Insulin infusion systems, diabetic control, and microvascular complications

Adsorption of insulin to the surface of peritoneal dialysis solution containers

Continuous ambulatory peritoneal dialysis (CAPD) is becoming widely used in diabetics with end-stage renal disease. One of the proposed advantages of this technique is the ability to administer insulin intraperitoneally. The administration of insulin by this route provides acceptable plasma glucose control with no need for subcutaneous injections. Because adsorption of insulin to glass and polyvinyl chloride (PVC) surfaces is known to occur with intravenous fluid systems, this study was conducted to measure insulin adsorption to dialysis fluid systems. The effects of time, temperature, heparin concentration, dextrose concentration, and insulin concentration in 2-L glass and PVC dialysis solution containers were studied. While all factors significantly affected adsorption to the PVC containers, the effects of heparin and dextrose were considered to be clinically unimportant. The percentage of insulin adsorbed to the PVC surface increased with increasing time and temperature and decreased with increasing insulin concentrations. Under the conditions studied, 7.1% to 9.6% of insulin added to PVC containers was lost within the first minute. Since 15 to 30 minutes is required by most CAPD patients to prepare and instill the dialysate, 10% to 20% of added insulin may be adsorbed to the PVC bad. The adsorption of insulin to the glass surfaces was rapid with 39.6% to 42.8% being lost within the first minute. All factors studied significantly affected adsorption to the glass, but the effects of time, temperature, dextrose, and heparin were considered to be of minor clinical importance.(ABSTRACT TRUNCATED AT 250 WORDS)

Brittle diabetes: long-term control with a portable, continuous, intravenous insulin infusion system

A young woman had severe brittle diabetes mellitus that was critically unmanageable with all conventional insulin treatment. Continuous subcutaneous and intramuscular infusions of insulin also failed to control her metabolic instability. Use of a continuous intravenous infusion, however, whereby a portable, variable-rate, battery-operated syringe pump delivered insulin through a subcutaneously tunnelled central venous catheter, resulted in good control. When she was receiving hourly intramuscular insulin injections (a mean of 778 IU daily) mean blood glucose concentrations had been 22.1 +/- 1.4 mmol/l (398 +/- 25 mg/100 microliters). After she had received the intravenous infusion for one month as an outpatient mean blood glucose concentration was 8.2 +/- 0.46 mmol/l (148 +/- 8 mg/100 microliters) and only 80 IU insulin daily was required. Follow-up after over five months of use showed that few complications had occurred. The system is simple to use and safe, and the diabetes had been stabilised such that she could enjoy a near-normal life style.

Acid glycohydrolase in Chinese hamster with spontaneous diabetes. VII. The lack of short-term glucose-effect in cultured kidney cells

An epithelial cell line, designated CHK-ACE, was established from the kidney of a spontaneously diabetic Chinese hamster from the highly inbred AC line. CHK-ACE was separated into two sublines, CHK-ACE-100 and CHK-ACE-400, by successive passages in 100 and 400 mg/dl glucose respectively. Extra- and intracellular activities of N-acetyl-beta-D-glucosaminidase and beta-D-galactosidase were measured in these cultures after exposure to varying concentrations of glucose (100, 200, 300 and 400 mg/dl) for one passage and 10% heated fetal calf serum for 6.5 h before enzyme measurements were taken; no apparent dependence on medium-glucose concentration was found. In serum-free medium, the time-dependent release of both N-acetyl-beta-D-glucosaminidase and beta-D-galactosidase was sustained for up to 24 h; no significant difference in their activities was found between CHK-ACE-100 cultures grown in 100 and 400 mg/dl glucose for one passage.

Relevance of colour vision and diabetic retinopathy to self-monitoring of blood glucose

A study was performed to determine the effect of colour vision defects and diabetic retinopathy on diabetic patients' ability to use a visual method of measuring their own blood glucose concentrations. Forty-eight diabetics whose colour vision and retinal status was assessed by an ophthalmologist carried out 311 blood glucose estimations using oxidase-peroxidase test strips which were then compared with laboratory values. There was a trend towards poor performance with advancing age but neither colour vision nor diabetic retinopathy had a significant effect on patients' ability to use this visual method of estimating blood glucose concentrations. The vast majority of diabetics who will benefit from being able to monitor their own blood glucose control should have no difficulty in using a visual method of testing, even if they do have defects of colour vision.