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1.
Eight days of September 1985 were spent in a Swiss high-altitude meteorological station. The main facts apparent in this study at the end of summer are a great cold, with a long duration of below zero; sometimes, a severe dryness, decreasing to 1% of relstive humidity but also nearing 99%; a very high wind, blowing to 17 m/s at the maximum; and a considerable variability of these parameters in a very short time. A comparison is made with two nearby, lower altitude stations. The consequences for human confort are also considered.  相似文献   

2.
Although the mechanism of electroconvulsive therapy (ECT) is not clearly known, its effects on hormones have been widely studied. However, there are controversies about the effect of ECT on blood glucose level. In addition, the possible effects of ECT on the blood cholesterol, LDL, HDL, and triglyceride levels are ignored research areas.  相似文献   

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The introduction of chlorpromazine in Belgium and the Netherlands demonstrates an intriguing tango between old and new treatments. Chlorpromazine, marketed by the French company Rhône Poulenc entered psychiatry as an adjunct to existing therapies. Instead of promoting chlorpromazine as a revolutionary therapy, we see early efforts to market Largactil as a supplement to the armoury of psychiatric treatments. These marketing efforts matched the idiosyncrasies of national and local styles and cultures. Despite continuities with earlier therapeutic developments, we support the notion of a therapeutic revolution. In the early sixties supply and demand provoked a turn towards more standardized therapeutic regimes.  相似文献   

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Interactions between potentially mutualistic partners can vary over geographic areas. Myrmecophytes, which are plants harbouring ants, often do not exhibit sufficient intraspecific variability to permit comparative studies of myrmecophytic traits over space or time. Humboldtia brunonis (Fabaceae), a dominant, endemic myrmecophyte of the Indian Western Ghats, is unique in exhibiting considerable variability in myrmecophytic traits, e.g. domatia presence, as well as domatia occupancy and associated ant diversity throughout its geographic range. Although its caulinary domatia are occupied by at least 16 ant species throughout its distribution, young leaves and floral buds producing extrafloral nectar (EFN) are protected by ants from herbivory only in the southernmost region, where Technomyrmex albipes (Dolichoderinae) is the most abundant ant species. The extent of protection by ants was positively related to local species richness of ants and their occupancy of domatia. On the other hand, the highest abundance of interlopers in the domatia, including non‐protective ants, the arboreal earthworm Perionyx pullus, and other invertebrates, occurred in sites with the least protection from herbivory by ants. Whereas domatia morphometry did not vary between sites, domatia occupied by protective ants and invertebrate interlopers were longer and broader than empty ones at all sites. The lowest percentage of empty domatia was found at the southernmost site. There was a progressive decline in ant species richness from that found at the sites, to that feeding on H. brunonis EFN, to that occupying domatia, possibly indicating constraints in the interactions with the plants at various levels. Our study of this dominant myrmecophyte emphasizes the impact of local factors such as the availability of suitable ant partners, domatia occupancy, and the presence of interlopers on the emergence of a protection mutualism between ants and plants. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 538–551.  相似文献   

7.
Making an inference on the absence of a species in a site is often problematic, due to detection probability being, in most cases, <1. Inference is more complicated if detection probability, together with distribution patterns, vary during the year, since the possibility of inferring a species absence, at reasonable costs, may be possible only in certain periods. Our aim here is to show how such challenging situations can be by tackled by applying some recently developed occupancy models combined with sample size (number of repeated surveys) estimation. We thus analysed the distribution of two rodents Myodes glareolus and Mus musculus domesticus in a fragmented landscape in central Italy pointing out how it is possible to identify true absences, non-detections, extinctions/colonizations and determine seasonal values of detection probability.  相似文献   

8.
Paramutation is the transfer of epigenetic information between alleles that leads to a heritable change in expression of one of these alleles. Paramutation at the tissue‐specifically expressed maize (Zea mays) b1 locus involves the low‐expressing B′ and high‐expressing B‐I allele. Combined in the same nucleus, B′ heritably changes B‐I into B′. A hepta‐repeat located 100‐kb upstream of the b1 coding region is required for paramutation and for high b1 expression. The role of epigenetic modifications in paramutation is currently not well understood. In this study, we show that the B′ hepta‐repeat is DNA‐hypermethylated in all tissues analyzed. Importantly, combining B′ and B‐I in one nucleus results in de novo methylation of the B‐I repeats early in plant development. These findings indicate a role for hepta‐repeat DNA methylation in the establishment and maintenance of the silenced B′ state. In contrast, nucleosome occupancy, H3 acetylation, and H3K9 and H3K27 methylation are mainly involved in tissue‐specific regulation of the hepta‐repeat. Nucleosome depletion and H3 acetylation are tissue‐specifically regulated at the B‐I hepta‐repeat and associated with enhancement of b1 expression. H3K9 and H3K27 methylation are tissue‐specifically localized at the B′ hepta‐repeat and reinforce the silenced B′ chromatin state. The B′ coding region is H3K27 dimethylated in all tissues analyzed, indicating a role in the maintenance of the silenced B′ state. Taken together, these findings provide insight into the mechanisms underlying paramutation and tissue‐specific regulation of b1 at the level of chromatin structure.  相似文献   

9.
Abstract

Unbound drug concentration in the brain would be the true exposure responsible for specific target occupancy. Drug exposures from preclinical are total concentrations of those over/underestimate the clinical dose projection. With the application of mass spectrometry, the current work proposes a definite measure of test drug exposures at serotonin-2A occupancy. The 5-HT2A occupancy of antagonist in the rat brain has determined with non-radiolabeled tracer MDL-100,907 at an optimized dose (3?µg/kg) and treatment time (30?min). Equilibrium dialysis method determines the in vitro free fraction of the test antagonist in untreated rat brain homogenates and plasma. Drug-free fractions derived the unbound concentration (EC50) in plasma and brain at test doses. The corresponding binding affinities (Ki) correlated with the unbound concentrations. Except for quetiapine, the ED50 values in the dose-occupancy curves of antagonists are close and ranged from 1 to 3?mg/kg. The test drug quetiapine, eplivanserin, and clozapine showed high free fractions in plasma, but for ketanserin and olanzapine, the brain free fraction was higher. The correlation between the unbound EC50 of the antagonists and corresponding Ki values was good (r2=0.828). The improved EC50 accuracy with unbound concentrations was 10–250 folds in plasma and 10–170 folds in the brain. Further, the free fractions (fu, plasma/fu, brain) of test drugs had shown a correlation of ~83% with brain permeability (Ctotal brain/Ctotal plasma), a limiting factor. Thus, correlating the occupancy with unbound exposure and pharmacology would result in an accurate measurement of drug potency and optimizes in selecting the clinical dose.  相似文献   

10.
In this paper I claim that the goal of mapping and sequencing the human genome is not wholly new, but rather is an extension of an older project to map genes, a central aim of genetics since its birth. Thus, the discussion about the value of the HGP should not be posed in global terms of acceptance or rejection, but in terms of how it should be developed. The first section of this paper presents a brief history of the project. The second section distinguishes among four kinds of issues relevant to an evaluation of the HGP: those economic and organizational issues related to the feasibility of the project; the ethical questions arising in the development of the project and the application of the data gathered; the empirical issues relevant to the scientific value of the project; and conceptual issues like reductionism and determinism relevant to understand the nature and scope of the project. In a third section, I analyze in detail whether the HGP and, more generally, molecular biology is reductionistic.  相似文献   

11.
Stomach contents of 242 brown trout, 1440 minnow and 368 stickleback from the North Lake and of 121 trout, 1079 minnow and 332 stickleback from the South Lake of an upland reservoir system in Co. Wicklow (Ireland) were analysed.Macroinvertebrates from each reservoir were sampled in September 1982, June and September 1983, and June 1984. A further sampling in September 1984 involved only the South Lake as low water levels prevented littoral samples being taken in the North Lake. Vertical and horizontal hauls of zooplankton were also collected during September 1983 and 1984.The diets of the three species were compared on each date using Spearman Rank Correlation coefficients and Schoener's index of dietary overlap. The diets of the minnow and stickleback regularly showed significant correlation but the trout diet was very different except during periods of very reduced water levels when all species fed on zooplankton.  相似文献   

12.
摘要 目的:探讨与分析人参皂苷Rg1对抑郁症大鼠抑郁行为和海马神经元损伤、蛋白激酶A(PKA)与蛋白激酶C(PKC)的影响。方法:抑郁症大鼠48只随机平分为三组-模型组、实验1组、实验2组,每组16只大鼠。实验1组、实验2组每天2次灌胃给药(1 mg/mL、4 mg/mL人参皂苷Rg1),给药体积为10 mL;模型组以相同方式按体重给予双蒸水。观察与记录鼠抑郁行为和海马神经元损伤、PKA、PKC表达变化情况。结果:实验1组、实验2组治疗第7 d、第14 d的逃避潜伏期都显著低于模型组,实验2组与实验1组相比也显著缩短(P<0.05)。实验1组、实验2组治疗第7 d、第14 d的糖水偏好率高于模型组,实验2组与实验1组相比也显著升高(P<0.05)。实验1组、实验2组治疗第7 d、第14 d的血清5-羟色胺较模型组高,血清皮质酮含量较模型组低,实验2组与实验1组对比也有明显差异(P<0.05)。实验1组、实验2组治疗第7 d、第14 d的海马神经元组织的PKA、PKC蛋白相对表达水平显著低于模型组,实验2组与实验1组相比也显著缩短(P<0.05)。结论:人参皂苷Rg1在抑郁症大鼠的应用能改善抑郁行为,增加糖水偏好率,降低逃避潜伏期,还可提高大鼠的血清5-羟色胺含量,降低血清皮质酮含量,降低海马神经元组织的PKA、PKC蛋白表达水平。  相似文献   

13.
Summary Using Southern and in situ hybridization analyses, we have earlier defined four different subfamilies of alpha satellite DNA (designated pTRA-1, -2, -4, and -7), each of which has a unique higher order structure represented almost identically on human chromosomes 13, 14, and 21. Here we present the complete sequence of single isolates of these four subfamilies, representing approximately 12 kb of sequence information. Sequences of the individual 171-bp monomers that constitute these four subfamilies (and a fifth subfamily, Alpha-R1, that is known to be present on chromosomes 13 and 21) were compared both within and between the different clones. The results indicate that, at the level of their primary sequence, the five alpha subfamilies are characterized by structures that are as unrelated to each other as the different alpha subfamilies from other chromosomes. However, sequence comparisons between monomers of these clones indicate the possibility that pTRA-2, -4, and-1 may have arisen, at least in part, from a common ancestral alphoid sequence. We also provide evidence that exchange of pTRA-1 between nonhomologous centromeres and its homogenization throughout the population, perhaps by unequal exchange mechanisms, could have occurred after the divergence of humans and chimpanzees. The evolution of multiple alphoid subfamilies within a single centromere suggests that unequal exchange mechanisms may be restricted to specific domains. This may in turn contribute to some requirement for subregional pairing of sequences along the length of the centromeres of these chromosomes. Offprint requests to: K.H.A. Choo  相似文献   

14.
Growth Hormone Releasing Hormone (GHRH) is one of the most important hormones in life. Because of its potential clinical importance, its short half-life, and its expensive chemical synthesis, an analog of hGHRH with a prolonged half-life and better activity has been studied for clinical application, especially for the treatment of muscle wasting, type II diabetes, or sleep disorders. The Pro-Pro-hGHRH(1-44) peptide has better activity. The fusion partner gene with 127 amino acid residues of the C-terminus from l-asparaginase was recombined with asp-pro-pro-hGHRH(1-44) gene synthesized by PCR method to form a fusion protein with the unique acid labile linker Asp-Pro. The recombinant protein was expressed to high levels in Escherichia coli BL21 (DE3). The Pro-Pro-hGHRH(1-44) peptide was purified to homogeneity by means of cell disruption, washing, ethanol precipitation, acid hydrolysis, and SP-Sephadex C-25, and Sephadex G-25 column chromatography. The fold of the purification was about 88 times and the yield was 1.1% of the total protein weight of the inclusion body. The peptide molecular mass of 5235.25 Da was determined by ESI mass spectroscopy. Its purity was determined by SDS-PAGE. In the study of the activity, we measured GH release of rat pituitary by using the antiserum kit against human GH. The peptide doses of 0.01, 0.1, 1.0, 7.72, and 20.9 microg/ml used, respectively, released the GH values of 0.1+/-0.1, 12.5+/-7.3, 16.6+/-5.8, 49.8+/-7.6, and 79.5+/-5.7 ng/ml whereas their blank controls, respectively, were 0.5+/-0.8, 4.1+/-2.6, 3.1+/-3.1, 4.7+/-1.8, and 1.2+/-0.3 ng/ml. The activity results of all dose groups except 0.01 microg/ml Pro-Pro-hGHRH(1-44) group and hGHRH(1-40) group showed that there were significant differences between GH released by the peptide and that by its blank control. With the increase of dosage, the differences were more significant. hGHRH(1-40) showed no measured GH release when the dose was up to 2 microg/ml. The activity results show that the Pro-Pro-hGHRH(1-44) peptide is a potential GH releasing analog.  相似文献   

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Guamerin, a canonical serine protease inhibitor from Hirudo nipponia, was identified as an elastase-specific inhibitor and has potential application in various diseases caused by elevated elastase concentration. However, the application of guamerin is limited because it also shows inhibitory activity against other proteases. To improve the selectivity of guamerin as an elastase inhibitor, it is essential to understand the binding mode of the inhibitor to elastase and to other proteases. For this purpose, we determined the crystal structure of guamerin in complex with chymotrypsin at 2.5 Å resolution. The binding mode of guamerin on elastase was explored from the model structure of guamerin/elastase. Guamerin binds to the hydrophobic pocket of the protease in a substrate-like manner using its binding loop. In order to improve the binding selectivity of guamerin to elastase, several residues in the binding loop were mutated and the inhibitory activities of the mutants against elastase and chymotrypsin were monitored. The substitution of the Met36 residue for Ala in the P1 site increased the inhibitory activity against elastase up to 14-fold, while the same mutant showed 7-fold decreased activity against chymotrypsin compared to the wild-type guamerin. Furthermore, the M36A guamerin mutant more effectively protected endothelial cells against cell damage caused by elastase than the wild-type guamerin.  相似文献   

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Using data from the newly available U.S. National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; Wave 3; n = 36,309), we evaluated relationships among gender, cigarette smoking status (current, former, non-smoker), life event stress (0-1 vs. 2+ events), and their impact on transitions in major depression diagnosis (MDD; new vs. absent cases; ongoing vs. remit cases). Women who were both current and former cigarette smokers with more than two stressful events had higher rates of new MDD diagnosis compared to men who were current or former smokers with two or more stressful events. Current smoking and experiencing two or more stressful events increased the odds of having an ongoing MDD diagnosis, while being a former smoker decreased these odds. Results suggest that smoking and stress are markers for depression risk in women and should help guide clinical assessment as well as gender-difference research on the biological underpinnings of these conditions.  相似文献   

20.
Environmental factors play an integral role, either directly or indirectly, in structuring faunal assemblages. Water chemistry, predation, hydroperiod and competition influence tadpole assemblages within waterbodies. We surveyed aquatic predators, habitat refugia, water height and water chemistry variables (pH, salinity and turbidity) at 37 waterbodies over an intensive 22‐day field survey to determine which environmental factors influence the relative abundance and occupancy of two habitat specialist anuran tadpole species in naturally acidic, oligotrophic waterbodies within eastern Australian wallum communities. The majority of tadpoles found were of Litoria olongburensis (wallum sedge frog) and Crinia tinnula (wallum froglet) species, both habitat specialists that are associated with wallum waterbodies and listed as Vulnerable under the IUCN Red List. Tadpoles of two other species (Litoria fallax (eastern sedge frog), and Litoria cooloolensis (cooloola sedge frog)) were recorded from two waterbodies. Tadpoles of Litoria gracilenta (graceful treefrog) were recorded from one waterbody. Relative abundance and occupancy of L. olongburensis tadpoles were associated with pH and water depth. Additionally, L. olongburensis tadpole relative abundance was negatively associated with turbidity. Waterbody occupancy by C. tinnula tadpoles was negatively associated with predatory fish and water depth and positively associated with turbidity. Variables associated with relative abundance of C. tinnula tadpoles were inconclusive and further survey work is required to identify these environmental factors. Our results show that the ecology of specialist and non‐specialist tadpole species associated with ‘unique’ (e.g. wallum) waterbodies is complex and species specific, with specialist species likely dominating unique habitats.  相似文献   

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