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31.
A microdeletion of less than 250 kb, including the proximal part of the FMR-1 gene and the fragile-X site, in a male with the clinical phenotype of fragile-X syndrome
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Doris Whrle Dieter Kotzot Mark C. Hirst Antonella Manca Bernhard Korn Angela Schmidt Gotthold Barbi Hans-Dieter Rott Annemarie Poustka Kay E. Davies Peter Steinbach 《American journal of human genetics》1992,51(2):299-306
A gene designated "FMR-1" has been isolated at the fragile-X locus. One exon of this gene is carried on a 5.1-kb EcoRI fragment that exhibits length variation in fragile-X patients because of amplification of or insertion into a CGG-repeat sequence. This repeat probably represents the fragile site. The EcoRI fragment also includes an HTF island that is hypermethylated in fragile-X patients showing absence of FMR-1 mRNA. In this paper, we present further evidence that the FMR-1 gene is involved in the clinical manifestation of the fragile-X syndrome and also in the expression of the cellular phenotype. A deletion including the HTF island and exons of the FMR-1 gene was detected in a fragile X-negative mentally retarded male who presented the clinical phenotype of the fragile-X syndrome. The deletion involves less than 250 kb of genomic DNA, including DXS548 and at least five exons of the FMR-1 gene. These data support the hypothesis that loss of function of the FMR-1 gene leads to the clinical phenotype of the fragile-X syndrome. In the fragile-X syndrome, there are pathogenetic mechanisms other than amplification of the CGG repeat that do have the same phenotypic consequences. 相似文献
32.
Selenium,zinc, and thyroid hormones in healthy subjects 总被引:3,自引:0,他引:3
Oliviero Olivieri Domenico Girelli Anna Maria Stanzial Luigi Rossi Antonella Bassi Roberto Corrocher 《Biological trace element research》1996,51(1):31-41
Iodothyronine 5′ deiodinase, which is mainly responsible for peripheral T3 production, has recently been demonstrated to be a selenium (Se)-containing enzyme. The structure of nuclear thyroid hormone
receptors contains Zinc (Zn) ions, crucial for the functional properties of the protein. In the elderly, reduced peripheral
conversion of T4 to T3 with a lower T3/T4 ratio and overt hypothyroidism are frequently observed. We measured serum Se and RBC GSH-Px (as indices of Se status), circulating
and RBC Zinc (as indices of Zn status), thyroid hormones and TSH in 109 healthy euthyroid subjects (52 women, 57 men), carefully
selected to avoid abnormally low thyroid hormone levels induced by acute or chronic diseases or calorie restriction. The subjects
were subdivided into three age groups. To avoid under- or malnutrition conditions, dietary records were obtained for a sample
of 24 subjects, randomly selected and representative of the whole population for age and sex. Low T3/T4 ratios and reduced Se and RBC GSH-Px activity were observed only in the older group. A highly significant linear correlation
between the T3/T4 ratio and indices of Se status was observed in the older group of subjects (r=0.54;p<0.002, for Se;r=0.50;p<0.002, for RBC GSH-Px). Indices of Zn status did not correlate with thyroid hormones, but RBC Zn was decreased in older as
compared with younger subjects. We concluded that reduced peripheral T4 conversion is related to impaired Se status in the elderly. 相似文献
33.
34.
The presence of species and their cover values together with soil and topographic characteristics were recorded at 40 sites along an altitudinal gradient of the Puna Belt at Pozuelos, in the High Andes in northwest Argentina. Classification and ordination of plant assemblages showed that soil and topography were the best predictors of the variation in species distribution. The different plant assemblages which occur along the topographic gradient follow the geographic variation in rainfall in this Andean region. Perennial bushes and grasses colonize the plains and slopes with fine textured soils which retain their water content. In contrast, deciduous bushes and cactuses grow on steep, rocky, dry slopes. Open woods also occur on east-facing steep, rocky slopes which are sheltered from winds. 相似文献
35.
Antagonists were used to investigate the role of the excitatory amino acid,l-glutamate, in the swim motor program ofHirudo medicinalis. In previous experiments, focal application ofl-glutamate or its non-NMDA agonists onto either the segmental swim-gating interneuron (cell 204) or the serotonergic Retzius cell resulted in prolonged excitation of the two cells and often in fictive swimming. Since brief stimulation of the subesophageal trigger interneuron (cell Tr1) evoked a similar response, we investigated the role of glutamate at these synapses. Kynurenic acid and two non-NMDA antagonists, 6,7-dinitroquinoxaline-2,3-dione (DNQX) and Joro spider toxin, effectively suppressed (1) the sustained activation of cell 204 and the Retzius cell following cell Tr1 stimulation and (2) the monosynaptic connection from cell Tr1 to cell 204 and the Retzius cell, but did not block spontaneous or DP nerve-activated swimming. Other glutamate blockers, including -d-glutamylaminomethyl sulfonic acid,l(+)-2-amino-3-phosphonoproprionic acid and 2-amino-5-phosphonopentanoic acid, were ineffective. DNQX also blocked both indirect excitation of cell 204 and direct depolarization of cell Tr1 in response to mechanosensory P cell stimulation. Our findings show the involvement of non-NMDA receptors in activating the swim motor program at two levels: (1) P cell input to cell Tr1 and (2) cell Tr1 input to cell 204, and reveal an essential role for glutamate in swim initiation via the cell Tr1 pathway. 相似文献
36.
Ana M. Celentano Gabriela Gorelik María E. Solana Leonor Sterin-Borda Enri Borda Stella M. Gonzlez Cappa 《Prostaglandins & other lipid mediators》1995,49(3)
PGE2 involvement in experimental Trypanosoma cruzi infection depends on the lethal capacity of the parasite subpopulation used. Mice acutely infected with non-lethal K98 displayed an enhancement in PGE2 serum levels during the acute period, while those infected with lethal T. cruzi subpopulations (RA or K98-2) showed levels not different from normal mice. The enhancement detected in K98 group could be related both to an increased number of CD8+ T cell number and to enhanced PGE2 release per cell by CD8+; values of PGE2 release by adherent cells were not altered in this group. Treatment with cyclooxygenase inhibitors enhanced mortality rates of mice infected with K98, and administration of 16,16-dimethyl PGE2 (dPGE) reversed this effect. However, mice infected with RA did not reduce their mortality rates by administration of diverse doses of dPGE. These findings suggest that PGE2 could play a role in resistance in mice infected with K98. 相似文献
37.
38.
Nicola Maggiano Franco Citterio Antonella Evangelista Ubaldo Pozzetto Marco Castagneto Arnaldo Capelli 《The Histochemical journal》1994,26(7):553-562
Summary The targets of preformed natural antibodies need to be identified whenever the use of pig organs is considered for human transplantation. In this study we used extracorporeal perfusion of pig organs with human blood, immunocytological techniques and immuno-electron microscopy to identify the targets and the nature of human preformed natural antibodies against pig antigens. The antibodies were found to be mainly of the IgG and IgM type and directed not only against endothelial cells, but also against mesenchymal and epithelial structures. To reproduce an in vivo situation, a Bio-pump was used to xenoperfuse pig kidneys and livers with human fresh oxygenated blood at 37°C, drawn from polycythaemic patients. Biopsies showed a deposition of human IgG and IgM on tubuli and glomeruli of pig kidneys and on endothelial cells of pig livers. Preperfusion of pig liver with human blood for 45 minutes before perfusion of kidneys significantly reduced the deposition of the natural antibodies. 相似文献
39.
A systematic study of the Vernonia leopoldi complex was undertaken with the objective of determining the taxonomic status of the species involved within this group. TWo species, i.e. Vernonia leopoldi and V. bipontini have been recognized as distinct based on evidence from morphological studies accompanied by field observations and anatomical studies (particularly trichomes and petioles). Both species have 2n = 36 (first reports). Three new varieties have been recognized within V. bipontini , namely var. bipontini , var. gonderensis and var. caccaensis . A lectotype is selected for V. leopoldi . 相似文献
40.
Lucia Potenza Antonella Amicucci Ismaela Rossi Francesco Palma Roberta De Bellis Paola Cardoni Vilberto Stocchi 《Biotechnology Techniques》1994,8(2):93-98
Summary Different species of truffle were studied in order to identify species-specific markers. The isolation of two Tuber magnatum Pico markers is reported. One of these could be used as a probe in dot blot hybridization, allowing the development of a rapid test able to identify Tuber magnatum species. 相似文献