Biomedical subjects

L Wang

Publications and source records attributed to L Wang.

At least 865 records · Page 48Linked to original sources

PubMed2000

[Study on human sensitivity of extremely low frequency electromagnetic field].

In this paper, the action potential through membrane is calculated and analyzed based on the crowd model. The analysis shows that membrane action potential will be amplified if the coefficient k1, k2 meet some certain conditions. This effect could cause ionic current increase and even results in electroporation, membrane broken. The result can be used to explain some athermal bioeffect of living beings in weak EMF and is helpful for biomedicine application.

Cell Membrane↗

PubMed2000

[Clinical analysis of 40 patients who were re-operated after prosthetic augmentation mammaplasty].

OBJECTIVE: To summarize the reasons of complications after prosthetic augmentation mammaplasty and explore the optimal preventive measures and therapy. METHOD: The reasons for 40 patients who were re-operated on after prosthetic augmentation mammaplasty were analyzed in as many aspects as possible, such as the location of the incision, the type of the prosthesis, etc. Preventive measures and therapy of the complications were also summarized. RESULTS: Capsular contracture was the most common reason for reoperation. The second was prosthetic rupture and translocation. The main reasons resulting in complications included impertinent indications, poor quality of the prosthesis and an incompetent surgeon. CONCLUSIONS: The key to reduce the complications is proper selection of good prosthesis, strict indications, better comprehension of the knowledge about prosthetic augmentation mammaplasty and a qualified plastic and aesthetic surgeon for the operation. The inareolar incision is the best choice to remedy the complications.

Adult↗

PubMed2000

[Effect of electrical lesion of the area postrema on gastrointestinal interdigestive migrating motor complex in conscious dogs].

OBJECTIVE: To investigate the effect of area postrema (AP) of medulla oblongata on gastrointestinal interdigestive migrating motor complex (MMC). METHODS: Interdigestive MMC activity of antrum and duodenum was recorded by strain gauge implanted on the serosa in 8 conscious dogs. Cannula was intubated in the femoral vein for motilin injection. Plasma motilin concentration was measured by RIA. We observed (1) normal interdigestive MMC activity and fluctuation of plasma motilin concentration; (2) the effect of electrically destroying AP on MMC activity and plasma motilin level and (3) whether or not intravenous injection of motilin could induce phase III contractions after AP was destroyed. RESULTS: (1) Typical interdigestive MMC with phases I, II, III and IV was recorded in normal dogs. Phase III was concurrent with the peak of plasma motilin level. (2) In dogs electrically destroyed AP with antroduodenal interdigestive MMC contractions were suppressed; cyclic, phasic and migratory pattern of MMC was disrupted. Plasma motilin concentration was decreased. Intravenous injection of motilin could not induce phase III contractions. CONCLUSION: Area postrema plays an important role, which is mediated by motilin, on the regulation of interdigestive MMC.

Animals↗

PubMed2000

[Effect of hypoxic hypercapnia on expression of endothelin-1 mRNA of pulmonary arterioles in rats].

OBJECTIVE: To investigate the effects of chronic hypoxic hypercapnia and ligustrazine on expression of endothelin-1 (ET-1) mRNA and the ultrastructure of pulmonary arterioles in rats. METHODS: Thirty rats were randomly divided into three groups: control group (A), hypoxic hypercapnic group (B), hypoxic hypercapnia + ligustrazine (lig.) group (C). ET-1 mRNA was observed in arterioles from rats by the technique of in situ hybridization. The average value of integral light density (LD) of ET-1 mRNA in pulmonary arterioles was detected by an image analysor and the relative content of ET-1 mRNA was calculated. RESULTS: (1) mPAP was significantly higher in rats of B group than that of A group (P < 0.01) and it was much lower in rats of C group than that of B group (P < 0.01). Differences of mCAP were not significant in three groups (P > 0.05); plasma ET-1 concentration was significantly higher in rats of B group than that of A group (P < 0.01), plasma ET-1 concentration was significantly lower in rats of C group than that of B group (P < 0.01); (2) Light microscopy showed that WA/TA (vessel wall area/total area) and SMC (the density of medial smooth muscle cells) were significantly higher in rats of B group than those of A group (P < 0.01). WA/TA and SMC were significantly lower in rats of C group than those of B group (P < 0.01). Electron microscopy showed proliferation of medial smooth muscle cells and collageous fibers of pulmonary arterioles in rats of B group, and ligustrazine could reverse the changes mentioned above; (3) Hybridization in situ showed that LD of ET-1 mRNA in pulmonary arterioles was significantly higher in rats of B group than that of A group (P < 0.01); LD of ET-1 mRNA in pulmonary arterioles was significantly lower in rats of C group than that of B group (P < 0.01). CONCLUSIONS: Increase of expression of ET-1 mRNA in pulmonary arterioles contributes to the development of pulmonary hypertension and structural remodeling of pulmonary arteries in chronic hypoxic hypercapnic rats. Ligustrazine can inhibit pulmonary hypertension by decreasing the expression of ET-1 mRNA in pulmonary arterioles.

Animals↗

PubMed2000

[Study on relationship between the apoptosis of hepatocytes and liver fibrosis of chronic viral hepatitis].

OBJECTIVE: To study the relationship between apoptosis of hepatocytes and liver fibrosis of chronic viral hepatitis (CH). METHODS: DNA fragmentation, one of the characteristic features of apoptosis, was detected by in situ terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and the expression of Fas, transforming growth factor beta 1 (TGF-beta 1) and Pre-collagen III peptide (P III P) in liver tissues were detected by immunohistochemistry. Soluble Fas (sFas) and TGF-beta 1 in serum were detected by ELISA. RESULTS: The damage of DNA in hepatocytes of CH correlated closely with the expression of Fas and TGF-beta 1 in liver tissue and serum (r = 0.6129, 0.5368, 0.5564, 0.5996; P <0.05-0.01). In severe type CH and liver cirrhosis, the degree of liver fibrosis and the expression of P III P and TGF-beta 1 were higher than that in mild type and moderate type CH. CONCLUSIONS: The sFas in serum may be one of the factors associated with the apoptosis. The apoptosis of hepatocytes correlated with liver fibrosis of CH and TGF-V beta 1 may play an important role between apoptosis and liver fibrosis.

Adolescent↗

PubMed2000

[The expression of P21 and P15 proteins in liver tissue of chronic viral hepatitis and hepatocellular carcinoma and their relation to cell apoptosis].

OBJECTIVE: To study the expression of P21 and P15 proteins in liver tissue of chronic viral hepatitis (CH) and hepatocellular carcinoma (HCC) and their relation to cell apoptosis. METHODS: The expression of P21 and P15 proteins in 36 CH patients liver tissues were detected by immunohistochemistry and the DNA damage of the hepatocytes were detected by TDT mediated dUDT nick and labeling (TUNEL). 10 cases of HCC were also studied. RESULTS: P21 and P15 proteins mainly distributed in the interstitium of portal areas, the piece meal necrotic sites and the nuclei and cytoplasm of the hepatocytes. The higher expression of P21 and P15 proteins in the interstitium and nuclei of the hepatocytes was seen in CH as compared with that in HCC. The levels of expression of P21 and P15 in moderate and severe type CH were higher with that of the mild type CH (P <0.05). The correlative coefficient of expression of P21 and P15 with the DNA damage of hepatocytes were 0.56, 0.51 respectively (P <0.01). CONCLUSIONS: The enhanced expression of P21 and P15 proteins in CH correlated with the injury of liver tissues and apoptosis of hepatocytes.

Adult↗

PubMed2000

[Landscape heterogeneity of urban vegetation in Guangzhou].

Seven indexes were used to study the landscape heterogeneity of vegetation in Guangzhou City. The results show that the patch density was 11.8 patches.km-2 and the line corridor density was 1.87 km.km-2. In old urban area, the vegetation landscape was characterized by small patches, heavy fragmentation, high diversity and random distribution, showing a highly heterogeneous spatial pattern, while in new urban area, the vegetation landscape was characterized by big patches and even distribution. Therefore, when the size of vegetation area was the same, the even distribution of vegetation could improve the landscape heterogeneity and make the ecological function more effective.

China↗

PubMed2000

[Effects of soil moisture and shading levels on photosynthetic characteristics of cotton leaves].

The effects of different soil moistures and shading levels on stomatal conductance(Gs), net photosynthetic rates(Pn), transpiration and leaf water potential(LWP) of cotton (variety Zhongmian No. 23) grown in pots from the seedling to flower bud stages in summer noon were evaluated. We designed three shading levels: no-shading(CK), 75% shading (DN), 40% shading(SN); and three soil moistures; 85%-100% (high water, HW), 65%-85% (medium water, MW) and 45%-65% (low water, LW) of field water-bolding capacity. The Gs of DN and SN increased by 16.69% and 28.01% compared with CK at HW, respectively, while the Pn of DN and SN declined by 45.74% and 20.54%, respectively. The Gs of DN and SN enhanced by 28.86% and 23.28% compareds with CK at MW, respectively, while the Pn of DN and SN decreased by 31.97% and 1.64%, respectively. The Gs of CK, DN and Sn did not exhibit significant differences at LW, while Pn of DN and SN reduced by 46.22% and 13.45%, respectively. Significant difference in Gs did not exist between DN and SN at the same soil moisture, but there was significant difference in Pa between them (except at LW). It was suggested that Gs declined with the increasing of leaf-to-air vapor pressure difference (VPD) and showed weak correlation with Pn by regression. The combined effects of soil moistures and shading levels on LWP and transpiration rate were not significant. There was no significant difference in LWP and transpiration rate among three shading treatments. Contrasted to treatment CK, intercellular CO2 concentration (Ci) in DN and SN at HW, MW and LW increased significantly, except no apparent change of Ci in SN at MW.

Carbon Dioxide↗

PubMed2000

Effect of IFN-gamma, IL-4 on proliferation and synthesis of hyaluronic acid and collagen in cultured human retroorbital fibroblasts in vitro.

OBJECTIVE: To investigate the cellular immune mechanism of thyroid associated ophthalmopathy (TAO) and provide a basis for treating TAO with cytokine or anti-cytokine agents, we determined whether interferon (IFN)-gamma and interleukin (IL)-4, representative cytokines of Th1 and Th2 cells, may have some effect on the development and progression of TAO. METHOD: Retroorbital fibroblasts (RF) proliferation and the synthesis of hyaluronic acid (HA) and type IV collagen were measured with liquid scintillation and radioimmunoassay. RESULTS: IFN-gamma stimulated RF proliferation and HA synthesis and had a significant inhibitory effect on type IV collagen synthesis. IL-4 stimulated proliferation and type IV collagen synthesis in RF and had inhibitory effect on HA synthesis. When IFN-gamma (100 U/ml) and IL-4 (1 microgram/L) were incubated together with RF, they antagonized their respective stimulatory or inhibitory effect on the proliferation and synthesis of HA and type IV collagen. Thyrotropin (TSH) stimulated RF proliferation and type IV collagen synthesis in a dose-dependent manner, while only at high dose (100 U/L and 200 U/L), stimulated RF to synthesize HA. CONCLUSIONS: IFN-gamma, a representative cytokine of Th1 cells, is responsible for the inflammatory process of TAO; whereas IL-4, a representative cytokine of Th2 cells, has some effect on the repair process. IL-4 could antagonize the inflammatory effect of IFN-gamma on RF. TSH may have aggravating effect on the pathogenesis of TAO.

Adult↗

PubMed2000

[Value of fractional curettage of prehysterectomy in endometrial neoplasms].

OBJECTIVE: To evaluate the value of fractional curettage in the histologic type, histologic grade and cervical involvement of the endometrial carcinoma. METHODS: A total of 691 cases of endometrial carcinoma in fractional curettage specimen were analyzed retrospectively, patients with no carcinoma postoperatively in the removed uterus were excluded from the study. Those endocervical curettages with adenocarcinoma according the histologic relationship between tumor tissue and endocervical tissue were divided into 4 main groups. RESULTS: (1) The inaccurate rate of histologic type in prehysterectomy curettage was 8.83% (61/691). About a half poorly differentiated adenocarcinomas were undergraded in the prehysterectomy curettage. (2) In 691 cases of endometrial carcinomas, 159 (23.01%) cases were determinated cervical involvement by tumor in the hysterectomy specimen, of which 88 cases had tumor tissue in the prehysterectomic curettage. In a variety of histologic appearances of endocervical curettage, the ratio of cervical involvement by tumor in hysterectomy was respectively group I 30.30% (10/33), group II 9 cases (9/9), group III 100.00% (40/40), group IV 46.88% (29/63), those without tumor tissue in the endocervical curettage 12.68% (71/560). CONCLUSIONS: (1) The reliability of histologic type of endometrial carcinoma based on the findings of the fractional curettage specimen in related to the tumor type. The diagnosis of poorly differentiated adenocarcinomas in the prehysterectomy specimen is limited. (2) Determinating the presence or absence of cervical involvement can't only depend upon the endocervical curettage with or without tumor tissue. It is suggested that those endocervical curettage with tumor tissue be divided into 4 main groups according the histologic relationship between tumor tissue and endocervical tissue, group II and group III are good predictors of cervical involvement by tumor.

Cervix Uteri↗

PubMed2000

[Expression of leukemia inhibitory factor in human decidua].

OBJECTIVE: To study the expression and localization of leukemia inhibitory factor (LIF) in human first trimester decidual. METHOD: By immunohistochemical analysis and in situ hybridization, the LIF mRNA and protein expression were observed in 16 cases of human decidua. RESULTS: LIF mRNA and protein expressions were observed in all decidual specimens, the glanduar epithelium showed higher LIF expression than in stromal cells. CONCLUSION: Expression of LIF in human decidua may contribute to embryo implantation, maintenance of placental functions and embryonic growth promation.

Adult↗

PubMed2000

[hCG-PLZF-RARA transgenic mice develop leukemia resembling human chronic myeloid leukemia].

OBJECTIVE: In order to investigate the leukemogenic potential of PLZF-RARA fusion protein in vivo, hCG-PLZF-RARA transgenic mice were generated, in which PIZF-RARA fusion gene was driven by hCG promoter to express in myeloid cells of mice. METHODS: Molecular cloning technology was used to construct hCG-PLZF-RARA gene. The genotype and phenotype of the hCG-PLZF-RARA transgenic mice were analyzed by PCR, RT-PCR, immunofluorescence, morphology of bone marrow (BM) cells, pathology and retinoic acid differentiation assays. RESULTS: Six hCG-PLZF-RARA transgenic mice developed leukemia resembling human chronic myeloid leukemia. TF(tissue factor) was not expressed in BM cells of normal mice nor in mice without the expressed transgene, but it was expressed in mice expessing the transgene. CONCLUSION: PLZF-RARA fusion protein plays a crucial role in leukemogenesis. TF is up-regulated by PLZF-RARA fusion gene.

Animals↗

PubMed2000

[In vitro study of radiation sensitizing effect of hydroxycamptothecin].

OBJECTIVE: To study the radiation sensitizing effect of hydroxycamptothecin (HCPT) on human stomach adenocacinoma and nasopharyngeal carcinoma. METHODS: Human stomach cancer cell line BGC823 and nasopharyngeal cancer cell line CNE-1 were treated in vitro with different doses of radiation alone or radiation followed by HCPT (2 micrograms/ml) for 4 h. Colony forming assay was used for survival fraction analysis. Single-hit multitarget model was used to plot survival curve. RESULTS: The value of D0, Dq and N of BGC823 cells received radiation treatment alone was 1.17 Gy, 1.91 Gy and 5.14 respectively. That of BGC 823 cells received radiation plus HCPT was 0.95 Gy, 0.01 Gy and 1.01 respectively. The sensitization enhanecment (SER) ratio was 1.23 (1.17/0.95). Similar results were obtained for CNE-1 cells treated with radiation alone or in combination with HCPT, with an SER of 1.68. CONCLUSION: HCPT has been shown a radiosensitizing effect in vitro on gastric and nasopharyngeal cancer cells.

Antineoplastic Agents, Phytogenic↗

PubMed2000

[Correlation study of the longest diameter of gastric cardia cancer and its prognosis].

OBJECTIVE: Based on the longest diameter of cancer of gastric cardia, to formulate a new way of staging for better assessment of prognosis. METHODS: A total of 1,536 cases of resected carcinoma of the gastric cardia through left thoracic approach was statistically analyzed using STATA 5.0 software. The survival rate was estimated using life table method. The difference in survival rate between groups was evaluated by the log-rank test. The ratio difference between groups was evaluated by chi 2 test. RESULTS: The longest tumor diameter was divided into 6 grades according to its length: grade I, < 2 cm; grade II, 2 cm-< 4 cm; grade III, 4 cm-< 6 cm; grade IV, 6 cm-< 8 cm; grade V, 8 cm-< 11 cm and grade VI, > or = 11 cm. The 5-year survival rate was 61.5% in grade I, 44.4% in grade II, 26.4% in grade III, 20.5% in grade IV, 16.1% in grade V and 5.7% in grade VI, respectively. There was statistically significant difference (P < 0.05) in 5-year survival rate between 2 grades from grade II to grade VI. CONCLUSION: The longest tumor diameter is of prognostic significance in cancer of gastric cardia.

Adult↗

PubMed2000

[Characteristics of lymph node metastasis of squamous cell carcinoma of thoracic esophagus and its clinical significance].

OBJECTIVE: To study the characteristics of lymph node metastases of squamous-cell carcinoma of thoracic esophagus and its influence on patients' prognosis and find reasonable dissecting approaches of lymph nodes. METHODS: To analyse retrospectively the clinical materials of 243 patients who had undergone resection of squamous-cell carcinoma of thoracic esophagus. RESULTS: Lymph node metastases was found in 110 of the 243 treated patients (45.3%). In 3,813 lymph nodes dissected, metastases existed in 400 (10.5%). The cancer cells disseminated upward and downward to lymph nodes along the esophagus. Tumor differentiation and the depth of tumor invasion were factors influencing lymph node metastases, but the length of tumor was not. The 5-year survival rate of the patients with lymph node metastasis was 16.4%, being much lower than that of patients with no lymph node metastasis (51.9%). The numbers of lymph node metastases had little influence on patients' prognosis. CONCLUSION: Because of the different upward and downward spreading of esophageal cancer cells to the lymph nodes, different lymph node dissecting approaches should be taken. The thoracic, and abdominal regional (two fields) lymph nodes dissection could be appropriate to esophageal carcinoma of the lower thoracic segment, and the cervical, thoracic and abdominal (three fields) lymph node dissection should be done for patients with earlier esophageal carcinoma of upper or middle thoracic segments.

Adult↗

PubMed2000

[Nitric oxide synthase and vascular endothelial growth factor expression in hepatocellular carcinoma and their relation to angiogenesis].

OBJECTIVE: To analyse inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor (VEGF) protein expression in hepatocellular carcinoma (HCC) and their relation to angiogenesis. METHODS: Tissue sections from 71 HCC patients were examined immunohistochemically for protein expression of iNOS, eNOS, and VEGF. Microvessal density (MVD) was counted by endothelial cells immunostained by anti-CD34 antibody. RESULTS: Positive iNOS and eNOS immunostaining was detected in 83.1% and 85.9% of HCC respectively. iNOS and eNOS were not detected in normal hepatic tissue. MVD was 34.3 +/- 1.5/HP and 38.6 +/- 1.6/HP in HCC positive for iNOS and VEGF while it was 31.2 +/- 2.8/HP, and 22.4 +/- 2.0/HP in HCC negative for iNOS and VEGF respectively (P < 0.01). A correlation between NOS expression and VEGF in HCC was not observed. CONCLUSION: iNOS and eNOS may play a role in malignant transformation of post-hepatic cirrhosis. The expression of iNOS and VEGF favors angiogenesis of HCC.

Adult↗

PubMed2000

[Effects of xiaopi yishen oral liquid on hypothalamus-pituitary-adrenal gland-thymus axis in stressed rats].

OBJECTIVE: To investigate the effect of Xiaopi Yishen (XPYS) oral liquid on the rats under repeated forced cold water swimming (RFCWS) stress. METHODS: The changes of serum monoamine, ascorbic acid levels in adrenal gland, monoamine levels in hypothalamus and hypophysis, and thymus index were determined. RESULTS: XPYS lowered the increasing of serum DA, 5-HT, improved the reducing of ascorbic acid in adrenal gland and NE, HVA, 5-HT, 5-HITT in hypothalamus and hypophysis of RFCWS-stressed rats. CONCLUSION: The mechanism of XPYS is in connection with the regulation of hypothalamus-pituitary-adrenal gland-thymus axis.

Animals↗

PubMed2000

[Clinical and experimental study on effect of Chanbei Kechuanping in treating bronchial asthma].

OBJECTIVE: To observe the clinical effect of Chanbei Kechuanping (CBKCP) on bronchial asthma and to explore its mechanism. METHODS: Ninety-six patients of bronchial asthma were randomly divided into two groups, the CBKCP treated group and the control group (treated by Guilong Kechuanning). The changes on symptoms and signs of asthma, pulmonary function, T-lymphocyte subsets, plasma soluble interleukin-2 receptor (sIL-2R), thromboxane B2(TXB2) and 6-keto-prostaglandin F1 alpha(6-keto-PGF1 alpha) were observed before and after treatment. RESULTS: (1) The markedly effective rate and effective rate in the CBKCP treated group were higher than those in the control group. The pulmonary function, including 1 second forced expiratory volume, maximum expiratory flow rate and forced lung expiratory vital capacity were all improved in both groups, but the effect was more obvious in the CBKCP treated group. (2) As compared with the control group, CBKCP showed more obvious effect in lowering sIL-2R, T-lymphocyte subset and raising 6-keto-PGF1 alpha. Experimental study of guinea pig with asthma model showed that CBKCP could markedly prolong the latent time of asthma attack, lower the percentage of mast cells in total cells in the alveoli lavage solution, blood acidophic cell count and degranulation rate of mast cells, and decrease IgE, IL-4 and TXB2 levels as well as increase the 6-keto-PGF1 alpha level. CONCLUSION: CBKCP has favorable therapeutic effect on asthma attack, it might play the role partly by regulating the functional T-lymphocyte subsets, reducing the level of IgE, sIL-2R, IL-4 and TXB2, and increasing the level of 6-keto-PGF1 alpha.

Adolescent↗