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B Chen

Publications and source records attributed to B Chen.

At least 181 records · Page 10Linked to original sources
PubMed2000

Genetic polymorphism of 4 STR loci on chromosome 17 in Chinese Han.

OBJECTIVE: To analyze genetic polymorphism of D17S1290, D17S1293, D17S1303 and D17S1308 in Chinese Hans. METHODS: Fifty unrelated individuals were analyzed by PCR amplification fragment length polymorphism analysis method. RESULTS: 9, 7, 5, 5 alleles were observed at these 4 STR loci respectively, the genotypes distributions in Chinese Hans were in accordance with Hardy-Weinberg equilibrium, the expected heterozygosities for these loci were 0.770, 0.828, 0.608, 0.669 respectively, the polymorphism information contents(PIC) were 0.763, 0.820, 0.602, 0.662 respectively. CONCLUSION: The results demonstrate these 4 STR loci can be used for genetic analysis.

China↗
PubMed2000

Effect of dietary fatty acids on tumorigenesis of colon cancer induced by methyl nitrosourea in rats.

We studied the effect of dietary fatty acid composition on the tumorigenesis of colon cancer induced by methyl nitrosourea (MNU) in rats. Five groups of Sprague-Dawley male rats were fed with semi-synthetic diets that contained different proportions of beef tallow, soybean oil, alkana oil, corn oil, and fish oil for 180 days. Each group was matched with a control group fed with the same diet. The experimental groups were given MNU in PBS i.p. 6 times at weekly intervals. The control groups were given PBS only. The incidence of colon cancer, the average volume of the tumors, PCNA, cell kinetics, membrane lipid fluidity, ALP activity, and the content of PGE2 in colonic mucous and the fatty acid distribution in the testis pad fat were measured at the end of the experiment. The results showed that the incidence of colon cancer and the average volume of the tumors in animals fed with diets that contained mainly beef tallow, soybean oil, or alkana oil were significantly higher than that in animals fed with diets that contained mainly fish oil. The diet containing 13.9% of SFA, 16.4% of MUFA, and 68.8% of PUFA showed the strongest inhibition effect. This may be due to the mechanism of protecting the membrane lipid fluidity, decreasing the amount of PCNA in colon cells, the number of propidium iodine-labeled cells in S phase, the activity of ALP and inhibiting the production of AA and thus decreasing the amount of PGE2.

Alkaline Phosphatase↗
PubMed2000

[Cytochrome P450 1A1 and cytochrome P450 2E1 gene polymorphisms in Guangzhou Hans].

OBJECTIVE: To determine the distribution of cytochrome P450 1A1(CYP1A1) and cytochrome P450 2E1(CYP2E1) gene polymorphisms in Guangzhou Hans. METHODS: A total of 150 healthy Guangzhou Hans were studied with PCR-RFLP and ASA techniques. Current results were compared with the data on other ethnic groups. RESULTS: In the 150 individuals tested, the frequencies of the m1(Msp I-) and m2(Msp I+) alleles of the Msp I polymorphic site in the 3' non-coding region of the CYP1A1 gene were found to be 62.33% and 37.67%, respectively. The observed frequencies of the m1m1, m1m2 and m2m2 genotypes were found to be 40%, 44.67% and 15.33%, respectively, which met Hardy-Weinberg equilibrium. The frequencies of the A and G alleles of the exon 7 A4889G polymorphic site in the CYP1A1 gene were found to be 79% and 21%, respectively. The observed frequencies of the AA, AG and GG genotypes were found to be 62.67%, 32.67% and 4.66%, respectively, which met Hardy-Weinberg equilibrium. A close linkage between the Msp I polymorphism and exon 7 A4889G polymorphism was observed in Guangzhou Hans(chi(2)=62.2358, P<0.005). The frequencies of the C1(Rsa I+, Pst I-) and C2(Rsa I-, Pst I+) alleles of the Rsa I polymorphic site in the 5' flanking region of the CYP2E1 gene were found to be 85.3% and 14.7%, respectively. The observed frequencies of the C1C1, C1C2 and C2C2 genotypes were found to be 67.3%, 29.3%, and 3.4%, respectively, which met Hardy-Weinberg equilibrium. CONCLUSION: The frequencies of the CYP1A1 and CYP2E1 gene polymorphisms in Guangzhou Hans were similar to those in Japanese population, but were significantly different from those in European populations.

China↗
PubMed2000

Preliminary studies on parkin gene deletion at exons 1 to 6 in Chinese patients with praecox Parkinson's disease.

OBJECTIVE: To search parkin gene deletion mutations at exons 1 to 6 in Chinese patients with praecox Parkinson's disease (PPD) and analyze them together with the clinical features of PPD. METHODS: DNA was extracted from peripheral blood of PPD patients; deletion mutations of parkin gene were identified by PCR amplification and agarose gel electrophoresis. The clinical data were analyzed together with the above information. RESULTS: Out of 21 patients, 2 had exon 1 deletion, 2 exon 4 deletion, and 1 exon 6 deletion. The mean age of the patients with deletion mutation was 45.7+/-1.8 years. All of the patients who had parkin gene deletion mutation had tremor, rigidity and bradykinesia, but athetosis and family history of PD were not found. In additon, the deletion mutations of parkin gene at exons 2, 3, 5, were not found. CONCLUSION: There are deletion mutations of parkin gene at exons 1,4,6 in PPD of Chinese, and such deletions generally happen on middle-aged patients.

Adolescent↗
PubMed2000

Dopamine receptor gene polymorphisms in Guangzhou Hans.

OBJECTIVE: To determine the distribution of dopamine D2, D3, and D5 receptor(DRD2, DRD3, DRD5) gene polymorphisms in Guangzhou Hans. METHODS: A total of 141 healthy Guangzhou Hans were studied by the use of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR-amplification of specific allele (PASA) techniques. Current results were compared with the data on other ethnic groups. RESULTS: Within the 141 individuals tested, the frequencies of the A1(Taq I-) and A2(Taq I+) alleles of the TaqI A mutation site in the 3'non-coding region of the DRD2 gene were found to be 48% and 52%, respectively. The observed frequencies of the A1A1, A1A2 and A2A2 genotypes were found to be 17%, 52% and 31%, respectively, which met Hardy-Weinberg equilibrium. The frequencies of the A1 and A2 alleles of the Bal I mutation site in the exon 1 of DRD3 gene were found to be 73% and 27%, respectively. The observed frequencies of the A1A1, A1A2 and A2A2 genotypes were found to be 53%, 39% and 8%, respectively, which met Hardy-Weinberg equilibrium. The frequencies of the 1 and 2 alleles of the Msp I mutation site in the intron 5 of DRD3 gene were found to be 62.5% and 37.5%, respectively. The observed frequencies of the 1-1, 1-2 and 2-2 genotypes were found to be 35%, 55% and 10%, respectively, which met Hardy-Weinberg equilibrium. No linkage disequilibrium was observed between the Bal I and Msp I polymorphism in Guangzhou Hans(chi(2)=0165, P>0.05). The frequencies of the T and C alleles of the T978C mutation site of DRD5 gene were found to be 51% and 49%, respectively. The observed frequencies of the T/T, T/C and C/C genotypes were found to be 23.6%, 54.6% and 21.8%, respectively, which met Hardy-Weinberg equilibrium. CONCLUSION: The polymorphisms of DRD2, DRD3, DRD5 gene in Guangzhou Hans were high and different from those in other populations.

Adult↗
PubMed2000

Analysis of DYS19 and DYS287 polymorphisms in the Han population and three other ethnic groups of northeast China.

The allelic distribution of the Y-chromosome specific microsatellite DYS19 in the Han population and in the Daur, Oroqen and Ewenki ethnic groups (Northeast China) was analyzed by PCR and denatured polyacrylamide gel electrophoresis. The allelic distribution in the Han population group is as follows: A = 2.90%, B = 26.09%, C = 26.09%, D = 29.98%, E = 15.94%. This allelic distribution differs statistically significant from that observed in the three other ethnic groups (p < 0.05). Furthermore the polymorphism of the Y-chromosome specific Alu insert sequence DYS287 was tested in these four groups. However, no Alu sequence insert was found.

Alleles↗
PubMed2000

Modulation of hepatic lipoprotein synthesis and secretion by taxifolin, a plant flavonoid.

In the present study, the effects of taxifolin, a plant flavonoid, on lipid, apolipoprotein B (apoB), and apolipoprotein A-I (apoA-I) synthesis and secretion were determined in HepG2 cells. Pretreatment of cells with (+/-)-taxifolin led to an inhibition of cholesterol synthesis in a dose- and time-dependent manner, with an 86 +/- 3% inhibition at 200 microM observed within 24 h. As to the mechanism underlying this inhibitory effect, taxifolin was shown to inhibit the activity of HMG-CoA reductase by 47 +/- 7%. In addition, cellular cholesterol esterification, and triacylglycerol and phospholipid syntheses, were also significantly suppressed in the presence of taxifolin. ApoA-I and apoB synthesis and secretion were then studied by pulse-chase experiments. ApoA-I secretion was found to increase by 36 +/- 10%. In contrast, an average reduction of 61 +/- 8% in labeled apoB in the medium was apparent with taxifolin. This effect on secretion appeared not to be exerted at the transcriptional level. Rather, the effect on apoB secretion was found to be exerted in the early stages of apoB degradation and to be sensitive to dithiothreitol (DTT) and insensitive to N-acetyl-leucyl-leucyl-norleucinal, suggesting a proteolytic pathway involving a DTT-sensitive protease. Fractionation of secreted apoB revealed a slight shift in the distribution of secreted apoB-containing lipoproteins. Cholesteryl ester, rather than triacylglycerol, was shown to be the lipid that primarily regulated apoB secretion. In summary, our data suggest that taxifolin decreases hepatic lipid synthesis with a concomitant decrease and increase in apoB and apoA-I secretion, respectively.

Anticholesteremic Agents↗
PubMed2000

[Experiment study of auto-cartilage engineering].

OBJECTIVE: To engineer diversified shapes of neocartilage from auto-cartilage and provide a new method to reconstruct cartilage. METHODS: Cartilage obtained from the ear of 5-week-old New Zealand rabbits was cut into pieces of 0.5 mm x 0.5 mm, which were seeded onto the three-dimensional polylactic acid foams. The cartilage-polymer construct was implanted into a subcutaneous pocket of the donor rabbit. Animals were sacrificed at 3rd, 6th month after implantation. The retrieved implants in each animal were used for gross measurement and histological analysis. RESULTS: Gross examinations of the specimens at 6 months after implantation revealed that there was neocartilage formation; the maxim size was 8 mm x 8 mm. The cartilage showed no signs of resorption. Histological evaluation confirmed the generation of cartilage. The polymer substrate support cell proliferation. The extracellular matrix stained strongly positive for S-GAGs with Alcian blue staining. CONCLUSION: Neocartilage can be created using free auto-cartilage transplantation on appropriate polymer templates.

Animals↗
PubMed2000

Distraction osteogenesis in functional reconstruction of mandible--report of 6 cases.

OBJECTIVE: To study the application of distraction osteogenesis in mandibular function reconstruction. METHODS: Three types of mandibular distractors were used in 6 patients with different mandibular defects due to tumor resection. For 2 cases with ramus defects, specially designed distractors were used to restore the normal height of the ramus. In 1 case, the trifoci distraction principle was used and a trifoci distractor was designed. In 3 cases, vertical distractors made in Germany or China were used. The patient average age was 31.5 years old (ages ranged from 8 to 54). RESULTS: In 5 cases the mandibular lengthenings were successful according to the direction and distance chosen before distraction. In 1 case, the trifoci distraction principle was applied and a proximal 23 mm mandibular defect was successfully corrected; however, the 23 mm distal mandibular defect was not corrected because the screws for fixation of the transport block were loosened. Infection and dysosteogenesis did not occur in any cases. CONCLUSION: Distraction osteogenesis can successfully be used in mandibular functional reconstruction and is more advantageous than traditional techniques. The most favorable time for distraction osteogenesis in mandibular reconstruction is at the time of tumor resection.

Adult↗
PubMed2000

[Study of differential expressed genes in vascular endothelial cell line ECV304 induced by low density lipoprotein].

OBJECTIVE: To isolate and clone the differential expressed genes induced by atherogenic factors on vascular endothelium and to understand the molecular mechanism of atherosclerosis. METHODS: The differential display reverse transcription PCR method (DDRT-PCR) was used to analyze the differential expressed cDNA in ECV304 induced by low density lipoprotein (LDL). After sequencing and homology research, the differential expressed cDNA fragments were confirmed by northern blot analysis. RESULTS: Up-regulated and down-regulated cDNAs fragments were isolated in ECV304. It was found that some cDNAs fragments were highly homologous to the known human genes, while others were fragments of novel genes. The known up-regulated genes included human 10 kD protein, FGFR1 oncogene partner, intercellular adhesion molecular-1, FK506 binding protein and rTS beta genes. The known down-regulated genes included human fb19, Apobec1-binding protein 1 and RBP2. The expression levels of different genes varied by 70%-200%. CONCLUSION: By DDRT-PCR method, our results showed that LDL could change the expression of many genes in endothelial cells. The high expression level of ICAM-1 in the endothelial cells stimulated by LDL suggested that ICAM-1 is an important adhesion molecular in atherogenesis. The down-regulated expression of Apobec 1-binding protein 1 may affect the cellular synthesis of apolipoprotein. The high expression level of FGFR1 oncogene partner is likely related to the differentiation of ECV304. The function of other differential expressed genes remains to be elucidated.

Cells, Cultured↗
PubMed2000

[Detection of Japanese encephalitis virus in samples of JE patients by RT-PCR].

OBJECTIVE: To set up and assess the feasibility of RT-PCR method for Japanese encephalitis virus (JEV) detection, and use this method to detect clinical specimens. METHODS: The sensitivity of this RT-PCR was measured by plaque formation test, and the specificity of primers was proved by detecting some other flaviviruses. This RT-PCR was also compared with PRHI. RESULTS: JEV RNA could be detected successfully from viral culturing supernatants and from mouse brain infected by JEV. Its sensitivity of detecting JEV RNA from viral culturing supernatants was 64 PFU. A total of 38 specimens (of which 25 were serum specimens, 13 CSF specimens) from 16 clinically susceptible JE patients were examined by RT-PCR and RPHI Summing up the detection results of RT-PCR and RPHI, 14 patients among the 16 susceptible patients were affirmed as Japanese encephalitis patients. This RT-PCR is specific to JEV. The sensitivity of joint use of RT-PCR and RPHI to detect JEV was 100%, higher than using RPHI alone, and was 7.7% higher than using RT-PCR only. RT-PCR is more suitable for epidemiological survey than virus isolation. CONCLUSIONS: This RT-PCR for JEV detection is highly specific and sensitive. Toxemia period of JE patient is very short, so grasping the time of blood specimen collection will affect virus detection rate.

Encephalitis Virus, Japanese↗
PubMed2000

[The effects of PDGF-AB on pro alpha 1 (III). mRNA expression of fibroblasts].

OBJECTIVE: To investigate the mechanism of PDGF-AB to promote wound healing and its role during the process of scar formation. METHODS: In vitro cultured fibroblasts of human normal skin and hypertrophic scar were treated with PDGF-AB. The expression of Pro alpha 1 (III) mRNA of the fibroblasts was evaluated by in situ hybridization technique. RESULTS: PDGF-AB could increase Pro alpha 1 (III) mRNA expression of fibroblasts of both normal skin and hypertrophic scar in a dose-dependent manner. However, the effect of PDGF-AB on hypertrophic scar fibroblasts was stronger. CONCLUSIONS: PDGF-AB may promote wound healing by stimulating extracellular matrix synthesis, e.g. collagen. PDGF-AB may also play a role in scar formation through collagen deposition.

Biomarkers↗
PubMed2000

[Correlation of photoplankton and its environmental factors in Rushan Bay].

The relationship between photoplankton and its environmental factors in Rushan Bay was studied from June to September, 1995. The result shows that there existed a negative correlation between the number of photoplankton and the content of inorganic nutrients. The correlation coefficients for inorganic nitrogen and phosphorus were -0.67 and -0.80, respectively. The dissolved oxygen and chlorophyll-a were positively correlated to photoplankton, and their correlation coefficients were 0.92 and 0.85 respectively. Based on N/P analysis, the content of inorganic nitrogen was relatively short to the reproductive growth of photoplankton during experimental months, except for the last ten days of August.

China↗
PubMed2000

[Structure and spatial pattern dynamics of dominant populations in a natural forest in north Guangdong Province].

Five 1000-m2 plots were set up in a forest dominated by Schima superba, Castanopsis fargesii and Pinus massoniana in Luoba Nature Reserve, Shixing County, north Guangdong Province. Field data were obtained by tally with contiguous grid quadrat method. The analysis of population structure and spatial distribution patterns of the dominant species in the forest shows that S. superba and C. fargesii had a large reserve of seedlings, with up to 1538 and 9763 seedlings per hm2, respectively, showing a pyramid shape of population structure. Both populations had a high mortality for seedlings of classes I and II in the process of development to saplings. The population structure of P. massoniana was an inverse pyramid type, with no seedlings and only 4 saplings per hm2, but 44 large trees per hm2. The spatial distribution patterns of P. massoniana and C. fargesii in coniferous broadleaved mixed community chiefly dominated by broadleaved trees were uniform, and in those chiefly dominated by P. massoniana were aggregated, but there were different causes of pattern dynamics for P. massoniana and C. fargesii. S. superba in both communities showed an aggregated distribution pattern. The aggregation intensity was different, with K values from 0.4280 to 0.9750. Regarding the distribution patterns in different development stages, S. superba was aggregated in different stages, while C. fargesii varied with uniform distribution pattern for the large trees and aggregated distribution pattern for the saplings and median trees. As for P. massoniana, its median trees showed an aggregated distribution pattern, while both the saplings and large trees were uniform. The variations in spatial distribution patterns of populations in different development stages were closely related to the biological and ecological characteristics of the species, but different block size had an impact on the outcome of spatial distribution patterns.

China↗
PubMed2000

[A preliminary study on influence of N and P on population constituent of planktonic diatoms in seawater].

Experiment was conducted to study the influence of N and P on population constiuent of planktonic diatoms in seawater. The concentrations of N and P and their ratios might significantly affect the population constituent of planktonic diatoms in seawater, the more the concentrations of N and P and the bigger the N/P ratio to Redfield ratio, the less the species of planktonic diatoms and Shannon's index. The experimental result was verified in the investigation from shrimp culturing ponds.

Animals↗
PubMed2000

[Expression of telomerase and its RNA in nasopharyngeal carcinoma].

OBJECTIVE: To study the activity of telomerase and the expression of its RNA in nasopharyneal carcinoma (NPC) and HNE1 cell lines of NPC. METHODS: Telomerase activity was detected with telomeric repeat amplification protocol (TRAP) PCR ELISA kit in 41 cases of NPC, 14 cases of tissues adjacent to the carcinoma, and 19 cases of chronic nasopharyngitis, HNE1 cell lines of NPC, HL60 cell lines of leukemia, TUL1 cell lines of lung cancer, as well as three other kinds of normal control cells. The sensitivity and specificity of telomerase assay were also analyzed. Moreover, the expression of human telomerase RNA (hTR) was studied in 27 cases of NPC, 19 cases of adjacent nasopharyngeal tissues, and 17 cases of control groups by RT-nested PCR. RESULTS: The telomerase activity was found increased in NPC and in tissues adjacent to NPC with absorbance value (A value) of 1.15 U +/- 0.78 U and 1.04 U +/- 0.67 U respectively, compared with chronic nasopharyngitis (A = 0.18 U +/- 0.09 U). In NPC with cervical lymphnodes involvement the telomerase activity (A = 1.25 U +/- 0.79 U) was higher than in those without involvement (A = 1.02 U +/- 0.71 U), P < 0.05. The telomerase activity was also observed in HNE1 cell lines (A = 1.26 U +/- 0.97 U) and in other two kinds of cancer cell lines, but not in the three kinds of normal control cells. By contrast, no significant difference was seen in the expression of hTR among the three nasopharyngeal biopsy groups (P > 0.05). Finally, the sensitivity of telomerase assay was high (at an amount of 10(2) HNE1 cells), and the specificity was also high (after inactivation by heat or RNase, the telomerase activity was very low). CONCLUSIONS: A high frequency of telomerase activity is commonly seen in NPC, adjacent nasopharyngeal tissues, and HNE1 cell lines and is closely associated with NPC with cervical lymphnodes involvement. Both sensitivity and specificity of the telomerase assay are high. However, owing to the fact that the expression of hTR has no obvious difference between NPC and normal tissues and does not always correspond with the telomerase activity, it would be better to do TRAP as well as hTR assays for the activity and expression in assessing the carcinogenesis of NPC. So, more intensive study on the role of hTR in the carcinogenesis of NPC and on the exact relationship between hTR and telomerase is needed.

Adult↗
PubMed2000

Detecting residual ischemia and identifying coronary artery disease after myocardial infarction using dobutamine technetium-99m-MIBI SPECT.

OBJECTIVE: To evaluate dobutamine technetium-99m methoxy isobutyl nitrile (sestamibi) single-photon emission computed tomography (Dobu-ECT) in detecting residual ischemia and identifying coronary vessel disease after myocardial infarction. METHODS: Sixty-two patients with confirmed myocardial infarction were studied with Dobu-ECT at the time of coronary artery angiography. Dobutamine was administered intravenously in incremental rates from 5 to 40 micrograms.kg-1.min-1 at 3-minute intervals. At the highest infusion rate, 7.4 x 10(8) Bq 99mTc-MIBI was injected intravenously, and tomographic imaging was performed after one hour. Resting images were taken after 24 hours, with a second dose of 99mTc-MIBI. RESULTS: The sensitivity of Dobu-ECT in detecting residual ischemia of myocardial infarction was 76%, which was higher than dobutamine electrocardiography (Dobu-ECG). Regardless of the single-, double- or triple-vessel diseases, Dobu-ECT was superior to Dobu-ECG in identifying residual ischemia (56% vs 4%, 86% vs 27%, 100% vs 47%, P < 0.01, respectively). The incidence of residual ischemia in patients receiving thrombolytic therapy was 67%, lower than patients without thrombolysis (72%) or those with an old myocardial infarction (94%). But the differences were not statistically significant. Dobu-ECT detected only 56% of ischemias in non-infarct related myocardium. Eighty-two percent of all significantly stenosed vessels were detected with Dobu-ECT, and 84% of patients with multivessel disease could be accurately identified. The sensitivity of Dobu-ECT was significantly greater for detecting severe stenosis over moderate stenosis. The sensitivity for detecting stenosis in the right coronary artery was greater than left anterior descending or left circumflex, but its specificity was lower. CONCLUSION: Dobu-ECT can identify residual ischemia, as well as its location and extent after myocardial infarction. Dobu-ECT can also accurately detect significantly stenosed vessels.

Adult↗