PubMed Health⌕ Search

Biomedical subjects

V Růzicka

Publications and source records attributed to V Růzicka.

At least 19 recordsLinked to original sources
PubMed2002

Structures and pathways of the central nervous system are potentially involved in the serotonergic modulation of gastrointestinal activity.

The supposed involvement of rat brain regions in the modulation of rat small intestine serotonergic activity was investigated. Small electrolytic lesions were placed in the areas of medulla oblongata and pons Varoli; one week later, changes in the serotonergic response of the intestine were detected. The contractions mediated by the activation of 5-HT2 receptors in the proximal ileum were investigated. The whole ileum segments were cut and placed into the bath. The preparations were contracted by adding increasing concentrations of 5-hydroxytryptamine (5-HT) (10 nM-1 microM) and noncumulative concentration-response curves (CRCs) were established. The differences between 5-HT responses of preparations from either sham-operated or experimental rats suggest the existence of brainstem regions (dorsal vagal and solitary nuclei, parvocellular reticular nuclei and serotonergic A1,2,5 groups) that either stimulate or inhibit 5-HT modulatory action in the rat gastrointestinal tract.

Animals↗
PubMed2001

Osteoprotegerin, RANK, RANKL.

Osteoprotegerin, RANK (Receptor Activator of Nuclear factor kappa B) and RANKL (Receptor Activator of Nuclear faktor kappa B ligand) became the aim of intensive research. RANK is considered as a hematopoietic surface receptor controlling osteoclastogenesis and calcium metabolism. RANKL may promote osteoresorption by induction of cathepsin K gene expression. The present paper summarizes the most significant data in osteoprotegerin, RANK and RANKL problems obtained.

Animals↗
PubMed2001

Osteoprotegerin and bone density.

Aim of study was determine if a correlation exists between bone mass density and concentration of osteoprotegerin. We examined the group of 199 patients of mean age of 63 years. Of the group under study, 31 patients had normal bone density (T score > -1 and < 1) and 168 probands had osteopenia or osteoporosis (T < -1). Persons with normal BMD values had median values of OPG 60.8 ng/l, while patients with reduced bone density had median values of 73 ng/l OPG. Cut-off for reduction of bone density was 128 ng/l OPG. We demonstrated that OPG concentrations vary inversely with bone density values (correlation coefficient -0.31). These results suggest that determination of OPG could allow discrimination of individuals with normal bone density and those with reduced bone density.

Adult↗
PubMed1999

Determination of leptin receptor in the serum and relations to laboratory and anthropological parameters in patients with atherosclerotic complications.

Leptin receptors are supposed to have signal effects and are located in most tissues in the organism but we failed to find literary data on concentration (measurement) of leptin receptors in the system circulation. We examined by the method of randomized selection the group of 20 patients with manifested atherosclerosis in whom BMI was calculated. Then we analyzed concentration of leptin receptor (double sandwich ELISA, standard recombinant human leptin), leptin, glucose, insulin, proinsulin, CRP and uric acid in the serum. The control group consisted of 103 probands without signs of atherosclerosis or other manifested diseases. The control group was subjected to determination of BMI, leptin and leptin receptor in the serum. Concentration of leptin receptor does not differ significantly between the patients with atherosclerosis and normal population. Probands with atherosclerosis showed a very close negative correlation between concentration of leptin receptor and leptinemia which is absent in normal population.

Arteriosclerosis↗
PubMed1999

[Leptinemia in individuals with hypertension (pilot study)].

UNLABELLED: During the last decade several papers were published where obesity in included among the building stones of the so-called metabolic cardiovascular syndrome (along with hypertension, dyslipidaemia, impaired glucose tolerance and hyperinsulinaemia). Several months ago it was also revealed that some patients with the metabolic syndrome suffer from hyperleptinaemia. Leptinaemia is considered by some authors as independent indicator of the risk of accelerated atherosclerosis. The cause of these hypothesis were (in addition to the known conclusions on the occurrence frequent incidence of leptin resistance and insulin resistance) in particular the results of experimental studies where evidence was provided that infusion induced hyperleptinaemia leads in animals to hypertension due to its direct effect on sympathicotonia and peripheral vascular resistance. The authors of these hypothesis assume that hyperleptinaemia (in particular in subjects with metabolic syndrome) in one of the basic causes of hypertension which is frequently encountered in these patients. OBJECTIVE: To assess the relations between leptinaemia and the blood pressure reading (actual and mean values) and leptinaemia and the classification of hypertension according to WHO. METHOD: The authors examined 35 hypertensive subject and 10 subject with tetanies (without hypertension). The blood pressure was assessed under standard conditions (rest, semi-recumbent position, three readings). The mean blood pressure readings during the last three months were obtained from case records. Leptin was assessed by the ELISA method of Bio Vendor Co. RESULTS: The group of hypertonic can be classified as subjects with mild obesity (BMI 30.1). The values of leptin were elevated but did not differ significantly from those of the normal population. No correlations were found between leptinaemia (incl. values calculated for BMI) and the actual and mean blood pressure readings. No correlations were found between leptinaemia (incl. BP calculated with regard to BMI) and the stage of hypertension according to WHO. CONCLUSION: Hypertonic subject do not differ significantly as to the serum leptin concentration from the general population. Leptinaemia does not correlate with the actual or mean blood pressure reading nor with stage of hypertension according to the WHO classification. Thus the authors did not confirm the hypothesis on the fundamental effect of leptinaemia on the genesis and development of hypertension. It is probable that leptin is only one of the many factors which have an impact on blood pressure.

Blood Pressure↗
PubMed1999

[Use of proinsulin analysis for estimates of insulin resistance].

INTRODUCTION: According to contemporary estimates diabetes is present in 120 million subjects. This disease is associated with the incidence of a number of very serious organ complications and very frequently is diagnosed late (several years after its development). Because despite increased diagnostic and therapeutic efforts the number of diabetic patients is increasing, new diagnostic and therapeutic means are sought. Evidence was provided that some complications of diabetes develop not only in case of poor compensation but also in hyperinsulinaemia (hypertension, ischaemic heart and coronary artery disease etc.). In clinical practice it is however possible to assess hyperinsulinaemia or incipient insulin resistance only with difficulty because classical examinations (insulin and C-peptide on fasting) have a very low specificity and sensitivity. Therefore for estimation of insulin resistance loading tests are used (e.g. examination of insulin after stimulation with glucose, or C-peptide after stimulation with glucagon, insulin tolerance and suppression tests, or in research projects so-called minimal models or clamp techniques). Any loading test is however demanding from the aspect of time, money, technical aspects and staff and therefore possibilities are sought how to estimate the degree of insulin resistance and sensitivity in a specimen of biological material under basal conditions. OBJECTIVE OF INVESTIGATION: Because in the literature only sporadically assessment of intact proinsulin is mentioned as the ideal marker of insulin resistance under basal conditions, the authors decided to assess the relations between intact proinsulin (PI) and other biochemical parameters in patients with type 2 diabetes and dyslipidaemia (200 probands) and to assess whether PI correlates with the results of loading tests (modified oGTT with calculation of the sum and delta-insulin--120 probands). RESULTS: It was revealed that PI (contrary to insulin, C-peptide and total proinsulin) correlates with the results of the loading test characterizing insulin resistance (sum and delta insulin, correlation coefficient 0.84) (n=120 subjects). It was furthermore found that probands (n=200 subjects) who are followed up on account of type 2 diabetes or dyslipidaemia (or both) differ from the control group (n=20 subjects) as regards biochemical parameters only in the PI concentration (dispensarized patients have higher levels, p>0.99), whereby in other standard basal characteristics of insulin secretion and resistance the groups did not differ. The differences were correlated with HOMA models of insulin secretion and resistance and no correlations were found. The PI concentration in this group correlated significantly with the cholesterol, fibrinogen and triacylglycerol concentration. No relations were found between the values of intact proinsulin with C-peptide and insulin. CONCLUSION: Based on the results of their study the authors assume that examination of intact proinsulin is a valid "basal" indicator of insulin resistance. From the results ensues also that intact proinsulin is probably a very good predictor as regards the risk of development of cardiovascular disease.

Diabetes Mellitus, Type 2↗
PubMed1999

[Leptinaemia in the Czech population].

INTRODUCTION: Leptin is a protein, determined by the ob-gene which influences in a fundamental way the energy metabolism of the organism. A significant effect of leptin on the haematopoietic, immunological and endocrinological system cannot be ruled out nor its effect on the course of pregnancy and maturation of the organism. In humans leptinaemia correlates with the amount of subcutaneous fat which is due to a receptor or post-receptor disorder, obese subjects suffer frequently from hyperleptinaemia. OBJECTIVE: To assess the mean leptinaemia of the general population, seek relations between leptinaemia and anthropological indicators and age. METHODS: Using the method of random sampling the authors examined a group of 538 probands (252 males, 286 females) incl. 12% healthy students of the Faculty of Physical Culture in Olomouc, 37% subjects without acute or chronic complications feeling in good health and 37% patients of the metabolic and diabetological ambulance of the hospital in Sternberk. In each patient a detailed case-history was recorded, an anthropological examination was made and a venous blood sample was taken for leptin analysis (serum, ELISA-sandwich method of BIOVENDOR Co.) RESULTS: Spectrum of patients, whose condition and age distribution in our group corresponded to the general population of the Czech Republic. The mean age of the probands was 51 years (18 to 82 years), the examined group can be characterized as subjects lacking signs of obesity. Leptinaemia was on average about 10 ng/ml (minimum 0, maximum 97.9 ng/ml), whereby men had values round 6 and women round 14 ng/ml (women had also a greater adipose tissue mass). Non-obese subjects (BMI<26) had a mean leptinaemia of 5 (women cca 6, men cca 2 ng/ml), obese subjects (BMI>30) have a leptinaemia of cca 19 ng/ml (women about 26, men about 13 ng/ml). With advancing age the leptinaemia in adults rises up to the age of 70, in subjects above 70 years it does not change (in women it declines significantly). The dynamics of leptinaemia imitate the changes of BMI and percentage of adipose tissue (in men also a rise in WHR). Leptinaemia is associated with the BMI (correlation coefficient 0.55), with the percentage of body fat (correlation coefficient 0.75), and in men with the WHR (correlation coefficient 0.82). The association between ageand leptinaemia is only indicated (correlation coefficient 0.29) and is not very close. According to the authors results subcutaneous body fat is responsible for cca 60% of the variability of leptinaemia (in women as much as 74%), BMI for 23%, age and sex for cca 9% of the vriability of leptinaemia. In men the WHR is responsible for 66% of the variability of leptinaemia. With an increase of subcutaneous adipose tissue by 1% the leptinaemia increases by some 0.54 ng/ml (in men by 0.22 ng/ml, in women by 0.84 ng/ml), with increasing BMI leptinaemia rises by 0.44 ng/ml/u (in men by 1.3 ng/ml, in women by 1.72 ng/ml), with advancing age leptin rises by 0.24 ng/ml/year (in men by 0.16 ng/ml, in women by 0.28 ng/ml), changes of leptinaemia imitate changes of BMI and the percentage of body fat. With increasing WHR in men the leptinaemia rises by 2.6 ng/ml/0.1 WHR. CONCLUSION: Standards of leptinaemia for the general population of the Czech Republic were elaborated. Leptinaemia correlates most closely of all anthropometric indicators with subcutaneous fat and in men with the WHR index. With advancing age between 20 and 70 years leptunaemia rises and then decliunes insignificantly (in women the changes are however significant). The primary cause of the mentioned differencesare probably changes of the bodily constitution.

Adolescent↗
PubMed1998

Is nitric oxide involved in 5-HT3 receptor-mediated neurogenic relaxation of guinea pig proximal colon?

The relaxations mediated by the activation of 5-HT receptors in the guinea pig proximal colon were investigated. Longitudinal strips were cut from the colon segment and placed into the bath. In the presence of atropine (0.2 microM), the relaxations were evoked by adding increasing concentrations of 5-HT (1-100 microM). Noncumulative concentration-response curves were established in the absence and presence of either 5-HT or nitric oxide synthase (NOS) antagonists. Selective 5-HT3 antagonists tropisetron (10 and 100 nM) and ondansetron (1 microM) inhibited the relaxations and shifted the concentration-response curves to the right. Similar effects were observed in the presence of the NOS inhibitor N(G)-nitro-L-arginine (3.2, 10, 32 microM) and partly reversed with L-arginine (100, 320 microM). N(G)-nitro-D-arginine, serving as a negative control, was ineffective. The relaxations were further inhibited in the presence of the soluble guanylate cyclase blocker methylene blue (10 microM) or NO scavenger hemoglobin (32 microM). These results suggest that the 5-HT3 receptor plays a role in neurogenic relaxations of guinea pig proximal colon, which are at least partly mediated via release of NO from nerve endings.

Animals↗
PubMed1998

[Serum leptin, early atherosclerosis and hypolipidemia (a new, previously undescribed effect of pravastatin, a hypolipemic agent)].

Hyperleptinemia is considered to be one of predictors of early atherosklerosis complications. This stimulated us to investigate differences between leptinemia in persons with accelerated atherosclerosis and leptinemia in probands without atherosclerosis complications. The study also verified whether leptinemia and its relationship to other anthropometric and biochemical parameters can differ in hypolipemic-treated probands and hypolipemic-untreated individuals. We examined 89 probands with accelerated atherosclerosis. The controls were 20 persons without any signs of accelerated atherosclerosis. Probands with accelerated atherosclerosis had a slight hyperglycemia and were slightly obese, but they did not meet criteria of metabolic cardiovascular syndrome. No significant differences between both groups under study were found in terms of anthropometric and biochemical parameters (BMI, % body fat, glycemia, insulin, C-peptide, intact proinsulin, total proinsulin cholesterol, HDL, triglycerides, LDL, homeostatic model of insulin secretion and resistance). Leptin concentration was not different as well. Stratification into males and females showed that women had a significantly higher leptinemia and fat tissue mass. Other biochemical parameters were similar in both groups. We suppose that in individuals without signs of metabolic syndrome, leptinemia does not belong among predictors of accelerated atherosclerosis. The accelerated atherosclerosis persons were then divided into subgroups according to medication (28 probands--pravastatin Lipostat 20, 15 probands--phenofibrate Lipanthyl 200M, 9 probands--simvastatin Zocor 20, 47 probands--no hypolipemic medication). No significant differences between the groups were found in terms of the analysed anthropometric and biochemical parameters, except leptinemia. The pravastatin-medicated probands had a significantly lower leptinemia (significant at 99% significance level) which was evidently sex-related than other patients. The pravastatin-administered persons showed no correlation between leptinemia and body fat mass (in contrast to other groups where such a correlation was highly statistically significant). These findings can be explained by a still unclear effect of pravastatin on insulin metabolism and on other factors involved in leptin synthesis and elimination. Thus, a new therapeutic effect of pravastatin can be supposed. This may account for a highly favourable effect of pravastatin on reduced manifestations of atherosclerosis complications event at a low LDL cholesterol decrease (particularly in persons with metabolic cardiovascular syndrome).

Adipose Tissue↗
PubMed1998

[Leptinemia in persons with acute myocardial infarct].

The purpose of the study was to verify whether the currently reported relationship between leptinemia and adipose tissue mass can be applied to cases of acute coronary attack. An increased number of cytokines has been reported in severe acute myocardial infarctions so that correlation between cytokines and leptin was investigated. Correlation between standard coronary markers and leptinemia was also studied. We examined 48 probands, patients of the Coronary Unit, Hospital, Sternberk, who were hospitalized for acute myocardial infarction (AMI--16 probands) or for unstable angina pectoris (UAP--22 probands). The persons with AMI had leptinemia and a higher concentration of interleukine-6 (Il-6) and of cardial troponine-I (cTn-I) than individuals without coronary accident (UAP). Early after the acute coronary lesion, leptinemia in persons with AMI displayed a statistically significant positive correlation with concentration of interleukine-6 and subsequently of markers of coronary lesion severity (cTnI). No correlation between leptinemia and body weight was found in those probands. This study proved that leptinemia in the AMI individuals is influenced directly by concentration of cytokines which leads to leptin superproduction by fat cells and leptin resistance.

Adipose Tissue↗
PubMed1998

[Serum leptin in women during the third trimester of pregnancy].

Leptin is a small protein produced mainly by adipocytes. Recently, its relationship to obesity has been studied extensively. It was proved that obese individuals have either relative or absolute leptin deficiency. Several years ago, leptin was found to be produced also by the placenta. This stimulated us to study relationship between leptinemia and placental hormones in 85 women in the second gravidity trimester. Within the prenatal screening, these pregnant women were subjected to analysis of AFP, hCG, SP-1 glycoprotein and leptin and the results obtained were processed statistically. The control group consisted of 20 nonpregnant women with tetany. Women in the second gravidity trimester were found to have a significantly higher leptinemia than nongravid women (even with respect to body weight). This may be due to a larger amount of adipose tissue during gravidity and also leptin-resistance. Moreover, we recorded a negative correlation between leptinemia related to body weight and concentration of SP-1 glycoprotein. This finding supports the presumption that mother's leptinemia correlated negatively in the second gravidity trimester with quality and quantity of the placental syncytiotrophoblast. Our findings can be explained as follows: the biological effect of leptin is metabolically unfavourable for the growth of the foetus and the placenta. An increased leptinemia with advancing gravidity can be caused by a larger fatty mass and an increased activity of adipocytes when leptin presence increases in system circulation but the organism begins to be leptin-resistant and an "unfavourable" metabolic effect fort the gravid woman and the foetus is not distinct. These findings thus support the hypothesis postulating the nonsignificance of leptin production in human placenta and on the contrary the necessity of leptin-resistance for foetus development from the metabolic point of view. Thus, a decreased leptinemia immediately before and after the delivery could be caused by the still unclear regulators of leptin sensitivity. This is again a metabolically highly favourable state (reduced appetite, decreased body weight, increased energy output and others).

Adipose Tissue↗
PubMed1998

A contribution to the types of branching and anastomoses of the splenic artery in human spleen.

The authors observed in 60 human spleens the course of the splenic artery in the splenic hilus and branching of segmental branches in the spleen. Specimens of blood vessels and casts showed two extreme types of segmental branches entering the splenic parenchyma: 1. Vertical type and 2. subcapsular type. The authors also studied the occurrence of anastomoses between the individual branches of the splenic artery and recognized three types of them: 1. hilar--extraparenchymatous, 2. intraparenchymatous and 3. subcapsular.

Adult↗
PubMed1998

[Leptin, insulin and proinsulin--their relationship].

Leptin is protein produced by mature adipocytes into the system circulation and gives information to hypothalamic centers about fat amount in the organism. Leptin is supposed to play a causal role in energy output of the organism and influences the appetite (antiobese effect). Obese individuals were proved to have frequently hyperleptinemia. This disease is caused by a postreceptor disorder (however, several obese families had also normoleptinemia or even hypoleptinemia which is caused by polymorphism of Ob-gene). It was also found that leptin administration in animals leads to reduced appetite and decreased body weight. Interpretation of leptinemia in human is very complicated because leptinemia is influenced by many independent regulations (hormones, stress, food intake, motor activity atc.). Obesity is often associated with hyperinsulinemia and insulin resistance (a frequent cause of human mortality) so that correlations between insulin and leptin are intensively studied. Experimental models and animal studies revealed the existence of adipoinsular axis and it was found that insulin and leptin are contrahormones. In human studies, the majority of authors did not find correlation between leptinemia and markers of insulin secretion. Similar conclusions were drawn out in our previous paper [118]. This may be due to complex regulations of leptinemia in the organism and the use of biochemical markers with limited validity (insulin, C-peptide in fasting state and after stimulation). Therefore we decided to study correlation between leptinemia and intact proinsulin in the serum which is now considered to be the most valid marker of insulin secretion and provides information about an average "daily" insulinemia. This study was stimulated by the fact that increased leptinemia is found also in persons with prolonged hyperinsulinemia (a short-term hyperinsulinemia does not affect leptin concentration so that no available marker of insulin secretion is valid). We examined the group of 31 probands, patients of the Metabolic and Diabetologic Center at the hospital in Sternberk. They were diabetic patients of type 2 who were treated by peroral antidiabetics and insulin and who met criteria of good compensation. However, no correlation between leptinemia and proinsulinemia was found. We suppose that this failure was due to complicated fine regulations affecting leptinemia and also to the fact that intact proinsulin is not an "ideal" marker of a long-term hyperinsulinemia (correlation between insulin and leptin at euglycemic clamp indicates that there exist correlation between these parameters in human).

Adipose Tissue↗
PubMed1997

[Leptin in persons with simple obesity].

Obesity is a disease with distinct genetic determination and its phenotype is defined by the still unknown number of genes whose expression can be influenced by environmental factors. Several years ago, "obesity gene" was isolated in animals. This gene, coding protein which consists of 165 amino acids, is called leptin. Leptin is supposed to be a key substance controlling homeostasis of body weight and energy balance; it is produced by adipocytes and its value correlates highly significantly with anthropometric parameters that characterize physical constitution and amount of subcutaneous fatty tissue. The obese individuals often display hyperleptinemia which is frequently caused by a postreceptor disorder; sporadically, a different leptin structure or hypoleptinemia (caused by genetic anomaly) are reported. It is supposed that either absolute or relative leptin deficiency in obese persons are associated with causal obesity (e.g. appetite stimulation). Leptinemia values correlate with percentage of subcutaneous fatty tissue, insulinemia and sometimes with glycemia. In our study we examined 200 probands, patients of the Metabolic and Diabetologic Out-Patient Department, Hospital in Sternberk. A very close correlation between the amount of subcutaneous fatty tissue (measured by a caliper in 10 skinfolds) and the leptine serum concentration was found. The values of leptinemia in men of normal constitution ranged within 1-11 ng/ml, non-obese women had 3-4 times higher values. Leptinemia in some obese individuals reached up to 70 ng/ml. However, the currently calculated and reported parameters of physical constitution (BMI, WHR, Grant index) did not correlate significantly with leptinemia. Similarly, biochemical parameters considered as general markers of insulin resistance (often associated with obesity) did not correlate significantly with leptinemia. This finding indicates that some calculated parameters, quantifying and gualifying physical constitution, may be ambiguous and leptinemia was found to give more detailed information about the amount of subcutaneous fatty tissue than WHR or BMI. An accidental finding was an important positive correlation between myoglobin concentration and creatinemia. At monitoring the effect of hypolipidemic agents we use the myoglobin examination and therefore we consider this correlation to be very important and every physician performing this analysis should be informed about it. The present study thus confirmed that a more accurate quantification of subcutaneous fatty tissue is required. On the other hand, we believe that examination of leptinemia can contribute significantly to stratification of patients into risk groups (with respect to clinical, economic and time differentiation) and subsequently to the treatment of these patients. In future, criteria for quantification of leptinemia and leptine resistance should be defined precisely.

Adipose Tissue↗