Biomedical subjects

Y Yang

Publications and source records attributed to Y Yang.

At least 271 records · Page 15Linked to original sources

PubMed2001

[Correlation between electroretinographic findings, clinical phenotypic and genotypic analysis in Duchenne and Becker muscular dystrophy].

OBJECTIVE: To explore the relationship between electrophysiological changes, clinical phenotype and genotype in Duchenne and Becker muscular dystrophy(DMD/BMD), to address the expression and roles of dystrophin and its isoforms on the retina, and to inquire into the molecular mechanism of the abnormal electroretinogram(ERG) on DMD/BMD patients with different genotype. METHODS: Gene deletions were screened by multiplex DNA amplification with eleven primers on twenty-two consecutive patients with DMD and BMD, and then, the ERG was tested according to international ERG standard. RESULTS: ERG phenotype was associated with the site of DMD gene defects rather than the severity of the phenotype. Patients with deletion in the central region of the gene had more severe changes in the scotopic ERG as compared to those with gene non-deletion. CONCLUSION: The ERG genotype-phenotype correlation suggests that DP260 may play the most important role in the retinal neurotransmission.

Adolescent↗

PubMed2001

[Genetic polymorphism of eight STR loci in the Han population in Henan province].

OBJECTIVE: To investigate the allele frequencies of eight short tandem repeats(STR) loci: TH01, FES, D19S400, D7S820, D16S539, D20S161, D3S1545 and D5S818 in Han population in Henan province. METHODS: DNA was extracted with phenol-chloroform from EDTA-blood samples of the unrelated individuals in Henan province and amplified with PCR technique. The PCR product was analyzed with the undenatured PAGE vertical electrophoresis and silver-stain. RESULTS: The authors got the frequencies of the eight loci. The heterozygosities of the eight loci are 0.66, 0.67, 0.80, 0.76, 0.79, 0.79, 0.78 and 0.78; the discrimination powers are 0.83, 0.83, 0.94, 0.91, 0.93, 0.93, 0.92 and 0.92. CONCLUSION: The heterozygosities of the eight loci are high and the frequencies are in good agreement with Hardy-Weinberg equilibrium, so the eight loci can be used in individual identification testing.

Alleles↗

PubMed2001

[Analysis of the non-deletion alpha-thalassemia mutations by PCR temperature gradient gel electrophoresis].

OBJECTIVE: To develop a PCR-temperature gradient gel electrophoresis(TGGE) method applied to screening for the point mutations causing the non-deletion alpha-thalassemia. METHODS: The entire alpha2-globin gene fragment (1085 bp) was selectively amplified from human genomic DNA with different genotypes of alpha-thalassemia and a 543 bp fragment spanning the exon 2 and exon 3 of the alpha2-globin gene was amplified with a pair of nested primers. The condition of perpendicular and parallel TGGE for the two different fragments in length was optimized and the candidate mutant was confirmed by DNA sequencing. In pilot study, 15 samples with suspected non-deletion alpha-thalassemia were screened for point mutations in alpha-globin gene. RESULTS: Hb Constant Spring (Hb CS) and Hb Quong Sze (Hb QS), two most commonly types of the non-deletion alpha-thalassemia distributed in Chinese, and a rare type of the Hb Westmead mutation, alpha2 CD122 CAC-->CAG(His-->Gln) could be detected by PCR-TGGE. Among those 15 samples screened for alpha-thalassemia mutation were 10 samples with Hb CS mutation, 2 samples with Hb QS mutation, 2 samples with Hb Westmead mutation, and a previously unreported one, alpha2 CD31 AGG-->AAG(Arg-->Lys), confirmed by DNA sequencing. CONCLUSION: The present PCR-TGGE method could be a useful tool for the molecular screening for the point mutations causing alpha-thalassemia and alpha-globin gene polymorphism.

Electrophoresis↗

PubMed2001

Effects of nitric oxide synthase inhibition on angiotensin receptors and metabolism in the pregnant hypertensive rat.

Endothelial dysfunction and a consequent decrease in nitric oxide production have been implicated in the pathogenesis of pre-eclampsia. A prominent feature of the pre-eclamptic syndrome is a loss of the pregnancy-induced refractoriness to infused pressor agents, such as angiotensin. In this study, we sought to determine whether a decrease in nitric oxide production might be linked via changes in angiotensin II receptors and angiotensin II metabolism to changes in pressor sensitivity to infused angiotensin II. Pregnant and non-pregnant spontaneously hypertensive rats (SHRs) were randomly allocated to receive 5 mg x kg(-1) x day(-1) N(G)-nitro-L-arginine methyl ester (L-NAME) in the drinking water or drinking water alone from days 7 to 14 of gestation. Steady-state metabolic clearance studies of angiotensin II were then performed, or tissues were harvested for angiotensin II receptor studies. Treatment with L-NAME caused an increase in systolic pressure (P<0.001) in both pregnant and non-pregnant rats, while urinary protein excretion increased only in the pregnant SHRs (P<0.001). Plasma angiotensin II levels were significantly increased in the L-NAME-treated SHRs compared with controls (non-pregnant, P<0.0005; pregnant, P<0.01). The metabolic clearance rate of angiotensin II was decreased by L-NAME treatment in non-pregnant SHRs (P<0.05), but was increased by L-NAME treatment in the pregnant rats (P<0.01). In the aorta, the angiotensin II receptor number increased after treatment with L-NAME in both non-pregnant (P<0.0005) and pregnant (P<0.05) SHRs, and the dissociation constant increased in the non-pregnant SHRs (P<0.005). Thus treatment of SHRs with L-NAME increased blood pressure, as well as the circulating angiotensin II concentration and vascular angiotensin II receptor expression. However, treatment with L-NAME did not affect pressor sensitivity to infused angiotensin II. We conclude, therefore, that although a decrease in nitric oxide production is associated with changes in angiotensin II concentrations and receptor numbers, it does not induce changes in pressor sensitivity to infused angiotensin II in the SHR.

Analysis of Variance↗

PubMed2001

"Hybrid" revascularization: video-thoracoscopy assisted MIDCAB combined with angioplasty.

A "hybrid" revascularization technique has been developed for cases in which a chronic total occlusion of the left anterior descending coronary artery (LAD) cannot be recanalized by percutaneous coronary intervention, but the lesions in the right coronary artery and/or left circumflex artery are very good candidates for angioplasty. This technique, which uses video-thoracoscopy assisted minimally invasive direct coronary artery bypass to recanalize the occluded LAD and angioplasty to dilate favorable lesions in other vessels, would achieve complete revascularization in selected patients with multi-vessel disease. In this preliminary study of four patients, angioplasty and stenting were successful in all patients without any complications; complete revascularization was achieved in all 4 patients. No recurrence of angina and no cardiovascular events developed during follow-up; this study therefore supports the belief that the "hybrid" revascularization technique is both feasible and safe.

Adult↗

PubMed2001

Human papillomavirus and p53 protein immunoreactivity in condylomata acuminatum and squamous cell carcinoma of penis.

AIM: To determine the immunoreactive pattern of human papillomavirus (HPV) antigen and p53 protein in condylomata acuminatum (CA) and squamous cell carcinoma (SCC) of penis. METHODS: Immunohistochemistry for HPV and p53 were performed in 40 specimens of formalin fixed, paraffin embedded tissues using a polyclonal (rabbit) antibody against HPV and a monoclonal (mouse) antibody against human p53 protein. Twenty one cases of CA and nineteen cases of SCC were examined. RESULTS: HPV antigen was detected in all 21 CA and 2 penile SCC. p53 protein overexpression was observed in 12 of 19 (63%) SCC in which 6 cases were strong positive. Five of 21 CA (24%) showed low-grade p53 protein overexpression. CONCLUSION: CA is related to HPV infection and some cases show p53 protein low-grade overexpression. In contrast, p53 protein overexpression is common in penile SCC, which is seldom related to HPV infection.

Carcinoma, Squamous Cell↗

PubMed2001

[Measurement of formaldehyde in disinfectant with spectrophotometry].

Formaldehyde in disinfectant was measured by acetylacetone spectrophotometry. The regression equation was linear when the formaldehyde concentration was smaller than 10 micrograms/ml. The detection limit was 0.08 microgram/ml. The accuracy was less than 3.9% and the recovery varied between 100.2%-108.2% for formaldehyde disinfectant with different concentration, which was similar to titrimetry. It was demonstrated that the method was simple, reproducible, sensitive, precise and accurate, making it important for assay of formaldehyde in disinfectant when disturbance caused titrimetry unavailable.

Disinfectants↗

PubMed2001

[Effect of zinc on the activities of ATPase of erythrocyte membrane].

The effects of zinc on the activities of Na+, K(+)-ATPase and Ca2+, Mg(2+)-ATPase of erythrocyte membrane were studied both in vivo and in vitro. Male adult rats were divided into three groups and fed on diets with different concentration of zinc (2.2, 28 and 128 mg/kg diet). Eight rats of each group were sacrificed after 25 days and the activities of the two ATPase were measured. The rest rats were changed diet for an other seven days to detect the sensitivities of the ATPases. The activities of these ATPase were also determined in fresh human erythrocyte membrane treated with different concentration of zinc (0, 5, 10, 50, 100, 500 mumol/L). The results showed that the activities of both Na+, K(+)-ATPase and Ca2+, Mg(2+)-ATPase were in close relationship with zinc concentration, too low or too high zinc could decrease them. Compared with Na+, K(+)-ATPase, Ca2+, Mg(2+)-ATPase was more sensitive to zinc deficiency and in a slower reaction to zinc supplement, but it could stand higher zinc concentration. It was concluded that zinc played an important role on maintaining the normal activities of Na+, K(+)-ATPase and Ca2+, Mg(2+)-ATPase.

Animals↗

PubMed2001

Evolution of cross-linked non-viral gene delivery systems.

Developing a non-viral gene delivery system that functions in vivo raises the challenge of finding solutions to efficiently deliver DNA to the cell surface that are also compatible with the efficient release of DNA into the cytosol. The stability, particle size and charge of DNA polyplexes and lipoplexes may be optimized to mediate efficient in vitro transfection only to find that different properties are necessary for successful in vivo transfection. Despite their versatility and improved safety, non-viral gene vectors still lack appreciable in vivo transfection efficiency compared to viral vectors. An emerging theme in recent studies is the use of cross-linking to achieve balance between the stability of polyplexes and lipoplexes in the blood and the controlled release of DNA in the cytosol. This review evaluates the evolution of cross-linking strategies aimed at transiently stabilizing non-viral gene delivery systems.

Cross-Linking Reagents↗

PubMed2001

[Influence of environmental factors on CH4 emission from Reed Wetland].

Determination of CH4 emission from reed wetland in Liaohe delta, China using closed chamber(enclosure area 0.64 m2) technique showed that average emission rate of CH4 was 520 micrograms.m-2.h-1 with significant seasonal patterns. When soil redox potential reached -110 mV, CH4 occured and increased with its decrease. CH4 emission was also influenced by water management and reduced with deep water cover. During the period of measurement, there was positive relation between temperature and CH4 flux(R2 = 0.196, n = 21, P < 0.05). In addition, the experimental result also showed that the methanogenic activites in 0-5 cm soil layer were higher and decreased obviously with soil deepening.

Methane↗

PubMed2001

[Studies of localization of black streak body gene in Drosophila melanogaster].

Mutation type of body color shows frequently yellow (y), black (b) and ebony (e) in Drosophila melanogaster and locates on X, second and third chromosom respectively. A mutant of black streak (bsr) is a spontaneous mutation strain building in the laboratory in 1991. Whether this mutation strain is rediscovered on the primary style or not. We have discussed this problem with general cross breeding and complementation test. The result of complementation test indicated that it is a mutant in first filial generation with trans heterozygote and that it is few wild in second filial generation with cis teterozygote due to crossing over in crossing bsr and e. But, we believe that bsr and e is located same loci (93D2) but not the same sites. This report discussed for correlation inter-gene body color and ruleless of heredity passing down for black streak body.

Animals↗

PubMed2001

[Two virus strains of isolated in China are recombinant alphaviruses].

OBJECTIVE: To determine the classification, phylogenetic and genetic type of XJ-90260 and XJ-91006 viruses isolated in China. METHODS: Two pairs of specific primers were designed to amplify the NSP4 and E1-3' UTR genes of XJ-90260 and XJ-91006 viruses and the nucleotide sequences between them and with that of other Alphavirus were compared. RESULTS: The nucleotide sequences identity between XJ-90260 and XJ-91006 viruses was 100% and has showed the highest with WEE, comparing with the other 26 Alphaviruses in 3'-UTR. NSP4 gene of XJ-90260 and XJ-91006 viruses high homologous with EEE virus and E-1 gene high homologous wih SIN virus. XJ-90260 and XJ-91006 viruses belong to the B group of WEE and are closest to the Russian strain (Y62-33) by phylogenetic analysis. CONCLUSION: XJ-90260 and XJ-91006 viruses isolated in China are recombinant Alphaviruses, they belong to the same genetic type as WEE does.

Alphavirus↗

PubMed2001

Efficacy trial of Vi polysaccharide vaccine against typhoid fever in south-western China.

OBJECTIVE: To test the efficacy of locally produced Vi vaccine over a time period of longer than one year. METHODS: A double-blinded, randomized field trial was performed in Guangxi Zhuang Autonomous Region in south-western China, using 30 micrograms doses of locally produced Vi. Enrolled subjects were 3-50 years of age, although the majority (92%) were school-aged children, who have the highest rate of typhoid fever in this setting. A total of 131,271 people were systematically allocated a single dose of 30 micrograms of Vi polysaccharide or saline placebo. The study population was followed for 19 months, with passive surveillance conducted in the Ministry of Health and the Regional Health and Anti-epidemic Centre (HAEC). Clinically suspected cases of typhoid fever were confirmed by blood culture, or by serological reaction with O-antigen (Widal tests). FINDINGS: After 19 months, there were 23 culture-confirmed cases of typhoid fever in the placebo group versus 7 cases in the Vi group (Protective efficacy (PE) = 69%; 95% CI = 28%, 87%). Most of the isolates were from school-aged children: 22 cases in the placebo group versus 6 in the Vi group (PE = 72%; 95% CI = 32%, 82%). No serious post-injection reactions were observed. The locally produced Vi polysaccharide vaccine showed levels of protective efficacy similar to those for Vi vaccine produced in industrial countries. CONCLUSION: The slightly higher dose of vaccine did not seem to alter efficacy significantly in China.

Adolescent↗

PubMed2001

[Total water pollution load determining on Tianxi catchment area in Shenyang city].

This paper analysed and determined the total water pollution load of Tianxi catchment area in Shenyang city systematically; by giving the reliability measurement to the total pollution load, put forward the suggestions to improve the system information reliability. It was found that to strengthen monitoring and investigation for the pumping station is of great advantage to control the pollutants of heavy metals, moreover, by adding monitoring to the Huanglatuozi section of Xi river, not only can the pollution load be identified clearly but also organic pollutants can be controlled more accurately and timely.

China↗

PubMed2001

[Accumulation of heavy metals in urban soils and impacts on microorganisms].

Compared with rural soils, urban soils in Aberdeen city possessed obviously different microbial features: higher in microbial basal respiration strength, and microbial ecophysiological parameters Cmic/Corg and qCO2, but lower in microbial biomass, also much more rapid in consuming carbon sources deduced from Biolog data. Urban soils showed different characteristics in heavy metals as well. Apparent accumulation of Pb, Zn, Cu, Ni were observed, in which Pb mainly related with iron oxides, Ni, Zn existed in residual forms, Cu exhibited same importance of different chemical forms but for soluble forms. Principal component analysis results reflected the overwhelming factor to control the difference of microbial features between urban and rural soils was soluble Pb, then soluble Zn, soluble and organic bonded Cu and Ni also contributed in some degree.

Bacteria↗

PubMed2001

[High expression of rabbit sperm membrane protein rSP10 in Escherichia coli and preparation of its specific antisera].

To study the position and immunogenicity of rSP10, the rabbit rsp10 gene which did not include sequences coding for signal peptides was inserted into expression vector pET30a. An in-frame fusion protein was made such that a His6 stretch was produced at the N terminus of re-rSP10. High expression was obtained, the amount of re-rSP10 up to 67% in the total bacterial protein. The re-rSP10 was purified by DEAE chromatography and the yield of purified re-rSP10 was approximately 50 micrograms/mL of culture. Western blotting analysis of re-rSP10 with rabbit polyclonal sera raised against rabbit sperm membrane protein showed that the synthesized antigen possessed immunogenicity of rSP10. Specific antisera against re-rSP10 was induced using purified re-rSP10 as an antigen. The motility of capacitated sperms were affected but no aggregation was observed.

Animals↗

PubMed2001

[Study on the improvement of process technology of L(+)-tartaric acid fermentation].

This work proposes an improved process technology of L(+)-tartaric acid produced by using cis-epoxysuccinates as the substrate for fermentation. The key to the question is to apply dipotassium cis-epoxysuccinate as the substrate instead of disodium cis-epoxysuccinate. As compared with the original process technology, the improved one has prominent advantages: 1. High yield of acid, increased by 20%-30% over the old one; 2. High rate of recovery, from about 60% to 80%; 3. One of the raw materials is cheaper, the KOH is expensive than NaOH, but half of the K kions could be used cyclically, and the varied products could be obtained easily; 4. The tough working procedure of filtration of fermented liquor could be evaded, the total working procedures might increase to some extent, but the cost of production will be reduced obviously, it is advantageous to industrial production.

Fermentation↗

PubMed2001

Nuclear receptor-mediated repression of human cholesterol 7alpha-hydroxylase gene transcription by bile acids.

Hydrophobic bile acids strongly repressed transcription of the human cholesterol 7alpha-hydroxylase gene (CYP7A1) in the bile acid biosynthetic pathway in the liver. Farnesoid X receptor (FXR) repressed CYP7A1/Luc reporter activity in a transfection assay in human liver-derived HepG2 cells, but not in human embryonic kidney (HEK) 293 cells. FXR-binding activity was required for bile acid repression of CYP7A1 transcription despite the fact that FXR did not bind to the CYP7A1 promoter. FXR-induced liver-specific factors must be required for mediating bile acid repression. Bile acids and FXR repressed endogenous CYP7A1 but stimulated alpha-fetoprotein transcription factor (FTF) and small heterodimer partner (SHP) mRNA expression in HepG2 cells. Feeding of rats with chenodeoxycholic acid repressed CYP7A1, induced FTF, but had no effect on SHP mRNA expression in the liver. FTF strongly repressed CYP7A1 transcription in a dose-dependent manner, and SHP further inhibited CYP7A1 in HepG2 cells, but not in HEK 293 cells. FXR only moderately stimulated SHP transcription, whereas FTF strongly inhibited SHP transcription in HepG2 cells. Results revealed that FTF was a dominant negative factor that was induced by bile acid-activated FXR to inhibit both CYP7A1 and SHP transcription. Differential regulation of FTF and SHP expression by bile acids may explain the wide variation in CYP7A1 expression and the rate of bile acid synthesis and regulation in different species.

Animals↗