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Biomedical subjects

M Krotkiewski

Publications and source records attributed to M Krotkiewski.

At least 55 records · Page 3Linked to original sources
PubMed1986

Muscle adaptations and glucose control after physical training in insulin-dependent diabetes mellitus.

Six men and three women with insulin-dependent diabetes (without complications) participated in physical training three times a week for 20 weeks. Physical training did not change the concentration of fasting blood-glucose, glucose excretion in urine or glucosylated haemoglobin (HbA1). However, the glucose disposal rate during euglycaemic clamp increased after training. In two patients a minor reduction of insulin dosage was necessary to alleviate slight hypoglycaemic episodes. The training resulted in significant increases in quadriceps isometric and dynamic strength and endurance. Maximal oxygen uptake increased by 8%, the activity of glycolytic enzymes in vastus lateralis muscle by 47% for hexokinase, and 30% for tri-osephosphate dehydrogenase and 25% for lactic dehydrogenase, the activity of oxidative enzymes by 42% for citrate synthase and 46% for 3-hydroxy-acyl-CoA-dehydrogenase. The glycogen concentration in the vastus lateralis muscle did not change significantly. Lipoprotein lipase activity did not change in muscle, nor in adipose tissue. The mean muscle fibre area increased by 25% and the area of FTa fibres by 30%. The new formation of capillaries around different muscle fibres was significant for FTb fibres (26%). The proliferation of capillaries, however, appeared to be insufficient to cope with the increased area of muscle fibres. As a result, the mean area of muscle fibre supplied by one capillary (a measure of diffusion distance) significantly increased after training for FTa fibres. It is concluded that with the exception of deficient proliferation of capillaries, patients with insulin-dependent diabetes mellitus show a normal central and peripheral adaptation to physical training. Physical training does not apparently improve blood glucose control in most cases, despite an increased insulin sensitivity.

Adaptation, Physiological↗
PubMed1986

Effect of muscular exercise on plasma C-peptide and insulin in obese non-diabetics and diabetics, type II.

The levels of plasma insulin and C-peptide during exercise and subsequent recovery have been determined in obese non-diabetics, obese diabetics Type II and middle-aged female controls. It has been found that exercise reduces levels of peptides both in the control and in the obese non-diabetic group. This effect of acute exercise was found blunted in the obese diabetic group. Non-diabetic obese subjects pretreated with phentolamine showed no reduction either in plasma insulin or C-peptide levels during exercise. During the recovery, the level of plasma insulin returned promptly to the pre-exercise value in the control group but increased above the resting value in obese subjects, both non-diabetic and diabetic. In controls and non-diabetic obese the increment of C-peptide: insulin molar ratio occurred early after the onset of exercise and then returned to the resting value despite the exercise being continued. The plasma C-peptide:insulin molar ratios were reduced during the first 15 min of recovery period in obese non-diabetic subjects and returned to normal in the next 15 min. The latter may suggest that reduced insulin removal could also contribute to the increase in plasma insulin values in the obese during recovery.

Blood Glucose↗
PubMed1986

Muscle tissue in obesity with different distribution of adipose tissue. Effects of physical training.

Obese men and women with the same body fat mass, as well as obese women in another study, were divided into groups with male or female type of body fat distribution, but again with similar body fat mass. The participants were examined with measurements of body composition, including muscle fiber distribution, as well as circulatory and metabolic variables before and after physical training under controlled conditions. Obese men had higher lean body mass, blood pressure, blood glucose and plasma insulin, C-peptide, cholesterol and triglyceride concentrations than age- and body fat-matched obese women. Obese women with male type of adipose tissue distribution showed the same differences (except cholesterol) in comparisons with women with female type of adipose tissue distribution. The women with male type obesity were also more insulin resistant in glucose clamp measurements, and had male type of muscle fiber distribution. Physical training in the group of obese men resulted in a decrease of body fat, a further increase of lean body mass, an increase of fast twitch, aerobic type, muscle fibres as well as lower plasma insulin, cholesterol and triglyceride concentrations and lower blood pressure. Obese women with male type distribution of adipose tissue responded to physical training essentially like men. The insulin sensitivity was improved to the same level as in obese women with female type of adipose tissue distribution. In contrast, the latter women showed an increase of body fat and no metabolic improvements after training. These results show that obese women with male type of body fat distribution also have male characteristics of muscle mass, morphology and function. It is suggested that the obesity complications associated with this condition are improved by physical training because of an adaptation to a negative energy balance, in combination with an improvement of insulin sensitivity of the muscle mass. In contrast, the failure of obese women with female type of adipose tissue distribution to adapt to a negative energy balance during physical training is probably explaining their failure to decrease body fat and to improve metabolism during physical training.

Adipose Tissue↗
PubMed1985

The effects of physical training on insulin secretion and effectiveness and on glucose metabolism in obesity and type 2 (non-insulin-dependent) diabetes mellitus.

Obese subjects with normal glucose tolerance (n = 55), and, in another study, a group of patients with Type 2 (non-insulin-dependent) diabetes (n = 33), and controls (n = 13) matched for body weight and age but with normal glucose tolerance, participated in an individualized physical training program for 3 months. Under controlled dietary conditions, metabolic studies were performed before and in steady state after the last exercise session after training in the subjects showing signs of physical training in VO2 max and heart rate measurements. No changes occurred in body weight, body cell mass, body fat or adipose tissue cellularity. Oral glucose tolerance was improved in the patients with diabetes mellitus only. In both diabetic and control subjects initially elevated C-peptide concentrations decreased, while low C-peptide values increased and which was particularly pronounced in diabetic subjects with subnormal values. Peripheral insulin values did not change. Glucose disposal rate measured with the glucose clamp technique was similar in diabetic patients and control subjects. An improvement was seen at both submaximal and maximal insulin levels in both groups, correlating with improvement in glucose tolerance in the diabetic subjects. No changes were found in adipocytes in insulin binding or the antilipolytic effect of insulin at submaximal insulin levels, but there was a normalization of a decreased glucose incorporation into triglycerides. These results indicate that both insulin secretion and effectiveness are altered by physical training in different ways in different clinical entities. They suggest that in insulin resistant conditions with high insulin secretion (as indicated by high C-peptide concentrations) the increased peripheral insulin sensitivity is followed by a decreased insulin secretion. This is not associated with an improvement of glucose tolerance. In Type 2 diabetes with low insulin secretion, an increased insulin secretion results from physical training, perhaps due to accompanying sensitization of the autonomic nervous system. Peripheral insulin concentrations are not altered, suggesting that the extra insulin produced is captured by the liver. This mechanism, as well as the improved peripheral insulin responsiveness seen in the whole body and also seen at the cellular level, probably both contribute to an improvement in glucose tolerance.

Adipose Tissue↗
PubMed1985

Non-response of muscle capillary density and lipoprotein-lipase activity to regular training in diabetic patients.

Ten obese women with normal glucose tolerance, 10 obese patients with sulphonylurea-treated non-insulin-dependent diabetes (NIDD) and 11 patients with insulin-dependent diabetes (IDD; treated for 3-31 yr) took part in a 10-week programme of physical training in 50-min sessions, 2-3 times a week. As a result of training, maximal oxygen uptake increased significantly by about 18, 13 and 8% in the 3 groups, respectively, and citrate synthase in muscle increased significantly by 27-42%. The lipoprotein-lipase activity in muscle tissue (sampled by a needle-biopsy technique from the lateral vastus muscle) did not change. The number of capillaries/fibre in muscle tissue increased. This was accompanied by an increase in muscle fibre area, resulting in an unchanged number of capillaries/mm2. This may explain why the lipoprotein-lipase activity was unaltered. The latter activity in the group with IDD was lower than was predicted from the number of capillaries/mm2. This number was in fact larger than in the obese and NIDD groups. These results indicate that the increase in capillary density and lipoprotein-lipase activity that occurs in healthy young individuals as an effect of endurance training does not take place in obese, NIDD and IDD patients.

Adult↗
PubMed1984

Physical training in obese women. Effects of muscle morphology, biochemistry and function.

Peripheral adaptations to 3 months of physical endurance training without food restrictions were studied in skeletal muscles of 14, middle-aged, physically untrained, obese women. In comparison to aged-matched controls of normal weight, the obese group showed significantly lower isometric endurance. In the obese group, physical training resulted in a significant increase of maximal isometric and isokinetic strength. Isokinetic but not isometric endurance also increased after training. The isometric strength of obese women showed a positive correlation with the percentage of FTb fibres. The training (50 min/day, 3 days/w) did not result in any change in body weight, body fat, and the number and weight of fat cells. The 20% increase of VO2 max after training was found to be significantly correlated with the increase in the number of capillaries around muscle fibres. The relative percentage of FTa fibres, the number of capillaries per fibre as well as the activities of citrate synthase, 3-hydroxy-acyl-CoA-dehydrogenase, and hexokinase showed a significant increase after training. The concentrations of glucose during OGTT showed a trend to decrease with a significant decrease at the end glucose curve (120-min value). The concentration of insulin and C peptide and the insulin removal did not change after training. The changes in the concentration of glucose during OGTT was significantly correlated with the increase in muscle capillarization and of dynamic endurance.

Adult↗
PubMed1984

Effect of guar gum on body-weight, hunger ratings and metabolism in obese subjects.

The effect of a palatable granulated guar-gum preparation (10 g twice daily) was studied in obese subjects. The acute effect of a single dose of guar gum to reduce the peak postprandial whole blood glucose levels (about 10%) was verified. Following long-term treatment, a further reduction was seen in the obese subjects with the highest postprandial glucose levels. Since the postprandial plasma insulin levels were essentially unchanged, this finding suggested an increased responsiveness to insulin. Total serum cholesterol levels were significantly reduced following long-term treatment but serum alpha-cholesterol levels, representing the high-density-lipoprotein fraction, was unchanged. Body-weight was significantly reduced during guar-gum treatment even though the patients were asked to maintain their normal dietary habits. Daily hunger ratings recorded for up to 10 weeks showed that guar gum reduced hunger significantly better than commercially available bran taken in the same way. Thus, guar gum seemed to influence carbohydrate and lipid metabolism in a beneficial way in obese subjects. The reduction in hunger would offer an additional benefit to these patients.

Adult↗
PubMed1984

The effect of acute and chronic exercise on thyroid hormones in obesity.

Thyroid hormones were measured before, during and after acute exercise (60 min) or physical training (3 months) in obese women. Thyroid stimulating hormone concentration increased during acute work and decreased immediately after. No changes were seen during the two following days. An increase was seen after ten days as well as after three months of physical training. Thyroxine concentrations showed no changes. 3,5,3'-Triiodothyronine decreased slightly immediately after acute exercise, and after three months of physical training, 3,3',5'-triiodothyronine (reverse triiodothyronine) increased slowly during and after acute exercise. A negative correlation was found between changes in fasting insulin and thyroxine and a positive correlation between changes in blood pressure and triiodothyronine after training. Lack of agreement in previous reports is probably due to methodological differences such as methods more or less susceptible to fatty acid interference, and thyroid hormones changing differently during acute work and before and after physical training. The duration of the study may also be of importance, even 3 months possibly being too short for attaining equilibrium in thyroid homeostasis.

Exercise Test↗
PubMed1984

Effects of physical training on insulin, connecting peptide (C-peptide), gastric inhibitory polypeptide (GIP) and pancreatic polypeptide (PP) levels in obese subjects.

Ten severely obese women were subjected to physical training for three months on ad libitum diet. Under metabolic ward conditions oral glucose tolerance test was performed before and after the training period with the same energy intake quantitatively and qualitatively, and glucose, insulin, connecting (C)-peptide, gastric inhibitory polypeptide (GIP) and pancreatic polypeptide (PP) were determined. In confirmation of previous work, physical training caused no decrease in body fat in these severely obese subjects, and no change in body cell mass or glucose tolerance, while insulin and blood pressure decreased. The control of dietary conditions demonstrated that the latter phenomena were not due to quantitative or qualitative changes in the diet. C-peptide concentrations decreased also, indicating effects of physical training in obesity on insulin production. GIP is believed to be a gastrointestinal factor facilitating insulin secretion (Incretin). Previous work has indicated that gastrointestinal factor(s) are involved in the insulin lowering effect seen after physical training. It is possible that GIP is contributing to this phenomenon.

Adipose Tissue↗
PubMed1983

Relationship between muscle morphology and metabolism in obese women: the effects of long-term physical training.

To evaluate the relationships between changes in muscle morphology and metabolic adaptation to physical training in obesity, twenty obese women were subjected to a physical training programme with three sessions a week for 3 months. Physical training resulted in lowering of plasma insulin and improved glucose tolerance. Neither body weight nor body fat changed. With physical training the percentage distribution of fast twitch oxidative (FTa) muscle fibres (m vastus lateralis) increased (from 30.3 +/- 5.1% to 35.2 +/- 4.8%, P less than 0.05) and that of fast twitch glycolytic fibres decreased (from 18.3 +/- 6.6 to 5.8 +/- 4.8%, P less than 0.05). The number of capillaries increased, mainly around slow twitch (ST) fibres (from 4.5 +/- 0.6 to 5.8 +/- 0.8, P less than 0.01) and fast twitch oxidative (FTa) fibres (from 3.9 +/- 0.7 to 4.7 +/- 0.8, P less than 0.01). The activities of oxidative enzymes (cytochrome-c-oxidase and citrate synthase) increased (P less than 0.05) while those of glycolytic enzymes (phosphofructokinase and hexokinase) decreased after physical training (P less than 0.01). Significant negative correlations between plasma insulin and number of capillaries in contact with ST fibres (r = 0.80, P less than 0.001) and FTa fibres (r = 0.62, P less than 0.001) were found before training. The capillary density around those fibres could predict 80% of the explained variance of plasma insulin levels (P less than 0.001). The changes of glucose concentration after training could be predicted by observed changes in enzyme activities. The strong associations between muscle morphology and capillarization and enzyme activities and glucose and insulin concentrations and their changes after training suggest an important regulatory role of muscle which warrants further studies.

Adult↗
PubMed1983

Effects of physical training on adrenergic sensitivity in obesity.

To examine the possibility that the decrease of hyperinsulinemia and blood pressure in obesity associated with physical training is mediated via adaptations in the adrenergic nervous system, a pure beta-adrenergic agonist (isoproterenol) or an alpha-adrenergic antagonist (phentolamine) was infused before and during an oral glucose tolerance test before and after physical training. A number of circulatory, metabolic, and endocrine factors under adrenergic control were followed. Physical training was associated with an augmented beta-agonist response in blood pressure, heart rate, blood glucose, plasma insulin, connecting (C) peptide, and pancreatic polypeptide (PP) but not in plasma glucagon and gastric inhibitory polypeptide. Physical training also resulted in higher values of C-peptide and PP values after alpha-adrenergic blockade. It was concluded that physical training probably is associated with an augmented sensitivity of the beta-adrenergic nervous system. This might also be the case with the alpha-adrenergic system. It was suggested that this in turn might be due to a decreased firing in the adrenergic nervous system leading secondarily to an increased sensitivity in the effector cells. It was hypothesized that such decreased firing could provide a background to explain lower blood pressure and plasma insulin after physical training.

Adult↗
PubMed1983

Impact of obesity on metabolism in men and women. Importance of regional adipose tissue distribution.

The distribution of adipose tissue thickness, fat cell weight (FCW), and number (FCN) were studied in four regions in randomly selected middle-aged men and women and in 930 obese individuals. Both the obese and the randomly selected men were found to have the largest adipose tissue thickness in the abdominal region. Women, however, showed a relative preponderance for the gluteal and femoral regions. FCW increased with expanding body fat up to a maximal size of approximately 0.7-0.8 micrograms/cell in each region. After this increase in FCW, a more rapid increase in FCN was found. For the same degree of relative overweight, men had higher triglyceride, fasting glucose, and insulin levels; higher sums of glucose and insulin levels during an oral glucose tolerance test; and higher blood pressure. Furthermore, elevated fasting glucose levels (greater than 7.4 mM) occurred twice as often in the males. These differences between males and females persisted even after body fat matching. A male risk profile was seen in women characterized by abdominal obesity (high waist/hip circumference ratio) as compared to women with the typical peripheral obesity. Stepwise multiple regression analyses in both women and men showed the obesity complications to be associated in a first step to waist/hip circumference or body fat and in a second to abdominal fat cell size. It may thus be concluded that: (a) In both obese and nonobese subjects, regional differences exist between the sexes with regard to adipose tissue distribution. (b) Moderate expansion of body fat is mainly due to FCW enlargement, which is subsequently followed by increased FCN. (c) Men and women with a male abdominal type of obesity are more susceptible to the effect of excess body fat on lipid and carbohydrate metabolism.

Abdomen↗
PubMed1983

Insulin binding and responsiveness in fat cells from patients with reduced glucose tolerance and type II diabetes.

Adipose tissue was obtained from 66 individuals including 21 patients with type II diabetes of different severity (16 SU-treated and 5 diet-treated only) as well as 9 obese subjects with reduced glucose tolerance. Adipocyte insulin binding, antilipolytic effect of insulin, and glucose incorporation into triglycerides were measured in the diabetic and the obese subjects and the data compared with that of normal controls of similar age and relative weight. Insulin binding per cell was normal in the diabetic patients and was significantly increased at low insulin concentrations in the obese patients with reduced glucose tolerance, suggesting increased affinity. Furthermore, insulin binding correlated negatively with age but, when age was corrected for, did not correlate significantly with fasting insulin or glucose levels, relative body weight, or fat cell size. Insulin sensitivity, measured as the antilipolytic effect of insulin, was similar in all patient groups. Patients with the most severe type II diabetes (SU-treated group) demonstrated, in contrast to the less severely diabetic patients, a marked reduction in both basal and insulin-stimulated glucose incorporation into triglycerides showing the presence of a pronounced postreceptor defect. The insulin effect on glucose incorporation correlated negatively with the fasting glucose levels, suggesting that the postreceptor defect seen in the adipocyte reflects perturbations in other organs, like muscle or liver, of greater importance for glucose homeostasis.

Adipose Tissue↗
PubMed1983

Physical training in the prophylaxis and treatment of obesity, hypertension and diabetes.

The results of physical training in 600 obese and 100 diabetic patients are described and discussed. Three months of physical training (55 min 3 times/week) without dietary restriction did not result in any change in body weight and composition either in obese or diabetic female patients. However, the male patients remained their body weight unchanged and body fat decreased and lean body mass increased after training. The combination of exercise with a very low calorie diet in obese women neither prevents the erosion of lean body mass nor the diet-induced decrease in oxygen uptake. Local exercise could not evoke a local decrease in the thickness of adipose tissue. The addition of physical training to the low calorie diet leads to better social and psychological compliance and a more equal distribution of adipose tissue. A close relationship has been found between the muscle morphology and glucose metabolism in obese patients. Insulin concentration appeared to be positively correlated to the percentage of FTb fibers and inversely correlated to the capillary density. The decrease in the percentage of FTb muscle fibers and the increase in the number of capillaries were correlated to the decrease in plasma insulin levels. The capillary density appeared to be reduced with decreasing degrees of glucose tolerance. In patients with diabetes type I it was found diminished so much that the diffusion distance in muscle increased after training. The most interesting results related to glucose metabolism were found otherwise as follows: The sum of insulin (276.4 +/- 20.1 before and 255.1 +/- 19.0 after p less than 0.05) and glucose levels (but not fasting values) decreased (28.3 +/- 1.6 before and 27.8 +/- 1.4 after p less than 0.01) after training in obesity. In obese and diabetic patients with initially high insulin values physical training resulted in a decrease in insulin level, while in those patients with initially low values it resulted in an increase. As judged from the insulin C-peptide ratio, patients who decreased their insulin levels after training increased their liver uptake of insulin. The increased hepatic extraction of insulin without the decrease of insulin production was also noted in patients with diabetes type II. After training both obese patients and those with diabetes I and II increased their glucose metabolism (disposal rate) during insulin euglycemic clamp. Patients with diabetes type II showed initially lower basal and insulin-stimulated glucose incorporation into triglycerides.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Physiological↗