Biomedical subjects

J Pan

Publications and source records attributed to J Pan.

At least 109 records · Page 6Linked to original sources

PubMed2000

[A study on the deficiency of anticoagulant proteins in Chinese patients with deep venous thrombosis].

OBJECTIVE: To investigate the incidence of anticoagulant proteins deficiency in Chinese patients with venous thrombosis. METHODS: Eighty-seven patients with otherwise unexplained venous thrombophilia were studied. Both the antigen and antivitity of PC, PS, and antithrombin III (ATIII) were determined using commercial kits (Stago, or IL) activated PC, sensitivity ratio (APC-SR) by Coatest chromogenix, and factor V gene mutation by polymerase chain reaction with restriction fragments long polymorphism (PCR-RFLP). RESULTS: Of all the patients twenty-five were found to be abnormal. These consisted of 3 ATIII deficiencies, 5 PC deficiencies, 10 PS deficiencies, 2 resistance of activated protein C (APC-R), 1 combined ATIII and PC deficiency, 1 combined ATIII and PS deficiency, 1 combined PC and PS deficiency, 1 combined APC-R and PC deficiency and 1 combined APC-R and PS deficiency. The overall prevalence of ATIII, PC and PS deficiencies was 26.4%. The patients with anticoagulant proteins deficiency had earlier onset (35.2 +/- 9.7 vs 42.1 +/- 10.9; P < 0.01) and more recurrent thrombosis (P < 0.05), as well as more pulmonary embolism (44.0% vs 16.1%; P < 0.01) than those of without anticoagulant protein deficiency. CONCLUSION: The overall prevalence of ATIII, PC, and PS deficiency in Chinese venous thrombosis patients was higher than that of Western patients. It suggests that the etiology of thrombophilia may be different between Chinese and Western.

Adolescent↗

PubMed2000

[beta-fibrinogen gene -455A/G polymorphism and plasma fibrinogen level in Chinese stroke patients].

OBJECTIVE: To explore the relationship between beta-fibrinogen gene -455A/G polymorphism and plasma fibrinogen level and to determine the influence of the mutation on ischaemic stroke. METHODS: Ninety-one patients (63.5 +/- 10.1 years) with ischaemic stroke, 74 control patients (60.6 +/- 10.8 years) without any thromboembolic events and 98 healthy blood donors (37.5 +/- 13.3 years) were enrolled in this trial. beta-fibrinogen gene -455A/G polymorphism was analyzed from all subjects by polymerase chain reaction-restrictive fragment length polymorphism (PCR-RFLP) with restrictive enzyme Hae III. Plasma fibrinogen levels were obtained from prothrombin time (PT) assay. The parameters were compared between any two different groups by unpaired t-test and Chi-square test. Before the analysis, log transformation was carried out for concentrations of fibrinogen. RESULTS: Frequency of H2 allele was higher in male patients with ischaemic stroke than in control patients (22.7% vs 7.1%, chi(2) = 5.56, P < 0.02). There was no significant difference in female patients. In the subjects without any thromboembolic events (including control patients and healthy blood donors), frequency of H2 decreased with age (>/= 40, 21.3%; 41 approximately 59, 15.4%; >/= 60, 10.0%). Among male control patients and healthy blood donors, the level of plasma fibrinogen was lower in the H1H1 genotype (287 g/L +/- 96 g/L and 234 g/L +/- 58 g/L) than in H1H2 and H2H2 genotypes (331 g/L +/- 44 g/L and 307 g/L +/- 55 g/L; t = 2.53 and 9.67, P < 0.05); among females, this tendency was not found. CONCLUSION: Plasma fibrinogen expression is affected by the beta-fibrinogen gene - 455A/G polymorphism. H2 allele is a risk factor for ischaemic stroke in Chinese men.

Adult↗

PubMed2000

[Function of one novel gene identified by SSH PCR differentially expressed in HBX transfected HepG2 cells].

OBJECTIVE: To clone full length differentially expressed genes which are related with HBxAg. METHODS: HepG2-cells were infected with prepared recombinant retroviruses encoding the X antigen. The differences in gene expression between HepG2 x and HepG2Cat cells were evaluated by suppression subtractive hybridization and PCR. In situ hybridization (ISH) and Northern blot analysis were carried out to screen the differentially expressed genes. The full length cDNA clone of the gene was obtained by 5' and 3' rapid amplification of cDNA ends(race) PCR. HepG2 cells transiently transfected with the new full length gene were subjected to fluorescence activated cell sorting (FACS) analysis for DNA content. HepG2 cells stably transfected with the new full length gene were tested for anchorage independent growth in soft agar and for tumorigenicity in nude mice. RESULTS: The expression of multiple genes were turned on (8) or off (2) in HepG2X compared to HepG2CAT cells. One differentially expressed gene C2, the human homology of Sui1, encoded a translation initiation factor whose expression was suppressed by X antigen in HepG(2) cells. The full length of this gene was 1.35 kb, which encoded a small protein of 113 amino acids. Introduction of C2 into HepG2 cells could inhibit cell growth in culture, in soft agar, and partially inhibit tumor formation in nude mice. Cells transfected with pcDNA3-HBx showed little or no detectable C2, which was consistent with the suppression of this protein in the presence of HBxAg. C2 was also expressed in nontumor liver, but not in tumor cells from patients with hepatocellular carcinoma. CONCLUSIONS: HBX can regulate the expression of genes whose products may be positive or negative regulators of cell growth. Our work for the first time demonstrates that the mechanism of DNA virus associated carcinogenesis involves altered patterns of gene expression regulated at the level of translation initiation.

Amino Acid Sequence↗

PubMed2000

[Clinical experience of long-distance electronic fetal heart rate monitoring system by telephone].

OBJECTIVE: To explore the value of the long-distance electronic fetal heart rate monitoring system by telephone and explore a new way of self-monitoring at home for pregnant woman. METHOD: 204 high risk pregnant women came to our clinic were enrolled in this study. Complications included pregnancy induced hypertension (PIH), intrauterine growth retardation (IUGR), anemia, diabetes, hemolysis, nephropathy. In the study group, 97 women took the terminal part of the fetal heart rate monitoring system home and were requested to auscultate and count fetal heart rate three times a day, while another 107 cases did the self monitoring by fetal movement counting daily and served as control group. For the study group, whenever woman felt any abnormality of her baby, she could contact the long-distance electronic fetal heart rate (FHR) monitoring center in hospital by telephone immediately. The signal of fetal heart beat and fetal movement was converted and analyzed in the electronic FHR monitoring center by computer at the same time. The fetal heart rate curve was printed out, and diagnosis and management could be made. Age, gestational weeks, high risk factors, abnormal non-stress test (NST), Apgar score and birth weight of newborn were analyzed between the experimental and control group retrospectively. RESULTS: There were no obviously differences in age, gestational weeks, weight of newborn, high risk factors between the 2 groups. The incidence of abnormal NST and Apgar score of newborn were significantly higher in the study group than that in the control group, while the incidence of neonatal asphyxia was significantly lower. CONCLUSIONS: This study suggested that the long-distance electronic FHR monitoring by telephone was a reliable, sensitive and applicable method of self-monitoring for pregnant woman at home, use of this system could decrease the incidence of fetal distress, brain damage and perinatal mortality, thus improves the quality of perinatal care.

Adult↗

PubMed2000

[Study on the differentiation and apoptosis of promyelocytic leukemia cells induced by tributyrin].

OBJECTIVE: To investigate the differentiation of NB4 and MR2 cells induced by tributyrin (TB) in combination with different doses of all-trans retinoic acid (ATRA) and to see if TB can induce apoptosis of NB4 and MR2 cells. METHODS: Cell differentiation was analyzed by NBT reduction and CD(11b), CD(14) and CD(33), apoptosis by morphology, DNA electrophoresis, flow cytometry (FCM) and TUNEL in situ hybridization, bcl-2 expression by reverse transcriptase polymerase chain reaction. RESULTS: 0.2 mmol/L TB in combination with different doses of ATRA could potentiate the differentiation of NB4 cells induced by ATRA alone. No MR2 cell could be markedly induced by ATRA alone or in combination with TB. Treated with 1 mmol/L TB for 24 hours NB4 and MR2 cells exhibited a morphological characteristic of apoptosis and typical DNA ladder on gel electrophoresis. FCM analysis showed that TB could interfere with cell cycle in NB4 and MR2 cells, with a similar ratio of sub-G(1) in both cell lines. TUNEL in situ hybridization confirmed these results. Further study showed that TB could gradually down-regulated bcl-2 expression. CONCLUSION: TB exerts synergetic effect on ATRA-induced differentiation and induces apoptosis in promyelocytic leukemic cells.

Apoptosis↗

PubMed2000

[Detection of trisomy 8 with interphase fluorescence in situ hybridization in myelodysplastic syndromes].

OBJECTIVE: To explore the value of interphase fluorescence in situ hybridization (FISH) in the detection of trisomy 8 in myelodysplastic syndromes (MDS). METHODS: Conventional cytogenetics (CC) and interphase FISH using SpectrumGreen labelled chromosome 8 centromere specific probe were simultaneously carried out to detect trisomy 8 in 69 MDS and 6 normal individuals. RESULTS: Two hundred interphase cells were counted and cells with three green hybridization spots > 3% was assigned. Eleven cases displayed trisomy 8 by CC and were confirmed in 10 by FISH. In 7 cases, the percentage of trisomy 8 cells was significantly lower by FISH than by CC. Seven cases displayed trisomy 8 by FISH in 58 cases who did not show trisomy 8 by CC. Of the 7 cases, two had 2 and 3 marker chromosomes respectively, 4 had normal karyotypes. CONCLUSIONS: Interphase FISH was a useful method for the detection of trisomy 8 in MDS, especially in patients with normal karyotype or marker chromosome. It was a important complement to CC.

Adult↗

PubMed2000

[Anti-CD40 McAb induces CD40+ malignant B cell proliferation arrest and apoptosis].

OBJECTIVE: To study the expression of CD(40) molecule and the biological effects mediated by CD(40) molecules on malignant B cells. METHODS: Agonistic anti-human CD(40) monoclonal antibody (5C11) was added to the cell culture system. Cell counting, PI staining, Annexin-V staining and flow cytometric analysis were used to study the biological effects of 5C11 on malignant B cell lines. RESULTS: 5C11 induced homotypic aggregation, proliferation arrest and apoptosis in the multiple myeloma cell line XG2 highly expressed CD(40). 5C11 induced B lymphoma cell line Daudi homotypic aggregation and proliferation arrest but no apoptosis. CONCLUSION: 5C11 can inhibit proliferation of malignant B cells by inducing apoptosis or arresting the cells at G(2)/M interphase.

Antibodies, Monoclonal↗

PubMed2000

[The rearrangements of immunoglobulin heavy chain and T cell receptor delta genes in patients with acute nonlymphocytic leukemia].

OBJECTIVE: To explore the clinical significance of rearrangements of immunoglobulin heavy chain (IgH) and T cell receptor (TCR) genes in patients with acute nonlymphocytic leukemias. METHODS: Polymerase chain reaction (PCR) was used to study IgH and TCRdelta genes rearrangements in 30 untreated acute nonlymphocytic leukemia patients. RESULTS: IgH gene rearrangements were found in 9 patients, and TCRdelta gene rearrangements in 5 patients. CONCLUSION: The lineage infidelity does occur in acute nonlymphocytic leukemia, showing not only a high frequency of IgH gene rearrangement, but also of TCRdelta gene rearrangement.

Gene Rearrangement↗

PubMed2000

[Protection of hematopoietic stem cells by MIP-1alpha and PF4 against the cytotoxicity of chemotherapeutic agents].

OBJECTIVE: To study the protective effects of macrophage inflammatory protein-1alpha (MIP-1alpha) and platelet factor 4 (PF4), alone and in combination, on hematopoietic stem/progenitor cells against the cytotoxicity of chemotherapeutic drugs. METHODS: Bone marrow and cord blood mononuclear cells (BMMNC and CBMNC) and HL-60 cells were pretreated with MIP-1alpha, PF4, MIP-1alpha + PF4, and PBS respectively for 48 hours, and then incubated with DNR for an additional 24 hours. Cell viability, cell cycle, CD(34)(+) CD(38)(-) cells, colony forming units (CFU) and protein expression of p16, p27 gene were measured. RESULTS: (1) Cell viability, the number of CD(34)(+) CD(38)(-) cells and CFU yields of BMMNC and CBMNC in MIP-1alpha and PF4 groups were significantly higher than that in control groups (P < 0.05). (2) Cells in S + G(2) phase in MIP-1alpha and PF4 groups were significantly fewer than that in control groups (P < 0.05). (3) MIP-1alpha upregulated the expression of p16 gene of stem/progenitor cells. PF4 showed no effects on expression of both p16 and p27 genes. (4) Hematopoietic protection of MIP-1alpha was stronger than that of PF4. No cooperative effect could be seen in combination of the two agents. (5) Cell viability, cell cycle and expression of p16 and p27 gene of HL-60 cells were not affected by either MIP-1alpha or PF4. CONCLUSION: MIP-1alpha and PF4 can reversibly and selectively protect hematopoietic stem/progenitor cells against cytotoxicity of chemotherapeutic agents. MIP-1alpha can suppress cell proliferation by upregulating the expression of p16 gene and block the cell cycle at G(0) phase, resulting in the elevation of cell resistance to chemotherapeutic drugs.

ADP-ribosyl Cyclase↗

PubMed2000

[A study of the relation between ventricular repolarization duration and autonomic nervous system].

Cardiovascular disease is a growing problem recently. There has been a few attention in the study of ventricular repolarization duration variability. RDV is associated with some cardiac diseases. We studied vagal blockade effects on RDV in urethane-anesthetized rats. To study the relation between ventricular repolarization duration and autonomic nervous system in subjects, we changed the balance of autonomic nervous system by body posture. The HRV and RDV spectral analysis showed that HF peak was modulated by the frequency of controlled respiration. We also found a significant decrease in HFnu and increase in LF/HF in HRV and RDV during vagal blockade. There is a significant increase of LF/HF of subjects in HRV and RDV from supine to tilt, which is consistent with the state of autonomic nervous system. The result of our study is that the ventricular repolarization duration is dependent on the autonomic nervous system. The RDV analysis will be more helpful in the clinic. This approach will provide a more useful noninvasive evaluation of cardiac disease and function.

Adult↗

PubMed2000

[Quantitative analysis of 4(3)-quinazolinedione in 4 "daqingye", leave of Isatis indigotica, Baphicacanthus cusia, Polygonum tinctorium and Clerodendron cyrtophyllum].

Using 4(3)-quinazolinedione, the active constituent of "Daqingye", as the quality control criteria, 4 samples of the herbal drug collected from Isatis indigotica, Baphicacanthus cusia, Polygonum tinctorium and Clerodendron cyrtophyllum were comparetively analyzed by RP-HPLC. The results showed that the average 4(3)-quinazolinedione contents (microgram/g) were 30.7, 7.2, 4.4 and 27.5 respectively. This method was proved to be quick, simple and reproducible, and provided a reliable basis for the quality control and evaluation of Chinese Traditional Drug "Daqingye".

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2000

[The spectra and thermodynamics of axial coordination reaction of tailed valine tetraphenylporphintozinc with pyrimidine].

The electronic absorption spectra and thermodynamics of axial coordination reaction of 5-(4-valine butoxyphenyl)-10,15,20-tri(4-chlorophenyl)porphintozinc with pyrimidine in CHCl3 were studied. Coordination numbers and equilibrium constants of axial coordination reaction were measured by visible spectra techniques. The changes of standard molar enthalpies and standard molar entropies of reaction were obtained from the plots of ln beta vs 1/T. The influence of temperature on the axial reaction was discussed.

Porphyrins↗

PubMed1999

The effect of long-range loop-loop interactions on folding of the Tetrahymena self-splicing RNA.

Bas?e-pairing between the terminal loops of helices P2.1 and P9.1a (P13) and P2 and P5c (P14) stabilize the folded structure of the Tetrahymena group I intron. Using native gel electrophoresis to analyze the folding kinetics of a natural pre-RNA containing the Tetrahymena intron, we show that P13 and P14 are the only native loop-loop interactions among six possible combinations. Other base-pairing interactions of the loop sequences stabilize misfolded and inactive pre-RNAs. Mismatches in P13 or P14 raised the midpoints and decreased the cooperativity of the Mg(2+)-dependent eqXuilibrium folding transitions. Although some mutations in P13 resulted in slightly higher folding rates, others led to slower folding compared to the wild-type, suggesting that P13 promotes formation of P3 and P7. In contrast, mismatches in P14 increased the rate of folding, suggesting that base-pairing between P5c and P2 stabilizes intermediates in which the catalytic core is misfolded. Although the peripheral helices stabilize the native structure of the catalytic core, our results show that formation of long-range interactions, and competition between correct and incorrect loop-loop base-pairs, decrease the rate at which the active pre-RNA structure is assembled.

Animals↗

PubMed1999

Hypertrophic stimuli augment expression of cMG1/ERF-1, a putative zinc-finger motif transcription factor, in rat cardiomyocytes.

We isolated the gene for cMG1/ERF-1, a known putative zinc-finger transcription factor, by differential display of mRNA extracted from cardiomyocytes with and without leukemia inhibitory factor (LIF) stimulation. LIF induced cMG1/ERF-1 mRNA at 15 min, and levels peaked at 10-fold initial levels at 30 min. cMG1/ERF-1 expression was inhibited by AG490 (JAK2 inhibitor) and genistein, but was unaffected by PD98059 or wortmannin. Phenylephrine, angiotensin II and endothelin-1 also induced cMG1/ERF-1 expression. Mechanical stretch in vitro and acute pressure overload in vivo increased cMG1/ERF-1 expression. To our knowledge, this is the first report showing that the cMG1/ERF-1 gene can be induced by various hypertrophic stimuli, and that Janus kinase 2 is involved in this process.

Angiotensin II↗

PubMed1999

Characterization of insulin-like growth factor-1-induced activation of the JAK/STAT pathway in rat cardiomyocytes.

This study was designed to investigate whether insulin-like growth factor-1 (IGF-1) transduces signaling through the Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway in cardiomyocytes and to assess the upstream signals of serine and tyrosine phosphorylation of STAT family proteins. Primary cultured neonatal rat cardiomyocytes were stimulated with IGF-1 (10(-8) mol/L). JAK1, but not JAK2 or Tyk2, was phosphorylated by IGF-1 as early as 2 minutes and peaked at 5 minutes. IGF-1 induced both tyrosine and serine phosphorylation of STAT1 and STAT3. Tyrosine phosphorylation of STAT1 peaked at 15 minutes and correlated with that of JAK1, whereas that of STAT3 was sustained up to 120 minutes and was dissociated from the activation of JAK1. Tyrosine phosphorylation of STAT3 was unaffected by the preincubation with CV11974 (AT(1) blocker), TAK044 (endothelin-1 receptor blocker), RX435 (anti-gp130 blocking antibody), PD98058, wortmannin, EDTA, or KN62 but was significantly attenuated by BAPTA-AM and chelerythrine. The time course of a gel mobility shift of SIE (sis-inducing element) coincided with the phosphorylation of STAT3. Serine phosphorylation of STAT1 peaked at 30 minutes and that of STAT3 was observed from 5 to 60 minutes. These results indicated that (1) IGF-1 activated JAK1 but not JAK2 or Tyk2 in rat cardiomyocytes; (2) IGF-1 induced both tyrosine and serine phosphorylation of STAT1 and STAT3; and (3) the tyrosine phosphorylation of STAT3 was not caused by JAK1 alone, and protein kinase C and intracellular Ca(2+) were required for phosphorylation.

Animals↗

PubMed1999

Metabolism of methyl tert-butyl ether and other gasoline ethers by human liver microsomes and heterologously expressed human cytochromes P450: identification of CYP2A6 as a major catalyst.

To reduce the production of carbon monoxide and other pollutants in motor vehicle exhaust, methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) are added to gasoline as oxygenates for more complete combustion. Previously, we demonstrated that human liver is active in metabolizing MTBE to tert-butyl alcohol (TBA) and that cytochrome P450 (CYP) enzymes play a critical role in the metabolism of MTBE. The present study demonstrates that human liver is also active in the oxidative metabolism of ETBE and TAME. A large interindividual variation in metabolizing these gasoline ethers was observed in 15 human liver microsomal samples. The microsomal activities in metabolizing MTBE, ETBE, and TAME were highly correlated among each other (r, 0.91-0. 96), suggesting that these ethers are metabolized by the same enzyme(s). Correlation analysis of the ether-metabolizing activities with individual CYP enzyme activities in the liver microsomes showed that the highest degree of correlation was with human CYP2A6 (r, 0. 90-0.95), which is constitutively expressed in human livers and known to be polymorphic. CYP2A6 displayed the highest turnover number in metabolizing gasoline ethers among a battery of human CYP enzymes expressed in human B-lymphoblastoid cells. Kinetic studies on MTBE metabolism with three human liver microsomes exhibited apparent Km values that ranged from 28 to 89 microM and the V(max) values from 215 to 783 pmol/min/mg, with similar catalytic efficiency values (7.7 to 8.8 microl/min/mg protein). Metabolism of MTBE, ETBE, and TAME by human liver microsomes was inhibited by coumarin, a known substrate of human CYP2A6, in a concentration-dependent manner. Monoclonal antibody against human CYP2A6 caused a significant inhibition (75% to 95%) of the metabolism of MTBE, ETBE, and TAME in human liver microsomes. Taken together, these results clearly indicate that in human liver, CYP2A6 is the major enzyme responsible for the metabolism of MTBE, ETBE, and TAME.

Aryl Hydrocarbon Hydroxylases↗

PubMed1999

Cutting edge: developmental switches in chemokine responses during T cell maturation.

We show that developmental transitions during thymocyte maturation are associated with dramatic changes in chemotactic responses to chemokines. Macrophage-derived chemokine, a chemokine expressed in the thymic medulla, attracts thymocytes only during a brief window of development, between the late cortical and early medullary stages. All medullary phenotypes (CD4 or CD8 single positive) but not immature thymocytes respond to the medullary stroma-expressed (and secondary lymphoid tissue-associated) chemokines secondary lymphoid-tissue chemokine and macrophage inflammatory protein-3beta. The appearance of these responses is associated with the phenotypic stage of cortex to medulla migration and with up-regulation of mRNA for the receptors CCR4 (for macrophage-derived chemokine and thymus and activation-regulated chemokine) and CCR7 (for secondary lymphoid-tissue chemokine and macrophage inflammatory protein-3beta). In contrast, most immature and medullary thymocytes migrate to thymus-expressed chemokine, an ability that is lost only with up-regulation of the peripheral homing receptor L-selectin during the latest stages of thymocyte maturation associated with export to the periphery. Developmental switches in chemokine responses may help regulate critical migratory events during T cell development.

Animals↗

PubMed1999

The chemokine receptor CCR4 in vascular recognition by cutaneous but not intestinal memory T cells.

Lymphocytes that are responsible for regional (tissue-specific) immunity home from the blood to the intestines, inflamed skin or other sites through a multistep process involving recognition of vascular endothelial cells and extravasation. Chemoattractant cytokine molecules known as chemokines regulate this lymphocyte traffic, in part by triggering arrest (stopping) of lymphocytes rolling on endothelium. Here we show that many systemic memory T cells in blood carry the chemokine receptor CCR4 and therefore respond to its ligands, the chemokines TARC and MDC. These cells include essentially all skin-homing cells expressing the cutaneous lymphocyte antigen and a subset of other systemic memory lymphocytes; however, intestinal (alpha4beta7+) memory and naive T cells respond poorly. Immunohistochemistry reveals anti-TARC reactivity of venules and infiltration of many CCR4+ lymphocytes in chronically inflamed skin, but not in the gastrointestinal lamina propria. Moreover, TARC induces integrin-dependent adhesion of skin (but not intestinal) memory T cells to the cell-adhesion molecule ICAM-1, and causes their rapid arrest under physiological flow. Our results suggest that CCR4 and TARC are important in the recognition of skin vasculature by circulating T cells and in directing lymphocytes that are involved in systemic as opposed to intestinal immunity to their target tissues.

Chemokine CCL17↗