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101.
102.
Background
Text-mining can assist biomedical researchers in reducing information overload by extracting useful knowledge from large collections of text. We developed a novel text-mining method based on analyzing the network structure created by symbol co-occurrences as a way to extend the capabilities of knowledge extraction. The method was applied to the task of automatic gene and protein name synonym extraction. 相似文献103.
A novel disorder caused by defective biosynthesis of N-linked oligosaccharides due to glucosidase I deficiency 总被引:11,自引:0,他引:11 下载免费PDF全文
De Praeter CM Gerwig GJ Bause E Nuytinck LK Vliegenthart JF Breuer W Kamerling JP Espeel MF Martin JJ De Paepe AM Chan NW Dacremont GA Van Coster RN 《American journal of human genetics》2000,66(6):1744-1756
Glucosidase I is an important enzyme in N-linked glycoprotein processing, removing specifically distal alpha-1,2-linked glucose from the Glc3Man9GlcNAc2 precursor after its en bloc transfer from dolichyl diphosphate to a nascent polypeptide chain in the endoplasmic reticulum. We have identified a glucosidase I defect in a neonate with severe generalized hypotonia and dysmorphic features. The clinical course was progressive and was characterized by the occurrence of hepatomegaly, hypoventilation, feeding problems, seizures, and fatal outcome at age 74 d. The accumulation of the tetrasaccharide Glc(alpha1-2)Glc(alpha1-3)Glc(alpha1-3)Man in the patient's urine indicated a glycosylation disorder. Enzymological studies on liver tissue and cultured skin fibroblasts revealed a severe glucosidase I deficiency. The residual activity was <3% of that of controls. Glucosidase I activities in cultured skin fibroblasts from both parents were found to be 50% of those of controls. Tissues from the patient subjected to SDS-PAGE followed by immunoblotting revealed strongly decreased amounts of glucosidase I protein in the homogenate of the liver, and a less-severe decrease in cultured skin fibroblasts. Molecular studies showed that the patient was a compound heterozygote for two missense mutations in the glucosidase I gene: (1) one allele harbored a G-->C transition at nucleotide (nt) 1587, resulting in the substitution of Arg at position 486 by Thr (R486T), and (2) on the other allele a T-->C transition at nt 2085 resulted in the substitution of Phe at position 652 by Leu (F652L). The mother was heterozygous for the G-->C transition, whereas the father was heterozygous for the T-->C transition. These base changes were not seen in 100 control DNA samples. A causal relationship between the alpha-glucosidase I deficiency and the disease is postulated. 相似文献
104.
105.
J M Williams R Loertscher T Cotner M Reddish H M Shapiro C B Carpenter J L Strominger T B Strom 《Journal of immunology (Baltimore, Md. : 1950)》1984,132(5):2330-2337
This study provides direct correlation via dual parameter flow cytometry (simultaneous assessment of immunofluorescence and DNA content) between mixed lymphocyte reaction (MLR) responder cell entry into the S/G2/M phases of the cell cycle with the kinetics of expression of two activation-associated cell surface proteins, Tac (IL 2 receptor) and 4F2 (unknown metabolic function). A small population of activated cells was identifiable by expression of both Tac and 4F2 antigens before peak DNA synthesis in the MLR. This population of activation antigen-positive cells expanded linearly in size from days 3 to 7 of culture. Treatment of immature MLR cultures with anti-4F2 Mab and complement (C) before DNA synthesis (treatment on day 3, peak DNA synthesis on days 5 to 6) resulted in blunted proliferation and activation antigen expression when the same culture was analyzed after maturation on day 6, indicating that the activated population had been previously detected and removed by anti-4F2 Mab + C. The 4F2 antigen was expressed on a greater percentage of cells in the MLR at all times (days 3 to 9) than was Tac, was present on virtually all S/G2/M phase responder cells, and a large fraction of cells remained intensely 4F2+ subsequent to peak DNA synthesis. In contrast, after initially preceding responder cell entry into the S phase of the cell cycle, the kinetics of Tac antigen expression closely paralleled the kinetics of responder cell proliferation. A subpopulation of cycling responder cells was noted in all MLR cultures studied that expressed Tac antigen weakly or not at all. Cells within both T4 and T8 cell subsets proliferate with similar kinetics in response to alloantigen. The possibility that activation antigens can be utilized to study effector cell generation in the MLR and that this flow cytometric technique may be utilized to analyze the response to various alloantigens is discussed. 相似文献
106.
Wells AD Li XC Strom TB Turka LA 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2001,356(1409):617-623
The apoptotic deletion of thymocytes that express self-reactive antigen receptors is the basis of central (thymic) self-tolerance. However, it is clear that some autoreactive T cells escape deletion in the thymus and exist as mature lymphocytes in the periphery. Therefore, peripheral mechanisms of tolerance are also crucial, and failure of these peripheral mechanisms leads to autoimmunity. Clonal deletion, clonal anergy and immunoregulation and/or suppression have been suggested as mechanisms by which 'inappropriate' T-lymphocyte responses may be controlled in the periphery. Peripheral clonal deletion, which involves the apoptotic elimination of lymphocytes, is critical for T-cell homeostasis during normal immune responses, and is recognized as an important process by which self-tolerance is maintained. Transplantation of foreign tissue into an adult host represents a special case of 'inappropriate' T-cell reactivity that is subject to the same central and peripheral tolerance mechanisms that control reactivity against self. In this case, the unusually high frequency of naive T cells able to recognize and respond against non-self-allogeneic major histocompatibility complex (MHC) antigens leads to an exceptionally large pool of pathogenic effector lymphocytes that must be controlled if graft rejection is to be avoided. A great deal of effort has been directed toward understanding the role of clonal anergy and/or active immunoregulation in the induction of peripheral transplantation tolerance but, until recently, relatively little progress had been made towards defining the potential contribution of clonal deletion. Here, we outline recent data that define a clear requirement for deletion in the induction of peripheral transplantation tolerance across MHC barriers, and discuss the potential implications of these results in the context of current treatment modalities used in the clinical transplantation setting. 相似文献
107.
Prevalence,comorbidities and mortality of toxic shock syndrome in children and adults in the USA 下载免费PDF全文
108.
Renibacterium salmoninarum is a gram-positive bacterium responsible for bacterial kidney disease of salmon and trout. R. salmoninarum has two identical copies of the gene encoding major soluble antigen (MSA), an immunodominant, extracellular protein. To determine whether one or both copies of msa are expressed, reporter plasmids encoding a fusion of MSA and green fluorescent protein controlled by 0.6 kb of promoter region from msa1 or msa2 were constructed and introduced into R. salmoninarum. Single copies of the reporter plasmids integrated into the chromosome by homologous recombination. Expression of mRNA and protein from the integrated plasmids was detected, and transformed cells were fluorescent, demonstrating that both msa1 and msa2 are expressed under in vitro conditions. This is the first report of successful transformation and homologous recombination in R. salmoninarum. 相似文献
109.
This investigation examined the exposure of Egyptian infants to Aflatoxin M1 (AfM1) and of lactating mothers to Aflatoxin B1, using AfM1 in human milk as a biomarker for exposure to AfB1. The presence of ochratoxin A (OA) in human milk was also investigated to determine the levels of infants exposure to OA
from human milk. The results indicated that AfM1 was found in 66 (55 %) of 120 human milk samples with a mean of 0.3 ± 0.53 ng/mL (range 0.02 to 2.09 ng/mL). OA was found
in 43 (35.8 %) of 120 human milk samples with a mean of 21.1 ± 13.7 ng/mL (range 5.07 to 45.01 ng/mL), which will cause a
daily intake of OA from human milk exceeding the suggested tolerable dose of 5 ng/kg-1 of OA body weight. On the other side AfM1 was found in 25 % of blood samples (5 out of 20 samples), at a mean of 1.18 ng/mL, but it was detected only in one urine
sample (1 out of 20 samples). OA was detected only in 2 out of 13 blood samples (15.4 %) with an average 3.67 ng/mL. Whereas
OA was not detected in all analyzed urine samples. 相似文献
110.
A Mutation in VPS35, Encoding a Subunit of the Retromer Complex, Causes Late-Onset Parkinson Disease
Alexander Zimprich Anna Benet-Pagès Walter Struhal Elisabeth Graf Sebastian H. Eck Marc N. Offman Dietrich Haubenberger Sabine Spielberger Eva C. Schulte Peter Lichtner Shaila C. Rossle Norman Klopp Elisabeth Wolf Klaus Seppi Walter Pirker Stefan Presslauer Brit Mollenhauer Regina Katzenschlager Thomas Foki Christoph Hotzy Eva Reinthaler Ashot Harutyunyan Robert Kralovics Annette Peters Fritz Zimprich Thomas Brücke Werner Poewe Eduard Auff Claudia Trenkwalder Burkhard Rost Gerhard Ransmayr Juliane Winkelmann Thomas Meitinger Tim M. Strom 《American journal of human genetics》2011,(1):168-175
To identify rare causal variants in late-onset Parkinson disease (PD), we investigated an Austrian family with 16 affected individuals by exome sequencing. We found a missense mutation, c.1858G>A (p.Asp620Asn), in the VPS35 gene in all seven affected family members who are alive. By screening additional PD cases, we saw the same variant cosegregating with the disease in an autosomal-dominant mode with high but incomplete penetrance in two further families with five and ten affected members, respectively. The mean age of onset in the affected individuals was 53 years. Genotyping showed that the shared haplotype extends across 65 kilobases around VPS35. Screening the entire VPS35 coding sequence in an additional 860 cases and 1014 controls revealed six further nonsynonymous missense variants. Three were only present in cases, two were only present in controls, and one was present in cases and controls. The familial mutation p.Asp620Asn and a further variant, c.1570C>T (p.Arg524Trp), detected in a sporadic PD case were predicted to be damaging by sequence-based and molecular-dynamics analyses. VPS35 is a component of the retromer complex and mediates retrograde transport between endosomes and the trans-Golgi network, and it has recently been found to be involved in Alzheimer disease. 相似文献