Biomedical subjects

H Wang

Publications and source records attributed to H Wang.

At least 955 records · Page 53Linked to original sources

PubMed2000

[Modulation of prolactin (PRL) secretion in human uterine decidual cells at early pregnancy].

Decidualization is essential for implantation of embryo and maintenance of pregnancy in human. The mechanism of decidualization was investigated in this study by regulation of prolactin (PRL) release in cultured human decidual cells during first trimester of gestation. Progesterone significantly stimulated PRL secretion, but the effect of estrogen depended on its concentration, which was ineffective at the physiological level (10( 9) mol/L) but suppressed the stimulatory effect of progesterone at higher levels. Thus adequate proportion of estrogen and progesterone is important for the decidualization. Furthermore, RU486 dramatically inhibited PRL release, suggesting that the effect of progesterone was mediated, at least in part, through its receptor. cAMP at concentration higher than 10( 5) mol/L significantly increased PRL secretion, suggesting that the cAMP signal pathway might be involved in decidualization.

Cells, Cultured↗

PubMed2000

[Studies on metal porphyrins as two-functional mimic of enzyme].

In this study, four metal porphyrins (tetraphenylporphyrinesulfonatoiron, tetraphenylporphyrinesulfon-atocopper, tetraphenylporphyrinesulfonatomanganese, and tetraphenyl porrphyrinesulfonatocobalt) were used as dual function mimicry of superoxide dismutase (SOD) and catalase (CAT). The first function, scavenging O2.-, has been proved by using riboflavine-methionine photoreduction method in the concentration range of 10(-5)-10(-6) mol/L. The second function, scavenging H2O2, has been demonstrated by means of spectrophotometry, and the percentage of decomposing H2O2 increases with the concentration of the imitating compounds. Metal porphyrins, SOD and CAT were measured by the liver homogenate technique of mice and the results showed that they had obvious action of decreasing the lipid peroxidation. Tetraphenylporphyrinesulfonatomanganese was measured by isolated ischemia reperfusion heart of rats. The results indicated that the Mn-TPPS4 could reduce the damages of active oxygen and had evidently protective effects on isolated ischemia-reperfusion mocardium of rats.

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

[An adenosine triphosphate bioluminescence assay for detecting the number of living cells].

The method for detecting the number of living cells was studied. Using an adenosine triphosphate (ATP) bioluminescence assay, the present authors reported a perfect linear relationship between lg ATP concentrations and lg luminescence counts (r = 0.9963) as well as a relationship between lg number of cells and lg ATP luminescence counts (r = 0.9922). The detectable cells ranged from 10(2) to 10(6) cells/ml, the coefficients of variation 1-3%. This method is simple, accurate and sensitive and has a high reproducibility.

Adenosine Triphosphate↗

PubMed2000

[Determination of flavonoids in Ginkgo biloba L. leaves from different producing areas].

OBJECTIVE: To compare the contents of flavonoids in the leaves of Ginkgo biloba gathered from 35 producing areas. METHODS: Separating and determining 3 flavonoid aglycones, quercetin, kaempferol and isorhamnetin, by high performance liquid chromatography, and there by calculating the total contents of flavonoids. RESULTS: The contents of flavonoids in the leaves of G. biloba gathered from different producing areas are different, but in those gathered from Pizhou, Zheng'an Xing'an, Anlu, etc. appear higher.

Flavonoids↗

PubMed2000

[Effect of L-dicentrine on contraction of rat stomach muscle strips].

OBJECTIVE: To study the effect of L-dicentrine on the contraction of rat stomach muscle strips induced by 5-HT, histamine K+ and Ca2+. METHOD: In-vitro experimenting on rat stomach muscle strips. RESULTS: The contraction of the strips induced by 5-HT histamine K+ and Ca2+ after high K+ depolarization was markedly inhibited by L-dicentrine or papaverine, showing a non-competitive antagonism. The contraction induced by 5-HT was inhibited by L-dicentrine in Ca2+ free solution. L-Dicentrine inhibited the contraction induced by 5-HT, depending on Ca2+ released from the intracellular store. When the Ca2+ concentration in both solutions was restored, L-dicentrine did not influence the contraction significantly. CONCLUSION: L-Dicentrine could relax the rat stomach smooth muscle. In rat stomach smooth muscles there exist 5-HT receptors.

Animals↗

PubMed2000

[The effect of soft tissue repairing at different times on the union of type III b tibial fracture].

OBJECTIVE: To investigate the effect of soft tissue repairing at different times on the union of type III b tibial fracture. METHODS: From January 1987 to January 1999, seventy-six type III b tibial fractures were divided into 3 groups: early group(0 to 7 days), subacute group(8 to 30 days), late group(more than 30 days) according to the time of soft tissue repairing. The morbidity rates of complications such as infection, nonunion as well as the time to union were compared respectively. RESULTS: Followed up for 10 to 36 months (averaged 24 months), the infection and nonunion rates of early group were lower than that of subacute and late groups(P < 0.01), the average time of fracture union of early group was less than that of subacute and late groups. CONCLUSION: Early soft tissue repairing can decrease the complications and the time to union of Type III b tibial fracture obviously. The time of "early" should be limited in one week and as soon as possible.

Accidents, Traffic↗

PubMed2000

[Effects of deoxynivalenol on proliferation and tumor necrosis factor-alpha secretion of human peripheral blood mononuclear cells in vitro].

Deoxynivalenol (DON) is one of the most common contaminating mycotoxins in food at high risk areas of esophageal carcinoma in China. The effects of DON on proliferation and tumor necrosis factor-alpha (TNF-alpha) secretion of human peripheral blood mononuclear (HPBM) cells in vitro were determined with flow cytometric (FCM) analysis, cell counting, MTT bioassay and ELISA method respectively. FCM analysis revealed that after HPBM were prestimulated with PHA for 48 h, the proliferation indexes(PI) of the cells treated with low concentration of DON (50-500 ng/ml) for 6 h were all dramatically lower than that of normal control (19.80%-26.01% vs 37.84%), while the PI of cells treated with high concentration of DON(1000-2000 ng/ml) for 24 h were higher than that of normal control (35.74%-34.37% vs 22.85%). Cell number counting and MTT bioassay results showed that at the presence of PHA, DON inhibited the proliferation of HPBM. Double antibody sandwich enzyme linked immunosorbent assay (ELISA) showed that the secretion of TNF-alpha in cells treated with DON(500-1000 ng/ml) was significantly lower than that in the control (P < 0.01). The results suggested that DON could either inhibit or stimulate cell proliferation depending on active time, concentration and PHA stimulation. In general, DON mainly inhibited the proliferation of HPBM and decrease TNF-alpha secretion in vitro. Thus, DON might have some negative impacts on human immunological system.

Cell Division↗

PubMed2000

[A study of HSP70 and NF in brain contusion timing].

The changes of HSP70 and NF after brain contusion were studied by the immunohistochemistry method. HSP70 and NF were seen at 30 min after injury around the wound area, but faded away after 12-24 h. The result suggests that these two proteins could be used to estimate brain contusion time, to diagnose brain wound and to distinguish antemortem and postmortem brain contusion.

Animals↗

PubMed2000

[Immunohistochemical study of type I and type II collagen in the remodelling of the supraosseous tissue of mandibular condyle].

OBJECTIVE: Previous studies focused on the pathological changes of the supraosseous tissue of mandibular condyle (STMC), but little is known about extracellular matrix during the remodelling activity of temporomandibular joint (TMJ). This study will examine the characteristics of type I and type II collagen during this process. METHODS: The animal model was established by extracting the left lower molars of adult rabbits. Temporomandibular joints of two sides were taken after 2 weeks, 1 month and 3 months respectively, and embedded in paraffin. Then 5 microns-thick sections were cut and processed for immunohistochemistry and haematoxylin-eosin staining. An immunohistochemical ABC method was used to determine the local changes of type I and type II collagen. The positive cells were counted in order to analyze quantitative changes. RESULTS: After loss of teeth from 2 weeks to 3 months, the number and arrangement of chondrocytes changed. Some chondrocyte clusters were also observed in the non-extraction side of TMJ. Most STMC cells stained positively with anti-type I collagen, but weakly in chondrocytes and hypertrophic chondrocytes. On the other hand, type II collagen only existed in chondrocytes and some hypertrophic chondrocytes. The expression of type I collagen decreased after 2 weeks and became stronger after 1 and 3 months, furthermore distributed unevenly in STMC. Some hypertrophic chondrocytes in the non-extraction side showed strong positive staining with anti-type I collagen. Type II collagen in two sides decreased after 2 weeks, then became stronger after 1 and 3 month, but the whole level was less than that of the control group. Expressions of two kinds of collagen were compared between two sides. Type I collagen in the non-extraction side was stronger than that in the extraction side, while type II collagen had an opposite result. CONCLUSION: Adult rabbits have a limited remodelling ability, and the synthesis and secretion of type I and type II collagen will change when the remodelling is beyond a proper extent, which will lead to impaired resistance and elasticity of fibrocartilage.

Animals↗

PubMed2000

[The relationship between GPx activity in gingival fluid and clinical parameters of adult periodontitis].

OBJECTIVE: To study the relationship of glutathione peroxidase (a natural FR scavenger) in gingival cervical fluid (GCF) of patients with periodontitis. METHODS: GCF was collected from 44 sites of 23 patients with adult periodontitis. The volume of GCF was measured with Periotron 8000. GCF-GPx activity was determined by DTNB methods before and after treatment, and the periodontal parameters GI, PD and AL were recorded. RESULTS: GCF-GPx activity was negatively correlated with PD and AL (P < 0.01, P < 0.005), but was not correlated with GI (P > 0.05). After treatment, clinical parameters decreased while GCF-GPx activity increased (P < 0.001), but the increment of GCF-GPx activity showed no correlation with the base level and the changes of clinical parameters. CONCLUSION: The imbalance between FR's production and scavenging might be an important pathological factor of periodontal diseases, and GCF-GPx might be a promising indicator of periodontal status.

Adult↗

PubMed2000

[Informatics of dental medicine].

Dental informatics is a newly developed discinpline which is integrated by modern stomatology, computer sciences and informatics. In this paper, the concept, importance, basic principle and contents were discussed in details. The relationship among dental informatics and related sciences, the formation and history of dental informatics were also described in this paper.

Medical Informatics↗

PubMed2000

[Clinical study of direct digital radiography in caries detection].

OBJECTIVE: Direct digital radiography is a computer-based image technique, the purpose of this paper is to investigate possible usage of direct digital radiography-radio visiography (RVG) in caries detection in clinic. METHODS: A human head model with teeth was used to establish the operative exposure time for RVG in vitro, then RVG images for normal and carious tooth were obtained in vivo and were compared with conventional E-speed film in image quality and diagnostic accuracy. RESULTS: The optimal exposure time for RVG image was obtained, and the exposure time was different in each tooth quarter. The acceptable rate of image quality and diagnostic accuracy of RVG was statistically equivalent to that of E-speed film (P > 0.05), however, the excellent rate of RVG was statistically superior to that of E-speed film (P < 0.05). CONCLUSION: The conventional X-ray will be substituted by RVG in caries detection in clinic.

Adolescent↗

PubMed2000

[An evaluation of adenosine triphosphate bioluminescence assay for tumor in vitro chemosensitivity testing].

This study was aimed at the feasibility of using ATP-bioluminescence assay for tumor in vitro chemosensitivity testing. With the use of this assay, the authors determined dose-response curve in mouse fibroma cell line L929 treated with chemotherapeutic agents, and investigated the different in vitro responses of 6 ovarian carcinomas (5 from fresh tumor tissues, 1 from ascites) treated with etopside, cis-plating, 5-fluorouracil and adriamycin. The results showed that the coefficients of variation for triplicate assays ranged from 1.2% to 15.8% which means high reproducibility of the assay. The single cell suspension (including < 30 cells clusters) could be separated from tissue fragments by means of enzyme cocktail (collagenase, Dnase, pronase). The viable cells were over 90%. This study demonstrates that ATP-bioluminescence assay is a sensitive, reliable and efficient method for tumor chemosensitivity testing. In this connection, the correlation between in vitro drug sensitivity and in vivo patient response is worth further studying.

Adenosine Triphosphate↗

PubMed2000

[Conditions of enzyme production and properties of alkaline lipase by Streptomyces Z94-2].

An alkaline lipase producing strain streptomyces Z94-2 was selected from 152 lipase producer, The optimal medium composition for the producing lipase is (g/L): soybean meal 30, urea 10, dextrin 10, KH2PO4 0.5, NaCl 1, MgSO4.7H2O 0.5, AEO9 (nonionic surfactant) 1. The optimal conditions for lipase producing are initial pH 9.5-10.0, shaken at 26 degrees C, for 48 h, a maximal lipase activity of reached 596 (u/mL). The optimal activity at pH 9.8 and at 37 degrees C, respectively. The lipase was stable at pH 8.6-10.2 and below 60 degrees C, and the lipase was highly activated by 0.14 mol/L CaCl2.

Calcium Chloride↗

PubMed2000

[Interaction between biofilm formed by Pseudomonas aeruginosa and antibacterial agents].

UNLABELLED: We hypothesized that bacterial biofilm formation could be an important factor that make some infection intractable. Interaction of P. aeruginosa biofilm with antibactial agents was examined in vitro. METHODS: P. aeruginosa incubated for 6 days in a saline-teflon system formed biofilm on the surfaces of the teflon piece. The biofilm were characteried by dense colonization of bacteria and thick membranous structure that covered the colonies, it was observed with a scanning electron microscopy. CPFX, CAM, ROX and Herba Andrographitis were added to the biofilm bacteria. RESULTS: The rate of survial of the floating bacteria decreased to 0.02% after 4 hours of contact with 2MIC of Ciprofloxacin (CPFX), but that of biofilms was 41% When 10 micrograms/mL of Clarithromycin (CAM per mL was combined with CPFX, the survial rate for the biofilm bacteria decreased to 0.2%. When 12 micrograms/mL of Roxithromycin (ROX) was combined with CPFX, the survial rate for the biofilm bacteria decreased to 0.5%. When 0.05 g of Burm. f. per mL was combined with CPFX the survial rate for the biofilm bacteria decreased to 2.7%. CONCLUSION: We conclude that biofilm bacteria are much more resistant to CPFX than the floating bacteria. The combination of CPFX and CAM, ROX HA were more effective in decreasing the biofilm bacteria survial rate than CPFX alone. The results suggest that the combination of CPFX and CAM, ROX, HA can be one of the therapeutic manauvers against biofilm bacteria.

Anti-Bacterial Agents↗

PubMed2000

[Selection and recombinant expression of an immunodominant B cell epitope of HIV gp41].

A novel method was designed for disease-specific B cell epitope mapping and epitope expression in E. coli. A phage library displaying random dodecamers was biopanned first with human total IgG antibodies against HIV-1, and then non-specific phages were subtracted by HIV(-) polyclonal antibodies. After three rounds of screening, the positive phages were tested in an ELISA for their reactivity with HIV(+)-IgG and HIV(-)-IgG antibodies. Phages that showed positive reactivity with HIV(+)-IgG, but negative to HIV(-)-IgG, were selected and their displayed peptides were determined by DNA sequencing. All the 13 positive clones sequenced displayed five kinds of peptides (SPKCLGKLLCAF, THQCLGKLQCGV, SCSAKFTCTTQI, KSDCSARFMCSV, DCLKQWACEWSR) that have homology to the HIV-1 gp41(602GCSGKLICTTNV613), demonstrating there is a dominant epitope in the region.

Enzyme-Linked Immunosorbent Assay↗

PubMed2000

[Noninvasive estimation of tissue temperature in hyperthermia using diagnostic ultrasound].

Hyperthermia is one of the important techniques in tumor treatments. Temperature estimating and monitoring is the key technique in hyperthermia. In this paper, a new nonivasive temperature estimation method based on backscattered ultrasonic power is introduced. Compared with the techniques based on echo-shift and frequency-shift, this method has its advantage for application. The change of backscattered power caused by the temperature change is conspicuous and easy to measure. The new techniques and difficulties in this field are also addressed.

Body Temperature↗