排序方式: 共有36条查询结果,搜索用时 0 毫秒
1.
A low-threshold fast inactivating K+ current (I(Alth)) was recorded in isolated land snail neurons using the two-microelectrode voltage clamp method. A nootropic drug, vinpocetine, applied to the extracellular medium at a concentration of 1-100 microM potentiated I(Alth). The potentiation consisted in a rise of its peak amplitude and an increase of the half-decay time. Vinpocetine did not cause a shift of the steady-state activation and inactivation curves along the potential axis. Dibutyryl cyclic GMP (dcGMP) also increased the peak amplitude but did not change the time of current half-decay. dcAMP did not potentiate I(Alth). The possible role of K+-current potentiation in neuronal membranes in therapy of dementia is discussed. 相似文献
2.
JI Priego AG Lucas-Cuevas I Aparicio JV Giménez JM Cortell-Tormo P Pérez-Soriano 《Biology of sport / Institute of Sport》2015,32(3):219-223
The use of graduated compression stockings (GCS) in sport has been increasing in the last years due to their potential positive effects for athletes. However, there is little evidence to support whether these types of garments actually improve cardiorespiratory performance. The aim of this study was to examine the cardiorespiratory responses of GCS during running after three weeks of regular use. Twenty recreational runners performed three tests on different days: test 1) – a 5-min maximal effort run in order to determine the participants’ maximal aerobic speed; and tests 2) and 3) – a fatigue running test of 30 minutes at 80% of their maximal aerobic speed with either GCS or PLACEBO stockings at random. Cardiorespiratory parameters (minute ventilation, heart rate, relative oxygen consumption, relative carbon dioxide production, ventilatory equivalents for oxygen and carbon dioxide, and oxygen pulse) were measured. Before each test in the laboratory, the participants trained with the randomly assigned stockings (GCS or PLACEBO) for three weeks. No significant differences between GCS and PLACEBO were found in any of the cardiorespiratory parameters. In conclusion, the present study provides evidence that running with GCS for three weeks does not influence cardiorespiratory parameters in recreational runners. 相似文献
3.
Beste DJ Hooper T Stewart G Bonde B Avignone-Rossa C Bushell ME Wheeler P Klamt S Kierzek AM McFadden J 《Genome biology》2007,8(5):R89
Background
An impediment to the rational development of novel drugs against tuberculosis (TB) is a general paucity of knowledge concerning the metabolism of Mycobacterium tuberculosis, particularly during infection. Constraint-based modeling provides a novel approach to investigating microbial metabolism but has not yet been applied to genome-scale modeling of M. tuberculosis. 相似文献4.
Evidence for selection on synonymous mutations affecting stability of mRNA secondary structure in mammals 下载免费PDF全文
Background
In mammals, contrary to what is usually assumed, recent evidence suggests that synonymous mutations may not be selectively neutral. This position has proven contentious, not least because of the absence of a viable mechanism. Here we test whether synonymous mutations might be under selection owing to their effects on the thermodynamic stability of mRNA, mediated by changes in secondary structure. 相似文献5.
CTS Silva V. Wanderley-Teixeira FM Cunha JV Oliveira KA Dutra DMA Ferraz Navarro 《Biotechnic & histochemistry》2018,93(1):36-48
The armyworm, Spodoptera frugiperda, is the principal pest of corn in Brazil. Control is achieved primarily by synthetic insecticides, which cause problems for the agro-ecosystem. Alternative methods of control are under investigation and citronella (Cymbopogon winterianus) essential oil appears to be a promising agent. We investigated the effects of citronella oil using histological, histochemical and immunohistochemical methods. The midgut of larvae treated with citronella exhibited altered epithelium including cytoplasmic protrusions, columnar cell extrusion, pyknotic nuclei, and increased periodic acid-Schiff positive granules. Regenerative cells in the epithelium of the midgut increased in number, which facilitated subsequent regeneration of this tissue. After exposure to citronella, trophocytes, the principal cell type of the fat body, possessed enlarged vacuoles and mitotic bodies, and contained reduced amounts of glycogen, lipid, and protein. Citronella oil caused morphological changes of the midgut and reduction of stored resources in the fat body, which may adversely affect insect reproduction and survival. 相似文献
6.
糖尿病微血管病变严重影响了患者生活质量,是患者致死致残主要原因。微血管病变主要表现在视网膜、肾、神经、心肌组织。微血管病变的机制尚未完全清楚,近年越来越多研究发现血管内皮祖细胞(endothelial progenitor cells,EPCs)是该病发病重要原因。EPCs有分化为成熟的内皮细胞并且参与新血管形成和新生的能力。正常情况下内皮损失和EPCs对内皮的修复作用处于动态平衡状态,一旦EPCs受损,内皮损害和修复之间的平衡被打破,内皮层的完整性遭到破坏,必然参与糖尿病血管病变的发生发展。国内外大量研究证明糖尿病合并大血管病变EPCs数目功能改变,而糖尿病合并微血管病变EPCs的怎样变化?本文就EPCs与糖尿病微血管病变的关系进行系统综述。 相似文献
7.
M Montenegro S Llambí G Castro N Barlocco A Vadell V Landi JV Delgado A Martínez 《Genetics and molecular biology》2015,38(1):48-54
In this study, we genetically characterized the Uruguayan pig breed Pampa Rocha.
Genetic variability was assessed by analyzing a panel of 25 microsatellite markers
from a sample of 39 individuals. Pampa Rocha pigs showed high genetic variability
with observed and expected heterozygosities of 0.583 and 0.603, respectively. The
mean number of alleles was 5.72. Twenty-four markers were polymorphic, with 95.8% of
them in Hardy Weinberg equilibrium. The level of endogamy was low (FIS =
0.0475). A factorial analysis of correspondence was used to assess the genetic
differences between Pampa Rocha and other pig breeds; genetic distances were
calculated, and a tree was designed to reflect the distance matrix. Individuals were
also allocated into clusters. This analysis showed that the Pampa Rocha breed was
separated from the other breeds along the first and second axes. The
neighbour-joining tree generated by the genetic distances DA showed
clustering of Pampa Rocha with the Meishan breed. The allocation of individuals to
clusters showed a clear separation of Pampa Rocha pigs. These results provide
insights into the genetic variability of Pampa Rocha pigs and indicate that this
breed is a well-defined genetic entity. 相似文献
8.
TJS Alves GS Cruz V Wanderley-Teixeira AAC Teixeira JV Oliveira AA Correia 《Biotechnic & histochemistry》2014,89(4):245-255
The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), not only damages crops, but controlling its population also requires synthetic insecticides, which leads to selection of resistant populations and environmental contamination. Essential oils are an alternative for controlling this insect. There are few studies of the effects of these oils on the insect's reproductive system. We evaluated the effects of the long pepper, Piper hispidinervum, essential oil on the gonads of the armyworm and tested its possible influence on the fertility of this insect. Dosages of 30 and 50 mg/ml were tested in 3rd instar caterpillars using the leaf immersion method. Testes and ovarioles were collected, fixed with 10% formalin and embedded in Historesin. The sections were stained with toluidine blue and Mallory trichrome to detect connective tissue, periodic acid-Schiff to detect neutral carbohydrates, and bromophenol blue to detect proteins. We found that the long pepper essential oil affected negatively the spermatogenesis and altered the histochemistry of the ovarioles of S. frugiperda. The effects of long pepper oil suggest that it is a promising tool for controlling the armyworm pest. 相似文献
9.
Kapai NA Bukanova JV Solntseva EI Skrebitsky VG 《Cellular and molecular neurobiology》2012,32(2):219-226
Acetylcholinesterase (AChE) inhibitor donepezil is widely used for the treatment of Alzheimer’s disease (AD). The mechanisms
of therapeutic effects of the drug are not well understood. The ability of donepezil to reverse a known pathogenic effect
of β-amyloid peptide (Abeta), namely, the impairment of hippocampal long-term potentiation (LTP), was not studied yet. The
goal of the present study was to study the influence of donepezil in 0.1–10 μM concentrations on control and Abeta-impaired
hippocampal LTP. Possible involvement of N-methyl-d-aspartate receptors (NMDARs) into mechanisms of donepezil action was also studied. LTP of population spike (PS) was studied
in the CA1 region of rat hippocampal slices. Change of LTP by donepezil treatment had a bell-shaped dose–response curve. The
drug in concentrations of 0.1 and 1 μM did not change LTP while in concentration of 0.5 μM significantly increased it, and
in concentration of 5 and 10 μM suppressed LTP partially or completely. Abeta (200 nM) markedly suppressed LTP. Addition of
0.1, 0.5 or 1 μM donepezil to Abeta solution caused a restoration of LTP. N-methyl-d-aspartate (NMDA) currents were studied in acutely isolated pyramidal neurons from CA1 region of rat hippocampus. Neither
Abeta, nor 0.5 μM donepezil were found to change NMDA currents, while 10 μM donepezil rapidly and reversibly depressed it.
Results suggest that donepezil augments control and impaired by Abeta hippocampal LTP in NMDAR-independent manner. In general,
our findings extend the understanding of mechanisms of therapeutic action of donepezil, especially at an early stage of AD,
and maybe taken into account while considering the possibility of donepezil overdose. 相似文献