Biomedical subjects

G Zhang

Publications and source records attributed to G Zhang.

At least 163 records · Page 9Linked to original sources

PubMed2001

[Appraisement of the operative therapeutical effects of salpingocatheterism for refractory otitis media].

OBJECTIVE: The therapeutical effects of salpingocatheterism and the states of tubal function were studied after different middle ear operations and within different middle ear pathological changes. METHOD: Total 71 patients with tubal occlusion, 18 of myringoplasty, 20 of reconstruction of ossicolar chain followed tympanoplasty, 14 of combined approach tympanoplasty, 10 of radical mastoidectomy followed tympanoplasty, 9 of re-radical mastoidectomy followed tympanoplasty were implemented salpingocatheterism. The patients were followed up for evaluation of the postoperative therapeutical effects and the state of tubal function. RESULT: The causes of operation failure in different middle ear operations or different middle ear pathological changes had no significantly difference. The major cause for postoperative tympanic membrane perforation and tubal occlusion was the pathogenic damage being not cleared up thoroughly and/or there being nasal cavity or pharyngeal cavity pathogenic changes accompanied. CONCLUSION: Salpingocatheterism is effective for preventing eustachian tube postoperative adhesion.

Adolescent↗

PubMed2001

[Revision endoscopic sinus surgery on chronic sinusitis and polyps].

OBJECTIVE: To study the indications, surgical landmarks, surgical significance, complications and operative avoidance of revision endoscopic sinus surgery on chronic sinusitis and polyps. METHOD: We performed revision endoscopic sinus surgery on 112 cases of chronic sinusitis and polyps under controlled hypotension anaesthesia by using the Messerklinger technique and Stryker debrider. RESULT: 89 cases were successful and 17 unresolved, 6 failed, all the complications consist of cerebrospinal fistula in one, orbital hematoma in four, increased tearing in three and profuse bleeding in 6 patients. CONCLUSION: Revision endoscopic sinus surgery was advised in case of sinuous obstruction caused by uncontrolled lesions under postoperative care, which can do good for adhesion and obstruction except nasal polyposis. The remanet of the middle turbinate and the upper arch of choana were helpful operative landmarks. Preoperative CT scan decrease the complications.

Adolescent↗

PubMed2001

[Experimental study of reinforcing effect of bushen yijing capsule on bone quality of cancellous bone in ovariectomy caused rats osteoporosis model].

OBJECTIVE: To explore the influence of Bushen Yijing Capsule (BSYJC) on bone quality of cancellous bone in ovariectomize induced osteoporosis rats model. METHODS: Forty Wistar female rats, 10 months old, were randomly divided into 4 groups, the normal group, the model control group, the premarin treated and the BSYJC treated group, 10 in each group. The normal group was only sham operated and the other three were ovariectomy performed and treated starting at day 91 postoperationally for consecutively 90 days. Rats were sacrificed at the end of experiment, the second lumbar vertebra was taken out to determine bone density and contents of calcium, phosphorus and organic substances, and the third lumbar vertebra taken out to measure the bone density and biomechanics properties. Bone quality was evaluated with the above indices. RESULTS: BSYJC could significantly raise the bone density, increase the contents of calcium, phosphorus and organic substances, and improve the biomechanical properties of the lumbovertebral bone in osteoporosis rats. CONCLUSION: BSYJC could improve the bone quality of the cancellous bone in ovariectomized rats.

Animals↗

PubMed2001

[Study of bone mineral density measuring system with quantitative CT].

This paper introduces a kind of bone mineral density(BMD) measuring system with quantitative CT(QCT). This system includes a self-made solid calibration phantom for BMD and the measuring software. The results of the tests have showed that this system is reliable, cheap and ease of use for BMD measurement.

Absorptiometry, Photon↗

PubMed2001

[Expression of vascular endothelial growth factor and nm23 as prognostic factors in nasopharyngeal carcinoma].

OBJECTIVE: To evaluate the prognostic significance of vascular endothelial growth factor (VEGF) and nm23 expression for patients with nasopharyngeal carcinoma(NPC). METHODS: From Jan. 1991 to Dec. 1995, 75 NPC patients treated in Department of Radiotherapy & Chemotherapy, Zhongnan Hospital of Wuhan University, with follow-up of more than 4 yrs, were selected to enter this study. Specimens of 75 NPC were studied by immunohistochemical staining for VEGF and nm23. The immunohistochemical data were correlated with development of locoregional failure, distant metastasis and survival. RESULTS: Positive expression of VEGF and negative expression of nm23 were found in 54.7% and 56% of NPC specimens. Positive expression of VEGF and negative expression of nm23 correlated with the development of distant metastasis (P = 0.0181; P = 0.0091) and shorter survival (P = 0.0136; P = 0.0207). No association was observed with locoregional failure. No association was observed between the expression of VEGF and the expression of nm23.Cox proportional hazard model was used to compare the various factors and found the VEGF and nm23 expression were significant prognostic factors for patients with NPC. CONCLUSION: The results of the study show that the VEGF and nm23 expression are significant prognostic factors for patients with NPC and indicate that expression of VEGF and nm23 may be useful in identifying patients who may benefit from systemic chemotherapy or other novel treatment strategies.

Adolescent↗

PubMed2001

Expression and glycosylation of rotavirus strain SA11 VP4 protein in a recombinant adenovirus.

OBJECTIVE: Using a recombinant human adenovirus to express modified VP4 gene of rotavirus SA11 strain. METHODS: A whole VP4 gene was obtained with PCR and induced the signal peptide at the gene N terminal. The chimera gene was cloned into pCMV plasmid that consists of human cytomegalovirus promoter, and then the gene was cloned to the transfer vector of human adenovirus type 5. Homologous recombination was performed by co-transfection to 293 cell lines with recombinant plasmid and viral genome using CaPO4 precipitation. RESULTS: No mutation was found in the whole VP4 gene sequence of 2362 base pair. The expressed product in recombinant adenovirus was confirmed to be specific and more antigenicity by indirect immunofluorescence assay. Both the Western blot and immunoprecipitation assay showed that the molecular mass of the expressed protein was higher than the wild type VP4 protein, and that the modified product was corresponding to a glycosylation of VP4 protein. CONCLUSION: To modify the target gene might be an effective method to enhance the stability, antigenicity and immunogenicity of expressed protein.

Adenoviruses, Human↗

PubMed2001

Relationship between human parvovirus B19 infection and aplastic anemia.

OBJECTIVE: To explore the relationship between human parvovirus B19 (HPV B19) infection and aplastic anemia (AA) and to investigate the role of HPV B19 in the occurrence of AA. METHODS: The presence of HPV B19 DNA was detected in the peripheral blood samples of 60 patients with AA (children 38 and adults 22) by nested polymerase chain reaction (PCR) assay, and 30 healthy persons were selected as control. RESULTS: Sixteen (26.7%) of 60 AA cases were HPV B19 DNA positive, while all the samples in the control group were negative for HPV B19 (P = 0.000914). Among the case group, the positive rates of HPV B19 DNA were 21.4% (6/28), 30.0% (3/10), 20.0% (1/5) and 35.3% (6/17) in children acute AA (AAA), children chronic AA (CAA), adults AAA and adults CAA patients respectively, which were significantly higher than that in the control group. Furthermore, there was no remarkable difference between children AA and adults AA in the 16 HPV B19 DNA positive patients; neither was there between AAA and CAA. CONCLUSION: HPV B19 infection is not only correlated with the occurrence of children AAA and CAA, but also with adults AAA and CAA, and might be an important viral cause for AA in humans.

Acute Disease↗

PubMed2001

[IR studies on hydrogen bonding in hard segment domains of segmented polyester polyurethaneurea].

Hydrogen bonding in hard segment domains of segmented polyester polyurethaneurea (PUU) based on 4,4'-diphenylmethane diisocyanate (MDI), ethylene diamine (ED) and polybutylene adipate (PBA) (M.W.1,975 and M.W.1,228) was studied by means of IR spectroscopy. It was found that the double peak absorption of urea C=O groups occurred in the studied PUU with the increase of hard segment content. Two hydrogen bonding models of urea C=O groups in different hard segment sequence lengths of PUU were proposed. Three dimensional hydrogen bonding in hard segment domains can be formed by further bonding of the above planar hydrogen bondings.

Hydrogen Bonding↗

PubMed2001

[IR studies on deuterated polyester polyurethaneurea elastomers].

Segmented polyester polyurethaneurea (PUU) based on 4,4'-disphenylmethane diisocyanate (MDI), ethylene diamine (ED) and polybutylene adipate (PBA) elastomers and their deuterated polymers were studied by means of IR spectroscopy. The results indicated that IR bands of hydrogen bonded N-H vibrations involved in PUU were greatly affected by deuteration. The bands which were sensitive to deuteration were those near 3,332, 3,190, 1,600, 1,539, 1,317, 1,257 and 1,230 cm-1, respectively. In addition, it was also found that PUU samples with different hard segment contents and polyester soft segment molecule weights were similarly affected by deuteration in degree.

Elasticity↗

PubMed2001

[Raman spectra of nacre from shells of main pearl-culturing mollusk in China].

The Raman spectra of nacre and cultured pearl from main pearl-culturing mollusks in China have been studied systematically in this paper. It shows that: 1) the Raman bands caused by organic matrix have not been observed in nacre from shell of pinctada maxima; 2) in nacre from shell of pinctada martensii and hyriopsis cumingii, besides the bands caused by aragonite mineral, two bands resulted from all-trans carotenoid are obviously observed, and the number of C=C double bonds in molecular of this carotenoid is predicted to be 10 based on the position of its Raman bands; 3) a number of complicated bands are observed in nacre from shell of peteria penguin, and we predicted that this bands perhaps are caused by metalloporphyrin compounds; 4) the relative concentrations of carotenoid and metalloporphyrin in nacre are closely associated with the color of nacre. The Raman spectra research on organic matrix in nacre and cultured pearl provides insight into the applications of them in cosmetics and food, as well as in application of pearl bleaching.

Animals↗

PubMed2001

[IR studies on segmented polyester polyurethaneurea elastomers].

The studies segmented polyester polyurethaneurea (PUU) elastomers based on 4,4'-diphenylmethane diisocyanate (MDI), ethylene diamine (ED) and polybutylene adipate(PBA) (M.W.1,975 and M.W.1,228) were studied by means of IR spectrascopy. The major IR bands of PUU were first assigned and the views were proposed for the bands at 1,600, 1,317, 1,520 and 1,230 cm-1 assigned by other authors. The reliable theoretical basis for the assignments of IR bands and the studies of hydrogen bonding in these elastomers has been proposed by use of deuteration and varying temperature. The results indicated that substantial hydrogen bonding mainly occurred in the aggregate region of hard segments, a small amount of hydrogen bonding can be formed at the interface between the soft and hard segments. It can be concluded from this work that the studied PUU materials were phase segregation.

Elastomers↗

PubMed2001

[The comparisons of fluorescence quenching between perylene and pyrene].

The fluorescence quenching of perylene and pyrene by dimethyl terephthalate (DMTP) and N,N-dimethylaniline (DMA) have been investigated. The results show that pyrene can form exciplex with DMTP or DMA at room temperature and perylene can only form exciplex with DMA. The fluorescence quenching date is in conformity with the Stern-Volmer equation: F0/F = 1 + KSV[Q] = 1 + Kq.tau 0[Q], the F0/F-[Q] straight lines are drawn. The Stren-Volmer constants and fluorescence quenching rate constants (KSV and Kq) are obtained. The Stern-Volmer quenching constants of pyrene is larger than that of perylene. The differences is due to the molecular structure of perylene which is not a typical large conjugated system and less coplanar configuration than pyrene.

Aniline Compounds↗

PubMed2001

[Development and evaluation of continuous-flow apparatus with spectrophotometer for fast reaction].

Microprocessor pump drive continuous-flow apparatus with spectrophotometer for study of fast reaction have been developed. The apparatus consists mainly of a microprocessor pump drive, an UV-240 spectrophotometer, a mix cell and the constant temperature facilities. The performance of this apparatus was evaluated by using the model system of Fe(III)-SCN- reaction. The rate constant values of this reaction system are in agreement with some other experimental results. According to the results of the experimental determination, we can see that this apparatus is easy to be operated and shows high precise in measurement. And the apparatus is suitable for kinetic studies of fast reactions whose half-life is in millisecond order.

Autoanalysis↗

PubMed2001

[The hygienic examination and quality research of Chinese crude drug scorpion].

We selected the method of hygienic test to determinate the infection of colibacilli, salmonelli, mixed bacteria, mould fungus and yeasts on Chinese crude drug scorpion from 29 commerical samples in different storaged period, habitats and commerical standard. The results showed there were not colibacilli and salmonelli in all 29 samples, but infectious mixed bacteria rate is 100%, which is 2.1 times more than salty scorpion in 29 tested samples, and the infectious fungi rate is 72.4%. The fungi of salty scorpion is 15% more than fresh scorpion. The quantity of infected yeasts on salty scorpion is much more than scorpion. There are 4 species of fungi such as Alternaria neesex Wallroth, Aspergillus fumigatus Fresenius, Nocarcia sp. and Tricophyton violaceum Sabouraud. Because of infectious pathogenic bacteria rate is so high, we suggest to increase the item of hygienic test to control the quality of crude drug scorpion and strengthen the administration of commerical drugs, so as to reduce the contaminative condition.

Animals↗

PubMed2000

N-methyl-D-aspartate receptor activation results in regulation of extracellular signal-regulated kinases by protein kinases and phosphatases in glutamate-induced neuronal apototic-like death.

Extracellular signal-regulated kinases (ERK1/ERK2) have been shown transiently activated and involved in excitotoxicity. We searched for upstream molecules responsible for the regulation of glutamate-induced ERK1/ERK2 activation and ERK1/ERK2-mediated apototic-like death in cultured rat cortical neurons. ERK1/ERK2 activation (monitored by anti-active ERK1/ERK2 antibody) was almost completely prevented by blockage of NMDA receptor (NMDA-R) or elimination of extracellular Ca(2+), but not any other glutamate receptor or L-type voltage-gated Ca(2+) channel. It was prevented largely by inhibition of protein kinase C (PKC), protein-tyrosine kinases (PTK), respectively, but mildly by that of CaM kinase II. Combined inhibition of CaM kinase II (but not PTK) and PKC had an additive effect. Reversion of ERK1/ERK2 activation was largely prevented by inhibition of protein phosphatase (PP) 1 or protein tyrosine phosphatase (PTP). Combined inhibition of PP 1 and PTP had no additive effect. Glutamate-induced apoptotic-like death (determined by DAPI staining) was largely prevented by inhibition of NMDA-R, PKC, CaM kinase II, PTK and MEK1/MEK2 (ERK1/ERK2 kinase), respectively. Combined inhibition of CaM kinase II (but not PKC or PTK) and MEK1/MEK2 had an additive effect. Glutamate-induced apoptotic-like death was promoted by inhibition of PP1 and PTP, respectively. The above results suggested that in glutamate-induced cortical neurotoxicity ERK1/ERK2 activation be mainly mediated by NMDA-R. Subsequently, a pathway dependent on both PKC and PTK was mainly involved, which was also mainly responsible for ERK1/ERK2-mediated apoptotic-like death, and a CaM kinase II-dependent pathway was relatively mildly involved. Reversion of ERK1/ERK2 activation was mainly mediated by a pathway dependent on both PP1 and PTP, which might be involved in the restrain of glutamate-induced neurotoxicity.

Animals↗

PubMed2000

Myomegalin is a novel protein of the golgi/centrosome that interacts with a cyclic nucleotide phosphodiesterase.

Subcellular targeting of the components of the cAMP-dependent pathway is thought to be essential for intracellular signaling. Here we have identified a novel protein, named myomegalin, that interacts with the cyclic nucleotide phosphodiesterase PDE4D, thereby targeting it to particulate structures. Myomegalin is a large 2,324-amino acid protein mostly composed of alpha-helical and coiled-coil structures, with domains shared with microtubule-associated proteins, and a leucine zipper identical to that found in the Drosophila centrosomin. Transcripts of 7.5-8 kilobases were present in most tissues, whereas a short mRNA of 2.4 kilobases was detected only in rat testis. A third splicing variant was expressed predominantly in rat heart. Antibodies against the deduced sequence recognized particulate myomegalin proteins of 62 kDa in testis and 230-250 kDa in heart and skeletal muscle. Immunocytochemistry and transfection studies demonstrate colocalization of PDE4D and myomegalin in the Golgi/centrosomal area of cultured cells, and in sarcomeric structures of skeletal muscle. Myomegalin expressed in COS-7 cells coimmunoprecipitated with PDE4D3 and sequestered it to particulate structures. These findings indicate that myomegalin is a novel protein that functions as an anchor to localize components of the cAMP-dependent pathway to the Golgi/centrosomal region of the cell.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2000

Suppression of adhesion and invasion of hepatoma cells in culture by tea compounds through antioxidative activity.

To determine the actions of tea components on the invasion of a rat ascites hepatoma cell line of AH109A and to understand their modes of action, the cancer cells were co-cultured with a rat mesentery-derived mesothelial cell monolayer in the presence of tea components. The synergistic effects of (-)-epicatechin (EC) with (-)-epigallocatechin gallate (EGCG) on AH109A invasion were demonstrated. Further study showed that 10 microM of EGCG or theaflavins, or 2.5 microM of ethylenediaminetetra-acetic (EDTA) entirely abolished the increase in AH109A adhesion and invasion stimulated by reactive oxygen species (ROS) from the hypoxanthine-xanthine oxidase system. Our results suggest that (.)OH(-)- and other ROS-scavenging activity of EGCG and theaflavins may be responsible for the inhibition of (.)OH(-)- and related ROS-potentiated AH109A adhesion and invasion to the cultured rat mesothelial cell monolayer.

Animals↗

PubMed2000

Single amino acid differences are sufficient for CD4(+) T-cell recognition of a heterologous virus by cattle persistently infected with bovine viral diarrhea virus.

Cattle that are persistently infected (PI) with one strain of bovine viral diarrhea virus (BVDV) can resolve infection with a second, antigenically heterologous strain but not the homologous strain. Since CD4(+) T cells are thought to be critical for the resolution of acute BVDV infection (Howard et al., 1992, Vet. Immunol. Immunopathol. 32, 303-314), we have examined the recognition of a heterologous virus (NADL) by CD4(+) T cells from Pe515-PI animals. The immune response of non-PI control cattle challenged with NADL or Pe515ncp was strain cross-reactive, whereas Pe515-PI animals responded to NADL only. The immune repertoire of both groups included NS3, which differs by approximately 1% (9/683) amino acids between these two viruses. Lymphoproliferative responses to proteins and synthetic peptides corresponding to three nonconservative differences in NS3 demonstrated that CD4(+) T cells from non-PI control animals responded well to proteins but poorly to the peptides from both viruses. In contrast, PI animals were responsive to heterologous proteins and peptides but nonresponsive to the homologous equivalents. A single amino acid difference between the two sequences was sufficient to allow responsiveness.

Amino Acid Sequence↗