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排序方式: 共有534条查询结果,搜索用时 31 毫秒
61.
Molecular basis of the heterogeneity of expression of glycosyl phosphatidylinositol anchored proteins in paroxysmal nocturnal hemoglobinuria 总被引:2,自引:3,他引:2
Endo M; Ware RE; Vreeke TM; Singh SP; Howard TA; Tomita A; Holguin MH; Parker CJ 《Blood》1996,87(6):2546-2557
The purpose of these studies was to determine the molecular basis of the phenotypic mosaicism that is a defining feature of paroxysmal nocturnal hemoglobinuria (PNH). Analysis of T cell clones from a female patient revealed four distinct phenotypes based on surface expression of glycosyl phosphatidylinositol-anchored proteins (GPI-AP). When PIG-A (the gene that is mutant in PNH) from these clones was analyzed, four discrete somatic mutations were identified. Analysis of X chromosomal inactivation among the abnormal T cell clones was consistent with polyclonality. Together, these studies demonstrate that the phenotypic mosaicism that is characteristic of PNH is a consequence of genotypic mosaicism and that, at least in this case, PNH is a polyclonal rather than a monoclonal disease. That four distinct somatic mutations were present in a single patient suggests that in conditions that predispose to PNH PIG-A may be hypermutable. 相似文献
62.
In this investigation, we studied the importance of cellular glutathione (GSH) in the hexose monophosphate shunt (HMPS) activity of unstimulated human erythrocytes and the mechanism by which pyruvate stimulates the HMPS. The rate of HMPS activity was measured by the production of radioactive CO2 from 14C-1-glucose or 14C-1-ribose using a vibrating reed electrometer and ionization chamber. HMPS activity was not significantly impaired by N-ethylmaleimide (NEM) in concentrations which bound all red cell GSH. Red cells incubated under carbon monoxide (CO), an experimental condition which eliminates peroxide production, still had HMPS activity which was 44% of the value under air. Pyruvate stimulation of the HMPS was unaffected by doses of NEM which bound all cellular GSH or by incubation under CO. These data indicated that pyruvate stimulation of the HMPS occurs by pathways which do not involve peroxide formation, GSH, or oxygen. This study indicates that sulfhydryl blockade of GSH does not necessarily inhibit HMPS activity and that HMPS activity in red cells may respond to reactions not linked directly to glutathione reduction. 相似文献
63.
Cholongitas E Katsoudas S Spyros K Dourakis S Spyros D 《European Journal of Internal Medicine》2005,16(1):59-60
Henoch-Schonlein purpura (HSP) is a systemic vasculitis that occurs most often in children and rarely follows exposure to drugs or other environmental factors. Aloe is one of the most widely used traditional remedies and has been associated with gastrointestinal and renal complications. We report a case of HSP in an adult patient who had previously received the herb Aloe vera. 相似文献
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The biochemical and clinical consequences of 2'-deoxycoformycin in refractory lymphoproliferative malignancy 总被引:4,自引:1,他引:4
Grever MR; Siaw MF; Jacob WF; Neidhart JA; Miser JS; Coleman MS; Hutton JJ; Balcerzak SP 《Blood》1981,57(3):406-417
A deficiency of adenosine deaminase, an enzyme important in purine nucleoside catabolism, is associated with a severe combined immunodeficiency disease in children. Inhibition of this enzyme in vitro and in vivo results in an impairment in lymphoblast proliferation. We have investigated the pharmacologic inhibition of this enzyme by 2'-deoxycoformycin in 15 patients with hematologic malignancies. Biochemical consequences of the administration of this agent were closely monitored in erythrocytes, nucleated peripheral blood and bone marrow cells, serum, and urine. A marked rise in erythrocyte dATP was accompanied by a depletion of ATP in those patients exhibiting toxicity. Most patients excreted large amounts of deoxyadenosine but not adenosine in the urine. Serum deoxyadenosine rose in patients demonstrating a marked decrease in cell mass. The biochemical disturbances and clinical toxicity, including hepatic, renal, and conjunctival abnormalities, were usually reversible. Central nervous system toxicity, which potentially was the most serious consequence, was associated with high erythrocyte dATP/ATP ratios and high levels of cerebrospinal fluid deoxyadenosine. In patients with lymphoma and leukemia, objective responses were observed but were short- lived. Patients with chronic lymphocytic leukemia receiving weekly low doses of the drug demonstrated minimal toxicity and some efficacy. The chemotherapeutic potential o 2'-deoxycoformycin, as either a single agent or in combination with Ara-A, merits further exploration. 相似文献
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SP Attard-Montalto C Camacho-Hübner AM Cotterill L D'Souza-Li S Daley K Bartlett D Halliday OB Eden 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(1):54-60
Changes in insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding proteins (IGFBPs) were correlated with protein synthesis and breakdown using [1- 13C]leucine before chemotherapy and during subsequent febrile neutropenia (FN) in eight children with cancer, aged 6.3–17.5 y. IGF-I levels were similar to age-matched controls before chemotherapy (mean ±SEM: 250 ±28 and 228 ±22 μg l-1, respectively). During FN, IGF-I fell to 156 ±22 /ng l -1(p= 0:02), and rose to 276 ±27 μ g l -1 with recovery at 6 months (p = 0:004). Similarly, IGFBP-3 decreased from 4.0 ±0.2mgl-1 before chemotherapy to 3.0 ±0.3 mgl-1 during FN (p= 0:01), and returned to 4.1 ±0.2mgl -1 at 6 months (p= 0:01). IGF-I correlated with IGFBP-3 (r=+0:7, p <0:001). Scanning densitometry showed a decrease in IGFBP-3 from 94 to 54% during FN, when the presence of IGFBP-3 protease activity was observed. Compared with normal human serum, IGFBP-2 was elevated throughout the study. IGFBP-1 increased from 14.6 ±3.5 to 30.6 ±2.8/ngl-1 (p = 0:004), whereas serum insulin decreased from 26.5 ±6.8 to 7.8 ±0.8 mUl-1 (p= 0:03) before and during FN, respectively. Whilst IGF-I and IGFBP-3 fell, daytime growth hormone increased from 3.3 ±0.6 to 6.7±0.8mUl -1 (p= 0:01), and cortisol from 197 ±48 to 594±98nmoll -1 (p = 0:005). Albumin decreased from 47 ±2 to 38 ±2gl-1 (p= 0:004) and improved to 47 ±2gl-1 with recovery (p= 0:003). Protein synthesis increased from 4.5 ±0.4 to 5.0 ±0.6gkg-1 d-1 before chemotherapy and during FN, while protein breakdown rose from 5.4 ±0.4 to 6.3 ±0.4kg-1d-1. Increasing protein breakdown was related to falling IGF-I and IGFBP-3 levels. Modification of IGFBP-3 by circulating proteolytic activity may alter IGF bioavailability, allowing protein synthesis to increase during periods of severe catabolic stress. 相似文献
70.
Objective: To identify risk factors for development of dehydration in under five year olds with acute watery diarrhoea.Design: Hospital based unmatched case-control study.Setting: Diarrhoea Treatment Unit, Government Medical College Hospital, Nagpur, India.Participants: The study included 387 cases of diarrhoea having severe or moderate dehydration and 387 controls suffering from diarrhoea with mild or no dehydration.Risk factors: The study included infancy, female sex, religion, residing in urban slums or rural area, under nutrition, cessation of breast feeding during diarrhoeal episode, fluid intake decreased/stopped during diarrhoea, ORS not received, home available fluids (HAF) not received, both ORS and HAF not received, non-washing of hands by mother before preparation of food, after defaecation, after disposal of faeces, history of measles in the previous six months, frequency of stools >8/d, frequency of vomiting more than twice per day and temperature more than 99°F, as risk factors for development of dehydration.Statistical analysis: Univariate analysis included OR, 95% CI for OR and Chi-square test. Multivariate analysis was carried out by unconditional multiple logistic regression (MLR).Results: This study identified the significance of infancy, religion, severe undernutrition, non-washing of hands by mother before preparation of food, frequency of stool >8/d, frequency of vomiting >2/d, history of measles in previous six months, withdrawal of breast feeding during diarrhoea, withdrawal of fluids during diarrhoea and not giving ORS, HAF or both during diarrhoea, in the outcome of development of moderate or severe dehydration.Conclusions: Timely intervention in the preventable risk factors included in this study may prevent the development of moderate or severe dehydration in the children suffering form acute watery diarrhoea. 相似文献