Biomedical subjects

F Novák

Publications and source records attributed to F Novák.

At least 19 recordsLinked to original sources

PubMed2005

[Risk of malnutrition and the role of artificial nourishment].

Malnutrition represents a serious risk factor, which can bring about prolongation of the hospitalization, higher incidence of complications and higher mortality. Such relation is well documented in several epidemiologic studies. The treatment of malnutrition, though large progress has been reached in the treatment, forms and indications of enteral and parenteral artificial nourishment, is based first of all on the elimination of the original cause, i.e. in the treatment of the primary disease. Nevertheless the role of artificial nourishment is irreplaceable. It serves as a supportive therapy namely to overcome the period till the alimentation per os is restituted. In other cases, when the normal alimentation route is not possible to restitute in sufficient extent, the parenteral or enteral artificial nourishment remain the permanent necessity and the life rescuing treatment.

Humans↗

PubMed2005

[Changes in leptin, leptin receptor and fatty acids levels during chemoradiotherapy for oesophageal cancer].

BACKGROUND: Oesophageal cancer patients with substantial weight loss have worse prognosis. Weight loss is often refractory to the nutritional support. Causes of the weight loss are multiple: oesophageal stricture, frequent alcohol abuse, cancer related cachexia. It may be a consequence of metabolic changes mediated by cytokines, hormones and tumour derived products. Leptin, a protein produced by adipocytes, is an important signalling molecule in energy regulation, metabolism of fatty acids and it can also augment tumour growth of various cancer cell lines. Enhanced intake of poly-unsaturated fatty acids may play an important role in the reversal of cancer related weight loss. METHODS AND RESULTS: In this study we examined the nutritional status (pre-treatment weight-loss, actual weight, body mass index), serum levels of leptin, soluble leptin receptor, TNF-alpha, IGF-1 and plasma phosphatidyl-cholin fatty acids before the beginning of treatment, after the onset of treatment and shortly before its completion. In the group of 38 pts (33 men, 5 women), mean age 58 years, statistically significant mean pre-treatment weight-loss 8 kg and significant mean weight loss 2 kg after chemoradiotherapy was observed. Concomitant chemoradiation led to transient elevation of serum leptin level despite the weight loss during chemoradiotherapy. Significant changes in the distribution of fatty acids in plasmatic phosphatidyl-cholin were observed. CONCLUSIONS: Our results show the possibility for direct influence of chemoradiotherapy on body weight regulation in advanced oesophageal cancer patients.

Adult↗

PubMed2004

Composition of plasma fatty acids and non-cholesterol sterols in anorexia nervosa.

Anorexia nervosa is a model of simple starvation accompanied by secondary hyperlipoproteinemia. The pattern of plasma fatty acids influences the levels of plasma lipids and lipoproteins. The concentration of plasma lathosterol is a surrogate marker of cholesterol synthesis de novo, concentrations of campesterol and beta-sitosterol reflect resorption of exogenous cholesterol. The aim of the study was to evaluate fatty acids in plasma lipid classes and their relationship to plasma lipids, lipoproteins, cholesterol precursors and plant sterols. We examined 16 women with anorexia nervosa and 25 healthy ones. Patients with anorexia nervosa revealed increased concentrations of total cholesterol, triglycerides, HDL-cholesterol, campesterol and beta-sitosterol. Moreover, a decreased content of n-6 polyunsaturated fatty acids was found in all lipid classes. These changes were compensated by an increased content of monounsaturated fatty acids in cholesteryl esters, saturated fatty acids in triglycerides and both monounsaturated and saturated fatty acids in phosphatidylcholine. The most consistent finding in the fatty acid pattern concerned a decreased content of linoleic acid and a raised content of palmitoleic acid in all lipid classes. The changes of plasma lipids and lipoproteins in anorexia nervosa are the result of complex mechanisms including decreased catabolism of triglyceride-rich lipoproteins, normal rate of cholesterol synthesis and increased resorption of exogenous cholesterol.

Adult↗

PubMed2004

Effect of Chalara longipes on decomposition of humic acids from Picea abies needle litter.

The effect of the saprotrophic ascomycete Chalara longipes on the decomposition of humic acids was determined in a cultivation experiment. The fungus was incubated in liquid cultures in a full-strength (F system) and an organic nitrogen-free medium (F-N system), both amended with pure humic acids isolated from spruce forest litter. Fungal biomass production was highest in the F system with humic acids and lowest in the F-N system, the effect of organic nitrogen and humic acids being significant (p < 0.05). The presence of organic nitrogen seems to be essential for growth. The fungus utilized humic acids; molar mass distribution in media obtained by gel-permeation chromatography showed decrease in the humic acids fraction. Decolorization of the media reached 75 and 64 % in the F and F-N systems, respectively. The molar mass of humic acids probably also decreased as estimated from the increase in the absorbance A465/A665 (A4/A6) ratio. It is assumed that the utilization of humic acids may be mediated by the production of organic acids (as their components) and production of some oxidative enzymes.

Ascomycota↗

PubMed2004

[Vasopressin and its analogues in the therapy of shock].

Hemodynamic support during the circulatory failure with vasodilation, most frequently during the septic shock, is based on volume recovery and administration of inotropic drugs. If such therapy is not sufficient, vasoconstriction drugs are subsequently or parallel added to maintain the perfusion pressure. As a standard therapy, norepinephrine or other catecholamines with alpha-adrenergic effect are used in rising doses. Some patients do not respond to such therapy with desired hemodynamic changes--they develop catecholamine resistant shock. Because of serious side effects of high doses of catecholamines, alternative vasopressors are necessary. Vasopressin, antidiuretic hormone, has in physiological conditions only minimal effect of the vascular tone. During hypovolemia its concentration rises and it may significantly contribute to the maintenance of arterial pressure by vasoconstriction. Contrary to it, during septic shock the levels of vasopressine are very low and vasodilation clinically dominates. At the same time, the septic shock is accompanied by an increased sensitivity to vasopressin administration. In a critical shock a serious deficit of endogenous vasopressin is expected. At present several pilot studies with vasopressine administration in septic shock exist in literature describing beneficial effect of vasopressin on hemodynamic parameters. Such comparatively low doses have no side effects on perfusion and function of body organs. Terlipressin, which is available in Czech Republic, is a synthetic analogue of vasopressin with extended effect. Its intermittent administration is used for the treatment of portal hypertension complications. Terlipressin in animal model of septic shock has similarly beneficial effects as vasopressin. High doses of Terlipressin have, similarly to vasopressin, adverse effects on pulmonary circulation and other systems. Till present, only casuistic experience has been published with low doses of Terlipressin in the treatment of septic shock resistant to catecholamines, which has shown similar effects to vasopressin. In shock states with the deficit of endogenous vasopressin, which are resistant to high doses of catecholamines, administration of vasopressin analogues represents a new perspective therapy. The treatment should be studied from the point of morbidity and mortality. A careful approach has to be used in septic patients with pre-existing obliterative vassal disease.

Animals↗

PubMed2004

[Acute liver failure related to the syndrome of exertional heatstroke].

Heatstroke syndrome is a well-described state, which usually occurs in areas with warm climates. Two forms are commonly distinguished: the exertional and the classic heatstroke. Increased serum levels of liver enzymes are often detected in this condition. However, acute hepatic failure following exertional heatstroke is rare. We report a case of a 30 years old man with exertional heatstroke, acute hepatic failure, serious coagulation impairment and a rhabdomyolysis following ten kilometers run. Acute hepatic failure completely developed the forth day of hospitalisation. On the fifth day, the patient fulfilled London criteria for liver transplantation and was referred to the transplantation center for the optimal management assessment. After the conservative management of acute phase, spontaneous recovery of liver functions occurred and the patient finally was not transplanted. 23 days after admission to the hospital, the patient was discharged with residual cholestasis and was followed up on outpatient basis. Serum levels of liver enzyme returned to the normal 3 months after the liver injury. In several cases, the liver failure following heatstroke is reversible and conservative management can be successful. Additionally, in 3 reported cases, emergency liver transplantation for acute hepatic failure due to heatstroke with renal failure and coma showed very poor outcome. Our case demonstrates that conservative management even in patients fulfilling accepted criteria for emergency liver transplantation can be effective and should be considered in similar condition.

Adult↗

PubMed2004

Phospholipid composition of myocardium in children with normoxemic and hypoxemic congenital heart diseases.

Samples of myocardial tissue were obtained during cardiac surgery from children operated for different types of normoxemic and hypoxemic congenital heart diseases. The phospholipid composition was analyzed by thin layer chromatography. The concentration of total phospholipids (PL), phosphatidylcholine and phosphatidylethanolamine (PE) was found lower in atrial tissue of both normoxemic and hypoxemic groups in comparison with the ventricles. When comparing the difference between hypoxemic and normoxemic defects, hypoxemia was found to increase the concentration of total PL, PE and phosphatidylserine in ventricles and total PL and PE in the atria. The increased level of particular phospholipid species may represent adaptive mechanisms to hypoxemia in children with congenital heart diseases.

Child↗

PubMed2004

[Diagnostics and treatment of ventilator-associated bronchopneumonia at a coronary unit].

Ventilator-associated pneumonia represents a severe complication in patients who are receiving mechanical ventilation. The incidence is presumed to be 25% of the total number of mechanically ventilated patients. The clinical assessment is usually based on the presence of a new radiographic infiltrate, fever, blood leukocytosis, or leukopenia and purulent tracheal secretions. According to the time after tracheal intubation when VAP occurs we can distinguish early and late onset VAP, which differs in terms of infectious agent. The early and adequate antibiotic therapy together with the basic preventive treatment represents the only possibility to avoid the complications. The article reviews the actual knowledge of this phenomenon, the adequate diagnostic attitudes and therapeutic possibilities.

Bronchopneumonia↗

PubMed2003

Corticosteroid effect on Caco-2 cell lipids depends on cell differentiation.

Previous studies from our laboratory have indicated that secondary hyperaldosteronism affects phospholipids of rat colonic enterocytes. To assess whether this represents a direct effect of mineralocorticoids on enterocytes, the role of aldosterone and dexamethasone in the regulation of lipid metabolism was examined in Caco-2 cells during development of their enterocyte phenotype. Differentiation of Caco-2 cells was associated with increased levels of triglycerides (TG) and cholesteryl esters (CE), a decreased content of cholesterol and phospholipids and changes in individual phospholipid classes. The phospholipids of differentiated cells had a higher content of n-6 polyunsaturated fatty acids (PUFA) and lower amounts of monounsaturated (MUFA) and saturated fatty acids than subconfluent undifferentiated cells. Differentiated cells exhibited a higher ability to incorporate [3H]arachidonic acid (AA) into cellular phospholipids and a lower ability for incorporation into TG and CE. Incubation of subconfluent undifferentiated cells with aldosterone or dexamethasone was without effect on the content of lipids, their fatty acids and [3H]AA incorporation. In contrast, aldosterone treatment of differentiated cells diminished the content of TG, increased the content of phospholipids and modulated their fatty acid composition. The percentage of n-6 and n-3 PUFA in phospholipids was increased and that of MUFA decreased, whereas no changes in TG were observed. The incorporation of [3H]AA into phospholipids was increased and into TG decreased and these changes were blocked by spironolactone. Treatment of differentiated cells with dexamethasone increased their CE content but no effect was identified upon other lipids, their fatty acid composition and on the incorporation of [3H]AA. As expected for the involvement of corticosteroid hormones the mineralocorticoid and glucocorticoid receptors were identified in Caco-2 cells by RT-PCR. The results suggest that aldosterone had a profound influence on lipid metabolism in enterocytes and that its effect depends on the stage of differentiation. The aldosterone-dependent changes occurring in phospholipids and their fatty acid composition may reflect a physiologically important phenomenon with long-term consequences for membrane structure and function.

Aldosterone↗

PubMed2003

[Lipid metabolism in anorexia nervosa].

BACKGROUND: Anorexia nervosa is a model of simple starvation accompanied by secondary hyperlipoproteinemia. Plasma fatty acid pattern influences levels of plasma lipids and lipoproteins. Level of plasma lathosterol represents a marker of cholesterol synthesis de novo; levels of plant sterols reflect resorption of exogenous cholesterol. The aim of the study was to evaluate fatty acids in plasma lipid classes and their relationships to plasma lipids, lipoproteins, lathosterol, campesterol and beta-sitosterol. METHODS AND RESULTS: We examined 16 women with anorexia nervosa and 25 matched controls. Main lipid classes were separated by thin-layer chromatography, fatty acids and non-cholesterol sterols were evaluated by capillary gas chromatography. Patients with anorexia nervosa revealed increased concentrations of total cholesterol, triglycerides, HDL-cholesterol, campesterol and beta-sitosterol; changes in plasma levels of lathosterol did not reach statistical significance. The most consistent finding in fatty acid composition was a decreased content of linoleic acid and raised content of palmitoleic acid in all lipid classes. CONCLUSIONS: Changes of plasma lipids and lipoproteins in anorexia nervosa result from complex mechanisms including increased synthesis of triglyceride-rich lipoproteins along with unchanged cholesterol synthesis rate. Hypercholesterolemia in anorexia nervosa may also result from increased resorption of exogenous cholesterol.

Adult↗

PubMed2001

[Metabolic disorders in nonspecific inflammatory bowel diseases].

The primary function of the gastrointestinal system is to assist the intake and further processing of food and liquids. Besides that, it forms an anatomical barrier between the external environment and internal milieu. It is also highly important for its paracrine and endocrine function. Inflammatory bowel diseases, which frequently cause a gastrointestinal failure, form a specific group. Most frequently it is the ulcerative colitis and Crohn's disease. Impaired integrity of the gastrointestinal mucosa and failure of protective mechanisms lead to the increased permeability of the intestinal wall for antigens derived from food, saprophytic bacteria and pathogenic microorganisms. When the gastrointestinal failure is threatening, factors determining its residual function become more important. As decisive reveals the severity and location of the primary disease. Previous surgeries and adaptation of the residual part of the gastrointestinal system are important, as well as the possibility of peroral or enteral nutrient intake. Depending on the presence of risk factors and the degree of residual gut function, some complications can be expected: dehydration, mineral disorders, symptoms of protein and energy depletion, infection, and multiple organ dysfunction syndrome. It is highly important to decide whether the gastrointestinal system will be included into or excluded from the process of realimentation. Critically ill patients with inflammatory bowel diseases should be treated at an intensive care unit.

Deficiency Diseases↗

PubMed2001

[Weaning from artificial pulmonary ventilation].

Weaning from mechanical ventilation is not complicated in the majority of patients, in some, however, this process is very complicated and lengthy. These patients are described as difficult to wean. A suitable weaning strategy and properly timed extubation or decannulation is important not only from the aspect of the patient's health status but also with regard to costs of care. When selecting patients suitable for weaning it is useful to use prognostic indicators of success. The Tobin-Yang index and ratio Pa O2/FiO2 seem to be most useful. Based on available information it seems that the pressure support and weaning by means of T-piece is more effective than weaning using the SIMV regime. Promising seems the use of non-invasive ventilation but this was not proved unequivocally so far. The use of weaning protocols reduces the weaning period from mechanical ventilation. The authors summarize most recent findings on the weaning problem incl. the most frequently used ventilation regimes and prognostic indicators of successful weaning.

Humans↗

PubMed2000

Aldosterone alters the phospholipid composition of rat colonocytes.

Previous studies have shown that aldosterone treatment of amphibian epithelial cells results not only in stimulation of Na(+) absorption but also in changes in phospholipid composition which are necessary for the mineralocorticoid action of aldosterone. The present study was designed to investigate the effect of aldosterone on phospholipids of mammalian epithelia. Phospholipid and fatty acid composition was examined in colonic epithelium (mineralocorticoid target tissue) and thymus (non-mineralocorticoid but glucocorticoid target tissue) of rats which had received aldosterone or vehicle by a miniosmotic pump for 7 days. Aldosterone increased the mass of colonic phospholipids relative to cellular proteins with concomitant changes in the percentage distribution of fatty acids, whereas the relative distribution of membrane phospholipds was not changed. Phosphatidylcholine increased the content of polyunsaturated and decreased that of monounsaturated fatty acids, which predominantly reflected the accretion of arachidonic and a decrease in oleic and palmitoleic acids. Within the phosphatidylethanolamine subclass, pretreatment of rats with aldosterone decreased the content of monounsaturated fatty acids (predominantly oleic and palmitoleic acid) and of n-3 fatty acids, and increased the content of saturated fatty acids (palmitic acid). The saturated-to-nonsaturated fatty acid ratio also significantly increased after aldosterone treatment. No changes in thymic phospholipids were seen. The results are consistent with the contention that aldosterone specifically modulates phospholipid concentration and metabolism in mineralocorticoid target tissue. The changes in phospholipid content and its fatty acid composition during the fully developed effect of aldosterone may reflect a physiologically important phenomenon with long-term consequences for membrane structure and function.

Aldosterone↗

PubMed2000

Low-salt diet alters the phospholipid composition of rat colonocytes.

The effect of low-salt diet on phospholipid composition and remodeling was examined in rat colon which represents a mineralocorticoid target tissue. To elucidate this question, male Wistar rats were fed a low-salt diet and drank distilled water (LS, low-salt group) or saline instead of water (HS, high-salt group) for 12 days before the phospholipid concentration and fatty acid composition of isolated colonocytes were examined. The dietary regimens significantly influenced the plasma concentration of aldosterone which was high in LS group and almost zero in HS group. Plasma concentration of corticosterone was unchanged. When expressed in terms of cellular protein content, a significantly higher concentration of phospholipids was found in LS group, with the exception of sphingomyelin (SM) and phosphatidylserine (PS). Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) accounted for more than 70% of total phospholipids in both groups. A comparison of phospholipid distribution in LS and HS groups demonstrated a higher percentage of PE and a small, but significant, decrease of PC and SM in LS group. The percentage of phosphatidylinositol (PI), PS and cardiolipin (CL) were not affected by mineralocorticoid treatment. With respect to the major phospholipids (PE, PC), a higher level of n-6 polyunsaturated fatty acids (PUFA) and lower levels of monounsaturated fatty acids were detected in PC of LS group. The increase of PUFA predominantly reflected an increase in arachidonic acid by 53%. In comparison to the HS group, oleic acid content was decreased in PC and PE isolated from colonocytes of the LS group. Our data indicate that alterations in phospholipid concentration and metabolism can be detected in rats with secondary hyperaldosteronism. The changes in phospholipid concentration and their fatty acid composition during fully developed effect of low dietary Na+ intake may reflect a physiologically important phenomenon with long-term consequences for membrane structure and function.

Aldosterone↗

PubMed1996

Phospholipid composition in the rat heart exposed to pressure overload from birth.

A pressure overload was induced in 2-day-old male rats by abdominal aortic constriction, and the phospholipid composition of the left ventricle (LV) and the right ventricle (RV) were determined. Sixty days after the surgery, body weights was lower and LV weight were higher in aorta-constricted (AC) rats in comparison with shamoperated animals. Increased ventricular/body weight ratios indicated a significant degree of hypertrophy of LV and smaller hypertrophy of RV. The concentrations of total phospholipids (PL), choline phosphoglycerides (PC), ethanolamine phosphoglycerides (PE), diphosphatidylglycerol (DPG) and phosphatidylinositol (PI) were decreased in both ventricles of AC rats. The concentrations of sphingomyelin (SM) and plasmalogen PE (PLPE) increased in LV only. The changes in phospholipid composition in the developing pressure-overloaded myocardium may contribute to altered membrane functions connected with heart hypertrophy.

Animals↗

PubMed1994

Regulation of phospholipid degradation and biosynthesis in the heart by isoprenaline: effect of mepacrine.

We investigated the effect of isoprenaline (IPRO), a beta-mimetic catecholamine, on incorporation (32P)Pi into phospholipids of the mouse left ventricle in vivo. All experimental groups of male mice received an injection of (32P)Pi (250 MBq x kg-1 b.w.) intraperitoneally two hours prior to sacrifice. A single dose of IPRO (5 mg x kg-1 b.w.) was injected one hour before killing. IPRO increased the specific radioactivity of phosphatidylcholine (PC) by a factor of 1.8, diphosphatidylglycerol (DPG) 2.1, sphingomyelin (SM) 3.5, phosphatidylinositol (PI) 1.7, phosphatidylserine (PS) 1.7, phosphatidylglycerol (PG) 1.7, phosphatidic acid (PA) 2.0 compared to control values. On the other hand, IPRO is also known to stimulate phospholipid degradation by activation of phospholipase A2. That is why we used mepacrine (50 mg x kg-1 b.w.), a phospholipase inhibitor, to find a possible link between biosynthesis and degradation of phospholipids. Pretreatment with mepacrine two hours prior to sacrifice suppressed IPRO stimulated incorporation of (32P)Pi into phospholipids nearly to control levels. Mepacrine itself did not significantly influence the specific radioactivity of phospholipids. We conclude that phospholipase A2 inhibitor, mepacrine, is able to prevent IPRO-stimulated incorporation into phospholipids, suggesting a feedback relation between their biosynthesis and degradation in the myocardium.

Animals↗

PubMed1990

An experimental immunoscintigraphic study with anti-CEA monoclonal antibody (DG2).

Monoclonal antibody D11-DG2 (DG2) against carcinoembryonic antigen (CEA) was examined for suitability for radioimmunodetection of human tumors grown in nude mice. Antibodies DG2 and a control antibody of the same IgG1 subclass were labeled with 131I and injected into mice bearing one of three types of CEA-containing tumors (cell lines LS 174T, HT-29 and Rec S) and/or a CEA-negative tumor (Rec R). Gamma-camera imaging and distribution studies revealed that CEA-containing tumors selectively accumulate DG2 but Rec R does not. As the tumors differ in CEA-content, the highest accumulation of 131I-DG2 (corresponding to the best scintigraphic imaging) was found in LS 174T tumors, intermediate in Rec S and lowest in HT-29 tumors. The mean tumor-to-blood ratios on the sixth day after antibody administration were 4.6, 3.2, and 2.1, respectively, in the control experiments the value of this parameter was always lower than 1. The results showed the applicability of DG2 for immunoscintigraphic studies in patients. Furthermore, a positive correlation was found between the uptake of anti-CEA antibody and CEA-content in the tumors.

Animals↗

PubMed1989

[Immunoscintigraphy in experiments and clinical practice: its possibilities, advantages and limitations].

The authors present their experience gained in preparing, isolating and labeling antibodies with radionuclides for the purpose of using them in immunoscintigraphy. The experimental part includes results obtained with different labeled antibodies and their F/ab/2 fragments in distribution studies, involving also immunoscintigraphic imaging of tumors. The clinical part presents results of immunoscintigraphy obtained with the commercial antibody kits Iodomab and Imacis in patients with tumors of the digestive tract.

Animals↗