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排序方式: 共有2413条查询结果,搜索用时 375 毫秒
31.
32.
Berge-Lefranc JL; Jay P; Massacrier A; Cau P; Mattei MG; Bauer S; Marsollier C; Berta P; Fontes M 《Human molecular genetics》1996,5(10):1637-1641
While constructing a cDNA library of human embryos, we have isolated a
clone homologous to jumonji, a mouse gene required for neural tube
formation. We have determined the complete coding sequence of the human
homologue (JMJ) and deduced the amino acid sequence of the putative
protein. We show here that human and mouse jumonji putative proteins are
homologous and present 90% identity. During human embryogenesis, JMJ mRNAs
are predominantly expressed in neurons and particularly in dorsal root
ganglion cells. They are also expressed in neurons of human adult cerebral
cortex. In view of these observations, we propose JMJ as a candidate gene
for developmental defects of the central nervous system in the human. The
human JMJ gene maps at position 6p24-6p23.
相似文献
33.
Rats having either sham operations or one-stage bilateral lesions of the two somatosensory areas of the cortex were tested for acquisition of five tactile discriminations after postoperative recovery intervals of 14, 35, 180, 365 or 730 days. The group with lesions performed worse than its time-matched control group in every instance, and there was no evidence for recovery of function with the longer postoperative recovery periods. These results suggest that time per se is not a significant determinant of restitution after somatosensory cortical ablations. 相似文献
34.
How to use Chlamydia antibody testing in subfertility patients 总被引:1,自引:9,他引:1
Screening for tubal factor subfertility by means of Chlamydia antibody
testing (CAT) was introduced into the initial work-up of subfertile couples
several years ago. The results reported, however, are heterogeneous, and no
uniformity exists in cut-off levels of titres, or in definitions of tubal
factor subfertility. We performed a prospective cohort study to evaluate
the implications of varying the definitions of tubal pathology and of
modifying the cut-off levels on the clinical impact of CAT in predicting
tubal factor subfertility. In 227 consecutive patients who attended our
fertility clinic, the Chlamydia IgG antibody titre was determined and
related to tuboperitoneal abnormalities at laparoscopy as a reference
standard. According to received operating characteristic (ROC) curve
analysis, a titre of 16 is the optimum cut-off level. Increasing the
cut-off level improves specificity and positive likelihood ratio (LR+), at
the expense of sensitivity and negative LR (LR-). Changing the definition
of tubal factor subfertility from unspecified tuboperitoneal abnormalities
into extensive adhesions and/or bilateral distal tubal occlusion improves
LR+, LR- and kappa significantly. We conclude that CAT is more accurate in
predicting severe distal tubal pathology than unspecified tuboperitoneal
abnormalities. Although from a statistical point of view a titre of 16 is
the optimum cut-off level, from a clinical point of view 32 or 64 may be
preferable, depending on the aim of screening and the inception cohort.
相似文献
35.
Pal L; Leykin L; Schifren JL; Isaacson KB; Chang YC; Nikruil N; Chen Z; Toth TL 《Human reproduction (Oxford, England)》1998,13(7):1837-1840
A case series of eight cycles of in-vitro fertilization (IVF) in five women
diagnosed with malignant disorders is presented. These patients chose to
defer definitive treatment for a chance for preservation of potential
fertility. The response of these patients to ovarian stimulation, and the
outcome, was compared with 17 IVF cycles in 12 age- matched patients with
isolated tubal infertility. An apparent adverse influence of malignant
disease on the quality and behaviour of oocytes was observed. Despite a
comparable total number of oocytes per cycle in the two groups, a
significantly reduced percentage of mature oocytes was retrieved per cycle
from patients with malignant diseases. The oocytes from patients with
malignant disorders were of a poorer quality and exhibited a significantly
impaired fertilization rate compared to the controls. We propose that
neoplastic processes, irrespective of the site or cell of origin, may have
a detrimental impact on the biology of oocytes, an effect akin to that seen
on spermatozoa in men with certain malignancies.
相似文献
36.
37.
Distribution of mutations in the PEX gene in families with X-linked hypophosphataemic rickets (HYP) 总被引:8,自引:0,他引:8
Rowe PS; Oudet CL; Francis F; Sinding C; Pannetier S; Econs MJ; Strom TM; Meitinger T; Garabedian M; David A; Macher MA; Questiaux E; Popowska E; Pronicka E; Read AP; Mokrzycki A; Glorieux FH; Drezner MK; Hanauer A; Lehrach H; Goulding JN; O'Riordan JL 《Human molecular genetics》1997,6(4):539-549
Mutations in the PEX gene at Xp22.1 (phosphate-regulating gene with
homologies to endopeptidases, on the X-chromosome), are responsible for
X-linked hypophosphataemic rickets (HYP). Homology of PEX to the M13 family
of Zn2+ metallopeptidases which include neprilysin (NEP) as prototype, has
raised important questions regarding PEX function at the molecular level.
The aim of this study was to analyse 99 HYP families for PEX gene
mutations, and to correlate predicted changes in the protein structure with
Zn2+ metallopeptidase gene function. Primers flanking 22 characterised
exons were used to amplify DNA by PCR, and SSCP was then used to screen for
mutations. Deletions, insertions, nonsense mutations, stop codons and
splice mutations occurred in 83% of families screened for in all 22 exons,
and 51% of a separate set of families screened in 17 PEX gene exons.
Missense mutations in four regions of the gene were informative regarding
function, with one mutation in the Zn2+-binding site predicted to alter
substrate enzyme interaction and catalysis. Computer analysis of the
remaining mutations predicted changes in secondary structure,
N-glycosylation, protein phosphorylation and catalytic site molecular
structure. The wide range of mutations that align with regions required for
protease activity in NEP suggests that PEX also functions as a protease,
and may act by processing factor(s) involved in bone mineral metabolism.
相似文献
38.
Zusammenfassung Die im Verlaufe antirabischer Vaccinationen gelegentlich auftretenden paralytischen Komplikationen sind nicht virusbedingt, sondern die Folge einer Antigen-Antikörperreaktion nach Sensibilisierung mit dem organspezifischen Hirnantigen, das in den nicht ätherisierten Tollwutvaccinen enthalten ist. Diesbezüglich von einer Impfwut zu sprechen, erscheint nicht gerechtfertigt. Vielmehr sollte dieser Terminus für die postvaccinalen Komplikationen reserviert bleiben, bei denen der Ausbruch der Erkrankung in direktem Kausalzusammenhang zu dem in einer Vaccine enthaltenen lebenden Virus fixe steht. 相似文献
39.
Alternative splicing of exon 14 determines nuclear or cytoplasmic localisation of fmr1 protein isoforms 总被引:6,自引:9,他引:6
Impaired expression of the FMR1 gene is responsible for the fragile X
mental retardation syndrome. The FMR1 gene encodes a cytoplasmic protein
with RNA-binding properties. Its complex alternative splicing leads to
several isoforms, whose abundance and specific functions in the cell are
not known. We have cloned in expression vectors, cDNAs corresponding to
several isoforms. Western blot comparison of the pattern of endogenous FMR1
proteins with these transfected isoforms allowed the tentative
identification of the major endogenous isoform as ISO 7 and of a minor band
as an isoform lacking exon 14 sequences (ISO 6 or ISO 12), while some other
isoforms (ISO 4, ISO 5) were not expressed at detectable levels.
Surprisingly, in immunofluorescence studies, the transfected splice
variants that exclude exon 14 sequences (and have alternate C-terminal
regions) were shown to be nuclear. Such differential localisation was
however not seen in subcellular fractionation studies. Analysis of various
deletion mutants suggests the presence of a cytoplasmic retention domain
encoded in exon 14 and of a nuclear association domain encoded within the
first eight exons that appear however to lack a typical nuclear
localisation signal.
相似文献
40.
Zusammenfassung Verglichen mit phänotypisch normalen Kontrolltieren fanden sich bei NMRI-Mäusen mit kongenitaler Thymusaplasie nur wenige Peyersche Plaques, die zudem nur aus diffusen Lymphocytenansammlungen bestanden. Auch die Milzfollikel waren erheblich verkleinert, wobei die periarteriolären Follikelbereiche gelegentlich zellärmer erschienen. Das wei\e Blutbild der thymuslosen Tiere war durch eine mä\ige Lymphopenie charakterisiert. Obwohl die Milzen der Mäuse mit kongenitaler Thymusaplasie keine Verringerung der Zahlen an präexistenten 19S-Hämolysin-bildenden Zellen aufweisen, waren nach Erstimmunisierung mit 4·108 Schaferythrocyten nur minimale Zahlen an 19S-Produzenten und 7 S-Produzenten nachweisbar. Die sekundäre antigene Stimulierung mit 4·108 Schaferythrocyten führte zu keiner nennenswerten Gedächtnisreaktion, was anzeigt, da\ die Bildung von Gedächtniszellen ein thymusabhängiger Proze\ ist. Die alleinige intraperitoneale Injektion abgetöteter Zellen von B. pertussis führte zu Hypersplenie, Leukozytose und Vermehrung der präexistenten Zahlen an 19S-Hämolysin-bildenden Zellen. Im Gegensatz zu Normaltieren, wo die Leukocytose durch eine Vermehrung von Granulocyten und Lymphocyten charakterisiert ist, fehlte bei den thymuslosen Tieren die Lymphocytenvermehrung. Der Zunahme der Blutgranulocyten entsprach eine verstärkte Granulopoese in Leber und Milz. Bei Normaltieren fand sich nach Erstimmunisierung durch simultane Applikation von 4·108 Schaferythrocyten und 3·109 abgetöteten Zellen vonB. pertussis eine verstärkte und verlängerte Produktion von 19S- und besonders 7S-Hämolysin-bildenden Zellen, verbunden mit einer verstärkten Präparation des lymphoretikulären Gewebes für die anamnestische Reaktion. Bei den Mäusen mit kongenitaler Thymusaplasie beschränkte sich der Adjuvanseffekt allem auf die Frühphase der immunologischen Primärreaktion, was seinen Ausdruck in einer deutlichen Vermehrung der 19S-Produzenten und einer nur geringgradigen Vermehrung der 7S-Produzenten fand.
Diese Arbeit wurde durch die Deutsche Forschungsgemeinschaft gefördert. 相似文献
Influence ofBordetella pertussis on the lymphatic tissue of miceVIII. The influence ofBordetella pertussis on the primary and secondary immune potential of thymusless (nude) mice
As compared to phenotypically normal controls, in the intestine of NMRI mice with congenital aplasia of the thymus (nude) only small numbers of Peyer's patches could be detected, which consisted of relatively diffuse accumulations of lymphocytes. The splenic follicles were likewise considerably reduced in size, whereby the thymus-dependent areas occasionally appeared to be deficient in lymphocytes. Furthermore, the thymusless mice were found to have blood lymphopenia. Although the spleens of nude mice contained rather enhanced numbers of pre-existing 19S hemolysin forming cells, only small numbers of 19S producers and very poor numbers of 7S hemolysin-forming spleen cells were demonstrable after the primary immunization with 4·108 sheep erythrocytes. Secondary antigenic stimulation with an equal dose of the erythrocyte antigen did not result in a noteworthy secondary immune response. This evidently indicates that the production of memory cells is a thymus-dependent process. A single intraperitoneal injection of 3·109 pertussis organisms led to splenomegaly, blood leukocytosis and augmentation of the pre-existing 19S hemolysin-forming spleen cells. Whilst in normal controls the blood leukocytosis was found to be due to an increase in both lymphocytes and granulocytes, in nude mice the leukocytosis was solely caused by the increase in granulocytes, this being associated with increased granulopoiesis in spleen and liver. The primary immunization of normal controls with 4·108 sheep erythrocytes and 3·109 pertussis organisms led to an increased and prolonged development of both 19S and 7S hemolysin-producing spleen cells. Furthermore, the bacterial adjuvant increased the process of priming for the secondary immune response. Unlike to this, in mice with congenital aplasia of the thymus adjuvancy of pertussis organisms was restricted to the early phase of the primary immune response, as is documented by the distinct augmentation of 19S producers and a poor increase in the numbers of 7S hemolysin-forming spleen cells.
Diese Arbeit wurde durch die Deutsche Forschungsgemeinschaft gefördert. 相似文献