Oral hypoglycaemic agents: the first thirty years.

A series of 1,333 patients with non-insulin dependent diabetes (NIDDM) treated with oral hypoglycaemic agents (OHAs) between 1956 and 1988 is described. In addition there were 137 patients with insulin dependent diabetes (IDDM). When last on OHAs 51% of the patients with NIDDM were free from symptoms and satisfactorily controlled; 262 patients are known to have died, 223 have had to be changed to insulin and in 41 patients it has been possible to stop OHAs as no longer being needed, usually owing to better dietary compliance. Over the 32 years, 606 patients have been lost to follow-up; this represents 6.3% per year. The rate of development of secondary failure between the first and 20th year of treatment has been about 5% per year. Patients with NIDDM treated with OHAs have been more likely to develop clinically significant neuropathy and peripheral vascular disease; they also had a higher incidence of coronary artery disease than those treated with insulin. OHAs were used in the treatment of 110 patients with IDDM in the early stages of the disease; 44% achieved satisfactory blood glucose control for at least 12 months and a few patients for as long as 10 years. Of those with IDDM treated with OHAs, 44 were under 30 years of age; 55% had well controlled blood glucose levels for more than 12 months (median 2.8 years). Side effects have not been a real problem; 27 patients reported episodes of mild hypoglycaemia, skin rashes occurred in 1% of patients on sulphonylureas, and gastrointestinal symptoms in about 4% of those on biguanide.(ABSTRACT TRUNCATED AT 250 WORDS)

Diabetes in the United Kingdom: a personal series.

A personal series of 6780 patients with diabetes mellitus is reported. Of these 1410 were thought to have insulin-dependent (Type 1) diabetes and 4926 non-insulin-dependent (Type 2) diabetes. Among the former, 128 patients were only diagnosed when in severe ketoacidosis or coma. In 116 patients the diabetes was diagnosed in pregnancy. Chronic alcoholism was an aetiological factor in 75 patients; in 52 it led to the diagnosis being made, and it complicated treatment in 129 additional patients. In the patients with Type 2 diabetes whose treatment was stabilized 23.5% were having insulin injections, 44.5% tablets, and 32.0% diet only. Sight-threatening retinopathy developed in 21.3% of patients with Type 1 and 7.9% of those with Type 2 diabetes. The rate of developing sight-threatening retinopathy was 1.1% of patients per year. Blindness occurred in 0.28% of patients with Type 1 diabetes per year and 0.097% per year in Type 2 diabetes. If the mean survival of patients with retinopathy going blind is 7.5 years, this would mean 7500 people in the UK blind from diabetic retinopathy. There was a striking drop in the annual incidence of blindness after 1970 coinciding with the introduction of specific treatment for diabetic retinopathy. Juvenile cataract developed in 1.7% of patients who developed Type 1 diabetes before 30 years of age. Clinically important diabetic neuropathy developed in 17.4% of patients with Type 1 and 11.6% of those with Type 2 diabetes. The main features were paraesthesiae and numbness (49%), neuropathic ulceration (37%), pain (5%), autonomic symptoms (5%), and amyotrophy (4%). Oculomotor palsies and mononeuropathies were noted. Foot ulceration occurred in 81 patients with Type 1 and 279 of those with Type 2 diabetes. Charcot changes in the feet were noted in 21 patients. Major amputations were needed in 18 patients with Type 1 and 60 with Type 2 diabetes. Proteinuria believed to be due to diabetic nephropathy developed in 12.8% of patients with Type 1 and 4.7% of those with Type 2 diabetes. The prevalence of early renal failure was 4.6% and 1.4%, respectively. Coronary artery disease was noted in 9% of patients with Type 1 diabetes, and was more common in those who developed diabetes after 20 years of age. Myocardial infarction was as common in women as in men. In Type 2 diabetes coronary artery disease gave rise to symptoms in 19.1%, and myocardial infarction was more common in men.(ABSTRACT TRUNCATED AT 400 WORDS)

Subclinical cardiac dysfunction in acromegaly: evidence for a specific disease of heart muscle.

Acromegaly is associated with an increased cardiac morbidity and mortality, but it is not clear whether this is the result of increased incidence of hypertension and coronary heart disease or of a specific disease of heart muscle. Thirty four acromegalic patients were studied by non-invasive techniques. Seven of these patients had raised plasma concentrations of growth hormone at the time of study; three were newly diagnosed and had not received any treatment. Hypertension was present in nine (26%) but only three (9%) had electrocardiographic left ventricular hypertrophy. Echocardiography showed ventricular hypertrophy in 12 (48%) and increased left ventricular mass in 17 (68%) patients. Holter monitoring detected important ventricular arrhythmias in 14 patients. Thallium-201 scanning showed evidence for coronary heart disease in eight patients. Systolic time intervals were normal except when there was coexistent ischaemic heart disease. A comparison between 19 acromegalic patients with no other detectable cause of heart disease and 22 age matched controls showed appreciably abnormal left ventricular diastolic function in the group with acromegaly. The abnormalities shown did not correlate with left ventricular mass or wall thickness. There was no difference in diastolic function between patients with active acromegaly and those with treated acromegaly. Hypertensive acromegalic patients had worse diastolic function than hypertensive controls, suggesting that hypertension may further impair the left ventricular diastolic abnormality in acromegaly. This is the first study to find evidence of subclinical cardiac diastolic dysfunction in acromegaly and it supports the suggestion that there is a specific disease of heart muscle in acromegaly.

Acromegaly.

A personal series of 256 cases of acromegaly/gigantism seen over a 20-year period from 1963 is described. The insidious nature of the condition resulted in delay in diagnosis which was often made by a doctor when seeing the patient for an unrelated problem. Other features which commonly led to the diagnosis being made were headache, change in appearance, carpal tunnel syndrome, amenorrhoea and diabetes. The Hardy system for grading the radiological appearance of the pituitary tumour was used. Widely invasive tumours were not common but tended to occur in patients with younger age of onset and high GH levels. The occurrence of various symptoms and clinical features was noted and the changes resulting from reducing the GH level to normal. The incidence of hypertension, but not of coronary artery disease, is increased and the blood pressure may be reduced following successful treatment. The effects on the upper and lower respiratory tract are reported as well as sleep apnoea and problems associated with anaesthesia. Skin manifestations included sweating, pigmented skin tags, acanthosis nigricans and cutis verticis gyrata. In the skeletal system the incidence of kyphoscoliosis and osteoarthritis especially of the hip is reported: the question of hip replacement is discussed. Diabetes mellitus disappeared in most cases if the acromegaly was cured. In men but not in women the incidence of colloid nodular goitre was increased as was hyperthyroidism in middle-aged women. In two patients a parathyroid adenoma was present: hypercalcaemia was present in five additional patients, but the cause was not determined. The common occurrence of amenorrhoea in the younger women was noted, it was not always associated with hyperprolactinaemia, and often responded to successful treatment of the acromegaly. The association of acromegaly with hirsutism and galactorrhoea is confirmed. The incidence of impotence and loss of libid in the men is discussed: in a proportion of those in whom the acromegaly was cured, potency returned, but in a number depression occurred and what was believed to be psychogenic impotence persisted. Hyperprolactinaemia was found in 49 out of 151 patients with active acromegaly in whom the prolactin level was measured. Previous reports have indicated a doubling of death rates in acromegalics. In this series there were 47 deaths observed compared to 37.2 expected. The increased death rate was in women of all ages and in men under the age of 55, The increased deaths in the women were from cardiovascular and cerebrovascular causes and from breast cancer.(ABSTRACT TRUNCATED AT 400 WORDS)

Peripheral lactate and oxygen metabolism in man: the influence of oral glucose loading.

We investigated the influence of oral glucose loading (100 g) on glucose, lactate, and oxygen metabolism by deep (mainly muscle) and superficial (mainly skin and adipose tissue) forearm tissues. In normal men aged 19 to 32 years (mean +/- SE, 24 +/- 1), basal arterialized venous-deep venous (A-DV) and arterialized venous-superficial venous (A-SV) plasma glucose concentration differences were 4.1 +/- 1.0 (P less than 0.001) and 4.7 +/- 1.0 (P less than 0.005) mg/dL, respectively, but increased markedly following glucose loading. During the first, second, and third hours after glucose ingestion, A-DV differences were 54 +/- 6,43 +/- 3, and 20 +/- 4 mg/dL, respectively, while the corresponding A-SV differences were 39 +/- 4, 17 +/- 2, and 8 +/- 2 mg/dL, respectively. Forearm glucose uptake by deep (FGU-D) and superficial (FGU-S) tissues basally was 0.057 +/- 0.010 and 0.012 +/- 0.002 mg/100 mL forearm/min respectively. From 15 to 180 minutes after glucose loading, mean FGU-D and FGU-S rose to 0.524 +/- 0.083 and 0.056 +/- 0.006 mg/100 mL forearm/min, respectively. Basal A, SV, and DV lactate concentrations were 0.55 +/- 0.04, 0.78 +/- 0.03, and 0.57 +/- 0.04 mmol/L, respectively (A-SV, P less than 0.001; SV-DV, P less than 0.001; A-DV, NS). Lactate production by superficial tissues (0.079 +/- 0.015 mumol/100 mL forearm/min) accounted for 62% of concurrent FGU-S.(ABSTRACT TRUNCATED AT 250 WORDS)

Basal glucose homeostasis with and without fixed concentrations of glucagon and insulin.

The aim of this study was to investigate the extent to which the basal steady state could be maintained with fixed concentrations of glucagon and insulin. To this end, arterial plasma glucose concentrations and peripheral glucose uptake (using the forearm technique) were compared in healthy men (age 19 to 23 years) in the normal postabsorptive state and after suppression of endogenous pancreatic secretion. Two groups (A and B), each consisting of four men, were studied. In group A, the study comprised a control period (I) of 40 minutes followed by a test period (II) of 180 minutes during which normal pancreatic secretion was maintained throughout. In group B, the study comprised a control period (I) of 40 minutes, a stabilization period (II) of 120 minutes, and a test period (III) of 120 minutes. After the control period with normal pancreatic secretion, a new steady state with fixed hormone concentrations was established during the first 90 minutes of period II using simultaneous infusions of somatostatin (250 micrograms/h), insulin (0.15 mU/kg/min) and glucagon, the latter being adjusted to maintain a stable arterial glucose level similar to the preceding control concentration. Thereafter, without further adjustment of the glucagon infusion rate, observations were continued during period III to assess the maintenance of the steady state. In group A, the range of variation in arterial glucose concentrations during periods I and II was 4.0 +/- 0.9 and 6.5 +/- 1.3 mg/dL, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegalic heart disease: influence of treatment of the acromegaly on the heart.

In a series of 256 patients with acromegaly, 10 had evidence of heart disease for which no explanation apart from the acromegaly could be found. Heart disease presented with effort dyspnoea, cardiac failure, palpitation, ECG changes or cardiomegaly. Initial chest radiographs showed cardiac enlargement in seven patients. Electrocardiograms were abnormal in nine patients with repolarisation disorders or intraventricular conduction defects. Rhythm disturbances were found in six. Echocardiograms were performed on six patients; all were abnormal showing left ventricular hypertrophy or impaired function. In five patients radionuclide ventriculography was also performed. Cardiac catheterisation was undertaken on seven patients; all showed either hypertrophy or dilatation of the left ventricle. Coronary arteries were widely dilated in two patients and in another there was dilation of the proximal segment only. In six of the 10 patients, acromegaly was cured by transsphenoidal surgery. This resulted in limited improvement of cardiac function in two patients only. Of the four patients who were not cured, three died and one was lost to the study. Four patients in total died and autopsies were obtained in two: one showed changes suggesting myocarditis and the other diffuse fibrosis. It is concluded that acromegaly may infrequently lead to heart disease, and that if recognised at an early stage progression may, in a proportion of patients, be arrested by successful treatment.

The influence of graded hyperglycemia with and without physiological hyperinsulinemia on forearm glucose uptake and other metabolic responses in man.

We studied the influence of hyperglycemia on glucose homeostasis in man by determining the effect of graded hyperglycemia on peripheral glucose uptake and systemic metabolism in the presence of basal and increased serum insulin concentrations in 10 normal men. This was achieved by the simultaneous application of forearm and clamp techniques (euglycemic and hyperglycemic) during the combined iv infusion of somatostatin, glucagon, and insulin. While mean (+/- SE) basal serum insulin levels (14 +/- 2 microU/ml) were maintained, the elevation of fasting arterial glucose concentrations (90 +/- 1 mg/dl) to 146 +/- 1 and 202 +/- 1 mg/dl (each for 120 min) increased forearm glucose uptake (FGU) only modestly from 0.06 +/- 0.01 to 0.15 +/- 0.02 and then to 0.24 +/- 0.03 mg/100 ml forearm X min, respectively. During physiological hyperinsulinemia (47 +/- 3 microU/ml), the influence of similar graded hyperglycemia on FGU was considerably enhanced. At plasma glucose concentrations of 90 +/- 1, 139 +/- 1, and 206 +/- 1 mg/dl, FGU rose to 0.33 +/- 0.05, 0.59 +/- 0.07, and 0.83 +/- 0.12 mg/100 ml forearm X min, respectively. The glucose infusion rate required to maintain the glucose clamp with basal insulin levels was 1.08 +/- 0.20 and 2.67 +/- 0.39 mg/kg X min at glucose concentrations of 146 +/- 1 and 202 +/- 1 mg/dl, respectively. During physiological hyperinsulinemia, however, the glucose infusion rate required was 4.15 +/- 0.39, 9.45 +/- 1.05, and 12.70 +/- 0.81 mg/kg X min at glucose levels of 90 +/- 1, 139 +/- 1, and 206 +/- 1 mg/dl, respectively. Lactate concentrations rose significantly during hyperglycemia, but the rise in the presence of increased insulin concentrations (from 0.72 +/- 0.06 to 1.31 +/- 0.11 mmol/liter; P less than 0.001) considerably exceeded the increment (from 0.74 +/- 0.05 to 0.92 +/- 0.03 mmol/liter) with basal insulin levels. While both FFA and glycerol concentrations were immediately reduced by euglycemic hyperinsulinemia, the fall in FFA during hyperglycemia in the presence of basal insulin levels preceded the decrease in glycerol concentrations by 45 min. Forearm oxygen consumption did not change throughout the study.(ABSTRACT TRUNCATED AT 400 WORDS)

Relationship among peripheral glucose uptake, oxygen consumption, and glucose turnover in postabsorptive man.

To assess the importance of glucose uptake by muscle in determining total glucose utilization in the basal state, forearm glucose uptake (FGU), reflecting mainly skeletal muscle metabolism, and glucose turnover using [3-3H]glucose were studied simultaneously in 17 postabsorptive normal men. Mean +/- SE glucose disappearance was 2.36 +/- 0.14 mg/kg X min, amounting to 170 +/- 9 mg/min, while FGU was 0.049 +/- 0.009 mg/100 ml forearm X min. When the latter was calculated in terms of skeletal muscle in the body as a whole, muscle glucose utilization was found to be 24.7 +/- 4.5 mg/min, comprising only 13.5 +/- 1.9% of the total glucose disappearance. Forearm oxygen consumption was 6.6 +/- 0.5 mumol/100 ml forearm X min, of which only 26 +/- 5% could be accounted for by concurrent glucose uptake. These results suggest that in the basal state, glucose uptake by skeletal muscle accounts for 1) only a small percentage of total glucose disappearance and 2) only a minor proportion of peripheral oxygen consumption, which may be more dependent on lipid oxidation.

Pancreatic cancer and diabetes mellitus.

In a series of 6,500 patients with diabetes mellitus there were 37 cases of primary carcinoma of the pancreas which significantly exceeded the expected number for the patient years at risk in both males and females (p less than 0.01). There was no evidence that pancreatic cancer was more common in patients with long-standing diabetes. The increased incidence of pancreatic cancer in diabetic patients is probably the result of patients presenting with the symptoms of diabetes as long as four years before the cancer becomes manifest. An underlying pancreatic tumour should be suspected when an elderly diabetic proves difficult to control and loses weight despite adequate treatment.

Peripheral glucose uptake in young men with myocardial infarction.

Forearm glucose uptake (FGU) was studied during 100 g oral glucose tolerance tests (GTT) in nonobese, nondiabetic men who had suffered a myocardial infarction (MI) at or before the age of 40, and the results compared with the response in age-matched normal men. In the MI group the rise in both glucose and insulin concentrations after glucose loading was similar to that in normal subjects, although in the former, peak levels tended to be slightly higher. Concomitant FGU, however, was significantly greater in the MI group than in control subjects in the period 0-90 min and in the test as a whole (0-180 min). The results show that at least in some nondiabetics suffering MI at an early age hyperinsulinism is not a feature and peripheral tissue sensitivity is increased.

Circulating IgG antibody to protamine in patients treated with protamine-insulins.

Sera from patients with different types of protamine-insulin were assayed for IgG antibody to protamine. A high prevalence of circulating antibody was found in patients treated with either bovine isophane insulin (26 out of 28 patients; 26 of whom also had antibodies to insulin), or bovine protamine zinc insulin (27 out of 30 patients; all 30 had antibodies to insulin). In sera from 24 patients treated with highly purified porcine isophane insulin, protamine antibody was detected in nine; circulating insulin-antibody was detected in 12 patients, eight of whom had protamine-antibody; in the 12 patients with no detectable antibody to insulin, antibody to protamine was detected in only one (x2 = 8.7, p less than 0.01). This relationship between insulin and protamine antigenicity is of interest as it suggests that the protamine-insulin complex is itself immunogenic.

Comparison of peripheral glucose uptake after oral glucose loading and a mixed meal.

Forearm glucose uptake (FGU) and other metabolic responses were studied in six normal men for three hours after a 75-g oral glucose load and a mixed meal containing 75 g carbohydrate. After the meal the rise in arterial glucose levels was considerably less than that following the oral glucose load but the overall insulin responses from 0 to 180 minutes were not statistically different. Although the initial rise in FGU was more gradual after the meal, the subsequent elevation was more sustained and, at the termination of the study, exceeded significantly that seen after the oral glucose load. The rise in GIP levels during the first hour was similar after the meal and the oral glucose load, but thereafter concentrations following the oral glucose load fell while those after the meal continued to rise. When the incremental area (delta) is used as the index of response, the results show that while the glucose response (delta G) after the meal (19.1 +/- 5.3 units) was only 26% of that after oral glucose loading (72.7 +/- 7.0 units), the corresponding increase in FGU (delta FGU) reached 62% (55.0 +/- 12.8 units after the meal, 89.2 +/- 20.0 units after the oral glucose load). Thus, the increase in peripheral glucose uptake relative to the glycemic response (delta FGU/delta G) was significantly greater after the meal than following the oral glucose load alone (P less than 0.05). In conclusion, relative to the rise in arterial glucose levels, peripheral glucose uptake is greater after a meal than after glucose loading with an equivalent carbohydrate challenge. Furthermore, the present data support previous studies emphasizing the failure of GIP alone to explain the entero insular axis.

The bioavailability of circulating antibody-bound insulin following insulin withdrawal in Type 1 (insulin-dependent) diabetes.

Insulin withdrawal studies were performed in 12 Type 1 (insulin-dependent) C-peptide negative diabetic patients with low to moderate insulin antibody levels, to assess the biological availability of antibody-bound insulin and its clinical significance. There was a highly significant correlation between the extent to which the free insulin concentration was maintained during the period of insulin withdrawal and both the level of insulin-binding by serum and the total insulin concentration at the start of the study. During insulin withdrawal, the patients who best maintained their circulating free insulin levels showed the smallest increases in blood glucose and 3-hydroxybutyrate concentrations. We conclude that antibody-bound insulin is available for physiological action, and that in those individuals with moderate antibody concentrations it is capable, in the fasting state, of maintaining free insulin levels. In these circumstances insulin antibodies are behaving as simple carrier proteins.

Recovery of hypothalamo-pituitary-adrenal function in asthmatics whose oral steroids have been stopped or reduced.

Hypothalamo-pituitary--adrenal (HPA) function was studied using tetracosactrin and insulin hypoglycemia tests in eleven asthmatic patients who were receiving or had taken oral steroids. The patients had been on prednisone, 5--20 mg/day for 2--17 years. As the dose was reduced they used beclomethasone inhalation, up to 800 micrograms/day. Seven insulin hypoglycemia tests were performed when the patients had been off oral steroids for 15--37 months. Plasma cortisol responses were normal in all seven, three had subnormal responses of ACTH. In five patients serial tetracosactrin and insulin hypoglycaemia tests were performed during reduction of steroid dose. Two patterns of recovery of HPA function were observed. In one, both hypothalamo--pituitary and adrenal function seemed to return simultaneously, in the other normal response to tetracosactrin appeared before that to insulin hypoglycaemia. One patient had normal ACTH and cortisol responses to the stress of a vasovagal attack, but failed to respond to subsequent hypoglycaemia. We conclude that a normal response to tetracosactrin does not indicate recovery of the HPA axis after stopping prolonged oral steroid therapy for asthma, and that patients should continue to carry steroid therapy cards for at least 5 years after such treatment has been discontinued.

Is preoperative localisation of insulinomas necessary?

During the past 20 years 33 patients suspected of harbouring an insulinoma have been investigated. 29 had laparotomy, and tumours were removed from 27.2 of the 29 and 1 other proved not to have an insulinoma, although preoperative imaging had suggested a tumour. Four different localisation procedures were used, and in some patients more than one technique was applied. Selective arteriography of branches of the coeliac axis showed the position of the insulinoma correctly in 9 out of 18 cases, but in all of these the tumour was felt at operation, so that the information provided was unnecessary. Arteriography gave false localisation in 4 patients and missed the tumour completely in 4 but was also negative in 1 patient not harbouring a tumour. Ultrasonic examination provided correct localisation in only 2 out of 11 instances and computer-assisted tomography in 1 out of 8. Insulin estimation in blood obtained at percutaneous transhepatic portal-venous sampling (THPVS) provided correct localisation in 2 out of 8 cases, but in only 1 of these was it needed to guide pancreatic resection. Localisation was spurious in 5 patients, and in 1 there was no evidence of a tumour at all. In 23 patients the surgeon felt and removed the insulinoma at the first operation. In 3 tumour was palpable at a second laparotomy some years later. In only 1 was no tumour felt at operation. The false-positive findings in the THPVS were caused by misinterpretation of data. For a peak of insulin concentration in the portal vein to be meaningful, it should exceed 200 mU/l and to be fully diagnostic it should be greater than 500 mU/l. Present imaging techniques are not precise enough to localise an insulinoma. An experienced surgeon has a very high probability of being able to palpate the tumour at operation, and preliminary localisation is therefore not needed in most cases.