Search PubMed⌕ Search

Biomedical subjects

Hong Jiang

Publications and source records attributed to Hong Jiang.

At least 181 records · Page 10Linked to original sources
PubMed2002

Activation of Rap1B by G(i) family members in platelets.

It has become increasingly appreciated that receptors coupled to G(alpha)(i) family members can stimulate platelet aggregation, but the mechanism for this has remained unclear. One possible mediator is the small GTPase, Rap1, which has been shown to contribute to integrin activation in several cell lines and to be activated by a calcium-dependent mechanism in platelets. Here, we demonstrate that Rap1 is also activated by G(alpha)(i) family members in platelets. First, we show that platelets from mice lacking the G(alpha)(i) family member G(alpha)(z) (which couples to the alpha(2A) adrenergic receptor) are deficient in epinephrine-stimulated Rap1 activation. We also show that platelets from mice lacking G(alpha)(i2), which couples to the ADP receptor, P2Y12, exhibit reduced Rap1 activation in response to ADP. In contrast, platelets from mice that lack G(alpha)(q) show no decrease in the ability to activate Rap1 in response to epinephrine but show a partial reduction in ADP-stimulated Rap1 activation. This result, combined with studies of human platelets treated with ADP receptor-selective inhibitors, indicates that ADP-stimulated Rap1 activation in human platelets is dependent on both the G(alpha)(i)-coupled P2Y12 receptor and the G(alpha)(q)-coupled P2Y1 receptor. G(alpha)(i)-dependent activation of Rap1 in platelets does not appear to be mediated by enhanced intracellular calcium release because no increase in intracellular calcium concentration was detected in response to epinephrine and because the calcium response to ADP was not diminished in platelets from the G(alpha)(i2)-/- mouse. Finally, using human platelets treated with selective inhibitors of phosphatidylinositol 3-kinase (PI3K) and mouse platelets selectively lacking the G(beta)(gamma)-activated form of his enzyme (PI3Kgamma), we show that G(i)-mediated Rap1 activation is PI3K-dependent. In summary, activation of Rap1 can be stimulated by G(alpha)(i)- and PI3K-dependent mechanisms in platelets and by G(q)- and Ca(2+)-dependent mechanisms, both of which may play a role in promoting platelet activation.

Adenosine Diphosphate↗
PubMed2002

A requirement for the CD44 cytoplasmic domain for hyaluronan binding, pericellular matrix assembly, and receptor-mediated endocytosis in COS-7 cells.

CD44-negative COS-7 cells were transfected with expression constructs for CD44H (the predominant CD44 isoform), CD44E (epithelial isoform), or truncation mutant derivatives lacking the carboxyl-terminal 67 amino acids of the cytoplasmic domain, CD44HDelta67 and CD44EDelta67. The truncation mutant CD44HDelta67 is identical to a naturally occurring alternatively spliced "short tail" CD44 isoform (CD44st), which incorporates exon 19 in place of exon 20. CD44st lacks intracellular signaling motifs as well as protein domains necessary for interaction with cytoskeletal components. Transfection of COS-7 cells with each construct yielded equivalent levels of mRNA expression, whereas no CD44 expression was observed in parental, nontransfected COS-7 cells. Western analysis and immunostaining of COS-7 transfectants confirmed CD44 protein expression of the truncation mutant derivatives. COS-7 cells transfected with CD44H or CD44E gained the capacity to bind fluorescein-conjugated HA (fl-HA) and assemble HA-dependent pericellular matrices in the presence of exogenously added HA and proteoglycan. In addition, the CD44H- and CD44E-transfected cells were able to internalize surface-bound fl-HA. COS-7 cells transfected with the vector alone or with either of the mutant CD44 isoforms, CD44HDelta67 or CD44EDelta67, did not exhibit the capacity to assemble pericellular matrices or to bind and internalize the fl-HA. Cotransfection of CD44Delta67 mutants together with CD44H reduced the size of the HA-dependent pericellular matrices. Transfection of bovine articular chondrocytes with CD44Delta67 also inhibited pericellular matrix assembly. Collectively, these results indicate an obligatory requirement for the CD44 receptor cytoplasmic domain for ligand (HA) binding, formation and retention of the pericellular matrix, as well as CD44-mediated endocytosis of HA. In addition, the results suggest a potential regulatory role for the differentially expressed alternatively spliced short tail CD44 isoform.

3' Untranslated Regions↗
PubMed2002

C/T polymorphism of the intercellular adhesion molecule-1 gene (exon 6, codon 469). A risk factor for coronary heart disease and myocardial infarction.

BACKGROUND: The intercellular adhesion molecule-1 (ICAM-1) mediates the interaction of activated endothelial cells with leukocytes and plays a fundamental role in the pathogenesis of coronary atherosclerosis. ICAM-1 single-base C/T polymorphism, which determines an amino acid substitution in the ICAM-1 protein in exon 6 codon 469, has been described. Our purpose was to determine whether this C/T polymorphism influences the risk of coronary heart disease (CHD) and myocardial infarction (MI) in humans. METHODS AND RESULTS: We enrolled 349 patients with angiographically documented CHD, including a sub-group of 179 patients with acute or chronic MI. The control group consisted of 213 patients with normal left ventricular function and no documented evidence of CHD. All patients and controls were Germans genotyped by polymerase chain reaction and allele-specific oligonucleotide techniques for the ICAM-1 polymorphism. In the patients with CHD and MI the frequencies of the T genotype (TT+TC) were significantly higher than the CC genotype compared to the control subjects (P<0.001). With the additional use of multivariable logistic regression analysis for CHD (TT+TC versus CC; P=0.011, odds ratio 2.21, 95% CI 1.20-4.07), we found a significant association between CHD and MI and the TT and TC genotype of the ICAM-1 gene polymorphism. CONCLUSIONS: These results suggest that the TT and TC genotype of the ICAM-1 gene polymorphism in codon 469 is a genetic factor that may determine an individual's susceptibility for CHD and MI.

Aged↗
PubMed2002

Expanded CUG repeats trigger aberrant splicing of ClC-1 chloride channel pre-mRNA and hyperexcitability of skeletal muscle in myotonic dystrophy.

In myotonic dystrophy (dystrophia myotonica, DM), expression of RNAs that contain expanded CUG or CCUG repeats is associated with degeneration and repetitive action potentials (myotonia) in skeletal muscle. Using skeletal muscle from a transgenic mouse model of DM, we show that expression of expanded CUG repeats reduces the transmembrane chloride conductance to levels well below those expected to cause myotonia. The expanded CUG repeats trigger aberrant splicing of pre-mRNA for ClC-1, the main chloride channel in muscle, resulting in loss of ClC-1 protein from the surface membrane. We also have identified a similar defect in ClC-1 splicing and expression in two types of human DM. We propose that a transdominant effect of mutant RNA on RNA processing leads to chloride channelopathy and membrane hyperexcitability in DM.

Alternative Splicing↗
PubMed2002

Group intervention for children bereaved by the suicide of a relative.

OBJECTIVE: This study evaluated efficacy of a manual-based bereavement group intervention for children who suffered suicide of a parent or sibling. METHOD: Seventy-five families (102 children) were screened from medical examiners' lists of suicide victims. Fifty-two families (75 children) were eligible and assigned in alternating order to receive (27 families, 39 children) or not to receive (25 families, 36 children) the intervention. Intervention efficacy was evaluated as change in children's symptoms of anxiety, depression, posttraumatic stress, social adjustment, and parents' depressive symptoms from initial to outcome assessments. RESULTS: Changes in anxiety and depressive symptoms were significantly greater among children who received the intervention than in those who did not. A greater dropout of children assigned not to receive (75%) than to receive (18%) intervention led to an imbalance in retention of intervention and nonintervention participants. CONCLUSIONS: A bereavement group intervention focusing on reactions to death and suicide and strengthening coping skills can lessen distress of children bereaved after parental or sibling suicide. Such intervention may prevent future morbidities.

Adaptation, Psychological↗
PubMed2002

Adenosine kinase inhibition promotes survival of fetal adenosine deaminase-deficient thymocytes by blocking dATP accumulation.

Thymocyte development past the CD4(-)CD8(-) stage is markedly inhibited in adenosine deaminase-deficient (ADA-deficient) murine fetal thymic organ cultures (FTOCs) due to the accumulation of ADA substrates derived from thymocytes failing developmental checkpoints. Such cultures can be rescued by overexpression of Bcl-2, suggesting that apoptosis is an important component of the mechanism by which ADA deficiency impairs thymocyte development. Consistent with this conclusion, ADA-deficient FTOCs were partially rescued by a rearranged T cell receptor beta transgene that permits virtually all thymocytes to pass the beta-selection checkpoint. ADA-deficient cultures were also rescued by the adenosine kinase inhibitor 5'-amino-5'-deoxyadenosine (5'A5'dAdo), indicating that the metabolite responsible for the inhibition of thymocyte development is not adenosine or deoxyadenosine, but a phosphorylated derivative of an ADA substrate. Correction of ADA-deficient FTOCs by 5'A5'dAdo correlated with reduced accumulation of dATP, implicating this compound as the toxic metabolite. In ADA-inhibited FTOCs rescued with a Bcl-2 transgene, however, dATP levels were superelevated, suggesting that cells failing positive and negative selection continued to contribute to the accumulation of ADA substrates. Our data are consistent with dATP-induced mitochondrial cytochrome c release followed by apoptosis as the mechanism by which ADA deficiency leads to reduced thymic T cell production.

Adenosine Deaminase↗
PubMed2002

Comparative study of catheter-mediated gene transfer into heart.

OBJECTIVE: To investigate the feasibility and features of 3 catheter-mediated approaches of gene transfer into heart, including direct myocardial injection (DMI), coronary artery perfusion (CAP), and intrapericardial cavity injection (ICI). METHODS: Fifteen dogs were used, and 0.3 ml (1 x 10(9) pfu) of an adenovirus (Adex1SR LacZ) was injected into the heart by 3 methods. The dogs were killed 5 days following injection, and gene expressions in heart and liver were evaluated by histochemical analysis. RESULTS: The results showed that (1) the CAP method was relatively less damaging and induced sparse LacZ expression in the myocardium, and the gene expression was also found in both vessels within the myocardium and liver; (2) gene transfer by DMI resulted in intense LacZ expression around the injection accompanied by a local inflammatory response; (3) LacZ expression elicited by ICI was detected in either the inner surface of the parietal pericardium or epicardial surface of the heart, and also in the myocardium underlying the visceral pericardium. CONCLUSION: Three catheter-mediated methods of gene transfer into the heart may be used and a reasonable approach should be chosen according to purpose.

Adenoviridae↗
PubMed2002

Detection of enteroviral RNA (poliovirus types 1 and 3) in endomyocardial biopsies from patients with ventricular tachycardia and survivors of sudden cardiac death.

The purpose of this study was to determine the prevalence of enteroviral infection in the myocardium of consecutive patients with serious ventricular arrhythmias by using a reverse transcription nested PCR followed by direct DNA sequencing. After exclusion of coronary heart disease, right ventricular endomyocardial biopsies were obtained from 32 consecutive patients with a history of ventricular tachycardia or sudden cardiac death. Control biopsies were obtained from 36 subjects with no history of viral myocarditis, dilated cardiomyopathy, ventricular tachycardia or recent infection. Enteroviral genome was found in endomyocardial biopsies from 4/32 patients (12.5%), 2 with a history of ventricular tachycardia and 2 with a history of ventricular fibrillation. Three of these 4 enteroviral RNA-positive patients had dilated cardiomyopathy and the other had normal cardiac geometry and ventricular function. In the latter and in 1 patient with enteroviral-positive dilated cardiomyopathy, an active inflammatory process in the myocardium was found by means of immunohistology. Enteroviral RNA in the myocardium of 3 patients had the highest homology to poliovirus type 1 (strain CHAT 10A-11) and in the other was similar to poliovirus type 3 (strain P3/119). All control samples were negative for enteroviral RNA. In summary, these findings raise the possibility that enteroviruses, such as poliovirus types 1 and 3, may be involved in the pathogenesis of ventricular tachycardia and sudden cardiac death.

Base Sequence↗
PubMed2002

[Clinical value of antenatal diagnosis of intrauterine active human cytomegalovirus infection with reverse transcription polymerase chain reaction].

OBJECTIVE: To study the clinical value of antenatal diagnosis of intrauterine active human cytomegalovirus (HCMV) infection with reverse transcription polymerase chain reaction (RT-PCR). METHODS: The active HCMV infection of pregnant women was diagnosed with enzyme-linked immunosorbent assay (ELISA), serum Nest-PCR (N-PCR) and RT-PCR. The methods of antenatal diagnosis include villus sampling, amniocentesis and cordocentesis under ultrasound guidance. RT-PCR and N-PCR was used to screen fetal active infection. RESULTS: The infection rate of chorionic villi and cord blood whose mother was in active infection is 53.3% (16/30) and 47.8% (33/69) respectively, whereas that whose mother just had infectious history is 8.3% (4/48), 9.7% (6/62) respectively, the differences are statistically significant respectively (P < 0.001). The active infection rate of chorionic villi and cord blood in maternal active infection group is 30.0% (9/30) and 29.0% (20/69) respectively, whereas that with infectious history is 4.2% (2/48) and 4.8% (3/62), the differences are statistically significant respectively (P < 0.001). In the active intrauterine infection, the incidence of abortion and premature delivery was 41.2% (14/34), significantly higher than that of the latent infection 8.0% (2/25, P < 0.01). CONCLUSIONS: Antenatal diagnosis of intrauterine active HCMV infection with RT-PCR and the means of sampling described are of safety and reliability. It has a great clinical value in management of the fetus whose mother had been in active HCMV infection.

Cytomegalovirus Infections↗
PubMed2002

Diagnostic value of human cytomegalovirus late mRNA detection in active intrauterine infection.

OBJECTIVE: To study the diagnostic value of human cytomegalovirus (HCMV) late mRNA detection in active intrauterine infection. METHODS: The HCMV late mRNA in peripheral blood of 42 HCMV IgM positive pregnant women and their fetal attachments (such as chorionic villi, amniotic fluid, umbilical blood and placenta) were detected by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Late mRNA was detected in 23 of 42 HCMV IgM positive cases, a rate of 54.3%. Fetal appendages in 13 cases of late mRNA positive mothers were also tested, of which 7 were positive, with a vertical transmission rate of 53.8%. In 12 late mRNA negative mothers, only 1 case of fetal appendages tested was positive, with a vertical transmission rate of 8.3%. There was significant difference between the transmission rates of these two groups. CONCLUSIONS: Positive results of HCMV IgM cannot accurately reflect the activity of HCMV at the time of testing. However, the activity of HCMV is closely related to the mother-fetus vertical transmission rate. As an indicator of active HCMV infection, late mRNA can not only reflect the mother-fetus transmission rate during active HCMV infection, but also provide some information about HCMV activity in fetal tissue.

Antibodies, Viral↗
PubMed2002

Effect of arsenic trioxide on inhibition of restenosis after rabbit vascular injury and its mechanism.

OBJECTIVE: To investigate the effect and mechanism of arsenic trioxide (As(2)O(3)) on the prevention of restenosis after vascular injury. METHODS: Apoptosis induction of As(2)O(3) on cultured rabbit vascular smooth muscle cells (VSMCs) in vitro was observed. Thirty-two New Zealand white rabbits were randomly divided into 2- and 4-wk study groups, and their controls. 10% As(2)O(3) at 2.5 mg x Kg(-1) x d(-1) or 0.9% sodium chloride was intraperitoneally infused for 3 days before left common carotid arteries were denudated with a balloon. After denudation 2- and 4-wk animals were sacrificed for morphometry and immunohistochemical studies on carotid arteries, and for histopathology on liver and kidney. RESULTS: It was shown via cellular morphology and DNA fragments in electrophoresis that promotion of As(2)O(3) on cultured vascular smooth muscle cell apoptosis was dependent upon its concentration and duration. Compared with the control animals, the mean vascular intimal proliferation areas were reduced in 2-wk study animals (P < 0.05) and no difference was shown in 4-wk (P > 0.05), while the mean vascular luminal areas were all enlarged in both study groups (all P < 0.05). The downregulated bcl-2 expression (all P < 0.05 in 2- and 4-wk) and the upregulated bax expression (P < 0.01 in 2-wk; P < 0.05 in 4-wk) were detected by immunohistochemistry, in comparison with control groups. Gene bcl-2 and bax protein expression were consistent with the suppression of intimal proliferation and the enlargement of luminal areas in corresponding sections. CONCLUSION: As(2)O(3) induces apoptosis of VSMCs and inhibits experimental restenosis effectively after artery injury, via downregulation of bcl-2 and upregulation of bax expression.

Animals↗
PubMed2002

Detection of B lymphoma cells undergoing apoptosis by Annexin-V assay.

OBJECTIVE: To quantitatively analyze apoptotic and secondary necrotic cells under apoptosis conditions. METHODS: The cells of Burkitt lymphoma (BL) cell line Raji were incubated with 1.0 micromol/L dexamethasone (DEX) for 2, 4 and 8 h respectively, then stained with Annexin V-FITC (fluorescein isothiocyanate conjugated) which was used to detect the exposed phosphatidylserine (PS) on the epimembrane resulting from a loss of phospholipid asymmetry in the early stage of apoptosis, and also stained with propidium iodide (PI) which allows analysis of secondary necrotic cells related with cell membrane and DNA damage that probably representlate stage of apoptosis, then apoptotic cells were quantified by flow cytometry (FCM). Furthermore, Annexin+ /PI- and Annexin+ /PI+ cells were sorted by fluoresence-activated cell sorter (FACS), and identified by electron microscopy (EM) and DNA gel electrophoresis. RESULTS: The percentage of apoptotic cells was found to increase with the incubation time (r = 0.97). This method was sensitive with low detection limit (0.02%), and was reproducible with low coefficient variance (CV) (4.2%). Meanwhile, the Annexin+ /PI- and Annexin+ /PI+ cells were identified as apoptotic and necrotic cells under EM, and DNA extracted from the Annexin+ /PI- cells was characterized by "ladder pattern". CONCLUSIONS: Annexin-V assay is a specific, sensitive, accurate, reproductive and quantitative method for analyzing apoptotic cells.

Annexin A5↗
PubMed2002

[The study of psychological factors and SIgA content in saliva of patients with temporomandibular disorders].

OBJECTIVE: To study the personality, stress, harmful emotions, coping styles and oral immune change of patients with TMD. METHODS: Using MMPI, LES, Trait coping inventory, SDS, and SAS to test patients and normal control, and using radiate-immune method to determine SIgA content in saliva. RESULTS: The scores of TMD patients in MMPI were significantly higher than those of the normal control (P<0.05, P<0.01), and 10 patients' MMPI results were abnormal. The scores of TMD patients in negative life event and work event were significantly higher than those of the normal control (P<0.05, P<0.01). The scores of TMD patients in PC were significantly lower than those of the normal control, but which in NC were significantly higher than those of the normal control (P<or=0.05, P<0.01). The SAS, SDS scores of TMD patients were significantly higher than those of the normal control (P<0.01). The SIgA contents of TMD patients were significantly lower than those of the normal control (P<0.01),and which were significantly correlated to SDS scores (r=-0.320,P<0.05). CONCLUSION: TMD patients had abnormal personality, more negative life changes, more negative coping style and harmful emotions, which can induce the high and chronic stress and depression of oral immune function. It may be one of the causes of TMD.

English Abstract↗
PubMed2001

Molecular Cloning of Genes Related to Apoptosis in Spermatogenic Cells of Mouse.

An apoptotic model of spermatogenic cells of mouse has been established by the method of operative cryptorchidism. By using light microscope and electronmicroscope, as well as TUNEL-stain (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling method), it had been confirmed that operative cryptorchidism could successfully induce apoptosis of spermatogenic cells of mouse.On the basis of this research, 24 ESTs (expressed sequence tags) of the genes related to apoptosis in spermatogenic cells have been isolated and cloned by the method of suppression subtractive hybridization(SSH). After being confirmed with PCR and digestion by restriction enzyme PstI, they were sequenced and searched in GenBank for homology analysis. All of those were novel ESTs and were banked into GenBank with accession numbers. With the probes derived from three arbitrary cDNA sequences, Northern hybridization confirmed that there was obvious differential expression between cryptorchid testis and contralateral testis. These results suggest that experimental cryptorchidism is a suitable model for studying gene expression in the process of hypospermatogenesis and spermatogenic cell apoptosis, and ESTs isolated from this work may be involved in this apoptosis.

Journal Article↗
PubMedDate not supplied

Bioremediation of organophosphorus pesticides by surface-expressed carboxylesterase from mosquito on Escherichia coli.

The insecticide resistance-associated esterase, carboxylesterase B1 (CaE B1), from mosquito was used to degrade the organophosphorus compounds. To eradicate the need for enzyme purification and minimize the resistance to mass transport of the substrate and product across the cell membranes, the CaE B1 was displayed on the cell surface of Escherichia coli fused to the C-terminus of the ice nucleation protein (INP). The presence of CaE B1 on the bacterial cell surface was verified by SDS-PAGE, Western blotting analysis, and immunofluorescence microscopy. More than 50% of active CaE B1 is exported across the membrane and anchored onto the cell surface as determined by proteinase accessibility and cell fractionation experiments. In contrast, only a 6% drop in activity for proteinase K-treated cells was detected from E.coli cells containing pET-B1. From the degradation experiment, more than 80% of the malathion was degraded by whole cells containing plasmid pUC-NC-B1. Constitutive expression of CaE B1 on the surface using INPNC resulted in no cell lysis, and the suspended cultures also exhibited good stability. Because of their high biodegradation activity and superior stability, these "live biocatalysts" are promising for detoxification of organophosphorus pesticides.

Animals↗
PubMedDate not supplied

Elevated level of plasma C-reactive protein in patients with unstable angina: its relations with coronary stenosis and lipid profile.

C-reactive protein (CRP) is a sensitive marker of inflammation, and elevated levels have been associated with future risk of cardiovascular events. To explore the role and relationship of CRP and coronary stenosis in the development of unstable angina (UA), plasma levels of CRP were determined on admission in 45 patients with UA, and in 42 patients with stable angina (SA) using high-sensitivity ELISA. Coronary angiography was performed in all patients with coronary heart disease (CHD), and severity of coronary stenosis was evaluated by a quantitative analysis. Lipid measurement was performed using automatic biochemical analyzer. Data available from patients with CHD were compared with those of 41 control subjects. The results showed that plasma levels of CRP are significantly higher in patients with UA than those in patients with SA and control subjects (5.1 +/- 1.4 mg/L vs 1.7 +/- 0.4 mg/L and 1.3 +/- 0.2 mg/L, p<0.01, respectively) with no difference between the latter two groups (p>0.05); the total incidence of clinical events during in-hospital follow-up was higher in the group A (p<0.01); the scores of coronary stenosis are significantly higher in patients with SA than those in patients with UA (4.9 +/- 2.1 vs 3.4 +/- 1.4, p<0.05); there is no correlation between plasma levels of CRP and serum total cholesterol (TC) as well as high-density lipoprotein cholesterol (HDL-C) in both groups (p>0.05 respectively); there was no correlation between plasma levels of CRP and severity of coronary stenosis was found in patients with UA (p>0.05) but a significant positive association in patients with SA (p<0.001); and the patients with persistent, severe, treatment-unresponsive UA had significantly higher CRP levels as well as incidence of clinical events than patients with treatment-responsive UA (7.4 +/- 1.8 mg/L vs 2.6 +/- 1.3 mg/L, p<0.01; 0 vs 22.2%, p<0.05). The present data suggested that inflammation may play an important role in the pathogenesis of UA, and the plasma levels of CRP might have a higher prognostic value than the severity of coronary stenosis correlated with the clinical outcome of instability despite of lipid profile status.

Adult↗