Biomedical subjects

Z Yin

Publications and source records attributed to Z Yin.

At least 73 records · Page 4Linked to original sources

PubMed1999

Regulation of JNK signaling by GSTp.

Studies of low basal Jun N-terminal kinase (JNK) activity in non-stressed cells led us to identify a JNK inhibitor that was purified and identified as glutathione S-transferase Pi (GSTp) and was characterized as a JNK-associated protein. UV irradiation or H2O2 treatment caused GSTp oligomerization and dissociation of the GSTp-JNK complex, indicating that it is the monomeric form of GSTp that elicits JNK inhibition. Addition of purified GSTp to the Jun-JNK complex caused a dose-dependent inhibition of JNK activity. Conversely, immunodepleting GSTp from protein extracts attenuated JNK inhibition. Furthermore, JNK activity was increased in the presence of specific GSTp inhibitors and a GSTp-derived peptide. Forced expression of GSTp decreased MKK4 and JNK phosphorylation which coincided with decreased JNK activity, increased c-Jun ubiquitination and decreased c-Jun-mediated transcription. Co-transfection of MEKK1 and GSTp restored MKK4 phosphorylation but did not affect GSTp inhibition of JNK activity, suggesting that the effect of GSTp on JNK is independent of the MEKK1-MKK4 module. Mouse embryo fibroblasts from GSTp-null mice exhibited a high basal level of JNK activity that could be reduced by forced expression of GSTp cDNA. In demonstrating the relationships between GSTp expression and its association with JNK, our findings provide new insight into the regulation of stress kinases.

3T3 Cells↗

PubMed1999

Cooperative activity of alpha4beta1 and alpha4beta7 integrins in mediating human B-cell lymphoma adhesion and chemotaxis on fibronectin through recognition of multiple synergizing binding sites within the central cell-binding domain.

We have quantitated the relative contributions of the constitutively active alpha4beta1 and alpha4beta7 integrins and the domains embodying their cognate binding sites in mediating human B-cell lymphoma adhesion and chemotaxis on fibronectin. By cooperating, the central cell-binding and IIICS carboxy-terminal domains were entirely responsible for the adhesion activity displayed by fibronectin, and their relative contribution to this process was estimated to be 30% versus 70%. Assessment of the leukocyte-substrate binding strength (ie, dynes/cell) indicated a 10-fold higher avidity of the cell-IIICS domain interaction. The two integrins interchangeably recognized both domains, but differed quantitatively in their participation in the adhesive event, as well as in domain preference. The use of 3Fn (according to the nomenclature proposed by Bork and Koonin [Curr Opin Struct Biol 6:366, 1996] for the type III fibronectin modules) module-specific antibodies and recombinant polypeptides showed that alpha4 integrins recognized both the RGD sequence (3Fn10) and an apparently novel synergistic site located within the 3Fn8 module; even in this case, the integrins displayed a distinct binding site preference. Interleukin-1beta (IL-1beta)/IL-2-induced chemotaxis also involved cooperative function of the central cell-binding and IIICS domains, but the mechanisms regulating this phenomenon differed markedly from those controlling cell adhesion. First, the relative contribution of the individual domains was comparable, but neither of the individual domains promoted migration to the extent observed on intact fibronectin. Secondly, alpha4beta1 and alpha4beta7 integrins were both involved in the domain-binding necessary for initiation of migration, but the relative contribution of each receptor in the chemotactic process was less disparate than for initial cell adhesion. Thirdly, the mode by which chemotactic B-lymphoma movement was supported by the central cell-binding domain differed from that sustaining cell adhesion in that it involved independent recognition of either the 3Fn8 or the 3Fn9 module, which acted in synergy with the 3Fn10 module. Our data provide novel evidence concerning the relative importance of the constitutively active alpha4beta1 and alpha4beta7 integrins for the interaction of B-cell lymphoma cells with fibronectin, and they emphasize a multiple and diverse recognition of sites responsible for either anchorage or locomotion of tumor leukocytes on this matrix molecule.

Binding Sites↗

PubMed1999

Low secretion of tumor necrosis factor alpha, but no other Th1 or Th2 cytokines, by peripheral blood mononuclear cells correlates with chronicity in reactive arthritis.

OBJECTIVE: To determine Th1 and Th2 cytokine production in patients with reactive arthritis (ReA) in relation to disease outcome and in comparison with rheumatoid arthritis (RA). METHODS: Secretion of tumor necrosis factor alpha (TNFalpha), interferon-gamma, interleukin-10 (IL-10), and IL-4 by peripheral blood mononuclear cells (PBMC) from 53 patients with early ReA (disease duration <8 weeks, 64% HLA-B27 positive) and 30 patients with early, untreated RA (disease duration <6 months) was determined by enzyme-linked immunosorbent assay (ELISA) after ex vivo stimulation. Intracellular cytokine staining with quantification of positive T cells by fluorescence-activated cell sorting (FACS) was performed in 12 ReA patients and 12 RA patients. In 27 ReA patients, cytokine secretion was measured again after 3 months. Patients were followed up for 1 year, and cytokine patterns were correlated with disease duration. RESULTS: TNFalpha secreted by whole PBMC and by T cells was significantly lower, by ELISA and by FACS, in ReA patients than in RA patients, while no significant differences were detected for the other cytokines. ReA patients with a disease duration of > or =6 months showed significantly lower TNFalpha secretion than patients with a disease duration of <6 months (mean +/- SD 385 +/- 207 pg/ml versus 684 +/- 277 pg/ml; P = 0.003). Furthermore, low TNFalpha secretion after 3 months also correlated significantly with a more chronic course of disease. HLA-B27 positive patients secreted less TNFalpha than did those who were B27 negative (338 +/- 214 pg/ml versus 512 +/- 207 pg/ml; P = 0.05), and patients with a more chronic course had a higher frequency of B27 positivity (47% versus 80%; P = 0.01). Among the 27 HLA-B27 positive patients, TNFalpha secretion in those with a disease duration of > or = 6 months was lower than that in the 7 with a disease duration of <6 months (308 +/- 167 pg/ml versus 562 +/- 308 pg/ml; P = 0.04). CONCLUSION: Low TNFalpha secretion and HLA-B27 status correlate with longer disease duration in ReA patients, possibly with an additive effect. The diminished TNFalpha production might reflect a state of relative immunodeficiency contributing to bacterial persistence in ReA.

Adult↗

PubMed1999

Identification of differentially expressed genes in Con A-activated carp (Cyprinus carpio L.) leucocytes.

A cDNA library was constructed from the message RNA (mRNA) obtained from Con A-induced head kidney (HK) leucocytes of carp (Cyprinus carpio L.). Differential screening of the cDNA was carried out by hybridization against the total cDNA probes from normal, Con A-uninduced HK leucocytes or Con A-induced HK leucocytes of carp. The differential expression patterns of certain cDNA clones were confirmed by Southern-blot and Northern-blot analysis. Single-pass of the sequencing analysis and homology search in Genbank (EMBL) revealed those differentially expressed cDNA clones encode for cytochrome c oxidase sub-unit II and III (COII and COIII), elongation factor-1 beta (EF-1 beta), bleomycin hydrolase (BH), heat shock cognate protein 70 (HSC70) and 16S ribosomal RNA (16S rRNA).

Amino Acid Sequence↗

PubMed1999

Dispositional and situational goal orientations as discriminators among recreational and competitive league athletes.

The present study examined the relationship between individual goal orientation, motivational team climate, perceived sport competence, and league structure among 216 youth soccer players. It was predicted that competitive league teams would report higher ego-involvement and performance-oriented team climate and lower sport competence than recreational teams. Discriminant analyses indicated that only the mastery-oriented team climate variable differentiated competitive and recreational teams. Athletes who participated in recreational teams reported a greater degree of mastery-oriented climate than competitive league players. The results suggest that athletes' perceptions of situational rather than dispositional aspects of achievement goals are more highly affected by the playing structure present in youth sport teams. The possible psychological benefits derived from the development of a mastery-oriented team climate in sports are discussed.

Adolescent↗

PubMed1999

The elevated ratio of interferon gamma-/interleukin-4-positive T cells found in synovial fluid and synovial membrane of rheumatoid arthritis patients can be changed by interleukin-4 but not by interleukin-10 or transforming growth factor beta.

OBJECTIVES: To quantify the T-helper type (Th) 1 cytokine interferon gamma (IFN-gamma)-positive and the Th2 cytokine interleukin (IL)-4-positive cells in synovial fluid (SF) and synovial membrane (SM) at the single-cell level in rheumatoid arthritis (RA) in comparison to reactive arthritis (ReA), and to manipulate the cytokine pattern of RA patients in vitro. METHODS: Eighteen patients with RA and 17 with ReA were studied. For intracellular staining of cytokines, SF mononuclear cells (MNC) from seven patients with RA, in comparison to eight patients with ReA, were triple stained with anti-IFN-gamma, IL-4 and anti-CD4 or anti-CD8 monoclonal antibodies (mAb) and analysed by flow cytometry. Furthermore, in 13 patients with RA, immunohistology of SM was performed and compared with seven ReA patients. In addition, in six of the RA patients, synovial T cells were grown over 3 weeks in the presence of various cytokines and intracellular cytokine staining analysed by flow cytometry weekly. RESULTS: In SF, the mean percentage of IFN-gamma+/CD4+ T cells in RA was almost 4-fold higher than the number of IL-4+/CD4+ T cells (11.3+/-5 vs 3.02+/-1.04; P=0.0012), while the ratio of IFN-gamma/IL-4+ CD4+ T cells was only 1.59 in ReA (P=0.047 for the ratio difference). A similar result was obtained for SM: the ratio of IFN-gamma/IL-4+ cells in RA was 4.3 (P<0.0001 for the IFN-gamma/IL-4 difference), but only 1.2 for ReA (P=0.02 for the ratio difference). Of the CD3+ cells in SM, 2.8% were positive for IFN-gamma and 0.4% for IL-4 in three RA patients. A decrease in the number of IFN-gamma-positive SF T cells and an increase in the number of IL-4-positive SF T cells could be achieved in vitro through IL-4, but not by IL-10 or transforming growth factor beta. CONCLUSIONS: The Th1 pattern in the joint of RA patients demonstrated at the single-cell level may be important for the pathogenesis of RA and may provide a target for future immunotherapy. Our data suggest a therapeutic role for IL-4.

Adolescent↗

PubMed1999

Perceived competence, social anxiety about physique, and enjoyment in testing situations among groups of mixed sex and girls only.

The purpose of the present study was to assess whether there are differences in agility and coordination performance, anxiety about physique, perceived competence, and enjoyment between girls (n = 56) performing within mixed-sex versus all-female high school classes in physical education. A series of between-group comparisons yielded no significant differences between groups on measures of performance, perceived competence, and anxiety about physique; however, the mixed-sex group reported significantly greater enjoyment on both psychomotor tests than the all-female group (ps < or = .05). Results are discussed within other contexts such as sport motivation and Weiss and Chaumeton's (1992) theory of youth sport development.

Adolescent↗

PubMed1999

[Evaluation of effectiveness of hepatitis B plasma derived vaccine and a survey of hepatitis C virus infection in preschool children in Chengdu, Sichuan].

This study was undertaken to evaluate the effectiveness of hepatitis B plasma-derived vaccine and investigate the character of hepatitis C virus infection in preschool children. The anti-HBs, HBsAg and anti-HCV of 985 plasma samples were examined by ELISA. The results showed that the positive rate of HBsAg in the children (aged < 7 yr) in the communities was 0.89% and the effectiveness of the vaccine was 91.38%. The positive rate of anti-HBs decreased with the increase in age; the positive rate of HBsAg did not increase with age. The positive rate of HBsAg was as high as 4.69% in the children from hospitals, so supervision and enhanced vaccination should be administered properly in this group. The positiverate of anti-HCV was 1.18% in the communities, but 3.17% in hospitals. It is worthy to investigate how children get infected with HCV.

Child, Preschool↗

PubMed1999

[Cytological diagnosis of Hashimoto's hyperthyroidism].

OBJECTIVE: To assess the value of thyroid fine needle biopsy (FNB) in Hashimoto's hyperthyroidism. METHODS: FNB for was performed 58 (5 males and 53 females, aged from 13 to 66 years) of 1 031 patients who was performed clinically dignosised as having hyperthyroidism according to clinic symptoms, the results of physical and, laboratory examination, especially the increased the serum circle antibody and lowered sTSH during March 1995 to February 1998. Their smears were classified into 4 types according to the degree of degeneration of adenoidal cell and lymphocyte invasion. RESULTS: Hyperthyroidism was observed in 5 cases, I type in 9, II type in 9, III type in 4, and IV type in 31 (53%). CONCLUSIONS: FNB is helpful in diagnosis of hyperthyroidism.

Adolescent↗

PubMed1999

[Effect of Boschniakia rossica extract on antioxidative activities in rat hepatic preneoplasia induced by diethylnitrosamine].

OBJECTIVE: To study the antioxidative effect of aqueous fraction of Boschniakia rossica(BR) extracted with methanol and fractionated with dichloromethane and water. METHOD: Serum activities of superoxide dismutase(SOD), malondialdehyde(MDA), glutathione peroxidase (GSH-PX) and glutathione S-transferase (GST) were investigated in rat with preneoplasia induced by Solt-Farber protocol under administration with BR extract for 6 weeks. RESULT: Serum activities of SOD and GSH-PX rose again in rats administered with BR extract, and the increase of GST activity and content of MDA due to hepatic preneoplasia was decreased by the extract of BR, thus the pathological changes of tissues and cells can be reduced. CONCLUSION: BR extract has antioxidative effect which may be a part of the antitumor mechanism of B. rossica.

Animals↗

PubMed1999

[The development of mouse bioreactor expressing human tissue plasminogen activator (tPA) in mammary gland by transfecting spermatozoa in testicular duct].

The most established methods for development of transgenic animals are the microinjection of DNA into the fertilized eggs, but it is still a procedure of certain complexity and high cost. Therefore, the idea of using sperm as a vehicle to carry exogenous DNA into eggs is very attractive, and there have been some successful reports. Though the methods are rather simple they sometimes have low reproducibility. To improve the technique we transinfected the spermatozoa in testicular duct, not in vitro, to produce mice which expressed human tissue plasminogen activator (tPA) in mammary gland. The results demonstrated that: (1) 5 transinfected mice mated 10 female mice in 10 days after operation, (2) 79 founders were developed and 42 survived, (3) using PCR to detect foreign DNA integrated into the genome of founders, 7 out of 42 founders were positive (16.67%), (4) The expression level of tPA was 48-80 ng/ml in the milk of 5 PCR positive founders and (5) the foreign DNA integrated into the genome was detected in 2 out of 4 1st offspring by PCR technique.

Animals↗

PubMed1999

[Molecular clone and sequence analysis of cDNA fragments of hog cholera virus strain C].

The 5' nonencoding region, p23 and p14 encoding region and E1 gene of hog cholera virus (HCV) strain C were amplified from total RNA extracted from HCV strain C infected rabbit spleen by reverse transcription and nested or half--nested PCR. The PCR products were cloned into pGEM-T vector. Nucleotide sequencing was performed using an ABI PRISM sequencing device; based on the incorporation of fluoresect labelled dideoxynuclotide teminators. The obtained sequences on 5' noncoding region and part of p23 and p14 encoding region were compared with HCV strains Shimen and C sequenced in Moormann's lab. The result showed that the homology between HCV strains C sequenced in this report and in Moormann's lab was 99.19%, and the homology between HCV strains Shimen, the standard virulent HCV strain in China, and C sequenced in this report was 94.69%. It was also discovered that the base C at 244 of the genome of HCV strains Shimen and C sequenced in this report was absent at the genome of C strain sequenced in Moormann's lab et al.

5' Untranslated Regions↗

PubMed1999

[The problems and solutions of the leakage current checking in medical electrical equipments].

It is an important safety checking item to check leakage current of medical electric equipments. In the national standard, there are definite and strict stipulations for the leakage current-checking and the checkers. But this important checking is often misrepresented with general current measurements. So the checking is not up to the standard and the results are not dependable. In this paper, the special demands for the checking and the key technique of the checkers have been expounded in detail.

Electricity↗

PubMed1998

JNK targets p53 ubiquitination and degradation in nonstressed cells.

In this study we elucidated the role of nonactive JNK in regulating p53 stability. The amount of p53-JNK complex was inversely correlated with p53 level. A peptide corresponding to the JNK binding site on p53 efficiently blocked ubiquitination of p53. Similarly, p53 lacking the JNK binding site exhibits a longer half-life than p53(wt). Outcompeting JNK association with p53 increased the level of p53, whereas overexpression of a phosphorylation mutant form of JNK inhibited p53 accumulation. JNK-p53 and Mdm2-p53 complexes were preferentially found in G0/G1 and S/G2M phases of the cell cycle, respectively. Altogether, these data indicate that JNK is an Mdm2-independent regulator of p53 stability in nonstressed cells.

3T3 Cells↗

PubMed1998

Smad proteins act in combination with synergistic and antagonistic regulators to target Dpp responses to the Drosophila mesoderm.

Dorsal mesoderm induction in arthropods and ventral mesoderm induction in vertebrates are closely related processes that involve signals of the BMP family. In Drosophila, induction of visceral mesoderm, dorsal muscles, and the heart by Dpp is, at least in part, effected through the transcriptional activation and function of the homeobox gene tinman in dorsal mesodermal cells during early embryogenesis. Here we present a functional dissection of a tinman enhancer that mediates the Dpp response. We provide evidence that mesoderm-specific induction of tinman requires the binding of both activators and repressors. Screens for binding factors yielded Tinman itself and the Smad4 homolog Medea. We show that the binding and synergistic activities of Smad and Tinman proteins are critical for mesodermal tinman induction, whereas repressor binding sites prevent induction in the dorsal ectoderm and amnioserosa. Thus, integration of positive and negative regulators on enhancers of target genes appears to be an important mechanism in tissue-specific induction by TGF-beta molecules.

Amino Acid Sequence↗

PubMed1998

Regulation and function of tinman during dorsal mesoderm induction and heart specification in Drosophila.

The homeobox gene tinman plays a key role in the specification of Drosophila heart progenitors and the visceral mesoderm of the midgut, both of which arise at defined positions within dorsal areas of the mesoderm. Here, we show that in addition to the heart and midgut visceral mesoderm, tinman is also required for the specification of all dorsal body wall muscles. Thus it appears that the precursors of the heart, visceral musculature, and dorsal somatic muscles are all specified within the same broad domain of dorsal mesodermal tinman expression. Locally restricted activities of tinman are also observed during its early, general mesodermal expression, where tinman is required for the activation of the homeobox gene buttonless in precursors of the "dorsal median" (DM) glial cells along the ventral midline. These observations, together with others showing only mild effects of ectopic tinman expression on heart development, indicate that tinman function is obligatory, but not sufficient to determine individual tissues within the mesoderm. Therefore, we propose that tinman has a role in integrating positional information that is provided by intersecting domains of additional regulators and signals, which may include Wingless, Sloppy Paired, and Hedgehog in the dorsal mesoderm and EGF-signaling at the ventral midline. Previous studies have shown that Dpp acts as an inductive signal from dorsal ectodermal cells to induce tinman expression in the dorsal mesoderm, which, in turn, is needed for heart and visceral mesoderm formation. In the present report, we show that Thickveins, a type I receptor of Dpp, is essential for the transmission of Dpp signals into the mesoderm. Constitutive activity of Tkv in the entire mesoderm induces ectopic tinman expression in the ventral mesoderm, and this results in the ectopic formation of heart precursors in a defined area of the ventrolateral mesoderm. We further show that Screw, a second BMP2/4-related gene product, Tolloid, a BMP1-related protein, and the zinc finger-containing protein Schnurri, are required to allow full levels of tinman induction during this process. It is likely that some of these functional and regulatory properties of tinman are shared by tinman-related genes from vertebrates that have similarly important roles in embryonic heart development.

Animals↗

PubMed1998

Characterization of the synovial T cell response to various recombinant Yersinia antigens in Yersinia enterocolitica-triggered reactive arthritis. Heat-shock protein 60 drives a major immune response.

OBJECTIVE: In Yersinia enterocolitica-triggered reactive arthritis (Yersinia ReA), the synovial T cell response is primarily directed against bacterial components, which are mostly unknown. This study was performed to investigate the synovial proliferative T cell response to a panel of recombinant Yersinia antigens in patients with Yersinia ReA and in controls. METHODS: Synovial fluid mononuclear cells (SFMC) were obtained from 4 patients with Yersinia ReA and from 14 patients with arthritides of different etiology. SFMC were stimulated with 5 recombinant Yersinia antigens (the 19-kd urease beta subunit, 13-kd ribosomal L23 protein, 32-kd ribosomal L2 protein, 18-kd outer membrane protein H, and Y. enterocolitica heat-shock protein 60 [hsp60]), and with human, Chlamydia trachomatis, and Borrelia burgdorferi hsp60. Three T cell clones specific for Y. enterocolitica hsp60 were generated from 1 patient with Yersinia ReA. Antigen-induced cytokine release was measured by enzyme-linked immunosorbent assay. RESULTS: SFMC from all 4 patients with Yersinia ReA responded to each of the Yersinia antigens except the 13-kd protein. These antigens were also recognized by SFMC from a subgroup of patients with undifferentiated arthritis (n = 4), but not by SFMC from other patients with arthritis of different etiology (n = 10). Y. enterocolitica hsp60 induced the strongest proliferative response in all cases. Two types of hsp60-reactive T cell clones could be obtained. One clone responded to all hsp60 variants, including the human variant, and showed a type 2 T helper (Th2)-like cytokine-secretion pattern. In contrast, another clone with specificity for the bacterial hsp60 proteins, but not the human equivalent, reacted with a more Th1-like pattern. CONCLUSION: In Y. enterocolitica-triggered ReA, at least 4 immunodominant T cell antigens exist, which might be used in lymphocyte proliferation assays to identify patients with Yersinia ReA. The hsp60 is a strong antigen, inducing both bacteria-specific and potentially autoreactive CD4+ T cells of both the Th1 and Th2 type.

Adolescent↗

PubMed1998

Modulating the Th1/Th2 balance in inflammatory arthritis.

The balance between Th1 and Th2 cells regulates the choice between inflammatory and antibody-mediated immune responses. To an increasing extent this balance is thought to involve the participation of antigen-presenting cells, rather than the entirely autonomous activity of T cells and their cytokines. Here we survey current opinion concerning the working of this balance, and its condition in rheumatoid arthritis and the other inflammatory arthritides. The contrast between Lyme arthritis and reactive arthritis is particularly illuminating, since one is triggered by extracellular and the other by intracellular infection. We describe current approaches to the modulation of this balance. Guided by the principles that genetic polymorphism is likely to identify relevant genes, that any cytokine gene picked up by a virus must matter and that natural immunosuppressive activity at mucosal surfaces should be worth exploiting, we identify as particularly worthy of attention: (i) IL-10, (ii) inhibitors of IL-12 production, (iii) inhibitors of CD40 ligand expression and (iv) oral and nasal tolerance. Other protective T cell subsets are touched on, and the impact of oligonucleotide arrays mentioned.

Animals↗