Biomedical subjects

S Wang

Publications and source records attributed to S Wang.

At least 289 records · Page 16Linked to original sources

PubMed2001

[Study on the inhibition of tea pigments on the adhesion between monocyte and endothelial cells].

In order to study the effects of tea pigments (TP) on the adhesion between monocyte and endothelial cells induced by oxidized low density lipoprotein(Ox-LDL), the fluorescence activated cell sorter (FACS) and the cell ELISA were applied. The results showed that TP could inhibit the adhesion between monocyte and endothelial cells(P < 0.05), and the expression of inter cell adhesion molecule(ICAM-1) and vascular cell adhesion molecule (VCAM-1) proteins in a dose dependent manner(P < 0.05). The results suggested that the inhibition of TP on ICAM-1 and VCAM-1 expression was one of the mechanisms of its antiadhesion between monocyte and vascular endothelial cells, as well as that of its antiatherosclerosis.

Cell Adhesion↗

PubMed2001

Digital signature technology for health care applications.

BACKGROUND: The personal computer and the Internet have provided many useful services to both health care professionals and the general public. However, security remains a key factor that could limit their further growth potential. METHODS: We reviewed and assessed the potential use of the cryptographic technique to resolve security issues. We also analyzed services available in the current market environment and determined their viability in supporting health care applications. RESULTS: While the cryptographic application has a great potential in protecting security of health care information transmitted over the Internet, a nationwide security infrastructure is needed to support deployment of the technology. Although desirable, it could be cost prohibitive to build a national system to be dedicated for the health care purpose. CONCLUSIONS: A hybrid approach that involves the government's development of a dedicated security infrastructure for health care providers and the use of commercial off-the-shelf products and services by the general public offers the most cost-effective and viable approach.

Computer Security↗

PubMed2001

[The transference and distribution of tritium water in the soybean-soil system].

The isotope trace techniques of simulation contamination were applied to explore the rule of transference and distribution of tritium water in a simulated soybeam-soil ecosystem. The activity ratio of two forms of tritium in plant and soil sample were measured by 50 days simulation experiment. The results showed that when tritium water was entered the soil, it not only was transferred to other compartments in the system, but also vaporized into atmosphere rapidly. Both free water tritium and bound tritium were found in the soybean and the soil. The activity ratio of free water tritium reduced after reaching the maximum (19.4 Bq.g-1 in root, 12.3 Bq.q-1 in stem and leaf) at 6th hour in the soybean. The bound tritium increased slowly. The activity ratio of total tritium in soybean root was upper than those in stem and leaf in the earlier stage, they reach equipoise each other in the later stage. The activity ratio of two tritium in the surface soil reduced continuously. The compartment model of tracer kinetic was applied to imitate the experimental data. The activity ratio of soil Cs = 88.37e-11.847t + 7.38e-0.030t and the activity ratio of soybean Cb = 10.30(e-0.030t - e-11.847t) were gained.

Soil↗

PubMed2001

[The preparation of human single chain Fv antibody specifically against hepatitis C virus NS3 antigen and its application in immunohistochemistry].

OBJECTIVE: Immunohistochemistry identification of human single chain Fv antibody (ScFv) against hepatitis C viral NS3 antigen. METHODS: The recombinant phages were panned by NS3 antigen which was coated on a microtiter plate, after five rounds of biopanning, 66 phage clones were identified specific to NS3 antigen. The affinity and specificity of ScFv were evaluated by ELISA, dot blot hybridization and immunohistochemistry. RESULTS: The data of ScFv-NS3 DNA digestion and DNA sequencing showed that the ScFv gene is composed of 747 bp. ELISA, dot blot hybridization and immunohistochemistry demonstrated that the human single chain Fv antibody against hepatitis C NS3 antigen has a specific combination character with hepatitis C virus NS3 antigen of different sources and paraffin-embedded patients tissues, it didn't react with liver tissue and HBsAg. CONCLUSION: The application of HCV NS3 specific ScFv in immunohistochemistry was successfully achieved.

Cells, Cultured↗

PubMed2001

[The vectorial algorithm for articulate motion of human entities].

The human moving system is defined as a rigid frame, which contains 19 articulate entities. Entity rotates around the father node and its son node is the father of another entity at the next level. The human frame is divided into 5 entity links. Through the vector summation algorithm and along the link, each entity's father nodes are calculated successively, and the vectorial frame of human posture is constructed. With all the entity patterns pasted on the vectorial frame, the picture of human moving posture is drawn.

Algorithms↗

PubMed2001

[A study of association between atherothrombotic brain infarction and HLA-DQA1 peptide binding motifs].

OBJECTIVE: To analyze the hereditary susceptibility for HLA-DQA1 alleles according to trait of multiple genes leading to disease in atherothrombotic brain infarction (ABI). METHODS: HLA-DQA1 alleles in ABI patients (n=81) and healthy controls (n=99) were detected by PCR-SSP techniques. RESULTS: (1)The frequency of HLA-DQA1*0301 was significantly higher in ABI patients. (2)The frequency of HLA-DQA1*0301 was significantly higher in patients with family history of essential hypertension (EH). (3)The frequency of HLA-DQA1*0103 was significantly lower in ABI patients. CONCLUSION: HLA-DQA1*0301 allele might be a correlative gene with hereditary susceptibility of ABI and HLA-DQA1*0301 allele might be a correlative gene in ABI patients with the family history of essential hypertension, whereas HLA-DQA1*0103 allele might be a protective gene in the patients with ABI.

Aged↗

PubMed2001

[Genotypes of transfusion-transmitted virus].

OBJECTIVE: To investigate the genotypes of transfusion-transmitted virus (TTV) in South China. METHODS: One capture probe for all types of TTV from the conserved sequence nt2160 to nt2196 and six varied probes, heterogeneity more than 20% between each other for G1, G2, G3, G4, G5 and G6 type, respectively were synthesized. The primers coming from the conserved sequence of ORF1 were used to amplify TTV DNA from the serums of patients. Microplate sandwich hybridization-ELISA technique was used to detect the genotypes of TTV in 380 hepatitis patients with liver damage. RESULTS: Sixty-one of 380 patients, about 16.0%, were TTV DNA positive, in whom 44 were genotype I (G1), 5 were G2, 10 were mixed infection of G1 and G2, one was G3 and one was G4. Neither G5 nor G6 has been detected. The rate of TTV infection in chronic hepatitis patients was equal to that in acute hepatitis patients. CONCLUSIONS: TTV infection is common in South China. There are four types of TTV. The first genotype was G1, and the second was G2. G5 or G6 has not yet been detected. PCR microplate sandwich hybridization-ELISA has certain value in clinic diagnosis for its specific, sensitive and practicable characters.

DNA Virus Infections↗

PubMed2001

[Treatment of severe hepatitis with artificial liver support system and liver transplantation].

OBJECTIVE: To observe and investigate the efficacy of the hybrid artificial liver support system plus liver transplantation in the treatments of patients with severe viral hepatitis. METHODS: Eight severe viral hepatitis patients with metaphase and advanced stage liver failure received the artificial liver support using a self-command extracorporeal hybrid artificial liver support system and orthotopic liver transplantation after the artificial support for 3-14 days. RESULTS: The liver failure of the 8 patients was controlled by the hybrid artificial liver support effectively. All patients were successfully bridged to orthotopic liver transplantation. Four out of the eight patients survived after transplantation. Four patients died of pulmonary infection or hepatorenal syndrome. CONCLUSIONS: Artificial liver support system combined with liver transplantation can be regarded as an efficient measure for the treatment of metaphase and advanced stage patients of severe viral hepatitis.

Adult↗

PubMed2001

[A simple and reliable spectrophotometric method for quantification of pyridine nucleotides in serum].

Pyridine nucleotides plays an important role in the maintenance of cellular homeostasis and its disturbance also involves in many perturbance of metabolism, so a simple and reliable assay for determination of oxidized and reduced pyridine nucleotides in serum would be significantly necessary in understanding the redox status of body. A novel modified method, which is based on Nisselbam and making use of a cycling enzymatic reaction and spectrophotometric assay to measure the pyridine nucleotides in serum, showed good results. The standard curve has fine linear relationship; the recovery of added standard samples is almost perfect. Twenty-seven samples from 27 normal subjects were examined by the method. The results were: NADPH 8.385 +/- 1.516 nmol/ml, NADP+ 3.624 +/- 0.985 nmol/ml, and NADPH/NADP+ 2.3612 +/- 0.8057; no significant difference in the variables was found between the male and female. This is a sensitive, simple, reliable and easy-practicing method for oxidized and reduced pyridine nucleotides assay.

Adult↗

PubMed2001

[Inhibitory effects of phosphorothioate antisense oligonucleotides on gene expression controlled by HCV 5'NCR in nude mice xenograft].

OBJECTIVE: To evaluate the activity in vivo of 3 phosphorothioate antisense oligonucleotides, HCV363, HCV279 and HCV349 using nude mice xenograft models based on the establishment of HCV 5' NCR transgenic cellular model (HepG2.9706). METHODS: Female BALB/C nude mice, aged 4 to 6 weeks and weighing around 20g, were implanted s.c. with 100mul (106 cells) of the HepG2.9706 cells suspension in the lower-back region. In approximate 1 weeks, the animals were randomly grouped and intraperitoneally administrated the antisense drugs at 10 mg/kg body weight. RESULTS: HCV363, HCV279 and HCV349 had obvious sequence-specific inhibitory effects on luciferase expression controlled by HCV 5' NCR in xenograft cells with the inhibitory rates of 80.4%, 78.6% and 47.9%, respectively. The effects of three different concentrations (5, 10, 20 mg/kg body weight) of HCV363 indicated that HCV363 increased the inhibitory activities on luciferase expression following the concentration raise and its inhibitory rate was up to 82.7%. CONCLUSIONS: This study suggests that antisense oligonucleotides may provide a novel therapeutic approach to the treatment of HCV infection.

Animals↗

PubMed2001

Cr (VI) increases tyrosine phosphorylation through reactive oxygen species-mediated reactions.

While Cr (VI)-containing compounds are well established carcinogens, the mechanisms of their action remain to be investigated. In this study we show that Cr (VI) causes increased tyrosine phosphorylation in human lung epithelial A549 cells in a time-dependent manner. N-acetyl-cysteine (NAC), a general antioxidant, inhibited Cr (VI)-induced tyrosine phosphorylation. Catalase, a scavenger of H2O2, sodium formate and aspirin, scavengers of hydroxyl radical (*OH), also inhibited the increased tyrosine phosphorylation induced by Cr (VI). SOD, an inhibitor of superoxide radical (O2*-), caused less inhibition. ESR study shows that incubation of Cr (VI) with the A549 cells generates *OH radical. The generation of radical was decreased by addition of catalase and sodium formate, while SOD did not have any inhibitory effect. Oxygen consumption measurements show that addition of Cr (VI) to A549 cells resulted in enhanced molecular oxygen consumption. These results indicate that Cr (VI) can induce an increase in tyrosine phosphorylation. H2O2 and *OH radicals generated during the process are responsible for the increased tyrosine phosphorylation induced by Cr (VI).

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2001

On the mechanism of Cr (VI)-induced carcinogenesis: dose dependence of uptake and cellular responses.

Cr (VI) compounds are widely used industrial chemicals and are recognized human carcinogens. The mechanisms of carcinogenesis associated with these compounds remain to be investigated. The present study focused on dose-dependence of Cr (VI)-induced uptake and cellular responses. The results show that Cr (VI) is able to enter the cells (human lung epithelial cell line A549) at low concentration (< 10 microM) and that the Cr (VI) uptake appears to be a combination of saturable transport and passive diffusion. Electron spin resonance (ESR) trapping measurements showed that upon stimulation with Cr (VI), A549 cells were able to generate reactive oxygen species (ROS). The amount of ROS generated depended on the Cr (VI) concentration. ROS generation involved NADPH-dependent flavoenzymes. Cr (VI) affected the following cellular parameters in a dose-dependent manner, (a) activation of nuclear transcription factors NF-kappaB, and p53, (b) DNA damage, (c) induction of cell apoptosis, and (d) inhibition of cell proliferation. The activation of transcription factors was assessed by electrophoretic mobility shift assay and western blot analysis, DNA damage by single cell gel electrophoresis assay, cell apoptosis by DNA fragmentation assay, and cell proliferation by a non-radioactive ELISA kit. At the concentration range used in the present study, no thresholds were found in all of these cell responses to Cr (VI). The results may guide further research to better understand and evaluate the risk of Cr (VI)-induced carcinogenesis at low levels of exposure.

Antioxidants↗

PubMed2001

Molecular mechanisms of metal toxicity and carcinogenesis.

Many metals and metal-containing compounds have been identified to be potent mutagens and carcinogens. Recently, a new sub-discipline of molecular toxicology and carcinogenesis has been developed. The combination of newly developed molecular techniques and free radical approach makes it possible to insightfully examine metal-induced carcinogenesis in precise molecular terms so that intricate biological interrelationships can be elucidated. In consideration of the increased amount of new findings deciphered by utilizing these new methods, the 1st Conference on Molecular Mechanisms of Metal Toxicity and Carcinogenesis was held. In this conference, more than 50 scientists from nine countries presented their novel discoveries concerning metal-induced carcinogenesis, delineated molecular mechanism of metal carcinogenesis, and proposed novel therapeutic intervention and prevention strategies. This article reviews some of the state-of-the-art information presented at the meeting regarding the molecular mechanisms of metal cytotoxicity and carcinogenesis.

Apoptosis↗

PubMed2001

Cr (VI) induces cell growth arrest through hydrogen peroxide-mediated reactions.

Cr (VI) compounds are widely used in industries and are recognized human carcinogens. The mechanism of carcinogenesis associated with these compounds is not well understood. The present study focused on Cr (VI)-induced cell growth arrest in human lung epithelial A549 cells, using flow cytometric analysis of DNA content. Treatment of the cells with Cr (VI) at 1 microM caused a growth arrest at G2/M phase. An increase in Cr (VI) concentration enhanced the growth arrest. At a concentration of 25 microM, Cr (VI)-induced apoptosis became apparent. Superoxide dismutase (SOD) or sodium formate did not alter the Cr (VI)-induced cell growth arrest. While catalase inhibited growth, indicating H2O2 is an important mediator in Cr (VI)-induced G2/M phase arrest. Electron spin resonance (ESR) spin trapping measurements showed that incubation of cells with Cr (VI) generated hydroxyl radical (*OH). Catalase inhibited the *OH radical generation, indicating that H2O2 was generated from cells stimulated by Cr (VI), and that H2O2 functioned as a precursor for *OH radical generation. The formation of H2O2 from Cr (VI)-stimulated cells was also measured by the change in fluorescence of scopoletin in the presence of horseradish peroxidase. The mechanism of reactive oxygen species generation involved the reduction of molecular oxygen as shown by oxygen consumption assay. These results support the following conclusions: (a) Reactive oxygen species are generated in Cr (VI)-stimulated A549 cells through reduction of molecular oxygen, (b) Among the reactive oxygen species generated, H2O2 played a major role in causing G2/M phase arrest in human lung epithelial cells.

Antioxidants↗

PubMed2001

[Analysis of mass minimization of Thermoelectric Integrated Membrane Evaporation Subsystem in waste water processing].

OBJECTIVE: To minimize in the system level the designed mass of Thermoelectric Integrated Membrane Evaporation Subsystem (TIMES) of Environment Control Life Support System (ECLSS) in manned spacecraft, when the requirement of the production rate of fresh water and its hygiene is fulfilled. METHOD: According to the characteristics of the operational process of TIMES, the physical and mathematical model for fluid flow, heat transfer and mass composition in its main parts were established to investigate numerically the relation between the system mass and those parameters associated with the structure and operation of the system. RESULT: The system mass depended not only on the structural parameters and operational parameters of TIMES, but also on the operational characteristics of power subsystem and thermal control subsystem. The relative mass covered a large part of the system mass. CONCLUSION: There existed an optimum of the number of thermoelectric cooling parts and flow rate of circular waste water of the TIMES when the designed system mass was minimum. Moreover, higher condensation pressure in the system contributed to lower system mass.

Ecological Systems, Closed↗

PubMed2001

[Isozyme analysis of Gastrodia elata f. elata and G. elata f. glaucca and their hybrid].

Peroxidase(POX) isozyme analysis of Gastrodia elata f. glaucca, G. elata f. elata and its hybrid were carried out. The results indicated that shoot apex meristem was optimal material for POX analysis and the determination of the hybrid. The zymogram hands were stable and clear. POX isozyme zymogram of the hybrid F1(H x W) represented the visible supplement relation between Gastrodia elata f. elata and Gastrodia elata f. glaucca.

Gastrodia↗

PubMed2001

[Radiologic features of desmoplastic ameloblastoma].

OBJECTIVE: To investigate the radiologic features of desmoplastic ameloblastoma. METHODS: The radiologic characteristics of 15 cases desmoplastic ameloblastoma which were diagnosed pathologically were analyzed retrospectively, and compared with solid or multicystic ameloblastoma. RESULTS: Desmoplastic ameloblastoma were mainly located in anterior and (or) premolar region of maxilla and mandible. There existed three features radiologically. 1. unilocular formation containing varying amounts of radiopaque islands or strands material. 2. multilocular destruction containing irregular or line-like radiopaque areas. 3. mixed destruction showing plxiform radiopaque material and unilocular change. Typical microscopic features were irregular and compressed epithelial islands or strands interspersed among dense fibrous connective tissue stroma. CONCLUSIONS: The desmopleatic ameloblastoma is a new type of ameloblastoma and exhibits some special characteristics radiologically and pathologically. It should be differentiated from osteofibroma and odontogenic myxoma.

Adolescent↗

PubMed2001

[Immunohistochemical and ultrastructural study of basement membrane in oral verrucous carcinoma].

OBJECTIVE: To study the immunohistochemical alteration of basement membrane (BM) type IV collagen and laminin in oral verrucous carcinoma and its BM ultrastructural variations. METHODS: 16 cases of oral verrucous carcinoma (OVC), 10 cases of oral squamous cell carcinoma (OSCC) and 9 cases of oral mild to severe epithelial dysplasia (OMSD) were studied by using a immunohistochemical S-P method, and the results were analyzed by quantitative method. 3 cases of OVC were observed by TEM. RESULTS: The BM in OVC was thicker than in OSCC and OMSD. TEM found the basal lamina in some areas showed a marked reduplication. The BM in OVC was generally intact (13/16), whereas in OSCC it was mostly discontinuous (9/10), especially around the neoplasm front or the small cord consisted of a few cells, and mostly continuous in OMSD (6/9). There was a stromal inflammatory infiltration around tumor nests for all the oral lesions, but it was much heavier in OVC than that in OSCC and OMSD (P < 0.05). There was a positive correlation between intraepithelial lymphocytic infiltration and the BM continuity for OVC(P < 0.01). CONCLUSIONS: The more continuous BM and the heavier inflammatory infiltration in the connective tissue of OVC may be related to its biological behavior.

Basement Membrane↗