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Biomedical subjects

X L Wang

Publications and source records attributed to X L Wang.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Cloning and identification of an unknown gene encoding 10.6 kDa protein of Schistosoma japonicum].

OBJECTIVE: To screen a new schistosome vaccine candidate. METHODS: Schistosoma japonicum adult cDNA library was screened using sera from immune rabbits vaccinated with irradiated cercariae and monoclonal antibodies against membrane antigen of S. japonicum schistosomula. Three different fragments of S. japonicum cDNA genes were cloned into pGEM-T vector. The sequences of the inserts were determined using an automatic DNA sequencer and were analysed using Blast program. One of the unknown genes (B8) was selected and its ORF sequence (291 bp) was subcloned into eukaryotic expression vector. The recombinant plasmids were identified by restrictive enzymes and PCR amplification. The positive recombinant plasmids (pBK/SjB8) were transformed into host bacteria XL1-blue, and were then induced by IPTG for expression. SDS-PAGE and Western blotting analysis of total cellular protein from the bacteria were performed to detect the gene products. RESULTS: The results demonstrated that ORF of SjB8 gene was subcloned into the plasmid pBK-CMV and could express as fusion protein in XL1-blue. The results of SDS-PAGE and Western-blot also showed that the molecular weight of the fusion protein with 3 kDa beta-galactosidase was approximately 13.6 kDa and the actual molecular weights of the SjB8 was 10.6 kDa. The expressed fusion product of pBK/Sj-B8 could be recognized by immune serum and McAb. CONCLUSION: A new gene of S. japonicum vaccine candidate (SjB8) was cloned into eukaryotic expression vector pBK-CMV and could express 10.6 kDa schistosome protein. The results provide foundation for further study of the protein for its possibility as candidate vaccine.

Animals↗
PubMed2001

[Investigation on genotype constitution of different Plasmodium vivax isolates and its geographical distribution in China].

OBJECTIVE: To investigate the population constitution and geographical distribution of Plasmodium vivax in China using molecular technique. METHODS: Blood-spot filter paper samples with related epidemiological data were collected from vivax malaria patients living in malarious area of 10 provinces (autonomous region) in China. Semi-nested- or nested-allelic-specific PCR genotyping method was used to identify CSP genotypes, families and types of Plasmodium vivax of each isolate from these patients. RESULTS: Of 384 field isolates of Plasmodium vivax, 258 temperate zone family strains were identified, including 14 allelic variant genotypes spreading among 10 sampling provinces; allelic variants sized less than 731 bp were only seen in 5 provinces in southern China; 79 tropical zone family strains including 5 genotypes were also distributed in 5 provinces of southern China south to 25 degrees N. lat; and 14 PV Type-2 strains including 2 genotypes were found in some areas of Hainan and Yunnan Provinces. In addition, 33 isolates from genotype-mixed infections were revealed. CONCLUSION: At present, area north to 25 degrees N. lat. of the country is the sole area prevalent for Plasmodium vivax family strains of temperate zone; there is overlapping distribution of P. v. of temperate zone family and tropical zone family of this parasite in the southern China south to 25 degrees N. lat; where the most complex isolate constitution is in Yunnan and Hainan Provinces, and PV Type-2 strains have been found in some areas of the two provinces. Besides, there were 2 groups of genotype with distinct geographic distribution feature within the temperate zone family.

Animals↗
PubMed2001

[Effect of KB-R7943 on Na(+)-Ca2+ exchange current in guinea pig ventricular myocytes].

AIM: To study whether KB-R7943 has selective inhibitory effect on the inward and outward Na(+)-Ca2+ exchange current (INa-Ca) in guinea pig ventricular myocytes. METHODS: Through setting up the model of intracellular Na(+)-overload during myocardial ischemia and reperfusion, the current-voltage relationship of INa-Ca was recorded using whole-cell patch clamp technique under bi-directional ionic conditions. RESULTS: Currents were elicited by a declining ramp pulse depolarized immediately from holding potential of -40 mV to +60 mV, then repolarized to -100 mV at a speed of 80 mV.s-1 and returned to the holding potential under bi-directional ionic conditions, while the [Na+] was 25 mmol.L-1 in the pipette solution. The currents increased time-dependently and voltage-dependently which reached from (2.51 +/- 0.15) pA.pF-1 to (5.94 +/- 0.13) pA.pF-1 at mV and from (-1.92 +/- 0.13) pA.pF-1 to (-3.17 +/- 0.16) pA.pF-1 at -80 mV (n = 12) after 3 min and there is no significant run-down of the current. KB-R7943 10(-6) mol.L-1 was found to decrease the current to (4.62 +/- 0.05) pA.pF-1 by 29.4% at mV and to (-2.30 +/- 0.18) pA.pF-1 by 22.1% at -80 mV (n = 5) after 5 min. While 10(-5) mol.L-1 KB-R7943 was shown to decrease the current to (3.13 +/- 0.03) pA.pF-1 by 61.7% at mV and to (-1.62 +/- 0.03) pA.pF-1 by 56.9% at -80 mV (n = 7). CONCLUSION: KB-R7943 can block INa-Ca in guinea pig ventricular myocytes. But, it did not show selective inhibition effect on inward and outward currents.

Animals↗
PubMed2001

[The expression levels of GIRK1 and IRK1 in memory deficit rats].

AIM: To study the expression level of GIRK1 and IRK1 in cerebral cortex after aggregated beta-amyloid peptide25-35 injection into the rat cerebral ventricle for different times. METHODS: To test the spatial learning and memory in Morris water maze. To observe GIRK1 and IRK1 expression levels by RT-PCR. RESULTS: In Morris water maze task, the latencies of beta-amyloid peptide treated rats were longer than those of the sham rars in the 4, 5, 8, 10 training periods ("student" t-test, P < 0.05). The expression levels of GIRK1 in beta-amyloid peptide injection day 1 and day 3 groups are decreased significantly compared with sham group (Tukey's test, P < 0.05) and there is no difference between beta-amyloid peptide injection day 17 group and sham group. IRK1 expression levels are no difference among the four groups. CONCLUSION: Injection of aggregated beta-amyloid peptide25-35 into rat cerebral ventricles can induce memory and potassium channel expression changes. Beta-amyloid peptide induced inhibition of GIRK1 expression may have some relations with brain dysfunction.

Amyloid beta-Peptides↗
PubMed2001

[Clinical evaluation of pulpotomy in the treatment of deciduous teeth with deep dentine caries].

OBJECTIVE: To study the curative effect of pulpotomy in the treatment of deciduous teeth with deep caries. METHODS: 45 deciduous molars with deep caries from 3 8 years old children were selected at random. Pulpotomy was performed on these treated teeth. Clinical examination and X-ray films for the treated teeth were taken to follow up all the teeth at 6 months, one year and two years respectively after treatment. RESULTS: At one year after treatment, 45 cases were followed up, the rate of success in clinical examination and in X-ray photographs both were 100%. While at two years after treatment, 42 cases were followed up and 3 cases were lost, the rate of success in clinical examination was 95% and the rate of success in X-ray photographs was 88%. The reasons of the failure were internal absorption and pulpitis followed by fracture and exfoliation of the obturators in the treated teeth. CONCLUSION: Pulpotomy in deciduous teeth with deep caries was a reliable and effective method. It is necessary to follow up the treated teeth by X-ray at regular intervals after treatment.

English Abstract↗
PubMed2000

Human cytomegalovirus immediate early proteins upregulate endothelial p53 function.

Infected endothelial cells are found to be resistant to apoptosis possibly mediated by p53 cytoplasmic sequestration. We explored whether the immediate early 84 kDa protein (IE84) of cytomegalovirus (CMV) is responsible for p53 cytoplasmic sequestration. The endothelial cells were transfected with plasmids containing IE1 and 2 coding regions which are known to synthesize IE84 and 72 proteins. Our study found that p53 expression was significantly elevated in endothelial cells transfected with IE1 and 2 plasmids. However, p53 was only found in the nucleus rather than sequestered in the cytoplasm. We have demonstrated that IE84 and 72 are not responsible for p53 dysfunction caused by CMV infection, rather they upregulate p53 function and promote endothelial apoptosis.

Apoptosis↗
PubMed2000

Interrelations between plasma homocysteine and intracellular S-adenosylhomocysteine.

S-Adenosylhomocysteine, a potent intracellular methylation inhibitor, is suggested as a potential mediator for hyperhomocysteinemia-related vascular changes. We investigated the effect of acute and chronic hyperhomocysteinemia on intracellular S-adenosylhomocysteine and S-adenosylmethionine in rats and humans. Elevated plasma homocysteine in rats infused with homocysteine produced an increase in S-adenosylhomocysteine (P < 0.001) but not S-adenosylmethionine levels (P > 0.05) in various rat tissues. However intraerythrocyte S-adenosylhomocysteine and S-adenosylmethionine levels were not changed in homocysteine-infused rats and human subjects with experimentally acute hyperhomocysteinemia by methionine loading test. In contrast, erythrocyte S-adenosylhomocysteine levels were significantly higher in chronic renal failure patients, who had chronically elevated plasma homocysteine levels, than in either vascular disease patients or healthy controls (P < 0.05). In conclusion, acute hyperhomocysteinemia can increase intracellular S-adenosylhomocysteine levels in tissues actively involved in homocysteine metabolism. The findings are relevant to homocysteine-related endothelial dysfunction since S-adenosylhomocysteine modulates endothelial cell apoptosis.

Adult↗
PubMed2000

Genotype dependent and cigarette specific effects on endothelial nitric oxide synthase gene expression and enzyme activity.

We explored the interactive effects of endothelial nitric oxide synthase (eNOS) genotypes and cigarette smoking on protein levels and enzyme activity in 33 postpartum placentas. Whilst the eNOS protein levels were lower in the rare allele (0.48+/-0.11, n=9 vs. 1. 05+/-0.10, n=24, P<0.01), the eNOS enzyme activity was about 7-fold higher in the rare allele (4556.2+/-255.4 vs. 621.8+/-180.5 cpm/mg/min, P<0.01). Smokers had lower eNOS protein levels (1.07+/-0. 09 vs. 0.50+/-0.19, P<0.05) in both alleles. It reduced the eNOS activities only in the rare allele (non-smokers: 6143.8+/-251.2, n=5, smokers: 2968.5+/-259.4, n=4, 52% reduction, P<0.01). We conclude that associations between eNOS polymorphism and protein levels and enzyme activities are modifiable by smoking, the effects of smoking are dependent on the eNOS genotypes.

Female↗
PubMed2000

Preserved foods in relation to risk of nasopharyngeal carcinoma in Shanghai, China.

A population-based case-control study was conducted in Shanghai, China, to investigate the association between dietary factors and risk of nasopharyngeal carcinoma (NPC). The study included 935 NPC patients aged 15 to 74 years and 1,032 community controls. Exposures to salted fish and other protein-containing preserved food were associated with increased risk of NPC. Individuals who ate salted fish at least once a week had an 80% increase in risk of NPC relative to those who ate salted fish less than once a month (p = 0.07). Compared with those in the lowest quartile of protein-containing preserved foods, subjects in the highest quartile of intake experienced a statistically significant 78% increase in risk of NPC [odds ratio (OR) = 1.78, 95% confidence interval (CI) = 1.37-2.31], with a dose-dependent relationship (p for linear trend < 0.001 ). A similar association between intake of preserved vegetables and NPC risk was observed (OR = 1.39, p for linear trend = 0.003). In contrast, high intake of oranges/tangerines was associated with a statistically significant reduction in risk of NPC (OR = 0.55, p for linear trend < 0.001). When we examined the joint effect of preserved food and oranges/tangerines on risk of NPC, subjects in the highest tertile of preserved food and the lowest tertile of orange/ tangerine intake had a 3-fold increase in risk (95% CI = 2.08-4.91) compared with those in the lowest tertile of preserved food and the highest tertile of orange/tangerine intake.

Adolescent↗
PubMed2000

Non-dietary risk factors for nasopharyngeal carcinoma in Shanghai, China.

A population-based case-control study was conducted in Shanghai, China, to investigate the associations between exposures to various non-dietary variables and risk of nasopharyngeal carcinoma (NPC). A total of 935 NPC patients and 1,032 community controls were included. Active cigarette smoking was a moderate risk factor for NPC [odds ratio (OR) = 1.28, 95% confidence interval (CI) 1.02-1.61]. Results were highly consistent between men and women. It is estimated that 12% of NPC cases in Shanghai, China, can be attributable to cigarette smoking. Among lifelong nonsmokers, there was a strong and statistically significant positive association between NPC risk and exposure to substantial secondhand smoke as a child or as an adult in women. However, the associations among lifelong nonsmoking men were weaker and not statistically significant. The gender differences in risk associated with passive smoking were either statistically significant or almost so. There were excess numbers of NPC patients compared with control subjects who had a history of chronic ear and nose disease (OR = 1.96, 95% CI 1.56-2.46) and a family history of NPC (OR = 7.47, 95% CI 2.14-12.88).

Adolescent↗
PubMed2000

Age-related change of plasma extracellular-superoxide dismutase.

Extracellular-superoxide dismutase (EC-SOD) is a secretory protein that is the major SOD isozyme in extracellular fluids. Plasma EC-SOD mass concentrations in individuals were distributed in two discrete groups with the rare group (2.9%) having a variant of the enzyme with about 15-fold higher plasma levels. The EC-SOD level of the common phenotype in children/youths was significantly higher than that in their parents, and decreased with age, with an average decrease of about 2% per year to age 20. On the other hand, the parents' EC-SOD increased slightly with age. The cord EC-SOD level was the lowest. We observed no significant age-dependent changes in mass concentrations of copper- and zinc-containing SOD (Cu,Zn-SOD) or manganese-containing SOD (Mn-SOD). The total SOD activity in children/youths was significantly higher than that in parents and decreased with age. Three SOD isozymes function together in a complementary manner as a consequence of different cellular and subcellular distributions. However, the results suggest that the changes in EC-SOD levels may be the most sensitive biomarker for age-related changes in the antioxidant capacity.

Adolescent↗
PubMed2000

The alpha-synuclein gene and Parkinson disease in a Chinese population.

OBJECTIVE: To study the Ala53Thr and Ala30Pro mutations of the alpha-synuclein gene in a large number of Chinese patients with Parkinson disease (PD) as well as controls. METHODS: We recruited 183 Chinese patients with sporadic PD, 17 with younger-onset PD (onset age <50 years), and 7 with PD and a positive family history as well as 227 unaffected Chinese control subjects from the outpatient departments of 2 major hospitals in Hong Kong. All subjects were assessed for the the diagnosis of PD by a consultant neurologist or geriatrician. Subjects were interviewed with a standard questionnaire that also questioned for family history. Venous blood samples were obtained from the subjects and genomic DNA was extracted and studied for the presence of Ala53Thr mutation in exon 4 and Ala30Pro mutation in exon 3 of the alpha-synuclein gene using a polymerase chain reaction restriction fragment length polymorphism method. RESULTS: None of the Chinese PD patients or controls had either the Ala53Thr (exon 4) or Ala30Pro (exon 3) mutation of the alpha-synuclein gene. CONCLUSION: We failed to discover Ala53Thr or Ala30Pro mutations in a large number of Chinese patients with PD and control subjects, adding to the emerging consensus that variations in the alpha-synuclein gene are associated with PD in few families worldwide.

Alleles↗
PubMed2000

Endothelial nitric oxide synthase gene sequence variations and vascular disease.

Genes contribute significantly to interpopulation differences in vascular disease. Endothelial nitric oxide synthase (eNOS)-a key regulator of vascular nitric oxide production-has been investigated extensively to determine the relevance of DNA variants in the eNOS gene and vascular diseases. Variants in the promoter region, introns, and exons have been explored in a large number of populations but findings have been inconsistent. This paper reviews the current status of functional significance for reported sequence variations in the eNOS gene and the relevance of these variants to different forms of vascular diseases.

Genotype↗
PubMed2000

Genetic polymorphism of heparan sulfate proteoglycan (perlecan, HSPG2), lipid profiles and coronary artery disease in the Australian population.

Perlecan is one of the three major classes of heparan sulfate proteoglycans (HSPGs) within the cardiovascular system; it interacts with lipid metabolism by binding to lipoprotein lipase (LpL) and apolipoprotein B (apo B) and may be related to vascular disease. We explored interactions between an HSPG2 polymorphism (BamHI marker), and apo B and coronary artery disease (CAD) in patients undergoing coronary angiography. The frequencies of the HSPG2 BamHI +/+, +/-, and -/- genotypes were 4.7, 31.7 and 63.6%, respectively, with a '+' allele frequency of 20.6%. The genotype distribution was in Hardy-Weinberg equilibrium (chi(2)=0.669, P0.05). The +/+homozygotes had the lowest apo B levels (0.74+/-0.06 g/l, n=36) compared to +/- (0.89+/-0.03 g/l, n=241) and -/- (0.93+/-0.02 g/l, n=480) genotypes. Although plasma apo B concentration was the strongest lipid risk factor for significant CAD, the HSPG2 genotypes were not independently associated with the presence of CAD (P=0.640 in males; P=0.224 in females), with significant CAD (P=0.764; P=0.110) or with the number of significantly stenosed coronary arteries (P=0.945; P=0. 335). In Australian Caucasians undergoing coronary angiography the HSPG2 BamHI polymorphism is associated with lower circulating apo B but not with the occurrence or severity of CAD. This may be due to HSPG2-mediated alterations in the HSPG2-apo B-LpL system and requires further exploration.

Australia↗
PubMed2000

Laser pretreatment protects cells of broad bean from UV-B radiation damage.

In order to determine the role of lasers in the stress resistance of broad bean (Vicia faba L.) to ultraviolet-B (UV-B) radiation, the embryos in seeds were exposed to He-Ne laser or CO2 laser radiation. Afterwards they were cultivated in Petri dishes in a constant temperature incubator until the lengths of epicotyls were nearly 3 cm. The epicotyls were then exposed to 1.02, 3.03 or 4.52 kJ m(-2) UV-B radiation, respectively, under 70 micromol m(-2) s(-1) photosynthetically active radiation (PAR) in a growth cabinet. Changes in the concentration of malondialdehyde (MDA), ascorbic acid (AsA) and UV-B absorbing compounds (absorbance at 300 nm) were measured to test the effects of laser pretreatment. The results showed that laser pretreatment of embryos enhanced UV-B stress resistance in the epicotyls of the broad bean by decreasing the MDA concentration and increasing the content of AsA and UV-B absorbing compounds. We suggest that those changes in MDA, AsA and UV-B absorbing compounds were responsible for the increase in stress resistance observed in the broad bean. This is the first investigation reporting the use of laser pretreatment to protect the cells of the broad bean from UV-B-induced damage.

Ascorbic Acid↗
PubMed2000

Lp(a) and conventional risk profiles predict the severity of coronary stenosis in high-risk hospital-based patients.

AIMS: To explore predictive power of Lp(a), of conventional lipoprotein profiles and their carrier proteins, and of biometric measurements, for the presence and severity of angiographically documented coronary disease in high-risk patients, and to compare risk profiles in men and women. METHODS: We determined coronary artery disease (CAD) risk factors in 1308 Australian Caucasian patients (313 women and 995 men) aged < or =65 years who consecutively underwent coronary angiography. RESULTS: In univariate analyses of the risk factors, lipid profiles, Lp(a), cigarette smoking, diabetes, hypertension and obesity were all higher in men and women with CAD and changed significantly with the number of significantly diseased vessels (> or =50% luminal obstruction). When stepwise logistic regression analysis was applied, age (OR 1.06, 95% CI: 1.04-1.09), TC/HDL-C (OR 1.29, 95% CI: 1.15-1.45), male gender (OR 2.64, 95% CI: 1.67-4.16), hyperLp(a) (> or =300 mg/L) (OR 2.09, 95% CI: 1.42-3.07), lifetime smoking dose (OR 1.02, 95% CI: 1.01-1.03), diabetes (OR 2.19, 95% CI: 1.14-4.18) and waist/hip ratio (OR 14.53, 95% CI: 1.21-174.90) were predictive of the disease. Both Lp(a) levels and percentage of hyperLp(a) increased linearly with the number of significantly diseased vessels. When the analyses were conducted in men and women separately, hyperLp(a), TC/HDL-C, lifetime smoking dose and age remained as significant predictors in both groups but the waist/hip ratio was only predictive in women. CONCLUSIONS: As Lp(a) is an independent predictor of the occurrence and extent of coronary stenosis and relevant to treatment options, we suggest that it should be measured routinely in the coronary risk profile assessment of high-risk patients.

Age Factors↗