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Biomedical subjects

Y He

Publications and source records attributed to Y He.

At least 361 records · Page 20Linked to original sources
PubMed1995

Distribution of medical insurance in China.

This paper investigates factors related to the distribution of medical insurance coverage in China, using information from an eight-province household survey of almost 16,000 individuals, conducted in 1989. Results of bivariate analyses show that medical insurance coverage, defined very broadly, varies considerably by individual and regional characteristics. Age, gender, education, occupation, employment sector, urbanization, level of industrial and commercial development, and province are all related to being insured or not. In addition, we find that the type of insurance program available to people varies by these same factors, and that the benefits provided by the seemingly uniform public and worker programs also vary, especially by province and degree of urban development. When the individual and regional variables are considered together in logistic regression analyses, the factors most strongly statistically related to the likelihood of being insured are where one works and where one lives. The distribution of insurance benefits in China appears to result in a pattern in which the rural and the poor, who are often at great risk of illness, are less likely to have medical insurance.

Adolescent↗
PubMed1995

Role of phospholipase D in the cAMP signal transduction pathway activated during fibroblast contraction of collagen matrices.

Fibroblast contraction of stressed collagen matrices results in activation of a cAMP signal transduction pathway. This pathway involves influx of extracellular Ca2+ ions and increased production of arachidonic acid. We report that within 5 min after initiating contraction, a burst of phosphatidic acid release was detected. Phospholipase D was implicated in production of phosphatidic acid based on observation of a transphosphatidylation reaction in the presence of ethanol that resulted in formation of phosphatidylethanol at the expense of phosphatidic acid. Activation of phospholipase D required extracellular Ca2+ ions and was regulated by protein kinase C. Ethanol treatment of cells also inhibited by 60-70% contraction-dependent release of arachidonic acid and cAMP but had no effect on increased cAMP synthesis after addition of exogenous arachidonic acid or on phospholipase A2 activity measured in cell extracts. Moreover, other treatments that inhibited the burst of phosphatidic acid release after contraction--chelating extracellular Ca2+ or down-regulating protein kinase C--also blocked contraction activated cyclic AMP signaling. These results were consistent with the idea that phosphatidic acid production occurred upstream of arachidonic acid in the contraction-activated cAMP signaling pathway.

Arachidonic Acid↗
PubMed1995

Coamplification of HIV type 1 and beta-globin gene DNA sequences in a nonisotopic polymerase chain reaction assay to control for amplification efficiency.

The polymerase chain reaction (PCR) fails to detect HIV-1 sequences in 5% of infected individuals. To screen for false-negative PCR tests, we developed a nonisotopic PCR assay in which sequences from the beta-globin gene and from the HIV-1 vpu-env region were coamplified with biotinylated and fluorescein-labeled primers, respectively. Coamplified products were reacted with specific internal digoxigenin-labeled RNA probes. Hybrids were detected in a microtiter plate coated with streptavidin or anti-fluorescein antibody, with enzyme-labeled anti-digoxigenin antibody. After the optimization of the coamplification conditions, the assay could detect 5 proviral DNA copies in a lysate from 100,000 peripheral blood mononuclear cells. Fifty-seven samples from 55 HIV-1-seropositive patients and 25 samples from 25 seronegative individuals were evaluated. Fifty-two samples from HIV-infected individuals were positive for HIV-1 vpu-env sequences. Three of the 5 PBMC lysates falsely negative for HIV-1 sequences had reactivities for beta-globin (3-23 fu) below that of 100,000 cells (304 fu). Nonisotopic coamplification allowed for the evaluation of the quality of specimens for PCR concurrently with the detection of the presence of viral template sequences.

Acquired Immunodeficiency Syndrome↗
PubMed1995

P-element mutations affecting embryonic peripheral nervous system development in Drosophila melanogaster.

The Drosophila embryonic peripheral nervous system (PNS) is an excellent model system to study the molecular mechanisms governing neural development. To identify genes controlling PNS development, we screened 2000 lethal P-element insertion strains. The PNS of mutant embryos was examined using the neural specific marker MAb 22C10, and 92 mutant strains were retained for further analysis. Genetic and cytological analysis of these strains shows that 42 mutations affect previously isolated genes that are known to be required for PNS development: longitudinals lacking (19), mastermind (15), numb (4), big brain (2), and spitz (2). The remaining 50 mutations were classified into 29 complementation groups and the P-element insertions were cytologically mapped. The mutants were classified in five major classes on the basis of their phenotype: gain of neurons, loss of neurons, organizational defects, pathfinding defects and morphological defects. Herein we report the preliminary phenotypic characterization of each of these complementation groups as well as the embryonic lacZ expression pattern of each P-element strain. Our analysis indicates that in most of the P-element insertion strains, the lacZ reporter gene is not expressed in the developing PNS.

Animals↗
PubMed1995

Prognostic factors in human immunodeficiency virus-positive patients with a CD4+ lymphocyte count < 50/microL.

This analysis investigated variability of survival time in a cohort of 553 human immunodeficiency virus type 1 (HIV-1)-infected homosexual or bisexual men with < 50 CD4+ cells/microL. Median survival after the first CD4+ cell count < 50/microL was 1.34 years; 25% survived > or = 2 years. Multivariate analysis showed longer survival with concurrent acyclovir and zidovudine use, hemoglobin > or = 12 g/dL, and full-time employment (P < .0001). Other significant covariates associated with longer survival included African-American race, no prior AIDS illness, weight loss < 4.5 kg, and zidovudine use (with or without concurrent acyclovir) after CD4+ cells fell to < 50/microL. An easily derived score identified Multicenter AIDS Cohort Study subjects likely to survive > 2 years after CD4+ cell count was < 50/microL. Survival once CD4+ cell count fell below 50/microL may be longer for persons with a good performance status and specific clinical markers. Health care providers should consider these variables in decision-making strategies and design of clinical trials.

Acyclovir↗
PubMed1995

Inhibition of cell growth by combination of alpha-difluoromethylornithine and an inhibitor of spermine synthase.

The inhibitory effect on cell growth of a combination of alpha-difluoromethylornithine (DFMO) and an inhibitor of aminopropyl transferase was examined. N-(3-aminopropyl)cyclohexylamine (APCHA) and trans-4-methylcyclohexylamine (4MCHA) were used as inhibitors of spermine and spermidine synthases, respectively. Combination of DFMO and APCHA showed strong inhibitory effects on the growth of FM3A cultured cells and P388 leukemia cells in mice, compared with DFMO alone. The prolongation of survival time of P388 leukemia-bearing mice by DFMO (1,500 mg/kg) was 1.12-fold, while that by DFMO (1,500 mg/kg) plus APCHA (25 mg/kg) was 1.30-fold. The prolongation of survival time nearly paralleled the decrease of P388 leukemia cells in mice. However, the antiproliferative effect of DFMO was not strengthened by 4MCHA in the above two experimental systems. In the FM3A cell culture system, both putrescine and spermidine contents were decreased by DFMO, but spermine content did not decrease significantly. When APCHA was added to the medium with DFMO, spermine content was decreased greatly but a compensatory increase in spermidine was observed. Spermidine content in P388 leukemia cells was also decreased by DFMO, the increase in spermine was suppressed but a compensatory increase in spermidine was observed. Nevertheless, the spermidine content remained significantly low compared with the value in non-treated P388 leukemia cells. Thus, the results indicate that the antiproliferative effect of DFMO was strengthened by APCHA due to the decrease in spermine content, and that the decrease in total amount of spermidine and spermine, especially the decrease in spermine, is necessary for inhibition of cell growth.

Animals↗
PubMed1995

Carbon monoxide-induced activation of gene expression in Rhodospirillum rubrum requires the product of cooA, a member of the cyclic AMP receptor protein family of transcriptional regulators.

Induction of the CO-oxidizing system of the photosynthetic bacterium Rhodospirillum rubrum is regulated at the level of gene expression by the presence of CO. In this paper, we describe the identification of a gene that is required for CO-induced gene expression. An 11-kb deletion of the region adjacent to the previously characterized cooFSCTJ region resulted in a mutant unable to synthesize CO dehydrogenase in response to CO and unable to grow utilizing CO as an energy source. A 2.5-kb region that corresponded to a portion of the deleted region complemented this mutant for its CO regulation defect, restoring its ability to grow utilizing CO as an energy source. When the 2.5-kb region was sequenced, one open reading frame, designated cooA, predicted a product showing similarity to members of the cyclic AMP receptor protein (CRP) family of transcriptional regulators. The product, CooA, is 28% identical (51% similar) to CRP and 18% identical (45% similar) to FNR from Escherichia coli. The insertion of a drug resistance cassette into cooA resulted in a mutant that could not grow utilizing CO as an energy source. CooA contains a number of cysteine residues substituted at, or adjacent to, positions that correspond to residues that contact cyclic AMP in the crystal structure of CRP. A model based on this observation is proposed for the recognition of CO by Cooa. Adjacent to cooA are two genes, nadB and nadC, with predicted products similar to proteins in other bacteria that catalyze reactions in the de novo synthesis of NAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1995

Experimental allergic encephalomyelitis in non-human primates: diffusion imaging of acute and chronic brain lesions.

Diffusion imaging and T2-weighted magnetic resonance imaging were performed on 16 monkeys with experimental allergic encephalomyelitis (EAE), a model of the human demyelinating disease MS. The purpose of this study was to determine whether local changes in diffusion image intensity could be correlated with the formation of acute and chronic demyelinating lesions. Diffusion image analysis was restricted to the internal capsule of the brain because of its anatomic orientation of fiber pathways. Acute inflammatory EAE lesions were large and monophasic, as visualized by T2-weighted MRI, and were accompanied by a decrease in the diffusion MR image signal with the diffusion-sensitizing gradient in all three orthogonal directions (n = 27 brain regions, P < 0.005). Chronic demyelinating lesions were preceded by multiple inflammatory attacks, as visualized by MRI, and by a decrease in diffusion MR image signal with the diffusion-sensitizing gradient in the two orthogonal directions perpendicular to the fibers of the internal capsule (n = 18 brain regions, P < 0.005). However, for the chronic group, there was no significant change in the diffusion MR image signal with diffusion-sensitizing gradient parallel to the fibers of the internal capsule at the terminal scan, suggesting little change in the water diffusion within the nerve fibers. These results suggest that diffusion imaging holds promise for measuring subtle changes in water diffusion due to different types of brain damage.

Acute Disease↗
PubMed1995

Modifications of neurofilament proteins by possible metabolites of allyl chloride in vitro.

Chronic exposure to allyl chloride (ALL) is known to produce a central-peripheral distal axonopathy. In relation to the mechanism(s), the present study was conducted to examine the abilities of ALL and its putative metabolites, i.e., epichlorohydrin, glycerol alpha-monochlorohydrin, allyl alcohol and acrolein to cross-link proteins in vitro. Neurofilament-riched cytoskeletal proteins (1mg/ml) and ovalbumin (10mg/ml) were incubated with 160 mM tested chemicals except for acrolein at 0.5 mM and 1 mM. Time-dependent studies by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed that not only ALL, but also acrolein and epichlorohydrin exerted chemical modifications on axonal cytoskeletal proteins; while only acrolein-treated ovalbumin could manifest evidence of polymerization of the protein. Immunoblotting of PAGE-separated proteins confirmed that the high molecular weight proteins on the top of SDS-PAGEs were NF antigen-contained covalent cross-linked materials.

1-Propanol↗
PubMed1995

[Study on the lung targeting gelatin microspheres of streptomycin sulphate].

This paper is reported the technology of lung targeting gelatin microspheres of streptomycin sulphate (SMS). The microspheres were prepared with natural biodegradable gelatin as the load material and castor oil as the oil phase. The experimental conditions were optimized, the mean volume diameter obtained being 9.7 microns and the mean rate of encapsulation 15.69%. The content, shape and size of the microspheres showed no remarkable change after storage at 37 degrees C RH 75% for 3 months. Activation energy of heat decomposition E = 75.86kJ/mol. In vitro, the SMS release rate was found to accord with Higuchi equation with t1/2 = 8.6h. In vivo (rabbits) the gelatin microspheres were proved to be concentrated in the lung.

Animals↗
PubMed1995

[A study on human behavior and socioeconomic factors affecting malaria transmission and control in Qiongzhong, Hainan].

This study was conducted in Heping District of Quiongzhong County, a hyperedemic mountainous area, in August-September 1992. The comparative surveys between the village and state-run farm, Li and Miao nationalities and Han nationality were carried out by using the sociological method together with the epidemiological methods. Gray relational analysis was conducted between the aforementioned 7 socioeconomic human behavioral factors and IFA rates. The result showed that their degrees of relation (r) were in the following order: (1) percentage of persons who had stayed in the mountain overnight (r = 0.8690); (2) percentage of bed net users (r = 0.7990); (3) percentage of households seeking medical service (r = 0.7990); (4) number of mosquito nets per person (r = 0.7867); (5) percentage of householders knowing malaria transmission route (r = 0.7798); (6) percentage of households with tile-roofed houses (r = 0.6767) and (7) income per capita (r = 0.6636). It indicates that staying in the mountain, using bed net and seeking medical service were three discriminating factors affecting local malaria transmission and control. Therefore, it is suggested that carrying out health education, changing the stay-in-mountain behavior, increasing the utilization of mosquito nets and reinforcing the primary health care should be taken as the fundamental measures for malaria control programme.

China↗
PubMed1995

[Clinical application of luteinizing hormone releasing hormone agonist and its impact on bone metabolism].

OBJECTIVES: To evaluate the efficacy of luteinizing hormone releasing hormone agonist (LHRH-A) in the treatment of endometriosis (Em), uterine leiomyoma and adenomyosis, and its impact on bone metabolism. METHODS: Twenty patients, Em 13 (stage II4, III7, IV2), leiomyoma 4 and adenomyosis 3, were selected to receive LHRH-A 200 micrograms intramuscular daily for 3 months. Clinical and ultrasound features serum follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), osteocalcin (BGP) concentrations were compared before and at the end of treatment. Furthermore, 24-hour urinary calcium (Ca), phosphate (P) excretions and bone mineral density (BMD) of radius and lumbar spine measured by single photon absorptiometry (SPA) and dual energy X-ray absorptiometry (DEXA) were also analysed before and at the end of treatment. Patients were followed-up 3-19 months after discontinuation of the drug. RESULTS: At the end of treatment dysmenorrhea disappeared in all 15 cases. Pelvic tenderness and induration improved in 18, endometrioma shrinked in 13 cases. Mean uterine volume of 7 patients with leiomyoma or adenomyosis was reduced by 35% from the basal volume. Serum LH, E2 levels were suppressed significantly (P < 0.05), mean E2 concentration declined from 459.5 +/- 292.0 to 160.3 +/- 110.7 pmol/L (P < 0.001). No significant change was found in serum BGP, urinary Ca, P, and BMD of radius and lumbar spine at the end of therapy, The only side effect was mild not flushes and sweating during treatment. After stopping the drug, 17 patients resumed menses within 2 months. Dysmenorrhea and pelvic mass recurred in 6 months with less severity. One became pregnant in 3 months. CONCLUSIONS: LHRH-A administration is effective in the treatment of Em, leiomyoma and adenomyosis. No significant adverse effect was shown on bone metabolism at the end of 3-month therapy.

Adult↗
PubMed1995

[Inhibition of mRNA expression of silicotic collagen gene by tetrandrine].

Effects of tetrandrine (TT) on types I and III collagen gene mRNA in lung tissues of silicotic rats were studied with RNA dot blot and in situ hybridization by cDNA coding human and mouse Pro alpha 1 (I) and Pro alpha 1 (III) collagen. Results revealed types I and III collagen gene mRNA content in lung tissues of rats exposed to silica dust for two to four months was obviously greater than that in normal lung tissues (P < 0.05), and decreased significantly after treatment with TT (P < 0.05) by dot blot technique. In situ hybridization revealed silver granules of types I and III collagen gene mRNA were scattered in fibroblasts of alveolar septa in normal lung tissues, and in cellular nodes and thickened interstitia of silicotic tissues. It suggested aggregation of collagen in silicotic tissues was caused by enhancement of collagen gene expression, and TT could inhibit directly or indirectly transcription of collagen gene, and thus reduce synthesis of collagen protein in silicotic tissues.

Alkaloids↗
PubMed1995

[Clinical study of improving effect of shuxinyin on abnormal left ventricular diastolic function in coronary heart disease].

There was evidence that abnormal left ventricular diastolic function was common in patients with coronary heart disease which led to symptoms such as dyspnea on exertion, distress in chest etc, even overt congestive heart failure. The changes of left ventricular diastolic function were examined with pulsed doppler echocardiography as well as of clinical symptoms, signs, electrocardiographic findings and plasma lipoprotein after Shuxinyin (SXY) therapy in 31 patients with coronary heart disease and abnormal left ventricular diastolic function. The SXY mainly consists of medicinal herbs capable of tonifying Qi and Yin. After treatment for one month the symptoms, signs and ECG were improved, the symptomatic effective rate was 87.1%. Plasma lipoprotein was reduced (P < 0.05). The main changes in doppler echocardiography were as follows. The peak of E wave, the area of E wave and Dec rate increased significantly (P < 0.01). The ratio of A wave peak to E wave peak was decreased. The changes in peak of A wave, the area of A wave and time index were insignificant (P > 0.05). It was concluded that SXY mainly improved the early left ventricular diastolic functions, increased the peak velocity and volume of rapid left ventricular filling blood flow during the early diastole, and thus alleviated symptoms as well as ECG findings.

Aged↗
PubMed1995

[Full thickness lamellar keratoplasty with viscodelamination of cornea for treatment of bullous keratopathy].

Intrastromal injection of viscoelastic (2% methylcellulose or healon) will facilitate the separation of deep stroma during dissection of recipient stroma. Full thickness lamellar keratoplasty was performed on a smooth graft bed which approached Descemet's membrane. 21 cases with bullous keratopathy were treated and followed up for six months, post-operatively. The symptoms were controlled in all cases and 13 cases were relieved from blindness with corrected visual acuities over 0.05. The safety, efficacy and reoperability of full thickness lamellar keratoplasty with viscodelamination of cornea for treatment of bullous keratopathy make it a promising technique.

Adolescent↗
PubMed1995

Long-term survival without clinical AIDS after CD4+ cell counts fall below 200 x 10(6)/l.

OBJECTIVE: Quantify and study cofactors of long-term survival without AIDS in HIV-1-infected individuals with CD4+ cell counts < 200 x 10(6)/l. DESIGN: Comparison of 579 participants who could be longitudinally evaluated for at least 3 years after the earliest date of first reaching a CD4+ cell count < 200 x 10(6)/l or an AIDS-defining illness (1987 Centers for Disease Control and Prevention definition). SETTING: Ongoing 9-year cohort study with data collected at 6-month intervals. PATIENTS: HIV-1-infected homosexual men. MEASUREMENTS AND MAIN RESULTS: Of the men, 20% did not develop an AIDS illness within 3 years following a confirmed CD4+ cell count < 200 x 10(6)/l; 29 and 28% were diagnosed with a first clinical AIDS illness from 1-3 and < 1 years, respectively, beyond their first CD4+ cell count < 200 x 10(6)/l; 23% were diagnosed with a clinical AIDS illness prior to their first CD4+ cell count < 200 x 10(6)/l. Slower decline of CD4+ cell count (P < 0.001) and presence of higher body-mass index during the period prior to the first CD4+ cell count < 200 x 10(6)/l (P < 0.001) predicted longer time to an AIDS illness once this threshold was reached. Most men had rapid loss of CD4+ cells, total T cells, and hemoglobin during the period after CD4+ cells declined below 200 x 10(6)/l. However, those remaining free of AIDS illnesses the longest arrested their decline in CD4+ cell counts and hemoglobin levels and increased total T cells during this period. Although antiretroviral therapy and Pneumocystis carinii prophylaxis extend AIDS-free survival, 45% of the group who were AIDS-free > or = 3 years after CD4+ cells fell below 200 x 10(6)/l had not used these treatments. CONCLUSIONS: Significant numbers of individuals remain free of illnesses and AIDS symptoms > or = 3 years after CD4+ cell counts drop below 200 x 10(6)/l. This occurs even in the absence of treatment. The associations seen here suggest that host and viral factors play important roles. Thus, further studies are needed to determine the biological basis of long-term survival without AIDS illnesses in HIV-1-immunosuppressed patients.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Successful immunization against Acanthamoeba keratitis in a pig model.

The feasibility of inducing protective immunity to Acanthamoeba keratitis was tested in a pig model. Experiments were designed to determine if ocular infection with Acanthamoeba trophozoites would elicit protection against reinfection. Additional experiments examined whether injection of parasite antigens either intramuscularly, subconjunctivally, or by both routes would induce immunity. Therefore, four groups of animals were examined: (a) pigs that had resolved a primary corneal infection with Acanthamoeba; (b) pigs immunized intramuscularly; (c) pigs immunized subconjunctivally; and (d) pigs immunized intramuscularly and subconjunctivally. Animals were subsequently challenged with parasite-laden soft contact lenses and observed clinically for the appearance of Acanthamoeba keratitis. Acanthamoeba-specific serum antibody titers and blastogenic responses of peripheral blood lymphocytes were determined weekly. The results indicated that intramuscular injection of Acanthamoeba antigens failed to protect against ocular infection even though hosts developed high titers of IgG antibodies and displayed lymphocyte blastogenic responses to parasite antigens. Ocular infection alone failed to stimulate immunity in any of the animals. By contrast, 50% of the hosts immunized subconjunctivally were protected against corneal disease, and 100% of the animals immunized by a combination of intramuscular and subconjunctival administration of parasite antigens were completely protected against two separate ocular challenges with infectious parasites. Protection did not correlate with either IgG antibody titers or blastogenic potentials of peripheral blood lymphocytes. Interestingly, ocular infection alone failed to stimulate immunity to subsequent ocular challenge with infectious parasites. Thus, administration of parasite antigen via the subconjunctival route can protect against Acanthamoeba keratitis.

Acanthamoeba↗