In this review we present immunohistochemical methods for visualization of capillaries and muscle fibres in thick muscle sections. Special attention is paid to the procedures that preserve good morphology. Applying confocal microscopy and virtual 3D stereological grids, or tracing of capillaries in virtual reality, length of capillaries within a muscle volume or length of capillaries adjacent to a muscle fibre per fibre length, fibre surface area or fibre volume can be evaluated by an unbiased approach. Moreover, 3D models of capillaries and muscle fibres can be produced. Comparison of the developed methods with counting capillary profiles from 2D sections is discussed and the reader is warned that counting capillary profiles from 2D sections can underestimate the capillary length by as much as 75 percent. Application of the described 3D methodology is illustrated by the anatomical remodelling of capillarity during acute denervation and early reinnervation in the ra t soleus and extensor digitorum longus muscles., I. Eržen, J. Janáček, L. Kubínová., and Obsahuje bibliografii a bibliografické odkazy
Nitric oxide (NO) plays a crucial role not only in regulation of blood pressure but also in maintenance of cardiac autonomic tone and its deficiency induced hypertension is accompanied by cardiac autonomic dysfunction. However, underlying mechanisms are not clearly defined. We hypothesized that sympathetic activation mediates hemodynamic and cardiac autonomic changes consequent to deficient NO synthesis. We used chemical sympathectomy by 6-hydroxydopamine to examine the influence of sympathetic innervation on baroreflex sensitivity (BRS) and heart rate variability (HRV) of chronic NG-nitro-L-arginine methyl ester (L-NAME) treated adult Wistar rats. BRS was determined from heart rate responses to changes in systolic arterial pressure achieved by intravenous administration of phenylephrine and sodium nitroprusside. Time and frequency domain measures of HRV were calculated from 5-min electrocardiogram recordings. Chronic L-NAME administration (50 mg/kg per day for 7 days orally through gavage) in control rats produced significant elevation of blood pressure, tachycardia, attenuation of BRS for bradycardia and tachycardia reflex and fall in time as well as frequency domain parameters of HRV. Sympathectomy completely abolished the pressor as well as tachycardic effect of chronic L-NAME. In addition, BRS and HRV improved after removal of sympathetic influence in chronic L-NAME treated rats. These results support the concept that an exaggerated sympathetic activity is the principal mechanism of chronic L-NAME hypertension and associated autonomic dysfunction., M. Chaswal, S. Das, J. Prasad, A. Katyal, M. Fahim., and Obsahuje bibliografii
The resting membrane potential (Vm) of isolated somatic longitudinal muscles of the earthworm Lumbricus terrestris was studied by glass microelectrodes. The inhibition of chloride permeability by low pH did not affect Vm of the muscle fibers in isolated somatic longitudinal muscles of the earthworm Lumbricus terrestris which was -48.7 mV (inside negative) at pH 7.3 and -49.1 at pH 5.6. On the other hand, bathing the muscles in Cl- and Na+-free solutions, or application of the chloride transporter inhibitor furosemide and Na+-K+-ATPase inhibitor ouabain depolarized the Vm by 3-5 mV. The effects of a Cl- -free solution and ouabain were not additive. This demonstrates relatively small contribution of equilibrium potential for Cl- to the resting membrane potential and electrogenic effect of Na+K+-ATPase which is dependent on the supply of Na+i ions by furosemide-sensitive and Cl-e- and Na+e-dependent electroneutral transport (most probably Na+K+Cl- cotransport)., E. M. Volkov, L. F. Nurullin, E. Nikolsky, J. Krůšek, F. Vyskočil., and Obsahuje bibliografii
The basis for most acute coronary events is either rupture or fissuring of unstable atherosclerotic plaques with subsequent thrombosis leading to coronary artery occlusion. The development of atherosclerotic plaques takes several decades, but the mechanical features determining its stability and the risk of rupture can change very rapidly depending on a number of internal factors. Unstable plaques have a large lipid core, a thin overlying fibrous cap and an abundance of inflammatory cells. The most important factor determining the plaque stability is the plasma level of atherogenic LDL particles. Increased levels of these particles cause endothelial dysfunction with impaired vasodilatation capacity and prevalence of vasoconstriction, maintain inflammatory infiltration of the plaque, impair the strength of the fibrous cap and facilitate aggregation and coagulation. Effective lowering of plasma cholesterol by pharmacological and non-pharmacological means can revert most of these processes and increase the plaque's mechanical stability within several hours to days. Lipid lowering therapy can therefore decrease the risk of acute coronary events within a very short space of time. Thus a radical decrease in lipid levels, along with modification of other risk factors, may become the cornerstone for treatment of acute coronary syndromes, in addition to being an effective treatment in primary and secondary prevention of coronary heart disease (CHD)., T. Štulc, R. Češka., and Obsahuje bibliografii
The aim of the present study was to investigate whether enzyme chondroitinase ABC (ChABC) treatment influences the phenotype of neural progenitor cells (NPCs) derived from injured rat spinal cord. Adult as well as fetal spinal cords contain a pool of endogenous neural progenitors cells, which play a key role in the neuroregenerative processes follow ing spinal cord injury (SCI) and hold particular promise for therapeutic approaches in CNS injury or neurodegenerative diso rders. In our study we used in vitro model to demonstrate the differentiation potential of NPCs isolated from adult rat spinal cord after SCI, treated with ChABC. The intrathecal delivery of ChABC (10 U/ml) was performed at day 1 and 2 after SCI. The present findings indicate that the impact of SCI resulted in a decrease of all NPCs phenotypes and the ChABC treatment, on the contra ry, caused an opposite effect., L. Slovinská, I. Novotná, D. Čížková., and Obsahuje bibliografii a bibliografické odkazy
The function of chromogranin A (CGA) is reviewed, and the radioimmunometric determination of plasma CGA was evaluated as a marker of pheochromocytoma using a comparison of pheochromocytoma patients immediately before surgery (group P, n=25, 635±451 ng/ml) with other groups of patients, i.e. pheochromocytoma patients approximately 1 year after removal of tumor (group PP, n=13, 69±33 ng/ml), medullary thyroid carcinoma patients (group M, n=22, 106±59 ng/ml), congenital adrenal hyperplasy patients (n=33, 65±40 ng/ml), and controls (n=31, 66±29 ng/ml). A CGA level above cut off value 130 ng/ml was found in 24 of 25 patients in group P, 1 (relapse) of 13 patients in group PP, and 4 of 22 patients in group M. In the group P we found a significant association between the size of the tumors removed and plasma CGA concentrations (p=0.0016), and also a significant (p=0.0016) relationship between plasma CGA concentrations and PASS score rating the malignity of pheochromocytoma. We can conclude that plasma CGA concentration as determined by radioimmunometric assay (which is simple without the necessity of special laboratory equipment) is an effective marker of pheochromocytoma with association to malignity and tumor mass., R. Bílek, L. Šafařík, V. Ciprová, P. Vlček, L. Lisá., and Obsahuje bibliografii a bibliografické odkazy
We aimed to compare the effects of chronic and acute administration of structurally different antihypertensives, diuretics - indapamide and hydrochlorothiazide, ACE inhibitor - captopril and indapamide+captopril combination on endothelium-dependent relaxation of femoral artery isolated from nitric oxide (NO)-deficient rats. In the chronic experiment, femoral artery was isolated from Wistar rats receiving L-NAME (40 mg/kg/day) solely or with indapamide (1 mg/kg/day), hydrochlorothiazide (10 mg/kg/day), captopril (10 mg/kg/day), and indapamide+captopril combination for seven weeks. In the acute in vitro experiment, the incubation medium with femoral artery isolated from L-NAMEhypertensive rats was supplemented with investigated antihypertensives in the same concentration 10-4 mol/l. Interestingly, chronic L-NAME treatment did not cause a reduction of vasorelaxation. Indapamide+captopril elevated relaxation above the control level and completely prevented blood pressure increase induced by L-NAME. Acute incubation with captopril only or indapamide+captopril improved relaxation of femoral artery isolated from L-NAMEhypertensive rats, while the incubation with all antihypertensives increased vasorelaxation of femoral artery isolated from control Wistar rats. In conclusion, NO might be involved in the indapamide- and hydrochlorothiazide-induced improvement of vasorelaxation, while different vasorelaxing factors (prostacyclin, EDHF) contribute to the captoprilinduced improvement of vasorelaxation. During the chronic treatment additive and synergic effects of indapamide and captopril may contribute to the prevention of hypertension and increase of vasorelaxation., M. Sládková, S. Kojšová, L. Jendeková, O. Pecháňová., and Obsahuje bibliografii
a1_Chronic smoking alters the circulating levels of sex hormones and possibly also the neuroactive steroids. However, the data available is limited. Therefore, a broad spectrum of free and conjugated steroids and related substances was quantified by GC-MS and RIA in premenopausal smokers and in age-matched (38.9±7.3 years of age) non-smokers in the follicular (FP) and luteal phases (LP) of menstrual cycle (10 non-smokers and 10 smokers, in the FP, and 10 non-smokers and 8 smokers in the LP). Smokers in both phases of the menstrual cycle showed higher levels of conjugated 17-hydroxypregnenolone, 5α-dihydroprogesterone, conjugated isopregnanolone, conjugated 5α-pregnane-3β,20α-diol, conjugated androstenediol, androstenedione, testosterone, free testosterone, conjugated 5α-androstane-3α/β,17β-diols, and higher free testosterone index. In the FP, the smokers exhibited higher levels of conjugated pregnenolone, progesterone, conjugated pregnanolone, lutropin, and a higher lutropin/follitropin ratio, but lower levels of cortisol, allopregnanolone, and pregnanolone. In the LP, the smokers exhibited higher levels of free and conjugated 20α-dihydropregnenolone, free and conjugated dehydroepiandrosterone, free androstenediol, 5α-dihydrotestosterone, free and conjugated androsterone, free and conjugated epiandrosterone, free and conjugated etiocholanolone, 7α/β-hydroxy-dehydroepiandrosterone isomers, and follitropin but lower levels of estradiol and sex hormone binding globulin (SHBG) and lower values of the lutropin/follitropin ratio. In conclusion, chronic cigarette smoking augments serum androgens and their 5α/β-reduced metabolites (including GABAergic substances) but suppresses the levels of estradiol in the LP and SHBG and may induce hyperandrogenism in female smokers., a2_The female smokers had pronouncedly increased serum progestogens but paradoxically suppressed levels of their GABA-ergic metabolites. Further investigation is needed concerning these effects., M. Dušková ... [et al.]., and Obsahuje seznam literatury
The mechanisms and myocardial alterations associated with NO-deficient hypertension are still far from clear. The aim of the present study was to focus on the enzyme histochemical and subcellular changes in the heart of L-NAME treated rats, as well as to examine the influence of captopril treatment. Wistar rats were administered either L-NAME (40 mg/kg/day) alone or together with captopril (100 mg/kg/day) for a period of 4 weeks. A significant increase of blood pressure confirmed the reliability of the model. The results showed that long-lasting L-NAME administration was accompanied by a decrease of endothelial NO-synthase activity and by a significant local decrease of the following enzyme activities: capillary-related alkaline phosphatase, 5’-nucleotidase and ATPase (but not dipeptidyl peptidase IV) and cardiomyocyte-related glycogen phosphorylase, succinic dehydrogenase, ß-hydroxybutyrate dehydrogenase and ATPases. No activity of these enzymes was found in the scar, whereas a marked increase of alkaline phosphatase and dipeptidyl peptidase IV activities was found in the foci of fibrotization. Histochemical changes correlated with subcellular changes, which were characterized by 1) apparent fibroblast activation associated with interstitial/perivascular fibrosis, 2) heterogeneous population of the normal, hypertrophic and injured cardiomyocytes, 3) enhancement of the atrial granules and their translocation into the sarcolemma, and 4) impairment of capillaries as well as by induction of angiogenesis. Similar alterations were also found in the heart of captopril co-treated rats, despite of the significant suppression of blood pressure. The results indicate that NO-deficient hypertension is accompanied by metabolic disturbances and ultrastructural alterations of the heart and these changes are probably not induced by the renin-angiotensin system only., N. Tribulová, Ľ. Okruhlicová, I. Bernátová, O. Pecháňová., and Obsahuje bibliografii
Young castrated male goats (n = 8) were used to investigate the effect of long-term treatment with recombinant methionyl bovine somatotropin in a sustained release vehicle (bST; 100 mg at seven-day intervals in a 147-day experiment) and chronic culture (24 h) of omental adipose tissue in the presence of various hormones on lipogenic responses to catecholamines during acute incubation (2 h) in a sodium acetate supplemented glucose-free buffer. The rate of fatty acid synthesis in freshly-prepared adipose explants was low and did not differ from those cultured in the absence of hormones for 24 h. Hormonal combination of insulin (17 nmol.l-1) plus cortisol (138 nmol.l-1) or insulin plus recombinant enterokinase linker bST (4.5 nmol.l-1) increased lipogenesis (P<0.05). Further addition of bST or cortisol decreased lipogenesis significantly (P<0.05) in the controls but not significantly in bST-treated animals. Cultured explants from either control or bST-treated animals showed significant inhibition of lipogenesis by both norepinephrine (10 m mol.l-1) and isoprenaline (10 m mol.l-1). BST treatment in vivo did not increase the responsiveness of cultured explants to norepinephrine in vitro, however, the responsiveness to isoprenaline(inhibition of lipogenesis) was greater in bST-treated animals than in the controls., J. Škarda., and Obsahuje bibliografii