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Biomedical subjects

R J Jarrett

Publications and source records attributed to R J Jarrett.

At least 145 records · Page 8Linked to original sources
PubMed1977

Hyperlipidaemia in children on regular haemodialysis.

Fasting plasma concentrations of triglycerides (TG), cholesterol, immunoreactive insulin (IRI), and blood glucose were raised in 16 children with chronic renal failure on regular haemodialysis compared with 18 healthy children. In the patients plasma IRI correlated positively with plasma TG, while blood glucose did not correlate with IRI or lipid concentrations. Dietary intake, expressed as percentage of recommended intake for height-age, did not correlate with plasma lipids, but there was a positive correlation between plasma TG and the proportion of calories derived from carbohydrate. The children were not malnourished as evidenced by normal plasma albumin and transferrin concentrations. The mechanism of the hyperlipidaemia is unclear but it may be related to the glucose intolerance with hyperinsulinaemia which is found in uraemia. In view of the risk of premature atherosclerosis, plasma lipid concentrations should be monitored in children with chronic renal failure and attempts made to ameliorate hyperlipidaemia with appropriate dietary manipulations.

Adolescent↗
PubMed1976

Smoking and other risk factors for coronary heart-disease in British civil servants.

A five-year follow-up of 18 403 male British civil servants between the age of 40 and 64, who had been the subject of an earlier clinical survey found 277 deaths from coronary heart-disease (C.H.D.). After adjusting for age, current cigarette smoking, systolic and diastolic blood-pressure, and blood-cholesterol were shown to be related to both the prevalence of one or more indices of cardiac ischaemia and to the risk of cardiac death. Neither blood-glucose two hours after a 50 g load nor weight/height showed any such simple linear association with mortality. Multivariate analysis confirmed that the main risk factors were independently related to cardiac morbidity and mortality. Irrespective of blood-pressure or plasma-cholesterol, current cigarette smokers thus had a higher risk of C.H.D. death than those not smoking cigarettes.

Adult↗
PubMed1976

Hyperglycaemia and diabetes mellitus.

Recommended criteria for the diagnosis of maturity-onset diabetes mellitus based on glucose tolerance tests vary considerably; none are derived from long-term observations of the further development of different degrees of glucose intolerance. Evidence from several epidemiological investigations suggests that the risk of specific diabetic complications becomes important only in people with capillary whole-blood sugar concentrations exceeding 200 mg/dl 2 hours after a 50 g oral glucose load, who have overnight fasting blood-sugar concentrations usually exceeding 110 mg/dl. Lesser degrees of glucose intolerance may, nevertheless, indicate an additional risk of atherosclerotic arterial disease. Assessment of "borderline diabetics" should, therefore, include and evaluation of other known risk factors for arterial disease and any treatment programme should be determined in the light of these as well as by the degree of glycaemia.

Adult↗
PubMed1976

Urinary albumin excretion in normal and diabetic subjects.

Using an albumin radio-immuno-assay, urinary albumin concentration and excretion rate have been measured in diabetics and control subjects overnight, after several hours ordinary activity and during two successive one hour periods of recumbency. The urine albumin concentration was relatively constant throughout each of the four collection periods. Variations in albumin excretion rate were directly related to changes in urine flow. In assessing changes in urinary albumin, concentration and urine flow should be reported as well as the calculated albumin excretion rate. In the diabetics, selected for absence of clinical proteinuria, the mean concentration of albumin did not differ significantly from that of the controls. The overnight albumin excretion rate was higher in the diabetics, but this was due to the greater volume of urine.

Albuminuria↗
PubMed1975

Diurnal variation in the effects of insulin on blood glucose, plasma non-esterified fatty acids and growth hormone.

Insulin 0.05 mu/kg body weight was injected intravenously into 14 subjects both at 8 a.m. and 5 p.m. in random order 12 hrs after a 50 g glucose meal. Fasting glucose levels were similar in both cases but the 48percent plus or minus 10 percent fall in blood glucose in the morning was significantly greater (p smaller than 0.001) than that of 34 percent plus or minus 7 percent in the afternoon. Fasting plasma NEFA, however, varied markedly between 477 plus or minus 150 muEqlL in tth morning and 725 plus or minus 195 muEqlL in the afternoon (p smaller than 0.001) and the fall after insulin injection (64 percent plus or minus 14 percent) was greater in the afternoon than in the morning (47 percent plus or minus 15 percent) (p smaller than 0.001). There was an inverse relationship between proportional glucose disappearance and proportional NEFA disappearance (p smaller than 0.001). The calculated caloric change in plasma, the sum of the falls in glucose and NEFA, were very similar in both morning (2.2 plus or minus 0.5 Cals/1) and afternoon (2.3 plus or minus 0.5 Cals/1), i.e., in spite of the variations of glucose and NEFA metabolism produced by insulin at different times, the nett effect, in terms of energy, was the same. Plasma growth hormone response in the afternoon was found to be enhanced compared with the morning values, although the degree of hypoglycaemia was greater in the morning.

Adult↗
PubMed1975

Diurnal and seasonal variation in oral glucose tolerance: studies in the Antarctic.

Oral glucose tolerance tests were performed in 12 young men in the Antarctic. Tests were done in the morning and afternoon at three monthly intervals (March, June, September, December). The characteristic diurnal variation in glucose tolerance persisted throughout the year, but was greater in the warmer months (March and December). There were significant seasonal differences in glucose tolerance; blood glucose values were lowest, both morning and afternoon, in December (midsummer). In one pair of tests performed during a reversal of normal sleep/activity pattern, the direction of the normal diurnal variation of glucose tolerance was also reversed.

Activity Cycles↗
PubMed1974

Diurnal variation in glucose tolerance: associated changes in plasma insulin, growth hormone, and non-esterified fatty acids.

Oral glucose tolerance tests were performed in the morning and afternoon of separate days on 31 people derived from a normal population sample. Blood sugar levels were higher in the afternoon test from and including 60 minutes after the glucose load. The degree of diurnal variation was similar in men and women, but greater in the older half of the group. It was negatively correlated with the degree of obesity. The plasma insulin response was less at the 30 minute time point in the afternoon, but significantly exceeded the morning values at 120 and 150 minutes after the glucose load. Growth hormone levels were similar in morning and afternoon tests. Fasting non-esterified fatty acid levels were significantly higher before the afternoon test.The relatively impaired glucose tolerance in the afternoon is associated with a delayed insulin response to the glucose load. This seems unlikely to be the sole explanation, however, and increased non-esterified fatty acid metabolism with a consequent decrease in glucose disposal may also contribute.

Adult↗
PubMed1974

Diurnal variation in response to intravenous glucose.

Intravenous glucose tolerance tests (25 g) were performed in the morning and afternoon on 13 apparently normal persons. The individual K values (rate of decline of blood sugar) were all higher in the morning tests, and the mean values were significantly higher in the morning. Fasting blood sugar levels were slightly lower in the afternoon. There was no difference between the fasting morning and afternoon plasma insulin levels, but the levels after glucose were lower in the afternoon. Growth hormone levels were low at all times in non-apprehensive subjects and unaffected by glucose. The results suggest that the impaired afternoon intravenous glucose tolerance, like oral glucose tolerance, is associated with impaired insulin release and insulin resistance.

Adult↗