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562. Allelic and Haplotype Frequencies of the p53 Polymorphisms in Brain Tumor Patients
- Creator:
- Erik Biroš, Ivan Kalina, Anton Kohút, Bogyiová, E., Šalagovič, J., and Igor Šulla
- Format:
- print, bez média, and svazek
- Type:
- article, studie, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Brain tumor, Susceptibility, p53, Polymorphism, 14, and 612
- Language:
- English
- Description:
- The polymorphisms of the tumor suppressor gene p53 in exon 4 (p53 BstUI) and in intron 6 (p53 MspI) have been suggested to be associated with the genetically determined susceptibility in diverse types of human cancer. In our hospital-based case-control study, we examined the allele and genotype incidence of these polymorphisms as well as their haplotype combinations in 60 brain tumor patients (27 males and 33 females) and 183 controls without malignancies. The genotype characteristics were determined by the PCR-based RFLP method using DNA extracted from peripheral blood. In this study we show that the p53 BstUI and the p53 MspI polymorphisms are not associated with increased risk of brain tumors. Thus, we conclude that the p53 BstUI and the p53 MspI polymorphic sites within the tumor suppressor gene p53 do not represent genetic determinants of susceptibility to brain tumors., E. Biroš, I. Kalina, A. Kohút, E. Bogyiová, J. Šalagovič, I. Šulla., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
563. Allelic variants of cytochrome P450 monooxygenases: Constitutive and insecticide-mediated expression in a Malaysian strain of the dengue vector, Aedes aegypti (Diptera: Culicidae)
- Creator:
- El-Garj, Fatma M. A, Wajidi, Mustafa F. F., and Avicor, Silas W.
- Format:
- print, počítač, and online zdroj
- Type:
- article, články, journal articles, model:article, and TEXT
- Subject:
- Zoologie, Diptera, Culicidae, Aedes aegypti, cytochrome P450s, structure prediction, mRNA expression, insecticide, 2, and 59
- Language:
- English
- Description:
- Cytochrome P450s (P450s) involved in insecticide resistance reduce the efficacy of insecticide-based vector control by rendering vector control ineffective. They are recorded in many species of vectors and have various constitutive and insecticide induction profiles. In this study, the isolation and prediction of the structure of a P450 from a strain of Aedes aegypti originating from Malaysia is reported. Quantitative mRNA expression of this gene and a previously reported P450, CYP4H28v2, in the developmental stages of the mosquito after exposure to sub-lethal concentrations of insecticides is also reported. The isolated P450, CYP4H31v2, is an allelic variant of CYP4H31 and contains several conserved motifs of P450s. The secondary structure of the protein is mostly made up of alpha helices and random coils. The tertiary structure was generated using homology modeling and was of good quality based on structure validation using protein structure assessment tools. CYP4H28v2 and CYP4H31v2 were differentially expressed in the developmental stages of the vector, with a significantly increased expression in adult males. The genes were significantly over-expressed in larvae exposed to deltamethrin and permethrin for 6 h. In the DDT-treated larvae, only CYP4H31v2 was significantly over-expressed after a 6 h exposure. Under-expression of the genes was predominant in larvae treated with the organophosphates malathion and temephos. Though the functions of these P450s are unknown, their response to induction by exposure to insecticides indicates the likely involvement of these genes in insecticide tolerance. and Fatma M. A. El-Garj, Mustafa F.F. Wajidi, Silas W. Avicor.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
564. Allopurinol intake does not modify the slow component of V O2 kinetics and oxidative stress induced by severe intensity exercise
- Creator:
- Olek, R. A., Safranow, K., Jakubowska, K., Olszewska, M., Chlubek, D., and Laskowski, R.
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, xanthine oxidase, total antioxidant status, reactive oxygen species, 14, and 612
- Language:
- English
- Description:
- The aim of this study was to test the hypothesis that allopurinol ingestion modifies the slow component of • VO2 kinetics and changes plasma oxidative stress markers during severe intensity exercise. Six recreationally active male subjects were randomly assigned to receive a single dose of allopurinol (300 mg) or a placebo in a double-blind, placebo-controlled crossover design, with at least 7 days washout period between the two conditions. Two hours following allopurinol or placebo intake, subjects completed a 6-min bout of cycle exercise with the power output corresponding to 75 % • VO2 max. Blood samples were taken prior to commencing the exercise and then 5 minutes upon completion. Allopurinol intake caused increase in resting xanthine and hypoxanthine plasma concentrations, however it did not affect the slow component of oxygen uptake during exercise. Exercise elevated plasma inosine, hypoxanthine, and xanthine. Moreover, exercise induced a decrease in total antioxidant status, and sulfhydryl groups. However, no interaction treatment x time has been observed. Short term severe intensity exercise induces oxidative stress, but xanthine oxidase inhibition does not modify either the kinetics of oxygen consumption or reactive oxygen species overproduction., R. A. Olek ... [et al.]., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
565. Allosteric modulation of ligand gated ion channels by ivermectin
- Creator:
- Hana Zemková, Tvrdonová, V., Anirban Bhattacharya, and Marie Jindřichová
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, iontové kanály, ion channels, cys-loop receptor family, purinergic P2X4 receptor, ivermectin, transmembrane domain, 14, and 612
- Language:
- English
- Description:
- Ivermectin acts as a positive allosteric regulator of several ligand gated channels including the glutamate-gated chloride channel (GluCl), γ-aminobutyric acid type-A receptor, glycine receptor, neuronal α 7-nicotinic receptor and purinergic P2X4 receptor. In most of the ivermect in-sensitive channe ls, the effects of ivermectin include the potentiation of agonist-induced currents at low concentrations and channel opening at higher concentrations. Based on mutagenesis, electrophysiological recordings and functional an alysis of chimeras between ivermectin-sensitive and ivermectin-insensitive receptors, it has been concluded that ivermectin acts by insertion between transmembrane helices. The three-dimensional structure of C. elegans GluCl complexed with ivermectin has revealed the details of the ivermectin-binding site, however, no generic motif of amino acids could accurately predict ivermectin binding site for other ligand gated channels. Here, we will review what is currently known about ivermectin binding and modulation of Cys-loop receptor family of ligand-gated ion channels and what are the critical structur al determinants underlying potentiation of the P2X4 receptor channel., H. Zemkova ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
566. Allostery and Cooperativity in the Interaction of Drugs with Ionic Channel Receptors
- Creator:
- Krůšek, J.
- Type:
- article, model:article, and TEXT
- Subject:
- Allostery, Cooperativity, Hill coefficient, Affinity, Efficacy, and Nicotinic acetylcholine receptor
- Language:
- English
- Description:
- Allostery is an essential property of many physiological mechanisms. Cooperativity together with allostery is observed in the behavior of multisubunit receptors. Here we summarize and compare several approaches to the description and analysis of allosteric phenomena with emphasis on the receptors connected to ionic channels as a model. Several simplified methods are discussed in comparison with the microscopic kinetic scheme, affinity-efficacy separation and a thermodynamic approach.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
567. Alloxan in vivo does not only exert deleterious effects on pancreatic B cells
- Creator:
- Szkudelski, T., Kandulska, K., and Okulicz, M.
- Type:
- article, model:article, and TEXT
- Subject:
- alloxan, glucose, insulin, sulfhydryl groups, and glutathione peroxidase
- Language:
- English
- Description:
- The aim of the experiment was to investigate the mechanism of harmful alloxan action in vivo. 75 mg/kg b.w. of this diabetogenic agent were administered to fasting rats. Two minutes later the animals were decapitated. It was observed that alloxan caused a distinct rise in blood insulin and glucose levels with a concomitant drop of free fatty acids. The amount of sulfhydryl groups in the liver of alloxan-treated rats was decreased and glutathione peroxidase activity was substantially higher. These results indicate that some changes observed in alloxan-induced diabetes can not only be the consequence of B cells damage by alloxan but may also be the result of its direct influence on other tissues. It was also observed that glucose given 20 min before alloxan injection only partially protected against the deleterious effects of alloxan.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
568. Almost log-optimal trading strategies for small transaction costs in model with stochastic coefficients
- Creator:
- Dostál, Petr
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- small transaction costs, logarithmic utility function, and non-constant coefficients
- Language:
- English
- Description:
- We consider a non-consuming agent investing in a stock and a money market interested in the portfolio market price far in the future. We derive a strategy which is almost log-optimal in the long run in the presence of small proportional transaction costs for the case when the rate of return and the volatility of the stock market price are bounded It\^o processes with bounded coefficients and when the volatility is bounded away from zero.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
569. Alpha2-adrenoceptor control of ion and water transport in the newt renal distal tubule
- Creator:
- Goncharevskaya, O. A. and Monin, Yu. G.
- Type:
- article, model:article, and TEXT
- Subject:
- norepinephrine, dibenamine, propranolol, idazoxan, prazosin, distal tubule, and electrolytes
- Language:
- English
- Description:
- To study the nature of adrenergic stimulation of ions and water reabsorption in the newt renal distal tubule, stationary microperfusion of the nephron and electron probe analysis were used. After application of norepinephrine (NE 10'6 M) to the tubule surface, the fractional reabsorption of fluid increased from 15.0±3.1 to 41.30±10.4 % (n = 7, p<0.01), of Na+ from 69.30 ±6.6 to 79.10±7.5 % (p<0.05), CT from 63.30±7.6 to 72.40 ±7.9 % (p<0.05). Instead of secretion (control), there was reabsorption of K+. Fractional reabsorption of Ca2+ decreased from 51.00±6.0 to 43.00±7.0 % (p<0.05). The nonspecific alpha-adrenergic antagonist dibenamine 10"6 M completely inhibited the effect of NE while, under the action of propranolol (2xl(76 M) NE increased ion and water reabsorption significantly. When applied alone, or with NE, the specific alpha2-adrenoblocker idazoxan, 2xl0‘6 M, did not interfere with reabsorption in the distal tubule. At the same time, under the action of alphai-adrenoblocker prazosin 2xl0'6 M NE, increased the fractional reabsorption of fluid from 24.10 ±3.4 to 44.40 ±4.0 % (n = 6, p<0.001). These results serve as evidence that there exist specific alpha^adrenoceptors in the newt distal tubule the stimulation of which increases membrane permeability of the distal tubule to water, Na+, K+, Cl', but not to Ca2+.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
570. Alterations in Calcium Homeostasis as Biological Marker for Mild Alzheimer´s Disease?
- Creator:
- Řípová, D., Platilová, V., Strunecká, A., Jirák, |R., and Höschl, C.
- Type:
- article, model:article, and TEXT
- Subject:
- Alzheimer's disease, Vascular dementia, Platelets, Calcium homeostasis, and Biological marker
- Language:
- English
- Description:
- The calcium hypothesis of neurodegenerative disorders such as Alzheimer´s disease (AD) suggests that altered cytosolic Ca2+ levels ([Ca2+]i) and/or disturbances in Ca2+ homeostasis concern cellular mechanisms underlying neuronal pathology. To search for a diagnostic marker of Alzheimer´s disease, we measured cytosolic calcium concentrations in platelets of AD patients, age-matched control subjects (AMC), and vascular dementia (VD) patients. The ([Ca2+]i) was determined using long wavelength indicator Fluo-3AM in 21 mild AD patients, 17 AMC, and 23 patients with VD. The basal values of [Ca2+]i were significantly lower in AD compared to AMC. After the addition of 1 mM calcium, the [Ca2+]i markedly increased in platelets of AD compared to AMC and VD. Measurement of calcium homeostasis could provide a very sensitive, but less specific biological marker of AD. These results support the hypothesis that influencing calcium homeostasis may provide a therapeutic strategy in dementia.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public