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951.
In order to define the ancestors of the Eurasian genera Axis and Rusa, the representatives of the tribe Pliocervini have been reviewed, with the exclusion of the genus Pliocervus. The fossil remains referred to Pliocervini stored in the Palaeontological Museum of Mechnikov Odessa National University and studied by Khomenko [Khomenko, I., 1913. Meotian fauna of v. Tarakliya of Bendery district. Annuaire géologique et minéralogique de la Russie. 1. The ancestors of modern and fossil Cervinae. 2. Giraffidae and Cavicornia 15, 107-132 (in Russian)] are reappraised: these remains are attributed to Cervavitus novorossiae (Khomenko, 1913). The fossil deer collected from the locality of Novoelizavetovka (Odessa region, Ukraine) and observed in the same Museum of the Odessa National University, is referred to Cervavitus variabilis Alexeev (1915).The fossil material from Shanxi and Honan provinces (China), described by Zdansky [Zdansky, O., 1925. Fossil Hirsche Chinas. Palaeontologia Sinica C 2, 1-94] and Teilhard de Chardin and Trassaert [Teilhard de Chardin, P., Trassaert, M., 1937. The Pliocene Camelidae, Giraffidae and Cervidae of southeastern Shansi.] is referred to Cervavitus shanxius Dong and Hu, 1994. The phylogenetic relationships between Pliocervini from China and the European ones are investigated on the basis of the morphological, biochronological and paleogeographical data. These elements and the suggestions of the more recent genetical and biometrical data may indicate that the origin of the two genera Axis and Rusa could be recognized into the Chinese pliocervines.  相似文献   
952.
953.
954.
Migraine is a complex disabling disease influenced mainly by age and gender during the life span. Neuroendocrine events related to reproductive stages and to the menstrual cycle may cause significant change in the clinical pattern of migraine over time, as a consequence of failure in adaptation higher in women than in men. Indeed, the individual threshold of vulnerability to manifest migraine is modulated by hormonal fluctuations naturally occurring throughout the menstrual cycle and at the time of reproductive transitions. In the present short review, the role of endogenous estrogen at the level of brain circuitries which are involved in multiple cellular, neurochemical and neurophysiological processes associated with migraine will be summarized in the context of reproductive milestones. In addition, some clues to recognize hormonally sensitive women on the basis of their migraine history, i.e. onset, association with menstruation or premenstrual syndrome, course during pregnancy and menopause, will be discussed in order to expand the knowledge of reproductive endocrinology in the management of migraine in women.  相似文献   
955.
In eukaryotes, RNA-binding proteins that contain multiple K homology (KH) domains play a key role in coordinating the different steps of RNA synthesis, metabolism and localization. Understanding how the different KH modules participate in the recognition of the RNA targets is necessary to dissect the way these proteins operate. We have designed a KH mutant with impaired RNA-binding capability for general use in exploring the role of individual KH domains in the combinatorial functional recognition of RNA targets. A double mutation in the hallmark GxxG loop (GxxG-to-GDDG) impairs nucleic acid binding without compromising the stability of the domain. We analysed the impact of the GDDG mutations in individual KH domains on the functional properties of KSRP as a prototype of multiple KH domain-containing proteins. We show how the GDDG mutant can be used to directly link biophysical information on the sequence specificity of the different KH domains of KSRP and their role in mRNA recognition and decay. This work defines a general molecular biology tool for the investigation of the function of individual KH domains in nucleic acid binding proteins.  相似文献   
956.
Abstract Alzheimer's disease is widely held to be associated with oxidative stress due, in part, to the membrane action of beta-amyloid peptide aggregates. Here, we studied the effect of cannabidiol, a major non-psychoactive component of the marijuana plant (Cannabis sativa) on beta-amyloid peptide-induced toxicity in cultured rat pheocromocytoma PC12 cells. Following exposure of cells to beta-amyloid peptide (1 micro g/mL), a marked reduction in cell survival was observed. This effect was associated with increased reactive oxygen species (ROS) production and lipid peroxidation, as well as caspase 3 (a key enzyme in the apoptosis cell-signalling cascade) appearance, DNA fragmentation and increased intracellular calcium. Treatment of the cells with cannabidiol (10(-7)-10(-4)m) prior to beta-amyloid peptide exposure significantly elevated cell survival while it decreased ROS production, lipid peroxidation, caspase 3 levels, DNA fragmentation and intracellular calcium. Our results indicate that cannabidiol exerts a combination of neuroprotective, anti-oxidative and anti-apoptotic effects against beta-amyloid peptide toxicity, and that inhibition of caspase 3 appearance from its inactive precursor, pro-caspase 3, by cannabidiol is involved in the signalling pathway for this neuroprotection.  相似文献   
957.
Mucins are high molecular weight epithelial proteins, strongly glycosylated, and are the main component of the mucus. Since mucus secretion can be altered in diseases, colon mucins can be regarded as a biomarker of chronic inflammatory bowel diseases or preneoplastic changes. Conventional histochemistry and lectin histochemistry combined with chemical treatment and enzymatic digestion were carried out to analyze the colon mucins in mice fed a high-fat diet for 25 weeks, a period sufficient to induce simple liver steatosis, to check whether the carbohydrate features of mucus can be altered by an inadequate diet. An increase in the sialo/sulfomucins ratio with respect to control mice, assessed by computerized image analysis, was observed in the colon, although differences in sialic acid acetylation between control and mice fed a high-fat diet were not found. High-fat diet was also associated with altered lectin-binding pattern of the mucus, with a probable shortening of oligosaccharide chains of glycoproteins. This pattern was leading to over-expression of Galβ1,3GalNAc terminal dimers (TF antigen) and GalNAc terminal residues (Tn antigen). This altered composition of mucins can be related to a defect in the process of glycosylation, or to incomplete maturation of goblet cells, and may be an early indication of preneoplastic and neoplastic changes. In conclusion, our findings confirm that a fatty-rich diet (Western-style diet) induces alteration of mucins and may be associated with colon diseases. Our investigation corroborates the usefulness of lectins histochemistry in the early diagnosis of prepathological states of the colon.  相似文献   
958.
959.
Pygmy populations occupy a vast territory extending west-to-east along the central African belt from the Congo Basin to Lake Victoria. However, their numbers and actual distribution is not known precisely. Here, we undertake this task by using locational data and population sizes for an unprecedented number of known Pygmy camps and settlements (n = 654) in five of the nine countries where currently distributed. With these data we develop spatial distribution models based on the favourability function, which distinguish areas with favourable environmental conditions from those less suitable for Pygmy presence. Highly favourable areas were significantly explained by presence of tropical forests, and by lower human pressure variables. For documented Pygmy settlements, we use the relationship between observed population sizes and predicted favourability values to estimate the total Pygmy population throughout Central Africa. We estimate that around 920,000 Pygmies (over 60% in DRC) is possible within favourable forest areas in Central Africa. We argue that fragmentation of the existing Pygmy populations, alongside pressure from extractive industries and sometimes conflict with conservation areas, endanger their future. There is an urgent need to inform policies that can mitigate against future external threats to these indigenous peoples’ culture and lifestyles.  相似文献   
960.
A procedure for analysis of melanin‐pigmented tissues based on alkaline hydrogen peroxide degradation coupled with high‐performance liquid chromatography (HPLC) ultraviolet determination of pyrrole‐2,3,5‐tricarboxylic acid (PTCA) for eumelanin and 6‐(2‐amino‐2‐carboxyethyl)‐2‐carboxy‐4‐hydroxybenzothiazole (BTCA) and 1,3‐thiazole‐2,4,5‐tricarboxylic acid for pheomelanin was recently developed. Despite advantages related to the degradation conditions and sample handling, a decrease of the reproducibility and resolution was observed after several chromatographic runs. We report herein an improved chromatographic methodology for simultaneous determination of PTCA and BTCA as representative markers of eumelanin and pheomelanin, respectively, based on the use of an octadecylsilane column with polar end‐capping with 1% formic acid (pH 2.8)/methanol as the eluant. The method requires conventional HPLC equipments and gives very good peak shapes and resolution, without need of ion pair reagents or high salt concentrations in the mobile phase. The intra‐assay precision of the analytical runs was satisfactory with CV values ≤4.0% (n = 5) for the two markers which did not exceed 8% after 50 consecutive injections on the column over 1 week. The peak area ratios at 254 and 280 nm (A280/A254: PTCA = 1.1, BTCA = 0.6) proved a valuable parameter for reliable identification of the structural markers even in the most complex degradation mixtures. The method can be applied to various eumelanin and pheomelanin pigmented tissues, including mammalian hair, skin and irides, and is amenable to be employed in population screening studies.  相似文献   
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