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Biomedical subjects

R B Elliott

Publications and source records attributed to R B Elliott.

At least 73 records · Page 4Linked to original sources

Dietary protein: a trigger of insulin-dependent diabetes in the BB rat?

Animals from a colony of spontaneously diabetic insulin-dependent BB rats were fed from weaning with semi-synthetic diets in which natural proteins were replaced by l-amino acids with or without the addition of either milk or wheat proteins. The normal 50% incidence of diabetes in the colony was reduced to 15% in rats fed the basic semi-synthetic diet, while it was 35% and 52% when supplemented with gluten or milk, respectively. Thus, dietary factors might precipitate the expression of the disease.

Age Factors↗

Cystic fibrosis.

Explore the source record for details and available documents.

Adolescent↗

Diabetic autonomic neuropathy in children: immediate heart-rate response to standing.

The immediate heart-rate response to standing was used to investigate possible autonomic neuropathy in a group of 38 insulin-dependent diabetic patients in the paediatric age group. The controls and most of the diabetics showed the characteristic response to standing of a rapid increase in heart-rate and a fall to the resting rate within 15 seconds. Some diabetics showed a flat response or a prolonged gradual increase of heart-rate on standing. The usual method of describing the change in heart rate that occurs in response to standing is to compare the R-R intervals at the 30th and 15th beats (30:15 ratio). This is considered less appropriate in children because of the wider variability in heart rate due to sinus arrhythmia. An alternative ratio, the "maximum R-R/minimum R-R ratio" is proposed. This ratio is calculated by dividing the length of the maximum R-R interval (which occurred after the minimum R-R interval during the 30 second recording) by the length of the minimum R-R interval. Compared to 38 index-selected age and sex matched controls, the diabetics showed a significantly lower mean "maximum R-R/minimum R-R ratio (P = 0.033). Six of the diabetics had results lower than the lowest control result. This test gives a prevalence rate of changes suggestive of diabetic autonomic neuropathy of approximately 15% in this age group.

Adolescent↗

Evidence for independent regulation of human erythrocyte and adipocyte insulin receptors.

Specific binding of [125I]-insulin was measured in erythrocytes and fat obtained at the time of mastectomy in twenty-three subjects. There was a significant negative correlation between the level of specific binding to fat and fasting insulin concentration (r=0.55, p less than 0.05, n=23) suggesting down-regulation of fat insulin level by insulin. Insulin binding to erythrocytes did not correlate with insulin nor was there any relationship between insulin binding to erythrocytes and fat from the same subject. Thus while the erythrocyte insulin receptor may be of interest in its own right, it may not be subject to the normal regulatory influences seen in classical insulin target tissues. Insulin binding to erythrocytes may therefore be invalid as a model to study down-regulation of insulin receptors.

Adipose Tissue↗

Hospital admissions for asthma in children: a prospective study.

One hundred consecutive admissions to hospital for asthma in children aged three to 14 were studied prospectively. There was considerable morbidity in these patients; the mean number of admissions for asthma was 5.7 and 46 percent of patients of school age had issued four weeks or more in the previous 12 months due to asthma. 27 percent of the patients were Polynesian Pacific Islanders (PI) compared to 7 percent in the Auckland urban areas (p less than 0.01). PI were readmitted more frequently during the study period compared to Europeans (p less than 0.005). No difference in the general form of asthma was seen between ethnic groups. However, there were marked socioeconomic differences implied by lower home ownership, larger families and relative overcrowding in the home of PI. The higher admission rates of PI may be related to these and to lower drug usage, in particular fewer patients were using sodium cromoglycate and different admission criteria.

Adolescent↗

Neonatal screening for cystic fibrosis, using immunoreactive trypsin assay in dried blood spots.

Our previous studies suggested that assay of immunoreactive trypsin (IRT) in dried blood spots might be a valuable neonatal screening test for cystic fibrosis (CF). We have developed a convenient, sensitive, human trypsin radioimmunoassay, which uses a 3-mm diameter disc of dried blood. The molecular species assayed in blood is trypsinogen. A retrospective study of 24 known cases of CF and appropriate controls confirmed that an elevated blood level of IRT is characteristic of all newborn CF infants, whether or not they have residual exocrine pancreatic function. IRT levels did, however, decline with time of sample storage. Guthrie cards from 5040 newborns were prospectively assayed: 2% of tests were reassayed because of elevated IRT. Thirty-three second samples (0.67% of the total) were requested, 32 were received, and 31 had normal IRT values. The baby with an elevated result had no clinical symptoms of CF at one month of age, normal stool trypsin activity, but 2 sweat tests gave grossly abnormal results. In contrast, a second infant in whom CF was diagnosed around the same time, had a similar 5-day blood spot IRT value, but severe clinical symptoms of CF and no stool trypsin activity. No false negatives are yet known. We conclude that blood spot IRT assay is a reliable and convenient neonatal screening test for CF.

Clinical Enzyme Tests↗

Comparative studies on the hemodynamic effects of prostaglandin E1 prostacyclin, and tolazoline upon elevated pulmonary vascular resistance in neonatal swine.

Forty-eight hour old anesthetised and ventilated neonatal piglets were cannulated in order to measure pressure, blood gases and cardiac outputs (CO) from which pulmonary (PVR) and systemic (SVR) vascular resistances were calculated. After baseline measurements had been made inspired gases were altered to produce hypoxemia and hypercapnia, to raise PVR. Animals then received Prostaglandin E1 (PGE1), Tolazoline (TOL), and Prostacyclin (PGI2) in varying dosages until PVR was reduced or the dosage no longer tolerated. With "hypoxia" CO, PVR and pulmonary artery (PA) pressures rose; aortic pressure also rose although SVR tended to fall. PGE1 (5microgram/kg/min) and PGI2 (1.0 microgram/kg/min) both produced a significant fall in PVR. The decrease in PVR with TOL (1 mg/kg/10 minutes and 2 mg/kg/1 hour) was less consistent and in surviving animals did not achieve statistical significance by multivariate analysis. SVR fell with all drugs although the change with TOL was again non-significant. With both PGI2 and TOL there was a trend for CO to rise and, although this did not reach significant levels, it restricted the drop in arterial pressure to approximately control levels. The fall in arterial pressure with PGE1 was greater. The death rate with treatment with TOL was much higher than that seen with the other two drugs. Circulatory changes in a group of animals with normal blood gases treated with PGI2 (1 microgram/kg/min) were similar to those seen with the hypoxic group.

Alprostadil↗