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排序方式: 共有56条查询结果,搜索用时 31 毫秒
41.
Freya KR Swinnen Paul J Coucke Anne M De Paepe Sofie Symoens Fransiska Malfait Filomena V Gentile Luca Sangiorgi Patrizia D’Eufemia Mauro Celli Ton JTM Garretsen Cor WRJ Cremers Ingeborg JM Dhooge Els MR De Leenheer 《Orphanet journal of rare diseases》2011,6(1):1-8
Background
Neurofibromatosis 1 (NF1), a common autosomal dominant disorder, was shown in one study to be associated with a 15-year decrease in life expectancy. However, data on mortality in NF1 are limited. Our aim was to evaluate mortality in a large retrospective cohort of NF1 patients seen in France between 1980 and 2006.Methods
Consecutive NF1 patients referred to the National French Referral Center for Neurofibromatoses were included. The standardized mortality ratio (SMR) with its 95% confidence interval (CI) was calculated as the ratio of observed over expected numbers of deaths. We studied factors associated with death and causes of death.Results
Between 1980 and 2006, 1895 NF1 patients were seen. Median follow-up was 6.8 years (range, 0.4-20.6). Vital status was available for 1226 (65%) patients, of whom 1159 (94.5%) survived and 67 (5.5%) died. Overall mortality was significantly increased in the NF1 cohort (SMR, 2.02; CI, 1.6-2.6; P < 10-4). The excess mortality occurred among patients aged 10 to 20 years (SMR, 5.2; CI, 2.6-9.3; P < 10-4) and 20 to 40 years (SMR, 4.1; 2.8-5.8; P < 10-4). Significant excess mortality was found in both males and females. In the 10-20 year age group, females had a significant increase in mortality compared to males (SMR, 12.6; CI, 5.7-23.9; and SMR, 1.8; CI, 0.2-6.4; respectively). The cause of death was available for 58 (86.6%) patients; malignant nerve sheath tumor was the main cause of death (60%).Conclusions
We found significantly increased SMRs indicating excess mortality in NF1 patients compared to the general population. The definitive diagnosis of NF1 in all patients is a strength of our study, and the high rate of death related to malignant transformation is consistent with previous work. The retrospective design and hospital-based recruitment are limitations of our study. Mortality was significantly increased in NF1 patients aged 10 to 40 years and tended to be higher in females than in males. 相似文献42.
ABSTRACT: Co-evolving positions within protein sequences have been used as spatial constraints to develop a computational approach for modeling membrane protein structures. 相似文献
43.
The inhibitory effect of 23N-alkyl-4-piperidylesters (alkyl = ethyl-butyl) (APEA) and 8N-ethyl-2-pyrrolidinylmethylesters (EPMEA) of 2- and 3-substituted alkoxyphenylcarbamic acids (alkoxy = butoxy-heptyloxy-) on photosynthetic Hill reaction activity of spinach chloroplasts and on chlorophyll (Chl) synthesis in green algaeChlorella vulgaris was investigated. Inhibitory activities of these compounds were strongly connected with the lipophilicity of the whole molecule. A lower inhibitory activity of 2-alkoxy-substituted derivatives in relation to the corresponding 3-substituted ones was confirmed. Electron spin resonance (ESR) spectra of spinach chloroplasts demonstrated that the studied compounds affected the structure of photosystem (PS) 2 with the release of Mn2+ ions into interior of thylakoid membranes. 相似文献
44.
Facile labeling of oligosaccharides (acidic and neutral) in a nonselective
manner was achieved with highly fluorescent anthranilic acid (AA,
2-aminobenzoic acid) (more than twice the intensity of 2- aminobenzamide,
AB) for specific detection at very high sensitivity. Quantitative labeling
in acetate-borate buffered methanol (approximately pH 5.0) at 80 degreesC
for 60 min resulted in negligible or no desialylation of the
oligosaccharides. A high resolution high performance liquid chromatographic
method was developed for quantitative oligosaccharide mapping on a
polymeric-NH2bonded (Astec) column operating under normal phase and anion
exchange (NP-HPAEC) conditions. For isolation of oligosaccharides from the
map by simple evaporation, the chromatographic conditions developed use
volatile acetic acid-triethylamine buffer (approximately pH 4.0) systems.
The mapping and characterization technology was developed using well
characterized standard glycoproteins. The fluorescent oligosaccharide maps
were similar to the maps obtained by the high pH anion-exchange
chromatography with pulsed amperometric detection (HPAEC-PAD), except that
the fluorescent maps contained more defined peaks. In the map, the
oligosaccharides separated into groups based on charge, size, linkage, and
overall structure in a manner similar to HPAEC-PAD with contribution of
-COOH function from the label, anthranilic acid. However, selectivity of
the column for sialic acid linkages was different. A second dimension
normal phase HPLC (NP-HPLC) method was developed on an amide column (TSK
Gel amide-80) for separation of the AA labeled neutral complex type and
isomeric structures of high mannose type oligosaccharides. The
oligosaccharides labeled with AA are compatible with biochemical and
biophysical techniques, and use of matrix assisted laser desorption mass
spectrometry for rapid determination of oligosaccharide mass map of
glycoproteins is demonstrated. High resolution of NP-HPAEC and NP-HPLC
methods combined with mass spectrometry (MALDI-TOF) can provide an
effective technology for analyzing a wide repertoire of oligosaccharide
structures and for determining the action of both transferases and
glycosidases.
相似文献
45.
MOTIVATION: Molecular biology databases hold a large number of empirical
facts about many different aspects of biological entities. That data is
static in the sense that one cannot ask a database 'What effect has protein
A on gene B?' or 'Do gene A and gene B interact, and if so, how?'. Those
questions require an explicit model of the target organism. Traditionally,
biochemical systems are modelled using kinetics and differential equations
in a quantitative simulator. For many biological processes however,
detailed quantitative information is not available, only qualitative or
fuzzy statements about the nature of interactions. RESULTS: We designed and
implemented a qualitative simulation model of lambda phage growth control
in Escherichia coli based on the existing simulation environment QSim.
Qualitative reasoning can serve as the basis for automatic transformation
of contents of genomic databases into interactive modelling systems that
can reason about the relations and interactions of biological entities.
相似文献
46.
A fluorogenic substrate of neuraminidase, 4-methylumbelliferone N-acetylneuraminic acid ketoside (MUN), was synthesized. Km values were obtained for Clostridium perfringens neuraminidase and strains of A- and B-type influenza neuraminidase from chicken red blood cell influenza virus eluates. 相似文献
47.
LARA MODOLO ROBERT D. MARTIN CAREL P. VAN SCHAIK MARIA A. VAN NOORDWIJK MICHAEL KRÜTZEN 《Molecular ecology》2008,17(18):4027-4038
Barbary macaques (Macaca sylvanus), now restricted in the wild to a few isolated forested areas of Morocco and Algeria, are present in a free‐ranging colony on Gibraltar. For many decades, the Gibraltar colony was exposed to multiple bottlenecks due to highly nonrandom removal of animals, followed by repeated introductions of animals from North Africa. Moreover, because of complete isolation, Gibraltar's several social groups of macaques provide an ideal system to study the genetic consequences of dispersal in cercopithecines in situ. Predictions of genetic consequences due to male‐biased dispersal in cercopithecines will be different for autosomal and maternally inherited genetic markers, such as the control region of the mitochondrial DNA. We used a panel of 14 highly polymorphic microsatellite loci and part of the hypervariable region I of the mitochondrial control region to estimate genetic structure between five social groups in Gibraltar. Surprisingly, for autosomal markers, both classical summary statistics and an individual‐based method using a Bayesian framework detected significant genetic structure between social groups in Gibraltar, despite much closer proximity than wild Algerian and Moroccan populations. Mitochondrial data support this finding, as a very substantial portion of the total genetic variation (70.2%) was found between social groups. Using two Bayesian approaches, we likewise identified not only a small number of male first‐generation immigrants (albeit less than expected for cercopithecines) but also unexpectedly a few females. We hypothesize that the culling of males that are more likely to disperse might slow down genetic homogenization among neighbouring groups, but may also and more perversely produce selection on certain behavioural traits. This may have important repercussions for conservation, as it could lead to evolutionary changes that are not due to inbreeding or genetic drift. 相似文献
48.
Mohamed Ashry KyungBon Lee Joseph K. Folger Sandeep K. Rajput George W. Smith 《Reproductive biology》2018,18(3):267-273
Using sex-sorted semen to produce offspring of desired sex is associated with reduced developmental competence in vitro and lower fertility rates in vivo. The objectives of the present study were to investigate the effects of exogenous follistatin supplementation on the developmental competence of bovine embryos produced with sex-sorted semen and possible link between TGF-β regulated pathways and embryotrophic actions of follistatin. Effects of follistatin on expression of cell lineage markers (CDX2 and Nanog) and downstream targets of SMAD signaling (CTGF, ID1, ID2 and ID3) and AKT phosphorylation were investigated. Follistatin was supplemented during the initial 72?h of embryo culture. Exogenous follistatin restored the in vitro developmental competence of embryos produced with sex-sorted semen to the levels of control embryos produced with unsorted semen, and comparable results were obtained using sorted semen from three different bulls. The mRNA abundance for SMAD signaling downstream target genes, CTGF (SMAD 2/3 pathway) and ID2 (SMAD 1/5 pathway), was lower in blastocysts produced using sex-sorted versus unsorted semen, but mRNA levels for CDX2, NANOG, ID1 and ID3 were similar in both groups. Follistatin supplementation restored CTGF and ID2 mRNA in blastocysts produced using sex-sorted semen to levels of control embryos. Moreover, levels of phosphorylated (p)AKT (Ser-473 and Thr-308) were similar in embryos derived from sex-sorted and unsorted semen, but follistatin treatment increased pAKT levels in both groups. Taken together, results demonstrated that follistatin improves in vitro development of embryos produced with sex-sorted semen and such effects are associated with enhanced indices of SMAD signaling. 相似文献
49.
Vidar Beisvag Frode KR Jünge Hallgeir Bergum Lars Jølsum Stian Lydersen Clara-Cecilie Günther Heri Ramampiaro Mette Langaas Arne K Sandvik Astrid Lægreid 《BMC bioinformatics》2006,7(1):470-13
Background
Modern biology has shifted from "one gene" approaches to methods for genomic-scale analysis like microarray technology, which allow simultaneous measurement of thousands of genes. This has created a need for tools facilitating interpretation of biological data in "batch" mode. However, such tools often leave the investigator with large volumes of apparently unorganized information. To meet this interpretation challenge, gene-set, or cluster testing has become a popular analytical tool. Many gene-set testing methods and software packages are now available, most of which use a variety of statistical tests to assess the genes in a set for biological information. However, the field is still evolving, and there is a great need for "integrated" solutions. 相似文献50.
Bovine lymphocytotoxicity tests with 20 unabsorbed bovine blood group sera revealed extensive reactivity which in the majority of cases had no indication of blood group relationship. Six of these sera were absorbed with selected lymphocytes to produce eleven antisera of reduced specificity. Again, most of the sera had reaction patterns which could not be related to the hemolytic patterns of any known blood group antibodies. However, five comparisons involving unabsorbed antisera and two comparisons involving absorbed antisera provided statistical evidence of similarities between their lymphocytotoxic reaction patterns and the hemolytic reaction patterns of certain blood group antibodies. Several of the sera appeared to contain related cytotoxic specificities, and three such absorbed sera may have contained an anti-J specificity. All six examined monospecific isoimmune blood group antisera contained lymphocytic reactivities not related to their hemolytic specificites. Two normal sera containing naturally occurring anti-J had no cytotoxic activity. Anti-semen sera likewise were devoid of lymphocytotoxic activity. 相似文献