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Biomedical subjects

R Jackson

Publications and source records attributed to R Jackson.

At least 19 recordsLinked to original sources
PubMed1992

Does recent alcohol consumption reduce the risk of acute myocardial infarction and coronary death in regular drinkers?

This study, conducted in Auckland, New Zealand, over 2 years from March 1986, used a case-control design to investigate the hypothesis that alcohol acutely increases the risk of both nonfatal myocardial infarction and coronary death in the 24 hours after drinking, among regular drinkers. The nonfatal myocardial infarction analyses included 278 male and 60 female cases identified from a population-based coronary heart disease surveillance program and 458 male and 266 female controls randomly selected from the same population matched by age and sex. In the coronary death analyses, 172 male and 16 female coronary death cases from the same surveillance program and a population-based sample of 294 males and 165 females who were age and sex matched were examined. Information on alcohol consumption in the 24 hours before the coronary event in cases and a comparable 24-hour period in controls was collected. Study subjects all drank alcohol regularly at least once per month and were aged 25-64 years. Controls were more likely than cases to report a drinking episode in the 24-hour period examined in both sexes and for fatal and nonfatal disease. After controlling for possible confounding, the authors found that drinkers had a consistently lower estimated risk of both fatal and nonfatal coronary heart disease than participants reporting no alcohol in the previous 24 hours. The odds ratios ranged from 0.75 (95% confidence interval 0.62-0.90) for nonfatal myocardial infarction in men to 0.46 (95% confidence interval 0.19-1.10) for coronary death in women. There were no clear differences in estimated acute risk among those who drank one or two drinks, three or four drinks, or more than four drinks in the 24-hour period. These findings suggest that, contrary to previous speculation, alcohol consumption may acutely reduce coronary heart disease risk.

Adult↗
PubMed1992

The bisphosphonate, alendronate, prevents bone loss in ovariectomized baboons.

We examined the effect of the amino bisphosphonate alendronate, administered IV every 2 weeks at 0.05 and 0.25 mg/kg for 1 year, on bone loss and parameters related to bone metabolism in ovariectomized baboons. Relative to non-OVX animals, the OVX baboons experienced increased bone turnover, reflected in biochemical and histomorphometric measurements, and bone loss assessed by dual-beam absorptiometry in the lumbar spine, which was similar to changes observed in ovariectomized women. Alendronate treatment maintained all parameters of bone turnover at control (nonovariectomized) levels and prevented the bone loss in a dose-dependent manner. We concluded that ovariectomized baboons offer a suitable model for the bone changes observed in ovariectomized women and that these changes can be prevented by sustained administration of an appropriate dose of this aminobisphosphonate.

Acid Phosphatase↗
PubMed1992

The renin-secreting cell and the glomerular peripolar cell in renal artery stenosis and Addison's disease.

The glomerular peripolar cell may be a secretory component of the juxtaglomerular apparatus. To investigate this hypothesis we studied kidneys with the renin-angiotensin system activated by two different stimuli in order to compare the responses of peripolar cells and renin-secreting cells. We examined 10 human kidneys, removed for renal artery stenosis and 11 autopsy cases of Addison's disease with appropriate controls. We counted granulated peripolar cells in serial paraffin-embedded sections and renin-containing cells were quantified using an immunoperoxidase technique with an antiserum to human renin. There was a five-fold increase in the number of renin-containing cells in both renal artery stenosis and in untreated, but not in treated, Addison's disease. Peripolar cells were increased in number in three cases of renal artery stenosis, but were unaltered in both treated and untreated Addison's disease. Therefore, neither a reduction in renal perfusion pressure (renal artery stenosis), nor sodium depletion (Addison's disease) consistently affect peripolar cells in humans. These findings do not support the hypothesis that the peripolar cell is part of the juxtaglomerular apparatus.

Addison Disease↗
PubMed1992

Plasma 25-hydroxyvitamin D3 and its relation to physical activity and other heart disease risk factors in the general population.

The relation between plasma levels of 25-hydroxyvitamin D3, the main metabolite of sun-induced vitamin D, and major coronary heart disease risk factors was examined in 295 men, aged 35 to 64 years, who were randomly sampled from the general population. Men who did regular vigorous leisure-time activity had a mean plasma 25-hydroxyvitamin D3 level that was 4.8 nmol/L (95% confidence limits: 0.1, 9.5) higher than that in inactive men, with the increase greatest in the winter months. Plasma 25-hydroxyvitamin D3 was positively associated with weekly hours of sun exposure (r = 0.27, P < 0.01), and showed a weak inverse association with age (r = -0.12, P < 0.05) and diastolic blood pressure (r = -0.15, P < 0.05), although this latter finding was no longer significant when allowance was made for the effects of age and season on vitamin D levels. In contrast, plasma 25-hydroxyvitamin D3 had no relation with either serum total or high-density-lipoprotein cholesterol levels, body mass index, or cigarette smoking. We hypothesize that vigorous leisure-time activity may protect against coronary heart disease, in part, by increasing body levels of vitamin D.

Adult↗
PubMed1992

Glomerular basement membrane thinning in adults: clinicopathological correlations of a new diagnostic approach.

We have studied glomerular basal laminar thickness in biopsy material, using a simple technique involving 16 selected measurements per case. Twenty-nine biopsied cases of adult glomerular haematuria were examined together with 'diseased' controls represented by a variety of glomerulopathies including minimal-change disease and IgA nephropathy. 'Normal' control populations were provided by 13 patients with acute-onset renal failure of non-glomerular origin and nine patients undergoing nephrectomy. Analysis of groups determined by the presence or absence of haematuria, the degree of proteinuria and presence or absence of a diagnostically characteristic immunofluorescence pattern showed that the nine patients with haematuria and proteinuria of less than 200 mg/24 h represented a distinct subpopulation with a mean membrane thickness of 225 nm compared to the control mean of 343 nm (P less than 0.0001). All members of this subpopulation had mean values below an arbitrary cut-off value of 270 nm. Within other specific disease categories, sporadic cases had mean membrane thicknesses below this critical value, indicative of an overlap of pathologies. On short-term follow-up there is no evidence that the 'pure' thin-membrane population are subject to any deterioration in renal function. It is of further interest that eight of nine thin-membrane 'syndrome' cases were O Rh positive. This finding may provide a starting point for investigation of a specific genetic defect.

ABO Blood-Group System↗
PubMed1992

Early aortic valve cusp rupture in relapsing polychondritis.

Aortic regurgitation associated with relapsing polychondritis usually occurs late in the disease as a result of aortic root dilatation. A case where aortic regurgitation occurred early and was due to cusp rupture with a normal aortic root is reported. The patient required urgent aortic valve replacement within six weeks of developing a murmur despite apparent control of inflammation with immunosuppressive treatment. The possibility of cusp rupture with sudden haemodynamic deterioration should be considered in patients with relapsing polychondritis who develop aortic regurgitation.

Aortic Valve↗
PubMed1992

Cauda equina syndrome secondary to an improperly placed nucleotome probe.

Automated percutaneous lumbar discectomy has been shown to be a low morbidity procedure in the treatment of contained herniated lumbar discs. Described in this paper is a complication, i.e., a cauda equina syndrome secondary to a Nucleotome probe improperly placed in the thecal sac. The authors reemphasize the landmarks for the thecal sac, i.e., the medial border of the pedicles, and discuss the preventable nature of this type of complication.

Adult↗
PubMed1992

The effect of intermediate altitude on the Army Physical Fitness Test.

Official physical training records of personnel stationed at intermediate altitude (elevation 5,280 feet) for at least 1 year were reviewed to gauge the effect of altitude on 2-mile running performance. An average of 48 additional seconds (a 5% increase in time) was required to complete the run compared to sea-level values in the same subjects. Run times gradually diminished during the first 9 months of assignment to altitude before stability was established. These data indicate that acclimatization occurs over several months. Even with acclimatization, substantial loss of performance is associated with habitation at intermediate altitude.

Adult↗
PubMed1992

Efficacy of antiperspirants on feet.

Nineteen male soldiers participated in a study of the effectiveness of two antiperspirants (aluminum chlorohydrate and aluminum zirconium tetrachlorohydrex glycine) in reducing foot-sweat accumulation and injuries. Each subject was tested before and after antiperspirant application, with a 1-hour treadmill march at 5.6 km/hour in a warm environment. Both antiperspirants decreased (p less than 0.05) foot-sweat accumulation over 50%. There was also a tendency, although not statistically significant, for subjects to incur fewer blisters with antiperspirant use. However, the antiperspirants also increased (p less than 0.05) the incidence of irritant dermatitis. Nevertheless, these data suggest that the application of antiperspirants to the feet has merit in reducing serious foot injuries (blisters, trench foot) exacerbated by wet feet.

Adult↗
PubMed1991

Mortality from coronary heart disease and incidence of acute myocardial infarction in Auckland, Newcastle and Perth.

OBJECTIVE: To confirm the existence of regional differences in coronary death rates in Australia and New Zealand and to determine whether or not these are associated with parallel differences in the incidence of acute myocardial infarction. DESIGN: Descriptive epidemiological study. SETTING: Community based study. SUBJECTS: Residents of Auckland, Newcastle and Perth aged 25-64 years admitted to hospital for acute myocardial infarction or dying from coronary heart disease between 1983 and 1987. MAIN OUTCOME MEASURES: Definite acute myocardial infarction or coronary death classified according to the criteria of the World Health Organization MONICA project. RESULTS: This study confirms the marked variation, evident from official statistics, in mortality rates from ischaemic heart disease between Newcastle (high), Auckland and Perth (low). A different pattern is observed for the incidence of acute myocardial infarction and there are also obvious differences between centres in the case fatality ratios for all acute coronary events combined. Newcastle has the highest rate for all coronary events, particularly in women. Auckland is characterised by substantially higher case fatality ratios compared with the two Australian cities. This is due especially to higher rates of coronary death outside hospital. Perth, which has the lowest mortality rates and case fatality ratios in both men and women, has rates for admission to hospital for acute myocardial infarction and all cases of ischaemic heart disease that are disproportionately high in relation to the corresponding mortality rates. CONCLUSION: The differences in case fatality ratios between these three centres are not readily explained by artefacts related to enumeration or classification. Rather, they are most likely related to differences in the natural history of ischaemic heart disease in the three populations. Differences in medical management may also contribute to the substantial variation in mortality rates.

Adult↗
PubMed1991

Alcohol consumption and risk of coronary heart disease.

OBJECTIVE: To investigate the hypothesis that the apparent protective effect of habitual alcohol consumption on coronary heart disease is due to drinkers at high risk of coronary heart disease becoming non-drinkers. DESIGN: Case-control population based study. Data were obtained from interviews with patients with non-fatal myocardial infarction and their controls and with the next of kin of those who had died of coronary heart disease and their controls. SETTING: Auckland, New Zealand. SUBJECTS: Two groups of cases were studied. The first comprised 227 men and 72 women with non-fatal myocardial infarction identified from a population based surveillance programme for coronary heart disease; controls were 525 men and 341 women randomly selected from the same population group and matched for age and sex. The second group comprised 128 men and 30 women who had died of coronary heart disease and had been identified from the surveillance programme; controls were a sample of the previous control group and comprised 330 men and 214 women matched for age and sex. All participants were aged 25-64 years and without diagnosed coronary heart disease. MAIN OUTCOME MEASURES: Regular alcohol consumption; high density lipoprotein cholesterol and low density lipoprotein concentrations. RESULTS: Men with myocardial infarction and men who had died of coronary heart disease were more likely to have been never drinkers (had never drunk more than once a month) than controls (18% v 12% and 23% v 13% respectively). After possible confounding factors had been controlled for, people in all categories of drinking (up to more than 56 drinks per week) had at least a 40% reduction in risk of fatal and non-fatal coronary heart disease compared with never drinkers. Former drinkers also had a lower risk of non-fatal myocardial infarction than never drinkers (relative risks 0.41 and 0.10 in men and women respectively) but a similar risk of death from coronary heart disease. The reduction in risk was consistently greater in women than in men in all drinking categories but there was no clear dose-response effect in either sex. CONCLUSIONS: The results support the hypothesis that light and moderate alcohol consumption reduces the risk of coronary heart disease. This protective effect in this population was not due to the misclassification of former drinkers with a high risk of coronary heart disease as non-drinkers.

Adult↗
PubMed1991

The diet of Auckland men and women aged 25-64 years.

The dietary intake of a sample of 537 men and 372 women aged 25-64 years, randomly selected from the Auckland general electoral rolls, was assessed in order to describe current nutritional patterns in Auckland and to compare dietary intakes between men and women. A 118 item food frequency questionnaire was given to each participant to recall usual intake over the previous three months. After adjusting for energy intake, men consumed significantly more fat and cholesterol than women, consistent with their increased intake of red meat (median serves per month = 28 for men, 23 for women) and their greater tendency to eat fried meat (80.3% v 71.7%) and to drink full cream milk (82.7% v 70.7%). In contrast, women consumed more carbohydrate and fibre than men after adjusting for energy, consistent with their increased intake of vegetables (median serves per month = 136 for women, 116 for men) and fruit (median serves per month = 71 for women, 39 for men). These dietary differences between men and women may partly explain the increased coronary heart disease rates in men.

Adult↗