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Biomedical subjects

M Ball

Publications and source records attributed to M Ball.

At least 73 records · Page 4Linked to original sources
PubMed1993

Increasing calcium intake in women on a low-fat diet.

Dietary advice to reduce the risk of coronary heart disease (CHD) is aimed at reducing saturated fat intake, especially in people with hyperlipidaemia. Dairy products contribute a considerable proportion of the fat intake of many people's diet in New Zealand, and are thus often reduced. However, dairy products provide about 60% of the dietary calcium. This study investigated the calcium intake of 50 women aged 40-65 years on fat-reduced diets. The effect of giving standardized information on the importance of calcium intake, and on ways to increase this, was assessed by a repeat dietary analysis 3 months later. The mean (SD) calcium intake was initially 696 (245) mg per day; below that recommended for post-menopausal women. The mean percentage energy from fat and saturated fat was 28.5% and 9.6%, respectively. Three months later, after the specific advice on calcium, the mean calcium intake was significantly higher at 938 (317) mg per day, with 88% having increased their intake, yet the intake of energy, fat and saturated fat were unchanged. This was mainly achieved by increased use of low-fat dairy products. Specific advice about calcium should be given to women commencing lipid-lowering diets in order to attain recommended intakes and to reduce the risk of osteoporosis, as well as CHD.

Adult↗
PubMed1992

Androgenic-anabolic steroid abuse and platelet aggregation: a pilot study in weight lifters.

The abuse of anabolic-androgenic steroids by athletes has recently been associated with the development of myocardial infarction and stroke. Because platelets play a pathogenic role in these disorders, the authors hypothesized that androgenic steroid abuse among weight lifters was associated with increased platelet aggregation as measured in vitro. Twenty-eight study participants were recruited. Twelve denied current androgen use. However, 8 of these 12 tested positive for urinary androgens. Nonsignificant trends toward increased platelet counts and increased platelet aggregation to adenosine diphosphate were noted when androgen users were compared to nonusers. However, when stratified by age, older (greater than 22 years) androgen users required lower concentrations of collagen to produce 50% aggregation of test platelets than did younger (less than or equal to 22 years) androgen users (1.47 versus 3.35 micrograms/ml; p = .01). Further subgroup analysis revealed nonsignificant trends toward increased adenosine diphosphate-induced aggregability and nonsignificant trends in the platelet count in older weight lifters. Subsequent studies using collagen threshold aggregometry revealed no age-dependent effect in 17 other men (aged 18 to 46 years) not specifically selected for activity (r = .17). This study suggests an association between androgen use, age, and increased platelet sensitivity to collagen in weight lifters and may be helpful in explaining recent thrombotic disease in androgen users. It additionally calls into question the validity of subjective reporting when assessing androgen use among weight lifters.

Adolescent↗
PubMed1992

A pre-embedding reaction method for localizing NADH reductase and succinic dehydrogenase in skeletal muscle.

Paraffin wax embedding methods suitable for demonstrating the distribution of enzyme activity in tissues sections are uncommon; most procedures rely on the use of frozen section techniques. This paper describes a system for demonstrating certain enzymes which involves incubation of the tissue with appropriate substrates before a Paramat wax embedding procedure. While it has distinct merits of its own, the procedure is eminently suitable for use where a cryostat is not available; it can also be readily applied to other enzymes and tissues.

Animals↗
PubMed1992

Should mono- or poly-unsaturated fats replace saturated fat in the diet?

The effects of diets differing in saturated, monounsaturated and polyunsaturated fatty acid composition (SAFA, MUFA and PUFA, respectively) on plasma lipoproteins and factor VIIc were investigated in 28 middle-aged men and women with mild to moderate hyperlipidaemia. The subjects were stabilized on a diet with a total fat content fairly typical of New Zealand, containing approximately 40% energy as fat, before entering a randomized cross-over trial of diets high in PUFA (20% energy; SAFA and MUFA 10% each) or a high MUFA diet (20% energy; SAFA and PUFA 10% each). After 6-week periods on each diet the subjects returned to a high SAFA diet. Body weight and blood pressure remained unchanged during the study. Total and LDL cholesterol, HDL cholesterol and the HDL2 subfraction were significantly lower on both the MUFA and the PUFA diet than on SAFA. However, there were no statistically significant differences in lipoprotein concentrations on the MUFA and PUFA diet. Factor VIIc concentrations were similar on the three diets. The proportion of PUFA in a MUFA diet appears to be a major determinant of the relative lipoprotein response to such a diet. In order to avoid a reduction in HDL-C when replacing SAFA with MUFA it may be necessary to ensure that PUFA does not provide more than about 8% total energy. Thus careful planning is needed to identify the most appropriate foods to replace those rich in SAFA in diets designed to reduce the lipoprotein-mediated risk of coronary heart disease.

Aged↗
PubMed1991

[Diverse aspects of congenital syphilis].

Together with the new rise of recent syphilis in the adult woman, congenital syphilis reappears sporadically in our countries, where prophylactic measures (prenatal serology) are sometimes defeated. It remains much more frequent in developing countries. One should know how to interpret a positive serology in a newborn, as it may only reflect passive transplacental transfer of maternal antibodies. One should on the other hand think of syphilis again when the clinical signs are more or less suggestive, the typical picture not being, by far, the most frequent. In spite of the efficacy of Penicillin G: 50,000 U/kg/day during 10 days, neonatal death rate for congenital syphilis is in the neighbourhood of 10%. Our major effort should therefore be aimed at prevention.

Female↗
PubMed1990

Glycerophosphoethanolamine concentration is elevated in brain of patients with dominantly inherited olivopontocerebellar atrophy.

We measured the concentration of glycerophosphoethanolamine (GPEA), a membrane breakdown product, in autopsied brain of 10 patients with dominantly inherited olivopontocerebellar atrophy (OPCA), a cerebellar ataxia disorder. As compared with the controls, mean GPEA levels were significantly elevated by 37-69% in 11 of the 15 brain areas examined, including extracerebellar brain regions in which no neuronal cell loss could be detected by semiquantitative estimation. Our data suggest the possibility of altered membrane phospholipid metabolism in OPCA which could be a contributing factor in the neuronal cell death.

Adult↗
PubMed1990

Hyperlipidaemia in general practice: three year follow up of an opportunistic screening project.

As part of the national lipid screening project 927 people with a plasma cholesterol level greater than 6.5 mM were detected by screening 4006 men and women aged 25-59 years. Three years later 801 of the 878 patients eligible for a follow-up study (91%) had been followed up at least once. The median number of follow-up visits was two. The bulk of the workload fell on the nursing staff. The mean decrease in cholesterol level was 8-14% in those receiving dietary advice only, 15-25% in those receiving additional drug treatment and 12% for all patients. A proportion of this decrease must be attributable to regression to the mean, loss to follow up when patients were doing well, and the patients' knowledge of their follow-up date. Data on a group of patients not attending for regular follow up suggest that regression to the mean could account for up to 7% of the cholesterol reduction observed. Screening for hyperlipidaemia in general practice is feasible when the necessary infrastructure is provided, but even with a fairly conservative protocol 3% of those screened received drug treatment.

Adult↗
PubMed1989

Prescribed fenoterol and death from asthma in New Zealand, 1981-83: case-control study.

A case-control study was conducted to examine the hypothesis that fenoterol by metered dose inhaler (MDI) increases the risk of death in patients with asthma. The case group comprised 117 patients aged 5-45 who died of asthma between August, 1981, and July, 1983. For each case, 4 controls, matched for age and ethnic group, were selected from asthma admissions to hospitals to which the cases themselves would have been admitted, had they survived. The relative risk of asthma death in patients prescribed fenoterol by MDI was 1.55 (95% CI 1.04-2.33, p = 0.03). The possibility of confounding or effect modification by severity was assessed by consideration of subgroups defined by markers of asthma severity. The fenoterol MDI relative risk was 2.21 (95% CI 1.26-3.88, p = 0.01) in patients prescribed three or more categories of asthma drugs, 2.16 (95% CI 1.14-4.11, p = 0.02) in patients with a hospital admission for asthma during the previous 12 months, and 6.45 (95% CI 2.72-15.3, p less than 0.01) in patients prescribed oral corticosteroids at time of death or admission. In the group of patients with the most severe asthma (defined by a hospital admission during the previous year and prescription of oral corticosteroids) the fenoterol MDI relative risk was 13.29 (95% CI 3.45-51.2, p less than 0.01). After adjustment for severity, no other asthma treatment commonly used in New Zealand seemed to be associated with an increased risk of asthma death. Not all sources of bias can be definitely excluded; however, when considered together with other epidemiological and experimental evidence, these findings are consistent with the hypothesis that use of fenoterol by MDI increases the risk of death in severe asthma.

Acute Disease↗
PubMed1989

Serum lipid response to dietary cholesterol in subjects fed a low-fat, high-fiber diet.

To determine whether hyperresponse to dietary cholesterol occurs in individuals consuming a low-fat diet, a study was performed on 58 subjects whose plasma cholesterol had changed by greater than or equal to 5% when intakes of two and seven eggs per week were compared in a previous study. Here, the effect of eating nine, zero, and nine eggs per week was studied over 3 consecutive months. Plasma total, LDL, and HDL cholesterol did not differ significantly. There was no correlation between individuals' lipoprotein changes in this and the previous study. Consistent hyperresponse to moderate cholesterol intake is not apparent in people eating a low-fat, high-fiber diet. Reduction in dietary cholesterol below 400 mg/d produces no further substantial cholesterol lowering.

Adult↗
PubMed1988

Optic nerve coloboma associated with renal disease.

Optic nerve colobomas can occur as sporadic abnormalities, may be inherited as an autosomal dominant defect, occur as part of syndromes, and are rarely associated with cardiac malformations and midline encephaloceles. Karcher [1979] described a father and son with the "morning glory" optic disc anomaly and renal disease as a new association. We report on two brothers with optic nerve colobomas associated with renal disease. The ophthalmologic findings and renal histopathology are presented. This second familial occurrence suggests that the association of optic nerve coloboma and renal disease is a newly recognized syndrome.

Child↗
PubMed1988

Characterization of genetic markers in the 3' end of the apo B gene and their use in family and population studies.

The 3' end of the apo B gene is highly polymorphic. Two point mutations in the coding sequence of the gene create EcoRI (E+, E-) and XbaI (X+, X-) RFLPs. The two loci are in random association and the frequency of the four haplotypes, E+X+, E+X-, E-X+ and E-X- in the normolipidaemic population are 0.68, 0.30, 0.02 and 0.00, respectively. Although the polymorphic nucleotide underlying the EcoRI RFLP creates an amino acid substitution in the apo B protein (Glu----Lys) in a region close to a putative LDL-receptor recognition site(s), we find no statistically significant difference in the frequency of the apo BGlu and apo BLys alleles in hyperlipidaemic patients (familial hypercholesterolaemia, type IIA with no tendon xanthomas, IIB and probably IV) and the normolipidaemic population. In contrast, we confirm previous findings, that the X+ allele is in linkage disequilibrium with a genetic locus that predisposes to the development of higher fasting plasma triglyceride levels than the X- allele. We have characterized a highly polymorphic region immediately 3' to the apo B gene. At least 5 alleles of this locus exist in the population and our family studies show it should be an extremely informative locus to use in studies where polymorphic or mutant apo B alleles are suspected to underly certain forms of familial hyperlipidaemia. DNA sequence analysis of this highly polymorphic locus shows that the variation is entirely attributable to the number of times the simple repeating sequence 5'-TTTATAATTAAAATATTTATAATTAAATAT-3' is present.

Adult↗