Biomedical subjects

Z Chen

Publications and source records attributed to Z Chen.

At least 271 records · Page 15Linked to original sources

PubMed2001

Intravascular local gene transfer mediated by protein-coated metallic stent.

OBJECTIVE: To assess the feasibility, efficiency and selectivity of adenovirus-mediated gene transfer to local arterial wall by protein-coated metallic stent. METHODS: A replication-defective recombinant adenovirus carrying the Lac Z reporter gene for nuclear-specific beta-galactosidase (Ad-beta gal) was used in this study. The coating for metallic stent was made by immersing it in a gelatin solution containing crosslinker. The coated stents were mounted on a 4.0 or 3.0 mm percutaneous transluminal coronary angioplasty (PTCA) balloon and submersed into a high-titer Ad-beta gal viral stock (2 x 10(10) pfu/ml) for 3 min, and then implanted into the carotid arteries in 4 mini-swines and into the left anterior descending branch of the coronary artery in 2 mini-swines via 8F large lumen guiding catheters. The animals were sacrificed 7 (n = 4), 14 (n = 1) and 21 (n = 1) days after implantation, respectively. The beta-galactosidase expression was assessed by X-gal staining. RESULTS: The results showed that the expression of transgene was detected in all animal. In 1 of carotid artery with an intact intima, the beta-gal expression was limited to endothelial cells. In vessels with denuded endothelium, gene expression was found in the sub-intima, media and adventitia. The transfection efficiency of medial smooth muscle cells was 38.6%. In 2 animals sacrificed 7 days after transfection, a microscopic examination of X-gal-stained samples did not show evidence of transfection in remote organs and arterial segments adjacent to the treated arterial site. CONCLUSIONS: Adenovirus-mediated arterial gene transfer to endothelial, smooth muscle cells and adventitia by protein-coated metallic stent is feasible. The transfection efficiency is higher. The coated stent may act as a good carrier of adenovirus-mediated gene transfer and have a potential to prevent restenosis following PTCA.

Adenoviridae↗

PubMed2001

[Quick intraoperative parathormone monitoring].

Successful parathyroidectomy for primary hyperparathyroidism has traditionally consisted of bilateral neck exploration with identification of all parathyroid glands and excision of grossly abnormal glands. Recently it has been reported that preoperative localization combined with intraoperative monitoring of parathyroid hormone enables performing directed unilateral cervical explorations while maintaining similar cure rates. This new surgical approach, feasible under local anesthesia as an outpatient procedure, decreases operative time, improves cosmetic results and may reduce morbidity. We report preliminary results of our experience in implementing this method.

Adult↗

PubMed2001

Cryopreservation of suckling pig hepatocytes.

To determine the best and simplest method for cryopreservation of pig hepatocytes, we compared immediate cryopreservation with cryopreservation after short-term culture. Suckling pig hepatocytes were isolated by a modified 2-step in situ collagenase perfusion method, suspended in serum-free medium, and preserved for 10 da by two cryopreservation methods. Serial measurements were made of cell viability, LDH release, synthesis of protein, urea and glucose, glucose-6-phosphatase (G-6-Pase) activity, and diazepam transformation after thawing. These measurements were performed on both groups of cultured hepatocytes, and on freshly isolated hepatocytes, which served as a control. High viability (>95%)of thawed hepatocytes was obtained and maintained in both cryopreservation groups. There were no significant differences in cell viability, protein synthesis, glucose synthesis, G-6-Pase activity, or diazepam transformation between the two cryopreservation groups. In the immediate cryopreservation group, urea synthesis was less than in the group with cryopreservation after short-term culture. Protein synthesis, glucose synthesis, and diazepam transformation were lower in both cryopreserved groups than in the controls. The results showed that a protocol of immediate cryopreservation of hepatocytes in RPMI-1640 medium containing 10% DMSO, hormones, growth factors, and 10% newborn bovine serum, together with rate-controlled freezing and rapid thawing, provides indices of cell viability and function during subsequent serum-free culture that are comparable to hepatocytes cryopreserved after short-term culture, except for lower urea production. This simple procedure can be used in studies of bioartificial liver and hepatocyte transplantation.

Animals↗

PubMed2001

Molecular genetic profiling of Gleason grade 4/5 prostate cancers compared to benign prostatic hyperplasia.

PURPOSE: Because Gleason grade 4/5 cancer is the primary cause of failure to cure prostate cancer, we examined the molecular profiles of this high grade cancer in search of potentially new therapeutic interventions as well as better serum markers than prostate specific antigen. MATERIALS AND METHODS: We compared the gene expressions in fresh frozen tissues from 9 men with Gleason grade 4/5 cancer to 8 men with benign prostatic hyperplasia (BPH) treated with radical retropubic prostatectomy. Labeled complementary RNA from each of the 17 tissues was applied to HuGeneFL probe arrays representing approximately 6,800 genes (Affymetrix, Inc., Santa Clara, California). After removing all genes undetectable in BPH and grade 4/5 cancers, and transforming the data into a parametric distribution, we chose only those up and down-regulated genes with a p difference in fluorescence between grade 4/5 cancer and BPH of p <0.0005. This value reduced the data set to 40 up-regulated and 111 down-regulated genes. We then eliminated all genes that were not expressed in all 8 BPH and 9 grade 4/5 tissues, which produced a final set of 86 genes, of which 22 were up-regulated and 64 were down-regulated. RESULTS: Cluster analysis cleanly separated men with grade 4/5 cancers from those with BPH. Only 17 of the 86 candidate genes (20%) were known to be prostate cancer related and 42 (49%) were related to other cancers. The most up-regulated gene is Hepsin, a trypsin-like serine protease with its enzyme catalytic domain oriented extracellularly. Prostate specific membrane antigen is the second most up-regulated gene (all other reports on prostate specific membrane antigen have been at the protein level). The genes for prostate specific antigen (hK3) and human glandular kallikrein2 (hK2) showed equivalent expression levels 10 times the average of other genes. Complete lists of all 22 up-regulated genes and 64 down-regulated genes, together with their locus on the chromosome, are presented in rank order. CONCLUSIONS: We characterize for the first time 64 down-regulated and 22 up-regulated genes in Gleason grade 4/5 cancer, using the gene profile from BPH as control tissue. A number of interesting new genes, previously undescribed in prostate cancer, are presented as possibilities for further study.

Aged↗

PubMed2001

Decolorization of Direct Black 22 by Aspergillus ficuum.

The decolorization of Direct Black 22 by Aspergillus ficuum has been studied. It was found that Aspergillus ficuum could effectively decolorize Direct Black 22 especially when grown as pelleted mycelia. Results showed that the media containing Direct Black 22 at 50 mg/L could be decolorized by 98.05% of the initial color in 24 h. The optimum pH and temperature of decolorization are 4.0 and 33 degrees C respectively. Aeration was quite beneficial to decolorization. Medium composition and the concentration of Direct Black 22 could affect the rate of decolorization. The dye degraded products assayed by UV-visible spectrophotometer and macroscopic observation showed that the decolorization of Direct Black 22 by mycelial pellets includes two important processes: bioadsorption and biodegradation. The degradation experiment agree with the Michaelis-Menten kinetics equation.

Aspergillus↗

PubMed2001

Effect of clobenpropit on regional cerebral blood flow in rat hippocampus.

AIM: The effect of clobenpropit on regional cerebral blood flow (rCBF) was investigated in the rat hippocampus. METHODS: rCBF was determined in the hippocampus by the hydrogen clearance method. The blood pressure was measured by a tail-cuff plethysmograph. RESULTS: Intracerebroventricular (icv) injection of clobenpropit (20, 50 microg), a representative H3-antagonist, dose-dependently and significantly increased rCBF in the hippocampus. The increase of rCBF induced by clobenpropit was enhanced by metoprine (1, 2 mg/kg), a selective histamine N-methyltransferase inhibitor; however, was antagonized by an H3-agonist, (R)-alpha-methylhistamine (5 microg), an H(1)-antagonist, mepyramine (5-10 mg/kg), and an H2-antagonist, zolantidine (10 mg/kg). Clobenpropit caused no apparent effects on blood pressure even at a high dose of 50 microg. CONCLUSION: These results suggest that brain endogenous histamine may contribute to increase rCBF in the rat hippocampus via both the post-synaptic H1-, H2-receptors and the pre-synaptic H3-receptor.

Animals↗

PubMed2001

Effect of H1-antagonists on spatial memory deficit evaluated by 8-arm radial maze in rats.

AIM: To evaluate effects of certain H1-antagonists on spatial memory with 8-arm radial maze performance of rats. METHODS: Eight-arm radial maze performance was used to measure spatial memory in rats. RESULTS: Chronic treatments of classical H1-antagonists, diphenhydramine (5 mg/kg) and pyrilamine (20 mg/kg) impaired acquisition memory process regarding both parameters of radial maze performance. In addition, the memory retrieval process was also impaired significantly by a single administration of diphenhydramine (5, 10 mg/kg) and pyrilamine (50 mg/kg). However, the newly developed H1-antagonist, epinastine caused no appreciable effect on both acquisition and retrieval memory even at a high dose of 50 mg/kg. The memory deficit induced by diphenhydramine (10 mg/kg) or pyrilamine (50 mg/kg) was reversed by tacrine (1 mg/kg). CONCLUSION: Histamine H(1)-receptors plays a certain role in spatial cognition, and its action may be due to both histaminergic and cholinergic neurons.

Animals↗

PubMed2001

Cloning a novel mouse Gabarapl2 cDNA and its characterization.

AIM: To clone a novel mouse GABAA-receptor-associated protein like 2 (Gabarapl2) gene, and to analysis its primary function. METHODS: With the aid of computer, the human GABARAPL2 cDNA was used as information probe to search mouse EST database of GenBank for mouse homolog. A series of overlapping EST were found and assembled into an EST contig using Genetics Computer Group (GCG) ASSEMBLY program. The existence of the gene was then identified by experiment. Northern blotting was performed to hybridize [alpha-32P]dATP labeled probe with mRNA of 11 different mouse tissues that had been transferred to the nylon membrane. RESULTS: The novel gene was deposited in GenBank under Accession No AF190644. Its cDNA contained an intact open reading frame and a canonical polyadenylation signal AATAAA followed by polyA. The deduced protein was completely identical to that of human GABARAPL2, and was termed Gabarapl2 by Mouse Gene Nomenclature Committee. The putative protein of Gabarapl2 has a calculated molecular weight of 13 700 and an isoelectric point of 8.56. It was also predicted to contain two protein kinase C phosphorylation sites and one tyrosine kinase phosphorylation site. Northern hybridization showed that Gabarapl2 was expressed as a single 1.35 kb transcript, with high levels in brain, thymus, lung, heart, kidney, and liver, and low in pancreas, testis, small intestine, colon, and stomach. CONCLUSION: A novel mouse Gabarapl2 gene was cloned and identified.

Adaptor Proteins, Signal Transducing↗

PubMed2001

[Detection of proteins and mRNA of p16, p53 and nm23 in mucoepidermoid carcinoma of salivary glands and their prognostic significance].

OBJECTIVE: To disclose the relationship between the expression of p16, p53 and nm23 and the significant morphologic characteristics in mucoepidermoid carcinoma. METHODS: The proteins and mRNA in paraffin blocks from 41 mucoepidermoid carcinoma patients were studied with immunohistochemical methods and in situ hybridization respectively. RESULTS: The negative expression of p16 was found in 62.5% (15/24) of the low differentiation grade and in 29.4% (5/17) of the high differentiation grade (P = 0.037). The positive p53 expression was detected in 70.8% (17/24) of the low grade neoplasms and in 23.5% (4/17) of the high grade (P = 0.003), while positive nm23 protein was present in 37.5% (9/24) and 64.7% (11/17) respectively (P = 0.086). However, no relationship was found between positive mRNA of p16, p53, nm23 and WHO pathologic grade. CONCLUSIONS: There is a significant correlation between expression of p16 and p53 and WHO pathologic grade of mucoepidermoid carcinoma, which indicates clinical prognostic significance. No correlation is noticed between the pathologic grade and the expression of nm23 protein and mRNAs of p16, p53 and nm23.

Adult↗

PubMed2001

[Effect of grazing rate on biomass and element composition of Xanthoparmelia camtschadalis].

Xanthoparmelia camtschadalis is widely distributed in grassland area of Mongolian Plateau. There are few studies on the relationships between biomass, element composition and stocking rate. The relationships of biomass and element composition of Xanthoparmelia camtschadalis to grazing rates in Leymus chinensis steppe in Inner Mongolia were investigated. The results indicated that the biomass of the lichen was highest under light grazing, while the lowest under extremely overgrazing treatment. The C, N and Ca concentrations were higher than 1%, P, Mg, K and Fe were between 0.1% and 1%, and Na, Mn, Cu, Zn, and B were less than 0.1%. The Ca content in Xanthoparmelia camtschadalis was much higher than that in vascular plant. With an increasing grazing rate, the C concentration decreased, while N increased. The C/N ratio was the lowest under moderate and heavy grazing treatments. Ca, Mg, K, Fe, Mn and Cu contents were higher under grazing treatments. The changes of biomass and element composition of Xanthoparmelia camtschadalis had a good response to grazing rate, and hence, it was a good indicator to indicate the healthy condition and changes of biogeochemistry cycles in grassland ecosystems.

Animals↗

PubMed2001

[A method of desulfurization with calcium sulfite and it's mechanism].

Directing to the scaling problem lying in wet desulfurization with lime slurry, a method of desulfurization with calcium sulfite was proposed. Reaction mechanism and the effects of different conditions on desulfurization efficiency were studied. The optimum conditions were obtained, i.e. air velocity of 2.75 m/s in empty tower, L/G = 3.0 L/m3, solid content 6.7%, air temperature 31 degrees C, concentration inlet of SO2 1500 x 10(-6) and inlet suspension pH of 8.0. Under the conditions, the desulfurization efficiency was about 87%. The presented method theoretically and practically solved the scaling problems, which is a novel indirect lime-method with Ca-contained material as desulfurization agent.

Calcium↗

PubMed2001

[Experiment observations of the germicidal effects of disinfectants on Vibro cholerae of El Tor biotype in different water bodies].

OBJECTIVE: To study the germicidal effect of disinfectant on vibro cholerae of El Tor biotype in different water bodies and to set a guidelines for disinfection in the epidemic foci of cholera. METHODS: The suspension quantitative bactericidal test was used to examine the germicidal effects of four kinds of disinfectants, including Chlorine compound disinfectant, Indophor, Chlorine dioxide and Glutarldehyde, on vibro cholerae of El Tor biotype in waste water from residential areas and hospitals, and water from ditches, rivers and seas. RESULTS: When germicidal rate for Vibrio Cholerae of El-Tor biotype in the five different kinds of water bodies reached to 100% in five minutes, concentrations of Chlorine compound disinfectant, Indophor, Chlorine dioxide and Glutaraldehyde were 25.0-250.0 mg/L, 100.0-250.0 mg/L, 10.0-25.0 mg/L and 100-500 mg/L, respectively. CONCLUSIONS: Germicidal effects of the four kinds of disinfectants on Vibrio Cholerae of El-Tor biotype differed, and so did germicidal effect of each of the same disinfectant on it in the five different kinds of water bodies. Concentrations of disinfectants needed to disinfected waste water was higher than that to disinfect natural water.

Chlorine Compounds↗

PubMed2001

[A study of Humphrey three zone screening to detect visual field of the patients with pituitary macroadenomas].

OBJECTIVE: To evaluate the clinical application of Humphrey three zone screening in detecting the visual field of the patients with pituitary macroadenomas (PMA). METHODS: There were two groups in the study. The PMA group: 128 PMA cases were selected who had symptoms of visual problem and been diagnosed with computer tomography (CT) or magnetic resonance (MR) and without apparent opacity of refractive medium. The low myopia group: thirty cases with low myopia and without other eye diseases were included. Humphrey three zone screening method was used to detect the 76-points in the central 30 degree visual fields of the patients of the two groups. RESULTS: In PMA group, 99.2% of the 128 patients and 87.1% of their eyes had visual field defect. 86.7% of the patients had the visual field defect mainly located at the temporal side and showed or tended to have a medial vertical limit. In detecting abnormality of the patients, three zone screening test had a sensitivity of 99.2% (percent of cases with true visual field defect identified by the field test). The mean test duration of each eye is (5.8 +/- 2.2) minutes. In low myopia group, two eyes of two patients had visual field defect. In testing the normal group, three zone screening test had a specificity of 93.3% (percent of cases without true visual field defect appropriately identified by the field test). CONCLUSION: Humphrey three zone screening has very high sensitivity and specificity in detecting visual field, and it is simple, fast and practical for detecting the visual field of the patients with PMA. It plays an important role in implying diagnosis and avoiding misdiagnosis of PMA.

Adenoma↗

PubMed2001

A bicistronic retroviral vector to introduce drug resistance genes into human umbilical cord blood CD34+ cells to improve combination chemotherapy tolerance.

OBJECTIVE: To study whether human umbilical cord blood CD34+ cells transduced with human aldehyde dehydrogenase class-1 (ALDH-1) and multidrug resistance gene (MDR1) have increases resistance to 4-Hydroperoxycyclo-phosphamide (4-HC) and P-glycoprotein effluxed drugs. METHODS: A bicistronic retroviral vector G1Na-ALDH1-IRES-MDR1 was constructed and used to transfect the packaging cell lines GP + E86 and PA317 by LipofectAMINE method, using the medium containing VCR and 4-HC agents for cloning selection and ping-ponging supernatant infection between the ecotropic producer clone and the amphotropic producer clone, we obtained high titer amphotropic PA317 producing cells with high titers up to 5.6 x 10(5) CFU/ml. Cord blood CD34+ cells were transfected repeatedly with supernatant of retrovirus containing human ALDH-1 and MDR1cDNA under the stimulation of hemopoietic growth factors. RESULTS: Bicistronic retroviral vector construction was verified by restriction endonuclease analysis. Polymerase chain reaction (PCR), reverse transcription (RT)-PCR, Southern blot, Northern blot, fluorescenceactivated cell sorting (FACS) method and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) analyses showed that dual drug resistance genes have been integrated into the genomic DNA of cord blood CD34+ cells and expressed efficiently. The transgenes recipient cells confered 4-fold stronger resistance to 4-HC and 5.5 to 7.2-fold P-glycoprotein effluxed drug than untransduced cells. CONCLUSION: The bicistronic retroviral vector-mediated transfer of two different types of drug resistance genes into human cord blood CD34+ cells and co-expression provided an experimental foundation for improving combination chemotherapy tolerance in tumor clinical trial.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

Analysis of hypermutation of the 5' noncoding region in the BCL-6 gene.

OBJECTIVE: To investigate BCL-6 gene mutations in Chinese populations with B-cell non-Hodgkin's lymphoma. METHODS: Polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE) and direct DNA sequencing were used to identify mutations in the 5' noncoding region of the BCL-6 gene in a total of 40 cases of diffuse large-cell lymphoma (DLCL) and follicular lymphoma (FL). RESULTS: Nine cases were found to have base substitutions. The incidence of BCL-6 gene mutation and the frequency of single-base changes were approximately 25.7% and (0.56-1.10) x 10(-2)/bp, respectively. CONCLUSIONS: The 5' regulatory region of the BCL-6 gene undergoes frequent somatic hypermutation during lymphomagenesis and the identification of BCL-6 gene hypermutations provides a molecular marker for confirmatory diagnosis of B-NHL.

5' Flanking Region↗

PubMed2001

Identification and function of glucose transporter 1 in human mesangial cells.

OBJECTIVE: To evaluate the role of glucose transporter 1 (GLUT1) in the glucose uptake of glomerular mesangial cells. METHODS: Cultured human glomerular mesangial cells were used. The expressions of glucose transporter 1 mRNA and protein were detected with reverse transcription-polymerase chain reaction (RT-PCR), flow cytometry and immunofluorescence staining. Glucose uptake was determined with 2-deoxy-[3H]-D-glucose uptake assay. RESULTS: The expressions of GLUT1 mRNA and proteins were detected in human mesangial cells. Glucose uptake and its kinetics assay showed that GLUT1 is a functional glucose transporter in cultured human mesangial cells, and that its function could be inhibited by the specific inhibitor, Phloretin. CONCLUSION: GLUT1 is the predominant glucose transporter in human mesangial cells, which has the kinetic characteristics of high affinity and low capacity for D-glucose. This suggests that in order for mesangial cells to take up excessive quantities of glucose, as in diabetes, changes in glucose transporter expression, translocation or activity may be required.

Glomerular Mesangium↗

PubMed2001

Confirmation of susceptibility gene loci on chromosome 1 in northern China Han families with type 2 diabetes.

OBJECTIVE: To confirm previous effort to identify type 2 diabetes susceptibility genes in a Northern Chinese population by conducting a new genome scan with both an increased number of type 2 diabetes families and a new set of microsatellite markers within the previously localized regions. METHODS: A genome scan method was applied. After multiplexed PCR, electrophoreses, genescan and genotyping analysis, we obtained size information for all loci, and then a further study was done by both parametric and non-parametric linkage analysis to investigate the P values and Z values of these loci. RESULTS: We surveyed 34 microsatellite markers which distributed within 5 regions along chromosome 1, and a total of 12,000 genotypes were screened. Evidence of linkage with diabetes was identified for 8 of the 34 loci. All P values of the 8 loci were lower than 0.05, and the highest Z value was 2.17. A very interesting finding is that all 5 markers at the p- terminal 1p36.3-1p36.23 region, spanning a long range of 16.9 cM, were identified to have a low P value of less than 0.05, which suggests that this region may contain multiple susceptibility genes. Regions 4 and 5 also confirmed the previous findings, and we narrowed these two regions to a 2.7 cM and 2.5 cM regions, respectively. CONCLUSIONS: We further confirmed the results gained in the previous genome-wide scan using an increased number of NIDDM families and a new set of microsatellite markers lying within the initially localized regions. The fact that all 5 loci at the p- terminal region displayed a low P value of less than 0.05 suggests that more than 1 susceptibility gene may reside in this region.

Chromosomes, Human, Pair 1↗

PubMed2001

Treatment of hepatic failure with artificial liver support system.

OBJECTIVE: To assess the effectiveness of artificial liver support system (ALSS) treatment in patients with hepatic failure. METHODS: 235 cases of hepatic failure were treated with ALSS in our hospital. All data were analyzed by SPSS. The effectiveness of ALSS treatment was compared according to different stages (i.e., early, middle and end stages). RESULTS: 108 patients survived after therapy of ALSS. After each ALSS treatment, the liver function of these patients was greatly improved, the serum endotoxin and HBV-DNA concentrations were significantly decreased, and the serum concentration of aromatic amino acids (AAA) such as methionine decreased while the ratio of branched chain amino acids and aromatic amino acids (BCAA/AAA ratio) increased; patients treated with ALSS in the early or middle stages of disease had much higher survival rates than patients in the end stage of disease. CONCLUSION: ALSS is a reliable therapy for advanced liver diseases and treatment at early or middle stages is appropriate.

Adult↗