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Biomedical subjects

U Adamson

Publications and source records attributed to U Adamson.

At least 73 records · Page 4Linked to original sources
PubMed1987

Insulin resistance following nocturnal hypoglycaemia in insulin-dependent diabetes mellitus.

Glucose metabolism was studied by a somatostatin-insulin-glucose infusion test (SIGIT) for 8 h in 7 male patients with insulin-dependent diabetes mellitus. They were investigated on two occasions in random order, with and without preceding hypoglycaemia induced between 3.00 and 4.00 h. SIGIT was started at 7.00 h when blood glucose was restored to normal and the counterregulatory hormones had returned to basal values. As expected, hypoglycaemia evoked an enhancement of the plasma levels of GH (43.7 +/- 10.1 vs 4.4 +/- 1.8 micrograms/l), cortisol (690 +/- 59 vs 140 +/- 32 nmol/l), glucagon (225 +/- 35 vs 143 +/- 25 ng/l), and epinephrine (3.80 +/- 1.00 vs 0.10 +/- 0.03 nmol/l). During the SIGIT, the levels of circulating free insulin and counterregulatory hormones were similar in the two tests notwithstanding that excessive hyperglycaemia appeared when SIGIT was preceded by hypoglycaemia. The present study thus demonstrates that nocturnal hypoglycaemia induces insulin resistance in insulin-dependent diabetic patients not deprived of insulin.

Adult↗
PubMed1987

Primary aldosteronism. A follow-up study of 28 cases of surgically treated aldosterone-producing adenomas.

A follow-up examination was performed one month to 20 years after adrenalectomy in 28 cases with surgically treated primary aldosteronism due to adrenal adenoma. The mean age at diagnosis was 45, and the mean duration of hypertension seven years. Severe hypertension with a diastolic blood pressure of 130 mmHg or more was observed in 35%. Postoperatively cerebrovascular catastrophe developed in two cases, both of which belonged to the group of patients with severe hypertension. Normalization of blood pressure was observed in 70% and in the remaining subjects the blood pressure was lower than at diagnosis. The blood pressure response to adrenalectomy appeared unpredictable in view of such parameters as the initial blood pressure, age at diagnosis, and duration of the hypertensive state. Toxicosis during pregnancy and metrorrhagia was observed with unexpectedly high frequency in this study population. Low ambulatory plasma renin activity was recorded at the follow-up in 15 out of 18 subjects studied in the absence of evidence of hyperaldosteronism.

Adenoma↗
PubMed1987

Some demographic and therapeutic features of diabetes mellitus in Kuwait.

A survey of all consecutive visits to all diabetic clinics in Kuwait over a period of 4 months yielded 1,266 male and 1,838 female Kuwaiti patients. Their age structure analysis revealed percent frequencies of 1.25, 15.5, 57.8 and 25.3 for the age groups under 19, 20-39, 40-59 and over 60 years respectively. The overall female:male ratio was 1.42. The body mass index peaked in the age groups 30-39 (mean +/- SD = 31.3 +/- 7.1 for women and 29.4 +/- 6.4 for men) and was consistently higher in women than in men for all age groups. Diabetic women over 30 years of age received insulin therapy more often than men. Home urine testing was practised by only 25% of those under 30 years of age and 12% of those 30 years and over. The study showed that the majority of Kuwaiti patients were relatively young and that the women were affected more often and probably more severely than men as suggested by the higher frequencies of insulin administration.

Adolescent↗
PubMed1986

The role of glucagon, catecholamines and cortisol in counterregulation of insulin-induced hypoglycemia in normal man.

To study the response of glucose counterregulation to insulin-induced hypoglycemia, six normals were given a 4-hour infusion of insulin (2.4 U/h) +/- somatostatin (50 micrograms/h). Supplementary glucagon (1.5 or 3.0 ng/kg/min) was given in additional experiments. In a separate study, glucagon was supplemented for 4 hours as a constant rate infusion (3.25 ng/kg/min) or at rates stepwise increasing from 1.5 to 5.0 ng/kg/min. Insulin decreased blood glucose by 1.5 mmol/l and simultaneous suppression of glucagon resulted in a more pronounced hypoglycemia enhancing the adrenaline and cortisol responses. The hyperglycemic effect of glucagon substitution (3 ng/kg/min) faded out after about 2 hours, whereafter exaggerated adrenaline and cortisol responses to hypoglycemia were seen. A comparison between the effects of steady state hyperglucagonemia and gradually appearing hyperglucagonemia on the counterregulation of hypoglycemia revealed no significant differences in glucose, adrenaline and cortisol responses to insulin. It is concluded that the glycemic effect of glucagon is transient in the hypoglycemic state. When the hepatic responsiveness to this hormone is decreased during hypoglycemia, adrenaline becomes the essential protective factor.

Adult↗
PubMed1986

Glipizide does not affect absorption of glucose and xylose in diabetics without residual beta-cell function.

We have previously demonstrated that oral glipizide suppresses the absorption of xylose in diabetics treated with diet alone. We suggested that glipizide might influence postprandial glucose levels by interfering with absorptive mechanisms. In the present study we have extended our observations to insulin-dependent diabetics (IDDM). Nine non-obese diabetics without residual beta-cell function and with normal respiratory sinus arrhythmia and Valsalva ratio were studied on two occasions. Their ordinary insulin treatment was discontinued 24 hours before the study and glucose control was maintained by i.v. insulin infusion. The experiments began at 8 a.m. after an overnight fast. Insulin was given as a continuous i.v. infusion of 0.01 U/kg/h at 8-11 a.m. and 0.005 U/kg/h at 11 a.m. -2 p.m. At 8 a.m. the patients ingested 25 g of xylose and 15 g of glucose in 300 ml of water. Glipizide (5 mg) or placebo were given 30 min prior to the glucose-xylose load in random order, each patient serving as his own control. Blood samples were taken every 60 min for analysis of glucose, xylose, C-peptide and glipizide. The rise in blood glucose in the control experiment was similar to that previously seen in non-insulin-dependent diabetics (NIDDM) given the same xylose-glucose load. Glipizide did not exert any effects on either blood C-peptide, glucose or xylose levels. We conclude that oral glipizide administered in a therapeutic dose does not reduce xylose absorption in IDDM, in contrast to its previously demonstrated effect in NIDDM.

Adult↗
PubMed1986

Counterregulation of insulin-induced hypoglycaemia in primary hypothyroidism.

Hypothyroidism has been alleged to modulate insulin action and influence the secretion of growth hormone and catecholamines. We recently investigated the influence of hypothyroidism on glucose counter-regulatory capacity and the hormonal responses to insulin-induced hypoglycaemia in 6 patients with primary hypothyroidism (age 32-52 years, TSH-values 66-200 mU/l). Hypoglycaemia was induced in the hypothyroid state and again when the subjects were euthyroid. After an overnight fast a constant rate infusion of insulin (2.4 U/h) was given for 4 h. Glucose was measured every 15 min and insulin. C-peptide, glucagon, epinephrine, norepinephrine, growth hormone and cortisol every 30 min for 5 h. During insulin infusion somewhat higher concentrations of the hormone were obtained in the hypothyroid state and simultaneously glucose levels were 0.5 mmol/l lower. As expected, basal norepinephrine levels were higher in hypothyroidism. However, no increase in circulating norepinephrine during hypoglycaemia was registered in the two experiments. The responses of counterregulatory hormones showed an enhanced response of cortisol, similar responses of growth hormone and epinephrine while the glucagon response was paradoxically impaired. Our findings suggest that hypothyroidism alters insulin metabolism, and that the glucagon response to hypoglycaemia is impaired in this condition.

Adult↗
PubMed1986

Plasma aldosterone-plasma renin activity ratio. A simple test to identify patients with primary aldosteronism.

Thirty-two patients with hypertension and recurrent hypokalaemia were investigated on the suspicion of primary aldosteronism. On the basis of unsuppressible aldosterone secretion upon oral mineralocorticoid administration in 16 patients, a surgical exploration was made revealing a typical aldosteronoma in 12 of them, macronodular hyperplasia in two, micronodular hyperplasia in one, and micronodular hyperplasia together with a phaeochromocytoma in one patient. The remaining 16 patients with normal aldosterone suppressibility were considered to have primary hypertension. The discriminatory power of various biochemical tests related to the renin-angiotensin-aldosterone axis was analyzed in retrospect. The only parameter allowing a separation of patients with biochemically and surgically confirmed primary aldosteronism from the other group was the plasma aldosterone-plasma renin activity ratio. The present study therefore confirms the diagnostic value of this ratio for identifying patients with primary aldosteronism.

Adult↗
PubMed1985

Effects of previous intake of glucose on postprandial hyperglycemia in type 2 diabetics.

Previous glucose improves subsequent glucose tolerance (the Staub-Traugott effect) in normal man. We have investigated whether a small amount of glucose (5 g) given perorally 30 min before breakfast would improve postprandial hyperglycemia in type 2 diabetics (19 patients). Blood glucose was increased 30 min after glucose ingestion (from 7.6 +/- 0.4 to 8.7 +/- 0.4 mmol/l, p less than 0.001). Total glucose areas measured between the time of glucose ingestion and 180 min after breakfast were similar during test and control conditions (breakfast alone). Apparent differences between individuals with regard to the effects of previous glucose on hyperglycemia were further analyzed. Differences could not be explained by interexperimental variation since they persisted on repeated testing (3 patients). Differences were not correlated with age, sex, duration of diabetes, obesity, fasting blood glucose or the insulin responses evoked in the experiments. We conclude that a small amount of glucose before breakfast fails to ameliorate postprandial hyperglycemia in overt type 2 diabetics except in individual patients in whom, in turn, the effect is not directly related to insulin secretion.

Adult↗
PubMed1985

Effect of improved glycemic control by continuous subcutaneous insulin infusion on hormonal responses to insulin-induced hypoglycemia in type 1 diabetics.

Glucose counter-regulatory capacity and the hormonal responses to insulin-induced hypoglycemia were studied in eight type 1 diabetics before and after improvement of metabolic control by continuous subcutaneous insulin infusion (CSII). The intensified treatment resulted in a decrease in mean glycosylated hemoglobin from 11.6 +/- 0.5 to 9.3 +/- 0.4% within a mean period of 14 weeks. During a constant rate infusion of insulin (2.4 U/h), steady state levels of glucose appeared in all subjects. The steady state glucose level was identical before and after CSII. The counter-regulatory hormonal responses showed significantly higher epinephrine levels, while glucagon, growth hormone, and cortisol were not influenced. In parallel with the heightened epinephrine response the pulse rate response was significantly enhanced. The restitution of blood glucose after insulin hypoglycemia was not modified. It is concluded that a more vigorous catecholaminergic response to hypoglycemia is achieved after improved metabolic control by CSII.

Adult↗
PubMed1985

Genetics and clinical significance of thyroxine binding globulin deficiency, an analysis of seven families.

Seven families, ascertained through probands with undetectable levels of thyroxine binding globulin (TBG) were studied from clinical and genetic points of view. The blood levels of TBG, thyroxine binding prealbumin (TBPA), thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4) were determined in altogether 128 family members. The concentration of free thyroxine (FT4) was calculated from the concentrations of T4, TBG and TBPA. Only men (n = 15) were found to have total TBG deficiency. Their TSH levels were within normal range and they did not show any clinical symptoms of thyroid dysfunction. The mothers and daughters of the affected men had significantly lower TBG levels than control women. Segregation analysis performed on 46 nuclear families showed significant evidence for an X-linked additive mode of transmission and an additional multifactorial component with heritability 0.47.

Adolescent↗
PubMed1985

Aminoglutethimide and metyrapone in the management of Cushing's syndrome.

Fifteen patients with endogenous Cushing's syndrome were treated with metyrapone and/or amino-glutethimide. The duration of the therapy varied from 19 up to 365 days. In patients with Cushing's disease, metyrapone (0.5-2.5 g/day) and aminoglutethimide (0.5-1.5 g/day) seemed equally effective in reducing the cortisol excretion (54 +/- 9 vs 40 +/- 7%). The majority of these patients also showed a clinical improvement. In 1 patient with adrenal adenoma, metyrapone induced a remission. In another patient with adrenocortical cancer, and in 2 with the ectopic ACTH syndrome, the cortisol excretion was significantly reduced by the combination of metyrapone and aminoglutethimide but no obvious clinical improvement was observed. Side effects i.e. rash and pruritus attributed to aminoglutethimide was seen in 3 patients which necessitated the omission of treatment in 2. On metyrapone a moderate hypertrichosis was observed in 1 patient. In conclusion both metyrapone and aminoglutethimide were useful as adjunctive therapy in Cushing's syndrome.

ACTH Syndrome, Ectopic↗
PubMed1985

The effects of intravenous insulin infusion on skin microcirculatory flow in Type 1 diabetes.

The effects of insulin infusion (1.5 u/h and 15 u/h) on finger nailfold capillary diameter, microcirculatory resting flow and microvascular reactivity were studied in eleven Type 1 diabetics. Blood glucose was maintained at pre-infusion values by intravenous glucose infusion as necessary. Venous limb capillary diameter was significantly wider on 15 u/h compared with pre-infusion values (14.3 +/- 4.5 micron pre, 16.9 +/- 5.1 micron 15 u/h, p less than 0.01. Resting blood flow measured by laser doppler flowmetry increased on the low dose infusion compared with pre-infusion values (2.6 +/- 1.7 V pre, 3.3 +/- 1.9 V 1.5 mu/h, p less than 0.05) but fell on high dose infusion (2.5 +/- 1.9 V, p less than 0.02). Dynamic measurement of capillary blood flow velocity in single capillaries suggested that insulin infusion increased the circulatory debt repayment following 60 s arterial occlusion. The high dose infusion caused a significant impairment of the reflex rise in precapillary resistance that normally accompanies venous congestion. It is concluded that insulin has effects on skin microvascular haemodynamics that are independent of the hormone's hypoglycaemic action.

Adult↗
PubMed1984

Impaired counter regulation of hypoglycemia in a group of insulin-dependent diabetics with recurrent episodes of severe hypoglycemia.

The counterregulatory response to insulin-induced hypoglycemia was investigated in 22 insulin-dependent diabetics (IDD) with recurrent hypoglycemia and in 6 healthy volunteers. Hypoglycemia was induced by a constant rate infusion of insulin (2.4 U/h) up to four hours. Conventional insulin therapy was changed to an i.v. infusion of regular insulin 24 hours prior to the experiment. The presence of diabetic autonomic neuropathy was evaluated by respiratory sinus arrhythmia and Valsalva maneuver. In healthy subjects, blood glucose was decreased to 2.5 mmol, here reaching steady state level and giving rise to marked glucagon and growth hormone (GH) responses. The majority of IDD (group A) reached a slightly lower steady state glucose level and exhibited similar glucagon and GH responses while the epinephrine response was augmented. Six IDD (group B) showed a continuous decrease in blood glucose to 1.2 +/- 0.1 mmol/l at which level the infusion of insulin was discontinued due to neuroglucopenic symptoms. These subjects had no glucagon and epinephrine responses while their GH and cortisol responses were normal. A comparison of the diabetic groups revealed a longer duration of diabetes and a more impaired autonomic nervous function in group B while glycosylated hemoglobin was similar. It is concluded that most IDD have normal hormonal responses (epinephrine, glucagon, GH, cortisol) and normal counterregulartory capacity to hypoglycemia induced by a prolonged infusion of a moderate dose of insulin. Some patients with long-term diabetes and impaired capacity to counteract hypoglycemia exhibit deficient glucagon and epinephrine responses to hypoglycemia.

Adult↗
PubMed1984

Extrapancreatic effects of a sulphonylurea. Decrease in xylose absorption by glipizide in type II diabetics.

The effects of glipizide on the absorption of glucose and d-xylose were studied in six type II diabetics on diet treatment alone. Glipizide was given intravenously (12 micrograms/kg at 0 min) or orally (5 mg at -30 min). Oral glucose (15 g) and xylose (25 g) loads were given at zero time. Glipizide stimulated insulin secretion and reduced glucose and xylose levels significantly with both routes of administration. The suppression of xylose levels lasted longer after oral than after intravenous administration of the drug. It is suggested that part of the influence of glipizide on postprandial glucose levels may represent interference with absorptive mechanisms.

Administration, Oral↗
PubMed1983

Minimal increases in glucagon levels enhance glucose production in man with partial hypoinsulinemia.

In man a small dose of somatostatin (50 micrograms/h) suppressed moderately basal insulin (5 microU/ml) and glucagon (40 pg/ml) levels. This resulted in a short-lasting hypoglycemia, which was then followed by marginal hyperglycemia throughout the experiment. The addition of a minimal dose of glucagon (0.50 ng/kg/min) to somatostatin normalized basal glucagon levels and resulted in a significant and sustained hyperglycemia. During the first 2 h, hyperglycemia was mainly due to increased glucose production, whereas later on it was maintained by decreased glucose uptake. We conclude that, in man moderately deprived of insulin, even a marginal change in glucagon level induces a long-lasting hyperglycemia.

Adult↗
PubMed1982

Effect of somatostatin on insulin-induced hypoglycemia in man.

In order to study the interaction of insulin and somatostatin on glucose regulation in the posthypoglycemic phase of a somatostatin infusion we have applied a bolus of i.v. insulin to healthy subjects receiving a continuous infusion of somatostatin. Glucose, insulin and counterregulatory hormones were determined. Somatostatin suppressed the growth hormone and glucagon responses to hypoglycemia but did not augment the hypoglycemic action of insulin. In contrast, the K-value for the decrease in blood glucose was significantly lower in the presence of somatostatin. Thus, the interaction of insulin and somatostatin on glucose metabolism is complex and time-dependent. While the peptide potentiates the action of insulin during the first hour of somatostatin infusion, it counteracts if after two hours. As somatostatin has currently been introduced in the therapy of upper gastrointestinal bleedings, these effects of the peptide must be taken into consideration.

Adult↗
PubMed1982

The question of early insulin response to glucose in patients with ischemic heart disease: a retrospective study in twins. Preliminary communication.

The genetic determination of the early insulin response (EIR) to a standard intravenous glucose load and the relation between EIR and manifestations of ischemic heart disease (IHD) by means of ECG abnormalities was studied in 18 monozygotic (MZ) and 13 dizygotic (DZ) twin pairs aged 53-76 years. Intrapair variances for EIR and basal glucose was significantly smaller in MZ than DZ twins, indicating that genetic factors are of importance for the regulation of these two parameters. No genetic influence on glucose tolerance was found. In DZ twins discordant with respect to pathologic Q waves (Minnesota Code 1.1), significantly lower EIR was found in twin partners with Q wave abnormality. These findings also point to an association between low EIR and IHD.

Aged↗