Biomedical subjects
Publications and source records attributed to J D Mathews.
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Ribotyping with the restriction enzyme XbaI was used to study the dynamics of Carriage of non-encapsulated Haemophilus influenzae (NCHi) in Aboriginal infants at risk of otitis media. Carriage rates of NCHi in the infants in the community were very high; the median age for detection was 50 days and colonization was virtually 100% by 120 days of age and persisted at a high level throughout the first year of life [1]. Eighteen different ribotypes of NCHi were identified from 34 positive swabs taken from 3 infants over a period of 9 months. The same ribotypes were recovered for up to 3 months from consecutive swabs of individual infants, and 12 of 27 swabs (44.4%) yielded two ribotypes from four colonies typed. Statistical analysis suggested that most swabs would have been positive for two ribotypes if enough colonies had been typed although the second most frequent ribotype was detected on average in only 13% of strains. Early colonization and carriage of multiple ribotypes of NCHi may help to explain the chronicity of carriage and thus the persistence of otitis media in Aboriginal infants.
1. Australian Aborigines have high rates of both cardiovascular mortality and renal failure and the usual male dominance in these conditions is respectively reduced and effaced. 2. In one Aboriginal community, we have demonstrated a strong association between albuminuria and cardiovascular risk factors and a relationship of both with insulin resistance, which is more pronounced in females than males. 3. We propose that albuminuria is a component of Syndrome X and that reduction in levels of albuminuria should prove to be a useful marker of effectiveness in treatment programmes targeting cardiovascular risk as well as renal disease.
BACKGROUND: Thrombolytic treatment with streptokinase in acute myocardial infarction has proven to be safe and effective in Caucasian populations with relatively low levels of anti-streptokinase IgG and streptokinase resistance. Higher levels of antibodies, as seen in previous recipients of streptokinase therapy, cause more adverse reactions and may result in lower efficacy. AIMS: To examine the levels of anti-streptokinase IgG and streptokinase resistance in a population subjected to endemic streptococcal infections. METHODS AND RESULTS: Thirty Aboriginal adults from a remote community in Northern Australia with endemic streptococcal infections and 15 non-Aboriginal adults from an urban community without endemic infections participated in this study. Aboriginal adults exhibited levels of anti-streptokinase IgG and streptokinase resistance that, respectively, were almost 20 and 15 times greater than the values of non-Aboriginal adults. At least 23% of Aboriginal adults had sufficiently high levels of streptokinase resistance to neutralise a standard 1.5 million unit dose of streptokinase. CONCLUSIONS: Aboriginal adults from a remote community had dramatically elevated levels of anti-streptokinase IgG and in vitro streptokinase resistance. Prospective studies are needed to assess the clinical relevance of streptokinase resistance in populations from areas with endemic streptococcal infection.
OBJECTIVE: To assess the long term effect of a nutrition program in a remote Aboriginal community (Minjilang). DESIGN: Evaluation of nutritional outcomes over the three years before and the three years after a health and nutrition program that ran from June 1989 to June 1990. Turnover of food items at the community store was used as a measure of dietary intake at Minjilang and a comparison community. SETTING: A community of about 150 Aboriginal people live at Minjilang on Croker Island, 240 km north-east of Darwin. A similar community of about 300 people on another island was used as the comparison. RESULTS: The program produced lasting improvements in dietary intake of most target foods (including fruit, vegetables and wholegrain bread) and nutrients (including folate, ascorbic acid and thiamine). Sugar intake fell in both communities before the program, but the additional decrease in sugar consumption during the program at Minjilang "rebounded" in the next year. Dietary improvements in the comparison community were delayed and smaller than at Minjilang. CONCLUSIONS: The success of the program at Minjilang was linked to an ongoing process of social change, which in turn provided a stimulus for dietary improvement in the comparison community. When Aboriginal people themselves control and maintain ownership of community-based intervention programs, nutritional improvements can be initiated and sustained.
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We have developed a new procedure (Vir typing) for typing Streptococcus pyogenes, by amplifying the entire 5- to 7-kb variable vir regulon by long PCR. The amplified DNA is then cleaved with HaeIII and visualized by ethidium bromide fluorescence after agarose gel electrophoresis. A simple procedure for preparing DNA of sufficiently high quality from 96 samples was employed simultaneously. This DNA was also used to develop a random amplified polymorphic DNA (RAPD) procedure. The discriminatory power of the two DNA-based procedures was compared with previous methods, M typing, and multilocus enzyme electrophoresis. Both procedures were highly discriminatory, but the stoichiometric yield of restriction fragments in Vir typing allows unambiguous interpretation of results.
PCR-ribotyping, a new typing method based on long PCR, has been developed for nontypeable Haemophilus influenzae (NTHi). Ribosomal operons of NTHi were amplified by long PCR and were found to be highly polymorphic for internal HaeIII sites. The technique was applied to 49 isolates previously subjected to conventional ribotyping, and the two methods showed a high level of concordance for serial isolates from individual subjects. PCR-ribotyping provides a powerful new typing tool for strain characterization in epidemiological investigations of NTHi.
A molecular technique (random amplification of polymorphic DNA) was used to characterize group A streptococcal (GAS) strains among 194 isolates from 55 swabs from 12 Australian Aboriginal children and adults with multiple pyoderma lesions. Ninety-three percent of the lesions contained only one strain of GAS, but 8 of 12 individuals were infected with more than one strain. We conclude that accurate epidemiologic surveys require that more than one swab specimen be obtained from each person, whereas typing of more than one colony per swab is less informative. Characterization of GAS strains by random amplification of polymorphic DNA analysis should help to provide important insights into the epidemiology of GAS, particularly in tropical populations where many isolates are M nontypeable, and into the mechanisms of genetic variation of GAS in such populations.
Twenty-two reference isolates and 30 local isolates of group A Streptococci were classified into 36 electrophoretic types (ET) on the basis of allozyme variation at 27 enzyme loci. Local isolates were characterized by a high frequency of M-non typable strains. M-type and ET were more closely associated in local isolates from an endemically-infected population; nevertheless, amongst the local isolates there were also strains of the same ET type with different M-types. A possible explanation is that genetic exchange between strains may introduce different M-types into strains of defined ET when these are exposed to strong selection in the presence of heavy loads of infection. In contrast to the reported clustering of strains associated with toxic shock-like syndrome into two closely related ET clones, we found no relationship of ET phenotype to acute poststreptococcal glomerulonephritis or rheumatic fever.
Otitis media (OM) develops in the first months of life and persists throughout childhood in many rural Aboriginal children. We have followed Aboriginal and non-Aboriginal infants from birth to determine the relationship of the early onset of OM to nasopharyngeal colonization with respiratory pathogens. Aboriginal infants were colonized with multiple species of respiratory bacteria (Moraxella catarrhalis, Haemophilus influenzae, Streptococcus pneumoniae) at a rate of 5% per day and the timing of colonization predicted the onset of persistent OM in individual Aboriginal infants. Non-Aboriginal infants became colonized by M. catarrhalis alone at the slower rate of 1% per day and experienced transient episodes of OM in the absence of colonization. We attribute early bacterial colonization in most Aboriginal infants to high rates of cross-infection due to overcrowding, poor hygiene and high rates of bacterial carriage. Early age of infection and the multiplicity of bacterial types may contribute to prolonged carriage and to eustachian tube damage leading to persistent OM. Thus Aboriginal infants are "otitis-prone" and might qualify for prophylactic antibiotics.
This paper addresses the conceptual and methodological difficulties in obtaining reliable information on alcohol-related mortality in Aboriginal communities. A working definition is proposed; this requires an alcohol-positive history together with a consistent mode of death, and is applied retrospectively to a series of 29 adult deaths in a large Aboriginal community. An informant history of alcohol abuse was found to be the most sensitive indicator of an alcohol-positive history and correlated well with autopsy findings and medical records. Alcohol-positive histories were found for 17 of 29 deaths by informant history, for 9 of 29 by autopsy findings, and for 12 of 29 by medical record review. These indicators were combined with a mode of death categorisation to arrive at an estimate of 5 of 29 definite, 5 of 29 probable, and 1 of 29 possible alcohol-related deaths. We conclude by examining the process by which such a definition might be further developed and the context in which resulting information might then be used.
Apparent per capita food and nutrient intake in six remote Australian Aboriginal communities using the 'store-turnover' method is described. The method is based on the analysis of community-store food invoices. The face validity of the method supports the notion that, under the unique circumstances of remote Aboriginal communities, the turnover of foodstuffs from the community store is a useful measure of apparent dietary intake for the community as a whole. In all Aboriginal communities studied, the apparent intake of energy, sugars and fat was excessive, while the apparent intake of dietary fibre and several nutrients, including folic acid, was low. White sugar, flour, bread and meat provided in excess of 50 per cent of the apparent total energy intake. Of the apparent high fat intake, fatty meats contributed nearly 40 per cent in northern coastal communities and over 60 per cent in central desert communities. Sixty per cent of the apparent high intake of sugars was derived from sugar per se in both regions. Compared with national Australian apparent consumption data, intakes of sugar, white flour and sweetened carbonated beverages were much higher in Aboriginal communities, and intakes of wholemeal bread, fruit and vegetables were much lower. Results of the store-turnover method have important implications for community-based nutrition intervention programs.
The poor nutritional status of Aboriginal Australians is a serious and complex public health concern. We describe an unusually successful health and nutrition project initiated by the people of Minjilang, which was developed, implemented and evaluated with the community. Apparent community dietary intake, assessed by the 'store-turnover' method, and biochemical, anthropometric and haematological indicators of health and nutritional status were measured before intervention and at three-monthly intervals during the intervention year. Following intervention, there was a significant decrease in dietary intake of sugar and saturated fat, an increase in micronutrient density, corresponding improvements in biochemical indices (for example, a 12 per cent decrease in mean serum cholesterol, increases in serum and red cell folate, serum vitamin B6 and plasma ascorbic acid), decrease in mean systolic and diastolic blood pressures, a normalisation of body mass index, and a normalisation of haematologic indices. The success of this project demonstrates that Aboriginal communities can bring about improvements in their generally poor nutritional status, and that the store-turnover method provides a valid, inexpensive and noninvasive method for evaluating the resultant changes in community diet. Although the project was undoubtedly effective in the short term, further work is in progress to assess individual strategies with respect to sustainability, cost-effectiveness and generalisability.
We identified incident cases of primary hepatocellular carcinoma (PHC) in the Northern Territory from 1980 to 1989: there were 18 Aboriginal and six non-Aboriginal cases, yielding incidence rates of 5.2 per 100,000 (Aboriginal) and 0.5 per 100,000 (non-Aboriginal) with a relative risk of 10.4 (95 per cent confidence interval (CI) 4.0 to 26.6). The carcinoma was more frequent in males (2.3 per 100,000) than in females (0.7 per 100,000), with a relative risk of 3.4 (CI 1.3 to 9.3). Incidence increased with age; the trend was statistically significant in Aborigines (chi 2(1) = 4.7, P < 0.05) but not in non-Aborigines (chi 2(1) = 3.4, P > 0.05). Hepatitis B virus (HBV) serology was available for 11 Aboriginal and four non-Aboriginal cases; seven of the Aboriginal cases and two of the non-Aboriginal cases were positive for hepatitis B surface antigen (HBsAg). The prevalence of HBsAg in Aboriginal patients with the carcinoma (63.6 per cent) was much higher than that (13.1 per cent) in Aborigines surveyed from communities in the Northern Territory (chi 2(1) = 21.7, P < 0.001). Our results show that the age-specific incidence of PHC in Aborigines in the Northern Territory (30.9 for ages 40 and over) is comparable to that in high-incidence countries such as China (36.9 for ages 40 and over), and that hepatitis B is of major aetiological importance in the Aboriginal population. This underlines the importance of universal immunisation for prevention of HBV infection and for long-term prevention of PHC.
OBJECTIVES: To explore the apparent excess of renal disease in a coastal Aboriginal community in the Northern Territory and to explore its familial basis. DESIGN: Families were ascertained through probands with significant proteinuria. Controls were selected from unrelated subjects living with these families. PARTICIPANTS: All surviving grandparents, parents, siblings, children and grandchildren of 16 probands were studied; there were 219 participants in all, including 58 adult control subjects. MAIN OUTCOME MEASURES: Anthropometric data included the body mass index (BMI), and resting blood pressure. Urinary protein and creatinine levels were measured and urine was examined microscopically for glomerular haematuria (more than 10 red blood cells per microL, with at least 20% dysmorphic red cells). Two hours after a 75 g glucose drink, venous blood was taken and analysed for biochemical markers including urea, creatinine, glucose and gamma-glutamyltransferase. RESULTS: Significant proteinuria (protein to creatinine ratio greater than 50 mg/mmol), provided evidence of renal disease in 30% of both case relatives and control subjects. The prevalence of proteinuria was associated with increasing age, increasing diastolic blood pressure, increasing glucose level and female sex. However, two contrasting groups of subjects were identified in that relatives of probands had more glomerular haematuria than controls (27/112 v. 3/58, P = 0.005) and this was most marked in a family with multiple probands and in the parents of probands; in contrast, controls were more likely to have hypertension and obesity. Diabetes was highly prevalent in adult study subjects (12.4%) with no difference between controls and relatives of probands. CONCLUSIONS: The very high prevalence of renal disease in Australian Aborigines parallels the situation in American Indian communities undergoing rapid cultural change. In the island Aboriginal community studied, proteinuria and glomerular haematuria are familial, possibly due to genetically influenced glomerulonephritis evoked by (unknown) environmental factors. Proteinuria associated with obesity, hypertension and diabetes is less obviously familial, and plausibly related to poor nutrition and other lifestyle factors. The high prevalence of proteinuria and other risk factors in community-based studies and the high incidence of end-stage renal disease show that there is an urgent need for effective education and prevention programs, for more active treatment of hypertension, and for further work to clarify the aetiology and pathogenesis of renal disease in Aboriginal communities.
The apparent incidence of acute hepatitis B infection in the Top End of the Northern Territory was estimated from notification data and hospital data to be 12 per 100,000 per year, with a marked difference between Aborigines (42 per 100,000) and non-Aborigines (4 per 100,000), and an odds ratio of 9.7 (95 per cent confidence intervals 3 to 33). Sixty percent of Aboriginal cases of acute hepatitis B occurred in children under 10 years of age, whereas non-Aboriginal cases occurred in adults aged 20 to 29, most with behavioural risk factors. These findings confirm the importance of immunising Aboriginal children to reduce the future incidence of hepatitis B infection and hepatoma.
OBJECTIVE: To measure the prevalence of hepatitis B virus (HBV) infection in children and staff at Northern Territory schools. DESIGN: Children in Years 5-7 in 24 selected primary schools were invited, with parental consent, to provide demographic and ethnic details, and a capillary blood sample for tests for hepatitis B surface antigen (HBsAg) and antibody to hepatitis B surface antigen (anti-HBs). School staff participated on a similar basis. PARTICIPANTS: 1104 children, comprising 556 from ethnic groups (originating from the United Kingdom, Ireland and northern Europe) previously reported as "low HBV prevalence", 439 Aboriginal Australians, and 109 from "other" ethnic groups (originating from Asia, the Pacific, the Middle East and southern Europe); and 209 school staff, comprising 180 from "low HBV prevalence" ethnic groups, and 29 from Aboriginal and other ethnic groups. RESULTS: Prior HBV infection (i.e. serum positive for HBsAg or anti-HBs) was detected in 28.7% of children (46.9% of 439 Aborigines; 13.7% of the 556 children from the "low prevalence" groups and 32.1% of the 109 from the "other" groups). HBsAg was detected in 8.2% of Aboriginal children, in 0.36% of those from "low prevalence" groups, and in 1.8% of those from the "other" groups. Aboriginal children in rural schools had the highest prevalence of HBV: 5.4% were positive for both HBsAg and anti-HBs, and an additional 9.8% were positive for HBsAg alone. In urban schools, the prevalence was highest in the "other" ethnic groups. For school staff, the prevalence of HBV infection was 12.8% for those from "low prevalence" ethnic groups, and 37.9% for those from all remaining groups (including Aborigines). CONCLUSION: In the Northern Territory the prevalence of past HBV infection is high in children and school staff from ethnic groups previously known to be at higher risk of HBV infection. For students and staff from ethnic backgrounds expected to be at low risk, HBV prevalence is greater than in individuals from similar backgrounds in other parts of Australia. HBV vaccination is now offered to all infants in the Northern Territory. These results also provide a rationale for the more widespread use of HBV vaccine in other situations where significant HBV transmission might occur.