sitting on the risk of depressive symptoms in young women. High levels of PA are protective against the hazards of high ST at this life stage, except in women with very high levels of sitting.

Overweight and obesity as major, modifiable risk factors for urinary incontinence in young to mid-aged women: a systematic review and meta-analysis

The purpose of this review and meta-analysis was to evaluate overweight and obesity as risk factors for urinary incontinence in young to mid-aged women. Understanding these relationships during this life stage is important as early onset increases the risk for developing severe and persistent incontinence. A systematic search resulted in 497 citations, 14 of which were retained for review. Data were analysed by overweight and obesity and by subtype of urinary incontinence - stress, urge, mixed and severe. When compared with 'normal' body mass index, overweight was associated with a one-third increase in risk of urinary incontinence (relative risk = 1.35, 95% confidence interval = 1.20-1.53), while the risk was doubled in women with obesity (relative risk = 1.95, 95% confidence interval = 1.58-2.42). When estimates were pooled according to urinary incontinence subtype, there was no statistical difference in risk. Overweight and obesity are strong predictors of urinary incontinence, with a significantly greater risk observed for obesity. Clinical advice to young women at risk of, or presenting with, obesity should not be limited to metabolic health only but should emphasize the role of excess weight on pelvic floor weakening and subsequent risk of incontinence.

Weight management practices associated with PCOS and their relationships with diet and physical activity

STUDY QUESTION

Do weight management practices differ in women with and without PCOS?

SUMMARY ANSWER

Women in the general population with self-reported PCOS are more likely to be using healthy weight management practices and alternative non-lifestyle measures for weight management than women without PCOS.

WHAT IS KNOWN ALREADY

Lifestyle management is the first-line treatment in PCOS. However, the specific weight management practices used by women with PCOS and their effect on diet and physical activity are unclear.

STUDY DESIGN, SIZE, DURATION

The study was a population-based observational cross-sectional study involving women in the 1973-1978 cohort (n = 7767 total; n = 556 with PCOS, n = 7211 without PCOS).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women with and without self-reported PCOS were included. Self-reported outcome measures included healthy lifestyle-related or alternative non-lifestyle-related (e.g. laxatives or smoking) weight management practices, dietary intake and physical activity.

MAIN RESULTS AND THE ROLE OF CHANCE

Women with PCOS were more likely to be following both healthy [reducing meal or snack size (odds ratio (OR) 1.50, 95% CI 1.14, 1.96, P = 0.004) and reducing fat or sugar intake (OR 1.32, 95% CI 1.03, 1.69, P = 0.027) or following a low glycaemic index diet (OR 2.88, 95% CI 2.30, 3.59, P < 0.001)] and alternative [smoking (OR 1.60, 95% CI 1.02, 2.52, P = 0.043) or use of laxative, diet pills, fasting or diuretics (OR 1.45, 95% CI 1.07, 1.97, P = 0.017)] weight management practices than women without PCOS. In PCOS, the use of a range of healthy weight management practices was associated with increases in physical activity (P < 0.001), diet quality (P < 0.001), percentage protein intake (P < 0.001) and decreases in glycaemic index (P < 0.001), and percentages of fat (P = 0.001), saturated fat (P < 0.001) or fibre (P = 0.003). Use of alternative weight management practices was associated with decreases in diet quality.

LIMITATIONS, REASONS FOR CAUTION

Limitations include the use of self-reported data for PCOS, height, weight, diet, physical activity and weight management behaviours.

WIDER IMPLICATIONS OF THE FINDINGS

In PCOS, we should focus on improving healthy weight practices across both diet quality and quantity, and on assessing alternative weight practices and their potential adverse effect on dietary intake.

STUDY FUNDING/COMPETING INTEREST(S)

L.M. is supported by a South Australian Cardiovascular Research Development Program Fellowship (ID AC11S374); a program collaboratively funded by the National Heart Foundation, the South Australian Department of Health and the South Australian Health and Medical Research Institute. H.T. is supported by the NHMRC. S.A.M. is supported by an NHMRC Career Development Fellowship Level 2, ID1104636 and was previously supported by an ARC Future Fellowship (2011-2015, FT100100581). The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

Not applicable.

The influence of long-term exposure and timing of physical activity on new joint pain and stiffness in mid-age women

OBJECTIVE

To examine the influence of long-term exposure and timing of physical activity (PA) on new joint pain/stiffness in mid-age women.

METHODS

Data were from 5105 participants (born 1946-51) in the Australian Longitudinal Study on Women's Health (ALSWH) who completed survey items on PA (1998, 2001 and 2004) and joint pain/stiffness (2007 and 2010). PA was categorized in five levels at each survey and summed into a cumulative PA score (CPA, range 0-12). Associations were analysed using logistic regression, with separate models for the cumulative model (using CPA), the sensitive periods model (i.e., PA measured at each survey in one regression model) and the critical periods model (i.e., separate regression models for PA at each survey).

RESULTS

951 (18.6%) participants reported new-onset joint pain/stiffness. In the cumulative model, CPA was associated joint pain/stiffness when included as a continuous variable (adjusted odds ratio [OR] = 0.97, 95% confidence interval [CI] = 0.95-0.99), but not when included as a categorical variable. In both the sensitive periods and critical periods models, low to high levels of PA in 2001 and 2004 had stronger inverse associations with joint pain/stiffness than PA levels in 1998. The model fit was better for the sensitive periods than the cumulative or critical periods models.

CONCLUSIONS

In mid-age women, PA between the ages 47 and 58 was associated with a lower risk of joint pain/stiffness 9 years later. Associations were stronger for PA in the last 6 years than for earlier PA.

Hot flushes and night sweats are associated with coronary heart disease risk in midlife: a longitudinal study

OBJECTIVE

The purpose of this study was to investigate associations between vasomotor menopausal symptoms (VMS), i.e. hot flushes and night sweats, and the incidence of coronary heart disease (CHD).

DESIGN

A prospective cohort study.

SETTING AND POPULATION

11 725 women, aged 45-50 years at baseline in 1996, were followed up at 3-year intervals for 14 years.

METHODS

Self-reported VMS and incident CHD were measured at each survey.

MAIN OUTCOME MEASURE

We determined the association between VMS and CHD at the subsequent survey, using generalised estimating equation analysis, adjusting for time-varying covariates.

RESULTS

At baseline, 14% reported rarely, 17% reported sometimes, and 7% reported often having night sweats. During follow-up, 187 CHD events occurred. In the age-adjusted analysis, women who reported their frequency of experiencing hot flushes and night sweats as 'often' had a greater than two-fold increased odds of CHD (OR hot flushes 2.18, 95% CI 1.49-3.18; OR night sweats 2.38, 95% CI 1.62-3.50) compared with women with no symptoms (P trend < 0.001 for frequency of symptoms). Adjustment for menopausal status, lifestyle factors, body mass index, diabetes, and hypertension attenuated the associations (OR hot flushes 1.70, 95% CI 1.16-2.51, P trend = 0.01; OR night sweats 1.84, 95% CI 1.24-2.73), P trend = 0.004).

CONCLUSIONS

Women who report having hot flushes or night sweats 'often' have an increased risk of developing CHD over a period of 14 years, even after taking the effects of age, menopause status, lifestyle, and other chronic disease risk factors into account.

Nine year changes in sitting time in young and mid-aged Australian women: findings from the Australian Longitudinal Study for Women's Health

OBJECTIVE

To examine changes in sitting time (ST) in women over nine years and to identify associations between life events and these changes.

METHODS

Young (born 1973-78, n=5215) and mid-aged (born 1946-51, n=6973) women reported life events and ST in four surveys of the Australian Longitudinal Study on Women's Health between 2000 and 2010. Associations between life events and changes in ST between surveys (decreasers ≥2 h/day less, increasers ≥2 h/day more) were estimated using generalized estimating equations.

RESULTS

Against a background of complex changes there was an overall decrease in ST in young women (median change -0.48 h/day, interquartile range [IQR]=-2.54, 1.50) and an increase in ST in mid-aged women (median change 0.43 h/day; IQR=-1.29, 2.0) over nine years. In young women, returning to study and job loss were associated with increased ST, while having a baby, beginning work and decreased income were associated with decreased ST. In mid-aged women, changes at work were associated with increased ST, while retiring and decreased income were associated with decreased ST.

CONCLUSIONS

ST changed over nine years in young and mid-aged Australian women. The life events they experienced, particularly events related to work and family, were associated with these changes.

Weight Gain, Overweight, and Obesity: Determinants and Health Outcomes from the Australian Longitudinal Study on Women's Health

Recent estimates suggest that 35.3 % of adult Australians are overweight and a further 27.5 % are obese. The Australian Longitudinal Study on Women's Health (ALSWH) is a prospective study of women's health that commenced in Australia in 1996. The study recruited approximately 40,000 women in three birth cohorts, 1973-1978, 1946-1951 and 1921-1926, who have since been followed up approximately every three years using self-report surveys. Six surveys have been completed to date. This review aims to describe the changes in weight and weight status over time in the three ALSWH cohorts, and to review and summarise the published findings to date relating to the determinants and health consequences of weight gain, overweight and obesity. Future plans for the ALSWH include on-going surveys for all cohorts, with a seventh survey in 2013-2015, and establishment of a new cohort of women born in 1990-1995, which is currently being recruited.

Colorectal cancer survivors' exercise experiences and preferences: qualitative findings from an exercise rehabilitation programme immediately after chemotherapy

Little is known about cancer survivors' experiences with and preferences for exercise programmes offered during rehabilitation (immediately after cancer treatment). This study documented colorectal cancer survivors' experiences in an exercise rehabilitation programme and their preferences for programme content and delivery. At the completion of 12 weeks of supervised exercise, 10 participants took part in one-on-one semi-structured interviews. Data from these interviews were coded, and themes were identified using qualitative software. Key findings were that most participants experienced improvements in treatment symptoms, including reduced fatigue and increased energy and confidence to do activities of daily living. They also reported that interactions with the exercise trainer and a flexible programme delivery were important aspects of the intervention. Most participants reported that they preferred having a choice of exercise, starting to exercise within a month after completing treatment, having supervision and maintaining a one-on-one format. Frustrations included scheduling conflicts and a lack of a transition out of the programme. The findings indicate that colorectal cancers experience benefits from exercise offered immediately after treatment and prefer individual attention from exercise staff. They further indicate directions for the implementation of future exercise programmes with this population.

A systematic review of the association between physical activity and colorectal cancer risk

This review evaluated the strength of the evidence for a causal relationship between physical activity (PA) and colorectal cancer (CRC). A systematic review of databases through February 2008 was conducted to identify studies that assessed the association between total or recreational PA and incidence or mortality of CRC (including CRC, rectal cancer, colon cancer, and proximal or distal colon cancer). Studies were evaluated for significant associations between PA and risk of CRC endpoints and for evidence of dose-response relationships in the highest quality studies. Twenty cohort studies were evaluated; 11 were high-quality. Fifty percent of all studies and 64% of highest quality studies reported at least one significant association between PA and risk of a CRC endpoint (P<0.05). However, only 28% of all analyses (31% of analyses of highest quality studies) were significant (P<0.05). Only 40% of analyses of highest quality studies resulted in a significant P for trend (P<0.05); however, a non-significant inverse linear association between PA and colon cancer risk was apparent. Heterogeneity in the evidence from all studies and from the highest quality studies was evident. Evidence from cohort studies is not sufficient to claim a convincing relationship exists between PA and CRC risk.

Do walking and leisure-time physical activity protect against arthritis in older women?

OBJECTIVE

To examine the prospective dose-response relationships between both leisure-time physical activity (LTPA) and walking with self-reported arthritis in older women.

DESIGN, SETTING AND PARTICIPANTS

Data came from women aged 73-78 years who completed mailed surveys in 1999, 2002 and 2005 for the Australian Longitudinal Study on Women's Health. Women reported their weekly minutes of walking and moderate to vigorous physical activities. They also reported on whether they had been diagnosed with, or treated for, arthritis since the previous survey. General estimating equation analyses were performed to examine the longitudinal relationship between LTPA and arthritis and, for women who reported walking as their only physical activity, the longitudinal relationship between walking and arthritis. Women who reported arthritis or a limited ability to walk in 1999 were excluded, resulting in data from 3613 women eligible for inclusion in these analyses.

MAIN RESULTS

ORs for self-reported arthritis were lowest for women who reported "moderate" levels of LTPA (OR 0.78; 95% CI 0.67 to 0.92), equivalent to 75 to <150 minutes of moderate-intensity LTPA per week. Slightly higher odds ratios were found for women who reported "high" (OR 0.81; 95% CI 0.69 to 0.95) or "very high" (OR 0.84; 95% CI 0.72 to 0.98) LTPA levels, indicating no further benefit from increased activity. For women whose only activity was walking, an inverse dose-response relationship between walking and arthritis was seen.

CONCLUSIONS

The results support an inverse association between both LTPA and walking with self-reported arthritis over 6 years in older women who are able to walk.

Measurement properties of the CHAMPS physical activity questionnaire in a sample of older Australians

BACKGROUND

The effective evaluation of physical activity interventions for older adults requires measurement instruments with acceptable psychometric properties that are sufficiently sensitive to detect changes in this population.

AIM

To assess the measurement properties (reliability and validity) of the Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire in a sample of older Australians.

METHODS

CHAMPS data were collected from 167 older adults (mean age 79.1 S.D. 6.3 years) and validated with tests of physical ability and the SF-12 measures of physical and mental health. Responses from a sub-sample of 43 older adults were used to assess 1-week test-retest reliability.

RESULTS

Approximately 25% of participants needed assistance to complete the CHAMPS questionnaire. There were low but significant correlations between the CHAMPS scores and the physical performance measures (rho=0.14-0.32) and the physical health scale of the SF-12 (rho=0.12-0.24). Reliability coefficients were highest for moderate-intensity (ICC=0.81-0.88) and lowest for vigorous-intensity physical activity (ICC=0.34-0.45). Agreement between test-retest estimates of sufficient physical activity for health benefits (> or =150min and > or =5 sessions per week) was high (percent agreement=88% and Cohen's kappa=0.68).

CONCLUSION

These findings suggest that the CHAMPS questionnaire has acceptable measurement properties, and is therefore suitable for use among older Australian adults, as long as adequate assistance is provided during administration.

Sitting time and socio-economic differences in overweight and obesity

OBJECTIVES

To examine (1) the inter-relationships between socio-economic status (SES), physical activity, three different domains of sitting time (weekday, weekend day and leisure-time sitting), and being overweight or obese (body mass index>/=25 kg/m(2)); and (2) the potential mediation effects of sitting time in the relationship between socio-economic factors and being overweight or obese in working Australian adults.

DESIGN

Observational epidemiological study.

SUBJECTS

One thousand forty eight working adults. Using a multistage sampling design on neighbourhood SES, participants were from high and low SES neighbourhoods of an Australian capital city.

MEASUREMENTS

Neighbourhood SES was assessed using census data; individual SES was based on self-reported educational attainment and household income. There were three sitting time variables: sitting time on weekdays, weekend days and in leisure time. Overweight and obesity were determined using self-reported body weight and height.

RESULTS

Gender, age, neighbourhood SES, education, working hours and physical activity were independently associated with weekday, weekend day and leisure-related sitting time. With the exception of education and working hours, these variables were also independently associated with being overweight or obese. Leisure-time sitting was found to be a mediator in the relationships between gender, education and being overweight or obese.

CONCLUSION

Strategies to promote less sitting in leisure time are required to combat overweight and obesity in Australian adults, especially among those from low SES neighbourhoods, and among those with high levels of education and income who work long hours.

Weight gained in two years by a population of mid-aged women: how much is too much?

OBJECTIVE

To establish the prevalence of weight change in mid-aged women over a 2-year period, and to assess the relationship between weight change and physical and mental well-being (SF36) in order to begin debate about the need for quantified standards of weight gain.

DESIGN

Prospective study of weight change and well-being over a 2-year period among mid-aged women participating in a large national survey.

SUBJECTS

Seven thousand two hundred and seventy women without surgical menopause aged between 45 and 50 years (termed mid-aged), enrolled in the Australian Longitudinal Study on Women's Health.

MEASUREMENTS

Weight change (self-reported weight at two time points) and physical and mental well-being (SF-36) explored using linear regression, while adjusting for potential confounders.

RESULTS

Only half the women maintained their weight within 2.25 kg, and one-third gained more than this amount in a 2-year period. While weight gain (> or = 2.25 kg) was negatively associated with physical well-being, both weight loss and weight gain were associated with poorer mental well-being.

CONCLUSION

This is the first prospective study using a large, population-based cohort to demonstrate that small changes in weight are associated with changes in well-being in mid-aged Australian women. It provides further evidence of the need for public health messages to specify the actual amount that constitutes weight gain, but further research is needed to establish these standards for the entire population.

Promoting physical activity to older adults: A preliminary evaluation of three general practice-based strategies

The aim of this study was to explore the feasibility of an exercise scientist (ES) working in general practice to promote physical activity (PA) to 55 to 70 year old adults. Participants were randomised into one of three groups: either brief verbal and written advice from a general practitioner (GP) (G1, N=9): or individualised counselling and follow-up telephone calls from an ES, either with (G3, N=8) or without a pedometer (G2, N=11). PA levels were assessed at week 1, after the 12-wk intervention and again at 24 weeks. After the 12-wk intervention, the average increase in PA was 116 (SD=237) min/wk: N=28, p<0.001. Although there were no statistically significant between-group differences, the average increases in PA among G2 and G3 participants were 195 (SD=207) and 138 (SD=315) min/wk respectively, compared with no change (0.36, SD=157) in G1. After 24 weeks, average PA levels remained 56 (SD=129) min/wk higher than in week 1. The small numbers of participants in this feasibility study limit the power to detect significant differences between groups, but it would appear that individualised counselling and follow-up contact from an ES, with or without a pedometer, can result in substantial changes in PA levels. A larger study is now planned to confirm these findings.

Physical activity among Aboriginal and Torres Strait Islander people and communities

The epidemiological rationale for a focus on physical activity (PA) among Aboriginal and Torres Strait Islander (ATSI) people is compelling. PA programs have significant potential to benefit ATSI people and their communities through their contribution to reducing chronic disease, improving physical and mental health and well-being, and improving social factors such as community connectedness. Despite the powerful rationale for a focus on PA in ATSI communities, few published intervention studies have demonstrated the effectiveness of community strategies to promote increased PA among ATSI people. There are however, some examples of ongoing community programs in the 'grey' literature, which illustrate ongoing work in this domain. In view of the paucity of work in this area, there is an urgent need for (1) more research into the effectiveness of innovative strategies for increasing PA among ATSI people: (2) translation of effective strategies into dissemination trials; and (3) fast tracking of research in this area into the scientific literature.

Test-retest reliability of four physical activity measures used in population surveys

Accurate monitoring of prevalence and trends in population levels of physical activity (PA) is a fundamental public health need. Test-retest reliability (repeatability) was assessed in population samples for four self-report PA measures: the Active Australia survey (AA, N=356), the short International Physical Activity Questionnaire (IPAQ, N=104), the physical activity items in the Behavioral Risk Factor Surveillance System (BRFSS, N=127) and in the Australian National Health Survey (NHS, N=122). Percent agreement and Kappa statistics were used to assess reliability of classification of activity status as 'active', 'insufficiently active' or 'sedentary'. Intraclass correlations (ICCs) were used to assess agreement on minutes of activity reported for each item of each survey and for total minutes. Percent agreement scores for activity status were very good on all four instruments, ranging from 60% for the NHS to 79% for the IPAQ. Corresponding Kappa statistics ranged from 0.40 (NHS) to 0.52 (AA). For individual items, ICCs were highest for walking (0.45 to 0.78) and vigorous activity (0.22 to 0.64) and lowest for the moderate questions (0.16 to 0.44). All four measures provide acceptable levels of test-retest reliability for assessing both activity status and sedentariness, and moderate reliability for assessing total minutes of activity.

Updating the evidence relating to physical activity intervention studies in older people

For older adults, physical activity (PA) plays a central role in the prevention and management of chronic disease, and has the potential to reduce physical decline, maintain functional ability and prevent injuries. This review provides an update of the evidence relating to the effectiveness of PA intervention studies (both general PA and trials specific to progressive resistance training (PRT)) for older adults. The following electronic databases were searched for articles published since 1999: Medline, PubMed, EMBASE, CINAHL and Sport Discus. For the PRT section, a 2002 Cochrane review was also used. Eight general PA intervention studies were included in this review, ranging from one-on-one counselling in general practice to the community-wide promotion of walking. The aim of most of the trials was to increase moderate and/or vigorous activity levels. Most of the studies reviewed had some degree of success in getting older people to be more active. However, a major limitation was the use of self-report measures of PA. The review of PRT interventions included 21 trials. Participants in half the studies had either functional limitations or a chronic condition. Most trials were conducted in a supervised setting using specialised equipment. Increased strength and improvement in basic functional tasks were generally reported, but there was a paucity of strong evidence linking PRT with reduced physical disability and improved health-related quality of life. While considerable progress is being made in this area, further population-based studies that include home and whole-community interventions are required.

Sitting time and work patterns as indicators of overweight and obesity in Australian adults

BACKGROUND

Increasing levels of physical inactivity and sedentariness are contributing to the current overweight and obesity epidemic. In this paper, the findings of two recent studies are used to explore the relationships between sitting time (in transport, work and leisure), physical activity and body mass index (BMI) in two contrasting samples of adult Australians.

METHODS

Data on sitting time, physical activity, BMI and a number of demographic characteristics were compared for participants in two studies-529 women who were participants in a preschool health promotion project ('mothers'), and 185 men and women who were involved in a workplace pedometer study ('workers'). Relationships between age, number of children, physical activity, sitting time, BMI, gender and work patterns were explored. Logistic regression was used to predict the likelihood of being overweight or obese, among participants with different physical activity, sitting time and work patterns.

RESULTS

The total reported time spent sitting per day (across all domains) was almost 6 h less among the mothers than the workers (P<0.001), and compared with the mothers, a significantly greater proportion of the workers was classified as overweight or obese (BMI > or =25 kg/m(2)). Univariate analysis found that, compared with men in full-time work, women who worked full-time (OR=0.42, CI: 0.24-0.74), part-time (OR=0.35, CI: 0.20-0.59) or in full-time home duties (OR=0.51, CI: 0.29-0.88) were about half as likely to be overweight or obese. Participants who reported high daily levels of sitting (> or =7.4 h) were also significantly more likely than those who reported 'low' levels (<4.7 h/day) to be overweight or obese (OR=1.68, CI: 1.16-2.42). Multivariate analysis (including physical activity, work patterns and sitting time) confirmed that full-time and part-time working women (but not 'home duties' women) were less likely to report BMI > or =25 kg/m(2) than full-time working men (full-time: OR=0.44, CI: 0.25-0.78; part-time: OR=0.45, CI: 0.24-0.86), but the OR for BMI > or =25 among those in the high sitting category was attenuated (OR=1.61, CI 0.96-2.71).

CONCLUSIONS

The findings suggest a need for inclusion of measures of both activity and inactivity in future studies, so that the complex relationships between these behavioural determinants of BMI can be clarified.

Chlamydial antigens colocalize within IncA-laden fibers extending from the inclusion membrane into the host cytosol

Chlamydial IncA localizes to the inclusion membrane and to vesicular fibers extending away from the inclusion. Chlamydial outer membrane components, in the absence of developmental forms, are found within these fibers. This colocalization may explain how chlamydial developmental form antigens are localized outside of the inclusion within infected cells.

Inhibition of transferrin recycling and endosome tubulation by phospholipase A2 antagonists

We report here that a broad spectrum of phospholipase A(2) (PLA(2)) antagonists produce a concentration-dependent, differential block in the endocytic recycling pathway of transferrin (Tf) and Tf receptors (TfRs) but have no acute affect on Tf uptake from the cell surface. At low concentrations of antagonists (approximately 1 microm), Tf and TfR accumulated in centrally located recycling endosomes, whereas at higher concentrations (approximately 10 microm), Tf-TfR accumulated in peripheral sorting endosomes. Several independent lines of evidence suggest that this inhibition of recycling may result from the inhibition of tubule formation. First, BFA-stimulated endosome tubule formation was similarly inhibited by PLA(2) antagonists. Second, endocytosed tracers were found in larger spherical endosomes in the presence of PLA(2) antagonists. And third, endosome tubule formation in a cell-free, cytosol-dependent reconstitution system was equally sensitive PLA(2) antagonists. These results are consistent with the conclusion that endosome membrane tubules are formed by the action of a cytoplasmic PLA(2) and that PLA(2)-dependent tubules are involved in intracellular recycling of Tf and TfR. When taken together with previous studies on the Golgi complex, these results also indicate that an intracellular PLA(2) activity provides a novel molecular mechanism for inducing tubule formation from multiple organelles.

Too wet to exercise? Leaking urine as a barrier to physical activity in women

Leaking urine is frequently mentioned (anecdotally) by women as a barrier to physical activity. The aim of this paper was to use results from the Australian Longitudinal Study on Women's Health (ALSWH) to explore the prevalence of leaking urine in Australian women, and to ascertain whether leaking urine might be a barrier to participation for women. More than 41,000 women participated in the baseline surveys of the ALSWH in 1996. More than one third of the mid-age (45-50 years) and older (70-75) women and 13% of the young women (18-23) reported leaking urine. There was a cross-sectional association between leaking urine and physical activity, such that women with more frequent urinary leakage were also more likely to report low levels of physical activity. More than one thousand of those who reported leaking urine at baseline participated in a follow-up study in 1999. Of these, more than 40% of the mid-age women (who were aged 48-53 in 1999), and one in seven of the younger (21-26 years) and older (73-79 years) women reported leaking urine during sport or exercise. More than one third of the mid-age women and more than one quarter of the older women, but only 7% of the younger women said they avoided sporting activities because of leaking urine. The data are highly suggestive that leaking urine may be a barrier to physical activity, especially among mid-age women. As current estimates suggest that fewer than half of all Australian women are adequately active for health benefit, health professionals could be more proactive in raising this issue with women and offering help through non-invasive strategies such as pelvic floor muscle exercises.

Dietary treatment of iron deficiency in women of childbearing age

BACKGROUND

The Australian Iron Status Advisory Panel advocates dietary intervention as the first treatment option for mild iron deficiency [serum ferritin (SF) = 10-15 microg/L]. However, there appear to be no studies on the efficacy of dietary treatment for iron deficiency.

OBJECTIVE

We compared the effects of iron supplementation and of a high-iron diet on serum ferritin (SF) and hemoglobin in iron-deficient women of childbearing age.

DESIGN

Forty-four iron-deficient women (SF <15 microg/L or SF = 15-20 microg/L plus serum iron <10 micromol/L and total-iron-binding capacity >68 micromol/L) and 22 iron-replete women (hemoglobin > or =120 g/L and SF >20 microg/L) matched for age and parity categories were enrolled and completed 7-d weighed food records at baseline. The iron-deficient women were randomly allocated to receive iron supplementation (105 mg/d; supplement group) or a high-iron diet (recommended intake of absorbable iron: 2.25 mg/d; diet group) for 12 wk. Hematologic and dietary assessments were repeated at the end of the intervention and again after a 6-mo follow-up.

RESULTS

Mean SF in the supplement group increased from 9.0 +/- 3.9 microg/L at baseline to 24.8 +/- 10.0 microg/L after the intervention and remained stable during follow-up (24.2 +/- 9.8 microg/L), whereas the diet group had smaller increases during the intervention (8.9 +/- 3.1 to 11.0 +/- 5.9 microg/L) but continued to improve during follow-up (to 15.2 +/- 9.5 microg/L). Mean hemoglobin tended to improve in both intervention groups, but the change was only significant in the supplement group.

CONCLUSIONS

In iron-deficient women of childbearing age, a high-iron diet produced smaller increases in SF than did iron supplementation but resulted in continued improvements in iron status during a 6-mo. follow-up.

Dietary and supplement treatment of iron deficiency results in improvements in general health and fatigue in Australian women of childbearing age

OBJECTIVE

To examine the effects of iron deficiency and its treatment by iron supplementation or a high iron diet on fatigue and general health measures in women of childbearing age.

DESIGN

Randomised controlled trial to compare supplement and dietary treatment of iron deficiency.

SUBJECTS

44 iron deficient (serum ferritin < 15 microg/L or serum ferritin 15-20 microg/L, plus two of the following: serum iron < 10 micromol/L, total iron binding capacity > 68 micromol/L or transferrin saturation < 15%) and 22 iron replete (hemoglobin > or = 10 g/L and serum ferritin > 20 microg/L) women 18 to 50 years of age were matched for age and parity.

INTERVENTIONS

Iron deficient women were randomly allocated to either iron supplementation or a high iron diet for 12 weeks.

MEASURES OF OUTCOME

Iron deficient and iron replete participants had iron studies performed and completed the Piper Fatigue Scale (PFS) and the SF-36 general health and well-being questionnaire at baseline (T0), following the 12 week intervention (T1) and again after a six-month non-intervention phase (T2). The SF-36 includes measures of physical (PCS) and mental (MCS) health and vitality (VT).

RESULTS

MCS and VT scores were lower and PFS scores were higher for iron deficient women (diet and supplement groups) than iron replete women at baseline. Both intervention groups showed similar improvements in MCS, VT and PFS scores during the intervention phase, but mean increases in serum ferritin were greater in the supplement than the diet group. PCS scores were not related to iron status.

CONCLUSIONS

Treatment of iron deficiency with either supplementation or a high iron diet results in improved mental health and decreased fatigue among women of childbearing age.

Polarization instabilities in a two-photon laser

We describe the operating characteristics of a new type of quantum oscillator that is based on a two-photon stimulated emission process. This two-photon laser consists of spin-polarized and laser-driven 39K atoms placed in a high-finesse transverse-mode-degenerate optical resonator and produces a beam with a power of approximately 0.2 microW at a wavelength of 770 nm. We observe complex dynamical instabilities of the state of polarization of the two-photon laser, which are made possible by the atomic Zeeman degeneracy. We conjecture that the laser could emit polarization-entangled twin beams if this degeneracy is lifted.

Immunoperoxidase methods for localization of antigens in cultured cells and tissues

This carefully written unit describes two methods for using the immunoperoxidase reaction to localize antigens at the electron microscope level; one for adherent cultured cells and one for tissue sections. The reaction conditions are first optimized at the light microscope level and then adapted for EM level observation. These methods allow for reliable detection of antigens at the cell surface, within the cell, and especially in membrane bounded organelles. Embedding and staining procedures are also optimized for sample visualization.

Iron deficiency, general health and fatigue: results from the Australian Longitudinal Study on Women's Health

Associations between self-reported 'low iron', general health and well-being, vitality and tiredness in women, were examined using physical (PCS) and mental (MCS) component summary and vitality (VT) scores from the MOS short-form survey (SF-36). 14,762 young (18-23 years) and 14,072 mid-age (45-50 years) women, randomly selected from the national health insurance commission (Medicare) database, completed a baseline mailed self-report questionnaire and 12,328 mid-age women completed a follow-up questionnaire 2 years later. Young and mid-age women who reported (ever) having had 'low iron' reported significantly lower mean PCS, MCS and VT scores, and greater prevalence of 'constant tiredness' at baseline than women with no history of iron deficiency [Differences: young PCS = -2.2, MCS = -4.8, VT = -8.7; constant tiredness: 67% vs. 45%; mid-age PCS = -1.4, MCS = -3.1, VT = -5.9; constant tiredness: 63% vs. 48%]. After adjusting for number of children, chronic conditions, symptoms and sociodemographic variables, mean PCS, MCS and VT scores for mid-age women at follow-up were significantly lower for women who reported recent iron deficiency (in the last 2 years) than for women who reported past iron deficiency or no history of iron deficiency [Means: PCS--recent = 46.6, past = 47.8, never = 47.7; MCS--recent = 45.4, past = 46.9, never = 47.4; VT--recent = 54.8, past = 57.6, never = 58.6]. The adjusted mean change in PCS, MCS and VT scores between baseline and follow-up were also significantly lower among mid-age women who reported iron deficiency only in the last 2 years (i.e. recent iron deficiency) [Mean change: PCS = -3.2; MCS = -2.1; VT = -4.2]. The results suggest that iron deficiency is associated with decreased general health and well-being and increased fatigue.

The Anti Cancer Council of Victoria FFQ: relative validity of nutrient intakes compared with weighed food records in young to middle-aged women in a study of iron supplementation

OBJECTIVE

To assess the validity of the Anti Cancer Council of Victoria food frequency questionnaire (ACCVFFQ) relative to seven-day weighed food records (WFRs) in 63 women of child-bearing age.

METHOD

63 women completed WFRs to assess iron intake as part of a study on iron deficiency. These women also completed the ACCVFFQ. Nutrient intakes were computed independently for the WFRs and FFQs. Intakes were compared as group means, by correlation and by quintile classification, adjusting for day-to-day variation in intakes, and for energy intake. Individual differences in results were also examined.

RESULTS

The strongest associations between WFR and FFQ results were energy-adjusted, log-transformed and adjusted for day-to-day variability in intake. Correlation coefficients ranged from 0.28 for vitamin A to 0.78 for carbohydrate. Mean intakes from the WFRs and FFQs were within +/- 20% for 21 of 27 nutrients. Poor agreement between FFQs and WFRs for retinol intake was due to the inclusion of liver in two WFRs, an item which is not included in the FFQ.

CONCLUSION

The ACCVFFQ performs as well as other FFQs for which validation data are available. The relatively poor measurement of retinol is consistent with other data, and with the limited number of foods in which this nutrient is abundant.

IMPLICATIONS

The availability of an optically scannable valid instrument for assessing dietary intake will facilitate epidemiological studies of diet and disease, an area of current research priority.

Relationships between body mass index and well-being in young Australian women

OBJECTIVE

To explore relationships between body mass index (BMI, kg/m2) and indicators of health and well-being in young Australian women.

DESIGN

Population based cohort study--baseline cross sectional data.

SUBJECTS

14,779 women aged 18-23 who participated in the baseline survey of the Australian Longitudinal Study on Women's Health in 1996.

MEASUREMENTS

Self-reported height, weight, medical conditions, symptoms and SF-36.

RESULTS

The majority of women (68%) had a BMI in the range 18.5- <25; 12% had a BMI <18.5; 14% had a BMI in the range 25- <30 and 6% had a BMI > or =30. After adjustment for area of residence, age, education, smoking and exercise, women in the highest BMI category (> or =30) were more likely to report hypertension, asthma, headaches, back pain, sleeping difficulties, irregular periods, and more visits to their medical practitioner. They were also more likely to have given birth at least once, and less likely to report 'low iron'. Women with low BMI (<18.5) were more likely to report irregular periods and 'low iron'. Mean scores on the SF-36 sub-scales for physical functioning, general health and vitality were highest for women with BMI in the range 18.5-25.

CONCLUSION

Acknowledging the limits of the cross-sectional nature of the data, the results show that the deleterious effects of overweight can be seen at a comparatively young age, and that BMI <25 is associated with fewer indicators of morbidity in young women. However, as BMI <18.5 is associated with low iron and irregular periods, care should be taken when developing strategies to prevent overweight in young women, not to encourage women with healthy weight to strive for a lower BMI.

Comparison of estimates of population levels of physical activity using two measures

OBJECTIVE

To compare estimates of population levels of 'adequate activity' for health benefit in different age and sex groups using two different measures--kilocalories (kcals) and Mets.mins.

METHODS

10,464 mid-age women (47-52 years) from the second survey of the Australian Longitudinal Study on Women's Health (ALSWH, 1998) and 2,500 men and women (18-75 years) from the 1997 Active Australia national survey, answered questions about physical activity. Kcals and Mets.mins were calculated from self-reported time spent in walking, moderate and vigorous activity, and self-reported body weight. 'Adequate activity' was defined as a minimum of 800 kcals or 600 Mets.mins.

RESULTS

There were differences in the estimates of 'adequate activity' using the two methods among women participants in both surveys, but not among the male participants in the Active Australia survey. A significant proportion of the women in both surveys (6.4% of the ALSWH women and 8.5% of the Active Australia women, mean weight 60 kg) were classified as 'inactive' when the kcals method was used despite reporting levels of activity commensurate with good health. Fewer than 1% (mean weight 105 kg) were classified as 'active' using kcals when reporting lower than recommended levels of activity. Agreement between the two methods was better among men; only 3% were misclassified because of low or very high weight.

CONCLUSIONS

The Mets.mins method of estimating 'adequate' activity assesses physical activity independently of body weight and is recommended for use in future population surveys, as it is less likely to under-estimate the prevalence of physical activity in women.

IMPLICATIONS

Women and men aged 45-59 and women aged > 60 should be the target of specific health promotion strategies to increase population levels of physical activity.

Yersinia enterocolitica infection in children

BACKGROUND

Yersinia enterocolitica can cause illness ranging from self-limited enteritis to life-threatening systemic infection. The present study was undertaken to review the epidemiology, clinical manifestations, complications and outcome of Y. enterocolitica enteritis in children seen at a large children's hospital.

METHODS

The project consisted of a retrospective chart review of medical and microbiologic records of all children with stool cultures positive for Y. enterocolitica during a 7-year period.

RESULTS

The review included 142 patients with Y. enterocolitica enteritis. Patients' ages ranged from 18 days to 12 years, and the majority (85%) were younger than 1 year. Most patients presented during November, December and January. History of exposure to chitterlings (raw pork intestines) at home was elicited in 25 of 30 cases. Y. enterocolitica accounted for 12.6% (142 of 1,120) of all bacterial intestinal pathogens isolated during the study period. Blood cultures were positive in 7(9%) of 78 patients; 6 were younger than 1 year and one 12-year-old had sickle cell disease. Of 132 isolates tested all were susceptible to trimethoprim-sulfamethoxazole, tobramycin and gentamicin; the majority were susceptible to cefotaxime (99%), ceftazidime (89%) and cefuroxime (88%). All bacteremic patients responded to cefotaxime treatment. Follow-up evaluation of 40 ambulatory patients revealed no difference in clinical improvement between those treated with oral trimethoprim-sulfamethoxazole (17 of 23) and those who were not treated (8 of 17) (P = 0.1).

CONCLUSION

Y. enterocolitica is an important cause of enteritis in our young patient population during the winter holidays. Exposure of infants to chitterlings appears to be a risk factor. Infants younger than 3 months are at increased risk for bacteremia. Cefotaxime is effective in the treatment of Y. enterocolitica bacteremia; however, the role of oral antibiotics in the management of enteritis needs further evaluation.

Leisure time physical activity in Australian women: relationship with well being and symptoms

This paper explores the association between moderate levels of physical activity (PA) and health benefits in well being and symptoms such as tiredness, back pain, and constipation. Participants in the Australian Longitudinal Study on Women's Health, 14,502 young women (ages 18-23 years), 13,609 middle-age women (45-50 years), and 11,421 older women (ages 70-75 years), answered questions about vigorous and less vigorous exercise (used to determine a physical activity score), well being (SF-36), symptoms, and medical conditions. There were significant associations between the PA score and SF-36 in each cohort. Odds ratios (OR) for a range of symptoms and conditions were lower for women who reported low to moderate activity than for sedentary women, for example, for young women or for constipation = 0.76 (CI, 0.65-0.89), for middle-age women or for tiredness = 0.70 (0.63-0.78). There was no threshold of PA at which health benefits increased significantly. Although cross-sectional, the findings suggest that low-to-moderate levels of exercise are associated with a range of health benefits for women of all ages. These preliminary findings will be followed up during the longitudinal study.

Clofibrate inhibits membrane trafficking to the Golgi complex and induces its retrograde movement to the endoplasmic reticulum

Insights into the function of the Golgi complex have been provided by experiments performed with various inhibitors of membrane trafficking, such as the macrocyclic lactone brefeldin A (BFA), a compound that inhibits constitutive secretion, prevents the formation of coatomer-coated transport vesicles, and stimulates the retrograde movement of Golgi resident enzymes back to the ER. We show here that the structurally unrelated compound clofibrate, a peroxisome proliferator (PP) and hypolipidemic agent, also reversibly disrupts the morphological and functional integrity of the Golgi complex in a manner similar to BFA. In the presence of clofibrate, the forward transport of newly synthesized secretory proteins from the ER to the Golgi is dramatically inhibited. Moreover, clofibrate causes Golgi membranes to travel rapidly in a microtubule-dependent manner back to the ER, forming a hybrid ER-Golgi tubulovesicular membrane network. These affects appear to be independent of clofibrate's ability to stimulate the PP-activated receptor (PPAR) alpha pathway because other PPAR stimulators (DEHP, WY-14643) did not alter the Golgi complex or induce retrograde trafficking. These data suggest that PPAR alpha-independent, clofibrate-sensitive proteins participate in regulating Golgi-to-ER retrograde membrane transport, and, equally importantly, that clofibrate may be used as a pharmacological tool for investigating Golgi membrane dynamics.

Phospholipase A2 antagonists inhibit constitutive retrograde membrane traffic to the endoplasmic reticulum

Eukaryotic cells contain a variety of cytoplasmic Ca(2+)-dependent and Ca(2+)-independent phospholipase A2s (PLA2s; EC 2.3.1.2.3). However, the physiological roles for many of these ubiquitously-expressed enzymes is unclear or not known. Recently, pharmacological studies have suggested a role for Ca(2+)-independent PLA2 (iPLA2) enzymes in governing intracellular membrane trafficking events in general and regulating brefeldin A (BFA)-stimulated membrane tubulation and Golgi-to-endoplasmic reticulum (ER) retrograde membrane trafficking, in particular. Here, we extend these studies to show that membrane-permeant iPLA2 antagonists potently inhibit the normal, constitutive retrograde membrane trafficking from the trans-Golgi network (TGN), Golgi complex, and the ERGIC-53-positive ER-Golgi-intermediate compartment (ERGIC), which occurs in the absence of BFA. Taken together, these results suggest that iPLA2 enzymes play a general role in regulating, or directly mediating, multiple mammalian membrane trafficking events.

Patterns of alcohol consumption in young Australian women: socio-demographic factors, health-related behaviours and physical health

OBJECTIVE

To determine which socio-demographic factors, health-related behaviours and physical health conditions are associated with non-drinking, binge drinking and hazardous/harmful drinking in young Australian women.

METHODS

Cross-sectional data were obtained from the baseline survey of 14,762 young women (aged 18-23 years) enrolled in the Women's Health Australia study in 1996. Associations between a range of drinking patterns and socio-demographic factors, health-related behaviours and health conditions were examined.

RESULTS

Half the women were 'low intake' drinkers, a third 'rarely drank' and 9% were non-drinkers; however, 70% reported binge drinking with one-quarter of the binge drinkers doing so at least weekly. Non-drinkers were more likely than drinkers to be married, pregnant, non-smokers, born in non-English speaking countries, to live in the Northern Territory, and to have lower levels of education, employment, and private health insurance. 'Low intake/binge weekly' drinkers (12%) and 'hazardous/harmful' drinkers (5%) were more likely than 'low risk' drinkers to be unmarried; to live in shared accommodation, alone or with their parents; to live in rural or remote areas; to have ever had any sexually transmitted infection; to be current smokers or ex-smokers and to have used unhealthy weight-control practices.

CONCLUSIONS

The results confirm findings from other countries about the importance of social conditions as determinants of alcohol consumption by young women.

IMPLICATIONS

Health promotion to reduce young women's alcohol consumption needs to be carefully targeted to take account of their demographies, living environments and beliefs.

A secondary structure motif predictive of protein localization to the chlamydial inclusion membrane

Chlamydiae are obligate intracellular pathogens that spend their entire growth phase sequestered in a membrane-bound vacuole called an inclusion. A set of chlamydial proteins, labelled Inc proteins, has been identified in the inclusion membrane (IM). The predicted IncA, IncB and IncC amino acid sequences share very limited similarity, but a common hydrophobicity motif is present within each Inc protein. In an effort to identify a relatively complete catalogue of Chlamydia trachomatis proteins present in the IM of infected cells, we have screened the genome for open reading frames encoding this structural motif. Hydropathy plot analysis was used to screen each translated open reading frame in the C. trachomatis genome database. Forty-six candidate IM proteins (C-lncs) that satisfied the criteria of containing a bilobed hydrophobic domain of at least 50 amino acids were identified. The genome of Chlamydia pneumoniae encodes a larger collection of C-lnc proteins, and only approximately half of the C-lncs are encoded within both genomes. In order to confirm the hydropathy plot screening method as a valid predictor of C-lncs, antisera and/or monoclonal antibodies were prepared against six of the C. trachomatis C-lncs. Immunofluorescence microscopy of C. trachomatis-infected cells probed with these antibodies showed that five out of six C-lncs are present in the chlamydial IM. Antisera were also produced against C. pneumoniae p186, a protein sharing identity with Chlamydia psittaci lncA and carrying a similar bilobed hydrophobic domain. These antisera labelled the inclusion membrane in C. pneumoniae infected cells, confirming that proteins sharing the unique secondary structural characteristic also localize to the inclusion membrane of C. pneumoniae. Sera from patients with high-titre antibodies to C. trachomatis were examined for reactivity with each tested C-lnc protein. Three out of six tested C-lncs were recognized by a majority of these patient sera. Collectively, these studies identify and characterize novel proteins localized to the chlamydial IM and demonstrate the existence of a potential secondary structural targeting motif for localization of chlamydial proteins to this unique intracellular environment.

Identification of an antigen localized to an apparent septum within dividing chlamydiae

The process of chlamydial cell division has not been thoroughly investigated. The lack of detectable peptidoglycan and the absence of an FtsZ homolog within chlamydiae suggest an unusual mechanism for the division process. Our laboratory has identified an antigen (SEP antigen) localized to a ring-like structure at the apparent septum within dividing chlamydial reticulate bodies (RB). Antisera directed against SEP show similar patterns of antigen distribution in Chlamydia trachomatis and Chlamydia psittaci RB. In contrast to localization in RB, SEP in elementary bodies appears diffuse and irregular, suggesting that the distribution of the antigen is developmental-stage specific. Treatment of chlamydiae with inhibitors of peptidoglycan synthesis or culture of chlamydiae in medium lacking tryptophan leads to the formation of nondividing, aberrant RB. Staining of aberrant RB with anti-SEP reveals a marked redistribution of the antigen. Within C. trachomatis-infected cells, ampicillin treatment leads to high levels of SEP accumulation at the periphery of aberrant RB, while in C. psittaci, treatment causes SEP to localize to distinct punctate sites within the bacteria. Aberrancy produced via tryptophan depletion results in a different pattern of SEP distribution. In either case, the reversal of aberrant formation results in the production of normal RB and a redistribution of SEP to the apparent plane of bacterial division. Collectively these studies identify a unique chlamydial-genus-common and developmental-stage-specific antigen that may be associated with RB division.

Synergistic effects of Candida and Escherichia coli on gut barrier function

BACKGROUND

Disruption of the indigenous gut microflora with overgrowth of gram-negative bacteria and Candida species is common in the critically ill patient. These organisms readily translocate in vitro, which may cause septic complications and organ failure. A synergistic effect between Escherichia coli and C. albicans in polymicrobial infections has been demonstrated. An interaction between these organisms at the mucosal barrier is unknown.

METHODS

Ca(CO2) monolayers were grown to confluence in a two compartment culture system. E. coli and C. albicans or E. coli alone were added to the apical chambers. Secretory immunoglobulin A was added to half of the apical chambers as well. Cell cultures were incubated for a total of 240 minutes. Basal media were sampled at timed intervals for quantitative culture. Monolayer integrity was confirmed by serial measurement of transepithelial electrical resistance.

RESULTS

Secretory immunoglobulin A decreased bacterial translocation across Ca(CO2) monolayers challenged with E. coli alone. Transepithelial passage of E. coli was significantly increased by coculture of bacteria with C. albicans. Augmentation of bacterial translocation by Candida occurred even in the presence of secretory immunoglobulin A.

CONCLUSIONS

Candida colonization of the GI tract may impair mucosal barrier defense against gram-negative bacteria. The clinical role of gut antifungal prophylaxis in protecting against gut derived gram-negative sepsis is speculative.

Phospholipase A(2) antagonists inhibit nocodazole-induced Golgi ministack formation: evidence of an ER intermediate and constitutive cycling

Evidence has been presented both for and against obligate retrograde movement of resident Golgi proteins through the endoplasmic reticulum (ER) during nocodazole-induced Golgi ministack formation. Here, we studied the nocodazole-induced formation of ministacks using phospholipase A(2) (PLA(2)) antagonists, which have been shown previously to inhibit brefeldin A-stimulated Golgi-to-ER retrograde transport. Examination of clone 9 rat hepatocytes by immunofluorescence and immunoelectron microscopy revealed that a subset of PLA(2) antagonists prevented nocodazole-induced ministack formation by inhibiting two different trafficking pathways for resident Golgi enzymes; at 25 microM, retrograde Golgi-to-ER transport was inhibited, whereas at 5 microM, Golgi-to-ER trafficking was permitted, but resident Golgi enzymes accumulated in the ER. Moreover, resident Golgi enzymes gradually redistributed from the juxtanuclear Golgi or Golgi ministacks to the ER in cells treated with these PLA(2) antagonists alone. Not only was ER-to-Golgi transport of resident Golgi enzymes inhibited in cells treated with these PLA(2) antagonists, but transport of the vesicular stomatitis virus G protein out of the ER was also prevented. These results support a model of obligate retrograde recycling of Golgi resident enzymes during nocodazole-induced ministack formation and provide additional evidence that resident Golgi enzymes slowly and constitutively cycle between the Golgi and ER.

Stimulation of Golgi membrane tubulation and retrograde trafficking to the ER by phospholipase A(2) activating protein (PLAP) peptide

Recent pharmacological studies using specific antagonists of phospholipase A(2) (PLA(2)) activity have suggested that the formation of Golgi membrane tubules, 60-80 nm in diameter and up to several microns long, both in vivo and in a cell-free cytosol-dependent reconstitution system, requires the activity of a cytoplasmic Ca(2+)-independent PLA(2). We confirm and extend these studies by demonstrating that the stimulators of PLA(2), melittin and PLA(2) activating protein peptide (PLAPp), enhance cytosol-dependent Golgi membrane tubulation. Starting with preparations of bovine brain cytosol (BBC), or a fraction of BBC that is highly enriched in tubulation activity, called the gel filtration (GF) fraction, that are at subsaturating concentrations for inducing tubulation in vitro, we found that increasing concentrations of melittin or PLAPp produced a linear and saturable stimulation of Golgi membrane tubulation. This stimulation was inhibited by cytosolic PLA(2) antagonists, including the Ca(2+)-independent PLA(2)-specific antagonist, bromoenol lactone. The stimulatory effect of PLAPp, and its inhibition by PLA(2) antagonists, was reproduced using a permeabilized cell system, which reconstitutes both cytosol-dependent Golgi membrane tubulation and retrograde trafficking to the endoplasmic reticulum (ER). Taken together, these results are consistent with the idea that cytosolic PLA(2) activity is involved in the formation of Golgi membrane tubules, which can serve as trafficking intermediates in Golgi-to-ER retrograde movement.

Evaluation of Acinetobacter baumannii infection and colonization, and antimicrobial treatment patterns in an urban teaching hospital

In 1990 there was a sudden increase in the incidence of colonization and infection due to Acinetobacter baumannii (AB) in our intensive care units (ICUs). The isolates were multiply resistant to beta-lactam and aminoglycoside antibiotics, but remained susceptible to imipenem, amikacin, and ampicillin-sulbactam. We examined the frequency of infection and colonization with AB and the effects of increased imipenem and amikacin therapy on Pseudomonas aeruginosa. We also used disease-matched controls to determine the clinical and financial impacts of treating colonization. All patients with at least one AB isolate from January-December 1992 were identified retrospectively and classified as infected or colonized based on published Centers for Disease Control criteria; the control group was selected from a computerized medical records data base matching primary diagnostic codes (102 patients both groups). The 102 patients yielded 140 isolates, 124 resistant AB and 16 sensitive AB. Thirty three patients were infected, 69 colonized. Mortality correlated with APACHE II scores. Patients acquired the organism approximately 2 weeks after admission; they had a mean ICU stay of 27.35 days, compared with 5.53 days for controls. Patients with positive AB cultures required significantly more use of ventilators than those with negative AB cultures. They also had significantly longer hospital stay, more bed transfers, greater duration and number of antibiotics, and higher hospital and pharmacy charges. Unnecessary treatment for colonization with either imipenem or amikacin resulted in a substantial decrease of P. aeruginosa susceptibility to each agent. The financial impact of treating colonization was significant and is a potential area for cost avoidance. Our results emphasize the need to extubate and move patients to non-ICU beds as soon as possible to decrease the risk of nosocomial infection. It also highlights the need to avoid treating colonization, thus avoiding unnecessary antibiotic therapy.

Tyranny of distance? The health of mid-age women living in five geographical areas of Australia

Over 14,000 women aged 45-50 are participating in the Australian Longitudinal Study on Women's Health, which is designed to track the health of Australian women for 20 years, and to understand lifestyle and healthcare factors that influence women's health. The study deliberately overrepresents women from rural and remote areas. This analysis of baseline data from the study compares the responses of women living in urban areas (capital city, other metropolitan), large rural centres, small rural centres, other rural areas and remote areas (remote centres, other remote areas) of Australia. The data show that while women in this age group who live in rural and remote areas have similar levels of self-rated health, they have significantly fewer visits to general practitioners and specialists (P < 0.001) and more visits to alternative healthcare providers than women living in urban areas. Rural and remote area women were also more likely to undergo gynaecological surgery than women living in urban areas (P < 0.001). Other results suggest that being overweight is more common among women from rural and remote areas, and that these women also report lower levels of stress than women from urban areas (P < 0.001). Further follow up will allow any divergence in health and healthcare equity to be explored as these women get older.

Leaking urine in Australian women: prevalence and associated conditions

The paper aims to (1) assess the prevalence of leaking urine and to (2) explore associations between leaking urine and a variety of other symptoms, conditions, surgical procedures and life events in three large cohorts of Australian women, who are participants in the Australian Longitudinal Study on Women's Health. Young women aged 18-23 (N = 14,000), mid-age women, 45-50 (N = 13,738) and older women, 70-75 (N = 12,417), were recruited randomly from the national HIC/Medicare database. Leaking urine was reported by approximately one in eight young women [estimated prevalence 12.8% (95% CI: 12.2-13.3)] and one in three mid-age women [36.1% (CI: 35.2-37.0)] and older women [35.0% (CI: 34.1-35.9)]. Leaking urine was significantly associated with parity, conditions which increase the pressure on the pelvic floor such as constipation and obesity, past gynecological surgery and conditions which can impact on bladder control. The study showed that fewer than half the women had sought help for the problem and that younger women were less likely to be satisfied with the help available for this problem. Strategies for continence promotion, including opportunistic raising of the issue at the time of cervical screening and pregnancy care are suggested, so that the health and social outcomes of untreated chronic incontinence in women might be improved.