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Biomedical subjects

X He

Publications and source records attributed to X He.

At least 343 records · Page 19Linked to original sources
PubMed1996

[Alteration of mRNA transcripts of rat Sertoli cell secreted proteins and Leydig cell LH/CG-R protein following glycosides of Tripterigium Wilfordii Hook administration].

Our studies were undertaken to assess the male antifertility mechanism of the total glycosides extracted from Tripterigium Wilfordii Hook. f. (GTW). In experimental group I, GTW was given by gastric gavage at a dose of 30 mg/kg per day for 35 days. In experimental group I, GTW was given in the same way at a dose of 10 mg/kg per day for 49 days. The transcripts level analysis indicated that in all the experimental groups ABP, SGP-2 and LH/CG-R mRNA were increased. Two ABP and two LH/CG-R mRNA transcripts with respective molecular sizes of 1.7 kb, 2.3 kb and 1.2 kb, 4.4 kb were identified. ABP and LH/ CG-R mRNA with 1.7 kb and 1.2 kb increased, while those with 2.3 and 4.4 kb remained unchanged. In addition, the changes of different proteins at the mRNA level were shown to be GTW dose-dependent. The morphological features of germ cell degeneration and appearance of germ cells in tubular lumen suggest that the increases in transcripts level of three proteins in testis may not be directly associated with the effect of GTW. The question whether GTW interfere with the function of sertoli cells and leydig cells would be study.

Androgen-Binding Protein↗
PubMed1996

[Etoposide combination chemotherapy for malignant lymphoma: a report of 91 cases].

From August 1984 to August 1994 ninety-one caese of malignant lymphoma (NHL 84 casese, HD 7 cases) were treated with Etoposide (VP-16) combinationn chemotherapy. In 70 evaluable patients, 18 achieved CR, 35 PR, total response rate was 75.7%, response time (RT) 1-79 months, medium response time (MRT) 9 months, survival time (ST) 2-79 months, medium survival time (MST) 12 months. The therapeutic efficacy was better than VP-16 alone. The major side effects were myelosuppression and gastrointestinal toxicity. In COPEP, CHEP, PEP and IEP regimens, best result was seen in COPEP (CTX + VCR + PYM + VP-16 + PDN), with a response rate of 93%. Authors suggest that COPEP protocol could be the first line treatment for patients with malignant lymphoma who did not tolerate anthracycline drugs and the second line treatment for anthracycline-resistant patients.

Adolescent↗
PubMed1996

Study on inhibition of pancreatic exocrine secretion by somatostatin in rats.

We used a potent and specific monoclonal antibody to somatostatin to test the physiologic inhibitory role of the tetradecapeptide somatostatin on pancreatic secretion. Somatostatin immunoneutralization increased both the total amylase and volume of pancreatic secretion. Cholecystokinin-A receptor antagonism abolished the stimulatory effect of somatostatin immunoneutralization. We conclude that somatostatin tonically inhibits, pancreatic secretion in fasted rats via inhibition of the release or action of cholecystokinin. Furthermore, the source of these peptides is likely islet delta cells and intrapancreatic neurons, respectively.

Amylases↗
PubMed1996

Rat exocrine pancreatic secretion by vagal stimulation occurs via multiple mediators.

The vagus is a mixed nerve containing cholinerrgic and non-cholinergic neurons. Vagal fibers interact with peptidergic neurons of the enteric nervous system which stain immunohistochemically for cholecystokinin, vasoactive intestinal polypeptide, and gastrin releasing peptide. The contribution of these peptidergic neurons in the pancreatic response to vagal stimulation is unknown. We tested the effect of specific inhibitor of these stimulants against vagally mediated exocrine secretion in rats. The response to vagal stimulation was blocked significantly by each of the following: the ganglionic blocker hexamethonium (100% inhibition); the muscarinic, cholinergic blocker atropine (85% inhibition); the specific cholecystokinin-A receptor blocker (91% inhibition); and a vasoactive intestinal polypeptide polyclonal antibody (89% inhibition). This observation is consistent with the hypothesis that potentiating interactions among several agonists mediate the vagal response. Our study, however, dose not exclude acetylcholine as the final common mediator.

Amylases↗
PubMed1996

[Application of PCR-SSCP technique in detection of rpoB gene mutation in rifampin-resistant Mycobacterium tuberculosis].

OBJECTIVE: To evaluate rpoB gene mutation in rifampin-resistant Mycobacterium tuberculosis and its relationship with rifampin resistance. METHODS: Forty clinical isolates of Mycobacterium tuberculosis were analyzed by PCR-SSCP technique, with H37Rv reference strains as control group. RESULTS: The sensitivity of amplication products of 411bp and 258bp were found to be 5 pg/microliters, 500 organisms per milliliter and 1 pg/microliter, 500 organisms per milliliter respectively. rpoB gene belongs to genus specificity. Characteristics of SSCP graph of 258bp fragment: Ten sensitive strains were the same as H37 Rv. Thirty strains of rifampin-resistant or multidrug resistance, including rifampin, were different from H37Rv except for three strains. Positive rate was 90%, while specificity 100%. CONCLUSIONS: Results showed that PCR-SSCP technique could detect rPOB gene mutation, which might associate with rifampin resistance and be helpful to rapid detection and research of rifampin-resistant Mycobacterium tuberculosis.

Antibiotics, Antitubercular↗
PubMed1996

[Detection of M. tuberculosis streptomycin-resistant gene].

OBJECTIVE: To observe the mutations of rpsL gene in M. tuberculosis streptomycin-resistant isolates, and to develop a new method for detecting drug resistance. METHOD: Detecting the rpsL genes with PCR-SSCP and analyzing their codons 43 by PCR-RFLP. RESULTS: Strain H37Rv was used as a control. In 22 M. tuberculosis clinical isolates, the rpsL PCR fragments from 5 drug-susceptible isolates had no differences in the SSCP profiles with strain H37Rv, and were restricted by Mbo II. 11 of the 13 streptomycin-resistant isolates showed apparent differences in the SSCP profiles and were not digested with Mbo II. 1 of the 4 other drug-resistant isolates also had apparent SSCP differences and was not digested by Mbo II. CONCLUSIONS: The results suggested that the rpsL gene mutation was frequently observed in M. tuberculosis streptomycin-resistant isolates, and usually situated at codon 43, PCR-SSCP and PCR-RFLP might become a simple, rapid and reliable diagnostic test for drug resistance.

Antibiotics, Antitubercular↗
PubMed1995

Alternative splicing of HLA class I transcripts induced by IFN-gamma and TNF in fibroblasts: release of soluble HLA class I heavy chain and an associate protein.

FS-4 fibroblasts were found to produce 37-kDa HLA class I heavy chain in response to IFN-gamma or TNF in a time- and dose-dependent fashion, and a synergism between IFN-gamma and TNF was observed. Immunoprecipitation of IFN-gamma- or TNF-induced FS-4 cell culture supernatants by mAb A1.4 revealed an additional 33-kDa protein in association with the 37-kDa heavy chain. The 33-kDa protein appeared to be expressed in a 38-kDa form on the membrane of FS-4 cells induced by IFN-gamma or TNF, as A1.4 immunoprecipitated the 38-kDa band in association with the 44-kDa transmembrane HLA class I heavy chain. Release of the 37-kDa heavy chain could well be due to an alternative RNA splicing with the deletion of exon 5 encoding the hydrophobic transmembrane region of membrane-anchored HLA class I heavy chain. Northern blot analysis and S1 nuclease protection assay suggested the existence of HLA class I heavy chain mRNA lacking exon 5 in IFN-gamma- or TNF-induced FS-4 cells. Southern blot analysis on the products of reverse transcription-polymerase chain reaction amplification from cytoplasmic RNA confirmed induction of alternative splicing by these cytokines. Our results suggest that cytokine-induced production of soluble HLA class I molecules may play important roles in the regulation of T cell interaction with antigen-presenting cells.

Alternative Splicing↗
PubMed1995

Glycogen synthase kinase-3 and dorsoventral patterning in Xenopus embryos.

Glycogen synthase kinase 3 (GSK-3) is homologous to the product of the Drosophila gene shaggy (zeste-white 3), which is required for signalling by wingless during Drosophila development. To test whether GSK-3 is also involved in vertebrate pattern formation, its role was investigated during early Xenopus development. It was found that dominant-negative GSK-3 mutants induced dorsal differentiation, whereas wild-type GSK-3 induced ventralization. These results indicate that GSK-3 is required for ventral differentiation, and suggest that dorsal differentiation may involve the suppression of GSK-3 activity by a wingless/wnt-related signal.

Animals↗
PubMed1995

Expression and functional characterization of chimeras between human and bovine vitamin-K-dependent protein-S-defining modules important for the species specificity of the activated protein C cofactor activity.

Vitamin-K-dependent protein S is an anticoagulant plasma protein functioning as a cofactor to activated protein C (APC) in the degradation of factors Va and VIIIa. The APC-cofactor function of protein S is species specific, as human protein S potentiates the anticoagulant activity of human but not that of bovine APC, whereas bovine protein S is a cofactor to APC from both species. To elucidate which modules in protein S determine the species specificity, in vitro mutagenesis was used to construct six recombinant chimeric molecules between human and bovine protein S. Wild-type human and bovine protein S and the chimeras were expressed in 293 cells and the recombinant proteins purified by monoclonal antibody affinity chromatography. The recombinant proteins were found to be post-translationally modified, they bound C4b-binding protein and were functionally active as cofactors to APC. Chimeras having both the thrombin-sensitive region (TSR) and the first epidermal-growth-factor-(EGF)-like module of bovine origin expressed APC-cofactor activity similar to that of bovine protein S. Those chimeras, in which TSR or EGF1 derived from different species, manifested APC-cofactor activity similar to that of human protein S, i.e. they did not express cofactor activity to bovine APC. These data indicate that sequence differences in the TSR and EGF1 of human and bovine protein S cause the species specificity of the APC-cofactor activity. The data support the concept that these two modules of protein S interact with APC on the surface of negatively charged phospholipids.

Amino Acid Sequence↗
PubMed1995

Analysis of the role of CD4+ T-cells during murine cytomegalovirus infection in different strains of mice.

We examined the role of CD4+ T-cells in peritoneal exudate cells (PECs) during the course of acute murine cytomegalovirus (MCMV) infection in two strains of mice. Cell counts of PECs and cytofluorometric analysis showed that C57BL/6, a resistant strain, had more CD4+ T-cells than BALB/c, a susceptible strain, after intraperitoneal infection of 3 x 10(3) PFU of the Smith strain of MCMV, though both strains had an equivalent number of CD8+ T-cells. CD4+ T-cells of both strains expressed mRNA of IFN-gamma, IL-2, and IL-4 on days 5 and 7 after infection, with much higher expression of these cytokines in C57BL/6 than in BALB/c. At the same time point after infection, macrophages were shown to express mRNA of IL-1 alpha and TNF-alpha with higher expression of IL-1 alpha in C57BL/6 than in BALB/c. Production of nitric oxide, recently shown to be one of the antiviral effector mechanisms of macrophages, by macrophages of both strains was examined showing more production of nitric oxide on day 7 after infection in C57BL/6 than in BALB/c. From these findings, we suggest the possibility that CD4+ T-cells contribute to the protection against MCMV infection via the secretion of cytokines and the resultant activation of macrophages to produce nitric oxide.

Animals↗
PubMed1995

C-fos expression in vivo in human lymphocytes in response to stress.

1. Blood samples from which lymphocytes were isolated were obtained from patients immediately prior to cardiac catheterization (stress period) and again four to five hours later (post-stress period). Blood was also taken from a normal non-stressed control subject. 2. Lymphocyte c-fos mRNA was reverse transcribed followed by strand synthesis of DNA template and amplification using PCR with sequence-specific primers. 3. C-fos mRNA was detectable in lymphocytes from the normal control subject and in patient samples obtained immediately prior to cardiac catheterization, but was not detectable in patient samples obtained four to five hours later. 4. Possible mechanisms for these findings include a stress-related decrease in lymphocyte proliferation and differentiation or a negative feedback effect of the c-fos protein on transcription of the c-fos gene. 5. These findings suggest that it may be possible to monitor peripheral early gene expression as a marker for a variety of conditions including stress, psychiatric disorders and the response to psychotropic drugs.

DNA Probes↗
PubMed1995

Effectiveness of Norplant implants through seven years: a large-scale study in China.

The effectiveness of Norplant implants over a seven year period of continuous use was studied in a multicenter trial. Pregnancy rates were 0.4 per 100 in both year six and year seven. More than 3,600 women completed 6 years and more than 2,400 women completed 7 years. Pregnancy rates increased with weight (p < .05) and decreased with age, but in years 6 and 7 combined, the pregnancy rate neither reached nor exceeded 1 per 100 woman years in any 5 year age group or in any 10 kg weight group.

Adult↗
PubMed1995

Selective activation of VH3A10+ rheumatoid factor producing B cells by staphylococcal enterotoxin D.

Staphylococcal enterotoxin D (SED) is a T cell superantigen which selectively targets alpha beta TCRs bearing particular V beta elements. A second function of SED relates to the preferential activation of a B cell subset characterized by a high frequency of rheumatoid factor (RF) producing B cells. To define the molecular basis of the SED-induced B cell repertoire shift, we have analyzed Ig heavy chain genes in B cell clones expanded after SED stimulation and compared them with B cell clones established in the presence of anti-CD3 stimulated helper cells. Gene segments of the VH3 family were most frequently utilized under both stimulation conditions (42% anti-CD3; 47% SED). Sequence analysis of VH3 gene segments demonstrated that the repertoire of VH3 elements in B cell clones from SED driven and anti-CD3 driven cultures were distinct (P = 0.01). RF activity was closely associated with the expression of selected VH3 elements. B cell clones stimulated with SED preferentially expressed VH3A10, whereas VH26 was the gene segment dominantly used in B cell clones expanded with anti-CD3 stimulated helper cells. The usage of JH and DH elements was indistinguishable in SED and anti-CD3 driven B cell clones, suggesting that SED targets VH3+ B cells through a VH-specific mechanism. Comparison of the closely related sequences of the SED responsive VH3A10 and the SED non-responsive VH26 element suggested a role of a sequence polymorphism in the CDR2 reminiscent of B cell reactivity to conventional antigens. In contrast to conventional antigens, SED can induce differentiation of a high frequency of naive B cells. Thus, this staphylococcal enterotoxin combines selective activation of T cells with selective activation of B cells and might be able to direct T cell help to RF producing B cells.

Adult↗
PubMed1995

Torulopsis glabrata: azole susceptibilities by microdilution colorimetric and macrodilution broth assays.

Fluconazole and itraconazole MICs were determined by both the standard macrodilution method of the National Committee for Clinical Laboratory Standards and a colorimetric broth microdilution method for 140 isolates of Torulopsis (Candida) glabrata obtained over a 15-year period. Using the method of the National Committee for Clinical Laboratory Standards the MICs at which 90% of isolates are inhibited (MIC50) for all isolates were 32 and 1.6 micrograms/ml for fluconazole and itraconazole, respectively. For fluconazole, the MIC90 rose from 16 to > 64 micrograms/ml when the MIC90s for isolates collected from July 1980 to June 1991 were compared with those for isolates collected from July 1991 to March 1995. For itraconazole, the MIC90s for isolates from the same time periods were 0.8 and 3.2 micrograms/ml, respectively. Although for isolates from some non-human immunodeficiency virus-infected patients the MICs rose, most of the high MICs were found for isolates from human immunodeficiency virus-infected patients who had been extensively treated with azole drugs for thrush. The colorimetric method yielded endpoints that were more definitive; concordances within 2 dilutions for the two methods were 87% for fluconazole and 86% for itraconazole.

Antifungal Agents↗
PubMed1995

Use of a colorimetric system for yeast susceptibility testing.

We examined the reliability and accuracy of a colorimetric assay using Alamar Blue reagent in the performance of susceptibility tests for Candida albicans. We compared the broth macrodilution method recommended by the National Committee for Clinical Laboratory Standards (NCCLS) with a macrodilution method modified with the Alamar reagent and a microdilution method modified with the Alamar reagent. The MICs of fluconazole and itraconazole for 97 isolates of C. albicans and 3 control isolates were tested. For fluconazole, the Alamar-modified broth macrodilution method yielded 94% (91 of 97) concordance within 2 dilutions compared with the NCCLS method, while the microdilution method yielded 95% (92 of 97) concordance. With Alamar-modified methods for itraconazole, broth macrodilution yielded 97% (94 of 97) concordance within 2 dilutions. MICs obtained by the microdilution method, although tightly nested, were shifted to a higher value when compared with those obtained by the NCCLS method; there was only 77% (75 of 97) concordance within 2 dilutions but 97% concordance (94 of 97) within 3 dilutions. Tests by all methods with quality control strains showed excellent reproducibilities. For fluconazole, the methods modified with the Alamar reagent yielded clear endpoints and excellent correlation for the broth macrodilution and microdilution methods. For itraconazole, the methods modified with the Alamar reagent yielded clear endpoints and were reproducible, but higher MICs were obtained by the microdilution methods compared with those obtained by the NCCLS methods.

AIDS-Related Opportunistic Infections↗
PubMed1995

Induction of apoptosis of T cells by infecting mice with murine cytomegalovirus.

Cytomegalovirus (CMV) is associated with several lymphocyte dysfunctions, but the precise mechanisms of the dysfunctions are still unclear. To elucidate the mechanisms, a cell cycle-DNA content analysis was performed on splenic T cells of murine CMV (MCMV)-infected BALB/c mice. T cells from mice infected with 3 x 10(3) PFU of MCMV contained a higher percentage of hypodiploid nuclei after 12 or 24 h of culture than those from naive mice. T cells from infected mice also contained a larger amount of fragmented DNA. Taken together, these results suggested that infection with MCMV induced the apoptotic cell death of T cells. This induction of apoptosis accounted for the dysfunction of lymphocytes, at least partially. Flow cytometric analysis showed that T cells as well as B cells from MCMV-infected mice expressed an augmented level of Fas antigen, an apoptosis-associated cell surface molecule, which might be the cause of the apoptosis of cells. T cells from MCMV-infected C57BL/6-lpr/lpr mice with mutations at the lpr/fas locus, however, also showed a substantial level of apoptosis, which was reproducibly lower than that seen in C57BL/6 mice. Therefore, it was suggested that the Fas-mediated pathway contributed to but was not sufficient for the induction of apoptosis and that mechanisms other than the Fas-associated pathway were also involved in the induction of apoptosis.

Animals↗