The aim of this in vitro study was to examine the secretion activity (progesterone, 17β-estradiol and insulin-like growth factor-I) of rat ovarian fragments after molybdenum (Mo) addition. Rat ovarian fragments were incubated with ammonium molybdate (NH4)6Mo7O24.4H2O at the doses 90, 170, 330 and 500 μg.ml-1 for 24 h and compared with control group without Mo addition. Release of progesterone (P4), estradiol (17β-estradiol) and insulin-like growth factor I (IGF-I) by ovarian fragments was assessed by radioimmunoassay (RIA). Data show that P4 release by ovarian fragments was not affected by (NH4)6.Mo7O24.4H2O addition at all the doses used (90-500 μg.ml-1). However, addition of ammonium molybdate was found to cause a significant (P<0.05) dose-dependent decrease (at the doses 90, 170 and 500 μg.ml-1) in release of 17β-estradiol by ovarian fragments in comparison to control. Also, addition of ammonium molybdate significantly (P<0.05) inhibited IGF-I release at all the doses (90-500 μg.ml-1) used in the study. Results suggest ammonium molybdate induced inhibition in the release of growth factor IGF-I and its dosedependent effect on secretion of steroid hormone 17β-estradiol but not progesterone. These data contribute to new insights regarding the mechanism of action of Mo on rat ovarian functions., S. Roychoudhury, L. Detvanova, A. V. Sirotkin, R. Toman, A. Kolesarova., and Obsahuje bibliografii
Skin healing process is postnatally always associated with scarring of various extent. Based on the clinical experience of plastic surgeons, the healing after lip cleft reconstruction is surprisingly almost scar-less when it is carried out within a few first days after birth. This phenomenon is not seen in delayed cases. In order to decipher causative mechanism, we have isolated and studied principal cell populations, keratinocytes and fibroblast, from residual tissue samples after reconstructive operation (N=39) performed at various age (0-9 years). These cells play the pivotal role in the healing and that is why we focused on description of their phenotype and also functionality with respect to age. We have identified a population of remarkably small cells in explants from newborns (day 0-10). These small cells were strongly positive for markers of low differentiated keratinocytes, keratin-8 and -19, and moreover also for vimentin. In the explants cultures from older babies this population was missing. Fibroblasts from newborns and older patients differed namely in terms of nestin expression and also in the production of extracellular matrix components. We conclude that in vitro described properties of keratinocytes and fibroblasts in newborns could participate on the almost scar-less wound healing in earliest neonatal period., E. Krejčí, O. Kodet, P. Szabo, J. Borský, K. Smetana Jr., M. Grim, B. Dvořánková., and Obsahuje bibliografii
Interspecies differences in glycosidation potential in mammalian tissues represent a factor contributing to ambiguity when endobiotic and/or xenobiotic metabolic pathways are extrapolated from animals to man. Using the TLC/autoradiographic technique, we conducted an in vitro investigation involving mouse, rat, monkey, as well as human liver and kidney microsomes to evaluate their glycoconjugation potential towards 3H-labeled, purine-derived selective inhibitors of cyclin-dependent kinases such as olomoucine, bohemine, roscovitine, 6-(2-hydroxybenzyl)amino-2-(1-hydroxymethyl-2-methylpropyl)amino-9-isopropylpurine (compound A-4), and 6-(3-hydroxybenzyl)amino-2-[(1(R/S)-hydroxymethyl)propyl]amino-9-isopropylpurine (compound A-5) as aglycones. Principally, this study confirmed the aliphatic hydroxyl group of olomoucine-type inhibitors as a relatively suitable target for glucuronide, glucoside, xyloside, galactoside, and/or N-acetylaminoglucoside conjugation. Of the tissues examined, only the mouse microsomes were able to perform glucosidation and galactosidation reactions with the aglycones. On the other hand, monkey microsomes were superior to the mouse microsomes in a variety of glucuronide conjugates produced with compounds A-4 and A-5., K. Červenková, M. Belejová, Z. Chmela, M. Rypka, D. Riegrová, K. Michnová, K. Michalíková, I. Šúrová, A. Brejcha, J. Hanuš, B. Černý, K. Fuksová, L. Havlíček, J. Veselý., and Obsahuje bibliografii
Several recent studies bring evidence of cell death enhancement in photodynamic compound loaded cells by ultrasonic treatment. There are a number of hypotheses suggesting the mechanism of the harmful ultrasonic effect. One of them considers a process in the activation of photosensitizers by ultrasonic energy. Because the basis of the photodynamic damaging effect on cells consists in the production of reactive oxygen species (ROS), we focused our study on whether the ultrasound can increase ROS production within cancer cells. Particularly, we studied ROS formation in ultrasound pretreated breast adenocarcinoma cells during photodynamic therapy in the presence of chloroaluminum phthalocyanine disulfonate (ClAlPcS2). Production of ROS was investigated by the molecular probe CM-H2DCFDA. Our results show that ClAlPcS2 induces higher ROS production in the ultrasound pretreated cell lines at a concentration of 100 μM and light intensity of 2 mW/cm2. We also observed a dependence of ROS production on photosensitizer concentration and light dose. These results demonstrate that the photodynamic effect on breast cancer cells can be enhanced by ultrasound pretreatment., H. Kolářová, R. Bajgar, K. Tománková, E. Krestýn, L. Doležal, J. Hálek., and Obsahuje bibliografii
Treatment with pertussis toxin (PTX) which eliminates the activity of Gi proteins effectively reduces blood pressure (BP) and vascular resistance in spontaneously hypertensive rats (SHR). In this study we have compared the functional characteristics of isolated arteries from SHR with and without PTX-treatment (10 μg/kg i.v., 48 h before the experiment). Rings of thoracic aorta, superior mesenteric artery and main pulmonary artery were studied under isometric conditions to measure the reactivity of these vessels to receptor agonists and to transmural electrical stimuli. We have found that the treatment of SHR with PTX had no effect on endothelium-dependent relaxation of thoracic aorta induced by acetylcholine. In PTX-treated SHR, the maximum contraction of mesenteric artery to exogenous noradrenaline was reduced and the dose-response curve to cumulative concentration of noradrenaline was shifted to the right. Similarly, a reduction in the magnitude of neurogenic contractions elicited by electrical stimulation of perivascular nerves was observed in the mesenteric artery from PTX-treated SHR. PTX treatment of SHR also abolished the potentiating effect of angiotensin II on neurogenic contractions of the main pulmonary artery. These results indicate that PTX treatment markedly diminishes the effectiveness of adrenergic stimuli in vasculature of SHR. This could importantly affect BP regulation in genetic hypertension., A. Zemančíková, J. Török, J. Zicha, J. Kuneš., and Obsahuje bibliografii a bibliografické odkazy
In hemodialyzed patients hormonal disturbances are known to occur. However, melatonin levels have not been completely studied. The aim of the study was to find whether changes in calcaemia affect melatonin secretion. For this reason we followed the nocturnal serum concentrations of melatonin and parathyroid hormone (PTH) in 9 hemodialyzed patients (6 women and 3 men, aged 37-65 years) both before and 1-3 months after parathyroidectomy at 6 p.m., 9 p.m., 11 p.m., 2 a.m., 5 a.m. and 7 a.m. At 6 p.m. blood samples to evaluate the levels of calcium and phosphate were also collected. Parathyroidectomy resulted in an increase in nocturnal melatonin levels. As expected, the parathyroidectomy was followed by considerable PTH decrease. PTH showed no nocturnal variation before or after parathyroidectomy. Calcium levels significantly decreased after the operation while phosphate levels increased. In summary, in hemodialyzed patients with hyperparathyroidism, parathyroidectomy significantly increases the nocturnal secretion of melatonin. Relationships between the pineal gland and parathyroid glands have yet to be elucidated., R. Kancheva, S. Sulková, F. Švára, M. Hill, L. Kanchev, I. Žofková., and Obsahuje bibliografii a bibliografické odkazy
Critical illness induces among other events production of proinflammatory cytokines that in turn interfere with insulin signaling cascade and induce insulin resistance on a postreceptor level. Recently, local renin-angiotensin system of adipose tissue has been suggested as a possible contributor to the development of insulin resistance in patients with obesity. The aim of our study was to determine local changes of the renin-angiotensin system of subcutaneous and epicardial adipose tissue during a major cardiac surgery, which may serve as a model of an acute stress potentially affecting endocrine function of adipose tissue. Ten patients undergoing elective cardiac surgery were included into the study. Blood samples and samples of subcutaneous and epicardial adipose tissue were collected at the beginning and at the end of the surgery. Blood glucose, serum insulin and adiponectin levels were measured and mRNA for angiotensinogen, angiotensin-converting enzyme and angiotensin II type 1 receptor were determined in adipose tissue samples using RT PCR. Cardiac surgery significantly increased both insulin and blood glucose levels suggesting the development of insulin resistance, while serum adiponectin levels did not change. Expression of angiotensinogen mRNA significantly increased in epicardial adipose tissue at the end of surgery relative to baseline but remained unchanged in subcutaneous adipose tissue. Fat expression of angiotensin-converting enzyme and type 1 receptor for angiotensin II were not affected by surgery. Our study suggests that increased angiotensinogen production in epicardial adipose tissue may contribute to the development of postoperative insulin resistance., T. Roubíček, M. Dolinková, J. Bláha, D. Haluzíková, L. Bošanská, M. Mráz, J. Křemen, M. Haluzík., and Obsahuje bibliografii a bibliografické odkazy
Previously, increased diameter and enhanced myogenic tone were seen after 2-week 45º head-up (HUT2) in the rat. We studied the reversibility and the effect of extended tilt on this phenomenon using two experimental groups: HUT2 plus 2-week horizontal (HUT2HOR2), and 4-week tilting (HUT4). 4-weeks in normal cages (NC4) served as control. Diameter of saphenous vein (SV) in 2-20 mm Hg pressure range, wall and media thickness, endothelial and smooth muscle cell densities, and cell proliferation were measured. The diameter of SV from HUT4 was significantly larger compared with HUT2HOR2 or NC4 within the whole pressure range both in Krebs-Ringer (870.4±21.3 vs. 778.2±24.9 and 771.6±28.1 μm at 10 mm Hg, respectively) and in Ca2+-free solution. Myogenic and norepinephrine-induced vascular tone, wall and media thickness did not differ among the three groups. Endothelial cell density decreased in HUT4 (10.7±1.2) vs. HUT2HOR2 (15.1±1.0) and NC4 (15.3±0.6), while that of smooth muscle was unchanged. No cell proliferation marker was seen. In conclusion, both increased diameter and enhanced myogenic tone of SV seen in HUT2 proved to be reversible. HUT4 resulted in increased SV diameter, similarly to HUT2, however, vascular tone was not amplified. This suggests that a prolonged orthostatic load may readjust the function of smooth muscle., G. Raffai, C. Lódi, G. Illyés, G. Nádasy, E. Monos., and Obsahuje bibliografii a bibliografické odkazy
Knowledge on the involvement of spinal COX-1 and COX-2 in pain due to osteoarthritis could be useful for better understanding of its pa thogenesis and therapy. In this study we have investigated a long-term pattern of expression and production of spinal COX-1 and COX-2 in the model of osteoarthritis induced in rats by injection of monoiodoacetate (MIA) into the knee joint. MIA injection produced thermal hyperalgesia (assessed by the plantar test) and tactile allodynia (measured with von Frey hairs). The pain measures reached maximum on the 5th day, then re mained relatively stable. The expression of spinal COX-2 mR NA reached maximum on day 5 (5.2 times; P<0.001) and remain ed increased until day 31 (4.9 times; P<0.001). Expression of spinal COX-1 mRNA increased gradually reaching maximum on the day 31 (4.5 times; P<0.001) when the relative expression of both genes was almost equal. The production of both proteins was almost similar at the beginning of the experiment. The highest production of COX-2 protein was observed on day 5 after the induction of osteoarthritis (increased 3.9 times). The levels of COX-1 protein increased gradually with maximum on day 31 (3.4 times). The present findings indicate that not only expression of COX-2 mRNA but also that of COX-1 mRNA is significantly increased in the spine during osteoarthritis pain. Thus, in contrast to inflammatory pain, the upregulation of spinal COX-1 may be important in osteoarthritis pain., M. Procházková, P. Zanvit, T. Doležal, L. Prokešová, M. Kršiak., and Obsahuje bibliografii
Anorexia nervosa (AN) is characterized by self-induced starvation leading to severe weight and fat loss. In the present study, we measured fasting plasma levels of adiponectin, leptin, resistin, insulin and glucose in 10 women with a restrictive type of AN and in 12 healthy women (C). Insulin sensitivity was determined according to homeostasis model assessment of insulin resistance (HOMA-R). Plasma resistin, leptin and insulin levels were significantly decreased, whereas plasma adiponectin levels were significantly increased in patients with AN compared to the C. HOMA-R was significantly decreased in patients with AN compared to the C group. Plasma adiponectin and leptin concentrations negatively and positively correlated with the body mass index and percentage body fat in both groups. Plasma adiponectin levels were negatively related to plasma insulin levels in the AN group only. In conclusion, we demonstrated that AN is associated with significantly decreased plasma leptin and resistin levels, markedly increased plasma adiponectin levels and increased insulin sensitivity. Plasma leptin and adiponectin levels were related to the body size and adiposity. Hyperadiponectinemia could play a role in increased insulin sensitivity of patients with AN. Neither body size and adiposity nor insulin sensitivity are the major determinants of plasma resistin levels in AN. and Obsahuje bibliografii a bibliografické odkazy