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排序方式: 共有5325条查询结果,搜索用时 15 毫秒
21.
22.
Frequency of cytokine polymorphisms in populations from western Europe,Africa, Asia,the Middle East and South America 总被引:15,自引:0,他引:15
Meenagh A Williams F Ross OA Patterson C Gorodezky C Hammond M Leheny WA Middleton D 《Human immunology》2002,63(11):1055-1061
PCR-SSOP identification procedures for IL-2, IL-6, IL-10, TNF-alpha and TNF-beta cytokine polymorphisms have been developed. Application of the procedures to a range of diverse geographically distributed populations has identified ethnic differences within the groups studied. Five populations were investigated, Northern Ireland, South African Zulu, Omani, Singapore Chinese and Mexican Mestizos. 相似文献
23.
Barrias CC Ribeiro CC Lamghari M Miranda CS Barbosa MA 《Journal of biomedical materials research. Part A》2005,72(1):57-66
In this study, the behavior of bone marrow stromal cells cultured on calcium titanium phosphate (CTP) microspheres was analyzed. Cell adhesion and proliferation were estimated by the neutral red assay and by total DNA quantification. Morphology and deposition of extracellular matrix were assessed by confocal laser scanning microscopy and/or scanning electron microscopy. The expression of the osteoblastic phenotype was evaluated by monitoring alkaline phosphatase activity and osteocalcin secretion. Results revealed that cells were able to attach and spread on the surface of CTP microspheres, and gradually grow into nearly confluent monolayers. Moreover, cells were able to bridge adjacent microspheres forming microsphere-cell clusters. Cells produced an abundant amount of fibrillar extracellular matrix that covered the substrate surface. Alkaline phosphatase activity peaked around days 7-14 and then decreased until day 21. Cells secreted osteocalcin, with higher levels being detected at day 14 than at day 21. Taken together, these results suggest that CTP microspheres are appropriate scaffolds for the growth and differentiation of cells along the osteoblastic lineage. 相似文献
24.
U2AF homology motifs: protein recognition in the RRM world 总被引:11,自引:0,他引:11
Recent structures of the heterodimeric splicing factor U2 snRNP auxiliary factor (U2AF) have revealed two unexpected examples of RNA recognition motif (RRM)-like domains with specialized features for protein recognition. These unusual RRMs, called U2AF homology motifs (UHMs), represent a novel class of protein recognition motifs. Defining a set of rules to distinguish traditional RRMs from UHMs is key to identifying novel UHM family members. Here we review the critical sequence features necessary to mediate protein-UHM interactions, and perform comprehensive database searches to identify new members of the UHM family. The resulting implications for the functional and evolutionary relationships among candidate UHM family members are discussed. 相似文献
25.
Merks JH van Karnebeek CD Caron HN Hennekam RC 《American journal of medical genetics. Part A》2003,(3):211-230
Clinical morphology has proved essential for the successful delineation of hundreds of syndromes and as a powerful instrument for detecting (candidate) genes (Gorlin et al. [2001]; Syndromes of the Head and Neck; Oxford: Oxford University Press. 1 p]. The major approach to reach this has been careful clinical evaluations of patients, focused on congenital anomalies. A similar careful physical examination performed in patients, who have been treated for childhood cancer, may allow detection of concurrent patterns of anomalies and provide clues for causative genes. In the past, several studies were performed describing the prevalence of anomalies in patients with cancer. However, in most studies, it was not possible to indicate the biologic relevance of the recorded anomalies, or to judge their relative importance. Are the detected anomalies common variants, and should they thus be regarded as normal, or are they minor anomalies or true abnormalities, indicating a possible developmental cause? Classification of items in the categories of common variants (disturbances of phenogenesis with a prevalence >4%), minor anomalies (disturbances of phenogenesis with a prevalence =4%), and malformations (disturbances of embryogenesis) should allow weighing the importance of the scored items in the population under study, and should facilitate assessment of developmental disturbances (if any) in a study group. The lack of published consensus in the literature led us to produce a classification list with a twofold goal. First, we wanted to enhance uniformity in the scoring and classification of apparently abnormal physical findings by a nomenclature for errors of morphogenesis detectable on surface examination, and secondly a uniform classification system. This should allow investigators to evaluate systematically the presence of patterns in phenotypic anomalies, in the general population, and in patients with various disorders, suspected to be a developmental anomaly. Also, normal values may be obtained this way. Second, the list will allow a determination of the importance of the collected symptoms in a study population. We tested the feasibility of the application of the classification list in a study population: the list was piloted in a group of patients who have had cancer as a child, to detect patterns of anomalies related to specific types of tumors. 相似文献
26.
Rolando Gonzlez Jos Clara García‐Moro Silvia Dahinten Miquel Hernndez 《American journal of human biology》2002,14(3):308-320
A complicated history of isolation between Fueguian and Patagonian groups (originated by the appearance of the Straits of Magellan) as much as differences in population structure and life strategies constitute important factors in the clustering pattern of those groups. The aim of this work was to test several hypotheses about population structure and history of Fueguian‐Patagonians to propose a model that incorporates predictions for future studies. R matrix methods and matrix permutation analyses were performed upon a data matrix of craniofacial measurements of 441 skulls divided into nine samples pertaining to six Patagonian and three Fueguian populations. Association of biological distances with three matrices representing several settlement patterns was tested using matrix permutation tests. Results of R matrix study show that the minimum genetic distance obtained confirms separation between Fueguians and Patagonians. Moreover, an analysis of residual variances from the expected regression line confirms admixture between Andean and Pampean populations and Araucanian groups, consistent with ethnohistorical observations. A model representing a long history of isolation between Fueguian and Patagonians, rather than a model emphasizing differences in life‐strategies, presented the best correlation with the biological distance matrix. Because similar results were already obtained in archaeological, molecular, and morphological studies, a model for the settlement of Tierra del Fuego is proposed. It is summarized by four main hypotheses that can be tested independently by different disciplines in the future. Am. J. Hum. Biol. 14:308–320, 2002. © 2002 Wiley‐Liss, Inc. 相似文献
27.
Gianluca Taccagni Clara Sambade Jahn Nesland Maria Rosa Terreni Manuel Sobrinho-Simões 《Virchows Archiv : an international journal of pathology》1993,422(6):491-497
We describe three cases of solitary fibrous tumour (SFT) arising from thyroid stroma. Grossly, the tumours were clearly delimited but only partly encapsulated. The following histomorphological growth patterns were observed: bundles of cells in storiform configuration; non-structured bundles; prevalence of fibrous matrix; highly cellular, non-structured; prevalence of loose, non-structured extracellular substance; cellular proliferation and vascular spaces in a haemangiopericytic configuration and a lipomatous component. Immunohistochemical investigation demonstrated intense, diffuse vimentin positivity and focal, less intense actin positivity in all three cases. At electron microscopy we observed a primitive cell of mesenchymal type, with cytoplasm poor in organelles and rich in filaments; this cell sometimes presented differentiation characteristics. SFT is at present the most correct term for the lesions presented here despite some morphological characteristics which differ from cases reported in the literature. 相似文献
28.
Robert J. Karp Clara Williams Jeanne-Olivia Grant 《Journal of the National Medical Association》1980,72(3):197-200
In a survey of black inner-city school children 10 to 13 years of age, a significant correlation was found for obesity index (weight/height2) and measurements of systolic blood pressure. Significant correlations were found for both blood pressure and obesity index of mothers and daughters. No such relationships were found for mothers and sons. There was an increased availability of sodium-rich foods found for girls as their age increased. This was not found for boys. 相似文献
29.
A membrane cofactor protein transgenic mouse model for the study of discordant xenograft rejection 总被引:1,自引:0,他引:1
Nikos Yannoutsos Jan N. M. IJzermans Clara Harkes Fred Bonthuis Chun-Yan Zhou David White Richard L. M. Marquet & Frank Grosveld 《Genes to cells : devoted to molecular & cellular mechanisms》1996,1(4):409-419
Background: In recent years, interest has been revived in the possibility of transplanting organs into humans from a phylogenetically disparate species such as the pig (xenotransplantation). Such discordant xenografts, however, are subject to hyperacute rejection (HAR) and activation of host complement plays a major role in this rejection. This problem may be solved through the use of transgenic technology by providing the grafted tissue with molecules that down-regulate the action of host complement.
Results: Transgenesis with a yeast artificial chromosome (YAC) was used to produce transgenic mice with the complete genomic gene of the human complement regulator membrane cofactor protein (MCP). Transgenic mice were obtained that exhibit full regulation of MCP as normally observed in humans. Hearts from these mice were shown to be significantly protected from HAR caused by human serum in an in vivo experimental procedure.
Conclusions: We conclude that MCP can protect discordant xenografts from HAR caused by human serum and that transgenic mice can be used effectively as in vivo models for the study of the role of human complement regulatory molecules in xenotransplantation. 相似文献
Results: Transgenesis with a yeast artificial chromosome (YAC) was used to produce transgenic mice with the complete genomic gene of the human complement regulator membrane cofactor protein (MCP). Transgenic mice were obtained that exhibit full regulation of MCP as normally observed in humans. Hearts from these mice were shown to be significantly protected from HAR caused by human serum in an in vivo experimental procedure.
Conclusions: We conclude that MCP can protect discordant xenografts from HAR caused by human serum and that transgenic mice can be used effectively as in vivo models for the study of the role of human complement regulatory molecules in xenotransplantation. 相似文献
30.
Vignozzi L Vannelli GB Morelli A Mancina R Marini M Ferruzzi P Crescioli C Luconi M Donati S Fisher AD Baldi E Filippi S Forti G Maggi M 《Molecular human reproduction》2005,11(2):99-106
Although abnormalities of the male external genitalia (MEG) are a relatively common problem, little is known concerning the molecular mechanisms that finely regulate penile development. We report here the expression of the oxytocin receptor (OTR) gene by real-time RT-PCR in human fetal tissues (11th-12th week of gestation), including the MEG. The developing penis expressed a very high level of OTR mRNA, only a half log(10) unit lower than fetal central nervous system, used as a positive control. The OTR protein is also highly expressed (western, immunohistochemistry and binding studies) and immunolocalized both in the mesenchymal body and in the surrounding blood capillaries, which will later constitute penile trabeculae and sinusoids. Binding studies using [125I]oxytocin antagonist ([125I]OTA) in cultured human fetal penile smooth muscle cells (hfPSMC) revealed the presence of specific OTR with a high capacity and affinity for oxytocin (OT) and for OTA. Increasing concentrations of OT dose-dependently induced intracellular Ca2+ mobilization. Furthermore, OTR mediated an increase in the proliferation and the migration of hfPSMC. In conclusion, we demonstrate that in the developing human MEG, OTR is highly expressed and might be involved in coordinating timely and appropriate proliferation and migration of the penile cells. Thus, OTR might represent an additional target for investigating human fetal MEG organogenesis. 相似文献