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91.
doublecortin is the major gene causing X-linked subcortical laminar heterotopia (SCLH) 总被引:12,自引:0,他引:12
des Portes V; Francis F; Pinard JM; Desguerre I; Moutard ML; Snoeck I; Meiners LC; Capron F; Cusmai R; Ricci S; Motte J; Echenne B; Ponsot G; Dulac O; Chelly J; Beldjord C 《Human molecular genetics》1998,7(7):1063-1070
Subcortical laminar heterotopia (SCLH), or 'double cortex', is a cortical
dysgenesis disorder associated with a defect in neuronal migration.
Clinical manifestations are epilepsy and mental retardation. This disorder,
which mainly affects females, can be inherited in a single pedigree with
lissencephaly, a more severe disease which affects the male individuals.
This clinical entity has been described as X- SCLH/LIS syndrome. Recently
we have demonstrated that the doublecortin gene, which is localized on the
X chromosome, is implicated in this disorder. We have now performed a
systematic mutation analysis of doublecortin in 11 unrelated females with
SCLH (one familial and 10 sporadic cases) and have identified mutations in
10/11 cases. The sequence differences include nonsense, splice site and
missense mutations and these were found throughout the gene. These results
provide strong evidence that loss of function of doublecortin is the major
cause of SCLH. The absence of phenotype-genotype correlations suggests that
X-inactivation patterns of neuronal precursor cells are likely to
contribute to the variable clinical severity of this disorder in females.
相似文献
92.
de Oliveira NM Vaca Sánchez R Rodriguez Fiesta S Lopez Salgado T Rodríguez R Bethencourt JC Blanes Zamora R 《Human reproduction (Oxford, England)》2004,19(2):262-265
BACKGROUND: There are few reports of pregnancy using immotile sperm, and none using a purely mechanical assessment of viability. METHODS: In this pilot study, we retrospectively analysed 66 cycles in 61 patients with determinant male factor, recording rates of fertilization, implantation, normal pregnancy and take-home babies achieved with ICSI. Sperm selection was based on morphologically normal appearance under the inverted microscope. Viability of immotile spermatozoa was assessed by the mechanical touch technique to observe tail flexibility and tail shape recovery. RESULTS: Of 17 ICSI cycles using frozen-thawed testicular sperm, six microinjected with immotile and 11 with motile sperm, we achieved fertilization rates of 65.7 and 74.3%, respectively, and five pregnancies (two and three, respectively). Of 49 ICSI cycles using fresh testicular sperm, 10 microinjected with immotile and 39 with motile sperm, we achieved fertilization rates of 73.4 and 64.4%, respectively, and 12 pregnancies (three and nine, respectively). CONCLUSIONS: Immotile (fresh and frozen-thawed) testicular sperm of normal morphological appearance can be used to achieve clinical pregnancy with ICSI. Our results strongly suggest that immotile sperm viability can be assessed by the mechanical touch technique. 相似文献
93.
94.
Clonal Distribution of Methicillin-Resistant Staphylococcus aureus in Poland 总被引:3,自引:0,他引:3 下载免费PDF全文
T. Leski D. Oliveira K. Trzcinski I. Santos Sanches M. Aires de Sousa W. Hryniewicz H. de Lencastre 《Journal of clinical microbiology》1998,36(12):3532-3539
We report on a study of 158 methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates obtained from 1990 to 1996 in 18 different hospitals in Poland. All isolates were recovered from infection and carriage sites of patients, carriage sites of health care personnel, and hospital environment samples. Fifty-seven MRSA strains described here were studied previously and these were divided into two different clusters according to the degree of heterogeneity of methicillin resistance expression. The aim of this study was to extend the correlation between the two clusters and identify the clonal identities among all isolates by a combination of different methodologies: (i) analysis of mecA polymorphs and Tn554 insertion patterns and (ii) determination of pulsed-field gel electrophoresis patterns of chromosomal SmaI digests. Ninety-seven of 158 strains showed a heterogeneous expression of resistance to methicillin. Among these, 75 (77.3%) were ClaI-mecA type I, ClaI-Tn554 type NH (NH, no homology with transposon Tn554), and pulsed-field gel electrophoresis (PFGE) pattern A (I::NH::A); 10 isolates were III::B::M (10.3%); and the remaining clones included a few or single isolates. The isolates with homogeneous expression of resistance to methicillin (n = 61) were predominantly ClaI-mecA type III (49 of 61 [80.3%]) but had great variability in their ClaI-Tn554 and PFGE patterns. This study confirmed the existence of two main clusters of MRSA in Poland. 相似文献
95.
96.
Interchromosomal duplications of the adrenoleukodystrophy locus: a phenomenon of pericentromeric plasticity 总被引:13,自引:5,他引:13
Eichler EE; Budarf ML; Rocchi M; Deaven LL; Doggett NA; Baldini A; Nelson DL; Mohrenweiser HW 《Human molecular genetics》1997,6(7):991-1002
A 9.7 kb segment encompassing exons 7-10 of the adrenoleukodystrophy (ALD)
locus of the X chromosome has duplicated to specific locations near the
pericentromeric regions of human chromosomes 2p11,10p11, 16p11 and 22q11.
Comparative sequence analysis reveals 92-96% nucleotide identity,
indicating that the autosomal ALD paralogs arose relatively recently during
the course of higher primate evolution (5-10 million years ago). Analysis
of sequences flanking the duplication region identifies the presence of an
unusual GCTTTTTGC repeat which may be a sequence-specific integration site
for the process of pericentromeric- directed transposition. The breakpoint
sequence and phylogenetic analysis predict a two-step transposition model,
in which a duplication from Xq28 to pericentromeric 2p11 occurred once,
followed by a rapid distribution of a larger duplicon cassette among the
pericentromeric regions. In addition to facilitating more effective
mutation detection among ALD patients, these findings provide further
insight into the molecular basis underlying a pericentromeric-directed
mechanism for non- homologous interchromosomal exchange.
相似文献
97.
Human mini-chromosomes in mouse embryonal stem cells 总被引:3,自引:2,他引:3
We have introduced human mini-chromosomes of 4 Mb and approximately 15 Mb
in size into mouse embryonal stem cells. Although these human mini-
chromosomes are stable in hamster and chicken cells, they re-arrange or
segregate aberrantly in the embryonal stem cells and are rapidly lost in
the absence of selection. However, one of the mini-chromosomes re-
arranged, acquired mouse centromeric sequences and was then stably
maintained for at least 60 population doublings in culture. This mini-
chromosome, which is 4 Mb in size, is a candidate for a mouse germ line
chromosome vector.
相似文献
98.
Induction of an adaptive response to quercetin, mitomycin C and hydrogen peroxide by low doses of quercetin in V79 Chinese hamster cells 总被引:1,自引:3,他引:1
The adaptive response is a phenomenon by which cells exposedto low, non-cytotoxic doses of a genotoxicant become significantlyresistant to a subsequent higher dose of the same or anothergenotoxic agent. Induction of the adaptive response has beenmainly studied using ionizing radiation and alkylating agentsas genotoxic agents. However, other mutagenic agents may warrantfurther study, since the adaptive response as a whole may bean important general biological mechanism to maintain geneticintegrity and thus could prevent carcinogenic initiation ofcells. The exposure to mutagenic agents present, or formed,in the diet is considered an important factor in the etiologyof human tumors and a considerable number of these agents havenot yet been identified or characterized. Flavonoids are a largegroup of polyphenolic quinoids found in a wide variety of ediblefruits and vegetables and a few, such as quercetin, presentgenotoxic activity in vitro. The mechanisms of mutagenicityof quercetin involve the production of oxygen radicals throughan autoxidation process dependent on pH value and the presenceof oxygen. Although there are few doubts regarding the mutagenicityof quercetin invitro, carcinogenicity of this flavonoid is stillcontroversial. In view of these conflicting results and theradiomimetic nature of the mutagenicity of flavonoids, we addressedthe question of cell exposure to quercetin at the low levelspresent in the diet leading to adaptation to further exposureto mutagens or carcinogens. The work reported here concernsinduction of an adaptive response by low doses of quercetinto challenging doses of quercetin and other compounds, namelyhydrogen peroxide and mitomycin C, using induction of chromosomalaberrations in V79 cells as the end point.
4To whom correspondence should be addressed: Tel: +351 1 3610290; Fax: +351 1 3622018; Email: jose.rueff{at}gene.unl.mailpac.pt 相似文献
99.
The intravenous administration of nephrotoxic antibody serum to rats produced a rapid and pronounced reduction in the serum complement level; this was observed before lung lesions became apparent.
A total suppression of the acute immune lung change was observed in animals depleted of complement by treatment with heat-aggregated human γ-globulin or zymosan.
Albeit the experimental evidence presented is of indirect nature, it suggests that the complement system is involved in the mediation of the acute pulmonary injury following injection of nephrotoxic antibody serum.
相似文献100.