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Biomedical subjects

S Madsbad

Publications and source records attributed to S Madsbad.

At least 109 records · Page 6Linked to original sources
PubMed1985

Changes in plasma volume, in transcapillary escape rate of albumin and in subcutaneous blood flow during hypoglycaemia in man.

Hypoglycaemia was induced by insulin injected intravenously (0.15 i.u./kg body weight) in seven healthy young males. Plasma volume was measured before and during hypoglycaemia by intravenous injection of 125I before hypoglycaemia and of 131I during hypoglycaemia. Plasma volume decreased and transcapillary escape rate increased significantly during hypoglycaemia. Skin temperature and local subcutaneous adipose tissue blood flow were measured in four different regions. Both tended to decrease during hypoglycaemia and decreased significantly 2 h after hypoglycaemia. There was no correlation between changes in the two measurements, suggesting that there is no simple relationship between subcutaneous blood flow and skin temperature during hypoglycaemia.

Adult↗
PubMed1985

Immunoreactive gastric inhibitory polypeptide response to a meal during the first eighteen months after diagnosis of type 1 (insulin dependent) diabetes mellitus.

The changes in plasma concentrations of immunoreactive gastric inhibitory polypeptide (IR-GIP) in response to a standard meal were examined in 21 normal subjects and 15 Type 1 (insulin dependent) diabetic patients 7 days, 14 days, and 3, 6, 9, 12, and 18 months after time of diagnosis. During the first 4 tests significantly lower plasma IR-GIP concentrations were found in the diabetic patients after the standard meal. At 9 months and during the remaining tests there was no difference in IR-GIP concentrations between the diabetic and the normal subjects. The IR-GIP response was normalized faster if the diabetic patients were treated with initial short term intensive insulin therapy than if they were treated conventionally with 1 or 2 daily injections of insulin. beta-Cell function, evaluated by the C-peptide response to the meal, increased significantly during the first 3 months. After 3 months maximal beta-cell function was found while the corresponding IR-GIP responses were significantly lower than those of the normal subjects. Thereafter beta-cell function declined gradually and significantly, coinciding with the normalization of the IR-GIP response. No individual covariation between IR-GIP and beta-cell function during the 18 months was found in any patient. The IR-GIP response to a meal was diminished at the onset of Type 1 (insulin dependent) diabetes mellitus. After the start of insulin therapy the response improved, perhaps as a function of the quality of metabolic control, and within a year it was comparable to that of normal subjects. Lack of endogenous GIP therefore does not explain the diminished beta-cell function in Type 1 diabetes a few months after onset of the disease. No causal relationship between the changes in beta-cell function and IR-GIP during the first 18 months after the onset of the disease seems to exist.

Adolescent↗
PubMed1985

The importance of plasma free insulin and counterregulatory hormones for the recovery of blood glucose following hypoglycaemia in type 1 diabetics.

After induction of hypoglycaemia in 31 Type 1 (insulin-dependent) patients, the 10 patients with the slowest recovery of blood glucose from hypoglycaemia were arbitrarily compared with the 10 patients with the fastest recovery of blood glucose. No differences were found between the two groups regarding response of glucagon to hypoglycaemia, whereas the epinephrine (2-fold), norepinephrine (2.4-fold) and cortisol responses were significantly greater in the group with the slow recovery. The plasma free insulin concentrations were higher (2-fold) in the group with slow recovery from 30 min after stop of insulin and throughout the study. This may be explained by a 3-fold greater amount of insulin binding antibodies in this group compared to the group with fast recovery from hypoglycaemia. An inverse significant correlation was demonstrated between the rates of recovery and the amounts of insulin binding antibodies in all the patients (P less than 0.02). This implicates that enhanced counterregulatory hormone responses in the group with the slow recovery from hypoglycaemia could not compensate for the hypoglycaemic effect of a concomitant higher plasma free insulin concentration. Insulin binding antibodies, acting as a depot of circulating insulin, may be a risk factor of prolonged hypoglycaemia in Type 1 diabetics.

Adolescent↗
PubMed1985

The effect of insulin deprivation on fasting levels of 5000 dalton gastric inhibitory polypeptide in type 1 (insulin-dependent) diabetics.

To investigate whether metabolic decompensation has an effect on gastric inhibitory polypeptide (GIP), 8 fasting male type 1 diabetics were deprived of insulin for 12 h. An overnight insulin infusion aiming at normoglycaemia was stopped at 08.00 h. During the following 12 h blood glucose increased from 7.0 +/- 0.4 to 14.9 +/- 1.0 mmol/l, P less than 0.01, 3-hydroxy-butyrate from 0.18 +/- 0.07 to 4.00 +/- 0.74 nmol/1, P less than 0.01, and immunoreactive GIP (IR-GIP) from 16.7 +/- 2.6 to 21.9 +/- 2.9 pmol/1, P less than 0.05. The antiserum employed, R65, only measures 5000 dalton IR-GIP. The final IR-GIP concentrations were not significantly different from fasting IR-GIP concentrations in 13 normal male subjects (17.4 +/- 1.5 pmol/1). Short term insulin deprivation therefore is associated with a slight increase in fasting IR-GIP concentrations. Whether this modest increase in IR-GIP significantly enhances insulin secretion is unknown.

3-Hydroxybutyric Acid↗
PubMed1984

Evaluation of two methods of rapid blood-glucose monitoring by unskilled personnel during surgery.

The accuracy of two rapid methods of blood-glucose monitoring without (Haemo-glucotest 1-44) and with a reflectance meter (Hypocount B) was compared using a laboratory method. The assessment was carried out by personnel with no previous experience in measuring blood glucose. Eighty-five percent of the 92 measurements obtained with the hypocount B were within +/- 20% of the laboratory glucose values. Using haemo-glucotest 1-44 strips, 74% of the readings were within +/- 20% of the reference laboratory values. For values below 5.5 mmol/l, there was a tendency for results to be too low, with 77% of the readings below laboratory values -20%. All situations with severe hypoglycaemia were detected with both strips. The study also demonstrates the ineffectiveness of s.c. insulin regimens during surgery. Only 47% of the measured blood glucose values were within the range of 5.5-10 mmol/l and two of ten patients had hypoglycaemia with values below 2.5 mmol/l. Therefore glucose monitoring during surgery in diabetics seems justified. This monitoring can be performed adequately with strips.

Adult↗
PubMed1984

Effects of surgical stress and insulin on cardiovascular function and norepinephrine kinetics.

In resting supine subjects the whole-body clearance of norepinephrine (NE) based on arterial and venous sampling averaged 1.4 and 2.5 liters/min, respectively (P less than 0.02). The difference in clearance values was due to a peripheral uptake of NE averaging 45%. The calculation of plasma NE clearance based on venous sampling results in values that are too high. The plasma appearance rate of NE increased considerably after surgery, whereas the arterial blood pressure remained unchanged. This suggests that the sensitivity to NE is reduced postsurgery. Insulin has certain acute effects on cardiovascular function and plasma NE kinetics that are unrelated to the counterregulatory response to decrements in plasma glucose concentration. Insulin may both induce antagonism to the action of NE and increase the release of NE from sympathetic nerves. Intravenous insulin decreases the plasma volume and increases the hematocrit by an adrenergic mechanism. Plasma NE increases in normal subjects after an oral glucose load. This response may be of importance because in sympathectomized patients both oral glucose and insulin administration decreases the arterial blood pressure. During an oral glucose load insulin-dependent diabetics show abnormalities in the regulation of cardiovascular function and sympathetic nervous activity that may be related to the lack of rise in endogenous insulin in these patients. These results suggest that insulin may be of importance for the normal function of the cardiovascular system.

Adult↗
PubMed1984

Relation of immunoreactive gastric inhibitory polypeptide to changes in glycaemic control and B cell function in type 1 (insulin-dependent) diabetes mellitus.

The effect of strict glycaemic control on plasma immunoreactive gastric inhibitory polypeptide (IR-GIP) concentrations and pancreatic B cell function as estimated by plasma C-peptide was evaluated in 14 Type 1 (insulin-dependent) diabetics. The effect was estimated by giving a test meal before (test 1) and after (test 2) 1 week with near normal blood glucose control (mean blood glucose 6.7 +/- 0.2 mmol/l) and again 3 weeks later (test 3) in the outpatient clinic. The glycaemic control was significantly improved at test 2 and test 3 compared with that of test 1. The IR-GIP concentrations before and after the meals were similar at all three tests and not different from those found in 21 normal controls. In 8 patients with a significant B cell response at test 1, B cell function was significantly improved both at test 2 and test 3 but no change in fasting or post-prandial IR-GIP concentrations was found and no correlation between B cell function and IR-GIP existed. We conclude that strict glycaemic control improves B cell function but does not modulate plasma IR-GIP concentrations. Factors other than GIP seem to be of greater importance in determining the magnitude of B cell function in Type 1 diabetes.

Adolescent↗
PubMed1984

A longitudinal study of virus antibodies in patients with newly diagnosed type 1 (insulin-dependent) diabetes mellitus.

Seventeen newly diagnosed type 1 diabetics were studied longitudinally--at diagnosis, after 5 months and after 2 years, for antibodies against the following viruses: Coxsackie B3, B4 and B5, Echo 11, and Adeno 7a. The latter two were chosen because they had been isolated frequently in the area during the year the patients were diagnosed, whereas the Coxsackie viruses previously have been associated with the aetiology of type 1 diabetes. Coxsackie B4 antibody titres fell from the diagnosis and the 5 month study to the 2 year study (p less than 0.02), and, at this time, the average titre was also lower than in 37 healthy control individuals (p less than 0.05). Over the same period Coxsackie B3 antibody titres increased (p less than 0.05). Echo 11 antibody titres were higher in the patients at diagnosis (p less than 0.05), but, otherwise, no significant titre differences, compared with controls or titre changes, were found at any of the study times. Patients with lower suppressor cell activity at diagnosis displayed higher mean antibody titres regarding the five viruses together, than did patients with higher suppressor cell activity (p less than 0.05). No significant correlations were found between, on the one hand, the antibody titres and, on the other hand, C-peptide values, insulin dosage, degree of glycaemic control, or specific tissue type, HLA-B8 or HLA-DR3 and/or 4.

Adenoviruses, Human↗
PubMed1984

Lack of negative feed-back regulation of insulin on the responses of gastric inhibitory polypeptide, insulin, glucagon and pancreatic polypeptide to a meal in insulin treated diabetics.

The effect of insulin on the secretion of immunoreactive gastric inhibitory polypeptide, insulin (as measured by C-peptide), glucagon and pancreatic polypeptide during and after a test meal was examined in seven diabetic patients treated with high insulin doses (mean 1.12 +/- 0.12 IU/kg X 24 h) before and after a reduction of the insulin dose (to 0.62 +/- 0.04 IU/kg X 24 h, p less than 0.02). While plasma insulin concentrations were significantly higher on the higher dose, no significant differences were found in the responses of immunoreactive gastric inhibitory polypeptide, C-peptide, glucagon and pancreatic polypeptide to the two meals. Blood glucose concentrations were not significantly different at the two tests. It thus seems that insulin has no direct effect on the secretion of these substances after a meal in insulin-treated diabetics.

Adult↗
PubMed1983

T lymphocyte subsets in patients with newly diagnosed type 1 (insulin-dependent) diabetes: a prospective study.

T lymphocyte subsets in peripheral blood from 11 newly diagnosed Type 1 (insulin-dependent) diabetic patients were studied prospectively at three time intervals: as soon as possible after diagnosis, 3 weeks and 5 months later. Lymphocytes were marked with monoclonal OKT antibodies and examined in a fluorescence-activated cell sorter. The percentage of T lymphocytes (OKT3) did not change significantly at the three study times. The percentage of helper/inducer T cells (OKT4) was high the first week after diagnosis, but decreased at the 5-month examination (p less than 0.05). The percentage of suppressor/cytotoxic T cells (OKT8) was low at diagnosis but increased at 3 weeks (p less than 0.02) and 5 months (p less than 0.01). The ratio OKT4/OKT8 lymphocytes was 2.28 at diagnosis, decreasing to 1.77 at 3 weeks and 1.87 at 5 months, compared with 1.46 for 16 age-matched control subjects. There was no significant change in the absolute number of lymphocytes. It is concluded that the distribution of T cell subsets was abnormal at the time of diagnosis, but changed towards normal within a few weeks, after which there was no significant change at 5 months. It is as yet unknown whether the high proportion of helper/inducer T cells and/or the low percentage of suppressor/cytotoxic T cells at diagnosis favour immune reactions involved in the pathogenesis of Type 1 diabetes.

Adolescent↗
PubMed1983

Plasma somatostatin increases during hypoglycaemia in insulin-dependent patients with and without B-cell function.

Responses of somatostatin-like immunoreactivity (SLI) to hypoglycaemia were investigated in seven type 1 (insulin-dependent) patients with residual B-cell function, eight patients without B-cell function, and six healthy controls. A higher basal level of SLI was found in the group with B-cell function when compared with the group without B-cell function. The basal level in the normal subjects was in between the two diabetic groups. All the diabetics had a somatostatin response to hypoglycaemia which was independent of residual B-cell function and no different from that of normal subjects.

Adolescent↗
PubMed1983

Response of pancreatic polypeptide to hypoglycaemia in insulin-dependent diabetics with and without residual beta-cell function.

To investigate a possible association between the beta-cells and the cells secreting pancreatic polypeptide (PP), the response of PP to insulin-induced hypoglycaemia was investigated in seven insulin-dependent diabetics with and seven without residual beta-cell function, all without signs of autonomic neuropathy. The mean concentrations of PP was significantly greater from 15 to 60 min after symptoms of hypoglycaemia in patients with residual beta-cell function than in patients without (P less than 0.05) despite similar blood glucose concentrations in the two groups. Also the total integrated areas beneath the response curves as well as the incremental integrated areas were significantly greater in patients with beta-cell function (216 +/- 36 pmol/l x min and 188 +/- 34 pmol/l x min, respectively) than in patients without beta-cell function (125 +/- 26 pmol/l x min and 102 +/- 26 pmol/l x min) (P less than 0.05 for both). The mean maximal concentrations of adrenaline (1.53 +/- 0.28 ng/ml v. 1.29 +/- 0.12 ng/ml) and noradrenaline (0.56 +/- 0.16 ng/ml v. 0.45 +/- 0.04 ng/ml) were not statistically different in the two groups. No well established explanation for an association between residual insulin secretion and capacity for PP-response to hypoglycaemia in type 1 diabetics exists.

Adult↗