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Biomedical subjects

S Pramming

Publications and source records attributed to S Pramming.

28 records · Page 2Linked to original sources
PubMed1984

Absorption of soluble and isophane semi-synthetic human and porcine insulin in insulin-dependent diabetic subjects.

A double-blind cross-over study of the sc absorption of radiolabelled semi-synthetic human (SHI) and purified porcine (PPI) insulin was made. Absorption of both isophane (n = 10) and soluble insulin (n = 8) was studied. There was no significant difference between the disappearance from the injection site, the plasma free insulin concentrations, or blood glucose levels after sc injection of the isophane preparations. A faster disappearance of the soluble SHI (as judged from T/50 and AUC) was found (both P-values less than 0.01). However, no difference was observed between the plasma insulin concentrations at any time point (P less than 0.05). Blood glucose levels showed no statistical differences between the two soluble preparations. The data indicate minor differences between the pharmacokinetics of SHI and PPI, but these seem of no clinical importance.

Absorption↗
PubMed1984

Insulin pumps--still a research tool?

Long-term near-normal blood glucose regulation is possible with portable insulin pumps, and this treatment is acceptable to patients, but is also expensive. The pharmacokinetic difference between continuous subcutaneous insulin infusion and conventional injection therapy is discussed and can explain the difference between the obtained levels of blood glucose control. One-year near-normal blood glucose regulation cannot prevent the development of proliferative retinopathy in patients with established diabetic background retinopathy. Long-term large-scale prospective clinical trials are needed to evaluate whether strict metabolic control can prevent, delay, arrest, or even reverse microvascular complications. Furthermore, the side effects of the pump treatment need to be clarified before routine use of continuous subcutaneous insulin infusion. While awaiting these studies, the only indication for pump therapy in routine clinic is considerable glycaemic instability which is incompatible with leading a normal life.

Blood Glucose↗
PubMed1983

Pharmacokinetics of continuous subcutaneous insulin infusion.

One of the reasons for the variability of blood glucose regulation in Type 1 (insulin-dependent) diabetic patients is the huge variation in subcutaneous absorption of intermediate-acting insulin. We have investigated the variation in insulin absorption during continuous subcutaneous insulin infusion in eight such patients. The content of insulin in the subcutaneous tissue was measured using 125I-labelled insulin. The concentration of free serum insulin and blood glucose was followed from 1 h before and from 7 h after breakfast on two consecutive days. The amount of insulin absorbed during 24 h differed in all cases by less than 3% from the daily insulin dose given by the pumps. Mean insulin absorption rates and mean free insulin concentration showed peak values 30-90 min after meal bolus injections; this was sufficient to maintain near-normal blood glucose. Mean free serum insulin correlated strongly with disappearance of insulin from the subcutaneous tissue (r = 0.98). From the insulin absorption rates and free insulin concentrations during basal constant insulin infusion, the half-time of serum insulin was calculated as 6 min. Compared with the known large variability in the absorption of intermediate-acting insulin, continuous subcutaneous insulin infusion offers a precise and reproducible way of insulin administration resulting in post-prandial serum insulin peaks sufficient to maintain near-normal blood glucose levels. The half-time of serum insulin during subcutaneous infusion corresponds to values for intravenous infusion given in the literature, indicating that local degradation of insulin in subcutaneous tissue is of minor importance.

Adult↗
PubMed1982

Absorption of isophane (NPH) insulin and its clinical implications.

Absorption of 125I-NPH insulin (125I-isophane insulin) (40 IU/ml) was studied in eight diabetics given 50% and 150% of their normal daily dose of insulin. Insulin absorption correlated with plasma insulin (r = 0.97, p less than 0.001) and blood glucose (r = -0.87, p less than 0.01) concentrations. Absorption was slower at higher doses, so that trebling the insulin dose only doubled the amount absorbed over the first 24 hours. The plasma elimination half time (t12) of insulin was about five minutes. Thus, the disappearance of radiolabelled insulin is a reliable and quantitative index of insulin absorption; subcutaneous degradation, if present, is minimal and constant. Changes in dise of intermediate-acting insulin further increases the large variation in insulin absorption. This implies that minor adjustments of intermediate insulin dosage are probably futile.

Absorption↗
PubMedDate not supplied

A 6-year nationwide cohort study of glycaemic control in young people with type 1 diabetes. Risk markers for the development of retinopathy, nephropathy and neuropathy. Danish Study Group of Diabetes in Childhood.

The study aimed to identify risk markers (present at the start of the study in 1989) for the occurrence and progression of microvascular complications 6 years later (in 1995) in a Danish nationwide cohort of children and adolescents with Type 1 diabetes (average age at entry 13.7 years). Probabilities for the development of elevated albumin excretion rate (AER), retinopathy, and increased vibration perception threshold (VPT) could then be estimated from a stepwise logistic regression model. A total of 339 patients (47% of the original cohort) were studied. Sex, age, diabetes duration, insulin regimen and dose, height, weight, HbA(1c), blood pressure, and AER were recorded. In addition, information on retinopathy, neuropathy (VPT), and anti-hypertensive treatment was obtained at the end of the study. HbA(1c) (normal range 4.3-5.8, mean 5.3%) and AER (upper normal limit <20 microg min(-1)) in two, timed overnight urine collections were analysed centrally. Eye examination was performed by two-field fundus photography. Determination of VPT was assessed by biothesiometry. Increased AER (> or =20 microg min(-1)) was found in 12.8% of the patients in 1995, and risk markers for this were increased AER and high HbA(1c), in 1989 (both p<0.001). Retinopathy was present in 57.8% of patients in 1995, for which the risk markers were long duration of diabetes (p<0.0001), age (p<0.01), and high HbA(1c) (p<0.0001) in 1989. Elevated VPT (>6.5 V) was found in 62.5% of patients in 1995, for which the risk markers were male sex (p<0.05), age (p<0.0001), and increased AER (p<0.05) in 1989. This study confirms that hyperglycaemia plays a major role for the development of microvascular complications in kidneys and eyes, and emphasises the need for optimal glycaemic control in children and adolescents with Type 1 diabetes.

Adolescent↗
PubMedDate not supplied

Insulin pharmacokinetics.

Where adjustments of diet, physical activity, and dosage of insulin are well known to diabetologists and diabetic patients, present-day knowledge of factors of importance to the pharmacokinetics of insulin is frequently ignored. The pharmacokinetics of insulin comprise the absorption process, the distribution including binding to circulating insulin antibodies, if present, and to insulin receptors, and its ultimate degradation and excretion. The distribution and metabolism of absorbed insulin follow that of endogenous insulin. The distribution and metabolism cannot be actively changed, except in the case of circulating insulin antibodies, which in rare cases also may cause insulin resistance. The use of insulin preparation of low immunogeneity will avoid or reduce this course of variation in action. The absorption process, the detailed mechanisms of which are still unknown, is influenced by many variables where some can be controlled, thereby reducing the intrapatient variability in insulin absorption, which may reach 35%, causing a corresponding metabolic lability. Besides the known differences in timing among different preparations, the size of dose, the injected volume, and the insulin concentration are determinants of absorption role. Fortuitous injection technique contributes to variance, as do changes in blood flow of the injected tissue. This may be induced by changes in ambient temperature, exercise of injected limb, or local massage. Regional differences are also due to differences in blood flow. Serum insulin peaks may peak up to 1 h after injection of soluble insulin into the thigh versus into the abdominal wall. Local degradation of insulin seems of less importance but may, in rare cases, be the cause of high insulin "requirements." Available evidence is reviewed and the importance of implementing the consequences in the daily care of the insulin-treated patient is emphasized.

Absorption↗