Search

For people with insulin-dependent diabetes mellitus (IDDM) renal disease represents a life-threatening and costly complication. The EURODIAB IDDM Complications Study, a cross-sectional, clinic-based study, was designed to determine the prevalence of renal complications and putative risk factors in stratified samples of European individuals with IDDM. The present study examined the relationship between dietary protein intake and urinary albumin excretion rate (AER). Food intake was assessed centrally by a standardized 3-day dietary record. Urinary AER was determined in a central laboratory from a timed 24-h urine collection. Complete data were available from 2696 persons with IDDM from 30 centres in 16 European countries. In individuals who reported protein consumption less than 20 % of total food energy intake, mean AER was below 20 μg/min. In those in whom protein intake constituted more than 20 %, mean AER increased, a trend particularly pronounced in individuals with hypertension and/or poor metabolic control. Trends reached statistical significance for intakes of total protein (% of energy, p= 0.01) and animal protein (% of energy, p= 0.02), while no association was seen for vegetable protein (p= 0.83). These findings support the current recommendation for people with diabetes not to exceed a protein intake of 20 % of total energy. Monitoring and adjustment of dietary protein appears particularly desirable for individuals with AER exceeding 20 μg/min (approximately 30 mg/24 h), especially when arterial pressure is raised and/or diabetic control is poor. [Diabetologia (1997) 40: 1219–1226]For people with insulin-dependent diabetes mellitus (IDDM) renal disease represents a life-threatening and costly complication. The EURODIAB IDDM Complications Study, a cross-sectional, clinic-based study, was designed to determine the prevalence of renal complications and putative risk factors in stratified samples of European individuals with IDDM. The present study examined the relationship between dietary protein intake and urinary albumin excretion rate (AER). Food intake was assessed centrally by a standardized 3-day dietary record. Urinary AER was determined in a central laboratory from a timed 24-h urine collection. Complete data were available from 2696 persons with IDDM from 30 centres in 16 European countries. In individuals who reported protein consumption less than 20 % of total food energy intake, mean AER was below 20 μg/min. In those in whom protein intake constituted more than 20 %, mean AER increased, a trend particularly pronounced in individuals with hypertension and/or poor metabolic control. Trends reached statistical significance for intakes of total protein (% of energy, p= 0.01) and animal protein (% of energy, p= 0.02), while no association was seen for vegetable protein (p= 0.83). These findings support the current recommendation for people with diabetes not to exceed a protein intake of 20 % of total energy. Monitoring and adjustment of dietary protein appears particularly desirable for individuals with AER exceeding 20 μg/min (approximately 30 mg/24 h), especially when arterial pressure is raised and/or diabetic control is poor. [Diabetologia (1997) 40: 1219–1226]

We report on the incidence of new macrovascular disease among the 497 members of the London Cohort of the WHO Multinational Study of Vascular Disease in Diabetics (aged 35–54 years at recruitment) over a mean 8.33 year follow-up period. Overall at the end of the follow-up period the prevalence of macrovascular disease in the cohort was 45%; 43% of the subjects showed evidence of ischaemic heart disease, 4.5% of cerebrovascular disease and 4.2% of peripheral vascular disease. The incidence rates for new disease in those subjects who were free at baseline expressed per 1000 patient years of follow-up were: ischaemic ECG abnormality 23.6 (patients with insulin-dependent diabetes 19.8, patients with non-insulin-dependent diabetes 28.1), myocardial infarction 17.6 (patients with insulin-dependent diabetes 16.5, patients with non-insulin-dependent diabetes 18.8), all ichaemic heart disease 31.7 (patients with insulin-dependent diabetes 30.3, patients with non-insulin-dependent diabetes 33.4), cerebrovascular disease 5.9 and peripheral vascular disease 5.2. Incidence rates were generally similar among men and women except for myocardial infarction in patients with non-insulin-dependent diabetes where men had a significantly higher incidence rate. Macrovascular disease is a major problem in patients with diabetes and in this age group is mainly manifested as ischaemic heart disease.

We have examined the relationship between baseline variables and the incidence of new macrovascular complications amongst the 497 members of the London cohort of the WHO Multinational Study of Vascular Disease in Diabetics over a mean 8.33-year follow-up. In univariate logistic regression analysis the incidence of new ischaemic electrocardiographic abnormality was significantly associated with systolic and diastolic blood pressure, diabetes duration and hypertension in patients with insulin-dependent diabetes, and with smoking in patients with non-insulin-dependent diabetes. New myocardial infarction was associated with systolic blood pressure, plasma cholesterol, proteinuria and smoking in patients with non-insulin-dependent diabetes; there were no significant associations among patients with insulin-dependent diabetes. All new ischaemic heart disease was associated with hypertension in patients with insulin-dependent diabetes, and plasma cholesterol and smoking in patients with non-insulin-dependent diabetes. New cerebrovascular disease was associated with systolic and diastolic blood pressure, ECG abnormality and hypertension. New peripheral vascular disease was associated with smoking. Multivariate analysis showed the following significant associations 1) in patients with insulin-dependent diabetes: ECG abnormality; hypertension, myocardial infarction; smoking, ischaemic heart disease; hypertension, diabetes duration and smoking, 2) in patients with non-insulin-dependent diabetes: ECG abnormality; smoking, myocardial infarction; serum cholesterol, proteinuria and smoking, ischaemic heart disease; smoking. For new cerebrovascular disease, proteinuria and ECG abnormality were significant predictors in multivariate analysis. Patients with diabetes share many of the established risk factors for non-diabetic subjects, in addition proteinuria may be of significance in the prediction of macrovascular disease in diabetes.

Glomerular filtration rate, renal plasma flow and urinary albumin excretion rate were measured during insulin-induced euglycaemia in 12 male Type 1 (insulin-dependent) diabetic patients after a 3-week period of low protein diet (45 g/day) or a similar period on unchanged conventional diet (103 g/day). No changes in glycaemic control, indicated by home blood glucose profiles and serum fractosamine concentration, or in arterial pressure, were noted on either diet. On low protein diet, glomerular filtration rate was lower (p<0.001) in all patients, but there was no difference in renal plasma flow between low protein diet and normal protein diet; filtration fraction fell significantly on low protein diet (p<0.001). Fractional clearance of albumin was also lower (p<0.05) on low protein diet. This study suggests that reduction of dietary protein induces, independently of changes in plasma glucose and arterial pressure, modifications in glomeralar filtration rate, filtration fraction and fractional clearance of albumin, which may be associated with a beneficial effect on the evolution of diabetic renal disease.

Summary: To define the prevalence of large vessel disease in Ethiopian diabetic patients, the protocol of the World Health Organisation Multinational Study of Vascular disease in Diabetics was used in the Diabetic Clinic of Yekatit 12 Hospital, Addis Ababa: 221 of the possible 261 patients aged 35 to 54 years were examined during 6 months. One hundred seven were diagnosed diabetic 1 to 6 years before study, 74, 7 to 13 years and 40, 14 years or more before the study. Forty-two percent were taking insulin; 18% had retinopathy, 7% heavy albuminuria. Body mass index (BMI) of less than 18 kg/m2 was found in 13.6%; 6.4% of men had BMI more than 27 and 50% of women more than 25. Only 30 patients had ever smoked cigarettes. The plasma cholesterol was less than 6.72 mmol/l in 90% of the 221 patients. Vascular disease led to the diagnosis of diabetes in 3 patients. At study, 19.9% were hypertensive but only 5% at the time of diagnosis. Only 1 patient had had ischaemic gangrene, 1 a stroke, 4 intermittent claudication, 4 angina pectoris and 1 a myocardial infarction. Electrocardiograms, centrally Minnesota-coded in London, were interpreted as Coronary Disease Probable in only 6 patients, and Coronary Disease Possible in 25; the other 190 tracings were normal. It is concluded that macrovascular disease is uncommon in middle-aged Ethiopian diabetic patients in Addis Ababa.

Local changes in blood flow at the subcutaneous injection site of the proteinase inhibitor aprotinin and its diluent were measured by photoelectric plethysmography. Aprotinin, but not its diluent, caused local hyperaemia in five normal subjects and in five stable and five brittle insulin-dependent diabetic patients, local blood flow increasing by 80%–180%. The duration of the hyperaemic response was shorter in the brittle diabetic patients than in the other two groups, but there was wide individual variation. Aprotinin is known to enhance subcutaneous insulin absorption in normal subjects and in some brittle diabetic patients. The basis for this might be through increasing blood flow near the injection site rather than by inhibition of insulin breakdown.

In a multinational study, fasting plasma glucose values in 3583 diabetic patients, aged 34–56 years, were related to the characteristics of these subjects and to the presence and severity of microangiopathy as ascertained by standardised methods. The patients were from nine different populations and ranged in number from 193 to 686 per population (London, Warsaw, Berlin (FRG), New Delhi, Tokyo, Havana, Oklahoma Indians, Arizona Pima Indians, and a national sample in Switzerland). In the total group, mean fasting plasma glucose was 8.1 mmol/l for those on diet alone, 9.7 mmol/l for those on oral agents, and 12.7 mmol/l for insulin-treated patients, of whom 25% had values exceeding 16.5 mmol/l. Since many variables were measured in each patient, it was possible to take into account many confounding factors in evaluating the relationship of plasma glucose levels to retinopathy and nephropathy.

To assess the rate of metabolic deterioration and potential risks of failure of continuous subcutaneous insulin infusion during basal insulin delivery, we deliberately stopped infusion in nine insulin dependent diabetics. Plasma glucose, blood 3-hydroxybutyrate and plasma free insulin were measured for 9 h whilst the patients remained supine and fasting. Mean plasma glucose remained unchanged at normal fasting levels for the first hour, then rose to plateau at about 10 mmol/l until the end of the experiment. The final plateau level of glucose varied from patient to patient; two C-peptide secreting diabetics plateaued at low glucose levels. In contrast, blood 3-hydroxybutyrate rose progressively, without plateauing. Plasma free insulin concentrations fell during the withdrawal period and there was a highly significant negative correlation between free insulin and 3-hydroxybutyrate. No patient was more than mildly unwell after 9 h of insulin deprivation. We conclude that under these experimental conditions there is glycaemic autoregulation and that ketones may sometimes be a more appropriate monitor of insulin deficiency or loss of diabetic control than is glucose. Accidental failure of continuous subcutaneous insulin infusion and interruption of basal delivery in resting and fasting diabetics will probably not cause dangerous metabolic or clinical deterioration.

In a 10-year prospective study of 241 people with ‘borderline diabetes” (impaired glucose tolerance) identified by screening of the Bedford adult population, 36 (15%) worsened to diabetes and 128 (53%) substantially improved their glucose tolerance. The major predictor of worsening to diabetes was the level of blood glucose at baseline. This was statistically significant (p< 0.05), independent of other factors, both for deterioration in the first and in the second five years of observation. Body mass index, a measure of adiposity, did not predict worsening to diabetes during the first five years, but was an independent and significant predictor of worsening during the second five years (p< 0.05). The apparent effect of adiposity was complex, for it was also significantly related to improvement in glucose tolerance during the 10-year follow-up. Persons with impaired glucose tolerance are a heterogeneous group and with present knowledge the ability to predict metabolic deterioration is limited.

Mortality rates from coronary heart disease and from all causes have been ascertained over ten years in three groups of people participating in the Bedford Survey — newly-diagnosed diabetics, borderline diabetics and control subjects with normal glucose tolerance. Age corrected mortality rates, from all causes and coronary heart disease, were highest in the diabetics and intermediate in the borderline diabetics and in both groups were similar in men and women. When statistical allowance was made for baseline differences in age, blood pressure and obesity, female borderline diabetics still had a significantly increased risk over their controls of death from ‘all causes’. Much of the difference appeared to be due to a relative excess of deaths due to coronary heart disease. It is concluded that borderline diabetes (or impaired glucose tolerance) is associated with a relatively greater increase in mortality risk in women than men. During the 10-year follow-up of the Bedford borderline diabetics, coronary heart disease morbidity and mortality rates were similar in men and women. Age at entry to the study was the major independent and significant predictor of mortality from all causes. The level of systolic blood pressure and current cigarette smoking at baseline were statistically significant predictors only of mortality due to coronary heart disease.

The urinary excretion of albumin was measured in insulin-dependent diabetics under ordinary conditions of life and in response to exercise. Possible mechanisms of exercise induced albuminuria in diabetics were also investigated. Under ordinary conditions of life the insulin-treated diabetics, as a group, had a higher mean urinary albumin excretion than normal controls; however, half of the diabetics had albumin excretion rates within the control range. A given exercise load (600 kpm/min for 20 min) produced an exaggerated albumin excretion in diabetics, particularly evident in the post-exercise period. The elevated urinary albumin excretion was due to an increased transglomerular passage of albumin, not to reduced tubular reabsorption. The increase was not associated with differences in blood pressure or urine flow between controls and diabetics. This exercise test has proved to be a suitable provocation test to unmask abnormalities in the glomerular handling of albumin that might not be recognisable at rest.

Oral glucose tolerance tests were performed in 12 young men in the Antarctic. Tests were done in the morning and afternoon at three monthly intervals (March, June, September, December). The characteristic diurnal variation in glucose tolerance persisted throughout the year, but was greater in the warmer months (March and December). There were significant seasonal differences in glucose tolerance; blood glucose values were lowest, both morning and afternoon, in December (midsummer). In one pair of tests performed during a reversal of normal sleep/activity pattern, the direction of the normal diurnal variation of glucose tolerance was also reversed.

Six insulin-dependent diabetics were studied on their conventional insulin treatment and during continuous, dual-rate, subcutaneous insulin infusion for periods of up to 4 days. Diabetic control, as assessed by mean plasma glucose, range of plasma glucose values, M-value or range of M-values was improved significantly in 5 patients (mean ± SD plasma glucose concentration on final infusion day 6.9±1.3 mmol/l, versus 11.3±3.2 mmol/l on conventional treatment). Once a suitable insulin dose was established blood glucose control could be maintained by continuous subcutaneous insulin infusion using the same daily infusion rate without frequent adjustment. In some cases this was less than the daily dose on the conventional treatment. However, glycaemic control in one “brittle” diabetic, with unpredictable swings in blood glucose on her normal regimen, was not improved by continuous subcutaneous insulin infusion. During the period tested there was no sepsis at the cannula implantation site and patients did not find the system uncomfortable or unduly inconvenient.

Two hundred and four men with impaired glucose tolerance (borderline diabetes) discovered in a screening examination have been observed for five years and repeated tests of glucose tolerance performed. By pre-determined criteria 27 men ‘worsened to diabetes’ and this metabolic deterioration was not significantly influenced by treatment with carbohydrate restriction with or without a daily dose of 50 mg phenformin. Of the baseline variables measured prior to treatment allocation only the blood glucose values were significantly predictive of ultimate worsening to diabetes.

Potential risk factors have been examined for association with mortality over a 10–12 year follow-up of the patients of the London Cohort of the WHO Multinational Study of Vascular Disease in Diabetics (aged 35–54 year in at entry to the study). Proteinuria has the strongest association with all-cause mortality in univariate analysis being significant in patients of both sexes with Type 2 (non-insulin-dependent) diabetes mellitus and in women with Type 1 (insulin-dependent) diabetes mellitus; both systolic blood pressure (men) and hypertension (both sexes) (as a categorical variable) are significant in Type 1 diabetes. Hypertension is also significantly associated with all-cause mortality in multivariate analysis in both sexes with Type 1 diabetes as proteinuria is in women with Type 2 diabetes. There is an unexpected negative association between plasma creatinine and all-cause mortality in men with Type 2 diabetes. Systolic blood pressure and hypertension are also significantly linked with cardiovascular mortality in Type 1 diabetes, hypertension having an estimated relative risk of 18.6 in multivariate analysis. Serum cholesterol and proteinuria showed the strongest associations with cardiovascular mortality in Type 2 diabetes. Proteinuria is associated with non-cardiovascular mortality in both types of diabetes in univariate but not multivariate analysis. In multivariate analysis hypertension (Type 1 diabetes) and diabetes duration (Type 2 diabetes) are associated with non-cardiovascular mortality. Hypertension and proteinuria have the most consistent associations with mortality in the different analyses with the effect of hypertension appearing stronger in Type 1 diabetes and proteinuria in Type 2 diabetes. Some other proven risk factors in non-diabetic populations had inconstant or absent associations in this group: other, as yet undefined, factors may be important in diabetes.

The 497 members of the London Cohort of the WHO Multinational Study of Vascular Disease in Diabetics have been followed for mortality from 1975 to 1987. During this period 92 patients died. The most common cause of death was myocardial infarction: 36 (39.1%) deaths, heart disease was responsible for 51.1% of deaths and all cardiovascular disease for 55.4%. Neoplastic disease accounted for 25% of the deaths and diabetic nephropathy for 5.4%. Age-standardised mortality rates were higher in men than in women in both Type 1 (insulin-dependent) diabetes and Type 2 (non-insulin-dependent) diabetes. Standardised mortality ratios for the first and second five year follow-up periods were higher for men than for women in Type 2 diabetes but were higher for women than men in Type 1. The results suggest that the female survival advantage seen in the general population may persist in Type 2 but not in Type 1 diabetes.

Cases of malnutrition-related diabetes mellitus conforming to the description of the protein deficient pancreatic diabetes type in Ethiopian patients were compared with Type 1 (insulin-dependent) and Type 2 (non-insulin-dependent) diabetic. Fourteen of 39 malnutriton-related diabetes mellitus patients had fat malabsorption compared with only two of ten Type 1 diabetic patients and one of nine control subjects. Xylose absorption was normal favouring a pancreatic cause for the malabsorption. Plasma C-peptide during oral glucose tolerance test was significantly lower than that in Type 2 diabetic patients and normal control subjects (p<0.01 to 0.001) and was also consistently but not significantly higher than in Type 1 diabetic patients. Glucagon secretion patterns were similar in malnutriton-related and Type 1 diabetic patients. Of 23 new malnutrition-related diabetic patients treated with glibenclamide after nutritional rehabilitation and insulin treatment, only three responded, 14 were unresponsive but remained ketosis free for over eight days while another six developed ketoacidosis or significant ketonuria within two to six days during the trial. Sixteen unselected Type 1 diabetic patients who discontinued their insulin therapy all developed frank ketoacidosis after a mean of 5.5 days. The similarity of the malnutrition-related and Type 1 diabetes mellitus in age of onset, insulin requirement for diabetic control and appearance of ketosis-proneness in some cases, together with the similarity of C-peptide and glucagon secretion patterns suggest that the protein deficient pancreatic diabetes variant of malnutrition-related diabetes mellitus may be Type 1 diabetes mellitus modified by the background of malnutrition rather than an aetiologically separate entity. Community based studies are required to ascertain frequency and types of diabetes mellitus in malnourished populations and the role of genetics and environment in their aetiology.

Associations between overnight urinary albumin excretion rate and prevalent coronary heart disease and its major risk factors were examined in a cross-sectional study of 141 Type 2 (non-insulin-dependent) diabetic patients. Mean albumin excretion rate was higher in men (geometric mean 13.5 μg/min; 95% confidence interval 10.3–17.6) than women (7.5 μg/min; 5.7–9.8, p<0.01). In diabetic men and women mean albumin excretion rate was higher in those with electrocardiographic and/or symptomatic evidence of coronary heart disease than in those without (men, 23.1 μg/ min; 95% confidence interval 13.7–39.0 versus 10.6 μg/min; 7.9–14.2, p<0.01, women, 13.7 μg/min; 8.0–23.5 versus 5.4 μg/min; 4.2–6.8, p<0.01). Multiple logistic regression analysis was used to allow for confounding between variables. In the diabetic group as a whole, raised albumin excretion rate (p<0.001), gender (p<0.05) and systolic blood pressure (p=0.06) entered the “best” model for coronary heart disease prediction. In women, albumin excretion rate alone (p<0.01) and in men albumin excretion rate (p<0.01) and age (p=0.05) entered the “best” models. We conclude that albumin excretion rate is significantly associated with coronary heart disease morbidity after taking into account the confounding effects of raised blood pressure and other cardiovascular risk factors.

Plasma concentrations of glucagon, growth hormone and glucose were measured hourly during an ordinary treatment day in 11 Type 1 (insulin-dependent) diabetic patients with high glomerular filtration rate, 11 Type 1 diabetic patients with normal glomerular filtration rate matched for age, diabetes duration and sex, and five healthy control subjects, simultaneously with the measurement of the glomerular filtration rate using 51Cr EDTA clearance. Plasma glucagon profiles were not statistically distinguishable (p= 0.49) from control values in either group, although they were somewhat lower in the hyperfiltering group. Plasma growth hormone values were higher than control (p=0.07) in both diabetic groups, but were not different between these two groups (p= 0.94). All indices of glycaemic control (glycosylated haemoglobin, urinary glucose excretion, and plasma glucose concentration) were higher in the hyperfiltering group, although no single index reached statistical significance. No correlations between concentrations of these substances and glomerular filtration rate were found. Elevated plasma concentrations of glucagon and growth hormone do not characterise those diabetic patients with high glomerular filtration rate.

Plasma glucose control and arterial pressure were assessed in 28 Type 1 (insulin-dependent) diabetic patients with different degrees of micro-albuminuria. They were divided into two groups according to their urinary albumin excretion rate: a low micro-albuminuria group (n= 16) with albumin excretion ranging between 12.1 and 28.9 μg/min and a high micro-albuminuria group (n= 12) with albumin excretion between 32.4 and 91.3 μg/min. The groups were matched for age, sex and duration of diabetes with the same number of normo-albuminuric (2.0–10.4 μg/min) diabetic control subjects. Both the low and high micro-albuminuria groups had significantly higher glycosylated haemoglobin levels and mean plasma glucose concentrations during a 24-h profile than their respective normo-albuminuric control subjects. A correlation between glycosylated haemoglobin level and urinary albumin excretion rate was found in the whole study group (r= 0.48; p< 0.001). Arterial pressure (both systolic and diastolic) was significantly higher in the high micro-albuminuria group than in either the control group or the low microalbuminuria group. A significant correlation was found between arterial pressure and albumin excretion rate in the whole study population (r= 0.49; p< 0.001) as well as in the pooled micro-albuminuria groups (r= 0.43; p< 0.05). Multiple regression analysis showed that glycosylated haemoglobin and arterial pressure levels were independently correlated with albumin excretion rates. Diabetic patients with micro-albuminuria of any degree have worse glycaemic control than normo-albuminuric patients. Higher levels of arterial pressure, though often sub-hypertensive, are associated with levels of micro-albuminuria predictive of later development of clinical proteinuria. Thus high plasma glucose and high arterial pressure, or both, characterise those diabetic patients at increased risk of nephropathy. These indices of risk are potentially reversible.

The retinal microcirculation of anaesthetised normal cats was studied during hyperglycaemia (15 to 55 mmol/l) induced by intravenous infusion of glucose, using high speed cine fluorescence angiography. Saline (0.150 mmol/l) was infused as a control for the volume effect of glucose solution and equiosmolar mannitol was infused as a control for the osmotic effect. The mean retinal arteriolar inflow rate increased from 34±1 mm/sec to 41±4 mm/sec during glucose infusion, and from 46±1 mm/sec to 56±3 mm/sec during mannitol infusion. The blood pressure similarly increased from 105±5 mmHg to 125±2 mmHg during glucose infusion and from 110 ±7 mmHg to 129±1 mmHg during mannitol infusion. During mannitol infusion the increased inflow was accompanied by a reduction in the arteriolar width so that the volume flow remained unchanged. During glucose infusion this constriction did not occur, resulting in a significantly increased volume of retinal blood flow (9±1 μl/min to 12±1 μl/min).

The circulatory, renal, and hormonal responses to physiological elevation of plasma insulin induced with oral glucose have been studied in seven healthy subjects. Glomerular filtration rate, urinary excretion rates of albumin and β2-microglobulin, haematocrit, pulse rate, blood pressure and plasma catecholamine concentrations have been measured. Physiological hyperinsulinaemia following glucose ingestion was associated with an increase in nor-adrenaline levels and brief tachycardia. No effect was noted on haematocrit, creatinine clearance, urinary albumin excretion, plasma adrenaline concentrations and arterial blood pressure. Urinary β2-microglobulin excretion rates fell shortly after the elevation of plasma insulin, probably indicating enhanced tubular reabsorption. Thus, glucose-induced physiological hyperinsulinaemia does not reduce glomerular filtration rate nor does it increase transglomerular passage of albumin, effects seen after the intravenous bolus injection of 6–8 U of insulin in diabetics.

The inter-relation between hypertriglyceridaemia and glucose intolerance has been studied experimentally in fifteen male subjects by measuring the effect of acute elevation of plasma triglyceride (injection of Intralipid intravenously) upon oral glucose tolerance. The induced hypertriglyceridaemia did not alter the mean blood glucose or plasma insulin response to oral glucose. The associations between plasma triglyceride levels and glucose tolerance observed both in general population studies and in “patient” populations are probably due to a mutual link with a further factor or factors.

The insulin-like activity (ILA) of T.C.A.-ethanol extracts, prepared from the plasma of normal subjects was compared with that of crystalline insulin. Dose-response curves were obtained for the glucose uptake and 14C-glucose incorporation into lipid of the epididymal fat pad and the glucose uptake of the rat hemidiaphragm. For each of these, the dose-response relationship of the ILA of the extract approximated to that of crystalline insulin. The stimulation of 14C-glucose incorporation into lipid by the extracts and by crystalline insulin was suppressed by 10−4M n-ethylmaleimide. Antiserum to ox-insulin from guinea pigs, which completely suppressed the effect of human and bovine crystalline insulin, had no effect upon the ILA of eight extracts and induced a small, but statistically significant reduction in the ILA of four extracts. — Studies were also performed, using gel filtration by sephadex G. 200, on extracts prepared from the plasma of both normal and diabetic individuals, and upon three pooled T.C.A.-ethanol extracts. In each case, the extract showed two peaks of elution of protein, the second being identical with that of 125I-labelled human albumin. The first peak corresponded to an apparent molecular weight of 300000–1000000. Despite the difference in molecular weight, the properties of the two eluates were similar when compared by electrophoresis and by immuno-electrophoresis. Assay of the column eluate showed that both non-suppressible ILA and immunoreactive insulin were present throughout the whole range of elution. — The findings are discussed with reference to the phenomenon of insulin-like activity and of synalbumin antagonism. L'activité insulinique (insulin-like activity: ILA) d'extraits par l'acide trichloracétique (T.C.A.)-éthanol, préparés à partir de plasma de sujets normaux, a été comparée à celle de l'insuline cristalline. Les courbes dose-effet ont été obtenues pour la captation du glucose et l'incorporation de 14C-glucose dans les lipides du tissu adipeux de l'épididyme, et pour la captation du glucose par l'hémidiaphragme du rat. Pour chacun de ces tests la relation dose-effet de l'ILA de l'extrait était voisine de celle de l'insuline cristalline. La stimulation de l'incorporation du 14C-glucose dans les lipides par les extraits et par l'insuline cristalline était supprimée par la n-éthylmaléimide 10−4M. Le sérum de cobaye anti-insuline bovine, qui supprimait complètement l'effet de l'insuline cristalline humaine et bovine, n'a pas eu d'effet sur l'ILA de huit extraits et a produit pour quatre extraits une réduction de l'ILA légère mais statistiquement significative. — Des études ont été aussi réalisées en utilisant la filtration sur gel de Sephadex G 200, sur des extraits préparés à partir de plasma à la fois de sujets normaux et diabétiques et sur trois« pools» d'extraits par le T.C.A.-éthanol. Dans chaque cas, l'extrait a montré deux pics d'élution de protéine, le second étant identique à celui de l'albumine humaine marquée a l'125I. Le premier pic correspondait à un poids moléculaire apparent de 300 000–1000000. En dépit de la différence de poids moléculaire, les propriétés des deux éluats étaient semblables quand on les a comparées par électrophorèse et par immunoélectrophorèse. Un dosage de l'éluat de la colonne a montré que, à la fois, l'ILA non-supprimable et l'insuline immuno-réactive étaient présentes dans toutes les fractions de l'élution. Les résultats sont discutés en se référant au phénomène de l'activité insulinique et de l'antagonisme par synalbumine. Die insulinähnliche Aktivität (ILA) von aus dem Plasma von Normalpersonen gewonnenen Trichloressigsäure-Äthylalkohol-Extrakten und von kristallinem Insulin wurde miteinander verglichen. Es ließen sich Dosis-Wirkungskurven für die Glucoseaufnahme und die Einlagerung von 14C-Glucose in das Fett des epididymalen Fettgewebes und für die Glucoseaufnahme des Hemidiaphragmas der Ratte aufstellen. Für jede dieser Reaktionen war die Beziehung Dosis —Wirkung der ILA der Extrakte annähernd gleich der des kristallinen Insulins. Die Steigerung der 14C-Glucose-Einlagerung in Fett durch die Extrakte und durch kristallines Insulin wurde durch 10−4M n-Äthylmaleimid unterdrückt. Antirinderinsulinserum vom Meerschweinchen, das die Wirkung von menschlichem und kristallinem Rinderinsulin vollständig hemmte, hatte auf die ILA von acht Extrakten keinen Effekt und führte bei 4 Extrakten zu einem kleinen doch statistisch gesicherten Abfall der ILA. Unter Benutzung der Gelfiltration durch Sephadex 200 wurden weitere Versuche mit Extrakten aus dem Plasma normaler und diabetischer Menschen und mit drei „gepoolten” Trichloressigsäure-Alkohol-Extrakten durchgeführt. In allen Fällen zeigte der Extrakt zwei Eiweißelutionsgipfel, wobei der zweite mit dem Gipfel des 125J markierten menschlichen Albumins identisch war. Der erste Gipfel entsprach einem augenscheinlichen Molekulargewicht von 300000 − 1000000. Trotz des Unterschiedes im Molekulargewicht waren die Eigenschaften der beiden Eluate beim Vergleich in der Elektrophorese und Immunelektrophorese ähnlich. Die Insulinbestimmung des Säulen-Eluats zeigte, daß die nichthemmbare ILA und das immunologisch aktive Insulin über den gesamten Elutionsbereich vorhanden waren. — Die Ergebnisse werden in bezug auf das Phänomen der insulinähnlichen Aktivität und des Synalbuminantagonisten besprochen.

Isolated islets of Langerhans, micro-dissected from the duct-ligated pancreas in the rat, survived for at least four hours of incubation, their rate of glucose oxidation continuing linearly during this period. Oxidation of 1-14C-glucose was considerably higher when the glucose concentration in the medium was raised and comparison with other tissue suggested that glucose oxidation of the islets, in particular that by the hexose monophosphate pathway, was specifically stimulated by the higher glucose concentrations. This may well be directly associated with the glucose stimulus to insulin release. Activity of the hexose monophosphate pathway has previously been demonstrated in both fish and mammalian islets and in human islet cell tumours, both by enzyme estimations and by studies with labelled glucose, and the suggestion has been made that activity of the pathway may be linked with insulin synthesis (Field, 1964). Des îlots de Langerhans isolés par microdissection chez le rat, après ligature des canaux pancréatiques, survivent pendant au moins quatre heures d'incubation ≪in vitro≫, leur rythme d'oxydation du glucose se poursuivant d'une manière constante pendant cette période. L'oxydation du 1—14C-glucose était considérablement plus élevée lorsque la concentration en glucose du milieu était augmentée, et la comparaison avec le comportement d'autres tissus a suggéré que l'oxydation du glucose par les îlots, en particulier celle qui s'effectue par la voie de l'hexose monophosphate, était stimulée spécifiquement par les concentrations les plus hautes en glucose. Ce phénomène pourrait bien être directement associé avec le stimulus que le glucose exerce pour libérer l'insuline. L'activité de la voie de l'hexose monophosphate a été antérieurement démontrée à la fois sur les îlots de poisson et de mammifère ainsi que sur les cellules de tumeurs insulaires humaines, à la fois par des estimations enzymatiques et par des études effectuées avec du glucose marqué, et la suggestion a été faite que l'activité de cette voie métabolique pouvait être liée à celle de la synthèse de l'insuline (Field, 1964). Nach Ligatur der Pankreasausführungsgänge bei der Ratte durch Mikrodissektion gewonnene Langerhans'sche Inseln können durch Inkubation in vitro am Leben erhalten werden und bleiben für mindestens 4 Stunden in der Lage, Glukose mit konstanter Geschwindigkeit zu oxydieren. Eine Erhöhung der Glukosekonzentration des Mediums führt zu einer beträchtlich gesteigerten Oxydation der Glukose-1-14C. Diese Stimulierung der Glukoseoxydation durch die Inselzellen scheint selektiv zu sein, wie der Vergleich mit der Stimulation, die man unter den gleichen Bedingungen durch andere Gewebe erhält, annehmen läßt. Besonders die direkte Oxydation des Glukose-6-phosphats scheint gesteigert zu sein. Es ist möglich, da\ dieser Stoffwechseleffekt von einer durch Glukose gesteigerten Insulinsekretion begleitet wird. Das Vorhandensem des Pentosezyklus in den Langerhans'sehen Inseln von Fischen und Säugetieren, sowie in den Zellen von Tumoren mit Insulinaktivität ist bereits nachgewiesen worden. Diese Beobachtungen stützen sich auf enzymatische Messungen und vergleichende Stoffwechseluntersuchungen mit markierter Glukose, und es ist möglich, daß die Aktivität des Pentosephosphatzyklus mit derjenigen der Insulinsynthese verknüpft ist. (Field, 1964)

Suggestions that diabetes of younger- and older-onset are inherited differently have been examined in a family study which compares the first-degree relatives of 735 diabetic patients with those of 514 ‘control’ patients. Verbally reported histories from the propositi indicated an excess prevalence of known diabetes among the siblings of younger-onset diabetics; however, when the ostensibly normal, first-degree relatives were examined a high frequency of unsuspected glucose tolerance test abnormality was found. When the diabetes prevalence in relatives of diabetics was compared with that in relatives of controls (Kratio), a method at present widely used to determine the mode of inheritance, a number of problems arose suggesting that this means of genetic analysis may be misleading in diseases such as diabetes. It is concluded, for reasons which are discussed, that differences in prevalence ratios cannot be accepted as good evidence for different modes of inheritance of younger- and older-onset diabetes in man. La suggestion a été faite que le diabète commençant dans la première moitié de la vie est transmis d'une façon différente du diabète diagnostiqué plus tard.- Nous avons examiné cette hypothèse dans une étude qui compare les membres du premier degré des familles de 735 malades souffrant du diabète avec ceux des 514 sujets de contrôle. Les histoires familiales des malades, rapportées oralement, ont indiqué une prevalence excessive de diabète connu parmi les frères et les soeurs des diabétiques juvéniles. Toutefois, lorsque les membres —supposés normaux — furent examinés, une haute fréquence d'intolérance au glucose non-soupçonnée fut trouvée. Quand la prévalence de la maladie dans les familles des diabétiques fut comparée avec celle des sujets de contrôle (rapportK)— méthode souvent employée actuellement afin de déterminer le mode de transmission du diabète — nous nous sommes trouvés en face de certains problèmes qui sembleraient indiquer que cette méthode d'analyse génétique pourrait mener à certaines erreurs d'interprétation dans les maladies telles que le diabète. — Pour les raisons examinées, nous concluons que des différences dans les rapports de prévalence ne peuvent pas être acceptées comme preuves convaincantes d'un mode de transmission différent du diabète juvénile et du diabète d'apparition plus tardive. Die Hypothese eines unterschiedlichen Vererbungsmodus für den Diabetes mit frühzeitiger Krankheitsmanifestation und den Diabetes mit späterem Krankheitsausbruch wurde auf Grund von Familienuntersuchungen geprüft. Blutsverwandte 1. Grades von 735 Diabetikern wurden mit einer entsprechenden Kontrollgruppe von 514 Personen verglichen. Bei den Blutsverwandten der Patienten mit früher Diabetesmanifestation ist aus den Krankheitsanamnesen und mündlichen Berichten eine größere Diabeteshäufigkeit zu ermitteln. Wenn indessen die scheinbar normalen Verwandten ersten Grades untersucht wurden, fand man eine große Anzahl vorher unbekannter Fälle von Glueosetoleranzstörung. Bei einem Vergleich der Diabeteshäufigkeit unter den Verwandten der Zuckerkranken und den Verwandten der Kontrollfälle (KVergleichszahl) einer Methode, die z. Zt. oft zur Bestimmung des Vererbungsmodus benutzt wird, ergaben sich einige Probleme, die andeuten, daß diese Art Vererbungsanalysen bei Erkrankungen, wie dem Diabetes, irreführend sein können. Aus den Ergebnissen der Untersuchungen wird gefolgert, daß die zahlenmäßigen Unterschiede, die sich bei dieser Methode des Vergleichs ergeben, keinen Beweis für einen unterschiedlichen Vererbungsmodus des früher oder später sich manifestierenden Diabetes darstellen.

The hypothesis that glucagon effects insulin release by causing glycogenolysis within the B cells of the Islets of Langerhans was tested in two ways. In the first, islets were incubated in the presence of14C-glucose and with or without glucagon, and the14CO2production measured. Glucagon failed to elicit a fall in14CO2production, suggesting little dilution of the intra-cellular glucose-6-phosphate pool. In the second, the effect of glucagon was studied on islet glycogen, previously labelled with radioactive glucose. Glycogen radioactivity following chemical isolation was similar when glucagon was absent or present. No effect of 2-deoxy-D-glucose on14CO2production from labelled glucose was found but it was greatly diminished in the presence of D-mannoheptulose. Nous avons examiné de deux façons l'hypothèse quel'action du glucagon sur la libération de l'insuline est attribuée à la glycogénolyse dans les cellules bêta des îlots de Langerhans. — En premier lieu, les îlots furent incubés en présence de14C-glucose avec ou sans glucagon, et la production de14CO2fut mesurée. La présence du glucagon ne produisit aucune réduction dans la production de14CO2, ce qui suggère donc qu'il n'y a pas eu de dilution du “pool” glucose-6-phosphate intracellulaire.-En second lieu, nous avons examiné l'effet du glucagon sur le glycogène des îlots, marqué préalablement au glucose radio-actif. Après l'isolement chimique du glycogène, sa radioactivité fut la même avec ou sans glucagon. Le 2-deoxy-D-glucose n'eut aucun effet sur la production de14CO2à partir du glucose marqué mais cette production fut fortement diminuée par la présence de D-mannoheptulose. Die Hypothese, daß Glucagon über eine gesteigerte Glykogenolyse in den β-Zellen der Langer -hans'schen Inseln auf die Insulinabgabe wirkt, wurde mit zwei verschiedenen Verfahren überprüft. Erstens wurden die Langerhans'schen Inseln in Gegenwart von14C-Glucose mit und ohne Glucagon inkubiert und die14CO2Produktion gemessen. Glucagon senkte die14CO2Bildung nicht, so daß anzunehmen ist, daß nur eine geringe Verdünnung des intracellulären Glucose-6-Phosphat-Pool eintritt. — Zweitens wurde der Einfluß von Glucagon auf das mit radioaktiver Glucose markierte Inselzell-Glykogen untersucht. Dieses Glykogen zeigte nach seiner chemischen Isolierung nach Inkubation mit und ohne Glucagon die gleiche Radioaktivität. Zusatz äquimolecularer Mengen von 2-Desoxy-D-Glucose beeinflußte die14CO2Bildung aus markierter Glucose nicht, diese war jedoch in Gegenwart von D-Mannoheptulose stark herabgesetzt.

Insulin induced hypoglycaemia was enhanced in rats, by the simultaneous administration of disodium EDTA or calcium disodium EDTA but not bmagnesium disodium EDTA. None of these EDTA complexes affected the blood sugar in the absence of insulin.In vitro, both Na and Ca EDTA inhibited the insulin stimulation of glucose uptake by the isolated rat hemidiaphragm, but had no effect upon basal glucose uptake. In contrast, Mg EDTA increased basal glucose uptake with little or no effect upon insulin stimulation. On the isolated epididymal fat pad, both Na and Ca EDTA either did not affect, or slightly reduced, the insulin stimulation of glucose uptake. They sometimes increased the basal glucose uptake. Mg EDTA consistently increased the basal glucose uptake. -It is suggested that thein vivoeffect of Ca and Na EDTA is upon the homoeostatic response to hypoglycaemia rather than upon the action of insulin. L'hypoglycémie provoquée par l'insuline était augmentée chez les rats par l'administration simultanée d'EDTA disodique ou d'EDTA calco-disodique, mais non par l'EDTA magnésio-disodique. Aucun de ces complexes EDTA ne modifiait le glucose sanguin en l'absence d'insuline. —In vitro, l'EDTA de Na et l'EDTA de Ca inhibaient tous les deux la stimulation due à l'insuline, de la captation de glucose par l'hémidiaphragme isolé du rat, mais n'avaient pas d'effet sur la captation basale de glucose. — Par contre, l'EDTA de Mg augmentait la captation basale de glucose avec peu ou pas d'effet sur la stimulation due à l'insuline. Sur le tissu adipeux épididymaire, l'EDTA de Na et l'EDTA de Ca ou bien ne modifiaient pas, ou bien réduisaient légèrement la stimulation par l'insuline de la captation du glucose. Ils augmentaient parfois la captation basale de glucose. L'EDTA de Mg augmentait nettement la captation basale de glucose. — On suggère que l'effetin vivode l'EDTA de Ca et de Na s'exerce sur la réponse homéostasique à l'hypoglycémie plutôt que sur l'action de l'insuline. Bei Ratten wurde die insulininduzierte Hypoglykämie durch gleichzeitige Gabe von Dinatrium-EDTA oder Calcium-Dinatrium-EDTA, nicht jedoch von Magnesium-Dinatrium-EDTA, verstärkt. Ohne Insulin beeinflußte keine dieser Verbindungen den Blutzuckerspiegel. —In vitrohemmten sowohl Na-als auch Ca-EDTA die insulinstimulierte Glucoseaufnahme des isolierten Rattendiaphragma, doch hatten diese Verbindungen keinen Einfluß auf die basale Glucoseaufnahme. Im Gegensatz dazu führte Mg-EDTA zu einer Steigerung der basalen Glucoseaufnahme mit wenig oder fehlender Wirkung auf die insulinstimulierte Glucoseaufnahme. Am isolierten epididymalen Fettgewebe zeigten Na- und Ca-EDTA entweder keinen oder einen leicht hemmenden Einfluß auf die insulinstimulierte Glucoseaufnahme. Manchmal kam es zu einer Steigerung der basalen Glu-coseaufnahme. Übereinstimmend steigerte Mg-EDTA die basale Glucoseaufnahme. — Es wird angenommen, daß derin vivo— Effekt des Ca- und Na-EDTA eher durch Wirkung auf den homöostatischen Regulationsmechanimus bei der Hypoglykämie als durch Beeinflussung der InsulinWirkung zustande kommt.

In a study of 23 matched pairs of Type 1 (insulin-dependent) diabetic patients receiving continuous subcutaneous insulin infusion or conventional insulin injection therapy respectively, there were no significant differences in serum levels of the acute phase proteins, serum amyloid A and C-reactive protein. These results do not support the suggestion that continuous subcutaneous insulin infusion stimulates serum amyloid A production or that it carries a risk of inducing reactive systemic amyloidosis.

A formal evaluation of the Sarstedt capillary tube system for blood glucose sampling was undertaken. Results obtained with the method were found to be highly reproducible (coefficient of variation = 4.7%) and accurate (mean±SD difference between this system and a reference system =-0.14±0.45 mmol/l). A decline in glucose values by 10% occurred when they were stored for 48 h before analysis, and this decline persisted in samples kept at room temperature, but was abolished by storage at 4 °C.