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Biomedical subjects

X He

Publications and source records attributed to X He.

At least 235 records · Page 13Linked to original sources
PubMed1999

[The 38,000 protein of Mycobacterium tuberculosis is overexpressed in Escherichia coli].

OBJECTIVE: To obtain recombinant 38,000 protein in large quantities and to study its immunologic characteristics by stable expression of the gene encoding for 38,000 antigen of Mycobacterium tuberculosis in E. coli. METHODS: Expression plasmid was constructed with DNA recombinant technique. Positive clones were screened using double digestion and polymerase chain reaction. Recombinant plasmid was transformed into E. coli. Then E. coli carrying recombinant plasmid were induced. The expression of 38,000 antigen was identified by SDS-polyacrylamid gel electrophoresis (PAGE) and immunoblotting. Stained gel was scanned to detect expression level of recombinant antigen. RESULTS: Gel stained with coomassie blue G-250 showed that the induced E. coli carrying recombinant plasmid can produce 38,000 protein at high level. Gel scan showed that 38,000 antigen expression in E. coli was about 36% - 40% of total cellular protein. The recombinant 38,000 antigen existed mostly in inclusion bodies. The recombinant antigen can react with antibodies: serum of pulmonary tuberculosis patients and the goats immuned with Mycobacterium tuberculosis. CONCLUSIONS: Constructed recombinant E. coli can overproduce 38,000 antigen of Mycobacterium tuberculosis. Inclusion bodies are easy to purify and can protect the recombinant antigen from protease, on the other hand, it has not biological activity unless the denatured protein is accurately folded.

Antigens, Bacterial↗
PubMed1999

[A pathological study on the correlation of HPV infection with precancerous cervical lesions].

OBJECTIVE: To study the correlation of cervical condyloma and cancerous lesions with HPV infection. METHODS: Cervical biopsies and histopathological examinations were performed on 179 cases which had abnormal cervical cytological smears. PCR was used to study the HPV-DNA of 128 cases and in situ hybridization (ISH) was used to study 10 cases. RESULTS: 1. Morphologic observations. Most cervical condyloma cases were of the morphologically flat type (97.7%). Two koilocyte types were observed, the classical, or so called diagnostic koilocyte type (39.7%) and the atypical type (60.3%). Cervical condyloma often occurred together with cervical intraepithelial neoplasia (CIN, 42.5%). 2. PCR HPV DNA subtype analysis. Of the 58 cervical flat condyloma, 5 were PHV6/11 positive (8.6%) and 28 were HPV16/18 positive (48.3%). 86.1% of those with atypical koilocyte and 9.1% of those with diagnostic koilocyte had HPV16/18 infection. 66.7% of the lesions in which condyloma coexisted with CIN(2-3) had HPV16/18 infection. CONCLUSIONS: Most cervical condyloma lesions were of the flat type. The appearance of atypical koilocyte is correlated to HPV16/18 infection, which in turn is correlated to the degree of CIN malignancy.

Adult↗
PubMed1999

[Effect of manganese on the brain extrapyramidal development of rat offspring].

The effect of manganese (Mn) exposure on the behavior and extrapyramidal system of offspring were studied. Pregnant rats and their offspring in the experimental group were exposed to manganese from drinking water containing 2 g/L (low Mn-exposed group) or 10 g/L (high Mn-exposed group) of MnCl2 respectively. The latent period for running from the center field to any arm of Elevated Plus Arm Maze of both low and high Mn-exposed group was significantly reduced. But the latent period for reaching the platform above the water in Morris Water Maze of the Mn-exposed group was not different from that of control group. There was a significant increase in the areas, glial fibrillary acid protein(GFAP) immunoreactivity and the average proportional densities of GFAP-positive elements in nucleus caudate and accumbens in the high Mn-exposed group, and a significant reduction in the tyrosine hydroxylase immunoreactivity (TH) and average proportional densities of TH-positive elements in substantia nigra, ventral tegmentum area of midbrain and nucleus caudate in the high Mn-exposed group.

Animals↗
PubMed1999

[Changes of TF and TFPI activities in patients with hypertension or coronary atherosclerotic heart disease].

OBJECT: To investigate the changes of tissue factor (TF) and tissue factor pathway inhibitor(TFPI) activities in patients with hypertension or coronary atherosclerotic heart (CAH) disease. METHODS: TF activity was measured by two-stage assay, and TFPI activity was detected according to Sandset's method. RESULTS: Plasma TF activity in both patients with hypertension and patients with CAH disease was higher than that of normal control(P < 0.05). CONCLUSION: Hypercoagulative state may be involved in the pathogenetic processes of hypertension and CAH diseases. TF and TFPI activities have the likelihood to become the accessory diagnostic indexes for hypertension and CAH diseases.

Adult↗
PubMed1999

[Antihypertensive study of xingnao qingxuan recipe].

OBJECTIVE: To observe the effect of decreasing blood pressure of Xingnao Qingxuan Casuples. METHOD: The blood pressure in normal and anesthetised cats was examined with direct method, the blood pressure in the conscious SHR was obtained by indirect method. RESULTS: Duodenuos administration(id) of XQC of 2.8 g/kg produced a decrease of blood pressure in normal cats; XQC of 1.4, 2.8 and 5.6 g/kg once a day for 14 days produced a dose-dependent reduction of blood pressure in SHR, 3-4 days after administration the blood pressure returned to the level before but the change was not significant. With gastric administration of XQC of 2.8 and 5.6 g/kg for 3 times, the incubation period of eyeball tremor induced by chloroform by dropping into the ear was prolonged by 14.4% and 13.0%, and the keeping time shortened by about 33.3% and 23.3% respectively. Brain basic arterial spasm induced by KCl or 5-HT in dog was relaxed obviously by XQC in vitro experiment. CONCLUSION: XQC has the effect of reducing blood pressure resisting dizziness, which is related to the diastole of brain blood vessel.

Animals↗
PubMed1999

[The expression of suppressor gene p16, p21 and p53 in nasopharyngeal carcinoma].

OBJECTIVE: To evaluate the roles of p16, p21 and p53 protein expression in nasopharyngeal carcinoma (NPC). METHOD: The SP immunohistochemical method was used to detect the expression of p16, p21 and p53 protein in 116 cases of NPC and 15 cases of non-tumour nasopharyngeal tissue. RESULT: 1. The positive expression rates of p16, p21 and p53 protein were 64.7%, 45.7% and 90.5% in NPC respectively. There were significant differences between NPC and non-tumour group (P < 0.05). 2. The expressive rate of p16 protein was 70.6% in non-keratinizing type, 44.8% in undifferentiated type (P < 0.05). 3. The positive expression of p21 was correlated with the expression of p16 and p53. CONCLUSION: Low expressions of p16 and p21 protein may play an important role in carcinogenesis of NPC, and that of p16 has some relation to cell differentiation of NPC. p16 protein may co-operate with p21 protein in development of NPC. p21 protein is probably not produced by stimulating wild-type p53 protein.

Adult↗
PubMed1999

[Phase variation in Salmonella typhimurium phagetype].

The phase variation of phagetype was observed in cultures of Salmonella typhimurium collected from Xinjiang Uygur Autonomous Region during 1980-1993. A few cultures of phagetype 4774 or 4776(full type) may change into another phagetype, i.e. 4000(phase 1) or 0774 and 0776 (phase 2). In reverse, more strains of these phagetype 4000 and 0774(0776) easily back into their original phagetype 4774 or 4776. But some 4000(phase 1) can change to 0776(phase 2), and some 0774(phase 2) can also change to 4000(phase 1). Similarly, a few cultures of phagetype 7776(full type) can change to 7000(phase 1) or 0776(phase 2). More strains of these phagetype 7000(or 7002) and 0776 reverse easily to their original phagetype 7776 or 7774. The variability is 15.6% from full type to phase 1 or phase 2, and is 53.2% from phase 1 or phase 2 to full type. Understanding of phase variation of Salmonella typhimurium phagetype will be helpful to Salmonella phagetyping, and will be significance on epidemiological analysis of Salmonella infection.

Bacteriophage Typing↗
PubMed1999

[Expression of VP7 from a group A rotavirus G4 field strain in baculovirus system].

The full length of G4 type VP7 cDNA was amplified by reverse transcription and polymerase chain reaction (RT-PCR) from a group A rotavirus field strain CR117 circulated in Beijing. The amplified cDNA was first cloned into pTZ18. Sequence analysis showed 96.9% homology of the deduced amino acid between VP7 of CR117 and ST3. Then the VP7 cDNA of CR117 was subcloned into the transfer vector pBacPAK8 downstream of the polyhedrin promotor. Insect cells were cotransfected with recombinant plasmid pBacPAK8-CR117 and Bsu36I-digested BacPAK6 viral DNA. Recombinant baculovirus containing CR117 VP7 gene was obtained by plaque screen and hybridization identification. Specific VP7 with three different molecular weight was detected by Western blot using hyperimmune serum against Rotavirus strain ST3 (G4 type) when expressed in insect cells.

Animals↗
PubMed1999

[Studies on the screening high yield acid protease producing strain L336 by combining microwave irradiation with chemical inducing].

A high yield acid protease producing strain Aspergillus usamii L336 was screened from its parent strain B1 by combining microwave irradiation with inducing of nitrosoguanidine and Li2SO4. By incubation of L336 in shaking flask at 31 degrees C for 88 h, its enzyme activity was 5500 u/mL, and its properties for high yield producing acid protease remained stable after many times of subculture and storage for two months.

Aspartic Acid Endopeptidases↗
PubMed1999

[Distinction of yeast flocculent phenotypes and studies of the physiological and biochemical characteristics of yeast flocculation].

More than 400 yeast strains were examined for their flocculation, and five of them displayed strong flocculation. The 5 strains were divided into two groups which are Flo 1 and NewFlo phenotypes on the basis of their response to sugar inhibition. Related physiological and biochemical characteristics of the two phenotypes' strains were studied. The results showed that the flocculation of Flo 1 phenotype was only inhibited by mannose; it was sensitive to high temperature (70 degrees C), pronase E, trypsin, whereas tolerant to pronase K, chymotrypsin, Ca2+, pH; the flocculation of NewFlo was inhibited by many sugars, such as glucose, maltose, sucrose, mannose; it was sensitive to high temperature (70 degrees C), pronase, Ca2+, pH. The Calcium concentration and pH value of the optimum flocculaton of the Flo1 and NewFlo phenotypes strains were respectively 10 mmol/L-1 mol/L; 3.0-4.5.

Culture Media↗
PubMed1999

[Industrial scale-up of continuous ethanol fermentation using yeast flocs].

Inducing yeast cells to self-flocculate as a cell immobilization method, an industrial scale-up plant composed of 4 air-lift suspended-bed bioreactors in parallel and with a total volume of 400 m3 was established and operated. During a more than 6 months continuous operation, the effluent contained ethanol of 70-80 g/L and residual sugar less than 5 g/L and the ethanol productivity of 7-8 g/L.h-1 was achieved.

Bioreactors↗
PubMed1999

[Corneal limbal stem cell autograft and conjunctiva transplantation for treatment of pterygium].

PURPOSE: To observe the therapeutic effects of corneal limbal stem cell autograft and conjunctiva transplantation for the treatment of pterygium. METHODS: Corneal limbal stem cell autograft and conjunctiva transplantation were performed on 38 cases (43 eyes) with newly developed or recurrent pterygium. The post-operative follow-up period ranged from 3 to 30 months (mean, 10 months). RESULTS: Of 38 cases (43 eyes), there were 34 cases (38 eyes) with stable epithelial healing and recovery of corneal transparency with no abnormal proliferation of pterygium-like tissue. 4 cases (5 eyes) were lost during the follow-up. CONCLUSION: To provide new stem cell source for injured limbus with limbal epithelial autograft transplantation is a reasonable therapeutic method for treatment of pterygium.

Adult↗
PubMed1999

CD28/B7-mediated costimulation is required for parathyroid gland allograft rejection in rats.

The activation of T cells to differentiate and to proliferate is an essential step in the immune response to antigen, especially in cell mediated acute allograft rejection. Besides the interaction of CD3/TCR complex with Ag/MHC complex presented on antigen-presenting cells, a complete T-cell activation and proliferation requires a second costimulatory signal. The interaction of CD28/CTLA-4 and B7 is a major costimulatory pathway for T Cell activation. Inhibition of this pathway results in development of antigen-specific unresponsiveness and clonal anergy. In present study, the biologic function of anti-CD28 monoclonal antibody and its Fab fragment were investigated in vitro and in vivo. The results indicate that mAbCD28 and its Fab fragments could promote the functional recovery of allografts and prolong the graft survival, but could not reverse the acute rejection or induce transplantation tolerance in the rat PTG allograft model. We also found that peripheral TNF-alpha level and NK-cell activity were suppressed in the presence of mAbCD28 and its Fab fragments for a relatively long time after PTG transplantation.

Animals↗
PubMed1999

[The study on the structure of 5,10,15,20-tetra-(4-hexadecylpyridiniumyl)porphyrin LB films].

The film-forming properties of 5,10,15,20-tetra-(4-hexadecylpyridiniumyl)porphyrin bromide (TC16PyP) on the air/water interface were studied. LB films of the amphiphilic porphyrin were prepared on the glass, quartz and SnO2 OTE substrates. The morphology and structure of TC16PyP LB films were characterized by scanning tunnelling microscope, UV-Vis absorption spectra, fluorescence spectra and low-angle X-ray diffraction. The experimental results indicated that the amphiphilic porphyrin TC16PyP has good film-forming properties on the air/water interface, its LB films are stable, in TC16PyP monolayer or LB films the long alkyl chains are not straight and the porphyrin macroring is lying nearly parallel to the substrate surface.

Molecular Structure↗
PubMed1999

[Study on the surface diffuse reflectance ultraviolet-visible spectra of the multicomponent metal catalysts].

In this paper, the surface diffuse reflectance ultraviolet-visible spectra (DRUVS) of two and three components supported metal catalysts for methanation of CO2 by hydrogenation were studied, and the relationship between the activity of catalytic-hydrogenation and the interaction among the components of the catalysts was revealed. Based on the analysis of the DRUVS of the catalysts with defferent amount of promoters in two component catalysts system, the dependence relationship between the characteristic strength of the DRUVS and the catalytic activity was worked out.

English Abstract↗
PubMed1999

[X-ray photoelectron spectroscopy and mass spectrum of organic tin compounds].

The relationship between the chemical displacement of the binding energy and the different chemical environment for 12 organic tin compounds was studied by means of X-ray photoelectron spectronscopy. The different substituents in the compounds have influence on the tin outer electron and Sn-O bond, which was discussed by X-ray photoelectron spectroscopy and mass spectrum.

English Abstract↗