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Biomedical subjects

B Zhang

Publications and source records attributed to B Zhang.

At least 253 records · Page 14Linked to original sources
PubMed2000

[Modified total cavopulmonary connection for treating patients with functional single ventricle].

OBJECTIVE: To modify the classic procedure for better surgical results of total cavopulmonary connection (TCPC). METHODS: Modified TCPC was performed in 13 patients with functional single ventricle. In the modified TCPC procedure, the distal end of the superior vena cava (SVC) was connected with the upper edge of the right pulmonary artery (RPA) with the anastomosis orifice near the left side, and the proximal end with the lower edge of RPA with the anastomosis orifice near the right side. Among them, intra-atrial tunnel was established with a partial tube of PTFE using the lateral tunnel technique in 8 patients, and the distal end of the inferior vena cava (IVC) was directly connected with the lower edge of RPA using extracardiac conduit in the beating heart in 5. RESULTS: One patient (7.7%) died early. Twelve patients survived and had the SatO(2) (94.6 +/- 1.2)% postoperatively while inspiring air. Angiography showed that most blood from IVC enters the right lung and most blood from SVC the left lung. No late mortality was seen during the follow up for 6 months to 2 years and 2 months. NYHA class I was noted in 10 patients and class II in 2. Echocardiography showed that left ventricular volume reduced significantly and ventricular function was normal. CONCLUSIONS: Modified TCPC produces optimal blood flow between the two lungs, elevates postoperative Sat O(2) effectively, decreases ventricular volume load and improves ventricular functions.

Adolescent↗
PubMed2000

[Surgical correction of complete atrioventricular septal defect with tetralogy of Fallot].

OBJECTIVE: To report the surgical correction of complete atrioventricular septal defect with tetralogy of Fallot (AVSD-TOF). METHODS: Six consecutive patients aged 3 - 9 years underwent correction of complete AVSD-TOF. The two-patch technique for atrioventricular septal defect was used. The ventricular septal defect was closed through a right ventriculotomy and right atriotomy in each case. The commissure between the superior and inferior bridging leaflets of the left portion of the common atrioventricular valve was closed in each patient. RVOT obstruction was relieved by a transannular autologous pericardium with monocuspid valve. RESULTS: Postoperative complications included respiratory failure in 1 patient, low cardiac output syndrome in 1, and MOF in 1. There was one mortality because of MOF in the early postoperative period. Five survivors were followed up from 6 months to 5.5 years (mean 2.3 years). There was no late mortality and only one patient had mild left atrioventricular valve regurgitation. NYHA cardiac function was class I in 4 patients and class II in 1. CONCLUSIONS: AVSD-TOF can be corrected using the two-patch technique and closure of the ventricular septal defect through a combined approach using a right ventriculotomy and right atriotomy. Routine closure of the commissure of the left portion of the atrioventricular valve results in a low incidence of regurgitation. Good functional result can be achieved in most patients postoperatively.

Cardiac Surgical Procedures↗
PubMed2000

[Effect of protein expression on antisense c-myc and PCNA for vascular smooth muscle cells].

OBJECTIVE: To study the methods of inhibiting proliferation of vascular smooth muscle cells (VSMCs), we observed the change of protein expression after using antisense c-myc, PCNA for VSMCs. METHODS: The sense, antisense, and mismatched oligomers for c-myc or PCNA were individually delivered to the cultured VSMCs. Using Western blot, immunohistochemistry assay and image analysis system, we observed the change of c-myc and PCNA protein expression in the VSMCs. RESULTS: Antisense c-myc, PCNA at concentration of 10 micromol/L can successfully inhibit the expression of c-myc, PCNA protein in the VSMCs (P < 0.05), but the sense and the mismatched do not have this effect (P > 0.05). CONCLUSION: The data suggested that the antisense c-myc, PCNA could attenuate the protein expression of c-myc, PCNA, and it is an effective method for the inhibition of VSMCs hyperplasia.

Blotting, Western↗
PubMed2000

[The growth inhibitory effects by transfection of p16 gene on human pancreatic cancer cell line].

OBJECTIVE: To elevate the growth inhibitory effects by transfection of p16 gene on human pancreatic cancer cell line JF305. METHODS: Recombinant eukaryotic expression vector pDOR-p16 containing exogenous human wt-p16 cDNA and vector containing neomycin resistance gene only were introduced by Liposomes-mediated gene transfection into JF305 cell line which did not express endogenous p16. By using PCR amplification, in situ hybridization, and immunocytochemistry, the clones obtained were detected for efficiency of transfection and effect of vector expression and observed for the changes of their biologic characteristics. RESULTS: Exogenous wt-p16 was successfully transferred into JF305 cells and obtained permanent expression. The growth rate of these transfected JF305 cells in regular medium and soft agar was inhibited. The percentage of phage G(1) cells increased and that of phage S cells decreased by analysing cell cycle. The ultrastructural changes of the cells observed under electron-microscope revealed growth retardation. CONCLUSION: p16 is a candidate for cancer gene replacement therapy of human pancreatic cancer.

Cell Division↗
PubMed2000

[E-selectin and its ligand-sLeX in the metastasis of hepatocellular carcinoma].

OBJECTIVE: To study the significance of E-selectin and its ligand-sLeX in the metastasis of hepatocellular carcinoma (HCC). METHODS: Flow cytometry and immunohistochemistry were used to detect the expression of E-selectin and its ligand-sLeX in HCC cell lines and in human HCC tissues. RESULTS: The positive rate of E-selectin in vascular endothelial cells adjacent to cancer nest in tumors was 67.9% (19/28). In tumors accompanied with emboli or satellite foci, it was significantly higher than that without emboli or satellite foci (P < 0.05). The positive rate of E-selectin was not related to tumor size, tumor capsule, AFP, and the degree of differentiation. The positive expressions of sLeX in SMMU-7721, PLC/PRF/5 and HepGII cell lines were 7.03%, 63.35% and 97.29% respectively. The positive cells of sLeX were mainly distributed in the margin of tumors; the positive expression of sLeX in HCC cells in emboli or invasive tumor tissues was much higher than that in primary foci. CONCLUSION: E-selectin and its ligand-sLeX are closely correlated with the metastasis of HCC.

Adult↗
PubMed2000

[Distribution of HIV resistance CCR5-delta 32, CCR2-64 I and SDF1-3'A alleles and their polymorphisms in the Han population in China].

OBJECTIVE: To study the frequency and polymorphism of three mutations (CCR5(Delta)32, CCR2-64I and SDF1-3'A alleles) conferring resistance to determined HIV-1/AIDS in the indigenous Han population in China. METHODS: The study population included 1,267 subjects, of which consisted 98.7% (1,251/1,267) Han people. The genotypes of the three mutations were respectively, detected by polymerase chain reaction (PCR) for CCR5(Delta)32 mutation, or by PCR/RFLP (restriction fragment length polymorphism) assay with the digestion of restriction endonuclease Bsa BI and Msp I for CCR2-64I and SDF1-3'A mutations. DNA sequencing was employed to confirm the accuracy of PCR or PCR/RFLP products. RESULTS: The frequency of the mutant alleles were: 0.00119 for CCR5(Delta)32; 0.20023 for CCR2-64I, and 0.28723 for SDF1-3'A. The three heterozygous CCR5-wt/Delta32 mutants were identified and no homozygotes were detected in indigenous Han population. The frequencies of CCR2-64I and SDF1-3'A alleles in China were higher than those of Caucasians descents in the USA and Europe. CONCLUSION: Our data was the first findings on the frequency and polymorphism of CCR5(Delta)32, CCR2-64I and SDF1-3'A alleles in indigenous Han population in China which implied that the indigenous Han people might have a higher genetic susceptibility to the infection of sexually transmitted HIV-1 (R-5) strain. Further study is needed to clarify the significance of higher frequency of CCR2-64I and SDF1-3'A alleles in Han population.

Alleles↗
PubMed2000

[Expression of telomerase genes in human tumors].

OBJECTIVE: To investigate the correlation between the expression of telomerase genes and malignant phenotypes of human tumors and to compare the expression of telomerase genes and its activity reported in order to evaluate the role of detection of telomerase genes in tumor diagnosis. METHODS: With in situ hybridization, the expression and distribution of telomerase hTR and hTRT genes were observed in 78 cases of human cancer tissues, 20 cases of precancerous lesions and 28 of benign lesions. The results were statistically analyzed. RESULTS: hTR and hTRT were detected in 85% (66/78) and 82% (64/78) of the primary cancers. While in the adjacent tissues, the positive rates were only 3% (2/78) and 5% (4/78). In 20 precancerous cases, the positive rate for hTR and hTRT were 20% (4/20) and 15% (3/20) and the positive cases in 28 benign lesions were 0 and 1/28 (4%), respectively. The positive detection of hTR and hTRT expression in cancer group were significantly different from those in the adjacent tissues, precancerous cases and benign lesion group (P < 0.01). In analysing main types of the human cancers, the positive frequency of hTR and hTRT were 94% (15/16) and 88% (14/16) for the breast cancer, 85% (17/20) and 90% (18/20) for the colon cancer, 80% (8/10) and 80% (8/10) for the gallbladder cancer, 75% (6/8) and 75% (6/8) for the lung cancer, 75% (6/8) and 75% (6/8) for the stomach cancer, and 83% (5/6) and 83% (5/6) for the esophagus cancer, respectively. The expression level of telomerase hTR and hTRT correlated well with the malignancy and metastatic potentials in breast cancer, colon cancer and bladder cancer. Besides, the expressions of hTR and hTRT were noticed to be also highly correlated (P < 0.01). CONCLUSIONS: The expression of telomerase genes correlates with tumor malignant phenotypes, and may reflect the progression of tumors, and the detection of telomerase gene expression may be useful in a retrospective cancer research. It is worthwhile for further study to clarify whether screening of telomerase gene expression is able to become a new index for tumor diagnosis and prognosis.

Breast Neoplasms↗
PubMed2000

[The effects of cyclin E on the growth and other cell cycle related genes of breast carcinoma cells MCF-7].

OBJECTIVE: To investigate the effects of cyclin E in high and low expression on the cell growth and other cell cycle associated genes of MCF-7 cells. METHODS: Eukaryotic expression vehicles of sense and antisense cyclin E were constructed and transferred into the MCF-7 cell line using lipofectAMINE. The integration and expression of cyclin E were conformed by Southern and Western blot. The cells growth was observed and the changes in cell cycle were analyzed by flow cytometry. The expression of other cell cycle associated genes was assayed using Western blot. RESULTS: A high expression of cyclin E enabled to promote the cell growth and DNA synthesis and accelerated the proceeding of G(1) phase to S phase, It also promoted the phosphorylatin of pRB and up-regulate the expression of p27 while a low expression of cyclin E showed an opposite effect. CONCLUSION: Different expression of cyclin E enables to affect growth of MCF-7 cell by the changes of cell cycle related genes.

Breast Neoplasms↗
PubMed2000

[Role of paraventricular nucleus in natriuresis and diuresis induced by volume expansion in rabbits].

In sham-lesioned and paraventricular nucleus (PVN) lesioned rabbits, the peak increases of urine volume (UV) induced by volume expansion (VE) were 0.59+/-0.09 and 0.31+/-0.03 ml/min (P<0.01) respectively, whereas the peak increases of U(Na)V were respectively 66.76+/-6.74 and 36.05+/-3.44 micromol/min (P<0.01). No significant differences were found in the two increases induced by VE between rabbits with intact and those with sham-lesioned PVN. In rabbits with vagotomy there were no changes in the two increases after PVN lesion (P>0.05). In rabbits with renal denervation there was no significant change in natriuretic response after PVN lesion (P>0.05), but lesion of PVN significantly attenuated diuretic response (P<0.02). There were no significant differences in glomerular filtration rate (GFR) and renal plasma flow (RPF) before or after VE between the rabbits with intact and lesioned PVN (P>0.05). These results suggest that PVN is involved in the regulation of natriuresis and diuresis induced by VE, which are mediated by vagal afferent nerve, whereas the renal sympathetic efferent nerve may be involved in natriuretic response.

Animals↗
PubMed2000

[Three-dimensional finite element analysis of all-ceramic crowns of the posterior teeth].

The all-ceramic crown has been applied in clinical practice for its esthetic value and excellent biocompatibility. The purpose of this study was to examine the effect of different cervical marginal shapes on the stress distribution of all-ceramic crowns of the mandibular first molar by three-dimensional finite element analysis. The results showed that under vertical loading, the bearing compress stress on the occlusal region, the tensile stress concentration were observed at buccal cervical marginal of all-ceramic crowns; the stress at the surface of the crown was the highest, the stress inside the crown was higher than that inside the prepared teeth; the shoulder's stress value was lower than the chamfer's. These results lay the theoretic foundation for clinical application of all-ceramic crown, suggesting that the shoulder design should be recommended in clinical practice when the all-ceramic crowns are planned. The cervical thickness of the crown should be within 0.5-1.0 mm, and the crowns surface should be polished well to improve its resistance to fracture.

Ceramics↗
PubMed2000

[Cloning and expression of metallothionein gene of Bombyx mori].

Yeast MTI gene from vector pCMI-1 was used as a probe. It appeared strong hybridization signals when the total DNA of Bombyx mori Huishu eggs hybridizes with the probe. The 1-6 kb DNA fragments were isolated from the EcoR I digested total DNA of Bombyx mori Huishu eggs and ligated with M13- vector digested by restriction EcoR I. The ligation mixtures were used to transform E. coli DH5 alpha. blue/White colonies selection was used to identify colonies with insert. Approximately 4000 white colonies were selected, so the part genomic library of Bombyx mori was constructed. Three positive colonies were gained from the genomic library by southern blotting analysis, designated T1 (pZHC-1), T5 (pZHC-5), T7 (pZHC-7). Digesting the recombinant plasmid pZHC-5 with 12 restriction enzymes, the results suggested that the inserted fragment was about 1.2 kb and there was only a Hind III site. The experiment of resistant to CuSO4 proved that the DH5 alpha cells contain recombinant plasmids were more resistance than the recepient DH5 alpha cells. According to these results, the inserted fragment possibly contains the gene encoding Metallothionein of Bombyx mori. The sequence analysis of the inserted fragment and its high-expressions in E. coli are in progress.

Animals↗
PubMed2000

[A Chinese herbal compound induces neurotrophy in astrocyte by a new study method called "cerebrospinal fluid pharmacology in Chinese materia medica"].

OBJECTIVE: To find a effective method by which the potency of Chinese materia medica (CMM) on the central nervous system (CNS) could be correctly investigated. METHOD: The cerebrospinal fluid(CSF) and serum after oral CMM 1 to 1.5 hours was gained and then added into the astrocyte cell culture medium. After 48 h, the above medium was in proportion transferred to the neuron culture medium. Typan blue staining, LDH and MTT test were utilized to observe the drug effect on the neuron survival. RESULTS: The serum, but not the CSF, showed the toxicity on the astrocyte. MTT test on the neuron survival showed that the OD492nm value in the CMM group was higher than the other groups (P < 0.05). The astrocyte medium stimulated by the CSF including CMM could promote the neuron axon growth. CONCLUSION: If observing the CMM potency on CNS in vitro, the CSF was better than the serum, we called it "Cerebrospinal Fluid Pharmacology in Chinese Materia Medica". Furthermore, the CMM could induce the neurotrophy of astrocyte.

Animals↗
PubMed2000

[Pedicled galeal flap in the reconstruction of head and neck tumor defects].

OBJECTIVE: To evaluate the advantage and applications of pedicled galeal flap in head and neck region. METHODS: A consecutive series of 17 patients underwent surgical reconstruction with pedicled galeal flaps after head and neck tumor resection. The defects included nasopharynx, skull base, maxilla, orbital base, oropharynx and oral cavity and the size ranged from 5 cm x 5 cm to 10 cm x 10 cm. The technique for using this flap was described and application was illustrated with 3 case reports. RESULTS: Complete success of galeal flaps for the reconstruction of head and neck defects was achieved in 13 of the 17 cases (76.5%) and partial necrosis was observed in the remaining 4 cases (23.4%). Immediate wound complications occurred in four cases, which resolved spontaneously. Four delayed complications were observed in 4 of 9 survival cases that included trismus (3) and alopecia (1). CONCLUSION: Galeal flap is a thin, pliable and well vascularised reconstruction tissue and is highly reliable. The donor site morbidity is minor. We have found the flap to be useful in the reconstruction of a variety of defects in head and neck, especially in skull base, orbital base, nasopharynx and oropharynx.

Adolescent↗
PubMed2000

[Assay and L1 gene sequence analysis of human papillomavirus type 6 and 11 in condylomata acuminata].

OBJECTIVE: To determinate the prevalence of HPV type 6, 11 in condylomata acuminata, and analyze the sequence of L1 gene and its deduced L1 protein. METHODS: PCR was used to amplify DNA sequences between E6 and E7 of HPV type 6 and 11. The PCR products were identified by the fragment length cleaved with restriction enzyme RsaI. L1 genes were amplified with high fidelity Taq, and cloned DNA sequences were detected by the dideoxynucleotide method. RESULTS: In 34 examples of condylomata acuminata, HPV11 was found in 25 examples (73.5%), HPV6 in 15(44.1%), including HPV6 + HPV11 in 6(17.6%). In comparison with the prototypes there were 7-8 point mutations in HPV11 L1 gene and 3 in HPV6L1 gene. L1 encoded protein changes showed up only in 1-3 amino acids in the former cases. CONCLUSION: Most of patients tested with condylomata acuminata are mainly infected by HPV11, the rest of them by HPV6 or by co-infection of two mixex types. Sequence analysis of L1 genes indicated that mutations were found in both HPV6 and 11, whereas deduced amino acid mutations in L1 protein were limited in HPV11 only.

Adult↗
PubMed2000

[Epidemiological characteristics of Guillain-Barré syndrome in urban and rural areas in Beijing and Hebei, China].

OBJECTIVE: To investigate epidemiological and clinical patterns of Guillain-Barré syndrome (GBS) in urban and rural areas in Beijing municipality and Hebei province, China. METHODS: We investigated GBS incidence using a strengthened case surveillance and an active case ascertainment in 2 counties and 4 districts of Beijing municipality and 3 counties of Hebei province during 1993 to 1994. RESULTS: On the basis of the diagnostic criteria of NINCDS, 54 patients were identified. The age-adjusted incidence rates per 100,000 population for GBS were 0.9 in rural areas, and 0.8 in urban areas. A peak agespecific incidence showed in adults aged 50 to 59 years. A higher incidence appeared to occur in the spring and summer for rural residents, but not significant for urban population. In comparing course of GBS in rural and urban areas, there were differences in mean days from beginning of neurological symptom to maximal weakness (4.3 vs 7.6 days), and from symptom onset to beginning of recession (11.8 vs 17.5 days). There were preceding events in 72% patients, most frequently in respiratory infection, sensory disturbance in 70.9%, and respiratory assistance in 7.6%. The outcome was compatible with other reports; with complete recovery at 12 months in 79.2% and minimal residua in 20.8% for those alive and with casefatality rate in 7.4%. In addition, a follow-up study on electrophysiological features in 19(90.5%) patients from two counties of Beijing showed the demyelinating lesion (89.5%) over the axonal lesion (52.6%) of motor and/or sensory nerves. CONCLUSIONS: The epidemiological and clinical characteristics of GBS were similar to that reported in other countries. Demyelinating GBS was the main pattern in present population-based study.

Adolescent↗
PubMed2000

Molecular cloning of hTRT catalytic domain from HeLa cells and its expression in E. coli and purification.

OBJECTIVE: To investigate the expression of telomerase gene hTRT mRNA in HeLa cells and to obtain hTRT protein for further study. METHODS: The gene for encoding hTRT catalytic domain was cloned based on RT-PCR amplification from HeLa cells and sequenced. The cloned hTRTcDNA was in-frame inserted into His-tag fusion expression vector pEK318. The His-tag hTRT fusion protein were purified by Ni-NTA chromatography and stained by western blotting. RESULTS: An approximately 620bp fragment was generated and cloned into pBluescript SK + between SaII and BamHI sites. DNA sequencing showed the isolated fragment was consistent to those reported. SDS-PAGE present that a 17kDa protein was expressed stably in E. coli JM109 harboring pEKTRT344 containing 6 x His-tag and hTRT 150aa, and the expression level of the protein was about 26% of the total bacterial proteins, while the expression of pEKTRT containing 6 x His-tag and hTRT 243aa was only detectable as 27 kDa band in western blotting. Both of fusion proteins were purified by Ni-NTA chromatography and showed single band( > 95% purifity) in Coomassie Brilliant staininng. Western-blotting confirmed that two proteins could be recognized by the Ni-NTA AP conjugate. CONCLUSIONS: The hTRT catalytic domain was highly conserved. The expressed hTRT protein contained recognizable His-tag, telomerase-specific and strong antigenic epitops, which may be convenient for further investigation.

Catalytic Domain↗