Effectiveness of the iodine prophylaxis model adopted in Poland.

OBJECTIVE: Most of the Polish territory has been classified as an iodine-deficient and endemic goiter area according to the International Council for Control of Iodine Deficiency (ICCIDD) criteria. In 1997 the obligatory model of iodine prophylaxis was implemented. Our investigations were aimed at the effectiveness of iodine prophylaxis in Poland. METHODS: We assessed urinary iodine excretion and goiter prevalence in 5663 children aged 6-12 yr. The population of children from the same 27 schools was investigated from 1992 to 1994 (1406 girls and 1244 boys) and from 1999 to 2005 (1563 girls and 1450 boys) using identical laboratory and ultrasound methods. RESULTS: We found significant increase in iodine urinary concentration (median 52 microg/l vs 93 microg/l, p<0.001) with accompanying drop in goiter prevalence (29.6% vs 5.2%, p<0.001) after implementation of iodine prophylaxis. Iodine excretion distribution changed significantly after 1997 with an increase in the percentage of children with iodine urinary concentration above 100 microg/l from 10.8% to 45.4%, respectively. A significantly higher iodine urinary concentration was observed in lowlands compared to uplands both before and after implementation of iodine prophylaxis (median, 50 microg/l vs 57 microg/l and 86 microg/l vs 114 microg/l, respectively, p<0.001). The goiter prevalence did not differ between girls and boys from 1992 to 1994 (28.8% vs 30.5%, p=0.35) and 1999 to 2005 (5.5% vs 4.9%, p=0.45). CONCLUSIONS: Implementation of the new model of iodine prophylaxis in Poland in 1997 has led to significant increase in iodine urinary concentration and decrease in goiter prevalence among Polish schoolchildren. In the youngest group of children (6-8 yr olds), prevalence of goiter decreased to 3.2%--i.e. below endemic levels.

Homocysteine concentrations and vascular complications in patients with type 2 diabetes.

OBJECTIVE: Hyperhomocysteinemia is a well known risk factor for the diseases of the cardiovascular system, which seem to be the main cause of increased mortality in patients with type 2 diabetes. The aim of the study was to evaluate the levels of homocysteine in patients with type 2 diabetes in respect to the regimen of diabetes treatment as well as the presence of diabetic complications. METHODS: The investigation was carried out in the group of 64 patients with type 2 diabetes and in 18 healthy subjects from the control group. Clinical examination and measurements of homocysteine, folic acid, vitamin B12, glycosylated hemoglobin concentration and evaluation of parameters of the lipid metabolism, microalbuminuria and creatinine were done in both groups. RESULTS: Homocysteine concentration was significantly higher in the group of patients with diabetes in comparison to the control group (p = 0.0007). Diabetic patients had significantly lower concentrations of folic acid (p = 0.028) and HDL cholesterol (p = 0.025) together with higher levels of systolic blood pressure (p = 0.007). In the group of patients with diabetes no differences in homocysteine levels were found in respect to diabetes treatment. Diabetic patients with coronary artery disease had significantly higher homocysteine concentration in comparison to the group with diabetes without history of coronary artery disease (p = 0.0097). Homocysteine levels correlated significantly with incidence of ischaemic heart disease (r = 0.44, p = 0.001) and microalbuminuria (r = 0.26, p = 0.019). Negative correlation was noticed in HDL concentrations (r = -0.30, p = 0.013) and the levels of folic acid (r = -0.30, p = 0.008). CONCLUSION: Our results suggest that hyperhomocysteinemia in diabetic patients may contribute to the development of chronic complications. The influence of diabetes treatment on Hcy levels requires further observations.

L-selectin gene T668C mutation in type 1 diabetes patients and their first degree relatives.

There have been some studies published recently which have suggested that L-selectin and/or other adhesion molecules could be the new markers for diabetes type 1 risk development in humans and animal models of the disease. The alterations of soluble L-selectin have been found not only in overt but also in the preclinical stage of disease development and were independent from the presence of ICA - a marker of ongoing autoimmunity, but associated with HLA related genetic predisposition to insulin-dependent diabetes mellitus (IDDM). The aim of our study was to evaluate the frequency of the L-selectin gene T668C mutation (from thymine to cytosine at position 668) resulted in F206L an amino acid substitution in patients with overt diabetes and their unaffected first degree relatives in comparison to the unselected control population. In the unaffected siblings of IDDM subjects we have observed a significantly higher frequency of the L-selectin gene T668C mutation in comparison to their relatives with type 1 diabetes and healthy controls. It was also shown that there is an association between T668C mutation and low HLA related risk of IDDM development, the highest frequency of F206L mutation in the EGF domain of L-selectin was observed in relatives with 'protective' HLA DQB1*0602 allele and nonDRB1*03-nonDRB1*04 haplotype, while in subjects with highest risk of IDDM haplotype the frequency of T668C mutation was similar to the controls. We would like to hypothesise that the T668C L-selectin gene mutation could have a (protective?) role in the development of IDDM, but further studies concerning their role in type 1 diabetes are needed.

CD11a expression and soluble ICAM-1 levels in peripheral blood in high-risk and overt type 1 diabetes subjects.

A pair of correspondent adhesion molecules: LFA-1 (CD11aCD18) and ICAM-1 (CD54) was shown to be involved in autoimmune insulitis in animal models. Anti-LFA-1 or anti-ICAM-1 monoclonal antibodies administered in vivo had a very strong preventive effect on the development of spontaneous diabetes with a marked reduction of insulitis. On the other hand elevated levels of the soluble form of ICAM-1 (sICAM-1) were documented in subjects at risk for type 1 diabetes. Recently sICAM-1 was shown to play an immunoregulatory role as an inhibitor of islet insulitis. The aim of the present study was to evaluate CD11a + mononuclear cells (lymphocytes and monocytes) and soluble sICAM-1 levels in the peripheral blood of subjects with preclinical and overt type 1 diabetes to assess their role in the development of the autoimmune process and their possible associations with the humoral autoimmune markers. The study was carried out in three groups of subjects: 26 first degree relatives of type 1 diabetes patients (prediabetics) with the combinations of autoantibodies against pancreatic B cells (ICA, GADA, IA-2A, IAA), 22 patients with a recent onset of type 1 diabetes and age and sex-matched 24 healthy volunteers (control group). We observed an increased fluorescence intensity of CD11a on mononuclear cells in overt diabetes subjects and a positive correlation between CD11a fluorescence intensity on monocytes and ICA titre. The highest sICAM-1 levels we obtained in the peripheral blood in the prediabetics in comparison to patients with clinical diabetes and the healthy controls. We found a positive correlation between slCAM-1 and values of ICA, GADA and a total number of antibodies present. In conclusion our study suggests that LFA-1 and sCAM-1 play an important role in the pathogenesis of type 1 diabetes. The assessment of the CD11a bearing monocytes and sICAM-1 levels are potential markers of the preclinical stage of the autoimmune diabetes, but further prospective studies in high risk diabetes type 1 subjects are needed.

Gammadelta T-cells alterations in the peripheral blood of high risk diabetes type 1 subjects with subclinical pancreatic B-cells impairment.

There is increasing evidence that CD3 + cells bearing gammadelta T-cell receptor (represent the minor subpopulation of the T-cells in the peripheral blood in humans) are involved in autoimmunity development. Gammadelta T-cell receptor (TCR)+ /CD8+ T-cells have been recently found to play a critical role in the pathogenesis and prevention of autoimmune diabetes in the animal model. The aim of the present study was the estimation the gammadelta T-cell subpopulation levels in the peripheral blood of subjects with preclinical and overt type 1 diabetes and their possible associations with the humoral immunity, metabolic parameters and pancreatic B-cells function. The study was carried out in three groups of subjects: 26 first degree relatives of type 1 diabetes patients (prediabetics) with the combinations of autoantibodies against pancreatic B-cells (ICA, GADA, IA-2A, IAA), 22 patients with a recent onset of type 1 diabetes and age and sex-matched 24 healthy volunteers (control group). A decrease was observed in the absolute numbers and percentages of gammadelta+ /CD8+ and gammadelta+ /CD8- T-cell subpopulations in peripheral blood in the prediabetics with the impaired first phase of insulin secretion in comparison to relatives with autoantibodies but still with normal B-cells function, patients with clinical diabetes and healthy controls. In conclusion, the study suggests that the gammadelta T-cells play an important role in the development of insulin-dependent diabetes mellitus (IDDM). It is possible that their levels in the peripheral blood could be an additional marker of preclinical detection of the disease, but further prospective studies in high risk of IDDM subjects are needed.

Serum L-selectin and ICAM-1 in patients with Graves' ophthalmopathy during treatment with corticosteroids.

UNLABELLED: Circulating forms of L-selectin were found to be elevated in several autoimmune diseases. ICAM-1 has been suggested a predictor of the onset of GO. The aim of the study was an estimation of serum L-selectin and ICAM-1 in patients with Graves' disease with ophthalmopathy during treatment with corticosteroids to assess their potential as a guideline of immunosuppressive therapy. We detected serum L-selectin and ICAM-1 in three groups of subjects: 20 patients with Graves' disease without ophthalmopathy (Gd), 17 patients with clinical symptoms of ophthalmopathy (CAS> or =3, anamnesis of GO> or =1 year) and 24 healthy volunteers. Corticosteroid therapy consisted of intravenous infusions of methyloprednisolone (MP) and subsequent treatment with oral prednisone (P). The serum samples were collected 24 h before MP, 24 h after MP, 12+/-2 days of treatment with prednisone and after the end of the corticosteroid therapy. The levels of soluble L-selectin and ICAM-1 in the serum were determined by the ELISA method. The statistical significance was estimated by the Mann-Whitney U-test. Serum L-selectin and ICAM-1 were significantly increased in patients with GO (respectively 1182+/-222 and 438+/-68 ng/ml) and in patients with Graves' disease without ophthalmopathy (respectively: 1168+/-130 and 343+/-109) in relation to the controls. After MP treatment in corticosteroid-responsive patients (improvement in CAS < or =1) serum concentration of L-selectin and ICAM-1 decreased significantly and gradually increased during subsequent treatment with prednisone. In corticosteroid-responsive patients serum L-selectin was significantly higher before MP administration and after P treatment in relation to corticosteroid-resistant subjects. CONCLUSIONS: 1. Serum L-selectin and ICAM-1 were elevated in patients with active GO 2. Methyloprednisolone decreased levels of the studied adhesion molecules in corticosteroid-responsive patients with GO 3. Lack of clinical results in corticosteroid therapy in patients with a low starting L-selectin level would suggest the possibility of serum L-selectin estimation as a prognostic for immunotherapy efficacy.

Insulin, leptin, IGF-I and insulin-dependent protein concentrations after insulin-sensitizing therapy in obese women with polycystic ovary syndrome.

OBJECTIVE: To determine the clinical, hormonal and biochemical effect of 4-5 months of insulin-sensitizing therapy (hypocaloric diet+metformin) in obese patients with polycystic ovary syndrome (PCOS). DESIGN: Prospective study. METHODS: Twenty-three obese patients with PCOS, 19 obese patients without menstrual disturbances and 11 healthy control women were recruited from the Department of Endocrinology and Endocrine Gynecology, Medical Academy, Bialystok, Poland. Obese patients received 500 mg metformin together with hypocaloric diet three times daily for 4-5 months, after baseline study. The clinical parameters, menstrual pattern and serum concentrations of insulin, leptin, IGF-I, insulin-dependent proteins (sex hormone-binding protein (SHBG), insulin-like growth factor-binding protein-1 (IGFBP-1)), gonadotropins and sex steroids were determined before and after treatment. RESULTS: In the baseline study, obese patients with PCOS had significantly higher insulin, testosterone and LH concentrations in comparison with the other groups. The serum leptin, IGF-I, IGFBP-1 and SHBG were not different between the two groups of obese patients, but there was a significant difference in comparison with the control group. After metformin therapy a significant reduction in BMI, % of body fat and leptin concentration were observed in both groups of obese patients. Fasting insulin, testosterone and LH concentrations decreased significantly only in the PCOS group. Six out of 11 patients in the PCOS group had more regular menstrual cycles; two patients conceived. CONCLUSIONS: Insulin-sensitizing therapy could be considered as an additional therapeutic option in obese women with PCOS.

Changes in tumor necrosis factor-alpha system and insulin sensitivity during an exercise training program in obese women with normal and impaired glucose tolerance.

OBJECTIVE: Tumor necrosis factor-alpha (TNFalpha) plays an important role in the pathogenesis of insulin resistance and type 2 diabetes. Plasma levels of the soluble (s) fractions of TNFalpha receptors, especially sTNFR2, are good indicators of TNFalpha system activation in obesity. The aim of the present study was to assess the effect of exercise training on the TNFalpha system and to evaluate the relationship with changes in insulin sensitivity. DESIGN AND METHODS: Sixteen obese women (body mass index (BMI)>27.8 kg/m(2)), 8 with normal (NGT) and 8 with impaired glucose tolerance (IGT), participated in an exercise training program which lasted for 12 weeks and included exercise performed on a bicycle ergometer at an individual intensity of 70% maximal heart rate, for 30 min, 5 days a week. Anthropometrical measurements and blood biochemical analyses were performed, and plasma TNFalpha, sTNFR1 and sTNFR2 levels were assessed. Insulin sensitivity was evaluated using the hyperinsulinemic euglycemic clamp technique (insulin infusion: 50 mU x kg(-1)xh(-1)). RESULTS: At baseline, despite similar anthropometrical parameters, IGT subjects were markedly more insulin resistant and had higher TNFalpha and sTNFR2 concentrations. Exercise training increased insulin sensitivity and decreased TNFalpha and sTNFR2 levels, while sTNFR1 remained unchanged. The decrease in sTNFR2 was significantly related to the increase in insulin sensitivity; that relationship remained significant after adjustment for the concurrent changes in BMI, waist circumference, percentage of body fat, plasma glucose, insulin and free fatty acids. CONCLUSIONS: Regular physical exercise decreases TNFalpha system activity and that decrease may be responsible for the concurrent increase in insulin sensitivity.

A programme of iodine supplementation using only iodised household salt is efficient--the case of Poland.

BACKGROUND: Iodine prophylaxis in Poland started in 1935 and has been interrupted twice: by World War II and in 1980 for economic reasons. Epidemiological surveys carried out after the Chernobyl accident in 1989 as well as in 1992/1993 and in 1994 as a 'ThyroMobil' study, revealed increased prevalence of goitre in children and adults. Ninety per cent of Poland was classified as an area of moderate iodine deficiency, and 10%, in the seaside area, as mild iodine deficiency territory. Iodine prophylaxis based on iodisation of household salt was introduced again in 1986 as a voluntary model and in 1997 as a mandatory model with 30+/-10 mg KI/kg salt. OBJECTIVE: The evaluation of the obligatory model of iodine prophylaxis in schoolchildren from the same schools in 1994 and 1999. METHODS: Thyroid volume was determined by ultrasonography. Ioduria in casual morning urine samples was measured using Sandell-Kolthoff's method, within the framework of the ThyroMobil study. RESULTS: Goitre prevalence decreased from 38.4 to 7% and urinary iodine concentration increased from 60.4 to 96.2 microg/l mean values between 1994 and 1999. In four schools the prevalence of goitre diminished below 5%. In 1999, 70% of children excreted over 60 microg I/l, and 36% over 100 microg I/l, whereas in 1994 the values were 44 and 13% respectively. CONCLUSION: The present findings indicate that iodine prophylaxis based only on iodised household salt is highly effective.

A pilot study of the effect of the glycosaminoglycan sulodexide on microalbuminuria in type I diabetic patients.

Fifteen out-patients with type I diabetes mellitus and microalbuminuria (mean +/- SEM: 95.4 +/- 13.9 micrograms/min), were administered the glycosaminoglycan sulodexide, with the aim of investigating its influence on the rate of albumin excretion. Sulodexide was given intramuscularly in a dose of 600 lipoproteinlipase releasing units/day for three weeks. Albumin excretion was measured before dosing, at weekly intervals during dosing and also during the subsequent follow-up period of six weeks. Sulodexide yielded a clear-cut and statistically significant lowering of albumin excretion after the first week of treatment (from 95.4 +/- 13.9 micrograms/min to 53.6 +/- 11.1 micrograms/min; p = 0.0055); albumin excretion was further decreased after three weeks of treatment (26.5 +/- 6.05 micrograms/min; p = 0.0007) and was maintained during the follow-up period, at the end of which the mean value was still significantly lower than at baseline (39.6 +/- 10.3 micrograms/min; p = 0.01). Sulodexide short-term administration did not influence the routine haematological, haematochemical and coagulative tests performed contemporaneously. Patients' compliance with treatment was very good and no adverse events were reported.

The effect of exercise training on glucose tolerance and skeletal muscle triacylglycerol content in rats fed with a high-fat diet.

The aim of the present study was to evaluate the effect of exercise training on glucose tolerance and glycogen and triacylglycerol (TG) content in different types of skeletal muscles and in the liver of rats fed with a high-fat diet. From 8 to 11 weeks of age male Wistar rats were fed with isocaloric standard (control) or high-fat diet (HFD--59% calories as fat) and were additionally assigned to a sedentary or trained group (4 weeks of training on a treadmill). An intravenous glucose tolerance test (IVGTT) with the determination of basal and post load insulin was performed before the final tissue sampling. HFD rats developed marked hyperinsulinemia. Exercise training improved glucose tolerance and insulin response in the control group only (AUC for glucose in control sedentary vs control trained, p<0.05; AUC for insulin: control sedentary vs control trained, p<0.005). Liver glycogen was significantly lower in the HFD group (p<0.05 vs control sedentary) and did not increase after exercise training. Muscle and liver TG content was markedly higher in the HFD group in comparison to control (p<0.0001 in all cases). Exercise training increased TG content in the control group in all examined tissues except white gastrocnemius (p<0.001 in all cases compared to sedentary controls), and did not affect tissue TG in the HFD group. After exercise training there was still markedly higher tissue TG content in the HFD group vs control (p<0.0001 in all cases). We conclude that beneficial metabolic effects of training are impaired in high-fat fed rats and that training does not completely reverse metabolic disturbances in this group of animals.

Nicotinamide inhibits enhanced in vitro production of interleukin-12 and tumour necrosis factor-alpha in peripheral whole blood of people at high risk of developing type 1 diabetes and people with newly diagnosed type 1 diabetes.

Macrophages and T lymphocytes are the first cells to appear in pancreatic islets in the development of autoimmune diabetes. It has been suggested that cytokines released by monocytes/macrophages, including interleukin-1beta (IL-1beta), interleukin-12 (IL-12) and tumour necrosis factor-alpha (TNF-alpha) could have an initial role in islet B-cell damage. The aim of the present study was to estimate the effect of human insulin and nicotinamide on the levels of monocyte/ macrophage derived cytokines in the peripheral blood of humans at risk of Type 1 diabetes, and in patients with newly diagnosed Type 1 diabetes compared to healthy control subjects. The study was carried out on three groups of subjects: 20 first degree relatives of people with Type 1 diabetes (with two or more antibodies against pancreatic B-cell antigens); 22 patients with recent onset of Type 1 diabetes (duration of the disease 3-6 months); and 25 age- and sex-matched healthy subjects. Cytokine levels (IL-1beta, IL-12, and TNF-alpha) in the supernatants of whole blood cultures incubated with PHA alone (10 microg/ml), or PHA + human insulin (50 microg/ml), or PHA + nicotinamide (100 micromol/l) were quantified by ELISA. In the cultures with nicotinamide the concentration of IL-12 and TNF-alpha was significantly lower in the prediabetic group, diabetic patients, and the healthy controls than in the cultures with PHA only or with PHA + insulin. There were no significant differences in IL-1beta production in the cultures after incubation with the different stimuli in the studied groups and healthy controls. No significant influence of human insulin on macrophage/monocyte cytokines secretion in in vitro cultures of the peripheral blood was found. This suggests that nicotinamide could influence monocyte/macrophage function in peripheral blood by inhibiting production of IL-12 and TNF-alpha.

Effect of glycosaminoglycans on urinary albumin excretion in insulin-dependent diabetic patients with micro- or macroalbuminuria.

The aim of this study was to investigate whether sulodexide treatment is capable of influencing urinary albumin excretion rate (UAER) in insulin-dependent diabetes mellitus patients (type I) with micro- or macroalbuminuria. A total of 14-inpatients (seven with micro and seven with macroalbuminuria) were enrolled and were treated first intramuscularly with a 60 mg vial of sulodexide/day for 10 days, and then orally with 25 mg capsules twice a day for 21 days. UAER was estimated before starting treatment (T0), after the i.m. treatment phase (T1) and at the end of the oral treatment (T2). No statistically significant differences in hematochemical and coagulative parameters were registered after treatment, with respect to basal values. On the contrary, a marked decrease in UAER mean values was registered at the end of both the parenteral and the oral treatment periods (T0: 349.9 mg/24 h, range 80-820; T1: 237 mg/24 h, range 7-620; T2: 91.4 mg/24 h, range: 2-306). All the differences were statistically significant (P < 0.001) versus baseline. At T2, a normalisation of UAER was observed in three microalbuminuric and in two macroalbuminuric patients, and a remarkable decrease was found in additional four and five patients, respectively. UAER was found to be still significantly lower than at baseline after 6 weeks of follow-up. This preliminary study suggests that sulodexide is effective in reducing UAER in type I patients with diabetic nephropathy.

Abnormal distribution of gammadelta T lymphocytes in Graves' disease and insulin-dependent diabetes type 1.

There is an increasing evidence that CD3+ cells, bearing gammadelta T cell receptors representing a minor subpopulation of T cells in the peripheral blood of humans are involved in the development of autoimmunity. The aim of the present study was determination of the gammadelta T cell subpopulation levels in the peripheral blood of subjects with Graves' disease and newly diagnosed type 1 diabetes in comparison to age-matched healthy controls. The percentages of CD3+, CD8+, gammadelta TCR+CD8+, gammadelta TCR+CD8- lymphocyte subsets were measured by flow cytometry. In the peripheral blood of newly diagnosed Graves' disease patients we showed a significant decrease of gammadelta TCR+ cells and gammadelta TCR+CD8- subset content in comparison to the percentages observed in subjects after methimazole treatment and in healthy controls. We also found a significant increase of gammadelta TCR+CD8+ cells in the peripheral blood of subjects with insulin-dependent diabetes, treated with insulin for 3-6 months. The present findings confirm our previous hypothesis that gammadelta TCR+CD8+ lymphocyte subset could play a role in the pathogenesis of diabetes type 1, probably as regulatory T cells and could be induced by delivery of exogenous insulin. Our results suggest that gammadelta T cells (gammadelta TCR+CD8- subset) could also play an important role in the development of Graves' disease and that their levels are modulated by thyreostatic treatment.

In vitro secretion of interleukin 2 and expression of IL-2 receptor in peripheral blood lymphocytes in high risk of insulin-dependent diabetes mellitus subjects.

Interleukin 2 (IL-2)--a Th1 lymphocyte-derived cytokine is at present considered to play an important role in the etiopathogenesis of insulin-dependent diabetes mellitus. In the previous studies increased, decreased and unchanged IL-2 levels in patients with recent onset of insulin-dependent diabetes mellitus (IDDM) were found. These differences could be a result of different metabolic status or/and a different stage of the autoimmune process. The aim of our study was to estimate in vitro secretion of IL-2 and CD25 antigen expression by the peripheral blood T lymphocytes in subjects at the preclinical stage of IDDM (prediabetes), but still without metabolic disturbances. In 27 first degree relatives of IDDM patients with antibodies against different pancreatic islet cell antigens (ICA, GADA, IAA, IA-2) CD25 antigen expression on peripheral blood lymphocytes T was measured by flow cytometry and IL-2 concentration in supernatants of 48 and 72 h cultures of peripheral whole blood with 10 microg/ml PHA was estimated by ELISA. The control group was comprised of 34 age and sex-matched healthy volunteers. In the studied high risk IDDM subjects the decreased CD25 expression in peripheral CD4+ lymphocytes T and a negative correlation between the percentage of CD25+ cells and islet cell antibodies (ICA) titres was observed. No differences in IL-2 levels in supernatants of 48 h and 72 h blood cultures was found in subjects with single antibody (ICA+) in comparison to healthy controls. A significant increase of IL-2 secretion at 72 h of PHA stimulation was shown in first degree relatives of IDDM patients with a combination of 3 or more antipancreatic-B cell antibodies. There were also a significant negative correlation between glutamic acid decarboxylase antibodies (GADA) titres and IL-2 levels in 72 h of culture. The present study suggests the involvement of IL-2 in the pathogenesis of IDDM. The estimation of CD25 antigen expression in the peripheral blood lymphocytes could be an additional immunological marker of identification of subjects in prediabetes.

The effect of fasting and physical exercise on plasma leptin concentrations in high-fat fed rats.

The aim of our study was to estimate the effect of fasting and physical exercise on a treadmill on plasma leptin concentrations in high-fat fed rats. Male Wistar rats were injected a low dose of streptozotocin (STZ) or buffer at 2 days of age and later fed a standard or high-fat diet (HFD). Plasma leptin was measured by RIA method in all the groups studied in basal conditions, after 48h fasting, a single bout of exhaustive exercise, and 4 weeks of exercise training. Plasma leptin concentrations were markedly elevated in the HFD and STZ/HFD groups compared to the control group. The significant correlation between plasma leptin and body weight was noted. Fasting and exercise training decreased plasma leptin in similar percentage in all the groups studied. The observed decrease was greater than expected from changes in body weight. We conclude that high-fat feeding results in an increase in plasma leptin levels in rats independently of plasma insulin or daily calorie intake. High-fat fed rats have maintained leptin response to fasting and exercise training. The reduction in plasma leptin after exercise training is partly independent on changes in body weight or plasma insulin.

The effect of a single bout of exhaustive exercise on muscle carbohydrate and lipid metabolism in a rat model of type 2 diabetes mellitus.

The aim of the present study was to estimate whether a single bout of exhaustive exercise influences the glycogen and triglyceride (TG) content in red and white gastrocnemius muscle and in the liver of rats with experimental type 2 diabetes. Experiments were carried out on male Wistar rats fed from 8 to 11 weeks of age with isocaloric standard or high-fat diet (HFD) with a previous injection of low-dose of streptozotocin (STZ) or vehicle at 2 days of age (I, control group; II, HFD; III, STZ; IV, STZ + HFD). Group IV (STZ + HFD) represents a model of type 2 diabetes. Basal liver glycogen was markedly lower in all the studied groups compared to controls. Glycogen concentration after exercise fell significantly in the examined tissues in all groups in comparison to basal conditions. A significant TG accumulation in examined tissues was observed in all the studied groups in comparison to controls. Exercise decreased tissue TG content in all the groups, but it remained significantly higher in the experimental groups vs. control. We conclude that in this model of type 2 diabetes, a single bout of exercise reveals defective utilization of tissue carbohydrates and lipids.

Antioxidant therapy and streptozotocin-induced diabetes in pregnant rats.

The aim of our study was to analyse the effect of chronic hyperglycaemia on lipid peroxidation and scavenging enzyme activity in pregnant animals and their offspring supplemented and not supplemented with vitamin E - a natural antioxidant. Thirty pregnant female Wistar rats were used in our experiments. Diabetes was induced on day 7 of pregnancy using a single does of streptozotocin (40 mg/kg). Diabetic animals were divided into two equal groups: vitamin E supplemented and those fed with standard diet. Our controls consisted of 15 healthy rats. On day 1 after delivery homogenates of maternal liver and uterus as well as neonatal lungs and liver were prepared. Then the following parameters were measured: malondialdehyde (MDA) concentrations in the homogenates and blood serum, glutathione (GSH) levels, the activity of CuZn superoxide dismutase (SOD) and glutathione peroxidase (GPx) (Bioxytech, France). Statistical analysis was performed using Mann-Withney U test. The neonates of diabetic rats were smaller than those from healthy rats and serum glucose concentration was markedly higher in diabetic animals, both in mothers and neonates. MDA levels increased significantly, whereas GSH content and SOD as well as GPx activities were markedly diminished in diabetic pregnant rats and their offspring in comparison with the control group. In animals supplemented with tocopherol, MDA concentrations declined significantly, GSH contents and SOD activities were markedly elevated in almost all types of tissues studied, whereas glutathione peroxidase remained suppressed. Our results suggest that diabetic pregnant rats and their neonates are exposed to oxidative stress (OS), but vitamin E supplementation could in part reduce the imbalance between uncontrolled reactive oxygen species generation and scavenging enzyme activity, and may potentially serve as a useful prophylactic factor against OS development:

Lipid peroxidation and scavenging enzyme activity in streptozotocin-induced diabetes.

The aim of this study was to evaluate lipid peroxidation and scavenging enzyme activity in streptozotocin-induced diabetes, and then to establish whether moderate doses of nonenzymatic antioxidant vitamin E play a role in the antioxidant defence system in diabetic pregnant rats and their offspring. The study group consisted of 30 normal female Wistar rats, which were given a single dose of streptozotocin (40 mg/kg) and were mated 7 days later. Subsequently, the diabetic animals were divided into two matched groups: the first supplemented with vitamin E (30 mg/100 g chow), and the other fed with a standard diet lacking vitamin E. Controls consisted of 15 pregnant rats. On the first day after delivery, the rats were decapitated and homogenates of maternal liver and uterus as well as neonatal lungs and liver were prepared. Then the following parameters were measured: malondialdehyde (MDA) concentrations in the homogenates and blood serum, glutathione (GSH) levels, the activity of CuZn-superoxide dismutase (SOD) and glutathione peroxidase (GPx), and glycaemia. The neonates of diabetic rats were smaller than the healthy ones and serum glucose concentration was markedly higher in the diabetic animals. MDA levels were significantly increased, whereas GSH, SOD and GPx were markedly diminished in the diabetic adult rats and their offspring in comparison to the control group. In the animals supplemented with alpha-tocopherol, MDA concentrations were significantly lower, GSH content and SOD activities were markedly elevated most tissues studied, whereas GPx remained unchanged. We conclude that, by monitoring the activity of selected scavenging enzymes, information on ongoing biological oxidative stress and thereby on the fetus/neonate status may be obtained. Our results suggest that diabetic pregnant rats and their neonates are exposed to an increased oxidative stress and that vitamin E supplementation may reduce its detrimental effects.

Post-partum evaluation of amylin in lean patients with gestational diabetes mellitus.

The aim of our study was to compare the secretion of amylin, as well as glucose, insulin and C-peptide at baseline and in response to glucagon stimulation in 26 lean women with gestational diabetes mellitus (GDM) and in 19 age- and BMI-matched pregnant women with normal glucose tolerance (NGT). Intravenous 1-mg glucagon stimulation test was performed 6 weeks after delivery. Fasting and stimulated glucose levels were significantly higher in GDM patients than in subjects with NGT ( p<0.01 at 0 and 6 min; glucose area under the curve (AUC), 604.8+/-41.8 mg/6 min vs. 572.4+/-52.4 mg/6 min, p<0.05). Insulin AUC was also markedly higher in GDM subjects than in healthy controls (373.9+/-144.2 micro IU/6 min vs. 283.7+/-139.1 micro IU/6 min, p<0.05). There was no difference in fasting C-peptide levels between the groups studied, but stimulated concentrations, as well as C-peptide AUC were significantly higher in patients with GDM ( p<0.01 at 1 min and p<0.005 at 6 min; AUC, 27.4+/-11.3 pmol/6 min vs. 18.4+/-6.9 pmol/6 min, p<0.01). Amylin levels were higher in GDM group in comparison to healthy subjects ( p<0.005 at 1 and 6 min; amylin AUC, 113.3+/-51.2 pg/6 min vs. 72.5+/-15.7 pg/6 min; p=0.14), but in contrast to the other hormones, did not rise in response to glucagon injection. In conclusion, our results provide evidence that in patients with GDM in the post-partum period, the levels of amylin, as well as the secretion of insulin and C-peptide remain elevated, when compared to women with NTG. Further investigations are needed to clarify the significance of this elevation as a predictive factor for the development of late maternal type 2 diabetes.