Small for gestational age and anthropometric body composition from early childhood to adulthood: the Aboriginal Birth Cohort study

Background

In Australia the estimated rate of small for gestational age (SGA) births is 9% among non-Indigenous births compared to 14% among Aboriginal and Torres Strait Islanders. There is limited research investigating the effect of being born SGA on body composition later in life in Indigenous Australians.

Methods

Using data from the Aboriginal Birth Cohort longitudinal study, we compared the body composition of those born SGA to non-SGA by analysing anthropometric measures (height, weight, waist circumference, fat percentage [FAT%], body mass index [BMI], waist-to-height ratio, and A body shape index [ABSI]) collected at four follow-up periods (from childhood to adult). For cross-sectional analyses, linear regression models were employed to assess factors associated with anthropometric measures. For longitudinal analyses linear mixed models were employed to assess differences in anthropometric measures among SGA versus non-SGA individuals while adjusting for repeated measures.

Results

The analytic baseline cohort were those who participated in Wave 2 (n = 570). In cross-sectional analyses, across all waves those born SGA had smaller anthropometric z-scores compared to non-SGA individuals (β ranging from -0.50 to -0.25). Participants residing in urban environments were significantly larger in Waves 2 to 4 (β ranged 0.26 to 0.65). Those born SGA had higher ABSI scores in Waves 2 and 4 (β 0.26 and 0.37, respectively). In longitudinal analyses, those born SGA had smaller measures of body composition across the life course; these differences were larger in urban communities. In remote communities those born SGA had significantly higher ABSI scores during adolescence and young adulthood, and this difference was not observed in urban communities.

Conclusion

Indigenous Australians born SGA are smaller anthropometrically later in life compared to their non-SGA counterparts. In remote communities, those born SGA had higher levels of central adiposity compared to non-SGA.

Association between perinatal and early life exposures and lung function in Australian Indigenous young adults: The Aboriginal Birth Cohort study

BACKGROUND AND OBJECTIVE

Despite the high burden of respiratory disease amongst Indigenous populations, prevalence data on spirometric deficits and its determinants are limited. We estimated the prevalence of abnormal spirometry in young Indigenous adults and determined its relationship with perinatal and early life factors.

METHODS

We used prospectively collected data from the Australian Aboriginal Birth Cohort, a birth cohort of 686 Indigenous Australian singletons. We calculated the proportion with abnormal spirometry (z-score <-1.64) and FEV1 below the population mean (FEV1 % predicted 0 to -2SD) measured in young adulthood. We evaluated the association between perinatal and early life exposures with spirometry indices using linear regression.

RESULTS

Fifty-nine people (39.9%, 95%CI 31.9, 48.2) had abnormal spirometry; 72 (49.3%, 95%CI 40.9, 57.7) had a FEV1 below the population mean. Pre-school hospitalisations for respiratory infections, younger maternal age, being overweight in early childhood and being born remotely were associated with reduced FEV1 and FVC (absolute, %predicted and z-score). The association between maternal age and FEV1 and FVC were stronger in women, as was hospitalization for respiratory infections before age 5. Being born remotely had a stronger association with reduced FEV1 and FVC in men. Participants born in a remote community were over 6 times more likely to have a FEV1 below the population mean (odds ratio [OR] 6.30, 95%CI 1.93, 20.59).

CONCLUSION

Young Indigenous adults have a high prevalence of impaired lung function associated with several perinatal and early life factors, some of which are modifiable with feasible interventions.

Aldosterone and renin concentrations and blood pressure in young Indigenous and non-Indigenous adults in the Northern Territory: a cross-sectional study

OBJECTIVES

To evaluate aldosterone and renin levels and aldosterone-to-renin ratios (ARRs) in young Indigenous and non-Indigenous adults in the Northern Territory, and their association with blood pressure levels.

DESIGN

Cross-sectional study; single time point sub-study of two prospective birth cohort studies.

SETTING, PARTICIPANTS

Participants in the Aboriginal Birth Cohort (ABC) - born to Indigenous mothers at the Royal Darwin Hospital during 1987-1990 - and the Top End Cohort (TEC) - people born to non-Indigenous mothers in Darwin, recruited during 2007-2009 - aged 32-35 years at the time of this sub-study.

MAIN OUTCOME MEASURES

Plasma aldosterone and direct renin concentrations; ARRs (positive screening test result for primary aldosteronism defined as > 70 pmol/mU); systolic and diastolic blood pressure.

RESULTS

A total of 255 ABC (205 in remote, 50 in urban locations) and 76 TEC members participated. Median aldosterone concentration was similar for all three groups. The median renin concentration was 7.5 mU/L (interquartile range [IQR], 4.1-12.4 mU/L) in the TEC group, 12.4 mU/L (IQR, 5.1-19 mU/L) in the urban ABC group, and 29.3 mU/L (IQR, 15.0-52.9 mU/L) in the remote ABC group. The median ARR was 10 pmol/mU (IQR, 6-19 pmol/mU) in the remote ABC group, 28 pmol/mU (IQR, 16-70 pmol/mU) in the urban ABC group, and 43 pmol/mU (IQR, 26-74 pmol/mU) in the TEC group. Thirteen urban ABC participants (26%), 21 TEC participants (28%), and six people in the remote ABC group (3%) had ARR values above 70 pmol/mU. Adjusted for age and body mass index (BMI), mean systolic and diastolic blood pressure were lower for women than men in all participant groups; after adjusting for age, sex, and BMI, larger ARR was associated with higher systolic blood pressure in the TEC group but not the two ABC groups.

CONCLUSION

Screening test results for primary aldosteronism were positive for about one-quarter of urban Indigenous and non-Indigenous participants. A prospective study that includes confirmatory testing would more accurately assess the prevalence of primary aldosteronism among Indigenous Australians in the Northern Territory.

Birth weight for gestational age and later cardiovascular health: a comparison between longitudinal Finnish and indigenous Australian cohorts

INTRODUCTION

Small or large birth weight for gestational age has been linked with later cardiovascular disease risk. However, cardiovascular risk markers from childhood to adulthood according to birth weight in diverse longitudinal settings globally have not been extensively studied.

OBJECTIVES

To examine the relationship between birth weight and cardiovascular risk profile from childhood until young adulthood in two geographically and socioeconomically distinct cohorts.

METHODS

Data were derived from two longitudinal birth cohort studies; one from southern Finland (Special Turku Coronary Risk Factor Intervention Project, STRIP) and one from northern Australia comprising Indigenous Australians (Aboriginal Birth Cohort, ABC). The sample included 747 Finnish participants and 541 Indigenous Australians with data on birth weight, gestational age and cardiovascular risk factors (body mass index [BMI]), waist-to-height ratio [WHtR], lipid profile, blood pressure) collected at ages 11, 18 and 25 or 26 years. Carotid intima-media thickness (cIMT) was assessed at age 18 or 19 years. Participants were categorised according to birth weight for gestational age (small [SGA], appropriate [AGA] or large [LGA]). Associations between birth weight category and cardiovascular risk markers were studied using a repeated measures ANOVA.

RESULTS

Higher birth weight category was associated with higher BMI later in life in both cohorts (p=.003 for STRIP and p<.0001 for ABC). In the ABC, higher birth weight category was also associated with higher WHtR (p=.004). In the ABC, SGA participants had lower systolic and diastolic blood pressure than AGA participants (p=.028 for systolic, p=.027 for diastolic) and lower systolic blood pressure than LGA participants (p=.046) at age 25. In the STRIP cohort, SGA participants had lower cIMT than LGA participants (p=.024).

CONCLUSIONS

Birth weight can predict future cardiovascular risk profile in diverse populations. Thus, it needs to be included in targeted public health interventions for tackling the obesity pandemic and improving cardiovascular health worldwide.Key messagesThe strongest association between birth weight and later cardiovascular risk profile was manifested as differences in body mass index in two culturally and geographically distinct cohorts.Foetal growth is a determinant for later cardiovascular health in diverse populations, indicating a need to focus on maternal and foetal health to improve cardiovascular health worldwide.

Fingernail cortisol as a marker of chronic stress exposure in Indigenous and non-Indigenous young adults

Cumulative exposure to stress over a long period can negatively impact an individual's health. Significant advancements in biomarkers of chronic stress have been made, with the use of fingernails recently explored. Cross sectional data from the Australian Aboriginal Birth Cohort (Indigenous) and Top End Cohort (non-Indigenous) were used to investigate the associations (sociodemographic and emotional) of fingernail cortisol in Indigenous and non-Indigenous young adults. Details on sociodemographic (age, gender, and Indigenous identification), smoking and alcohol use, emotional wellbeing, and emotional stress (perceived stress and stressful events), and fingernail samples were obtained face-to-face. Fingernail samples were analyzed for 179 Indigenous and 66 non-Indigenous participants (21-28 years). Indigenous participants were subjected to higher rates of stressful events compared to non-Indigenous (Median 6.0; interquartile range (IQR) 4, 9 vs. 1.0; IQR 0, 2; p < .001). Median cortisol levels were similar between Indigenous and non-Indigenous participants (4.36 pg/mg; IQR 2.2, 10.0 vs. 3.87 pg/mg: IQR 2.0, 9.7; p = .68). However, Indigenous participants had a higher cortisol level on adjustment for emotional distress and exposure to stressful events (Geometric Mean 1.82; 95CI: 1.07-3.09), with a negative association with increasing number of stressful events (Geometric Mean 0.94; 95CI 0.90, 0.99). Collection of fingernails was an easily conducted, well-tolerated method to measure stress markers in this multicultural cohort. Indigenous young adults experienced a high number of stressful events which was associated with a lowering of fingernail cortisol levels.Lay abstractChronic stress can impact negatively on health and emotional wellbeing. A fingernail sample provided a culturally acceptable, noninvasive method of measuring chronic stress in Indigenous and non-Indigenous young adults. Cortisol levels, a marker of chronic stress, were different between Indigenous and non-Indigenous young adults and were influenced by emotional status and occurrence of multiple stressful events.

Computerised emotional well-being and substance use questionnaires in young Indigenous and non-Indigenous Australian adults

Background:

Mental health disorders rank among the most substantial causes of morbidity and mortality worldwide. Almost half of Australian adults experience mental illness at some point in their lifetime, with Indigenous Australians disproportionally affected. Thus, it is imperative that effective, acceptable screening tools are used, which are tailored to the target population.

Objectives:

This research investigates the methodology of computerised questionnaires in assessing the emotional well-being and substance use in Indigenous and non-Indigenous young adults.

Methods:

Cross-sectional data from young adults (21–28 years) in the Life Course Program, Northern Territory, Australia, are presented. Through an extensive consultation process, validated questionnaires were adapted to a computerised format suitable for both remote and urban residing Indigenous and non-Indigenous adults.

Results:

Of the 576 participants (459 Indigenous, 117 non-Indigenous) available for assessment, high consent rates were seen, with completion rates >86%. One in three young adults in this cohort were highlighted as ‘at risk’ of psychological distress, and one in five as ‘at risk’ of suicidal ideation or self-harm.

Conclusion:

The target population of this study were at a critical age with high levels of psychological distress and suicidal ideation reported, particularly in Indigenous young adults. This simple, user-friendly, pictorial programme allowed assessment of a sensitive topic anonymously, while simultaneously collating data and identifying those at high risk, irrespective of literacy level or cultural background.

Renal dysfunction is already evident within the first month of life in Australian Indigenous infants born preterm

Antecedents of the high rates of chronic kidney disease in Australian Indigenous peoples may originate early in life. Fourteen percent of Australian Indigenous infants are born preterm (under 37 weeks gestation) and, therefore, at risk. Here, our observational cohort study sought to determine the impact of preterm birth on renal function in Australian Indigenous and non-Indigenous infants. Renal function was assessed between 4-29 days postnatally in 60 Indigenous and 42 non-Indigenous infants born at 24-36 weeks gestation. Indigenous ethnicity was associated with impaired renal function, with significantly higher serum creatinine (geometric mean ratio (GMR) 1.15 [1.06, 1.25]), fractional excretion of sodium (GMR 1.21 [1.04, 1.39]), and urine albumin (GMR 1.57 [1.05, 2.34]), β-2 microglobulin (GMR 1.82 [1.11, 2.98]) and cystatin C (GMR 3.27 [1.54, 6.95]) when controlling for gestational/postnatal age, sex and birth weight Z-score. Renal injury, as indicated by high urine neutrophil gelatinase-associated lipocalin levels, was associated with maternal smoking and postnatal antibiotic exposure. Indigenous infants appeared to be most susceptible to the adverse impact of antibiotics. These findings show that preterm Australian Indigenous infants are highly vulnerable to renal dysfunction. Preterm birth may contribute to their increased risk of chronic kidney disease. Thus, we recommended that renal function should be closely monitored life-long in Indigenous children born preterm.

The Australian Aboriginal Birth Cohort study: socio-economic status at birth and cardiovascular risk factors to 25 years of age

OBJECTIVES

To determine whether socio-economic status at birth is associated with differences in risk factors for cardiovascular disease - body mass index (BMI), blood pressure, blood lipid levels - during the first 25 years of life.

DESIGN

Analysis of prospectively collected data.

SETTING, PARTICIPANTS

570 of 686 children born to Aboriginal mothers at the Royal Darwin Hospital during 1987-1990 and recruited for the Aboriginal Birth Cohort Study in the Northern Territory. Participants resided in 46 urban and remote communities across the NT. The analysed data were collected at three follow-ups: Wave 2 in 1998-2001 (570 participants; mean age, 11 years), Wave 3 in 2006-2008 (442 participants; mean age, 18 years), and Wave 4 in 2014-2016 (423 participants; mean age, 25 years).

MAIN OUTCOME MEASURES

Cardiovascular disease risk factors by study wave and three socio-economic measures at the time of birth: area-level Indigenous Relative Socioeconomic Outcomes (IRSEO) index score and location (urban, remote) of residence, and parity of mother.

RESULTS

Area-level IRSEO of residence at birth influenced BMI (P < 0.001), systolic blood pressure (P = 0.024), LDL-cholesterol (P = 0.010), and HDL-cholesterol levels (P < 0.001). Remoteness of residence at birth influenced BMI (P < 0.001), HDL-cholesterol (P < 0.001), and triglyceride levels (P = 0.043). Mother's parity at birth influenced BMI (P = 0.039).

CONCLUSIONS

Our longitudinal life course analyses indicate that area-level socio-economic factors at birth influence the prevalence of major cardiovascular disease risk factors among Indigenous Australians during childhood and early adulthood.

Hair cortisol and cortisone as markers of stress in Indigenous and non-Indigenous young adults

Chronic, ongoing stress can impact negatively on health and wellbeing. Indigenous Australians are at an increased risk of experiencing multiple stressors. Hair glucocorticoids have been used as a marker for chronic stress. This study aimed to assess the associations of hair cortisol and cortisone with sociodemographic (age, gender, Indigenous Identification), substance use, emotional wellbeing, and emotional stress, in a cohort at increased risk of stressful events and psychological distress. Cross-sectional data (age 21-28 years) are presented from two Australian longitudinal studies; the Aboriginal Birth Cohort (n = 253) and non-Indigenous Top End Cohort (n = 72). A third of the cohort reported psychological distress, with Indigenous participants reporting higher rates of stressful events compared to non-Indigenous (6 vs. 1; p < .001). Significantly higher levels of cortisone were seen in Indigenous women compared to non-Indigenous women (β 0.21; p = .003). A positive association with age was present in hair cortisol and cortisone in Indigenous young adults (β 0.29 and β 0.41; p < .001, respectively). No association with substance use, emotional wellbeing or emotional stress was seen. Sub-analysis in women suggested a possible curvilinear relationship between hair cortisone and the number of stressful events. In this culturally diverse cohort, hair sampling provides a noninvasive, easily conducted and generally well tolerated mechanism to measure stress markers. The association with age, even in this narrow age range, likely represents the manifold changes in circumstances (financial independence, becoming parents, increased risk of substance use and mental illness) that occur during this transitional period of life, particularly for young Indigenous women. LAY ABSTRACT Chronic stress can impact negatively on health and emotional wellbeing. A hair sample is an easy way to measure chronic stress in Indigenous and non-Indigenous young people. The markers of chronic stress, cortisol and cortisone, were different between Indigenous and non-Indigenous, men and women and increased with age in Indigenous young adults.

Iodine status of Indigenous and non-Indigenous young adults in the Top End, before and after mandatory fortification

OBJECTIVE

To assess the median urine iodine concentration (UIC) of young adults in the Top End of Northern Territory, before and after fortification of bread with iodised salt became mandatory.

DESIGN, SETTING

Analysis of cross-sectional data from two longitudinal studies, the Aboriginal Birth Cohort and the non-Indigenous Top End Cohort, pre- (Indigenous participants: 2006-2007; non-Indigenous participants: 2007-2009) and post-fortification (2013-15).

PARTICIPANTS

Indigenous and non-Indigenous Australian young adults (mean age: pre-fortification, 17.9 years (standard deviation [SD], 1.20 years); post-fortification, 24.9 years (SD, 1.34 years).

MAIN OUTCOME MEASURE

Median UIC (spot urine samples analysed by a reference laboratory), by Indigenous status, remoteness of residence, and sex.

RESULTS

Among the 368 participants assessed both pre- and post-fortification, the median UIC increased from 58 μg/L (interquartile range [IQR], 35-83 μg/L) pre-fortification to 101 μg/L (IQR, 66-163 μg/L) post-fortification (P < 0.001). Urban Indigenous (median IUC, 127 μg/L; IQR, 94-203 μg/L) and non-Indigenous adults (117 μg/L; IQR, 65-160 μg/L) were both iodine-replete post-fortification. The median UIC of remote Indigenous residents increased from 53 μg/L (IQR, 28-75 μg/L) to 94 μg/L (IQR, 63-152 μg/L; p < 0.001); that is, still mildly iodine-deficient. The pre-fortification median UIC for 22 pregnant women was 48 μg/L (IQR, 36-67 μg/L), the post-fortification median UIC for 24 pregnant women 93 μg/L (IQR, 62-171 μg/L); both values were considerably lower than the recommended minimum of 150 μg/L for pregnant women.

CONCLUSIONS

The median UIC of young NT adults increased following mandatory fortification of bread with iodised salt. The median UIC of pregnant Indigenous women in remote locations, however, remains low, and targeted interventions are needed to ensure healthy fetal development.

Indigenous Australian household structure: a simple data collection tool and implications for close contact transmission of communicable diseases

Households are an important location for the transmission of communicable diseases. Social contact between household members is typically more frequent, of greater intensity, and is more likely to involve people of different age groups than contact occurring in the general community. Understanding household structure in different populations is therefore fundamental to explaining patterns of disease transmission in these populations. Indigenous populations in Australia tend to live in larger households than non-Indigenous populations, but limited data are available on the structure of these households, and how they differ between remote and urban communities. We have developed a novel approach to the collection of household structure data, suitable for use in a variety of contexts, which provides a detailed view of age, gender, and room occupancy patterns in remote and urban Australian Indigenous households. Here we report analysis of data collected using this tool, which quantifies the extent of crowding in Indigenous households, particularly in remote areas. We use these data to generate matrices of age-specific contact rates, as used by mathematical models of infectious disease transmission. To demonstrate the impact of household structure, we use a mathematical model to simulate an influenza-like illness in different populations. Our simulations suggest that outbreaks in remote populations are likely to spread more rapidly and to a greater extent than outbreaks in non-Indigenous populations.

Examining the Effects of Ambient Temperature on Pre-Term Birth in Central Australia

Preterm birth (born before 37 completed weeks of gestation) is one of the leading causes of death among children under 5 years of age. Several recent studies have examined the association between extreme temperature and preterm births, but there have been almost no such studies in arid Australia. In this paper, we explore the potential association between exposures to extreme temperatures during the last 3 weeks of pregnancy in a Central Australian town. An immediate effect of temperature exposure is observed with an increased relative risk of 1%-2% when the maximum temperature exceeded the 90th percentile of the summer season maximum temperature data. Delayed effects are also observed closer to 3 weeks before delivery when the relative risks tend to increase exponentially. Immediate risks to preterm birth are also observed for cold temperature exposures (0 to -6 °C), with an increased relative risk of up to 10%. In the future, Central Australia will face more hot days and less cold days due to climate change and hence the risks posed by extreme heat is of particular relevance to the community and health practitioners.

Childhood metabolic syndrome, inflammation and carotid intima-media thickness. The Aboriginal Birth Cohort Study

BACKGROUND/OBJECTIVES

We evaluated whether atherosclerotic changes associated with MetS in Australian Aboriginals are reversible in childhood. In addition, we investigated whether heightened inflammation is mediating the adverse effects of MetS.

METHODS

The study cohort comprised of 351 children from the Aboriginal Birth Cohort Study (a longitudinal study based in the Northern Territory of Australia) aged 9-13 years at baseline examination who were followed up 6 years later. MetS was defined by at least three of the following parameters within the extreme sex- and age-specific quartile: highest quartile for waist circumference, blood pressure, triglycerides, and glucose, and lowest quartile for HDL-cholesterol. Carotid intima-media thickness (IMT) and C-reactive protein (CRP) were assessed at follow-up.

RESULTS

Individuals with MetS at baseline or follow-up had increased carotid IMT at follow-up (mean ± SEM 539 ± 3 vs. 561 ± 8 μm, P=0.007; and 537 ± 3 vs. 567 ± 8 μm, P<0.0001 respectively). In combined analyses from baseline and follow-up studies, those individuals with MetS only at baseline had partially improved vascular status; their IMT was not significantly increased compared to those without MetS at both time-points (534 ± 3 vs. 550 ± 10 μm, P=0.09). At the follow-up examination, MetS status was associated with increased IMT levels only among individuals with CRP levels above the median (≥ 2.1mg/l) (536 ± 5 vs. 573 ± 9 μm, P<0.0001, P for interaction 0.01).

CONCLUSIONS

MetS in childhood is associated with subclinical atherosclerosis in an Australian Aboriginal population and the effects appear to be mediated by increased inflammation. The extent of atherosclerosis was partially reduced if metabolic status improved during the follow-up.

Challenges and strategies for cohort retention and data collection in an indigenous population: Australian Aboriginal Birth Cohort

BACKGROUND

Longitudinal prospective birth cohort studies are pivotal to identifying fundamental causes and determinants of disease and health over the life course. There is limited information about the challenges, retention, and collection strategies in the study of Indigenous populations. The aim is to describe the follow-up rates of an Australian Aboriginal Birth Cohort study and how they were achieved.

METHODS

Participants were 686 babies enrolled between January 1987 and March 1990, born to a mother recorded in the Delivery Suite Register of the Royal Darwin Hospital (RDH) as a self-identified Aboriginal. The majority of the participants (70%) resided in Northern Territory within rural, remote and very remote Aboriginal communities that maintain traditional connections to their land and culture. The Aboriginal communities are within a sparsely populated (0.2 people/ km2) area of approximately 900,000 km² (347 sq miles), with poor communication and transport infrastructures. Follow-ups collecting biomedical and lifestyle data directly from participants in over 40 locations were conducted at 11.4 years (Wave-2) and 18.2 years (Wave-3), with Wave-4 follow-up currently underway.

RESULTS

Follow-ups at 11 and 18 years of age successfully examined 86% and 72% of living participants respectively. Strategies addressing logistic, cultural and ethical challenges are documented.

CONCLUSIONS

Satisfactory follow-up rates of a prospective longitudinal Indigenous birth cohort with traditional characteristics are possible while maintaining scientific rigor in a challenging setting. Approaches included flexibility, respect, and transparent communication along with the adoption of culturally sensitive behaviours. This work should inform and assist researchers undertaking or planning similar studies in Indigenous and developing populations.

Lipoprotein(a) identifies cardiovascular risk in childhood: the Australian Aboriginal Birth Cohort Study

AIM

To describe the lipoprotein(a) (Lp(a))profile and its relationship to cardiovascular risk factors in Australian Aboriginal children.

METHODS

A cross-sectional study within a longitudinal birth cohort study in the Darwin Health Region (Northern Territory, Australia). Subjects were Aboriginal children born between 1987 and 1990 who were re-examined between 1998 and 2001. Outcome measures were cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apoB, apoA1, apoA1/B ratio, anthropometric measures, cardiovascular disease (CVD) risk factors, maternal smoking and nutrition.

RESULTS

At a mean age of 11.4 years, results showed that high concentrations of Lp(a) were significantly related to well-known lipid-based CVD risk factors for both boys and girls, and that only one anthropometric factor, height, was significant for girls. Non-genetic factors and maternal smoking were not found to be significant contributors to Lp(a) concentrations.

CONCLUSIONS

Lp(a) should be considered as a more effective marker of CVD than anthropometric measures, and children from families with a history of premature CVD should be regularly screened for this factor.

Glomerulonephritis and managing the risks of chronic renal disease

The rising global burden of chronic renal disease, the high cost of providing renal replacement therapies, and renal disease also being a risk factor for cardiovascular disease is increasing focus on renal disease prevention. This article focuses on the aspects of renal disease (specifically poststreptococcal glomerulonephritis [PSGN] and chronic kidney disease [CKD]) in Indigenous populations in Australia, New Zealand, Canada, and the United States that diverge from those typically seen in the general population of those countries. The spectrum of renal and many other diseases seen in Indigenous people in developed countries is similar to that seen in developing countries. Diseases like PSGN that have largely disappeared in developed countries still occur frequently in Indigenous people. CKD during the childhood years is due to congenital anomalies of the kidney and urinary tract in up to 70% of cases and occurs later in polycystic kidney disease and childhood-onset diabetes. Several risk factors for CKD in adulthood are already present in childhood.

Apo-B/AI ratio identifies cardiovascular risk in childhood: the Australian Aboriginal Birth Cohort study

We describe the lipoprotein and apolipoprotein profiles and their relationship to cardiovascular risk factors in Australian Aboriginal children. This cross-sectional study within a longitudinal birth cohort study involved Australian Aboriginal children born between 1987 and 1990 and re-examined between 1998 and 2001. Height, weight, blood pressure, waist circumference, body fat percentage, cholesterol, triglycerides, HDL-c, LDL-c, apolipoprotein B and A1 were measured. Mean age was 11.4 years (52% male). Mean cholesterol, triglyceride, HDL-c and LDL-c did not differ from reference data. Measures of obesity, blood pressure and prevalence of the metabolic syndrome did not differ in those children with lipoproteins in the upper quartile of the cohort (lower quartile for HDL-c). Boys with an Apo-B/A1 ratio in the upper quartile of the cohort had higher BMI z-score, waist z-score, % body fat, diastolic blood pressure and frequency of the metabolic syndrome (p<0.05). In girls, waist circumference, % body fat and the prevalence of the metabolic syndrome was higher in those with an Apo-B/A1 ratio in the upper quartile (p<0.05).The Apo-B/A1 ratio may be useful to identify cardiovascular risk in Australian Aboriginal children and is suited to clinical practice as the assays are standardised, accurate, automated and a fasting sample is not required.

Large waist but low body mass index: the metabolic syndrome in Australian Aboriginal children

OBJECTIVE

To describe the prevalence and clinical characteristics of the metabolic syndrome (MetS) in a cohort of Australian Aboriginal children.

STUDY DESIGN

Body mass index (BMI), waist circumference, skin fold thickness, body fat percentage, insulin resistance, and the prevalence of MetS were evaluated in 486 children age 9 to 14 years from the Darwin Health Region, Northern Territory, Australia.

RESULTS

Using an age- and sex- specific definition, 14% of the children in the cohort had MetS, 6.4% were overweight, 4.9% were obese, and 26.2% had an elevated waist circumference. The mean percentage of body fat was 30.2%. The children with MetS had higher BMI and waist z-scores, percent body fat, Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) score, and skin fold thickness compared with those without MetS (P < .001); however, >50% of those with MetS were neither overweight nor obese. Waist circumference was significantly associated with insulin resistance as measured by the HOMA-IR (P < .001).

CONCLUSIONS

MetS is common in our cohort despite low rates of overweight and obesity. A tendency for central adiposity is already evident in these young children. Measurement of waist circumference may help identify Aboriginal children at high risk for MetS.

Occurrence and pattern of long bone fractures in growing dogs with normal and osteopenic bones

A retrospective study was undertaken to record the occurrence and pattern of long bone fractures, and the efficacy of Intramedullary (IM) Steinmann pin fixing in growing dogs. All the records of growing dogs during a 10-year-period were screened to record the cause of trauma, the age and sex of the animal, the bone involved, the type and location of the fracture, the status of fixation, alignment, maintenance of fixation and fracture healing. The results were analysed and comparisons were made between growing dogs with normal and osteopenic bones. Among the 310 cases of fractures recorded, the bones were osteopenic in 91 cases (29%). Minor trauma was the principal cause of fracture in dogs with osteopenia (25%), and indigenous breeds were most commonly affected (38%). Fractures in dogs with osteopenic bones were most commonly recorded in the age group of 2-4 months (53%), whereas fractures in normal dogs were almost equally distributed between 2 and 8 months of age. Male dogs were affected significantly more often in both groups. In osteopenic bones, most fractures were recorded in the femur (56%), and they were distributed equally along the length of the bone. Whereas in normal bones, fractures were almost equally distributed in radius/ulna, femur and tibia, and were more often recorded at the middle and distal third of long bones. Oblique fractures were most common in both groups; however, comminuted fractures were more frequent in normal bones, whereas incomplete fractures were more common in osteopenic bones. Ninety-nine fracture cases treated with IM pinning (66 normal, 33 osteopenic) were evaluated for the status of fracture reduction and healing. In a majority of the cases (61%) with osteopenic bones, the diameter of the pin was relatively smaller than the diameter of the medullary cavity (<70-75%), whereas in 68% of the cases in normal bones the pin diameter was optimum. The status of fracture fixing was satisfactory to good in significantly more osteonormal (59%) than osteopenic dogs (42%). Fracture healing, however, was satisfactory in significantly more cases with osteopenic than normal bones. The appearance of callus was relatively early and the amount of bridging callus was relatively large in greater number of osteopenic bone fractures. Mal-union and non-union were recorded more often in osteopenic cases than in normal cases. However, the incidence of bone shortening and osteomyelitis was significantly higher in normal bones than in osteopenic bones.

Management of fractures near the carpal joint of two calves by transarticular fixation with a circular external fixator

A four-ring circular external skeletal fixation device was evaluated for transcarpal fixation of compound fractures in two calves. Case 1 was an eight-month-old female Holstein-Friesian x indigenous breed calf weighing 72 kg, which had a Salter-Harris type II fracture at the distal metaphysis of the right radius/ulna with an open contaminated wound on the medial aspect of the carpus. Case 2 was an 18-month-old crossbred Haryana heifer weighing 105 kg, which had a comminuted fracture at the proximal end of its left metacarpus with severe soft tissue trauma and an open wound on the medial aspect. In both cases, the fractures were repaired with four-ring circular fixators by fixing the proximal two rings in the distal radius/ulna and the distal two rings in the metacarpus. Postoperatively, both calves were treated with analgesic and anti-inflammatory drugs and antibiotic, and the pin-bone interfaces and the open wound were cleaned regularly with povidone-iodine solution. In both animals weight bearing was good to excellent in the immediate postoperative period. The fixator was well maintained and tolerated by the animals until the fractures healed after 45 to 60 days. The movement of the carpal joint was slightly affected when the fixator was removed on day 60, but a follow-up examination after one year showed that both calves had normal functional usage of the limbs.

Comparison of two doses of ropivacaine for lumbosacral epidural analgesia in buffalo calves (Bubalus bubalis )

Six male buffalo calves aged from six to eight months and weighing 100 to 120 kg were used to evaluate the efficacy and safety of caudal epidural analgesia produced by doses of 37.5 mg (5 ml) and 75 mg (10 ml) ropivacaine (0.75 per cent). The study was completed in two phases. In phase 1, all the animals were used twice to evaluate the analgesic and clinical effects of two doses of ropivacaine. In phase 2, the animals were divided into two groups of three to evaluate the effects of two doses of ropivacaine on some haemodynamic and acid-base parameters. Signs of analgesia, as evidenced by a loss of response to pinprick stimulation, were recorded only at the tail, perineum and hindlimbs of the animals given 5 ml ropivacaine, but they extended from the tail to the thorax (T9) in the animals given 10 ml ropivacaine. The duration of analgesia was five to six hours in the animals given 5 ml ropivacaine and seven to eight hours in the animals given 10 ml ropivacaine. Animals of both groups became recumbent, but the score for ataxia was higher in the animals given 10 ml ropivacaine. The respiratory rate decreased significantly (P<0.05) below the baseline in the animals given 10 ml ropivacaine, but the rectal temperature, heart rate, mean arterial pressure, central venous pressure and acid-base and electrolyte parameters did not change significantly in either group.

Articular Cartilage Repair with Autografting Under the Influence of Insulin-Like Growth Factor-1 in Rabbits

Insulin-like growth factor (IGF)-1 has been successfully demonstrated to stimulate proteoglycan synthesis, slow down its catabolism and promote cartilage formation through well defined in vitro studies. It was therefore, assumed that IGF-1 would eventually serve to augment current cartilage repair techniques in vivo. Study was therefore, designed to determine the influence of IGF-1 in cartilage repair with or without autografting. For this purpose articular cartilage repair model was created in the left knee of 48 New Zealand white rabbits of either sex, 6-7 months old, weighing 1-2 kg. The articular cartilage defect was created in the femoral groove of femoro-patellar joint using hand held trephine under xylazine and ketamine anaesthesia in all the animals. The defect created was 3 mm in diameter and 2 mm in depth. For autografting, osteochondral tissues harvested from the proximal patellar groove of the femur were placed in the distal defect and vice versa. The experimental animals were divided mainly into four groups, i.e. Group A (control), Group B (autografting), Group C (control + IGF-1) and Group D (autografting + IGF-1). Animals of group A and B were provided only with collagen scaffolds at 10 mug/cm(2) whereas animals of treatment group C and D were provided with collagen scaffolds holding 30 ng/30 mul of IGF-1 into the defect. Evaluation of cartilage repair was done on days 15, 30 and 45 after ethically killing the animals. Initially IGF-1 had shown the tendency for either in the maintenance of autografted cartilage or helped in proliferation of chondroblast for the repair process. However, later in the process, cartilage formation apparently declined and appeared to converge to osseous tissue. Collectively, non-responsiveness of osteoarthritic chondrocytes to IGF-1 could be partially attributed to either increased IGF-binding proteins in the joint space, micromovement of the graft, lack of nutrition, dose of IGF-1 or its half life in the current study.

Clinicophysiological Effects of Spinally Administered Ketamine and Its Combination with Xylazine and Medetomidine in Healthy Goats

The study was conducted in 9 healthy adult goats of either sex, weighing 15-20 kg, to evaluate and compare the clinicophysiological effects of spinally administered ketamine alone and in combination with xylazine and medetomidine. Nine trials each of the three treatments were conducted randomly by injecting ketamine (2.5 mg/kg) (n = 9), ketamine and xylazine (2.5 mg/kg and 0.05 mg/kg) (n = 9) and ketamine and medetomidine (2.5 mg/kg and 10 microg/kg) (n = 9). The drugs were administered at the lumbosacral subarachnoid space under strict aseptic conditions. The treatments were evaluated on the basis of clinicophysiological, haematological, biochemical and haemodynamic observations. Ketamine produced mild to moderate analgesia of the hindquarters. Its combination with either xylazine or medetomidine produced complete analgesia of the hindquarters for 45-60 min. Ataxia was moderate in the ketamine group, whereas animals attained sternal recumbency in the combination groups. A moderate degree of sedation was recorded in the combination groups. Heart rate and respiratory rate depression in the combination groups and heart rate and respiratory rate stimulation in ketamine group were recorded. Haematological parameters decreased in all the groups. Increase in serum glucose, creatinine and urea nitrogen was recorded in all the groups. Serum electrolytes did not show any significant change. The results showed that the combination of ketamine with xylazine or medetomidine at these dose rates produced a comparable degrees of analgesia of hindquarters with transient and minimal cardiopulmonary side effects.

Effects of epidural ketamine-xylazine combination on the clinicophysiological and haematobiochemical parameters of uraemic and healthy goats

Xylazine-ketamine combination was evaluated for its efficacy and safety after epidural administration in uraemic and healthy goats. The combination (xylazine 0.025 mg/kg and ketamine 2.5 mg/kg) was administered to uraemic (n = 6) and healthy (n = 6) animals in the lumbosacral epidural space. The combination was evaluated in terms of clinical, physiological, haematological and biochemical parameters. The onset of analgesia was faster in healthy animals than in uraemic animals. Xylazine and ketamine produced complete analgesia of tail, perineum, inguinal and thigh regions in all animals of both groups. However, healthy animals showed longer duration of complete analgesia than did uraemic animals. Greater ataxia was recorded in healthy animals than in uraemic animals. The heart rate showed a significant decrease in both groups; however, respiratory rate and rectal temperature did not show any significant changes. Haemoglobin, packed cell volume and total leukocyte count decreased non-significantly in both groups. Total leukocyte count was significantly higher in uraemic animals. A significantly higher value of urea nitrogen and creatinine was recorded in uraemic animals. The blood electrolytes (Na+, K+ and Cl-) and blood gases (PO2 and PCO2) did not show any significant changes in both groups; however, base excess was significantly higher in uraemic animals. The effects produced by the combination on different systems were transient and values normal as the effect of the drugs wore off. The results suggest that the combination when used epidurally in uraemic goats produced effective and safe surgical analgesia.

Xylazine, Ketamine and their Combination for Lumbar Epidural Analgesia in Water Buffalo Calves (Bubalus bubalis)

The study was conducted to evaluate the effects of xylazine individually (0.05 mg/kg), ketamine individually (2.5 mg/kg), and a combination of xylazine and ketamine (0.05 mg/kg and 2.5 mg/kg) after lumbar epidural administration in water buffalo calves. Fifteen non-descript, male water buffalo calves of 6-8 months of age weighing between 55 and 75 kg were randomly placed in three groups (groups A, B and C). The agents were administered at the first lumbar epidural space. Clinico-physiological parameters, such as analgesia, ataxia, sedation, salivation, heart rate, respiratory rate and rectal temperature were studied. Other haematological and biochemical parameters monitored were haemoglobin, packed cell volume, total leukocyte count, plasma glucose, cortisol, protein albumin, globulin, blood urea nitrogen (BUN), creatinine, alanineamino transferase (ALT), sodium, potassium and chloride. The onset of analgesia (mean +/- SEM) was faster in group C (3.2 +/- 0.20 min) compared with that of group B (4.6 +/- 0.22 min) and group A (34.0 +/- 1.86 min). Analgesia of the thorax, flank, inguinal region, hind limbs, perineum and tail was complete in group C, but mild to moderate in groups A and B. Ataxia was severe in group C and mild in groups A and B. Mild to deep sedation was produced by groups A and C animals. Group B animals failed to produce sedation. Longer duration and greater depth of analgesia was produced in animals of group C. Heart rate, respiratory rate and rectal temperature decreased in groups A and C. The haematological parameters decreased in all the groups. The biochemical parameters like glucose, cortisol, BUN, creatinine, and ALT increased in all the animals. However, total proteins and albumin decreased in the three groups. The plasma electrolytes sodium, potassium and chloride did not show any significant change. The results of this study indicated a possible synergistic analgesic interaction between epidurally administered xylazine and ketamine, without causing any marked systemic effects in water buffalo calves.

Reduced nephron number and glomerulomegaly in Australian Aborigines: A group at high risk for renal disease and hypertension

Aborigines in remote areas of Australia have much higher rates of renal disease, as well as hypertension and cardiovascular disease, than non-Aboriginal Australians. We compared kidney findings in Aboriginal and non-Aboriginal people in one remote region. Glomerular number and mean glomerular volume were estimated with the disector/fractionator combination in the right kidney of 19 Aborigines and 24 non-Aboriginal people undergoing forensic autopsy for sudden or unexpected death in the Top End of the Northern Territory. Aborigines had 30% fewer glomeruli than non-Aborigines--202,000 fewer glomeruli per kidney, or an estimated 404,000 fewer per person (P=0.036). Their mean glomerular volume was 27% larger (P=0.016). Glomerular number was significantly correlated with adult height, inferring a relationship with birthweight, which, on average, is much lower in Aboriginal than non-Aboriginal people. Aboriginal people with a history of hypertension had 30% fewer glomeruli than those without--250,000 fewer per kidney (P=0.03), or 500,000 fewer per person, and their mean glomerular volume was about 25% larger. The lower nephron number in Aboriginal people is compatible with their susceptibility to renal failure. The additional nephron deficit associated with hypertension is compatible with other reports. Lower nephron numbers are probably due in part to reduced nephron endowment, which is related to a suboptimal intrauterine environment. Compensatory glomerular hypertrophy in people with fewer nephrons, while minimizing loss of total filtering surface area, might be exacerbating nephron loss. Optimization of fetal growth should ultimately reduce the florid epidemic of renal disease, hypertension, and cardiovascular disease.

Ultrasound Therapy in Tendinous Injury Healing in Goats

The effect of ultrasound therapy on tendon injury healing was studied on 12 locally available non-descript adult goats of either sex divided equally in two groups (I and II) consisting of six animals each. The superficial digital flexor tendon (SDFT) was transected and immediately repaired with nylon (2/0) using a locking loop suture pattern under atropine-triflupromazine-lignocaine epidural analgesia and strict aseptic condition. A full limb plaster of Paris cast was applied to immobilize the operated limb for 3 days. Postoperative care was similar in both the groups. In group I, the operated limb was allowed to heal without ultrasound therapy. In group II, pulsed ultrasound therapy was started 3 days after repair of tendinous injury at an intensity of 1 W/cm(2) for 10 min daily for 10 consecutive days. The animals of both groups were evaluated clinically and haemato-biochemically on days 1, 3, 7, 15, 20 and 30 postoperatively. Air tendonograms and ultrasonography were performed on days 0, 10, 20 and 30 post-tenorrhaphy. Histopathological examination of tendon biopsy samples was performed on day 30 post-tenorrhaphy. Resolution of inflammatory swelling, pain, weight bearing and tendon gliding movement was earlier in the test group than control. Rectal temperature, total leucocyte count and differential leucocyte count did not vary significantly at various stages of observation in both the groups. Serum glucose, cortisone and serum alkaline phosphatase levels increased significantly after tendon injury repair in all the animals and decreased slowly at all subsequent intervals in control group, whereas, it was near normal in the treatment group on day 30 post-tenorrhaphy. Air tendenograms and ultrasonography examinations in the test group revealed that there was a marked regression of peritendinous adhesion between the tendon and skin on day 30 post-tendon injury repaired and the tendon at the reconstructive site attained near normal thickness and density. Adhesions were present in the reconstructed site of SDFT in all animals of the control group. Histopathologically, the granulation tissue was comparatively bettered organized at the healing site in the ultrasound-treated animals.

Effects of xylazine, lignocaine and their combination for lumber epidural analgesia in water buffalo calves (Bubalus bubalis)

The study was conducted to evaluate the effects of xylazine alone (0.05 mg/kg), lignocaine alone (2.0 mg/kg) and a combination of xylazine and lignocaine (0.05 mg/kg and 2.0 mg/kg, respectively) after lumbar epidural administration in water buffalo calves. Fifteen nondescript, male water buffalo calves of 6-8 months of age and weighing between 55 and 75 kg were randomly placed in 3 groups (A, B and C). The agents were administered at the 1st lumbar epidural space. Clinico-physiological parameters such as analgesia, ataxia, sedation, salivation, heart rate, respiratory rate and rectal temperature were studied. Other haematological and biochemical parameters monitored were haemoglobin, packed cell volume, total leukocyte count, plasma glucose, cortisol, protein albumin, globulin, blood urea nitrogen, creatinine, ALT, sodium, potassium and chloride. The onset of analgesia was faster in group C (3.0 +/- 0.44 min) compared with that of group B (4.4 +/- 0.40 min) and group A (34.0 +/- 1.86 min). Analgesia of the thorax, flank, inguinal region, hind limbs, perineum and tail was complete in group C, but mild to moderate in groups A and B. Ataxia was severe in groups B and C and mild in group A. Mild to deep sedation were produced by groups A and C animals. Longer duration and greater depth of analgesia was produced in animals in group C. Heart rate, respiratory rate and rectal temperature decreased in groups A and C. The haematological parameters decreased in all the groups. The biochemical parameters like glucose, cortisol, blood urea nitrogen, creatinine, ALT increased in all the animals. However, total proteins and albumin decreased in the 3 groups. The plasma electrolytes sodium, potassium and chloride did not show any significant change. The results of this study indicated a possible additive analgesic interaction between epidurally administered xylazine and lignocaine, without causing any marked systemic effects in water buffalo calves.

Renal ultrasound findings in an Australian Aboriginal population with high rates of renal disease

BACKGROUND

Rates of albuminuria and haematuria are extremely high with haematuria prevalence as high as 30-50% in adults of some Aboriginal groups. Dipstick testing of urine is routinely carried out in Aboriginal communities and as part of school screening programmes. Evaluation of the many affected individuals has traditionally included renal ultrasound examination, which involves considerable expense and logistic problems in remote communities. The present study was conducted to evaluate the usefulness of ultrasound in this setting.

METHODS

A population survey was conducted in a remote community. Urine dipstick analysis and the albumin:creatinine ratio (ACR; g/mol) were measured in 1440 people over 5 years of age (89% of the eligible population), and a detailed renal ultrasound examination was performed in a random subset of 647 people (41.1% of the whole group), 276 aged 5-19 years and 371 over 20 years of age.

RESULTS

Urine dipstick proteinuria (>1+) was present in 8.5% (23/271) of those aged 5-19 years and 37.9% (132/348) in those aged over 20 years; pathological albuminuria (ACR>3.4) was present in 7.6% (21/276) and 54.7% (203/371), respectively, and isolated haematuria was present in 7.7% (21/273) and 11.5% (40/347), respectively. Eight ultrasound abnormalities were found. Ultrasound findings did not change the management of any individual.

CONCLUSION

Renal ultrasound added little to the evaluation of people with asymptomatic proteinuria or haematuria in this setting. In this scenario, ultrasound examination could be reserved for the cases with an unusual presentation where findings are likely to influence the prognosis or treatment, or in preparation for a renal biopsy.

The use of a circular external skeletal fixation device for the management of long bone osteotomies in large ruminants: an experimental study

The study was undertaken to evaluate the feasibility of a simple, inexpensive model of circular external fixator (CEF) for use in large ruminants. A simple model of CEF frames consisting of four full rings (13-19 cm diameter, 4 cm wide and 4 mm thick with 18-24 holes) connected by threaded rods (8 mm diameter, 10-15 cm long) and nuts was developed using mild (low carbon) steel and were nickel-plated. In the first phase of the study, three male cow calves were utilized to study the feasibility of application of the fixators in the metatarsus, tibia and radius, in reference of adaptation and tolerance by animals. In the second phase, the fixators were tested in osteotomized bones. Six bull calves of 1.5-2 years of age weighing about 200-250 kg were utilized for this purpose. After preparing the area for aseptic surgery, under xylazine (at 0.1 mg/kg, i.m.)-ketamine (i.v. till effect) general anaesthesia, the test bone (metatarsus, radius and tibia in two animals each) was approached through the medial surface and an osteotomy was created with a saw and chisel at the mid-diaphysis. The pre-constructed 4-ring CEF was mounted on the limb around the test bone in such a way that it formed a cylinder with the axis of the limb at the centre. Each ring was then fixed to the bone with a pair of beaded wires (316 SS) of 3.5 mm diameter. During the post-operative period, the animals were observed for any change in behaviour, tolerance of the fixators, the weight bearing on the test limb, the status of the fixator, and the level of reduction of the osteotomy, alignment and healing at different intervals. The fixation of CEF was easier in the metatarsus and radius than in the tibia. The inner ring diameters found adequate for metatarsus, radius and tibia were 13-15 cm, 15-17 cm and 17-19 cm, respectively. The fixators applied to different bones were well-tolerated, and the animals could lay down, stand and walk freely with the fixator without any problems. All the animals showed good weight bearing in the immediate post-operative period. Weight bearing, however, slightly reduced in the inflammatory period and showed improvement after about 4 weeks. Wire tract infection was seen in all the animals, which was more on proximal wire tracts on lateral aspect of limbs. Circular fixators were well-tolerated by all the animals, and there was no breaking/bending of connecting rods, slotted bolts or the rings at any stage of observation. Slight bowing of some wires was noticed in cases of tibia and radius (in phase II) and bending of some wires was noticed from first week in two animals one each in radius and tibia. Bone fragments were well maintained until healing occurred (appearance of bridging periosteal callus) at 60-70 days. The functional results were good in all but one case of tibia, where a mal-union was recorded. From this study, it can be concluded that CEF are well-tolerated by large ruminants and can be used to treat long bone fractures. The fixator assembly using mild steel is sufficiently strong to maintain fracture fixation and is inexpensive. The simple design of the CEF appears to be sufficient to treat simple diaphyseal fractures of the metatarsus and radius. Improvement in the technique of fixation and design-like coupling of linear and circular fixator components into hybrid constructs may help to provide greater rigidity in treating tibial and open long bone fractures.

Kidney volume, blood pressure, and albuminuria: findings in an Australian aboriginal community

BACKGROUND

Australian Aborigines are experiencing epidemic proportions of renal disease, marked by albuminuria and, variably, hematuria. They also have high rates of low birth weight, which have been associated with lower kidney volumes and higher blood pressures. The authors evaluated relationships between kidney volume, blood pressure, albuminuria, and hematuria in 1 homogeneous group.

METHODS

Forty-three percent (672 of 1,560) of the population in a remote coastal Australian Aboriginal community aged 4.4 to 72.1 years participated in the study.

RESULTS

Kidney size correlated closely with body size. Systolic blood pressure (SBP) was correlated inversely with kidney length and kidney volume, after adjusting for age, sex, and body surface area (BSA); a 1-cm increase in mean kidney length was associated with a 2.2-mm Hg decrease in SBP, and a 10-mL increase in mean kidney volume was associated with a 0.6-mm Hg decrease in SBP (P = 0.001). Mean kidney volume explained 10% of the variance in SBP in a multivariate model containing age, sex, and BSA. In addition to higher SBP, adults who had the lowest quartiles of kidney volume also had the highest levels of overt albuminuria (P = 0.044).

CONCLUSION

Smaller kidneys predispose to higher blood pressures and albuminuria in this population. The lower volumes possibly represent kidneys with reduced nephron numbers, which might be related to an adverse intrauterine environment. Susceptibility to renal disease could be a direct consequence of reduced nephron numbers; the higher blood pressures with which they are associated could also contribute to, as well as derive from, this association.

Acellular and Glutaraldehyde-Preserved Tendon Allografts for Reconstruction of Superficial Digital Flexor Tendon in Bovines: Part I - Clinical, Radiological and Angiographical Observations

Sixteen tenorrhaphies were performed at the mid-metatarsal region in eight buffalo calves under lignocaine epidural analgesia. A 2 cm long gap was created in the superficial digital flexor (SDF) tendon and immediately repaired with acellular grafts in animals of group I, 1% glutaraldehyde-preserved tendon allografts in group II. In group III, the defect was repaired with autografts. This group served as control. The contralateral limb in each animal was operated after an interval of 60 days and the animals underwent the same procedure according to the designed groups. Diclofenac sodium and Enrofloxacin was given post-operatively for 5 days. Clinical examination revealed significant increase (P < 0.05) in rectal temperature, heart and respiratory rate for 3-4 postoperative days in all the animals. Mild pain and exudation as well as early restoration of tendon gliding movements and weight-bearing were observed earlier in group I in comparison with group II. Air-tendograms revealed early organization, minimal adhesion formation and lesser thickening of tendon at the reconstructive site in the acellular group whereas in the glutaraldehyde group dense homogenous swelling with adhesions was seen along the flexors. Angiography on day 30 showed that the area of proximal and distal host tendon graft junction appeared hypervascularized, whereas the area occupied by the graft appeared relatively less vascularized. Normal vascularization was observed on day 90 in all the three groups.

The association between birthweight and current blood pressure: a cross‐sectional study in an Australian Aboriginal community

OBJECTIVES

To study the relationship of blood pressure to birthweight and current body mass index in a population with high rates of low birthweight (< 2.5 kg).

DESIGN

A cross-sectional population screening program conducted between 1992 and 1998, with retrospective retrieval of birthweights.

SETTING

A remote coastal Australian Aboriginal community with a high prevalence of diabetes, cardiovascular and renal disease.

PARTICIPANTS

Eighty-two per cent of the community members (1473/1805) were screened. Birthweights were available for 767 (71%) of the screened participants aged 7-43 years.

MAIN OUTCOME MEASURES

The association between birthweight and current blood pressure, accounting for current body mass index.

RESULTS

Mean birthweights were low, and 18% of children and 35% of adults had been low-birthweight babies. In children (7-17 years), blood pressure was not correlated with birthweight, but in adults there was an inverse correlation - a 1 kg increase in birthweight was associated with a 2.9 mmHg (95% CI, 0.3-5.5 mmHg) decrease in systolic blood pressure, after adjusting for age, sex and current weight. Overweight adults with low birthweight had the highest blood pressures.

CONCLUSIONS

Low birthweight is significantly associated with higher blood pressure in adult life, and the effect is amplified by higher current weight. Given the high rates of low birthweight in Aboriginal people in remote areas, and the detrimental effect of higher blood pressures on chronic diseases (currently present in epidemic proportions), interventions should focus on improving birthweights and on weight control in adolescents and adults. Special attention should be paid to children with low birthweight to avoid their becoming overweight in adult life.

Interaction Between Epidurally Administered Ketamine and Pethidine in Dogs

The present study was designed to test the hypothesis that a synergistic interaction could be recorded after epidural administration of ketamine-an N-methyl-D-aspartate (NMDA) antagonist and pethidine--an opioid agonist. Twelve adult mongrel dogs of either sex were randomly divided in three groups A, B and C of four animals each. Ketamine (5%) at 2.5 mg/kg and pethidine (3%) 2 mg/kg were injected at lumbosacral epidural space in animals of groups A and B, respectively. In animals of group C ketamine (2.5 mg/kg) and pethidine (2 mg/kg) were injected. Heart rate increased significantly up to 15 min in group A, whereas in groups B and C, the increase was non-significant for a period of 10 and 45 min, respectively. Respiration increased gradually up to 45-60 min in group A and for 15-20 min in group B. However, in animals of group C respiration fell below the baseline during the first 10-15 min and then returned near the baseline. Rectal temperature decreased only marginally in all the groups. Ketamine alone produced complete analgesia at tail and perineal region for a period of 5-10 min and then moderate analgesia for the next 20-30 min. Analgesia at the flank was moderate to complete between 5 and 15 min. In group B complete analgesia was only moderate at the tail and perineal region up to 30 min. In animals of group C, complete analgesia was observed only at perineal region for a very short period (5 min). Analgesia was not associated with sedation in any of the groups but animals of groups A and C showed signs of motor incoordination. Results of the study suggest rather antagonistic than synergistic interaction between epidurally administered ketamine and pethidine. Further studies are needed to confirm the antagonistic interaction between the two drugs.

Growth and morbidity in children in the Aboriginal Birth Cohort Study: the urban-remote differential

OBJECTIVES

To describe the prevalence of markers of growth, chronic and infectious disease in peripubertal Aboriginal children living in the Darwin Health Region in the "Top End" of the Northern Territory, and to compare prevalence between children living in urban and remote areas.

DESIGN

Cross-sectional survey nested in a prospective birth cohort.

SUBJECTS

482 children living in the region who were recruited at birth (Jan 1987 to Mar 1990) and were followed up between 1998 and 2001, when aged 8-14 years.

MAIN OUTCOME MEASURES

Selected parameters of growth and nutrition, infectious disease and potential markers of chronic adult disease were compared between children living at follow-up in suburban situations in Darwin-Palmerston (urban) and those living in rural communities with an Aboriginal council (remote).

RESULTS

Remote children were shorter than urban children (mean height, 141.7 v 146.3 cm; P < 0.001), lighter (median weight, 30.3 v 37.1 kg; P < 0.001) and had lower body mass index (median, 15.3 v 17.9 kg/m(2); P < 0.001) and haemoglobin level (mean, 125.1 v 130.9 g/L; P < 0.001). Some potential markers of adult chronic disease were higher in urban than remote children: systolic blood pressure (mean, 109.6 v 106.2 mmHg; P = 0.004), and levels of total cholesterol (4.3 v 4.0 mmol/L; P < 0.001), high-density lipoprotein cholesterol (mean, 1.4 v 1.2 mmol/L; P < 0.001) and insulin (median, 7 v 4 mU/L; P = 0.007). Diastolic blood pressure, levels of red cell folate, serum glucose and low-density lipoprotein cholesterol, and urinary albumin-creatinine ratio did not differ by location. The prevalence of visible infections was also higher in remote than urban children (P < 0.05).

CONCLUSION

As some markers of health differ between peripubertal Aboriginal children living in urban areas and those in remote areas, results of surveys in remote areas cannot be generalised to urban Aboriginal populations.

Ultrasonographic evaluation of urinary bladder in normal, fern fed and enzootic bovine haematuria-affected cattle

A total of 19 adult hill cattle of both sexes were subjected to trans-rectal ultrasound scanning of urinary bladder to evaluate bladder wall thickness and the presence of space-occupying lesions. The animals were divided into four groups. Eight apparently healthy hill cattle maintained under standard ration served as control (group I) and the remaining II animals were divided into three groups (II, III and IV). Group II animals (n = 8) were fed with different type of ferns which were further divided into subgroups II-P, -D and -B and fed with Polystichum squarrosom (n = 2). Dryopteris juxtaposita (n = 2) and Pteridium aquilinum (n = 4) ferns, respectively. The one animal in group III was a natural case of enzootic bovine haematuria (EBH) and the two animals in group IV were natural cases of microscopic EBH fed with Polystichum squarrosum fern. In group I animals, the average bladder wall thickness was 1.45 mm. The delineation of the bladder wall was uniformly smooth and the echo pattern of the bladder was homogeneously black, which was suggestive of clear urine content. In group II (P, D and B) the average bladder wall thickness of the six animals was 1.87 mm and the sonographic features were within normal limit when compared with controls. In two of the animals of group II-B, the bladder wall was apparently thick (4.36 mm) and there was no intraluminal mass except at one or two focal elevated points. Animals of groups III and IV showed the average bladder wall thickness of 4.86 mm and were characterized by the presence of irregular sessile masses extending into the bladder lumen. The homogeneous anechoic area was reduced centrally due to the presence of a hypoechoic soft tissue mass all around the bladder wall. Post-sonographic urinalysis, biopsy and necropsy of selected cases further confirmed the sonographic findings.

Carbon fibres and plasma-preserved tendon allografts for gap repair of flexor tendon in bovines: clinical, radiological and angiographical observations

Twenty-four tenorrhaphies were performed at the mid-metatarsal region in 12 crossbred calves under xylazine-ketamine spinal analgesia. A 2.5-cm long gap was created in the superficial digital flexor (SDF) tendon and immediately repaired with carbon fibres in the animals of group I and with plasma-preserved tendon allografts in group II. Clinical examination revealed a slight increase (P > 0.05) in rectal temperature, heart and respiratory rate for 2-4 days postoperation in both groups. Milder pain and exudation as well as earlier restoration of tendon gliding movements and weight bearing were observed in group I as compared to group II. Air-tendogram in the carbon fibre group on day 30 revealed restoration of continuity across the defect of the tendon. whereas, in the allograft group, a dense homogeneous swelling was seen along the flexors. Regression of peritendinous adhesions and swelling at the reconstructed site at later stages was seen in both groups. Angiography showed hypervascularization at the reconstructed site on day 14 in the carbon fibre group, however, in the allograft group the site appeared to be relatively avascular. On days 30 and 90, blood vessels were normally organized in both groups.

Fractures secondary to nutritional bone disease in dogs: a review of 38 cases

The pattern of bone fractures secondary to nutritional bone disease in 38 dogs was analysed using a radiographic survey. The majority of fractures were either caused by a fall (28.95%) or showed no history of direct trauma (31.58%). Mongrels were more commonly affected by pathological fractures, followed by Dobermanns and German Shepherds. Significantly more (P < 0.05) fractures were found in dogs aged less than 6 months (64.71%). The incidence of such fractures was significantly higher in males than in females (M:F = 2.70:1.00). General radiological signs included a generalized decrease in cortical density, thinning of cortices and widening of metaphyses/epiphyses in most of the animals. Fractures were found significantly more frequently (P < 0.01) in the femur (81.58%) than in any other bone. Of the different types of fracture, complete oblique and incomplete fractures were most common.

Effects of subarachnoid xylazine and medetomidine on haemodynamics and ECG in goats

The effects of subarachnoid administration of the alpha 2-agonists xylazine and medetomidine on haemodynamic parameters in six adult goats were evaluated. Xylazine (0.05 mg/kg body wt) or medetomidine (0.01 mg/kg body wt) was administrated in the lumbosacral subarachnoid space. Mean arterial blood pressure and central venous pressure and electrocardiograms were monitored up to 120 min post-injection. Xylazine and medetomidine produced significant and comparable decreases in mean arterial blood pressure in the post-injection period. However, mean central venous pressure increased during this period. The ECG changes produced by these drugs were bradycardia and increased PR and QT intervals. The study suggested that both alpha 2-agonists depress haemodynamic parameters and produce comparable effects after subarachnoid administration.

Bone morphogenetic proteins--novel regulators of bone formation

Bone morphogenetic proteins (BMPs), hydrophobic, non-species specific glycoproteins, belong to the expanding transforming growth factor-beta (TGF-beta) superfamily. BMP has pleiotropic function that range from extraskeletal and skeletal organogenesis to bone generation and regeneration. It induces de novo bone formation in post fetal life through the process of direct (intra membranous) and endochondral ossification and their response is dose dependent. Through recombinant gene technology, BMP is available at least in ten forms for basic research and clinical trials. Amino acid sequences and physical properties of BMP family members have been identified. BMP research extends to the fields of developmental biology, genetics and evolution.

Hyperthyroidism in children: an Indian experience

During the period 1986-1993, 24 children with hyperthyroidism were referred to us for management. Two of them had factitious hyperthyroidism, one toxic nodular goiter and another neonatal Graves' disease. Twenty children (6M, 14F) had Graves' disease. Their age at presentation was 10.86 +/- 2.02 years and duration of symptoms ranged from 2.5 months to 7 years. Neuropsychiatric manifestations, such as hyperkinesis, irritability, excitability and behavioral problems, were the most common initial presenting symptoms (90%). Goiter of varying grades was present in 18 children. Eye involvement of mild or moderate intensity was present in 85% and cardiac involvement in 30%. Serum free thyroxine and triiodothyronine levels were high and radioactive iodine uptake was elevated. All of them received carbimazole 0.5-0.7 mg/kg in three divided doses. Seventeen responded to therapy over a period of time while three did not. On withdrawal, six of the responders relapsed. Hyperthyroidism in children is rare and when it occurs it is almost always due to Graves' disease. The prominence of neuropsychiatric symptoms, insidious onset and absence of severe infiltrative ophthalmopathy differentiates it from the adult type of disease. Prolonged medical therapy is needed to induce good continued remission.