Secretory B-cell activity in insulin dependent maturity-onset diabetic.

In 10 insulin dependent maturity onset diabetics we found elevated basal C-Peptide levels (4.78 +/- 0.5 ng/ml. Normal range 1.1--3.6 ng/ml), which could be suppressed by insulin injection to the same extent as in sulfonylurea treated diabetics could be demonstrated. C-Peptide immunoreactivity in these patients therefore seems to be newly secreted rather than accumulated material. Since adrenalectomized patients could be suppressed in the same way, it is likely, that catecholamines are not the major factor in the mechanism of suppression. Therefore only decrease of bloodsugar levels seems to be accountable for the decrease of C-Petide levels. High C-Petide levels in insulin dependent maturity onset diabetics which cannot be stimulated but suppressed may be explained by a loss of glucoreceptor molecules.     

Efficacy of captopril in postponing nephropathy in normotensive insulin dependent diabetic patients with microalbuminuria.

OBJECTIVE--To assess the effectiveness of angiotensin converting enzyme inhibition in preventing the development of diabetic nephropathy (albuminuria greater than 300 mg/24h). DESIGN--Open randomised controlled study of four years'' duration. SETTING--Outpatient diabetic clinic in tertiary referral centre. PATIENTS--44 normotensive (mean blood pressure 127/78 (SD 12/10) mm Hg) insulin dependent diabetic patients with persistent microalbuminuria (30-300 mg/24h). INTERVENTIONS--The treatment group (n = 21) was initially given captopril (25 mg/24 h). The dose was increased to 100 mg/24 h during the first 16 months and thiazide was added after 30 months. The remaining 23 patients were left untreated. MAIN OUTCOME MEASURES--Albuminuria, kidney function, development of diabetic nephropathy (albuminuria greater than 300 mg/24 h), and arterial blood pressure. RESULTS--Clinical and laboratory variables were comparable at baseline. Urinary excretion of albumin was gradually reduced from 82 (66-106) to 57 (39-85) mg/24 h (geometric mean (95% confidence interval)) in the captopril treated group, whereas an increase from 105(77-153) to 166 (83-323) mg/24 h occurred in the control group (p less than 0.05). Seven of the untreated patients progressed to diabetic nephropathy, whereas none of the captopril treated patients developed clinical overt diabetic nephropathy (p less than 0.05). Systemic blood pressure, glomerular filtration rate, haemoglobin A1c concentration, and urinary excretion of sodium and urea remained practically unchanged in the two groups. CONCLUSIONS--The findings suggest that angiotensin converting enzyme inhibition postpones the development of clinical overt diabetic nephropathy in normotensive insulin dependent diabetic patients with persistent microalbuminuria.     

Serum Lp(a) lipoprotein concentrations in insulin dependent diabetic patients with microalbuminuria.

OBJECTIVE--To compare the serum concentrations of lipoproteins and apolipoproteins in insulin dependent diabetic patients with and without microalbuminuria. DESIGN--Cross sectional study. SETTING--Paediatric and medical outpatient clinic at a university hospital. PATIENTS--76 insulin dependent diabetic patients: 41 with microalbuminuria (20 males, 21 females) and 35 controls without microalbuminuria (18 males, 17 females). The two groups were similar with respect to age, duration of disease, and haemoglobin A1c concentrations before the study. MAIN OUTCOME MEASURES--Serum concentrations of Lp(a) lipoprotein, total cholesterol, high density lipoprotein cholesterol, very low density lipoprotein cholesterol, low density lipoprotein cholesterol, triglycerides, and apolipoproteins A-I, A-II, and B. RESULTS--Median serum Lp(a) lipoprotein concentration was 10.0 mg/100 ml in the microalbuminuric group and 4.9 mg/100 ml in the control group (p = 0.007). 17 (41%) of the microalbuminuric patients and five (14%) of the control patients had Lp(a) lipoprotein values above the upper quartile of a normal population. Median serum triglycerides concentrations in the microalbuminuric and control groups were 1.15 mmol/l and 0.88 mmol/l respectively (p = 0.03). Median very low density lipoprotein cholesterol concentration was 0.52 mmol/l in the microalbuminuric group and 0.40 mmol/l in the control group (p = 0.03). No significant differences in serum concentrations of total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, or apolipoproteins A-I, A-II, and B were found between the groups. CONCLUSIONS--Serum concentrations of Lp(a) lipoprotein are twice as high in insulin dependent diabetic patients with microalbuminuria as in those without microalbuminuria. Increased concentrations of Lp(a) lipoprotein might partly explain the increased morbidity and mortality from cardiovascular disease observed among patients with diabetic nephropathy.     

Long term correction of hyperglycaemia and progression of renal failure in insulin dependent diabetes

The effect of long term correction of hyperglycaemia on the rate of deterioration of renal function was studied in six insulin dependent diabetics with proteinuria due to diabetic nephropathy. After a planned run in observation period of 10 to 24 months patients entered a programme of continuous subcutaneous insulin infusion for up to 24 months. Glycaemic control was promptly and significantly improved and optimal glycaemic values sustained throughout the study. Blood pressure was maintained stable. A control group of six nephropathic diabetics was studied receiving conventional insulin injection treatment but also with blood pressure control over the same period.Despite greatly improved metabolic control in the infusion treated group no significant change in the rate of decline of glomerular filtration rate could be shown, the plasma creatinine concentrations continued to increase, and the fractional clearance of albumin and IgG rose progressively, indicating progression of glomerular damage. The conventionally treated control group behaved similarly. In a single patient receiving the continuous infusion the rate of decline of the glomerular filtration rate slowed considerably, suggesting that the response to strict diabetic control may differ in some patients.These findings suggest that by the time glomerular function has started to fail in diabetic nephropathy the process culminating in end stage renal failure has become self perpetuating and is little influenced by the degree of metabolic control. A new definition of potential clinical diabetic nephropathy is proposed that will permit identification of patients at risk and earlier intervention by glycaemic correction in an attempt to arrest diabetic renal disease.     

Universal precautions to prevent HIV transmission to health care workers: an economic analysis.

The universal precautions recommended by the US Centers for Disease Control (CDC), Atlanta, for the prevention of HIV (human immunodeficiency virus) transmission to health care workers are widely accepted, despite little documentation of their effectiveness and efficiency. We reviewed the evidence on the risk of HIV transmission to hospital workers and the effectiveness of the universal precautions. We also evaluated the costs of implementing the recommendations in a 450-bed acute care teaching hospital in Hamilton, Ont. On the basis of aggregated results from six prospective studies the risk of HIV seroconversion among hospital workers after a needlestick injury involving a patient known to have AIDS (acquired immune deficiency syndrome) is 0.36% (upper 95% confidence limit 0.67%); the risk after skin and mucous membrane exposure to blood or other body fluids of AIDS patients is 0% (upper 95% confidence limit 0.38%). We estimated that 0.038 cases of HIV seroconversion would be prevented annually in the study hospital if the CDC recommendations were followed. The incremental cost of implementing the universal precautions was estimated to be about $315,000 per year, or over $8 million per case of HIV seroconversion prevented. If all HIV-infected workers were assumed to have AIDS within 10 years of infection the of the program would be about $565,000 per life-year saved. When less conservative, more probable assumptions were applied the best estimate of the implementation cost was $128,862,000 per case of HIV seroconversion prevented. The universal precautions implemented in the study hospital were not found to be efficacious or cost-effective. To minimize the already small risk of HIV transmission in hospitals the sources of risk of percutaneous injury should be better defined and the design of percutaneous lines, needles and surgical equipment as well as techniques improved. Preventive measures recommended on the basis of demonstrated efficacy and aimed at routes of exposure that represent true risk are needed.     

Responsiveness of renal glomeruli to adenosine in streptozotocin-induced diabetic rats dependent on hyperglycaemia level.

Glomerular filtration rate (GFR) in response to adenosine precursor, NAD, and glomeruli contractility in response to adenosine were evaluated in streptozotocin-induced diabetic rats with severe (blood glucose 27.8 +/- 1.2 mmol/L) and moderate hyperglycaemia (18.2 +/- 0.9 mmol/L) compared with nondiabetic (ND)-rats. In anaesthetised rats, basal GFR was greater in moderately diabetic rats compared with severely diabetic rats (p < 0.05) and ND-rats (p < 0.02). Intravenous infusion of 5 nmol x min(-1) x kg(-1) NAD reduced GFR and renal plasma flow (RPF) in diabetic rats but had no effect on these parameters in ND-rats. Moreover, NAD-induced reduction of GFR and RPF was greater in rats with severe diabetes (41% and 30%, respectively) than in with moderate diabetes (25% and 26%, respectively). Theophylline (0.2 micromol x min(-1) x kg(-1) ) abolished renal response to NAD. Isolated glomeruli contraction in response to adenosine, assessed by glomerular 3H-inulin space reduction, was lowered in moderately diabetic-group and enhanced in severely diabetic-group. compared with ND-group (p < 0.05). Adenosine A1-receptor antagonist DPCPX inhibited adenosine-induced glomeruli contraction. This differential response of diabetic renal glomeruli to adenosine suggests that impaired glomerular contractility in response to adenosine could be responsible for hyperfiltration in moderate diabets, whereas, the increased adenosine-dependent contractility of glomeruli in severe diabetes may increase the risk of acute renal failure in this condition.     

Risk of severe hypoglycaemia in insulin treated diabetic patients transferred to human insulin: a case control study.

OBJECTIVE--To examine whether transfer from animal insulin to human insulin is associated with an increased risk of severe hypoglycaemia. DESIGN--Matched case-control study of insulin treated diabetic patients admitted to hospital because of hypoglycaemia during 1984-7, the period when human insulin was introduced into treatment. SETTING--Case admissions and control admissions were obtained from eight public hospitals within the Swiss canton of Berne and a second control group comprised members of the Bernese section of the Swiss Diabetes Association. SUBJECTS--94 patients with insulin treated diabetes with a total of 112 admissions for hypoglycaemia during 1984-7 (case admissions), 182 patients with insulin treated diabetes seen in the same hospitals for reasons other than hypoglycaemia with a total of 225 admissions (control admissions), and 86 insulin treated diabetic patients who were members of the Bernese section of the Swiss Diabetes Association. MAIN OUTCOME MEASURES--Type of insulin used at time of admission, glycaemic control as measured by amount of glycated haemoglobin or glucose concentration; severity of hypoglycaemia. RESULTS--Treatment with human insulin at admission was more common in cases than controls (52/112 (46%) admissions v 77/225 (34%); p = 0.003). 116 out of 129 (90%) of admissions taking human insulin had been transferred from animal insulin, mainly because of non-availability of porcine insulins. The ratio of rate of hypoglycaemia in those taking human insulin to the rate in those taking animal insulin was 2.4 (95% confidence interval 1.3 to 4.4). Other risk factors for hypoglycaemia were a history of hypoglycaemic coma (rate ratio of history to no history 3.8, 2.3 to 6.4) and good glycaemic control (rate ratio of good to poor control 3.9, 1.4 to 7.5). With multivariate analysis the increase in rate ratio associated with use of human insulin rose to 3.0 (1.4 to 6.4). Comparison with the diabetes association controls also showed an increased risk associated with use of human insulin (2.2; 1.1 to 4.8). CONCLUSIONS--Transfer of treatment from animal insulin to human insulin was associated with an increased risk of severe hypoglycaemia. Caution should be exercised when transferring diabetic patients to human insulin. Further studies are required to elucidate why this effect occurs.     

Insulin dependent diabetes mellitus accompanied by nephrocalcinosis and renal failure.

Renal failure was found in a five-year-old patient who had been treated with insulin since he was diagnosed as having insulin dependent diabetes mellitus (IDDM) at 3 years of age. Laboratory data showed that his renal failure was caused by a renal tubular dysfunction. The autopsy findings of his pancreas were compatible with those of IDDM. The kidneys were atrophied with an innumerable number of crystals in the proximal tubuli. Staining by Kossa indicated that the crystals contained calcium salt. The calcium content of his kidneys was significantly higher than that of control. The nephrocalcinosis seems to be caused by hypercalciuria associated with IDDM.     

Screening for congenital dislocation of the hip: an economic appraisal.

The direct costs of screening for congenital dislocation of the hip (CDH) are compared with the treatment costs resulting from no screening in a cost-effectiveness analysis in British Columbia. Under certain conditions the costs associated with screening and subsequent conservative treatment for 6 to 15 positive cases of CDH/1000 liveborn infants were considerably lower than the costs of either open or closed reduction of the hip for 1.5 infants with CDH per 1000 infants not screened. When adjustments were made to the assumptions about screening costs, rates with which cases were missed and hospital treatment costs, only the assumptions thought to be overly unfavourable to screening and overly optimistic for no screening brought the costs of no screening within the likely range of costs of screening. Some specific and general implications of the cost-effectiveness of screening for CDH in British Columbia are discussed.     

Effect of insulin therapy on renal changes in spontaneously diabetic Torii rats.

The spontaneously diabetic Torii (SDT) rat has recently been established as an animal model of non-obese type 2 diabetes, in which ocular complications severe occur. However, the function and morphological features of the diabetic renal lesions in SDT rats have not been reported in detail. Therefore, we evaluated changes over time in renal lesions in SDT rats. In addition, SDT rats were treated with insulin to observe whether these renal complications are caused by hyperglycemia. Renal functional parameters and renal lesions were monitored in SDT rats from 8 to 68 weeks of age. Sprague-Dawley (SD) rats of similar age were used as control animals. In the insulin-treated group of SDT rats, insulin pellets were implanted at 24 weeks of age to compare the development of renal lesions. The SDT rats began to develop hyperglycemia at 20 weeks of age. In the histopathological examination of the kidney, glycogen deposition of the renal tubular epithelium and renal tubular dilation were observed from 24 weeks of age in the untreated SDT rats, and the changes in the renal tubules markedly progressed with aging. Moreover, thickening of the glomerular basement membrane was observed from 32 weeks of age. At 50 weeks of age, the glomeruli showed increase of mesangial matrix, with predominantly diffuse lesions showing by 68 weeks of age. The mesangial proliferation gradually progressed. In the SD rats, no renal lesions were present at 50 and 68 weeks of age. SDT rats with insulin treatment remained normoglycemic throughout observation and their renal functional parameters were normal. Glycemic control in SDT rats prevented the development of renal lesions. The features of SDT rats indicate their usefulness as an animal model for investigating diabetic nephropathy.     

Outcomes of pregnancy in insulin dependent diabetic women: results of a five year population cohort study.

OBJECTIVE: To monitor pregnancies in women with pre-existent insulin dependent diabetes for pregnancy loss, congenital malformations, and fetal growth in a geographically defined area of north west England. DESIGN: Population cohort study. SETTING: 10 maternity units in Cheshire, Lancashire, and Merseyside which had no regional guidelines for the management of pregnancy in diabetic women. SUBJECTS: 462 pregnancies in 355 women with insulin dependent diabetes from the 10 centres over five years (1990-4 inclusive). MAIN OUTCOME MEASURES: Numbers and rates of miscarriages, stillbirths, and neonatal and postneonatal deaths; prevalence of congenital malformations; birth weight in relation to gestational age. RESULTS: Among 462 pregnancies, 351 (76%) resulted in a liveborn infant, 78 (17%) aborted spontaneously, nine (2%) resulted in stillbirth, and 24 (5%) were terminated. Of the terminations, nine were for congenital malformation. The stillbirth rate was 25.0/1000 total births (95% confidence interval 8.9 to 41.1) compared with a population rate of 5.0/1000, and infant mortality was 19.9/1000 live births (5.3 to 34.6) compared with 6.8/1000. The prevalence of congenital malformations was 94.0/1000 live births (63.5 to 124.5) compared with 9.7/1000 in the general population. When corrected for gestational age, mean birth weight in the sample was 1.3 standard deviations greater than that of infants of non-diabetic mothers. Infants with congenital malformations weighed less than those without. CONCLUSION: In an unselected population the infants of women with pre-existent insulin dependent diabetes mellitus have a 10-fold greater risk of a congenital malformation and a fivefold greater risk of being stillborn than infants in the general population. Further improvements in the management of pregnancy in diabetic women are needed if target of the St Vincent declaration of 1989 is to be met.