Maternal hyperandrogenism during pregnancy might have metabolic and endocrine consequences on the offspring as shown for the polycystic ovary syndrome. Despite numerous experiments, the impact of prenatal hyperandrogenic environment on postnatal sex steroid milieu is not yet clear. In this study, we investigated the effect of prenatal testosterone excess on postnatal concentrations of luteinizing hormone, corticosterone and steroid hormones including testosterone, pregnenolone, progesterone, estradiol and 7β-hydroxyepiandrosterone in the offspring of both sexes. Pregnant rats were injected daily with either testosterone propionate or vehicle from gestational day 14 until parturition. The hormones were evaluated in plasma of the adult offspring. As expected, females had lower testosterone and higher pregnenolone, progesterone and estradiol in comparison to males. In addition, corticosterone was higher in females than in males, and it was further elevated by prenatal testosterone treatment. In males, prenatal testosterone exposure resulted in higher 7β-hydroxyepiandrosterone in comparison to control group. None of the other analyzed hormones were affected by prenatal testosterone. In conclusion, our results did not show major effects on sex hormone production or luteinizing hormone release in adult rats resulting from testosterone excess during their fetal development. However, maternal hyperandrogenism seems to partially affect steroid biosynthesis in sex-specific manner., E. Domonkos, V. Borbélyová, L. Kolátorová, T. Chlupáčová, D. Ostatníková, J. Hodosy, L. Stárka, P. Celec., and Obsahuje bibliografii
To determine whether a short-term change in dietary habits affects postprandial lipemia in men and women in the same way, postprandial triglyceridemia was measured in age- and BMI-matched young healthy men and women after two weeks on the self-selected low-fat low-cholesterol (LF) diet and after another two weeks on the self-selected high-fat high-cholesterol (HF) diet. After a standardized challenge meal (1.4 g fat/kg of body weight), men had higher postprandial triglyceridemia than women on the HF diet but no such difference was observed on the LF diet. The results of this preliminary study suggest that there may be important sex differences in the mechanisms regulating the postprandial lipemia response to different diets, women being able to adapt better to the HF diet with respect to postprandial lipemia., J. Kovář, R. Poledne., and Obsahuje bibliografii
Acute liver failure (ALF) is a clinical syndrome with high mortality rate, resulting from widespread hepatocyte damage. Its pathophysiological background is still poorly understood and preclinical studies evaluating pathophysiology and new potential therapeutic measures are needed. The model of ALF induced by administration of thioacetamide (TAA) in Lewis rats is recommended as optimal; however, the limitation of previous studies was that they were performed predominantly in male rats. In view of the growing recognition that sex as a biological variable should be taken into consideration in preclinical research, we examined its role in the development of TAA-induced ALF in Lewis rats. We found that, first, intact male Lewis rats showed lower survival rate than their female counterparts, due to augmented liver injury documented by higher plasma ammonia, and bilirubin levels and alanine aminotransferase activity. Second, in female rats castration did not alter the course of TAA-induced ALF whereas in the male gonadectomy improved the survival rate and attenuated liver injury, reducing it to levels observed in their female counterparts. In conclusion, we found that Lewis rats show a remarkable sexual dimorphism with respect to TAA-induced ALF, and male rats display dramatically poorer prognosis as compared with the females. We showed that testosterone is responsible for the deterioration of the course of TAA-induced ALF in male rats. In most general terms, our findings indicate that in the preclinical studies of the pathophysiology and treatment of ALF (at least of the TAA-induced form) the sex-linked differences should be seriously considered., Eva Koblihová, Iveta Mrázová, Zdenka Vaňourková, Hana Maxová, Miroslav Ryska, Jiří Froněk., and Obsahuje bibliografii
Methylphenidate is commonly used for the treatment of attention deficit hyperactivity disorder. The cardiovascular safety of methylphenidate has been a subject of debate with some studies indicating that methylphenidate increases the likelihood of experiencing a myocardial infarction. However, it is unknown whether methylphenidate worsens the extent of injury during an ischemic insult. The purpose of this study was to determine whether short term exposure to methylphenidate increases the extent of myocardial injury during an ischemic insult. Male and female rats received methylphenidate (5 mg/kg/day) or saline for 10 days by oral gavage. Hearts were subjected to 20 min of ischemia and 2 h of reperfusion on a Langendorff isolated heart apparatus on day 11. Cardiac contractile function was monitored via an intraventricular balloon and myocardial injury was assessed by triphenyltetrazolium chloride staining. Methylphenidate significantly increased locomotor activity in male and female rats, confirming absorption of this psychostimulant into the central nervous system. Male hearts had significantly larger infarcts than female hearts, but methylphenidate had no impact on infarct size or postischemic recovery of contractile function in hearts of either sex. These data indicate that methylphenidate does not increase the extent of injury induced by an ischemic insult., Sarah L. Seeley, Manoranjan S. D’Souza, Thorne S. Stoops, Boyd R. Rorabaugh., and Obsahuje bibliografii
As wine polyphenols were show n to possess many positive effects in mammals, including improvement of vascular function, this study investigated the effect of the Slovak Alibernet red wine extract (AWE) on blood pressure and vascular function in young normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. Six weeks old, male, WKY and SHR were treated with AWE for three weeks at the dose of 24.2 mg/kg/day. Blood pressure (BP), determined by tail-cuff plethysmography, was significantly elevated in SHR vs. WKY and AWE failed to affect it. Lipid peroxidation was evaluated by determination of thiobarbituric acid-reactive substances. Vascular function was assessed in rings of the femoral artery using Mulvany-Halpern’s myograph. Maximal endothelium-dependent acetylcholine (ACh)-induced rela xation was reduced in control SHR vs. WKY rats by approximatel y 9.3 %, which was associated with a significant decrease of its NO-independent component. AWE failed to affect maximal AC h-induced relaxation, both its NO-dependent and independen t components, compared to controls of the same genotype. AWE however reduced lipid peroxidation in the left ventricle of both WKY and SHR and in the liver of SHR. In conclusion, three-week administration of AWE failed to reduce BP and to improve endothelial function in the femoral arteries of both genotypes investigated., P. Bališ ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
The aim of the present study was to investigate the effects of Angiotensin II (Ang II) and Arginin-Vasopressin (AVP) on contractility of non-pregnant uterus in diabetic Wistar rats and to explore whether one-week administration of Melatonin (MLT) or Ghrelin (GHR) will change the response of diabetic uterine muscle to AngII and AVP. Uterine horns, prepared by the method of isolated tissues were investigated as w ell as glycemic profile, blood pressure and body weight. The research of smooth muscle contractions was made by a new method of analysis, characterizing in detail the various phases of the myometrial activity. Differences in the development of the peptide-mediated smooth muscle contractions depending on the phase of the estrous cycle were observed. Experimental diabetes had a pronounced negative effect on force and time-parameters of AngII and AVP-stimulated uterine contractions. Administration of GHR or MLT had a beneficial effect on the glycemic status of diabetic rats and partially improved the response of uterine preparations to the peptides. The application of MLT increased both force and time-parameters of Ang II- and AVP-stimulated uterine contractions while treatment with GHR increased power characteristics and shortened contraction and relaxation of the smooth muscle process., T. Georgiev, A. Tolekova, R. Kalfin, P. Hadzhibozheva., and Obsahuje bibliografii
The aim of this study was the histochemical characterization of NADPH diaphorase-positive neuronal pools in the rabbit lumbosacral segments using a model of single, repeated and multiple sublethal spinal cord ischemia. Following a single 8-min sublethal spinal cord ischemia and 1-hour reperfusion, the staining of NADPH diaphorase-exhibiting neurons in the dorsal horn, pericentral region, dorsal gray commissure and sacral parasympathetic nucleus was comparable with the control sections. In contrast to the foregoing sublethal ischemia, a regionally different somatic NADPH diaphorase (NADPHd) staining was found after multiple sublethal spinal cord ischemia. Whereas an almost complete loss of the staining of large NADPHd-exhibiting somata in the pericentral region was detected, the staining of the NADPHd-exhibiting neuronal pools in the deep dorsal horn and sacral parasympathetic nucleus was fully preserved. Concomitantly, a prominent reduction of small NADPH diaphorase -positive neurons was noted in the superficial dorsal horn layers of lower lumbar and sacral segments., J. Maršala, P. Jalč., and Obsahuje bibliografii
In our previous study, healthy volunteers showed considerable short-term dynamics and patterns of the coherence of high time resolution between respiratory movements (RESP), heart rate fluctuations (HRF), and arterial blood pressure fluctuations (BPF). These are physiological indicators of autonomic short-term coordination mediated mainly by the brainstem which could be impaired in severe brain disorders. We hypothesized a direct or indirect impairment of these functions by these disorders and examined these patterns in 16 patients suffering from severe brain disorders. We calculated partial and ordinary coherence sequences and found almost the same patterns of coherence sequences as in healthy volunteers, but a distinctly reduced frequency of pattern incidence in patients (2.8*1.5/10 min/patient and 9.5*2.8/10 min/subject, P<0.05). Furthermore, there is a significantly smaller frequency of HRF-related patterns in patients with poor outcome, compared with those in patients with good outcome (1.8*0.8/10 min/patient and 4.5*2.7/10 min/patient, P<0.05). We conclude that severe brain disorders reduce physiological short-term dynamics of autonomic coordination patterns in the mean values of patients, but not in every patient., U. Zwiener, Ch. Schelenz, S. Bramer, D. Hoyer., and Obsahuje bibliografii
The possible linear short-term coordination between respiratory movements (RESP), heart rate fluctuations (HRF), and arterial blood pressure fluctuations (BPF) in conscious human beings has not yet been investigated because of the restricted time resolution of conventional time series analysis. At present, this short-term dynamics as an expression of relative coordination can be quantified by newly developed adaptive autoregressive modeling of time series using Kalman filtering. Thus, in 6 conscious healthy volunteers, RESP, HRF, and BPF were recorded during 10 min in the supine position, at rest and during paced breathing. A considerable part of calculated ordinary and partial coherence sequences of short-term resolution between RESP and HRF, RESP and BPF, and partially between HRF and BPF showed patterns varying in time that could be correlated to changes between gradual coordinations (coherence changing between 0.40 and 0.95). They were more seldom complete or absent. There were mostly opposite changes between partial coherence sequences RESP-HRF/BPF and RESP-BPF/HRF demonstrating competitive behavior between these coordinations. Paced breathing did not essentially affect any observed characteristics. Therefore, these coherence dynamics are not essentially dependent on voluntary breathing movements. We conclude that to a different extent these linear and changing couplings between RESP, HRF, and BPF in conscious human beings exhibit properties of short-term complete and more frequently gradual coordinations showing dynamics that can not be determined by conventional methods., U. Zwiener, C. Schelenz, S. Bramer, D. Hoyer., and Obsahuje bibliografii
The effect of three-day fasting on cardiac ischemic tolerance was investigated in adult male Wistar rats. Anesthetized open-chest animals (pentobarbitone 60 mg/kg, i.p.) were subjected to 20-min left anterior descending coronary artery occlusion and 3-h reperfusion for infarct size determination. Ventricular arrhythmias were monitored during ischemia and at the beginning (3 min) of reperfusion. Myocardial concentrations of beta-hydroxybutyrate and acetoacetate were measured to assess mitochondrial redox state. Short-term fasting limited the infarct size (48.5±3.3 % of the area at risk) compared to controls (74.3±2.2 %) and reduced the total number of premature ventricular complexes (12.5±5.8) compared to controls (194.9±21.9) as well as the duration of ventricular tachycardia (0.6±0.4 s vs. 18.8±2.5 s) occurring at early reperfusion. Additionally, fasting increased the concentration of beta-hydroxybutyrate and betahydroxybutyrate/acetoacetate ratio (87.8±27.0) compared to controls (7.9±1.7), reflecting altered mitochondrial redox state. It is concluded that three-day fasting effectively protected rat hearts against major endpoints of acute I/R injury. Further studies are needed to find out whether these beneficial effects can be linked to altered mitochondrial redox state resulting from increased ketogenesis., M. Šnorek ... [et al.]., and Obsahuje seznam literatury