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Biomedical subjects

H Shen

Publications and source records attributed to H Shen.

At least 217 records · Page 12Linked to original sources
PubMed1998

Pharyngeal cross-sectional area and pharyngeal compliance in normal males and females.

Obstructive sleep apnea syndrome is ascribed to pharyngeal dysfunction, but there are only a few reports about the normal morphological values in this anatomical region. We measured the pharyngeal cross-sectional area and the compliance (collapsibility), using the acoustic reflection technique with air breathing, in 181 healthy subjects (age 21-69 years). We assessed their sex-related differences, and the effects of age, body size and body postures on these parameters. The pharyngeal cross-sectional area, defined as the region from the fauces to the glottis, posturally changed with successive decreases in the sitting, left lateral decubitus and supine positions. The area was significantly greater in male than in female subjects in the sitting position (p < 0.01), but no difference was present in the recumbent positions. The pharyngeal cross-sectional area did not correlate with either age or body size. The specific pharyngeal compliance was greater in the males than in the females (p < 0.01) and increased with age only in the male subjects.

Adult↗
PubMed1998

Lifetime and twelve-month prevalence rates of major depressive episodes and dysthymia among Chinese Americans in Los Angeles.

OBJECTIVE: The authors' goal was to estimate the lifetime and 12-month rates of major depressive episodes and dysthymia for Chinese Americans who reside in Los Angeles. This effort, the Chinese American Psychiatric Epidemiological Study, is the first large-scale community psychiatric epidemiological study on an Asian American ethnic group that used DSM-III-R criteria for major depressive episodes and dysthymia. METHOD: A multi-stage sampling design was used to select respondents for participation in the survey. The sample included 1,747 adults, 18-65 years of age, who resided in Los Angeles County and who spoke English, Mandarin, or Cantonese. RESULTS: Approximately 6.9% of the respondents had experienced an episode of major depression and 5.2% had had dysthymia in their lifetime. The 12-month rates of depressive episode and dysthymia were 3.4% and 0.9%, respectively. The most consistent correlate of lifetime and 12-month depressive episode and dysthymia was social stress, measured by past traumatic events and recent negative life events. CONCLUSIONS: The Chinese American Psychiatric Epidemiological Study provides a rare opportunity to investigate the heterogeneity within a single Asian American ethnic group, Chinese Americans, and to identify the subgroups among Chinese Americans who may be most at risk for mental health problems.

Acculturation↗
PubMed1998

Reduced lymphoblast neopterin detects GTP cyclohydrolase dysfunction in dopa-responsive dystonia.

OBJECTIVE: To demonstrate that measurement of endogenous neopterin levels in unstimulated lymphoblasts identifies inherited GTP cyclohydrolase 1 (GCH1) dysfunction and can be a diagnostic test for dopa-responsive dystonia (DRD). BACKGROUND: DRD results from decreased dopamine biosynthesis due to dysfunctional GCH1. GCH1 is the rate-limiting enzyme in the biosynthesis of tetrahydrobiopterin (BH4), an essential cofactor for catecholamine synthesis. Mutations in the GCH1 coding region are identified in 60 to 70% of DRD cases; in others, the cause of GCH1 dysfunction is unknown. METHODS: Using HPLC, we measured endogenous neopterin, the main byproduct of the GCH1 reaction, in lymphoblasts under basal conditions and following GCH1 stimulation conditions. RESULTS: In a four-generation family, all identified carriers of dysfunctional GCH1 had basal neopterin levels that were below those of controls. The spouse of one carrier had a mutation in exon 6 of GCH1. Although this man's GCH1 function appeared unaffected by this, his daughter, who was a compound heterozygote with her mother's dysfunctional GCH1 and this mutation, had a phenotype that was more severe than that of typical DRD. Cytokine or phytohemagglutinin (PHA) did not induce GCH1 activity in any carrier of dysfunctional GCH1; controls who did not respond to PHA had increased neopterin levels following cytokine induction. CONCLUSIONS: Endogenous neopterin measurement in unstimulated lymphoblasts is an accurate tool to identify dysfunctional GCH1 and a potential specific diagnostic marker for dysfunctional GCH1 in DRD and other neurologic disorders. Not all mutations in GCH1 affect GCH1 enzyme activity. PHA induction alone, previously used by others, may result in incorrect identification of GCH1 dysfunction in DRD.

Adult↗
PubMed1998

Health insurance coverage among Chinese Americans in Los Angeles County.

OBJECTIVES: This paper examines the factors associated with health insurance coverage among Chinese Americans in Los Angeles County. METHODS: Data were obtained through interviews conducted in 1993 and 1994 with Chinese Americans (aged 18 through 65 years) residing in Los Angeles County. A multistage probability sample was used to select respondents. RESULTS: The final sample consisted of 1747 respondents, which represented an 82% response rate. Thirty-nine percent of the respondents in the survey were without health insurance at the time of the survey. CONCLUSIONS: Logistic regression analysis showed that marital status, length of residence in the United States, education, employment, and household income were associated with health insurance coverage among Chinese Americans.

Adolescent↗
PubMed1998

[Hepatotoxicity and formation of reactive oxygen species induced by microcystis aeruginosa toxin].

OBJECTIVE: To study hepatotoxicity of Microsystis aeruginosa toxin (microcystin) and its prevention. METHODS: Cytotoxicity and the formation of reactive oxygen species (ROS) of microcystin extracted water bloom were studied in rat liver cells of primary culture. RESULTS: It was found that the release of lactic dehydrogenase (LDH) increased with a time- and dose-dependent pattern in the liver cells treated with microcystin, and a time- dependent formation of ROS also increased simultaneously. The antioxidant, desferrioxamine, could decrease the release of LDH and the formation of ROS in the liver cells treated with microcystin. CONCLUSION: Microcystin has obvious hepatotoxicity and the formation of ROS may play a certain role in its toxic effect on the rat liver cells.

Animals↗
PubMed1998

[A preliminary study on the induction of metallothionein in rats with aluminum administration by different ways].

OBJECTIVE: To study the inductive effects of aluminum (Al) on metallothioneine (MT) in rats. METHODS: Inductive experiment of MT was conducted with Al administration in 16 SD rats, divided into trial and control groups, for two weeks by subcutaneous injection and gastric tube. RESULTS: Al could induce liver MT in the rats, to certain extent, especially more significantly by subcutaneous injection than by oral administration of Al. Oral administration of Al also could induce MT in the small intestine. Induction of MT by Al reflected the body response to stress, the metal poison Al. CONCLUSION: It postulated that combination of Al with MT was unstable due to its chemical property, so, its detoxication effect was uncertain. In addition, induction of MT in different sites, such as liver and small intestine, by Al could influence the normal metabolism of metal elements, such as zinc, etc.

Aluminum↗
PubMed1998

Expression of human interleukin 12 (hIL-12) in insect cells.

Human interleukin-12(hIL-12) is a herterodimer cytokine, which consists of two disulfide-linked subunits, p40 and p35. This paper reports the expression of hIL-12 using the Baculovirus Expression System in insect cells. First, we constructed two expression vectors pVL1392-hp40 and pVL1393-hp35, and then they were used to co-transfect the insect cells (Sf9) separately with linearized polyhedrosis virus genomic DNA. Two kinds of recombinant viruses AcNPV-hp40 and AcNPV-hp35 were visually screened out. Biological activity of the recombinant hIL-12 (rhIL-12) was detected in the conditioned medium using proliferation assay of PHA-activated human lymphocytes and the expression level was about 1.5 approximately 2 microg/10(6) cells. The results of real-time Biomolecular Interaction Analysis (BIA) and Northern blot demonstrated that the subunits of rhIL-12, hp35, and hp40 were expressed successfully in the insect cells. The apparent molecular weights of rhIL-12 and hp40 homodimer were 76 kDa and 92 kDa under non-reducing conditions of Western blot, respectively. The recombinant hp40 can significantly inhibit the biological activity of hIL-12.

Animals↗
PubMed1998

[A survey of prostate symptoms in old male population].

To know well the prostate symptoms in old men, the prostate symptom scores of 412 male residents over 60 years of age in Chengdu area (116 in city and 296 in countryside) were investigated by using I-PSS. The results showed that there was a significant difference between the city and countryside in terms of symptoms score(P < 0.05) and quality of life scores (P < 0.05). No significant difference was noted among the three age groups (P > 0.05). However, the mean score and the percentage of high score section in the elder group were higher than those in the younger group. The prevalence of benign prostate hypertrophy (BPH) and the demands on quality of life in city were different from those in countryside, and the prevalence rate of BPH increased with age.

Aged↗
PubMed1998

[Effect of vasectomy on apoptosis in spermatogenic cells of the male rat].

To explore the effect of vasectomy on apoptosis of spermatogenic cells, we have detected apoptosis in the testis of vasectomized and sham-operated adult rats within a period of 12 postoperative weeks by means of flow cytometry and TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuride triphosphate nick-end labeling) method. Flow cytometry found that, in vasectomized rat, the sub-haploid peak was higher and the percentage of cells with sub-haploid was increased. The total number of positive TUNEL cells in the vasectomized group was greater than that in the sham-operated group (P < 0.001). Compared with the same time-phased sham-operated subgroups, the number of apoptotic spermatogonia and primary spermatocytes in the testes of the subgroups 2 weeks, 6 weeks and 10 weeks after vasectomy as well as the number of spermatogonia of the subgroup 12 weeks after vasectomy were significantly higher (P < 0.05). These findings demonstrate that vasectomy could enhance the apoptosis of spermatogenic cells.

Animals↗
PubMed1998

The purification and identification of heme oxygenase isoforms from spleen tissue of rat and the expression of heme oxygenase-1 cDNA in COS-1 cells.

OBJECTIVE: To demonstrate that heme oxygenase (HO) isoforms exist in rat spleen treated with hematin and phenylhydrazine and to confirm that the isolated cDNA actually encodes HO-1 by expressing cDNA in monkey kidney cells (COS-1 cells) in order to prepare HO-1 mutant for inhibiting the natural enzyme. METHODS: The rat spleen microsomal fractions were first purified by diethylaminoethyl (DEAE)-Sephacel and hydroxylapatite. The activity of two isoforms (HO-1 and HO-2) of enzyme and their apparent molecular weight on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (SDS-PAGE) were measured. Secondly, using the isolated HO-1 cDNA clone, the expression plasmid pcDNA3HO1 was constructed and transfected into cultured COS-1 cells. The transfected cells were collected and disrupted by sonication, and the microsomes were prepared by ultracentrifugation. The activity of HO-1 was measured. RESULTS: Two isoforms were purified and identified in treated rat spleen and HO-1 was the predominant form. The ratio of HO-1 to HO-2 was 3.2:1. The apparent molecular weights of HO-1 and HO-2 were about 30 kD and 36 kD under reducing conditions, respectively. The HO-1 was highly expressed in endoplasmic reticulum of transfected cells. The specific band was located in molecular weight of 30 kD. The specific activity was five times higher than that of the control. CONCLUSION: The activity of expressed HO-1 in COS-1 cells is higher than that of purified enzyme from rat spleen tissue. It is suggested that this clone having an insert of 1030 base-pairs encodes HO-1 and that we can prepare HO-1 mutant by site-directed mutagenesis of HO-1 cDNA to prevent and treat hyperbilirubinemia.

Animals↗
PubMed1998

[Clinical study of weishu capsule in treating precancerous lesions of chronic atrophic gastritis].

OBJECTIVE: To explore the therapeutic effect and mechanism of Weishu capsule (WSC) in treating precancerous lesions of chronic atrophic gastritis (CAG). METHODS: Seventy-five cases of precancerous lesions of CAG were distributed to two groups randomly, the treated group (45 patients) treated with WSC by taken orally and the control group (30 patients) treated with Weining granule (WNG) orally. The treatment course of both groups were 6 months. The clinical and pathological effects and the changes in scores of atrophy, intestinal metaplasia and its subgroups, dysplasia, carcinoembryonic antigen (CEA) and proliferating cell nuclear antigen (PCNA) expression were observed before and after treatment. RESULTS: The total effective rate was 91% and the effective rate of atrophy, intestinal metaplasia, dysplasia in the treated group were 64%, 67% and 65% respectively, and the respective scores were lowered significantly after treatment. Compared with the control group the difference between the two groups was statistically significant (P < 0.01, P < 0.05). Immunohistochemical test showed that WSC could inhibit the subgroups of intestinal metaplasia, CEA and PCNA expression significantly (P < 0.01). CONCLUSION: WSC could significantly improve the clinical and pathological changes in the precancerous lesions of CAG. The mechanism might be related to the inducing and promoting effect of WSC on the differentiation and maturity of intestinal metaplasia cells and dysplasia cells. WSC could also inhibit and correct the abnormal proliferation of cells.

Adult↗
PubMed1998

[Effects of clinorotation on cytosolic free calcium level in embryonic chick brain cells].

Cytosolic free Ca2+ ([Ca2+]i) in suspended brain cells of chicken embryos hatched for 6-18 d (E6-E18) was measured by using the fura-2/AM fluorescence spectroscopy. The biological effects of microgravity on the embryonic chicks were simulated by revolving on a clinostat during their hatch. The experimental results showed that level of [Ca2+]i in E8-E17 embryonic brain cells decreased after revolving for different period. [Ca2+]i in brain cells of E10 and E13 chick embryos reduced significantly (P < 0.01) after revolving 4-7 h and 24 h respectively. When E10 and E13 chick embryos were incubated again as long as being revolved, [Ca2+]i in brain cells rose but were still lower than the controls. The levels of cytosolic free calcium in brain cells of revolved E17 embryonic chicks increased after being colorpunctured by red light. These results demonstrate that the decrease of [Ca2+]i in embryonic chick brain cells caused by clinorotation is reversible, and colorpuncture can accelerate this recovery.

Animals↗
PubMed1998

[Biosynthesis of a single peptide chain containing human chorionic gonadotropin beta and ovine common alpha subunits tandem].

hCG beta-oLH alpha chimeric cDNA was constructed by using overlapping PCR to contact the codons of C-terminal end of hCG beta with the codons of N-terminal end of oLH alpha, then it was subcloned into nuclear polyhedrosis virus (AcNPV) expression vector pVL1393 to construct expression vector pVL1393-hCG beta-oLH alpha. The insect cells (Sf9) were cotransfected by the expression vector pVL1393-hCG beta-oLH alpha and BaculoGold AcNPV linearized genomic DNA, and recombinant viruses AcNPV-hCG beta-oLH alpha were screened out by plaque assay. Further the insect cells were infected by the recombinant viruses, the recombinant hCG beta-oLH alpha was purified by immunoaffinity chromatography column coupling anti-hCG beta monoclonal antibody from the conditioned media of infected cells. The results of SDS-PAGE silver staining and western blotting showed that hCG beta-oLH alpha single peptide chain had apparent molecular weights of 40.5 kD and 38.0 kD under non-reducing and reducing conditions respectively, indicating the occurrence of disulfide bonds and significant tertiary structure in the single peptide chain. From the results of competitive inhibition of 125I-hCG beta binding we can conclude that the anti-hCG beta antibody-binding activity of hCG beta-oLH alpha chimera is lower than that of native hCG, but higher than that of native hCG beta. Therefore, we assume that the hCG beta-oLH alpha chimera should have potential application as a target antigen of anti-hCG fertility regulatory vaccine.

Animals↗
PubMed1998

[Expression of murine interleukin 12(mIL-12) in insect cells].

Since human IL-12 is species-specific in its functions and elicits little biological responses from mouse lymphocytes, it is necessary to express recombinant murine IL-12 for the usage in studying the effects of this cytokine in various rodent models. Thereby, we can investigate the role of IL-12 in immune response in vivo and evaluate its potential clinical utility. Thus, we firstly constructed two expression vectors, pVL1393-mp40 and pVL1393-mp35. They were used to co-transfect the insect cells(Sf9) separately with linearized polyhedrosis virus genomic DNA. Two kinds of recombinant viruses AcNPV-mp40 and AcNPV-mp35 were visually screened out, and mp40 and mp35 were co-expressed in the insect cells co-infected by AcNPV-mp40 and AcNPV-mp35. The results of real-time Biomolecular Interaction Analysis (BIA) and Northern blot demonstrated that the recombinant mIL-12 was expressed successfully in the insect cells. The molecular weights of recombinant mp40 and mp35 were 40 KDa and 22 KDa on SDS-PAGE under reducing conditions, respectively. The apparent molecular weight of recombinant mIL-12 is 80 KDa under non-reducing conditions of Western blot. Biological activity of the recombinant product was detected in conditional medium using antibody-capture bioassay. The expression level of recombinant mIL-12 was about 10-15 micrograms/10(6) cells, as compared with the calibration curve of mIL-12.

Animals↗
PubMed1998

[Host-guest molecule interaction mechanism of hemostatics with liposomes and red blood cells studied with fluorescence polarimetric method].

The supermolecule compounds of adrenobazone, p-aminomethylbenzoic acid, vitamin K1, 6-amino caproic acid with liposomes and red blood cells were studied by fluorescence polarimetric method. The mechanisms of formation of the supermolecule compounds were examined by fluorescence probe of the link of 1,6-dipheny-1,3,5-hexatriene (DPH) with liposomes which were taken as a model of blood cells. The interaction mechanism of hemostatics with red blood cells was described according the quantitative relationship between polarization value (P) and the microviscosity [formula: see text]. The result showed that the acting force between hemostatics and liposomes or that between hemostatics and red blood cells were mainly supermolecular acting force. The acting force between vitamin K1 and cytomembrane is hydrophobic force and those between adrenobazone, p-aminomethylbenzoic acid, or 6-amino caproic acid and cytomembrane are hydrogen bond or electrostatic force. Under the same drug concentration, all of the four haemostatics can reduce the fluidity of the cell membrane, which benefits blood coagulation. The binding ways of hemostatics with red blood cells was also discussed.

4-Aminobenzoic Acid↗
PubMed1998

[Study on HCMV replication in gene transtecfed cells].

Five gene transfected cells (GTC: A5, B3, D3, G8 and H3) were generated by DNA (from HEP-2) transfer (into HEL). Chromosome number of the transfectants fell between that of HEL and the combined chromosome number of the two cell lines. D3 showed more positive fluorescence cells than A5, B3, G8 and H3 by 4d after infection of HCMV. As HCMV infection dose was increased from 0.1 to 100 PFU/ml, significant increase of viral production was observed. The similar susceptibility to HCMV was shown in different passages of D3. The immortal D3 may provide a tool to analyze host cell factors controlling the transcription and replication of HCMV.

Cell Line↗
PubMed1998

[Analysis of rhodopsin and peripherin/RDS genes in Chinese patients with retinitis pigmentosa].

PURPOSE: To disclose the mutation of rhodopsin and peripherin/RDS genes among Chinese patients with retinitis pigmentosa as there was no identified mutation through sequencing reported in Chinese. METHODS: Genomic DNA was prepared from the peripheral lymphocytes. Gene fragments of the rhodopsin and peripherin/RDS genes were amplified by the polymerase chain reaction. The PCR products were analyzed by Heteroduplex-SSCP technique. PCR samples with aberrant migrational bands were identified through direct sequencing or cloning sequencing. RESULTS: Three different mutations in the rhodopsin gene were found in 3 of the 83 patients with retinitis pigmentosa(Va1104Phe, Lys311Glu, Pro347Leu). Two of the three mutations have not been reported before. One of the two (heterozygous, Va1104Phe) was found in an isolated patient and the other (homozygous, Lys311Glu) in a family with autosomal recessive retinitis pigmentosa. Mutation of peripherin/RDS gene was not found in the 83 patients. CONCLUSION: Mutation in the rhodopsin gene is the common cause in Chinese patients with retinitis pigmentosa, either autosomal dominant, recessive or sporadic.

Base Sequence↗