Biomedical subjects

P Aitken

Publications and source records attributed to P Aitken.

21 records · Page 2Linked to original sources

PubMed1982

Differential effects of insulin therapy on hepatic and peripheral insulin sensitivity in Type 2 (non-insulin-dependent) diabetes.

Hepatic glucose production and metabolic clearance rate of glucose were measured using (3-3H) glucose at steady state, basally and during two sequential 2 h insulin (25 and 40 mU . kg -1 . h -1)/glucose (2 and 3 mg. kg -1 . min -1) infusion periods. Eight diabetic subjects were studied before and after 1 week of twice daily insulin therapy; six control subjects matched for age, weight and degree of obesity were also studied. In the diabetic patients, pre-treatment hepatic glucose production was 20.0 +/- 2.2, 9.9 +/- 2.9, and 1.4 +/- 0.8 mu mol . kg -1 . min -1 respectively (+/- SEM) for each of the three periods, and fell significantly with treatment to 12.8 +/- 1.7, 4.0 +/- 1.5 and 1.9 +/- 1.0 mu mol . kg -1 . min -1. Hepatic glucose production in normal subjects was 13.2 +/- 0.6, 2.2 +/- 0.8 and less than 1 mu mol . kg -1 . min -1. The pre-treatment metabolic clearance rate in all diabetic studies with insulin levels greater than or equal to 30 mU/l was 1.10 +/- 0.14 ml . kg -1 . min -1 and remained virtually unchanged following insulin therapy; this was significantly lower than in the control subjects (6.83 +/- 1.02, p less than 0.001). Basal non-esterified fatty acid levels were higher (p less than 0.02) in the pre-treated diabetic patients compared to post-treated diabetic patients and control subjects. Non-esterified fatty acids in each group fell to similar levels during the insulin infusions, but the rate of fall was slower in the pre-treated diabetic patients. Insulin receptor binding to erythrocytes was normal in the diabetic subjects and unchanged by treatment. Therefore, following insulin treatment of uncontrolled Type 2 (non-insulin-dependent) diabetes, the initially increased basal hepatic glucose production, and decreased hepatic sensitivity, return towards normal. However, the glucose clearance remains low, despite good diabetic control, and appears to be a major factor in the continuing glucose intolerance. As insulin receptor binding is normal, the defect of glucose clearance in Type 2 diabetes appears compatible with a post-receptor defect of glucose metabolism.

3-Hydroxybutyric Acid↗

PubMed1982

Validation of a practical in vivo insulin dose-response curve in man.

To adequately investigate the state of insulin resistance, an insulin dose-response curve should be constructed so that insulin sensitivity (right shift of dose-response curve) and insulin responsiveness (maximal response) can be determined. This paper describes and validates in man a practical in vivo insulin dose-response curve technique, using a modification of the euglycaemic clamp described by De Fronzo et al. Insulin action at steady state was expressed as metabolic clearance rate of glucose (MCRG) rather than overall rate of glucose disappearance (M or Rd). MCRG was chosen because at plasma insulin concentrations greater than 25 microunits/ml it was shown (n = 5) not to be altered by changes in blood glucose concentration (MCRG 379 +/- 23 and 408 +/- 19 ml/m2/min; at plasma glucose concentrations 5.4 +/- 0.3 and 10.2 +/- 0.7 respectively), whereas Rd was critically dependent on the prevailing blood glucose concentration (Rd 2007 +/- 128 and 4124 +/- 219 mumol m2/min respectively). MCRG was demonstrated to be stable over a 6 hr period (n = 8) and to be reproducible (n = 4). Insulin dose-response curves (MCRG Versus insulin concentration) were performed on two obese and seven normal weight individuals. The insulin dose-response curves were linearized, allowing accurate prediction of the maximal MCRG, as compared to the experimentally determined maximal response (r = 0.953 p less than 0.01). The use of this transformation obviates the need to employ very high insulin infusion rates to determine the maximal insulin response. In conclusion, the technique permits, in a single 6 hr study, a precise insulin dose-response curve to be constructed for accurately determining insulin sensitivity and responsiveness.

Adult↗

PubMedDate not supplied

GP views of nurse-led telephone referral for paediatric assessment.

Following the introduction of a new nurse-led telephone referral service to a dedicated paediatric emergency assessment unit (PEAU), a study was conducted to determine the views of general practitioners (GPs) who use the service. The PEAU operates between 10 am and 10 pm on weekdays and between 10 am and 6 pm at weekends. The unit has four beds and treatment and stabilization areas, plus associated services in a dedicated area of a regional child health unit. The design utilized a faxed questionnaire over a 1-month period to all consenting GPs using the PEAU with a postal questionnaire follow-up. Non-parametric Likert scores and qualitative data were used to determine levels of satisfaction with the service and the subsequent management of the referred children. Sixty-nine GPs referred 80 children to the PEAU via the service over a period of 1 month. All consented to participate and were sent a faxed questionnaire, which generated 39 (57%) responses. A follow-up questionnaire sent to the 39 respondents achieved a return of 25 (64%) responses. Thirty-four GPs agreed that referral via the dedicated nurse service was easier than the previous senior house officer referral system. Of the 25 GP respondents to the follow-up postal survey, the majority (17) agreed that the follow-up morning after discharge telephone call to parents by the PEAU nurses was helpful. Four GPs indicated that the 24-hour open access system, offered by the nursing staff, in which a parent may attend PEAU with a discharged child causing concern without a previous appointment, does not always work. This study has shown that a nurse-led telephone referral system to a PEAU for GPs and the subsequent management of the children has been favourably received.

Attitude of Health Personnel↗