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Biomedical subjects

R R Holman

Publications and source records attributed to R R Holman.

At least 73 records · Page 4Linked to original sources

Rapid restoration of normoglycaemia using intravenous insulin boluses.

The reduction of elevated fasting plasma glucose levels to near normal by repeated intravenous bolus insulin doses, given according to a simple algorithm, has been studied in 17 Type I and 23 Type II, healthy diabetic patients. Using a formula based on the patient's plasma glucose, height and bodyweight with insulin boluses given every 30 min if the plasma glucose remained above 6 mmol/1, plasma glucose levels were reduced to less than 7.5 mmol/1 in 28 (70%) patients by 60 min at which time the mean (+/- 1 SD) plasma glucose level in the Type I diabetic patients had reduced from 18.2 +/- 4.9 to 8.9 +/- 3.5 mmol/1 and in the Type II diabetic patients from 12.3 +/- 3.1 to 5.9 +/- 1.4 mmol/1. None of the patients had symptomatic hypoglycaemia although in one Type I patient the plasma glucose level fell to 2.2 mmol/1. The rate of fall of glucose in the less insulin sensitive patients was not increased by giving more insulin. The regimen allows a reproducible and prompt glycaemic reduction in fasting diabetic patients.

Adult↗

Diabetes mellitus and anaesthesia. A survey of the peri-operative management of the patient with diabetes mellitus.

A variety of methods are currently available for the management of the diabetic patient in the peri-operative period. A questionnaire about current clinical practice was sent to all anaesthetists in the Oxford region. The majority reported that minor surgery in both insulin treated and noninsulin treated diabetic patients warranted no intervention other than avoidance of meals and medication before surgery, and that, for major surgery, a glucose-insulin-potassium infusion should be used. Fifty one out of 71 respondents in the junior staff grades preferred this latter approach for intermediate surgical procedures in insulin treated patients compared with 27 out of 69 of the consultant staff. Most anaesthetists aimed for blood glucose levels of 7-13 mmol/litre in the peri-operative period. The literature is also reviewed.

Anesthesia↗

Optimizing blood glucose control in type 2 diabetes: an approach based on fasting blood glucose measurements.

A structured approach to the management of Type 2 diabetes, aiming to reduce fasting blood glucose levels to near-normal, can provide effective blood glucose control with minimal risk of hypoglycaemia and in a manner acceptable to most patients. When the fasting blood glucose value is maintained in the region 4-6 mmol l-1, protein glycosylation and plasma triglyceride values usually become near-normal and this may help to prevent the development of long-term diabetic complications. We propose a simple management strategy, based on 3-monthly fasting blood glucose determination, which uses not more than two therapeutic agents at any one time. If diet and maximal oral therapy fail to keep fasting blood glucose levels below 6 mmol l-1 then the addition of a basal insulin supplement, e.g. from a once daily injection of ultralente insulin, can restore near-normal fasting blood glucose levels without the need for full insulin replacement therapy. In older patients, where long-term prevention of diabetic complications is not such an immediate priority, less strict blood glucose control may be reasonable, aiming to keep the fasting blood glucose values below 10 mmol l-1 in order to prevent symptoms secondary to glycosuria. Patients can be seen at a monthly general practice morning diabetic mini-clinic or with the aid of a nurse visiting elderly patients at home.

Blood Glucose↗

Islet amyloid, increased A-cells, reduced B-cells and exocrine fibrosis: quantitative changes in the pancreas in type 2 diabetes.

Morphometric analysis of the endocrine and exocrine pancreas was done on immunoperoxidase stained post-mortem tissue from 15 Type 2 diabetic and 10 age-matched control subjects. Thirteen of the 15 Type 2 diabetic patients had islet amyloid deposits (mean, 6.5% islet area) in the corpus (body, tail and anterior part of the head) but not in the caput (the "pancreatic polypeptide rich" part of the head) whereas none was seen in control subjects. In the corpus in diabetic subjects, the pancreatic area density of B-cells was decreased by 24% (p = 0.005) and A-cells increased by 58% (p less than 0.001) compared with control subjects. The mean A/B-cell ratio increased in the corpus from 0.27 in control subjects to 0.57 in Type 2 diabetic patients. Positive immunoreactivity for the amyloid constituent peptide, Diabetes Associated Peptide, was demonstrated in islet amyloid of diabetic subjects and in B-cells of control and diabetic subjects. The increase in A-cells may contribute to the hyperglucagonaemia and hyperglycaemia of Type 2 diabetes. The impaired insulin secretion in Type 2 diabetes may be due to a decrease in B-cells and to disruption of the islet structure by amyloid. Exocrine fat was similar in the control and diabetic subjects with both groups having more in the corpus than the caput. Diabetic subjects had increased exocrine fibrosis in the corpus region (p less than 0.001), but not in the caput. Exocrine fibrosis may be secondary to disordered islet cell function.

Aged↗

Type II diabetes of early onset: a distinct clinical and genetic syndrome?

The inheritance of non-insulin-dependent (type II) diabetes was studied by a continuous infusion of glucose test in all available first degree relatives of 48 diabetic probands of various ages and with differing severity of disease. In an initial study of 38 type II diabetic subjects and their first degree relatives six islet cell antibody negative patients with early onset disease (aged 25-40 at diagnosis) were found to have a particularly high familial prevalence of diabetes or glucose intolerance. Nine of 10 parents available for study either had type II diabetes or were glucose intolerant. A high prevalence of diabetes or glucose intolerance was also found in their siblings (11/16;69%). In a second study of the families of a further 10 young diabetic probands (presenting age 25-40) whose islet cell antibody state was unknown a similar high prevalence of diabetes or glucose intolerance was found among parents of the five islet cell antibody negative probands (8/9; 89%) but not among parents of the five islet cell antibody positive probands (3/8;38%). Islet cell antibody negative diabetics with early onset type II disease may have inherited a diabetogenic gene or genes from both parents. They commonly need insulin to maintain adequate glycaemic control and may develop severe diabetic complications. Early onset type II diabetes may represent a syndrome in which characteristic pedigrees, clinical severity, and absence of islet autoimmunity make it distinct from either type I diabetes, maturity onset diabetes of the young, or late onset type II diabetes.

Adult↗

Quantifying early diabetic retinopathy.

A precise and accurate method of numerically quantifying diabetic retinopathy, on standardised retinal colour photographs, has been developed which allows small changes and trends to be monitored. Colour slides are projected onto a screen and features noted on an acetate sheet which provides a permanent record. Sector analysis showed microaneurysms and haemorrhages to occur most often at the temporal-to-macula area, exudates at the macula and cotton wool spots on the nasal side of the retina. Seventy percent of microaneurysms appeared in the previous year, irrespective of the severity of the retinopathy. In proportion to their usual relative prevalences, after normalisation of distribution, the various features can be combined to provide a single value, the Retinopathy Index. This provides an overall assessment of retinopathy which is suitable for comparing the progress of mild retinopathy in prospective studies.

Aneurysm↗

Glycosylated haemoglobin: comparison of five different methods, including measurement on capillary blood samples.

Glycosylated haemoglobin was measured in venous blood samples and in blood collected in 'Unistep' bottles by isoelectric focusing (IEF), as the reference method, and by electroendosmosis (EEO), the thiobarbituric acid method (TBA), ion-exchange chromatography (IEC) and affinity chromatography (AC). Isoelectric focusing, electroendosmosis and thiobarbituric acid gave similar results. Affinity chromatography gave lower results than isoelectric focusing for normal values but similar results for diabetics. Ion-exchange chromatography gave 24% lower results than isoelectric focusing across the range. Using Unistep collected blood samples and comparing multiple samples from the same patient, electroendosmosis gave the best results (coefficient of variation 4%) and thiobarbituric acid gave slightly less good precision that other methods. Re-use of affinity chromatography columns gave less good precision. Collection of blood samples into a Unistep bottle gave similar results to venous sample results. Storage of venous capillary blood samples in Unistep bottles over 1 week at 21 degrees C gave similar results to immediate assay. Electroendosmosis of blood samples in Unistep bottles gave stable results over 2 weeks. Home collection by a patient of a capillary blood sample into a Unistep bottle allows glycosylated haemoglobin results to be available when seen in the clinic.

Capillaries↗

A practical guide to basal and prandial insulin therapy.

Separating basal and meal-related insulin requirements allows a systematic approach to subcutaneous insulin therapy. Simple guidelines for both the doctor and patient can cater for the spectrum of severity of diabetes. A non-insulin-dependent diabetic who, despite dieting, continues to have moderate fasting hyperglycaemia (6-10 mmol/l) may need only a basal insulin supplement, whereas a totally insulin-dependent diabetic usually needs similar amounts of basal and meal-related insulin. The likely insulin requirements of individual diabetics can be predicted, including the increased amounts required by obese patients. The algorithms have been developed using ultralente to provide the basal insulin requirement, but the principles and doses probably apply to other similarly long-acting insulins or an insulin pump. The insulin doses can be easily altered for varying lifestyles, including night work, religious fasts or long distance aeroplane travel, and for temporary disturbances such as operations or intercurrent infections.

Algorithms↗

Patient-orientated metered capillary blood collection.

A small collector bottle, with a precision-moulded top, allows capillary blood from a finger-prick to be automatically metered into a diluent for subsequent laboratory analysis. This device, which has been successfully used by patients to obtain full blood counts, glycosylated haemoglobin values and blood glucose measurements, may have wide application.

Blood Cell Count↗

Human ultralente insulin.

The greater solubility of human insulin and its possible faster action have led to doubts about whether a sufficiently long acting formulation could be produced to provide a basal supply for diabetics. In a double blind crossover study in 18 diabetics human ultralente insulin was as effective as beef ultralente insulin in controlling basal plasma glucose concentrations (median 5.7 mmol/l (103 mg/100 ml) with human and 6.3 mmol/l (114 mg/100 ml) with beef ultralente insulin respectively). There was no significant difference between human and bovine insulin in the rise in plasma glucose concentration from 0400 to 0700 after an injection the previous morning and no difference between patients receiving an adequate or insufficient dose of human ultralente insulin. Bovine insulin antibody binding was reduced with human insulin (p less than 0.002), which suggests that human insulin is less antigenic than beef insulin. Once daily human ultralente insulin provides a suitable formulation for the basal insulin requirement of diabetics.

Adult↗

Non-uniform distribution of islet amyloid in the pancreas of 'maturity-onset' diabetic patients.

Quantitative morphometry of the pancreases of five 'maturity-onset' diabetic subjects has demonstrated more amyloid in islets of the head, body and tail (where it was found in a mean 29% of the islets occupying a mean 11% islet area) than in islets of the 'pancreatic-polypeptide-rich' lobule of the head (where amyloid was found in a mean of 3% of the islets occupying a mean of 0.7% islet area, both p less than 0.005). The non-uniform amyloid distribution may relate to the hormone content of the islet; the head and tail contained significantly more A, B and D-cells than the pancreatic-polypeptide-rich lobule in both non-diabetic subjects (n = 8) and diabetic patients (n = 5; p less than 0.005). This result is compatible with the previous suggestion that amyloid may be derived from insulin or its precursors.

Aged↗

Prevention of deterioration of renal and sensory-nerve function by more intensive management of insulin-dependent diabetic patients. A two-year randomised prospective study.

74 insulin-dependent diabetic patients with background retinopathy were randomised to continue with usual diabetic care (group U) or to a more intensive programme (group A) using ultralente insulin as basal cover and soluble insulin at mealtimes. Group A attended the clinic more frequently, received closer dietary supervision, and were taught home blood glucose monitoring. Group A had a significantly lower mean glycosylated haemoglobin level during the study, although the mean level also fell in group U towards the end of year 2. Renal and sensory-nerve function were significantly better preserved in group A than in group U. Significant improvements were also seen in low-density-lipoprotein-cholesterol and whole-blood low-shear viscosity. The rate of progression of retinopathy was similar in both groups. It appears that a modest improvement in diabetic control, obtainable in most clinics, has been associated with a reduction in the progression of diabetic tissue damage.

Blood Glucose↗