Biomedical subjects

W Chen

Publications and source records attributed to W Chen.

At least 505 records · Page 28Linked to original sources

PubMed1999

[Expression and distribution of bFGF mRNA in lung tissue of rat with chronic pulmonary hypertension].

To evaluate the role of basic fibroblast growth factor (bFGF) in the development of hypoxic pulmonary hypertension, 30 wistarmale rats were divided into hypoxic group and control group. Rat models with chronic hypoxia induced pulmonary hypertension were established. The pulmonary hemodynamics was measured and the concentration of bFGF in rat lung tissue was determined quantitatively by enzyme-linked immunosorbent assay (ELISA). Expression and distribution of bFGF messenger ribonucleic acid (mRNA) in rat lung was observed by in situ hybridization using digoxigenin-labeled oligonucleotide probe. The result showed the mean pulmonary artery pressure and the concentration of bFGF in rat lung tissue were 3.96 +/- 0.47 kPa, 18.06 +/- 2.97 pg/ml in rats exposed to hypoxia for 3 weeks, respectively; both were significantly higher than those in control group (P < 0.01, P < 0.001 respectively); expression of bFGF mRNA in the wall of pulmonary arterioles in rats exposed to hypoxia was stronger than that of control group. bFGF mRNA increased obviously in endothial cells, smooth muscle and advential tissue of pulmonary arterioles. These suggest that bFGF takes part in reconstruction of pulmonary arterioles wall in chronic hypoxic pulmonary hypertension, and the main mechanism of bFGF in modulating the structural remodeling of pulmonary arterioles may be autocrine and paracrine.

Animals↗

PubMed1999

[The change of plasma level of endothelin-1 in patients with cor pulmonale and the effects of Captopril].

The purpose of this study was to investigate the role of endothelin(ET) in the development of cor pulmonale and the mechanism of captopril in treatment. The plasma ET-1 levels of 36 patients with cor pulmonale and 20 normal subjects were measured by radioimmunoassay. Twenty patients were treated with antibiotics and oxygen, and the other 16 patients were treated with antibiotics, oxygen and captopril for 14 days. The results showed that the ET-1 level of patients with cor pulmonale (88.9 +/- 8.9 ng/L) was significantly higher than that of normal control (53.5 +/- 5.1 ng/L). After treatment, the ET-1 level declined significantly in both groups of patients (P < 0.01); the ET-1 level in patients treated with captopril was lower than that in patients not treated with captopril (P < 0.05), but the level of ET-1 in patients was still higher than that of normal control (P < 0.05). These suggest that ET-1 may play an important role in the onset of cor pulmonale and captopril can reduce the ET-1 level.

Adult↗

PubMed1999

[The effects of combined use of multiple growth factors on proliferation and differentiation of human osteoblast-like cells].

Four growth factors PDGF, bFGF, IGF-II and TGF-beta, which is believed to have biological effects on bone cells, were examined in this study. The aim was to assess the effects of combinations of three and four growth factors on the proliferation and differentiation of osteoblast-like cells. The incorporation of 3H-TdR, 3H-Proline of osteoblast-like cells and alkaline phosphatase content of the cells were tested. The results showed the combinations of three and four growth factors stimulated the synthesis of DNA, collagen and ALP of osteoblast-like cells. These four growth factors interacted synergistically. The combinations of three and four growth factors showed stronger promoting effect on osteoblast-like cells, compared with the combinations of two growth factors. These findings suggest that the combined use of growth factors be a potential way of bone defect reconstruction and treatment of human bone disease.

Cell Differentiation↗

PubMed1999

[The diagnostic and therapeutic value of flexible bronchoscopy in foreign-body aspiration misdiagnosed as other respiratory diseases].

To explore the causes of missed diagnosis of foreign-body aspiration and summarize the experiences on the diagnostic and therapeutic use of flexible bronchoscopy (FB) in these patients. Twelve cases of foreign-body aspiration misdiagnosed as other respiratory diseases, confirmed by FB examination were analyzed. All of these patients had no histories of foreign-body aspiration, and no foreign-body shadows were found on their chest films. But there were atelectasis, hilar enlargement and obstructive pneumonia found on the films. Among the patients in this group, 7 cases were misdiagnosed as lung cancer, 2 cases of pneumonia and asthma each, and 1 case as tuberculosis. The diagnoses of all the 12 cases were confirmed by FB examinations. The foreign-bodies of the 11 cases were successfully grasped and taken out through the FB. This suggests that FB should be of great diagnostic and therapeutic value in patients with foreign-body aspiration misdiagnosed as other respiratory diseases.

Adolescent↗

PubMed1999

[Effects of two growth factors combination on the proliferation and differentiation of human osteoblast-like cells].

OBJECTIVE: To examine the effects of platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF-II) and type beta transforming growth factor(TGF-beta) which were believed to have biological effects on bone cells on human osteoblast-like cells. METHODS: 3H-TdR, 3H-Proline and alkaline phosphatase of the osteoblast-like cells were tested to study the combinating effects of different growth factors on the proliferation and differentiation of osteoblast-like cells. RESULTS: The combination of different growth factors had promotive effect and synergic interact on proliferation and differentiation of osteoblast-like cells. CONCLUSION: The phenomena indicate that the combination of two growth factors will enhance the biological effects of bone formation.

Cell Differentiation↗

PubMed1999

[Ciliary neurotrophic factor in the regeneration of facial nerve].

OBJECTIVE: To study the role of CNTF in regeneration of facial nerve. METHOD: SD Rat facial nerves in temporal bones were transected and then combined end to end. In ciliary neurotrophic factor group (n = 30), lesions were covered by gelatin sponge soaked with CNTF. In control group (n = 18), lesions were covered by gelatin sponge soaked with normal saline. 2, 4, 12 weeks after the operation, both CNTF group and SAL group undergone electrophysiology test and histopathology as well as quantity analysis. RESULT: Two weeks later, both CNTF and SAL group failed in eliciting muscular excitement by stimulating facial nerve; T-test showed significant difference between the two groups(P < 0.05) about the average of myelinated axons 4 weeks later, the latency of facial muscular excitement was 7.650 +/- 2.702 ms in CNTF group and 16.080 +/- 0.162 ms in SAL group. The average number of myelinated axons was 1614 +/- 411 in experimental group and 1094 +/- 343 in control group. T-test showed significant difference between them (P < 0.05). 12 weeks later, latency of facial muscle excitement was 2.016 +/- 0.122 ms in CNTF group and 2.060 +/- 0.162 ms in SAL group. The average number of myelinated axons was 1909 +/- 332 in experimental group and 1847 +/- 422 in control group. T-test showed no significant difference between the two groups (P > 0.05). CONCLUSION: CNTF enhance facial nerve regeneration in adult SD rats.

Administration, Topical↗

PubMed1999

[Determination of bentazon and 2,4-D butyl in mixture formulation by HPLC].

Bentazon and 2,4-D butyl(the active ingredients of Cao Di) were determined by reversed phase HPLC aimultancously using methanol/acetonitrile/citrate buffer(pH 3.1) as a mobile phase on Shim-pack clc-CN column. Results showed that the linear correlation and recovery of 2,4-D butyl were 1.000 and (100.2 +/- 0.8)% respectively, and those of bentazon were 1.000 and (98.6 +/- 0.9)% respectively. The coefficients of variation for bentazon and 2,4-D butyl were all was 0.37%.

2,4-Dichlorophenoxyacetic Acid↗

PubMed1999

[A measurement and analysis on the dynamic changes of wall shear stress in altered arterial flow].

This study was designed to estimate the dynamic changes of wall shear stress in reduced arterial flow and hence to get a better understanding of its effect on the endothelial adaptive remodeling. Left common carotid arteries of experimental rabbits were ligated distal to the origin of the thyroid artery to reduce flow by about 90% in the carotid upstream of this branch, and the vessels were examined respectively at different time intervals. The changes of mean shear stress showed three different stages. The shear stress decreased significantly during postoperative 1 hour to 7 days, increased markedly after 7 days and returned to control levels after 30 days. These changes were closely related to the decreased arterial diameters. The results indicate that the shear stress may paly an important role in the arterial remodeling after alterations in blood flow.

Adaptation, Physiological↗

PubMed1999

[Studies on DNA-DNA hybridization and 16S rDNA sequence of rhizobia isolated from Shapotou desert soil in Ningxia autonomous region of China].

Based on the previous studies on numerical taxonomy and multilocus enzymes electrophoresis patterns of the 12 rhizobial strains isolated from Shapotou region, the contents of G + C mol%, DNA-DNA relatedness and 16SrDNA sequence of the representative strain were tested. The DNA G + C content of the members of this group ranged from 56.4 to 62.2. The values of DNA-DNA hybridization within the group were above 70%, and relatendness between representative strains of this group and known rhizobial species was below 66.6%. The full-length of 16S rDNA sequence of representative strain N220 was compared with the type strains of all known rhizobia species and related bacteria by the PHLIP version 3.572c composed a unrooted phylogenetic tree, the strain N220, R. galegea, two unnamed rhizobial strains(SH19312, SH22623) and three A-grobacterium strains constituted a branch in this tree. The similarity values of 16S rDNA sequence between strain N220 and other strains in this branch were above 95%.

Base Sequence↗

PubMed1999

[A study on taxonomy of rhizobia isolated from Kummerwia sp. and Indigofera sp].

The rhizobial strains isolated from Kummerowia and Indigofera and the known reference strains were classified by performing numerical taxonomy. New isolated strains were divided into two new clusters at 83% similarity level. Based on the numerical taxonomy, additional isolates in each cluster were studied by using SDS-PAGE of whole-cell protein. Twenty-four strains isolated from Kummerowia fell into cluster 1. Twenty strains isolated from Indigofera fell into cluster 2. The results of G + C mol% and DNA homology analysis showed that the DNA homologies between the central strain SH713 and SHL042 and the 13 type strains were less than 61%. Thus, the rhizobial strains from Kummerowia and Indigofera were two new individual species of Rhizobium.

Bacterial Proteins↗

PubMed1999

[Distinction of yeast flocculent phenotypes and studies of the physiological and biochemical characteristics of yeast flocculation].

More than 400 yeast strains were examined for their flocculation, and five of them displayed strong flocculation. The 5 strains were divided into two groups which are Flo 1 and NewFlo phenotypes on the basis of their response to sugar inhibition. Related physiological and biochemical characteristics of the two phenotypes' strains were studied. The results showed that the flocculation of Flo 1 phenotype was only inhibited by mannose; it was sensitive to high temperature (70 degrees C), pronase E, trypsin, whereas tolerant to pronase K, chymotrypsin, Ca2+, pH; the flocculation of NewFlo was inhibited by many sugars, such as glucose, maltose, sucrose, mannose; it was sensitive to high temperature (70 degrees C), pronase, Ca2+, pH. The Calcium concentration and pH value of the optimum flocculaton of the Flo1 and NewFlo phenotypes strains were respectively 10 mmol/L-1 mol/L; 3.0-4.5.

Culture Media↗

PubMed1999

[Study on polyphasic taxonomy of rhizobia isolated from Lespedeza species].

The diversity of rhizobia isolated from Lespedeza spp. was determined on the basis of numerical analysis of phenotypic characteristics, sodium dodecyl sulfate-polyacrylarmide gel electrophoresis (SDS-PAGE) of proteins, DNA-DNA homology and restriction fragment length polymorphism (RFLP) analysis of 16S-ribosomal DNA genes. According to numerical analysis of 125 phenotypic characteristics, strains were divided into two groups at a similarity level of 67%. Group I included all the fast-growing strains, group II included all the slow-growing strains. Above the similarity level of 80%, four subgroups could be further divided. Subgroup I was fast-growing rhizobia containing representative strain of Sinorhizobium saheli. Subgroup II, III, IV were slow-growing rhizobia. Subgroup II composed of strains isolated from Lespedeza cuneata in Beijing area and these isolates produced acid in medium containing mannitol. Subgroup III included type strain of Bradyrhizobium japonicum. The DNA G + C contents and DNA-DNA homology of the members of above four subgroups were determined. The subgroup I shared the same DNA homologous group with S. saheli, subgroup III belonged to B. japonicum, subgroup IV belonged to B. elkanii, subgroup II was an unique DNA homologous group which showed low level of DNA relatedness with other slow-growing rhizobia species. RFLP analysis of 16S rDNA genes verified that the subgroup II was a distinctive genealine and showed genetic variation within the strains in it.

Bacterial Proteins↗

PubMed1999

[Purification and partial characterization of antagonistic proteins from Bacillus subtilis B034].

Bacillus subtilis B034, an antagonistic bacteria isolated from the phyllosphere of rice, strongly inhibits the growth of Xanthomonas oryzae pv. oryzae which causes the rice bacterial blight. Crude extract was obtained by precipitation of the cell-free culture of B034 with 70% saturated (NH4)2SO4. The suspension of the precipitate strongly inhibits Xanthomonas oryzae pv. o-ryzae, and it is thermostable, resistant to trypsin, partial sensitive to proteinase K, pronase E and chloroform. Its active pH range is wide, from 4.0 to more than 12.0, relative more stable in high pH. Two antagonistic peaks were obtained from the crude extract of B034 after Phenyl-Sepharose CL-4B, DEAE-Sephacel and FPLC Superdex 75 HR 10/30 column chromatography. One of these two peaks, named P2, was showed only single band with 50.3 kD and pI6.25 in SDS-PAGE and PAGE-IEF, respectively. The N-terminal partial sequence of protein P2 was analyzed.

Amino Acid Sequence↗

PubMed1999

[A pilot study on malaria control by using a new strategy of combining strengthening infection source treatment and health education in mountainous areas of Hainan province].

AIM: To explore a new malaria control strategy that fits current epiodemiological condition and coincides with modern medicine model and the principle of cost-benefit. METHODS: The new strategy highlights the risk villages and risk population as the focal point and integrates health education with behavioral intervention. The main anti-malaria measures consists of carrying out health education in risk villages, giving mass drug administrations in risk population staying overnight in the mountain, following up malaria cases for implementing radical cure, but without using traditional residual spraying or impregnating bednets with insecticides. RESULTS: After having adopted the new strategy and taken the control measures, the people's knowledge about malaria increased to a higher level and the indices of malaria reduced to a lower level. The rate of bednet-using in the population was increased from 26.8% to 72.6%. The annual parasite incidence (API) of malaria was declined from 3.5% in 1994 to 1.1% in 1996 and 0.8% in 1997, and the API of falciparum malaria was declined from 1.0% to 0.3% and 0.3% respectively in the townships at the same time. The parasite rate(PR) of malaria was declined from 7.2% in May, 1995 to 2.1% in November, 1996 and 1.2% in October, 1997 and the PR of falciparum malaria was declined from 1.2% in May, 1995 to 0.1% in October, 1997. The proportion of villages without malaria cases was increased from 18.6% in 1994 to 54.2% in 1997, and the number of risk villages with a malaria incidence above 5% was reduced from 14 to 2 at the same time. The ratio of cost/benefit was 1:2.4 in 1995-1996 and 1:4.4 in 1997, showing a better economic benefit. CONCLUSION: The expectant result has been obtained, thereby providing new experience for the malaria control in the mountainous areas of Hainan Province.

China↗

PubMed1999

[Diagnosis and restitution of nasal bone fracture].

OBJECTIVE: To discuss accurate methods of diagnosis and restitution for nasal bone fracture. METHOD: 280 cases of nasal trauma were examined by lateral x-ray test (horizontal CT-scan was also used in 76 cases of these patients). RESULT: 220 cases were found with bilateral fracture of nasal bone. Unilateral fracture, simple fracture of frontal process of maxilla, compound fracture of nasal bone and frontal process of maxilla, compound fracture of nasal bone, maxilla and perpendicular plate of ethmoid bone were seen in 12, 15, 30 and 3 cases respectively. CONCLUSION: X-ray examination can only find bilateral fracture of nasal bone, but CT-scan can demonstrate unilateral fracture, fracture of frontal process of maxilla and fracture of perpendicular plate of ethmoid bone. Restitution with pincers is still a routine therapeutic method for nasal bone fracture at present, and nasal septal reconstruction is necessary when both nasal bone and perpendicular plate of ethmoid bone were involved. But for those patients with high-position compound fracture, restitution by directly visual operation through lip-dental-gum approach is the best choice.

Adolescent↗

PubMed1999

[Middle ear operation of children and juveniles].

OBJECTIVE: To analyse the results and effective factors of middle ear operation in children and juveniles. METHOD: 105 cases (146 ears) were analyzed retrospectively. 49 ears were followed up over 3 months. RESULT: 120 ear had perfect hearing materials. The difference of average air-bone gap between postoperation (21.86 +/- 13.15) dB HL and preoperation (35.20 +/- 13.87) dB HL was significant (P < 0.01). CONCLUSION: Middle ear operation was a safe, effective operation in children and juveniles, reoperation also was proper option for someone if his first operation didn't success or repeated cases.

Adolescent↗

PubMed1999

[Effects of the water-soluble extracts from the single herb of ganduqing against hepatitis B virus in vitro].

Comparing with Ara-Amp, the effects of the water-soluble extracts from the single herb of the formula for Ganduqing on HBeAg and HBsAg expression in 2.2.15 cells were studied. The results showed that the extracts of Serissa serissoides (DC) Druce, Hibiseus mutabilis Linn, Paedeuia scangens (Lour) Merr var tomentosa (BL) Hand-Mazz, Plumbago zeylanica L, Garcinia oblougifolia Champ and Begpnia edulia Levl had marked inhibition effects on HBeAg and HBsAg which expressed by 2.2.15 cells.

Antiviral Agents↗

PubMed1999

[Studies on chemical constituents of the stem bark of Taxus cuspidata].

In order to study the active constituents in the stem barks of Taxus cuspidata Sieb. et Zucc., led to the isolation and structural determination of three compounds. On the basis of chemical evidences and spectral analysis (UV, IR, 1HNMR, 13CNMR and FAB-MS,) the structures of I, II and III were elucidated as baccatin I 1-hydroxy, taxinine J 2-deacetoxy and beta-sitosterol. Compound I was found from this plant for the first time.

Alkaloids↗