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排序方式: 共有387条查询结果,搜索用时 15 毫秒
21.
The redox unbalance in erythrocytes has been found to contribute significantly in the development of anemia in visceral leishmaniasis (VL). The present study revealed enhanced production of reactive oxygen species (ROS) and gradual depletion of alpha-tocopherol and ascorbate in the erythrocytes of infected animals. The response of erythrocytes to chronic treatment with antioxidants was studied in hamsters during leishmanial infection. Treatment with a combination of alpha-tocopherol and ascorbate proved to be the most effective preventive for the proteolytic degradation of erythrocyte membrane. Erythrocytes from infected animals were thermally more sensitive compared to the control ones. Combination of both antioxidants was most successful in resisting heat induced structural defects in the cells. Cross-linking of membrane proteins subsequent to oxidative damage in the red cells was accompanied by the formation of high molecular weight protein band at the top of the resolving gel in the presence of the cross-linking agent dimethyladepimidate (DMA). Marked inhibition of cross-linking was observed with combination of both antioxidants. Treatment with alpha-tocopherol and ascorbate together could withstand osmotic lysis of erythrocytes in the infected animals very efficiently. Decreased hemoglobin (Hb) level was successfully replenished and was coupled with significant increase in the life span of red cells after treating the animals with both antioxidants. Results indicate better efficacy of the combination therapy with alpha-tocopherol and ascorbate in protecting the erythrocytes from structural and functional damages during leishmanial infection. 相似文献
22.
Wang Q Montmain G Ruano E Upadhyaya M Dudley S Liskay RM Thibodeau SN Puisieux A 《Human genetics》2003,112(2):117-123
DNA mismatch repair (MMR) is the process by which incorrectly paired DNA nucleotides are recognized and repaired. A germline mutation in one of the genes involved in the process may be responsible for a dominantly inherited cancer syndrome, hereditary nonpolyposis colon cancer. Cancer progression in predisposed individuals results from the somatic inactivation of the normal copy of the MMR gene, leading to a mutator phenotype affecting preferentially repeat sequences (microsatellite instability, MSI). Recently, we identified children with a constitutional deficiency of MMR activity attributable to a mutation in the h MLH1 gene. These children exhibited a constitutional genetic instability associated with clinical features of de novo neurofibromatosis type 1 (NF1) and early onset of extracolonic cancer. Based on these observations, we hypothesized that somatic NF1 gene mutation was a frequent and possibly early event in MMR-deficient cells. To test this hypothesis, we screened for NF1 mutations in cancer cells. Genetic alterations were identified in five out of ten tumor cell lines with MSI, whereas five MMR-proficient tumor cell lines expressed a wild-type NF1 gene. Somatic NF1 mutations were also detected in two primary tumors exhibiting an MSI phenotype. Finally, a 35-bp deletion in the murine Nf1 coding region was identified in mlh1-/- mouse embryonic fibroblasts. These observations demonstrate that the NF1 gene is a mutational target of MMR deficiency and suggest that its inactivation is an important step of the malignant progression of MMR-deficient cells. 相似文献
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24.
Wu SL Amato H Biringer R Choudhary G Shieh P Hancock WS 《Journal of proteome research》2002,1(5):459-465
This paper describes the profiling of human growth hormone (hGH) in human plasma in order to assess the dynamic range of the ion-trap mass spectrometer for proteomic studies of complex biological samples. Human growth hormone is an example of a low-level plasma protein in vivo, present at subfemtomole levels. This study was performed on a plasma sample in which hGH has been spiked at 10-fold above the natural level, that is approximately 16 pg/microL of plasma. Initially, the measurement was carried out without any sample enrichment and consisted of the following steps: the full set of plasma proteins were reduced, alkylated, and digested with trypsin, and the resulting peptides were separated on a capillary C-18 column and then detected by ion-trap mass spectrometry (1D LC/MS). In addition, this study provided a global view of the serum proteome with over 200 plasma proteins being preliminarily identified. In the MS/MS analysis, hGH was detected by characterization of the first tryptic peptide (T1). The initial identification was confirmed by alternative approaches, which also allowed the evaluation of different sample purification protocols. First, the plasma sample containing hGH was fractionated on a reversed-phase HPLC column and digested, and hGH could now be identified by MS/MS measurements of two tryptic peptides (T1 and T4) by the same 1D LC/MS protocol. In addition, the assignment of peptide identity was made with higher certainty (as measured by an algorithm score). The plasma sample was also fractionated by 1D and 2D gel electrophoresis, the selected bands were digested and analyzed again by the 1D LC/MS protocol. In both cases using the gel prepurifications, hGH was identified with additional peptides. Finally, the plasma sample was analyzed by 2D chromatography (ion exchange and reversed phase) on a new instrumental platform (ProteomeX), and hGH was identified by the observation of five tryptic peptides. In conclusion, these experiments were able to detect growth hormone in the low femtomole level with a dynamic range of 1 in 40 000 by several independent approaches. The amount of growth hormone, while 10-fold above normal in vivo levels, represents concentrations that may be present in disease states (such as acromegaly) and also in doping control measurements. These studies have demonstrated that shotgun sequencing approaches (LC/MS/MS) not only can profile high-abundance proteins in complex biological fluids but also have the potential to identify and quantitate low-level proteins present in such complex mixtures without extensive prepurification protocols. A key to such studies, however, is to use targeted approaches that reduce the complexity of the solute mixture that is presented to the mass spectrometer at a given time point. The various sample preparation protocols described here all improved the quality of the hGH measurement, although in this study the 2D chromatographic approach gave the greatest sequence coverage. 相似文献
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26.
The Sos1 and Sos2 Ras-specific exchange factors: differences in placental expression and signaling properties
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Qian X Esteban L Vass WC Upadhyaya C Papageorge AG Yienger K Ward JM Lowy DR Santos E 《The EMBO journal》2000,19(4):642-654
Targeted disruption of both alleles of mouse sos1, which encodes a Ras-specific exchange factor, conferred mid-gestational embryonic lethality that was secondary to impaired placental development and was associated with very low placental ERK activity. The trophoblastic layers of sos1(-/-) embryos were poorly developed, correlating with high sos1 expression in wild-type trophoblasts. A sos1(-/-) cell line, which expressed readily detectable levels of the closely related Sos2 protein, formed complexes between Sos2, epidermal growth factor receptor (EGFR) and Shc efficiently, gave normal Ras.GTP and ERK responses when treated with EGF for < or =10 min and was transformed readily by activated Ras. However, the sos1(-/-) cells were resistant to transformation by v-Src or by overexpressed EGFR and continuous EGF treatment, unlike sos1(+/-) or wild-type cells. This correlated with Sos2 binding less efficiently than Sos1 to EGFR and Shc in cells treated with EGF for > or =90 min or to v-Src and Shc in v-Src-expressing cells, and with less ERK activity. We conclude that Sos1 participates in both short- and long-term signaling, while Sos2-dependent signals are predominantly short-term. 相似文献
27.
Yajing He Zhaowei Meng Qiang Jia Fang Hu Xianghui He Jian Tan Guizhi Zhang Xue Li Jianping Zhang Qing Zhang Li Liu Lili Zhao Jing Li Yuling Wang Yumei Qian Shuling Hou Hua Liu Sheng Wang Renfei Wang Wei Zheng Tianpeng Hu Na Liu Arun Upadhyaya Yang Liu 《PloS one》2015,10(6)
Objective
We aimed to measure prevalence of sleep disturbance in patients with differentiated thyroid cancer (DTC) by calculating Pittsburgh Sleep Quality Index (PSQI), and compare these data with patients with benign thyroid nodules or normal participants.Methods
Three groups of patients participated in this cross-sectional study. In the first group, 162 patients with DTC received total thyroidectomy, and then 131I therapy. The second group consisted of 84 patients with benign thyroid nodules, who received partial thyroidectomy. The third group was 78 normal healthy control cases. PSQI was used to assess the sleep quality. Inter-group differences were analyzed by Kruskal-Wallis test or independent samples T test. χ2 test was also used to check prevalence differences of poor sleep quality among the groups. Differences of PSQI score and poor sleep quality prevalence before and after 131I therapy in the same group of DTC participants were analyzed by paired T test and Mcnemar''s test.Results
Higher PSQI score (7.59 ± 4.21) and higher rate of poor sleep quality (54.32%) were shown in DTC patients than in any other group. After 131I therapy, PSQI score and prevalence of poor sleep quality in DTC patients increased significantly to 8.78 ± 4.72 and 70.99%. Then DTC patients were divided into two subgroups based on their metastatic status. DTC patients with metastasis (87/162 cases, 53.70%) had significantly higher PSQI score (10.87 ± 5.18) and higher prevalence of poor sleep quality (79.31%).Conclusion
DTC patients suffer from sleep disturbance, 131I therapy and awareness of metastatic status could worsen sleep problem. Psychological fear of cancer, nuclear medicine therapy and metastasis could be one major underlying reason. Longitude and interventional studies are necessary for further investigations. 相似文献28.
29.
Aminopeptidase N (APN) isoforms were identified as candidate receptors for Bacillus thuringiensis Cry toxins from the midgut of several insect species. In this study a partial cDNA encoding aminopeptidase (slfbAPN) was
cloned from fat body of the moth Spodoptera litura. In the deduced amino acid sequence the characteristic metallopeptidase sequences, HEXXHX18E and GAMENWG were conserved but the sequence showed only 33–39% identity to other insect APNs, which were also reported to
be Cry toxin receptors. The presence of a putative GPI anchor signal sequence at the C-terminus indicated that it is a membrane-anchored protein. The slfbAPN expression was restricted to the fat body as suggested
by northern blot analysis of different tissues. Biochemical analyses including immunoblotting, ligand blotting and lectin
blotting, demonstrated that slfbAPN is a membrane-anchored glycoprotein in the fat body and it binds to Cry toxins.
The nucleotide sequence shown here has been submitted to the GenBank sequence data bank and is available under accession number
EF372603. 相似文献
30.
Pandey GK Pandey A Reddy VS Deswal R Bhattacharya A Upadhyaya KC Sopory SK 《Journal of biosciences》2007,32(2):251-260
Entamoeba histolytica contains a novel calcium-binding protein like calmodulin, which was discovered earlier, and we have reported the presence
of its homologue(s) and a dependent protein kinase in plants. To understand the functions of these in plants, a cDNA encoding
a calcium-binding protein isolated from Entamoeba histolytica (EhCaBP) was cloned into vector pBI121 in antisense orientation and transgenic tobacco plants were raised. These plants showed
variation in several phenotypic characters, of which two distinct features, more greenness and leaf thickness, were inherited
in subsequent generations. The increase in the level of total chlorophyll in different plants ranged from 60% to 70%. There
was no major change in chloroplast structure and in the protein level of D1, D2, LHCP and RuBP carboxylase. These morphological
changes were not seen in antisense calmodulin transgenic tobacco plants, nor was the calmodulin level altered in EhCaBP antisense
plants.
The results of this paper have been granted US Patent No. 6,791,009. 相似文献