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Biomedical subjects

R Jin

Publications and source records attributed to R Jin.

At least 37 records · Page 2Linked to original sources
PubMed2001

Prostaglandin E1 protects lung transplants from ischemia-reperfusion injury: a shift from pro- to anti-inflammatory cytokines.

INTRODUCTION: Prostaglandin E1 (PGE1) has been demonstrated to reduce ischemia-reperfusion (IR) injury following lung transplantation. However, the cytoprotective mechanisms remain largely unknown. The purpose of this study was to determine whether the mechanism through which PGE1 improves IR injury is related to the level of apoptosis or the release of inflammatory cytokines. METHODS: In a rat single-lung-transplant model, animals were randomly allocated into four groups of five animals each. Group 1 received normal saline (NS) in the preservation solution and during the 2-hr reperfusion period. Group 2 received NS in the preservation solution and PGE1 during the reperfusion period. Group 3 received PGE1 in the preservation solution and NS during the reperfusion period. Group 4 received PGE1 in the preservation solution and during the reperfusion period. RESULTS: The two groups that received PGE1 during the reperfusion period had a significantly higher partial pressure of oxygen (PaO2), lower wet-dry weight ratio, and lower peak airway pressure at the end of the reperfusion period than did the two groups that received NS. In the two groups that received PGE1 during the reperfusion period, we observed significantly higher levels of interleukin (IL)-10 in the transplanted lung tissue and plasma and significantly lower levels of tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, and IL-12 in lung tissue. The levels of IL-4 and macrophage inflammatory protein-2 (MIP-2) were not significantly different between groups. The number of apoptotic cells and the expression of Bcl-2 were not significantly different between groups. CONCLUSIONS: PGE1 does not decrease the amount of apoptosis after reperfusion and does not significantly upregulate Bcl-2. We have demonstrated that PGE1 administered during the reperfusion period reduces IR injury and improves lung function through a mechanism that is likely mediated by a shift between pro- and anti-inflammatory cytokine release.

Alprostadil↗
PubMed2001

Observation of Andreev surface bound states in the 3-K phase region of Sr2RuO4.

The tunneling spectrum of the superconducting phase with Tc approximately 3.0 K has been measured in the Ru-embedded region of Sr2RuO4 using cleaved junctions. A sharp zero-bias conductance peak (ZBCP) has been observed below 3 K. All characteristics of this ZBCP suggest that it originates from Andreev surface bound states, indicating that the pairing in the 3-K phase is also non- s-wave. Below the bulk Tc of Sr2RuO4 (approximately 1.5 K), a crossover from sharp to bell-shaped ZBCP was found. This supports the theory that there is a phase transition in the 3-K phase region near the bulk Tc.

Journal Article↗
PubMed2001

Non-Fermi-liquid behaviour in La4Ru6O19.

Understanding the complexities of electronic and magnetic ground states in solids is one of the main goals of solid-state physics. Transition-metal oxides have proved to be particularly fruitful in this regard, especially for those materials with the perovskite structure, where the special characteristics of transition-metal-oxygen orbital hybridization determine their properties. Ruthenates have recently emerged as an important family of perovskites because of the unexpected evolution from high-temperature ferromagnetism in SrRuO3 to low-temperature superconductivity in Sr2RuO4 (refs 1, 2). Here we show that a ruthenate in a different structural family, La4Ru6O19, displays a number of highly unusual properties, most notably non-Fermi-liquid behaviour. The properties of La4Ru6O19 have no analogy among the thousands of previously characterized transition-metal oxides. Instead, they resemble those of CeCu6-xAux-a widely studied f-electron-based heavy fermion intermetallic compound that is often considered as providing the best example of non-Fermi-liquid behaviour. In the ruthenate, non-Fermi-liquid behaviour appears to arise from just the right balance between the interactions of localized electronic states derived from Ru-Ru bonding and delocalized states derived from Ru-O hybridization.

Journal Article↗
PubMed2001

ISMh2, a novel insertion sequence-like element associated with nifA from Mesorhizobium huakuii.

Sequence analysis of the nifA gene, including its 5' flanking region, of Mesorhizobium huakuii revealed the presence of a novel IS-like element called ISMh2. It is 828 bp in length and possesses two imperfect terminal inverted repeats of 14 bp with only one mismatch. The putative transposase encoded by ISMh2 is composed of 204 amino acids. In comparison with other insertion sequences ISMh2 likely belongs to the IS6 family. Multiple copies of ISMh2 were detected in the genome of M. huakuii 159 by Southern hybridization. RT-PCR analysis showed that nifA and ISMh2 cotranscribed. Attempts to detect the transposition ability of ISMh2 were unsuccessful.

Alphaproteobacteria↗
PubMed2001

Role of the double-strand origin cruciform in pT181 replication.

pT181 is a small rolling-circle plasmid from Staphylococcus aureus whose initiator protein, RepC, melts the plasmid's double-strand origin (DSO) and extrudes a cruciform involving IR II, a palindrome flanking the initiation nick site. We have hypothesized that the cruciform is required for initiation, providing a single-stranded region for the assembly of the replisome (R. Jin et al., 1997, EMBO J. 16, 4456-4566). In this study, we have tested the requirement for cruciform extrusion by disrupting the symmetry of the IR II palindrome or by increasing its length. The modified DSOs were tested for replication with RepC in trans. Rather surprisingly, disruption of the IR II symmetry had no detectable effect on replication or on competitivity of the modified DSO, though plasmids with IR II disrupted were less efficiently relaxed than the wild type by RepC. However, in conjunction with IR II disruption, modification of the tight RepC binding site IR III blocked replication. These results define two key elements of the pT181 initiation mechanism--the IR II conformation and the RepC binding site (IR III)--and they indicate that pT181 replication initiation is sufficiently robust to be able to compensate for significant modifications in the configuration of the DSO.

Bacterial Proteins↗
PubMed2001

Significance of metallothionein expression in breast myoepithelial cells.

Metallothioneins (MTs), a group of cysteine-rich proteins with a small molecular mass, are known to have metalloregulatory functions. MT gene expression has been demonstrated to be cell type-specific and differentially regulated (possibly related to their germ layer origin and different functional states). In vitro studies suggest that MT-2A, MT-IE, and MT-1F isoforms may be related to breast cancer. In this study, data on MT-2A, MT-1E, MT-1F mRNA analysis via reverse transcription-polymerase chain reaction in invasive ductal breast cancer tissues and their adjacent benign breast tissues from 27 mastectomies are presented. Expression of mRNA in all the three MT isoforms was detected in both cancerous and adjacent benign breast tissues (with MT-2A mRNA expression being the highest). MT-1F expression was significantly higher in benign breast tissues compared with the breast cancers (P=0.017). In situ hybridization confirmed the expression of MT-2A mRNA in the myoepithelial cells of the breast tissues. Immunohistochemical localization of the MT protein revealed that myoepithelial cells consistently expressed the MT protein, while the cancer cells expressed MT with great variation. Based on our immunohistochemical and mRNA analysis, it is likely that the three MT isoforms are specifically expressed in myoepithelial cells of benign breast tissues and cancer cells of the invasive ductal breast cancer tissues. As MT expression occurs in myoepithelial cells and ductal breast cancer cells, our finding supports the proposition that loss of myoepithelial cells in invasive mammary cancers may be compensated in part by changes in the tumor cells, which may subsequently be the basis for studying the role of MT in breast physiology and carcinogenesis. Differential MT-1F expression in breast myoepithelial cells warrants further study.

Breast↗
PubMed2001

Receiver operating characteristic curve analysis of clinical risk models.

Receiver operating characteristic (ROC) curve analysis is a useful method to measure the ability of a clinical risk model to discriminate between hospital deaths and survivors. Its use in medicine originated as a method for synthesizing the specificity and sensitivity of diagnostic tests across a spectrum of possible cut points. The area under the ROC curve can be interpreted as a probability of correct classification or prediction. We illustrate its use in three steps: first, with a dichotomous variable to introduce specificity and sensitivity; next, with a categorical risk factor (surgical urgency) to produce a primitive ROC curve; and finally, with a continuous risk factor (age) to approximate the usual ROC curve used for clinical risk models.

Adult↗
PubMed2001

Metallothionein 1F mRNA expression correlates with histological grade in breast carcinoma.

Immunohistochemical expression of metallothioneins (MTs), a group of intracellular metal-binding proteins, is well documented in breast cancer. However, there is a paucity of information on the expression of the different MT isoforms in breast cancer tissues. The dichotomous association of MT overexpression with tumour types and progression led us to examine the role of the MT-1F mRNA isoform in breast cancer. We evaluated MT expression in 48 primary invasive ductal breast cancer tissues by immunohistochemistry, and the corresponding MT-1F mRNA expression via a semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay. The specificity of the RT-PCR products was confirmed by direct cycle sequencing and restriction enzyme digestion. Immunohistochemical analysis of MT revealed a significantly higher MT expression in histological grade 3 tumours as compared to grade 1 and 2 tumours (p = 0.021). Similarly, MT-1F mRNA expression was found to be significantly higher in grade 3 tumours (p < 0.001). The results suggest that the MT-1F isoform influences histological differentiation in invasive ductal breast cancer. The converse is also true in that the histological grade may determine the level of MT-1F expression in breast cancer.

Adult↗
PubMed2001

[Significance of detection of transfusion transmitted virus in extrahepatic tissues].

OBJECTIVE: To investigate the location and distribution of transfusion transmitted virus (TTV) in the liver and extrahepatic tissues. METHODS: TTV DNA was detected in paraffin-embedded autopsy liver and extrahepatic tissues, including liver, pancreas, kidney, spleen, testicle, and heart from 13 patients with non A-G hepatitis by nested-PCR and in situ hybridization (ISH) techniques. RESULTS: Positive hybridization signals of TTV nucleus acid were observed in 5 liver, 3 kidney, 2 pancreas and spleen tissues, respectively. TTV DNA was detected in one from each two samples of testicle and heart. Positive signal was mainly located in nucleoli of the liver and extrahepatic parenchymal cells. There was not obvious pathological damage in those extrahepatic tissues. The positive rate of PCR approximately corresponded to ISH. CONCLUSIONS: TTV can infect hepatic and extrahepatic tissues and its infection in extrahepatic tissues might be responsible for a state of reinfection and higher prevalence in different population.

Adult↗
PubMed2001

[Study on the effects of increased iodized salt intake on the incidence of thyroid diseases].

OBJECTIVE: To study the annual incidence of thyroid diseases before and after the increase of iodized salt intake. METHOD: A total of 26,010 persons were examined from mid August to the end of December in 1999. RESULTS: 1. Three hundred and ten patients of thyroid diseases were identified from 1990 to July 1999. One hundred and eighty-three patients were diagnosed after iodine supplementation. 2. The constitution of thyroid diseases had changed significantly regarding the increase of hyperthyroidism, simple goiter and thyroid nodule. 3. Fifty-five patients with hyperthyroidism including 39 patients (70.91%) receiving iodine supplementation were diagnosed. The average annual incidence of hyperthyroidism after iodine supplementation was 36.87 per 100,000, a three-time increase as compared with that before iodine supplementation. The incidence of hyperthyroidism began to show a significant rise in 1996. The year with highest annual incidence was 1997, remaining at high level after supplying iodized salt. Since then the annual relative risk for hyperthyroidism had been increasing. CONCLUSION: The number of patients with thyroid diseases showed a significant increase after mass iodine supplement. At the same time, the spectrum of thyroid diseases had also changed. Iodized salt intake and the incidence of hyperthyroidism showed a significant correlation. However, the typical model of the change of disease patterns incidence needs further study.

Adult↗
PubMed2001

[Experimental and clinical studies of recombinant human growth hormone treatement of hypoproteinemia of liver cirrhosis patients].

BACKGROUND: To assess the effect of recombinant human growth hormone (rhGH) therapy to liver cirrhosis patients with hypoproteinemia. METHODS: 31 liver cirrhosis patients were treated with rh GH (0.25 IU/kg/day-) and 20 such patients with human albumin (10 g/day) as control all for 10 days. Serum levels of growth hormone (GH), insulin-like growth factor (IGF)-1 and albumin (ALB) were measured by radio-immunoassay before 24h and after 24h and 10 days of rhGH therapy. Serum levels of GH and IGF-1 of 10 age matched healthy subjects were also measured. RESULTS: As compared with healthy subjects, the pretreatment serum GH level of liver cirrhosis patients was high (4.96 +/- 3.97 vs 1.62 +/- 2.26, P <0.05), and the IGF-1 level was markedly lower (36.53 +/- 12.77 vs 56.95 +/- 16.46, P <0.01). After 10 days of rhGH administration, the serum IGF-1 and ALB levels of the treated group increased significantly as compared with the control group (P <0.01). CONCLUSIONS: Exogenous rhGH therapy can overcome the GH resistance of liver cirrhosis patient s and can increase significantly the serum albumin level as compared with the control group who were treated with human albumin only.

Female↗
PubMed2000

Immunosuppressive activity of the Chinese medicinal plant Tripterygium wilfordii. I. Prolongation of rat cardiac and renal allograft survival by the PG27 extract and immunosuppressive synergy in combination therapy with cyclosporine.

BACKGROUND: PG27 is an immunosuppressive fraction purified from an extract of a Chinese medicinal plant, Tripterygium wilfordii. We tested PG27 in rat cardiac and renal allotransplantation, and we examined the immunosuppressive interaction with cyclosporine (CsA). METHODS: Brown Norway (BN) rat heart or kidney allografts were transplanted into the abdomen of Lewis rats, which were treated by the intraperitoneal or oral route with PG27, CsA, or both. RESULTS: PG27 administered intraperitoneally to Lewis recipients for 16 days at 10-30 mg/kg/day significantly increased the median survival time of BN heart allografts from 7 to 18-22 days. Oral administration was effective, with cardiac allograft survival prolonged to > 100 days with 52 days of treatment. PG27 at 20-30 mg/kg/day significantly extended the median survival time of BN kidney allograft recipients from 9 to 36.5-77 days, and 30 mg/kg/day for 52 days extended survival beyond 200 days. PG27 combined with CsA significantly enhanced heart and kidney allograft survival, even at doses of CsA ineffective when administered alone. The addition of 5 or 10 mg/kg/day PG27 reduced by 50-75% the CsA dose needed for 100% kidney allograft survival. The combination index was less than 1.0, indicating synergy of PG27 with CsA in prolonging cardiac and renal allograft survival. Furthermore, the PG27/CsA combination exerted a positive influence on renal allograft function. PG490 (triptolide, a constituent of PG27) and PG490-88 (a semisynthetic derivative of PG490) suppressed rejection of cardiac and renal allografts. CONCLUSIONS: The PG27 herbal extract demonstrated immunosuppressive activity by prolonging heart and kidney allograft survival, displaying synergy in the immunosuppressive interaction with CsA, and improving renal allograft function in combination with CsA. PG490 and PG490-88 compounds were also effective.

Animals↗
PubMed2000

Immunosuppressive activity of the Chinese medicinal plant Tripterygium wilfordii. II. Prolongation of hamster-to-rat cardiac xenograft survival by combination therapy with the PG27 extract and cyclosporine.

BACKGROUND: PG27 is an immunosuppressive fraction purified from an extract of a Chinese medicinal plant Tripterygium wilfordii, which we investigated alone and in combination with cyclosporine (CsA) in a concordant, hamster-to-rat cardiac xenotransplantation model. METHODS: Golden Syrian hamster hearts were heterotopically transplanted into the abdomen of Lewis rat recipients, which were treated intraperitoneally or orally with PG27, CsA, or both. RESULTS: Combination therapy with 30 mg/kg(day of PG27 and CsA at 10 mg/kg/day successfully suppressed acute hamster-to-rat cardiac xenograft rejection. Treatment with PG27 or CsA alone was ineffective. Among several effective combinations, the best regimen involved PG27 at 30 mg/kg/day and CsA at 5 mg/ kg/day from days 8 to 35 and then CsA at 5 mg/kg/day from days 36 to 100, which produced 100% survival beyond 100 days. CsA suppressed the heterospecific lymphocytotoxic antibody response and inhibited IgG but not IgM xenoantibody production (which led to xenograft rejection), whereas PG27 alone did not prevent antibody production. The PG27/CsA combination blocked the lymphocytotoxic antibody response and IgG and IgM xenoantibody production induced by cardiac xenotransplantation. CONCLUSIONS: PG27 combined with CsA substantially prolonged hamster-to-rat cardiac xenograft survival, as well as completely inhibiting xenoantibody production.

Animals↗
PubMed2000

Metallothionein 1E mRNA is highly expressed in oestrogen receptor-negative human invasive ductal breast cancer.

Metallothioneins (MTs), a group of ubiquitous metalloproteins, comprise isoforms encoded by ten functional genes in humans. Different MT isoforms possibly play different functional roles during development or under various physiological conditions. The MT-1E isoform mRNA has been recently shown to be differentially expressed in oestrogen receptor (OR)-positive and OR-negative breast cancer cell lines. In this study, we evaluated MT-1E mRNA expression via semi-quantitative RT-PCR in 51 primary invasive ductal breast cancer tissues, concurrently with OR-positive and progesterone receptor (PR)-positive MCF7 cells, OR-negative and PR-negative MDA-MB-231 cells and PR-transfected MDA-MB-231 breast cancer cells (ABC28). We demonstrated significantly higher MT-1E mRNA expression in OR-negative compared with OR-positive breast cancer tissues (P = 0.026). MCF7 cells lacked MT-1E mRNA expression, while both OR- and PR-negative MDA-MD-231 cells exhibited a high level of MT-1E mRNA expression. The level of MT-1E mRNA expression in progesterone-treated and -untreated ABC28 cells remained similar as the parental cell line MDA-MB-231-C2 cells. The results suggest that MT-1E may have specific and functional roles in OR-negative invasive ductal breast cancers, possibly mediated via effector genes downstream of the oestrogen receptor, but not through the PR pathway.

Biomarkers, Tumor↗
PubMed2000

Immune regulatory effects of central nervous system antigens in culture.

Evidence from several different experimental systems suggests that regulatory cells specific for self-antigens exist in the normal immune repertoire, and that these cells are necessary for maintenance of self-tolerance and prevention of autoimmune disease. We attempted to demonstrate the existence of regulatory cells specific for central nervous system (CNS) antigens in normal mice. We tested the effects of myelin basic protein (MBP), glial fibrillary acidic protein (GFAP) and a mixture of soluble brain proteins (SBP) on cultured splenocytes. MBP at 50 microg/ml inhibited antigen-driven proliferation and this suppressive effect could be partially blocked by neutralizing antibodies to transforming growth factor (TGF)-beta. MBP decreased expression of mRNA for the cytokines IL-2 and IFN-gamma, and slightly increased mRNA expression for TGF-beta. These effects did not appear to be mediated by regulatory cells specific for MBP, since MBP also suppressed proliferation in MBP-deficient shiverer mice and the suppressive effect could not be reproduced with selected MBP peptides. SBP at 250 microg/ml also inhibited antigen-driven proliferation, but this effect could not be blocked by neutralizing antibodies against IL-4, IL-10 or TGF-beta. SBP reduced expression of mRNA for IL-2, IL-10 and TGF-beta. These results are more consistent with the presence of a soluble inhibitory factor than with the action of SBP-specific regulatory cells. GFAP had no significant effect on proliferation. These results do not support the existence of regulatory cells specific for CNS antigens. Further investigation into non-antigen-specific mechanisms will be important in defining how autoimmune damage in the CNS is prevented.

Adjuvants, Immunologic↗
PubMed2000

[Identification and functional analysis of NIFA from Mesorhizobium huakuii 159].

The nifA gene from Mesorhizobium huakuii 159 was identified and sequenced. An open reading frame coding for 44734D. NifA protein would detected. Comparison of the deduced amino acid sequence with other NifA proteins revealed the presence of the conserved central domain and the C-terminal DNA-binding domains. But the predicted M. huakuii NifA protein lacked a N-terminal domain that is present in the homologous proteins. Mutants with Nif- phenotype were obtained by site-directed Tn5 mutagenesis. A nifA constitutively expressed plasmid was constructed, and this plasmid could activate the nifH expression in YMC11.

Amino Acid Sequence↗