排序方式: 共有19条查询结果,搜索用时 15 毫秒
11.
Rafael Rodriguez-Mercado Gregory D Ford Zhenfeng Xu Edmundo N Kraiselburd Melween I Martinez Vesna A Eterovi? Edgar Colon Idia V Rodriguez Peter Portilla Pedro A Ferchmin Lynette Gierbolini Maria Rodriguez-Carrasquillo Michael D Powell John VK Pulliam Casey O McCraw Alicia Gates Byron D Ford 《Comparative medicine》2012,62(5):427-438
The goal of this study was to characterize acute neuronal injury in a novel nonhuman primate (NHP) ischemic stroke model by using multiple outcome measures. Silk sutures were inserted into the M1 segment of the middle cerebral artery of rhesus macaques to achieve permanent occlusion of the vessel. The sutures were introduced via the femoral artery by using endovascular microcatheterization techniques. Within hours after middle cerebral artery occlusion (MCAO), infarction was detectable by using diffusion-weighted MRI imaging. The infarcts expanded by 24 h after MCAO and then were detectable on T2-weighted images. The infarcts seen by MRI were consistent with neuronal injury demonstrated histologically. Neurobehavioral function after MCAO was determined by using 2 neurologic testing scales. Neurologic assessments indicated that impairment after ischemia was limited to motor function in the contralateral arm; other neurologic and behavioral parameters were largely unaffected. We also used microarrays to examine gene expression profiles in peripheral blood mononuclear cells after MCAO-induced ischemia. Several genes were altered in a time-dependent manner after MCAO, suggesting that this ischemia model may be suitable for identifying blood biomarkers associated with the presence and severity of ischemia. This NHP stroke model likely will facilitate the elucidation of mechanisms associated with acute neuronal injury after ischemia. In addition, the ability to identify candidate blood biomarkers in NHP after ischemia may prompt the development of new strategies for the diagnosis and treatment of ischemic stroke in humans.Abbreviations: MCAO, middle cerebral artery occlusion; NHP, nonhuman primate; PBMC, peripheral blood mononuclear cellsStroke is a debilitating neurologic condition, and little progress has been made in the development of neuroprotective treatments for acute stroke. The Stroke Therapy Academic Industry Roundtable (STAIR) report suggested that preclinical candidates for stroke therapy should be validated by testing in large animals with similarities to humans, such as nonhuman primates (NHP).26 NHP stroke models have been developed in several species, including rhesus monkeys, marmosets, and baboons, by using a variety of techniques for middle cerebral artery occlusion (MCAO).4,10,12,13,14,25,32 The rhesus macaque is ideal for stroke studies because of its structural similarities to human brain. The rhesus brain is gyrencephalic, which makes it preferable to those of lissencephalic primates (for example, marmosets) and is functionally similar to human brain.6 In addition, the immunologic profile of rhesus macaques is similar to that of humans; therefore these animals are the preferred model for the study of immune responses to infectious diseases such as HIV/SIV, Dengue virus, and others.17,23,30In addition to their use for neuroprotection assessment, NHP stroke models can facilitate efforts to develop diagnostic tools for identifying and treating stroke symptoms. The use of genomics in peripheral blood cells has been shown to be an excellent method to identify candidate biomarkers and cellular mechanisms associated with stroke.28,29 Blood biomarkers can be used to rapidly determine the occurrence, timing, subtype, and severity of stroke.11,15 One possible reason for the lack of viable stroke biomarkers may be the research models used to search for these markers. Although rodent stroke models have yielded a wealth of information on the mechanisms associated with brain ischemia, the findings have not translated well to human clinical trials.26 Recent studies in human patients showed promising results when genomic tools have been used to screen for novel stroke biomarkers.3,16,27 However, validation of human studies is limited by the need for large data sets in light of heterogeneity in stroke onset, subtype, comorbidities, and other factors. In addition, it is also impossible to know the exact time of stroke onset in most patients.Here we characterized acute neuronal injury in a novel, minimally invasive permanent ischemic stroke model involving rhesus macaques. Using endovascular catheterization techniques, we introduced silk sutures into the M1 segment of the middle cerebral artery and permanently occluded it. This procedure reliably produced infarcts that could be measured by MRI of the macaque brains during the acute phase period. The procedure resulted in discrete and limited neurobehavioral deficits, indicating the potential of this stroke model for chronic neuroprotection studies in the future. In addition, we used microarrays to identify blood genomic profiles that were altered in a time-dependent manner after ischemia. These studies characterize a preclinical model that is suitable for elucidating the mechanisms associated with cerebral ischemia and that may aid in identifying strategies for the diagnosis and treatment of stroke in humans. 相似文献
12.
13.
Background
A large number of microsatellites have been extensively used to comprehend the genetic diversity of different global groups. This paper entails polymorphism at 15 STR in four predominant and endogamous populations representing Karnataka, located on the southwest coast of India. The populations residing in this region are believed to have received gene flow from south Indian populations and world migrants, hence, we carried out a detailed study on populations inhabiting this region to understand their genetic structure, diversity related to geography and linguistic affiliation and relatedness to other Indian and global migrant populations. 相似文献14.
Genome resource banks (GRBs) and assisted reproductive techniques are increasingly recognized as useful tools for the management and conservation of biodiversity, including endangered species. Cryotechnology permits long-term storage of valuable genetic material. Although, the actual application to endangered species management requires technical knowledge about sperm freezing and thawing, a systematic understanding of the quantitative impacts of various germ plasm storage and use scenarios is also mandatory. In this study, various GRB strategies were analyzed using the historical data from three managed populations of endangered species with varied pedigrees (Eld's deer, Przewalski's horse, and Sumatran tiger). The following types of sperm banks were assessed: (1) a "Wild Bank" consisting of sperm (i.e., genes) from 5 to 10 males unrelated to the managed population and to each other; and (2) a "Best Male" bank containing sperm from only the most genetically valuable males alive in the ex situ population at the time the bank was established. These different bank types were then used to evaluate the effectiveness of different bank usage frequencies. The efficiency of each scenario was assessed by examining the level of inbreeding and gene diversity in the population. Overall, a sperm usage frequency of five times per year was determined to be the most efficient and "wild banks" were highly successful at enhancing genetic diversity. The value of a GRB established from the ex situ population depends on how closely related the banked males are to future generations. A GRB will have significantly less benefit when banked males also produce many successful offspring, or when donors are already genetically over-represented in the population at the time of establishing the GRB. 相似文献
15.
Shomu Bohora Narayanan Namboodiri Santosh Dora VK Ajit Kumar Jaganmohan Tharakan 《Indian pacing and electrophysiology journal》2010,10(1):62-66
Mahaim Fiber tachycardia characteristically causes a wide QRS tachycardia with left bundle branch morphology and left axis deviation, especially in young patients, having no structural heart disease. Mahaim fiber automaticity further cements the proposition of Mahaim fiber, due to its Atrioventricular (AV) node like property, being called as an ectopic AV node. 相似文献
16.
VK Satya R Radhajeyalakshmi K Kavitha V Paranidharan R Bhaskaran 《Archives Of Phytopathology And Plant Protection》2013,46(3):185-192
The fungitoxic effect of various medicinal plants belonging to different families was evaluated in vitro on Rhizoctonia solani, the rice sheath blight pathogen. Of the various plant extracts, the leaf extract of zimmu (Allium cepa × Allium sativum) showed the maximum antifungal activity against R. solani and recorded an inhibition zone of 12?mm. The leaf extract of zimmu was also effective in inhibiting the growth of other agronomically important fungal and bacterial pathogens viz., Aspergillus flavus, Curvularia lunata, Alternaria solani, Xanthomonas oryzae pv. oryzae, Xanthomonas campestris pv. malvacearum and Xanthomonas axonopodis pv. citri. The antimicrobial compound was dissoluble in methanol and the methanolic extract showed the absorption maxima at 210?nm and 230?nm. Phenolic compounds were present in greater amounts in methanol extract of zimmu. TLC analysis showed the appearance of two blue spots at R f ?=?0.65 and R f ?=?0.90. The compounds eluted at R f ?=?0.65 and R f ?=?0.90 by preparative TLC exhibited strong antifungal activity against R. solani. 相似文献
17.
Abjal Pasha Shaik Abbas H Alsaeed S Kiranmayee VK Bammidi Asma Sultana 《Bioinformation》2013,9(1):29-36
Cubilin, (CUBN; also known as intrinsic factor-cobalamin receptor [Homo sapiens Entrez Pubmed ref ; NM_001081.3;
GI: 119606627]), located in the epithelium of intestine and kidney acts as a receptor for intrinsic factor – vitamin B12 complexes.
Mutations in CUBN may play a role in autosomal recessive megaloblastic anemia. The current study investigated the possible role
of CUBN in evolution using phylogenetic testing. A total of 588 BLAST hits were found for the cubilin query sequence and these
hits showed putative conserved domain, CUB superfamily (as on 27th Nov 2012). A first-pass phylogenetic tree was constructed to
identify the taxa which most often contained the CUBN sequences. Following this, we narrowed down the search by manually
deleting sequences which were not CUBN. A repeat phylogenetic analysis of 25 taxa was performed using PhyML, RAxML and
TreeDyn softwares to confirm that CUBN is a conserved protein emphasizing its importance as an extracellular domain and being
present in proteins mostly known to be involved in development in many chordate taxa but not found in prokaryotes, plants and
yeast.. No horizontal gene transfers have been found between different taxa. NG_008967.1相似文献
18.
Background
In the internal fixation of fractured bone by means of bone-plates fastened to the bone on its tensile surface, an on-going concern has been the excessive stress-shielding of the bone by the excessively-stiff stainless-steel plate. The compressive stress-shielding at the fracture-interface immediately after fracture-fixation delays callus formation and bone healing. Likewise, the tensile stress-shielding of the layer of the bone underneath the plate can cause osteoporosis and decrease in tensile strength of this layer. 相似文献19.
Revathi?Rajkumar Jheelam?Banerjee Hima?Bindu?Gunturi R?Trivedi VK?KashyapEmail author 《BMC evolutionary biology》2005,5(1):26