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Biomedical subjects

H Jin

Publications and source records attributed to H Jin.

At least 55 records · Page 3Linked to original sources
PubMed2001

[A comparative study on the sensitivity and specificity of cholinesterase and glutathione s-transferase in Gammarus pulex L].

Studies on the influences of lindane, pirimiphos methyl, permethrin, zinc and dodecyl linear alkybenzene sulfonate (LAS) on the activity and toxicity of cholinesterase (ChE) and glutathione s-transferase (GST) in Gammarus pulex L. showed that only pirimiphos methyl caused a change in ChE activity in Gammarus, with a significant reduction in enzyme activity after 24 h and 48 h exposure. Both lindane and permethrin caused a change in GST activity in Gammarus, with a significant increase in enzyme activity after 48 h exposure. Lindane alos caused a significant increase in GST activity after 24 h exposure. Biomarkers ChE and GST were demonstrated a high degree of specificity and sensitivity in comparison to the lethality assay, but GST activity was less specific than ChE activity.

Animals↗
PubMed2001

[Identification of key toxicants in a bleaching effluent--a case study].

The toxicity identification evaluation (TIE) was conducted with a toxic bleaching effluent to identify its toxic components. Toxicity characterisation procedures (phase I) indicated that the primary toxicants in the effluent were volatile, and could be reduced by sodium thiosulfate. Toxicity-based fractionation techniques (phase II) were conducted, and the oxidation organic chloridates were found not to be the major toxicants. Deletion approach of phase III confirmed that the toxicity decreased with the decrease of free and total residual chlorine concentrations, indicating that Cl2, HClO and ClO- were identified as primary toxicants in the effluent.

Chlorine↗
PubMed2001

Relationship between gene polymorphism of the PAI-1 promoter and myocardial infarction.

OBJECTIVE: To investigate the association between gene polymorphism of the plasminogen activator inhibitor-1 (PAI-1) and myocardial infarction (MI) in Chinese. METHODS: PAI-1 genotyping with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele specific polymerase chain reaction (ASPCR) was performed in 87 myocardial infarction patients and 92 unrelated healthy controls. All subjects' clinical features and PAI-1 activity were tested. RESULTS: There were two polymorphisms within the promoter, a G/A single base substitution polymorphism upstream at -844 bp, and a single guanosine deletion/insertion 4G/5G polymorphism -675 bp upstream from the start of transcription. Significant differences between the patients and the controls were observed neither for the frequencies of the GG, GA and AA genotypes nor for the PAI-1 activities of these three types. But for the 4G/5G polymorphism, there were significant differences between patients and controls for the frequencies of the 4G/4G, 4G/5G and 5G/5G genotypes (P < 0.05). In the MI group, the PAI-1 activity of the 4G/4G type was significantly higher than that of the 5G/5G type (P < 0.05). Further more, a positive correlation between the glucose level and PAI-1 activity was found (r = 0.34, P = 0.02). CONCLUSION: This study indicates that the 4G/5G gene polymorphism of PAI-1 is associated with myocardial infarction, that 4G/4G type is probably an important hereditary risk factor, and that glucose has functional importance in regulating PAI-1 activity.

Adult↗
PubMed2001

[p15 gene expression in acute lymphoblastic leukemia cell line Molt4 induced by arsenic trioxide].

OBJECTIVE: To explore the correlation between arsenic trioxide and gene methylation in an acute lymphoblastic cell line. METHODS: Methylation of p15 gene in Molt4 cell line was detected by polymerase chain reaction (PCR) using methylation specific primer (MSP) and the expression of this gene after arsenic trioxide treatment was detected by reverse transcriptase PCR (RT-PCR). The cell cycle and cell growth curve were also observed by flow cytometry. RESULTS: p15 gene failed to express in molt4 after methylation. The expression was recovered, cell growth was inhibited, and G(1) cell cycle arrest was observed, when the cells exposed to arsenic. CONCLUSION: Arsenic trioxide could activate the expression of p15 gene and reverse cell cycle negative regulation.

Acute Disease↗
PubMed2001

[Study on the organic acids metabolism in Candida glycerolgenesis under different fermentation conditions].

The organic acids in Candida glycerolgenesis fermentation medium affected both the glycerol yield and quality. When other fermentation condition was constant, the total acidity in medium increased when the volumetric ratio of medium to flask and corn steep liquid concentration were increased. When the volumetric ratio of medium to flask was 0.20 and the corn steep liquid concentration was 8 g/L, there have high yield of pyruvate and lactate produced at growth phase, 4.1 g/L and 1.0 g/L, respectively, which are two times than control sample at usual fermentation condition, hence, the glycerol yield was lower. However, the volumetric ratio of medium to flask was 0.08 and the corn steep liquid concentration was 4 g/L, the yield of pyruvate and lactate were lower and the glycerol yield was higher, but the acetate could be accumulated to 2.6 g/L. The organic acids also could be metabolized in final fermentation process, such as the initial glucose concentration was 100 g/L, after the glucose was completely utilized, both the glycerol and organic acids concentration decreased, and pyruvate or lactate could be converted to acetate in following fermentation process. In addition, the additive also can change the production of organic acids, with the addition of 1% oleic acid or VB1 the acetate concentration could be decreased and increased the production of pyruvate, hence, improved the yield of glycerol. While the fluoro-pyruvate or sulphite were added in medium, the acetate was increased largely and ketoglutarate was decreased accordingly, also increase the glycerol yields about 20%.

Acetates↗
PubMed2001

[Speech discrimination with bilateral cochlear implants in noisy conditions].

OBJECTIVE: To investigate the speech discrimination abilities of patients with bilateral cochlear implants. METHODS: The speech discrimination scores of Cantonese lexical tones were compared between two patients with unilateral and bilateral cochlear implants at different signal to noise (S/N) ratios. RESULTS: At favorable listening conditions with S/N ratios of +15, +10, and the mean binaural speech discrimination scores were 96%, 92% and 88%, but the mean monaural speech discrimination scores from the left and right ear were 86%, 83% and 74% respectively. At unfavorable listening conditions with adverse S/N ratios of 0, -5, -10 and -15, almost no speech discrimination scores could be obtained from monaural hearing but 80%, 72%, 68% and 54% respectively from binaural stimulation. CONCLUSION: Bilateral cochlear implants improve the discrimination of Cantonese lexical tones better than unilateral cochlear implant at various S/N ratios This study confirms the benefits of binaural hearing even in patients using bilateral cochlear implants.

Adult↗
PubMed2001

Flashlamp-pumped pulsed dye laser in treatment of port-wine stains.

OBJECTIVE: To assess the effectiveness of the flashlamp-pumped pulsed dye laser (Photogeneca V, Synosure Corp, Boston, United States) in the treatment of port-wine stains. METHODS: One hundred and ninety-four consecutive patients with port-wine stains were treated with a flashlamp-pumped pulsed dye laser in Peking Union Medical College Hospital from January 1998 to August 1999. RESULTS: Of 194 patients who completed treatment, 56.2% had more than 60% fading of the lesion and only 6.7% had less than 20% fading. An average of 3.6 treatments were needed to achieve more than 60% fading. The response was better in children than in adults, although the difference was not significant. Pigmentary change (usually transient) occurred in 3.1% of patients. CONCLUSIONS: This study confirms the efficacy of the flashlamp-pumped pulsed dye laser in the treatment of port-wine stains in children and adults.

Adolescent↗
PubMed2001

[A comparison of lanthanum contained rinse on acid resistant abilities to human enamel and root surface].

OBJECTIVE: To compare the effect of different does of lanthanum-contained rinse solution on carious-resistance, and to investigate the acid-resistant abilities of dental enamel and root surface that treated with lanthanum-contained rinse solution. METHODS: Human dental root surfaces were treated in vitro with various doses (100 x 10(-6) - 2000 x 10(-6)) of lanthanum-contained rinse solution under the pH cycle environment that mimic the normal pH change curve of oral cavity. The qualitative and quantitative analysis was carried out on dental cementum according to their mineralized degrees. The best effective dose for carious-resistance was set for further investigation in vitro. Dental enamel and root surfaces were treated with the rinse for 1 hour each day, total for five days. RESULTS: The rinse solution containing 500 x 10(-6) lanthanum or more than it showed a obvious carious-resistant effect and there was no significant difference between root surfaces and dental enamel while treated with 500 x 10(-6) lanthanum-contained rinse solution. To compare demineralized degrees between enamel and root surfaces before or after treatment, enamel showed severer demineralization than root surfaces. CONCLUSION: 500 x 10(-6) lanthanum-contained rinse solution is considered to be the lowest effective dose for carious-resistance, and lanthanum-contained rinse solution is especially suitable for the treatment and prevention of dental root caries.

English Abstract↗
PubMed2001

[Observation of the effectiveness of APFI gel to prevent dental caries].

OBJECTIVE: To observe the effectiveness of APFI Gel applied to pupils to prevent dental caries. METHODS: 2918 cases of 6 to 13 years old pupils from four urban and countryside primary schools were randomly divided into two groups,the experiment group and the control group. By theirs different school and classes and groups, APFI Gel was used to 2 160 cases of the experimental group to prevent dental caries. The control group consisted of 758 cases. The incidence of dental caries of the two groups were observed in the same time and using the same way. RESULTS: Statistical analysis indicated that the incidence of dental caries in the experimental group decreased by 52.3%,the newly increased DMFT decreased by 60.14% (P<0.01). The incidence of dental caries of the first molar decreased by 52.43%,the newly increased DMFT decreased by 65.52% (P<0.01). CONCLUSION: It is effective to use APFI Gel to prevent caries.

English Abstract↗
PubMed2001

[Detection of genital tract cytomegalovirus and Chlamydia trachomatis infection in patients with tubal pregnancy].

OBJECTIVE: To investigate the influence of genital tract cytomegalovirus and chlamydia infection on the incidence of tubal pregnancy. METHODS: Ninety-five women with tubal pregnancy (study group) and 42 women with ovarian cysts (control group) were selected for this study. Serum cytomegalovirus (CMV) IgM was identified by enzyme-link-immunosorbent-assay (ELISA). Cervical secretions, endometrium, and salpinx tissue were tested for CMV gH gene and chlamydia heat shock protein (HSP) gene by nest polymerase chain reaction (PCR) and PCR respectively. RESULTS: CMV IgM was positive in 14 (15%) women with tubal pregnancy, and 1 (2%) in the control group. CMV gH gene was detected in 18 women (19%) and chlamydia HSP gene in 25 (26%) of the tubal pregnancy group, and 2 (5%) and 2 (5%) in the control group respectively. There were significant differences between the study and the control group (P < 0.05) with respect to detection of CMV IgM, CMV gH gene and chlamydia HSP gene. CONCLUSIONS: CMVand chlamydia trachomatis genital tract infection were more common in women with tubal pregnancy than that in the control group. Genital CMV and chlamydia trachomatis infection may associate with an increased incidence of tubal pregnancy.

Antibodies, Viral↗
PubMed2000

Polyhydroxylated C(60), fullerenols, as glutamate receptor antagonists and neuroprotective agents.

Derivatives of C(60) have been shown to be effective free radical scavengers. Hence, many of the biological functions of fullerene are believed to be due to their antioxidant properties. Here we present evidence to show that fullerenols, that are caged fullerene oxides, exert their neuroprotective functions by blocking glutamate receptors and lowering the intracellular calcium, [Ca(2+)](i). In neuronal cultures, fullerenols reduce glutamate-induced neurotoxicity by about 80% at 50microM. No significant effect was observed on H(2)O(2)/Fe(2+)-induced neurotoxicity under the same conditions. Fullerenols were found to inhibit glutamate receptor binding in a dose-dependent manner inhibiting 50% of glutamate binding at 50 microM. Furthermore, AMPA receptors were found to be more sensitive to fullerenols than NMDA and KA receptors. On the other hand, GABA(A) receptors and taurine receptors were not significantly affected by fullerenols at the same concentrations used, suggesting that fullerenols inhibit primarily the glutamate receptors. In addition, fullerenols were also found to lower glutamate (Glu) receptor-induced elevation of [Ca(2+)](i), suggesting that the underlying mechanism of neuronal protective function of fullerenols is likely due to its ability to block the glutamate receptors and to reduce the level of [Ca(2+)](i).

Animals↗
PubMed2000

Transcriptional repression by AtMYB4 controls production of UV-protecting sunscreens in Arabidopsis.

An Arabidopsis thaliana line that is mutant for the R2R3 MYB gene, AtMYB4, shows enhanced levels of sinapate esters in its leaves. The mutant line is more tolerant of UV-B irradiation than wild type. The increase in sinapate ester accumulation in the mutant is associated with an enhanced expression of the gene encoding cinnamate 4-hydroxylase, which appears to be the principal target of AtMYB4 and an effective rate limiting step in the synthesis of sinapate ester sunscreens. AtMYB4 expression is downregulated by exposure to UV-B light, indicating that derepression is an important mechanism for acclimation to UV-B in A.thaliana. The response of target genes to AtMYB4 repression is dose dependent, a feature that operates under physiological conditions to reinforce the silencing effect of AtMYB4 at high activity. AtMYB4 works as a repressor of target gene expression and includes a repression domain. It belongs to a novel group of plant R2R3 MYB proteins involved in transcriptional silencing. The balance between MYB activators and repressors on common target promoters may provide extra flexibility in transcriptional control.

Arabidopsis↗
PubMed2000

The synthesis and SAR of rhodanines as novel class C beta-lactamase inhibitors.

Beta-lactam antibiotics such as the cephalosporins and penicillins have diminished clinical effectiveness due to the hydrolytic activity of diverse beta-lactamases, especially those in molecular classes A and C. A structure activity relationship (SAR) study of a high-throughput screening lead resulted in the discovery of a potent and selective non-beta-lactam inhibitor of class C beta-lactamases.

Drug Evaluation, Preclinical↗
PubMed2000

Recombinant respiratory syncytial viruses with deletions in the NS1, NS2, SH, and M2-2 genes are attenuated in vitro and in vivo.

Respiratory syncytial virus (RSV) encodes several proteins that lack well-defined functions; these include NS1, NS2, SH, and M2-2. Previous work has demonstrated that NS2, SH, and M2-2 can each be deleted from RSV genome and thus are considered as accessory proteins. To determine whether RSV can replicate efficiently when two or more transcriptional units are deleted, we removed NS1, NS2, SH, and M2-2 genes individually and in different combinations from an infectious cDNA clone derived from human RSV A2 strain. The following six mutants with two or more genes deleted were obtained: DeltaNS1NS2, DeltaM2-2SH, DeltaM2-2NS2, DeltaSHNS1, DeltaSHNS2, and DeltaSHNS1NS2. Deletion of M2-2 together with NS1 was detrimental to RSV replication. It was not possible to obtain a recombinant RSV when all four genes were deleted. All of the double and triple deletion mutants exhibited reduced replication and small plaque morphology in vitro. Replication of these deletion mutants was more reduced in HEp-2 cells than in Vero cells. Among the 10 single and multiple gene deletion mutants obtained, DeltaM2-2NS2 was most attenuated. DeltaM2-2NS2 formed barely visible plaques in HEp-2 cells and had a reduction of titer of 3 log(10) compared with the wild-type recombinant RSV in infected HEp-2 cells. When inoculated intranasally into cotton rats, all of the deletion mutants were attenuated in the respiratory tract. Our data indicated that the NS1, NS2, SH, and M2-2 proteins, although dispensable for virus replication in vitro, provide auxiliary functions for efficient RSV replication.

Animals↗
PubMed2000

Association of L-glutamic acid decarboxylase to the 70-kDa heat shock protein as a potential anchoring mechanism to synaptic vesicles.

Recently we have reported that the membrane-associated form of the gamma-aminobutyric acid-synthesizing enzyme, l-glutamate decarboxylase (MGAD), is regulated by the vesicular proton gradient (Hsu, C. C., Thomas, C., Chen, W., Davis, K. M., Foos, T., Chen, J. L., Wu, E., Floor, E., Schloss, J. V., and Wu, J. Y. (1999) J. Biol. Chem. 274, 24366-24371). In this report, several lines of evidence are presented to indicate that l-glutamate decarboxylase (GAD) can become membrane-associated to synaptic vesicles first through complex formation with the heat shock protein 70 family, specifically heat shock cognate 70 (HSC70), followed by interaction with cysteine string protein (CSP), an integral protein of the synaptic vesicle. The first line of evidence comes from purification of MGAD in which HSC70, as identified from amino acid sequencing, co-purified with GAD. Second, in reconstitution studies, HSC70 was found to form complex with GAD(65) as shown by gel mobility shift in non-denaturing gradient gel electrophoresis. Third, in immunoprecipitation studies, again, HSC70 was co-immunoprecipitated with GAD by a GAD(65)-specific monoclonal antibody. Fourth, HSC70 and CSP were co-purified with GAD by specific anti-GAD immunoaffinity columns. Furthermore, studies here suggest that both GAD(65) and GAD(67) are associated with synaptic vesicles along with HSC70 and CSP. Based on these findings, a model is proposed to link anchorage of MGAD to synaptic vesicles in relation to its role in gamma-aminobutyric acid neurotransmission.

Animals↗
PubMed2000

Regulated expression of the rat recombinant P2X(3) receptor in stably transfected CHO-K1 tTA cells.

In this report, the regulatable expression by tetracycline of the rat recombinant P2X(3) receptor in stably transfected Chinese hamster ovary (CHO-K1) expressing the tetracycline-controlled transactivator (tTA) is described. cDNA encoding the rat P2X(3)-receptor was subcloned into pTRE (a tetracycline-repressible expression vector) which was used to transfect stably CHO-K1 tTA cells. Using whole cell patch clamp techniques, 100 microM ATP evoked inward currents of 2.9+/-1.6 nA in transfected cells grown in the absence of tetracycline (tet-). The P2X(3) receptor protein was detectable by immunoblot as early as 24 h and protein expression levels continued to increase as much as 192 h following activation of tTA by the removal of the antibiotic. Saturation binding isotherms using [35S]ATP gamma S yielded a pK(d) of 8.2+/-0.1 and a B(max) of 31.9+/-3.5 pmol/mg protein in tet- cell membranes and a pK(d) of 8.1+/-0.1 and a B(max) of 5.8+/-0.8 pmol/mg protein in tet+ cell membranes. The agonist ligands 2MeSATP and alpha beta MeATP displaced the binding of [35S]ATP gamma S in tet- cell membranes with very high affinity, yielding pIC(50) values of 9.4+/-0.2 and 7.5+/-0. 2, respectively. In tet+ cell membrane, displacement of [35S]ATP gamma S by 2MeSATP and alpha beta MeATP was of much lower affinity (pIC(50) values of 7.8 and 6.2, respectively). ATP, ADP and UTP showed similar displacement of [35S]ATP gamma S binding in tet- and tet+ cell membranes. In other experiments, cytosolic Ca(2+) was monitored using the fluorescent indicator, fluo-3. Increases in cytosolic Ca(2+) were elicited by 100 nM alpha beta MeATP in tet- cells while no increases in cytosolic Ca(2+) were detected below 100 microM alpha beta MeATP in either tet+ cells or untransfected cells. These calcium responses to alpha beta MeATP had a pEC(50) of 6.7 and were transient, returning to baseline within 120 s. Suramin produced concentration-dependent, parallel, dextral shifts of E/[A] curves to alpha beta MeATP yielding a pK(B) of 5.6. PPADS produced non-parallel, dextral shifts of E/[A] curves to alpha beta MeATP which were insurmountable. These results show for the first time, expression of a functional, homomeric recombinant rat P2X(3) receptor which is under regulated expression in a stably transfected mammalian cell line.

Animals↗