Earlier this month, the Czech media reported that a highly efficient antiviral drug developed by Czech scientists has been shelved, reportedly for fear it would compete with existing medicines manufactured by pharmaceutical giants. The substance, known as MK-612, was designed at the Academy´s Institute of Organic Chemistry and Biochemistry. Academic Bulletin interviewed Zdeněk Havlas, headmaster of the Institute, about next stage in the future of this efficient substance MK-612. and Marina Hužvárová.
Depression is a complex disorder related to chronic inflammatory processes, chronic stress changes and a hippocampal response. There is a increasing knowledge about the role of glial cells in nutrient supply to neurons, maintenance of synaptic contacts and tissue homeostasis within the CNS. Glial cells, viewed in the past as passive elements with a limited influence on neuronal function, are becoming recognized as active partners of neurons and are starting to be discussed as a possible therapeutic target. Their role in the pathogenesis of depressive disorders is also being reconsidered. Attention is devoted to studies of the different types of antidepressants and their effects on transmembrane signaling, including levels of α subunits of G proteins in C6 glioma cells in vitro as a model of postsynaptic changes in vivo. These models indicate similarities in antidepressant effects on G proteins of brain cells and effector cells of natural immunity, natural killers and granulocytes. Thus, an antidepressant response can exhibit certain common characteristics in functionally different systems which also participate in disease pathogenesis. There are, however, differences in the astrocyte G-protein responses to antidepressant treatment, indicating that antidepressants differ in their effect on glial signalization. Today mainstream approach to neurobiological basis of depressive disorders and other mood illnesses is linked to abnormalities in transmembrane signal transduction via G-protein coupled receptors. Intracellular signalization cascade modulation results in the activation of transcription factors with subsequent increased production of a wide array of products including growth factors and to changes in cellular activity and reactivity., M. Páv, H. Kovářů, A. Fišerová, E. Havrdová, V. Lisá., and Obsahuje bibliografii a bibliografické odkazy
Rhythmic daily changes in the Na,K-ATPase activity have been previously described for rat kidney cortex, showing two peaks: at 0900 h and 2100 h, and two valleys: at 1500 h and 0100 h - 0300 h. The oscillations in Na,K-ATPase activity are produced by an inhibitor, which binds the enzyme and is present in the rat blood plasma at valley times and absent or at very low concentrations at peak times. Since it has been demonstrated that active Na+ extrusion from the cells of several tissues depends not only on the Na,K-ATPase but also on the ouabain-insensitive Na-ATPase, we studied the activity of this latter enzyme of several rat tissues, i.e., kidney cortex, small intestine, liver, heart and red blood cells along the day. None of these tissues showed any variation of their Na-ATPase activity along the day. Preincubation of kidney cortex homogenates obtained at 0900 h, with blood plasma drawn at 0900 h and 1500 h, did not modify the Na-ATPase activity. Our results indicate that the Na-ATPase activity does not oscillate along the day. These results are in agreement with the idea that the Na-ATPase could partially compensate the Na+ transport affected by oscillations of the Na,K-ATPase activity., A. Reyes ... [et al.]., and Obsahuje seznam literatury
The review is done to summarise the history of the discoveries of the many anatomical, agronomical, and physiological aspects of C4 photosynthesis (where the first chemical products of CO2 fixation in illuminated leaves are four-carbon dicarboxylic acids) and to document correctly the scientists at the University of Arizona and the University of California, Davis, who made these early discoveries. The findings were milestones in plant science that occurred shortly after the biochemical pathway of C3 photosynthesis in green algae (where the first chemical product is a three-carbon compound) was elucidated at the University of California, Berkeley, and earned a Nobel Prize in chemistry. These remarkable achievements were the result of ground-breaking pioneering research efforts carried out by many agronomists, plant physiologists and biochemists in several laboratories, particularly in the USA. Numerous reviews and books written in the past four decades on the history of C4 photosynthesis have focused on the biochemical aspects and give an unbalanced history of the multidisciplinary/multinstitutional nature of the achievements made by agronomists, who published much of their work in Crop Science. Most notable among the characteristics of the C4 species that differentiated them from the C3 ones are: (I) high optimum temperature and high irradiance saturation for maximum leaf photosynthetic rates; (II) apparent lack of CO2 release in a rapid stream of CO2-free air in illuminated leaves in varying temperatures and high irradiances; (III) a very low CO2 compensation point; (IV) lower mesophyll resistances to CO2 diffusion coupled with higher stomatal resistances, and, hence, higher instantaneous leaf water use efficiency; (V) the existence of the so-called "Kranz leaf anatomy" and the higher internal exposed mesophyll surface area per cell volume; and (VI) the ability to recycle respiratory CO2 by illuminated leaves.
Functional C(-260)→T polymorphism in the promoter of the CD14 gene has been reported to be associated with coronary heart disease (CHD). The functional role of the polymorphism, however, is still a matter of debate, since several studies have not proved its effect on clinical outcomes associated with atherosclerosis. Cardiovascular-related morbidity and mortality was assessed in a post-hoc approach four years after baseline characterization of patients (male/female n = 36/32) with angiographically proven coronary heart disease. CD14 C(-260)→T promoter genotype was determined at baseline. Seventeen out of 20 CHD patients with non-lethal cardiovascular events carried at least one T-allele. CD14 T-260 allele carriers have a 3.59-fold (95 % confidence interval: 1.11-6.75) increased risk for non-lethal cardiovascular events (Kaplan-Meier plot: log rank test p = 0. 029). All patients with lethal outcomes (n = 6) were also T-allele carriers. Multivariate logistic regression analysis among CHD patients including age, established risk factors and the C(-260)→T polymorphism as covariates and non-lethal events as a dependent variable confirmed the independent prospective effect of the T-allele on cardiovascular outcomes in this subset. Further evidence is provided for the role of CD14 C(-260)→T promoter polymorphism as a genetic susceptibility marker of atherosclerosis in patients with an advanced clinical course of the disease. Due to the small sample size and post-hoc character of the study large-scale prospective studies that monitor patients with proven CHD are needed to confirm these findings., M. Porsch-Öucürümez, J.Hucke, S. Westphal, J. A. Hubáček, G. Schmitz, C. Luley., and Obsahuje bibliografii a bibliografické odkazy
Metabolic consequences of direct muscle trauma are insufficiently defined. Their effects on the ubiquitin-proteasome pathway (UPP) of protein degradation in human skeletal muscles are as yet unknown. Thus, we investigated whether the UPP is involved in the metabolic response evoked in directly traumatized human skeletal muscles. Biopsies were obtained from contused muscles after fractures and from normal muscles during elective implant removal (control). As estimated by western blot analyses, concentrations of free ubiquitin and ubiquitin protein conjugates were similar in extracts from injured and uninjured muscles. Ubiquitin protein ligation rates were reduced after injury (1.5±0.2 vs. 1.0±0.15 fkat/μg; p=0.04). Chymotryptic-, tryptic- and caspase-like proteasome peptidase activities (total activity minus activity in the presence of proteasome inhibitors) increased significantly after trauma (p=0.04 - 0.001). Significant increases in total chymotryptic- and caspase-like activities were attributable to proteasome activation. Our results extend the possible role of the UPP in muscle wasting to direct muscle trauma. They further suggest that the effects of direct mechanical trauma are not limited to the proteasome and imply that ubiquitin protein ligase systems are also involved. Based on the potential role of the UPP in systemic diseases, it might also be a therapeutic target to influence muscle loss in critically ill blunt trauma patients, in which large proportions of muscle are exposed to direct trauma. and Obsahuje bibliografii a bibliografické odkazy
Central administration of losartan effectively blocked the increase of blood pressure and drinking response induced by angiotensin II (Ang II) or carbachol. However, the relationship between angiotensin AT1 receptors and the natriuresis induced by brain cholinergic stimuli is still not clear. The purpose of the study is to reveal the role of brain angiotensin AT1 receptor in the carbachol-induced natriuresis and expression of neuronal nitric oxide synthase (nNOS) in the locus coeruleus (LC) and proximal co nvoluted tubule (PCT). Our results indicated that 40 min after in tracerebroventricular (ICV) injection of carbachol (0.5 μg), urinary sodium excretion was significantly increased to 0.548±0.049 μmol·min-1·100 g-1. Immunohistochemistry showed that carbachol induced an increase of neuronal nitric oxide synthase immunoreactivity (nNOS-IR) in the LC and renal proximal tubular cells. After pretreatment with losartan (20 μg), carbachol-induced urinary sodium excretion was reduced to 0.249±0.067 μmol·min-1·100 g-1. The same was true for carbachol-induced increase of nNOS-IR in the LC and PCT. The present data suggest that ICV cholinergic stimulation could induce a natriuresis and upregulate the activity of nNOS in the LC and PCT. The blockade of AT1 receptors might downregulate the effects induced by carbachol in the LC and PCT. Consequently, we provide a new evidence that brain angiotensinergic pathway and NO-dependent neural pathway contribute to the natriuresis following brain cholinergic stimulation and thus play an important role in the regulation of fluid homeostasis. Furthermore, the final effect of nitric oxide on proximal tubular sodium reabsorption participated in the natriuresis induced by brain cholinergic stimulation., M. Wang, C. L. Jiang, C. Y. Wang, Q. Y. Yao., and Obsahuje bibliografii a bibliografické odkazy
We present a review about the relationship between ryanodine receptors and voltage-gated calcium channels in myocardium, and also how both of them are related to protein kinase A. Ryanodine receptors, which have three subtypes (RyR1-3), are located on the membrane of sarcoplasmic reticulum. Different subtypes of voltage-gated calcium channels interact with ryanodine receptors in skeletal and cardiac muscle tissue. The mechanism of excitation-contraction coupling is therefore different in the skeletal and cardiac muscle. However, in both tissues ryanodine receptors and voltage-gated calcium channels seem to be physically connected. FK-506 binding proteins (FKBPs) are bound to ryanodine receptors, thus allowing their concerted activity, called coupled gating. The activity of both ryanodine receptors and voltage-gated calcium channels is positively regulated by protein kinase A. These effects are, therefore, components of the mechanism of sympathetic stimulation of myocytes. The specificity of this enzyme’s targeting is achieved by using different A kinase adapting proteins. Different diseases are related to inborn or acquired changes in ryanodine receptor activity in cardiac myocytes. Mutations in the cardiac ryanodine receptor gene can cause catecholamine-provoked ventricular tachycardia. Changes in phosphorylation state of ryanodine receptors can provide a credible explanation for the development of heart failure. The restoration of their normal level of phosphorylation could explain the positive effect of beta-blockers in the treatment of this disease. In conclusion, molecular interactions of ryanodine receptors and voltage-gated calcium channels with PKA have a significant physiological role. However, their defects and alterations can result in serious disturbances., M. M. Petrovič, K. Valeš, B. Putnikovič, V. Djulejič, D. M. Mitrovič., and Obsahuje bibliografii a bibliografické odkazy
Serum adipocyte fatty acid-binding protein (FABP) concentrations are linked to human obesity and other features of metabolic syndrome. Whether FABP associates with metabolic alterations in chronic malnutrition is unknown. In the present study, we measured fasting serum levels of FABP, leptin, soluble leptin receptor, adiponectin, resistin, C-reactive protein (CRP), insulin, glucose, cholesterol and triglycerides in 19 patients with a restrictive type of anorexia nervosa (AN) and in 16 healthy age-matched control women (C). Body mass index, serum leptin, and CRP concentrations were significantly lower, while serum adiponectin and soluble leptin receptor levels were significantly higher in AN relative to C group. Serum insulin, glucose, cholesterol and triglyceride levels did not differ between the groups studied. Serum FABP leve ls were unchanged in patients with AN and were not related to any of parameters studied. We conclude that, in contrast to patients with obesity where FAPB is a prominent marker of metabolic alterations, chronic malnutrition in AN does not significantly affect its serum levels., D. Haluzíková ... [et al.]., and Obsahuje seznam literatury