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Biomedical subjects

X Zhao

Publications and source records attributed to X Zhao.

At least 271 records · Page 15Linked to original sources
PubMed2000

[The recognition of the epidemic area of tsutsugamushi disease on Nan Peng Lie Island in China and the strategy of prevention].

OBJECTIVE: To investigate the region for the epidemic area of tsutsugamushi disease. METHODS: Epidemiological studies, Orientia tsutsugamushi isolation, and preventive measures were used. RESULTS: The region belonged to epidemic area of south subtropical zone. The main host was found Rattus norvegicu. The main biological vector was Leptotrombidium deliens. The seasonal trends of the quantity of Rattus norvegicu and Leptotrombidium deliens were consistent with the incidence change of the disease in the region. Orientia tsutsugamushi has been isolated from Rattus norvegicu and Leptotrombidium deliens. Data showed that Orientia tsutsugamushi isolated strains mainly belongs to Karp. Sero-epidemiological data showed that antibodies of Orientia tsutsugamushi are 100.0% positive in the residents of the region and 4.0% in army men. After taking comprehensive preventive measures, the incidence was descending. CONCLUSION: Nan Peng Lie island was proved an epidemic area of tsutsugamushi disease.

Animals↗
PubMed2000

[The susceptible alleles on HLA-DRB 1 of type I diabetes in children in Harbin].

OBJECTIVE: To evaluate association between type I diabetes in children and HLA-DRB1 alleles in Harbin. METHODS: Case-control method was employed, and the PCR-SSP technique was used to identify HLA-DRB1 alleles. RESULTS: The frequencies of DRB1 * 0301 and DR3/4 heterozygosity were significantly higher but the frequency of DR2 was significantly lower in cases than that in controls. In DR4 subtypes, the frequency of DRB1 * 0405 was higher and the frequency of DRB1 * 0406 was lower in cases than that in the controls. The difference between cases and controls in DRB1 * 0901 was not significant. CONCLUSION: DRB1 * 0301 allele and DR3/4 heterozygosity were the important susceptibility and heterozygosity genes while DR2 was the most important protective gene in Harbin. The DR4 possessed double-tendency. DRB1 * 0405 conferred susceptibility and DRB1 * 0406 conferred little protection. The susceptibility conferred by DRB1 * 0901 was not certain in type I diabetes in childhood in China. This study provided useful genetic data on the study of etiology of type I diabetes mellitus.

Alleles↗
PubMed2000

[Effect of green and yellow vegetables on serum carotenoid in children].

OBJECTIVE: To assay the effect of green and yellow vegetables on serum carotenoid concentration and its relation to serum retinol level in children. METHODS: A ten-week green and yellow vegetable intervention study was conducted in children aged 5.3 to 6.4 years of two classes in a kindergarten in Tai'an City of Shandong Province in early September 1996, one class of light-colored vegetable supplemented with daily 193 grams of light colored vegetables, such as cabbage, Chinese cabbage, potato, cucumber, cauliflower and turnip, and 56 grams of yellow-green vegetables, such as spinach, Chinese chive, carrots and red yams; and the other one of yellow-green vegetables with daily 238 grams of yellow-green vegetables and 34 grams of light colored vegetables, both without change in regular diet. Venous blood specimens were collected before and after the experiment from each of the subjects. Serum retinol and carotenoid were determined with high performance liquid chromatography. RESULTS: Serum level of carotenoid, including all-trans-beta-carotene, cis-beta-carotene, cryptoxanthin and lutein were significantly higher after intervention in yellow-green vegetable group, as compared to their baseline levels. However, in the light-colored vegetable group, all those components, including all-trans-beta-carotene, 13-cis-beta-carotene and lutein, decreased significantly after intervention, as compared with those at their baseline levels. Serum carotene level correlated significantly with that of retinol, and their coefficient of correlation was greater in the winter than in the autumn. CONCLUSION: Carotenoid nutrition status can be improved by supplementation of green and yellow vegetables.

Carotenoids↗
PubMed2000

[The development of immune-mediated aplastic anemia in mice can be blocked by cimetidine].

OBJECTIVE: To investigate the effect of H(2) receptor antagonist cimetidine on the development of immune-mediated aplastic anemia (AA) in mice. METHODS: The immune-mediated aplastic anemia mice model was induced by irradiation and half-matched allogeneic lymphocytes transfusion (ALT). The mice were divided into 3 groups: the irradiation alone control group, the irradiation + ALT group (AA group) and the irradiation + ALT + cimetidine group. In cimetidine group, each mouse was intraperitoneally injected cimetidine at different doses once a day for 8 days. On day 14, the bone marrow histology was examined. RESULTS: In 0.5 mg, 1.0 mg and 2.0 mg x (10g)(-1) x d(-1) cimetidine groups, the percentages of hematopoietic tissue volume in bone marrow were (46.58 +/- 20.41)%, (51.88 +/- 24.94)% and (59.12 +/- 32.48)%, respectively, and all much higher than that in AA group [(19.99 +/- 10.98)%, P < 0.01], but were not different from that in irradiated control group [(53.81 +/- 31.72)%, P > 0.05]. CONCLUSION: The development of immune-mediated aplastic anemia in irradiated mice by half-matched allogeneic lymphocytes transfusion was blocked by H(2) receptor antagonist cimetidine.

Anemia, Aplastic↗
PubMed2000

[Assessment on application of Chinese herbs in process of corticosterone reduction in nephrotic syndrome].

OBJECTIVE: To evaluate the effect of Chinese herbs in the process of corticosterone (CS) reduction in nephrotic syndrome. METHODS: One hundred and twenty patients of idiopathic nephrotic syndrome sensitive to prednisone treatment were divided into two groups randomly. The dosage of prednisone used was reduced by routine in both groups but Chinese herbal treatment was added to the treated group in the period of prednisone reduction. The effect of Chinese herbs was estimated by observing the recurrence rate of disease and side-effects of prednisone. RESULTS: The recurrence rate of disease and the occurrence rate of side-effects of prednisone in the treated group were lesser than that in the control group significantly (P < 0.01). CONCLUSION: Additional Chinese herbs in the process of CS reduction in the treatment of CS sensitive nephrotic syndrome could extenuate markedly the recurrence rate of disease and the side-effect of CS reduction.

Adolescent↗
PubMed2000

[Cell cycle analysis and pathological changes of malignant tumors treated with electrochemical therapy].

To investigate the mechanism and to observe the effectiveness of electrochemical therapy(ECT), 33 patients of late stage cancers which treated by ECT were included in this study. Flow cytometry (FCM) and pathology were used to observe the changes of tumor cells before and after ECT. Tumor cells of G1, G2/M, S phases and aneuploid cells were found to be killed almostly and the ratio of apoptosis was elevated greatly after ECT. Also, pathological evidence proved the death of tumor cells and some characters of apoptosis. So, ECT can non-selectively kill tumor cells and induce the apoptosis of them, and FCM was a way to evaluate the effectiveness of ECT.

Adult↗
PubMed2000

[The relationship of cellular DNA content with clinical stage and biological features of colorectal cancer].

The purpose of this study was to explore the relationship of cellular DNA content with clinical stage and biological features of cancer. Flow cytometry was performed on fresh specimens from 86 patients from 1997 to 1998. Forty-five (53.3%) specimens were found to contain cells with abnormal DNA (DNA nondiploidy). Although none of the sex, age, site, differentiation variables correlated with flow cytometric DNA ploidy, nondiploidy was associated with Dukes' stage and lymph node metastasis. Duke's A stage tumors were more frequently diploid than were more advanced tumors, but no difference between Duke's B, C and D stages were observed. These findings suggest that ploidy is associated with some pathological factors.

Aged↗
PubMed2000

[Effects of electromagnetic radiation from cellular telephone handsets on symptoms of neurasthenia].

In order to study the effects of electromagnetic radiation from cellular telephone handsets on symptoms of neurasthenia, 115 and 101 persons with or without handsets were selected. The subjects were investigated by questionnaire on their general health, lifestyle, habit, mental stress, the frequency of using the handsets, living and working environment, the cases of suffered from diseases and symptoms of neurasthenia. The data were analyzed by Chi-square test and Logistic regression statistics. The results showed that the time of using handset was positively associated with depression (P < 0.05), nausea (P < 0.01) and loss of appetite(P < 0.05). The results showed that long time use of cellular telephone handset could induce the symptoms of neurasthenia.

Female↗
PubMed2000

[Impact of glutamine of gut permeability and clinical prognosis on the aging patients undergoing gastric-intestinal operation].

OBJECTIVE: To evaluate the impact of parenteral nutrition supplemented glutamine on aging patients undergoing gastric-intestinal operation. METHODS: 30 patients above 60 years old undergoing gastric-intestinal operation, a randomized double-blind protocol was designed, divided into two groups, received impact isocaloric parenteral nutrition. The study group received alanyl-glutamine [0.5 g/(kg.d)]. To observe plasma amino acids profile, nitrogen balance, intestinal permeability and clinical prognosis, examine clinical chemistry variables and observe the adverse reactions in order to find out its safety. RESULTS: The patients in both groups were comparable prior to the operation. The plasma glutamine level of study group is higher than the control group, it's cumulative nitrogen balance values were prior to the control group, L/M ratio was lower than the control group. The complications related to infection was observed more in the control group. No adverse reaction was observed in both groups. CONCLUSIONS: Ala-Gln-supplemented PN improved nitrogen balance and maintained intestinal permeability, reduced complications.

Aged↗
PubMed2000

[Expression and deletion analysis of EcoR II endonuclease and methylase gene].

OBJECTIVE: To clone complete EcoR II restriction endonuclease gene (ecoR II R) and methyl-transferase (ecoR II M) gene into one vector and to analyzing the expression of the whole system. METHODS: Unidirective deletion subclones constructed with Exo III, ecoR II R/M genes were preliminarily located in the cloned fragments according to the enzyme activities of each subclone, exact deletion sites were determined by sequencing, and transcriptional start sites were mapped by S1 mapping. RESULTS: The DNA fragment which was cloned into pBluescript SK+ contained the complete ecoR II R gene and ecoR II M gene, there are two transcriptional start sites in ecoR II R gene, 132 bp to 458 bp from 3' and of ecoR II R gene are indispensable to enzyme activities and deletion of 202 bp from 3' end of ecoR II M gene made it lose the capability to resist specific cut of EcoR II R enzyme, deletion of coding region and flanking sequence of one gene did not affect the expression of the other gene, the recombinant only containing ecoR II R gene appeared to be lethal to dcm + host. CONCLUSIONS: ecoR II M gene closely linking to ecoR II R gene was very important for the existence of the R-M system in process of evolution, but the key to control EcoR II R enzyme acted later than EcoR II M enzyme did not exist in transcriptional level.

Cloning, Molecular↗
PubMed2000

[Expression of proteolytic enzymes of metastatic tumor cells and the effects of some influencing factors].

OBJECTIVE: To elucidate the types of proteolytic enzymes the dendritic cell sarcoma (DCS) cell expressed in vitro and the effects of modulating factors. METHODS: The proteolytic spots of DCS cells were examined, with ten different proteinase inhibitors, various antibodies and matrix. RESULTS: Aprotinin, EDTA-Na2 and pepstatin could inhibit the proteolysis of DCS cells respectively. Anti-ubiquitin antibody and anti-DCS antibody (1:200-1:100) showed no obvious inhibitory effects. DCS cells spread out fairly well but with no proteolysis. CONCLUSIONS: Under the conditions of our experiments the DCS cells had serine proteinase, metalloproteinase and aspartate proteinase activities. Antiubiquitin antibodies and anti-DCS antibodies showed no obvious influence on the proteolysis of DCS cells. DCS cells displayed different proteolysis status on different matrix.

Aspartic Acid Endopeptidases↗
PubMed2000

[Rotational analysis of fluorescence excitation spectrum of NO2 in the range of 589.3-594.0 nm].

This paper shows the measurement of high-resolution fluorescence excitation spectrum of uncooled NO2 in the range of 589.3-594 nm. The 11 vibronic bands approximately 120 lines in this region were rotationally assigned. The analysis shows that these lines are mainly arise from the parallel transition of 2B2(K' = 0)-->2A2(K" = 0). The spectroscopic parameters describing these bands are obtained. The discussion is given to the complexity of spectrum structure.

Air Pollutants↗
PubMed2000

[Extraction-catalytic kinetic spectrophotometric determination of trace element in tumor tissue].

In this paper an isochromatic dye ion-pairs extraction-catalytic spectrophotometric method for the determination of trace copper is studied. The method is based on the copper catalyzed oxidation of isochromatic dye ion-pairs formed by buthylrhodamine B and bromophenol blue by hydrogen peroxide in ammoniac medium. The reaction time, concentration of isochromatic dye ion-pairs in aqueous phase and degree of reaction are controlled by extraction equilibrium. The detection limit of this method is 0.02 microgram.L-1. The linear range is 0.1-10 micrograms.L-1. The method has been applied to the determination of trace copper in tumor tissue with satisfactory results.

Bromphenol Blue↗
PubMed1999

Direct inhibition of G(1) cdk kinase activity by MyoD promotes myoblast cell cycle withdrawal and terminal differentiation.

MyoD has been proposed to facilitate terminal myoblast differentiation by binding to and inhibiting phosphorylation of the retinoblastoma protein (pRb). Here we show that MyoD can interact with cyclin-dependent kinase 4 (cdk4) through a conserved 15 amino acid (aa) domain in the C-terminus of MyoD. MyoD, its C-terminus lacking the basic helix-loop-helix (bHLH) domain, or the 15 aa cdk4-binding domain all inhibit the cdk4-dependent phosphorylation of pRb in vitro. Cellular expression of full-length MyoD or fusion proteins containing either the C-terminus or just the 15 aa cdk4-binding domain of MyoD inhibit cell growth and pRb phosphorylation in vivo. The minimal cdk4-binding domain of MyoD fused to GFP can also induce differentiation of C2C12 muscle cells in growth medium. The defective myogenic phenotype in MyoD-negative BC3H1 cells can be rescued completely only when MyoD contains the cdk4-binding domain. We propose that a regulatory checkpoint in the terminal cell cycle arrest of the myoblast during differentiation involves the modulation of the cyclin D cdk-dependent phosphorylation of pRb through the opposing effects of cyclin D1 and MyoD.

Amino Acid Sequence↗
PubMed1999

A role for the clathrin assembly domain of AP180 in synaptic vesicle endocytosis.

We have used the squid giant synapse to determine whether clathrin assembly by AP180 is important for synaptic vesicle endocytosis. The squid homolog of AP180 encodes a 751 amino acid protein with 40% sequence identity to mouse AP180. Alignment of squid AP180 with other AP180 homologs shows that amino acid identity was highest in the N-terminal inositide-binding domain of the protein and weakest in the C-terminal clathrin assembly domain. Recombinant squid AP180 was able to assemble clathrin in vitro, suggesting a conserved three-dimensional structure that mediates clathrin assembly despite the divergent primary sequence of the C-terminal domain. Microinjection of the C-terminal domains of either mouse or squid AP180 into the giant presynaptic terminal of squid enhanced synaptic transmission. Conversely, a peptide from the C-terminal domain of squid AP180 that inhibited clathrin assembly in vitro completely blocked synaptic transmission when it was injected into the giant presynaptic terminal. This inhibitory effect occurred over a time scale of minutes when the synapse was stimulated at low (0.03 Hz), physiological rates. Electron microscopic analysis revealed several structural changes consistent with the inhibition of synaptic vesicle endocytosis; peptide-injected terminals had far fewer synaptic vesicles, were depleted of coated vesicles, and had a larger plasma membrane perimeter than terminals injected with control solutions. In addition, the remaining synaptic vesicles were significantly larger in diameter. We conclude that the clathrin assembly domain of AP180 is important for synaptic vesicle recycling at physiological rates of activity and that assembly of clathrin by AP180 is necessary for maintaining a pool of releasable synaptic vesicles.

Adaptor Proteins, Vesicular Transport↗
PubMed1999

Effects of quercetin on the release of endothelin, prostacyclin and tissue plasminogen activator from human endothelial cells in culture.

Quercetin and related flavonoids are naturally occurring polyphenolic compounds with multiple pharmacological activities. Using cultured human umbilical vein endothelial cells, we investigated the effects of quercetin on endothelin (ET-1) and tissue plasminogen activator (t-PA) release induced by thrombin. We observed that when endothelial cells pretreated with 5 or 50 microM of quercetin were incubated for 4 and 24 h with thrombin, ET-1 concentration-dependently decreased (n = 6, P < 0.01, at 4 h IC50 = 1.54 microM, at 24 h IC50 = 2.78 microM). Under the same experimental conditions, quercetin significantly increased t-PA (n = 6, P < 0.01, at 4 h EC50 = 0.71 microM and at 24 hrs EC50 = 0.74 microM). In the same preparation, we evaluated prostacyclin (PGI2) release, induced by thrombin activated platelets, as determined by a 6-Keto-PGF1alpha radioimmunoassay. Following the treatment of cultured endothelial cells with activated platelets, the concentration of 6-Keto-PGF1alpha was significantly increased (P < 0.01). Quercetin (1, 5, and 20 microM) inhibited PGI2, in a concentration-dependent manner (n = 6, P < 0.05). Our data indicate that quercetin modulates the release of ET-1, t-PA, and PGI2 from vascular endothelial cells.

6-Ketoprostaglandin F1 alpha↗
PubMed1999

Risk factors for meningioma in adults: a case-control study in northeast China.

A hospital case-control study of meningioma was conducted in Heilongjiang Province in northeast China between September 1989 and December 1996. It included 183 cases of newly diagnosed primary meningioma and 366 individually matched hospital controls with non-neoplastic and non-neurological disease selected from six major hospitals. Cases and controls were matched by sex, age and area of residence and interviewed in the hospital wards to obtain information on medical history, occupation and lifestyle. No association with liquor or beer consumption was apparent. Cigarette smoking was positively associated with meningioma risk in women but not in men. In women, compared with non-smokers, the adjusted OR for pack-years of smoking above the median (124) was 6.2 (CI 2.04-18.87). Both of these observations contrast with the results of a study of glioma in the same population, using similar methods. The risk of meningioma was positively associated with reported occupational exposure to lead, tin, cadmium and ionising radiation in both genders.

Adult↗