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Biomedical subjects

H Wang

Publications and source records attributed to H Wang.

At least 379 records · Page 21Linked to original sources
PubMed2001

Total waste-load control and allocation based on input-output analysis for Shenzhen, south China.

The general objective for this paper is to reveal the dynamic relationships between the rapid economic development, water pollution and the subsequent waste-load allocation in different economic sectors through a case-study in Shenzhen City, South China. Two-objective analysis model was employed based on the input-output table for Shenzhen with the full consideration of various constraints in local area. The improved Tchebycheff procedure was used for obtaining the solutions. The predictions were made on economic development and pollutants from wastewater in different sectors and different planning years. The present study allows for the consideration of the economic structural adjustment. It is found that the current situation of economic structure is generally good and is subject to further adjustment in Shenzhen, although it has undergone the rapid development in the past 18 years. When the maximum Gross Domestic Production and the minimum Chemical Oxygen Demand are chosen as the two objectives subject to other constraints, the harmonized results indicated a scheme that claims substantial reduction of polluting effluences in Shenzhen while closely keeping the economic growth rate as planned.

China↗
PubMed2001

The effect of nitric oxide inhibition on blood pressure depends on rat strain.

BACKGROUND: Nitric oxide is a continuously released endothelium-derived vasodilator and plays an important role in the maintenance of blood pressure (BP). Rat strains appear to differ in their resting BP and their response to the intravenous administration of N(omega)-nitro-l-arginine methyl ester (l-NAME), a nitric oxide synthase inhibitor. The presence of diabetes and hypertension also leads to differences in BP responses to l-NAME. We postulated that the contribution of NO to resting BP varies between rat strains and certain strains may be more sensitive to the effects of NO blockade. METHODS: Blood pressure was continuously measured using a carotid arterial catheter and the responses to l-NAME were compared in anesthetized Lewis and Sprague-Dawley rats during a 2-h control period and a 2-h experimental period. l-NAME was given by a 50 mg/kg bolus followed by a 10 mg/kg/h infusion via a mesenteric vein. RESULTS: During the control period, the Lewis animals had lower systolic and diastolic BPs of 103 +/- 1 and 80 +/- 1 mm Hg compared with 127 +/- 1 and 105 +/- 1 mm Hg measured in Sprague-Dawley rats (P < 0.01). Although l-NAME infusion increased systolic BP in both strains compared with control values (P < 0.00005), the magnitude was significantly greater in Sprague-Dawley than Lewis animals (P = 0.0142); additionally, the BP was unstable in the Lewis animals. Furthermore, pulse pressure decreased during l-NAME in Lewis animals but increased in Sprague-Dawley animals (P < 0.00005). There were no significant changes in serum concentrations of aspartate transaminase nor of nitrite plus nitrate after l-NAME in either group. CONCLUSION: These results indicate that the effect of l-NAME on systemic BP differs markedly in Sprague-Dawley and Lewis rats, suggesting that the role of nitric oxide in regulation of resting vascular resistance may differ significantly between these rat strains. Rat strain is an important consideration for valid comparisons between studies.

Animals↗
PubMed2001

Expression of the amino-terminal domain of platelet glycoprotein Ib alpha: exploitation of a calmodulin tag for determination of its functional activity.

Platelet glycoprotein (GP) Ibalpha is a component of the GPIb-IX receptor complex, which is involved in multiple physiological and pathological processes, including platelet adhesion at sites of vascular injury, thrombin binding, Bernard-Soulier syndrome, platelet-type von Willebrand disease, and immune-mediated thrombocytopenias. The amino-terminal domain of approximately 300 residues of GPIbalpha mediates both normal biological function (by providing the sites for direct ligand interaction) and aberrant function (through amino acid substitutions). To investigate the molecular interactions mediated by this region of GPIbalpha, we have developed a recombinant baculovirus to facilitate its expression as a calmodulin fusion protein from insect cells. By employing the calmodulin tag, the fusion protein could be obtained at >90% purity after a single isolation step at yields of 8 mg/L of insect cell medium (purified fusion protein). The recombinant GPIbalpha fragment was shown to be posttranslationally sulfated and glycosylated, although its glycosylation differed from that of the equivalent GPIbalpha fragment isolated from human platelets. The differential glycosylation, however, did not affect the function of the recombinant GPIbalpha fragment in either von Willebrand factor (vWf) or thrombin binding as these were both found to be identical to those of the same-length GPIbalpha fragment derived from human platelets. The calmodulin tag was also exploited in the development of assays to measure directly vWf and thrombin binding, since it did not interfere with either, demonstrating the feasibility for the use of this soluble receptor fusion protein in detailed biophysical assays to investigate the molecular mode of binding of platelet glycoprotein Ibalpha to these ligands.

Animals↗
PubMed2001

The study on intramyocardial calcium overload and apoptosis induced by coxsackievirus B3.

The isolated cardiac myocytes of rats were immediately infected by cosackievirus B3 (CVB3) to investigate the effects of such procedure on the cell cycle, apoptosis and intracellular ionized calcium (Ca2+ i) of cardiac myocytes. Newborn Balb/c murine cardiac myocytes were cultivated, then infected by CVB3. Intracellular Ca2+ i was measured by flow cytometer. The calcium in the medium for culturing cardiac myocytes was detected by using atom absorb spectrum test. It was found that CVB3 could markedly inhibit the differentiation and proliferation of the infected cardiac myocytes and induce the apoptosis. The intracellular Ca2+ i level in the infected group was significantly higher than in the control group (P < 0.01). The calcium concentration in the medium for culturing cardiac myocytes in the infected group was significantly lower than in the control group (P < 0.05). It was suggested that the apoptosis and intracellular calcium overload of the CVB3-affected cardiac myocytes are likely to play an important role in the pathogenesis of viral myocarditis.

Animals↗
PubMed2001

The study on the relationship between serum vascular endothelial growth factor and proteinuria in adriamycin-induced nephrotic rats.

To study the relationship between serum vascular endothelial growth factor (VEGF) and proteinuria in adriamycin-induced nephrotic rats, a rat model of adriamycin-induced nephrotitis was developed by injection of adriamycin into a tail vein in a rat. At different time points, 24-h urinary protein excretion was measured by using Coomassie brilliant blue method and the serum VEGF levels detected by using ELISA assay. The interventional effect of VEGF on this model was observed. The results showed that: (1) The adriamycin-induced nephrotic syndrome rat model was developed successfully; (2) Serum VEGF levels and proteinuria were significantly increased at 7th day after intravenous injection of adriamycin. There was a positive correlation between serum VEGF levels and 24-h urinary protein excretion (r = 0.67, P < 0.05). (3) The 24-h urinary protein excretion was significantly increased in the rats receiving administration of VEGF (P < 0.05). It was concluded that VEGF might play an important role in the pathogenesis of proteinuria in adriamycin-induced nephrotic rats.

Animals↗
PubMed2001

Studies on metal phthalocyanine as a dual functional mimic enzyme.

Four phthalocyanines (iron tetracarboxylphthalocyanine, copper tetracarboxylphthalocyanine, manganese tetracarboxylphthalocyanine, cobalt tetracarboxylphthalocyanine) were used as dual functional mimic enzymes of superoxide dismutase (SOD) and catalase (CAT). The first function, eliminating O2-, was proved by using riboflavine-methionine photoreduction method in the concentration range of 10(-5) to 10(-6) mol/L. The second function, clearing out H2O2, was demonstrated by means of spectrophotometry with the decomposing percentage being increased with the increase of the concentration of the imitating compounds. Measurements of metal phthalocyanines, SOD and CAT by the liver homogenate technique of mice showed that they had obvious action of decreasing the lipid peroxidation.

Animals↗
PubMed2001

Spectrofluorimetric determination of thiols by use of N[P-(2-benzoxazolyl)phenyl]maleimide.

The weak fluorescence of N-[P-(2-benzoxazolyl)phenyl]maleimide (BOPM) can be greatly enhanced by thiol-containing compounds. A sensitive and simple spectrofluorimetric method based on the use of BOPM has been developed for the determination of thiols such as cysteine (Cys) and reduced glutathione (GSH). Calibration plots were linear in the concentration range from 0 to 1.6 x 10(-7) mol L(-1) for Cys and 0 to 1.7 x 10(-7) mol L(-1) for GSH. The detection limits (3a) were 2.36 x 10(-10) mol L(-1) for Cys and 1.49 x 10(-10) mol L(-1) for GSH. Many other amino acids (present at 100-fold greater concentrations) did not interfere with the determination. The proposed method has been used for the determination of Cys in protein hydrolysate and cystine electrolyte or GSH in serum, with recoveries of 95.4-103.7%.

Journal Article↗
PubMed2001

Identification of a new gene product of PKIbeta by HPLC-ESIMS.

An identification method using high-performance liquid chromatography combined with electrospray mass spectrometry (HPLC-ESIMS) has been developed to verify an expressed gene product of kinase inhibitor (PKIbeta). This protein was expressed in this university for the first time from a newly cloned gene in the cDNA library of human fetal brain. The measured MW (8468.9 Da) of PKIbeta-78 was consistent with expectations. The gene product of PKIbeta-78 was monitored by ESIMS to ensure there was no mis-expressed PKIbeta-70 in the process of gene engineering. The peptide mapping of PKIbeta-78 and its partial sequence were, furthermore, determined. By database searching based on the experimental MWs and partial sequences provided, it was verified that this gene product is a new protein. The pseudosubstrate site and leucine-rich site for the function region of PKIbeta-78 are also confirmed.

Amino Acid Sequence↗
PubMed2001

Interaction between the melanocortin-1 receptor and P genes contributes to inter-individual variation in skin pigmentation phenotypes in a Tibetan population.

The melanocortin-1 receptor (MC1R) and P gene product are two important components of the human pigmentary system that have been shown to be associated with red hair/fair skin and cause type II oculocutaneous albinism, respectively. However, their contribution to inter-individual variation at the population level is not well defined. To this end, we genotyped 3 single nucleotide polymorphisms (SNPs) in the MC1R gene (Arg67Gln, Gln163Arg, Val92Met) and 2 SNPs in the P gene (IVS 13-15 and Gly780Gly) in 184 randomly ascertained Tibetan subjects, whose skin color was measured as a quantitative trait by reflective spectroscopy. Single locus analyses failed to demonstrate an association between any of the 5 SNPs and skin pigmentation. However, when an epistatic model was applied to the data, a significant gene-gene interaction was identified between Val92Met in MCIR and IVS13-15 in the P gene (F=2.43; P=0.0105). We also discuss the possible mechanisms of how gene interactions arise in signal transduction pathways.

Adolescent↗
PubMed2001

Regulation of intestinal apolipoprotein A-I synthesis by dietary phosphatidylcholine in newborn swine.

Phospholipid (PL) from both dietary sources and biliary secretions may be important in the regulation of intestinal apolipoprotein (apo) synthesis. We previously demonstrated the up-regulation of apo A-I secretion by phosphatidylcholine (PC) in a newborn piglet intestinal epithelial cell line. We hypothesized that dietary PC increases small intestinal apo A-I synthesis in vivo in the newborn piglet. Two-day-old female swine were fed by gavage for 48 h. Diets consisted of a formula containing 51% of calories as triacylglycerol providing 180 kcal/kg/24 h. The experimental group (+PC, n = 7) received 1 g/L added soybean PC, and the control group (-PC, n = 7) received no added PC. At the end of the study period, jejunal apo A-I, B, and A-IV synthesis was measured, and apo A-I mRNA levels were quantitated. Jejunal mucosal PL content and serum lipids and apo B and A-I levels were measured. Jejunal apo A-I synthesis was almost twice as high in the +PC group as compared to the -PC group with no difference in apo A-I mRNA levels. Jejunal content of PL was higher in the +PC group than in the -PC group. There were no differences in jejunal apo B and A-IV synthesis or serum levels of lipids and apo-lipoproteins between the two groups. Dietary PC supplementation in newborn swine up-regulated jejunal apo A-I synthesis. Apo A-IV synthesis, which is sensitive to fatty acid flux, was not significantly increased, which suggests a specific effect of PC on apo A-I synthesis. Lumenal PC may be important in the regulation of intestinal apo A-I synthesis in the neonate.

Animals↗
PubMed2001

Ganglioside GM2/GD2 synthetase mRNA is a marker for detection of infrequent neuroblastoma cells in bone marrow.

GalNAcbeta1-4(NeuAcalpha2-3)Galbeta1-4Glcbeta1-Cer (GM2)/GalNAcbeta1-4(NeuAcalpha2-8NeuAcalpha2-3)Galbeta1-4Glcbeta1-1Cer (GD2) synthetase [beta-1,4-N-acetyl-galactosaminyl transferase (GalNAc-T)] mRNA, which encodes a key glycosyltransferase for ganglioside GD2 synthesis, was assessed as a molecular marker for detecting metastatic neuroblastoma cells in bone marrow (BM). GalNAc-T mRNA expression by neuroblastoma cell lines (n = 15), primary untreated neuroblastoma tumors (n = 29), morphologically normal BM (n = 22), peripheral blood stem cells (n = 10) from patients with cancers other than neuroblastoma, and blood mononuclear cells from normal donors (n = 17) was assessed by using reverse transcriptase-polymerase chain reaction (RT-PCR) and electrochemiluminescence detection assay (RT-PCR/ECL). BM harvested from 15 neuroblastoma patients was tested before and after ex vivo immunomagnetic bead purging, and results were compared to immunocytological analysis of the same specimens. All neuroblastoma cell lines (mean, 653 x 10(3) ECL units) and primary tumors (mean, 683 x 10(3) ECL units) were positive for significant expression of GalNAc-T mRNA compared to normal blood and BM cells. The RT-PCR/ECL assay could detect GalNAc-T mRNA in 100 pg of total RNA, and in a mixture of one neuroblastoma cell among 10(7) normal BM or blood cells. Eight of 15 autologous BM cells harvested from patients with neuroblastoma had tumor cells detectable by immunocytology, and all 15 were positive for GalNAc-T mRNA. After ex vivo purging, none of the BM cells was immunocytology-positive, but six remained positive by the RT-PCR/ECL assay. GalNAc-T mRNA provides a specific and sensitive molecular marker for RT-PCR/ECL detection of infrequent neuroblastoma cells in BM.

Adolescent↗
PubMed2001

Differential effects of enrichment on learning and memory function in NR2B transgenic mice.

It has been known that environmental enrichment leads to better learning and memory in mice. However, the molecular mechanisms are not known. In this study, we used the 10th-12th of the NR2B transgenic (Tg) lines, in which the NMDA receptor function is enhanced via the NR2B subunit transgene in neurons of the forebrain, to test the hypothesis of the involvement of NMDA receptor function in enrichment-induced better learning and memory. Consistent with our previous results, both larger long-term potentiation (LTP) in the hippocampus and superior learning and memory were observed in naive NR2B Tg mice even after the 10th-12th generation of breeding. After enrichment, wild-type mice exhibited overall improvement in their performances in contextual and cued conditioning, fear extinctions, and novel object recognition tasks. Interestingly, the same enrichment procedures could not further increase the performance of NR2B Tg mice in contextual conditioning, cued conditioning, or fear extinction, thereby indicating that enhanced NMDA receptor function can occlude these enrichment effects. However, we found that in the novel object recognition task enriched NR2B Tg mice exhibited much longer recognition memory (up to 1 week), compared to that (up to 3 days) in naive NR2B Tg mice. Furthermore, our biochemical experiments showed that enrichment significantly increased protein levels of GluR1, NR2B, and NR2A subunits of glutamate receptors in both wild-type and NR2B Tg mice. Therefore, our results suggest an interactive nature of molecular pathways involved in both environmental and genetic NMDA receptor manipulations for enhancing learning and memory.

Animals↗
PubMed2001

NMR studies of molecular structure in fruit cuticle polyesters.

The cuticle of higher plants functions primarily as a protective barrier for the leaves and fruits, controlling microbial attack as well as the diffusion of water and chemicals from the outside environment. Its major chemical constituents are waxes (for waterproofing) and cutin (a structural support polymer). However, the insolubility of cutin has hampered investigations of its covalent structure and domain architecture, which are viewed as essential for the design of crop protection strategies and the development of improved synthetic waterproofing materials. Recently developed strategies designed to meet these investigative challenges include partial depolymerization using enzymatic or chemical reagents and spectroscopic examination of the intact polyesters in a solvent-swelled form. The soluble oligomers from degradative treatments of lime fruit cutin are composed primarily of the expected 10,16-dihydroxyhexadecanoic and 16-hydroxy-10-oxo-hexadecanoic acids; low-temperature HF treatments also reveal sugar units that are covalently attached to the hydroxyfatty acids. Parallel investigations of solvent-swollen cutin using 2D NMR spectroscopy assisted by magic-angle spinning yield well-resolved spectra that permit detailed comparisons to be made among chemical moieties present in the intact biopolymer, the soluble degradation products, and the unreacted solid residue.

Citrus↗
PubMed2001

The role of genetic abnormalities of PTEN and the phosphatidylinositol 3-kinase pathway in breast and ovarian tumorigenesis, prognosis, and therapy.

Breast and ovarian cancers exhibit similar epidemiologic, genotypic, and phenotypic characteristics. Phosphatidylinositol 3-kinase (PI3K) and the PTEN tumor suppressor gene product phosphorylate and dephosphorylate the same 3' site in the inositol ring of membrane phosphatidylinositols. Germ-line mutations in the PTEN tumor suppressor gene are causative of Cowden's breast cancer predisposition syndrome, and PTEN is frequently mutated in sporadic breast cancers. In contrast, amplification of multiple components of the PI3K pathway is a hallmark of serous epithelial ovarian cancers. The resultant activation of the PI3K pathway in both breast and ovarian cancers contributes to cell-cycle progression, decreased apoptosis, and increased metastatic capabilities. Strikingly, both ovarian and breast cancer cells are selectively sensitive to pharmacologic and genetic manipulation of the PI3K pathway, making molecular therapeutics targeting this pathway particularly attractive approaches for these cancers.

Animals↗
PubMed2001

A preliminary in vitro study on the fabrication and tissue engineering applications of a novel chitosan bilayer material as a scaffold of human neofetal dermal fibroblasts.

The bilayer structure of chitosan film and sponge was designed as a scaffold of skin tissue engineering and a dermis substitute. It was processed successively via the formation of a dense chitosan film by casting method and a porous chitosan sponge by lyophilization. The dry thickness of the film layer was 19.6 microm and that of the sponge layer was controlled at 60-80 microm. Porogens such as sodium chloride, glucose, and sucrose were used to create large pores of the chitosan sponge layer. Human neofetal dermal fibroblasts were seeded in the chitosan sponge layer and cultured for 4 weeks. It was found that the cells could grow and proliferate well in an extended shape on the flat bottom of large pores with 15-100 microm width and in spherical form on the rough pore walls or at the edges of micropores less than 5 microm. Fibroblasts after the culture could bind tightly with the sponge layer via newly formed extracellular matrices to give a living cell-matrix-chitosan composite. The bilayer chitosan material remained stable in shape and size during the cell culture. The results suggested that the bilayer chitosan material would be an alternative of collagen materials which was obviously contracted during cell culture.

Biocompatible Materials↗
PubMed2001

Nucleotide sequence and deduced amino acid sequence of the medium RNA segment of Oropouche, a Simbu serogroup virus: comparison with the middle RNA of Bunyamwera and California serogroup viruses.

The Bunyavirus genus of the family Bunyaviridae contains 18 serogroups. To date nucleotide sequence data has been obtained for three serogroups, Bunyamwera, California and Simbu, based on analysis of the small (S) RNA segment. In comparison, there is only nucleotide sequence data for the large and medium (M) RNA segments for members of the Bunyamwera and California serogroups. In this paper we report the nucleotide sequence of the M RNA of Oropouche (ORO) virus, a member of the Simbu serogroup. The M RNA was 4396 nucleotides in length with G1, G2 and NSm proteins similar in size to those reported for members of the Bunyamwera and California serogroups. However, there was limited nucleotide (50-52%) and amino acid (30-32%) homology between ORO virus M RNA and those of published members of the other two serogroups. The Bunyamwera and California serogroups are more closely related to each other than the Simbu serogroup virus Oropouche. These data were consistent with that previously reported for the S RNA (Saeed et al., 2000. J. Gen. Virol. 81, 743-748). It has been noted previously that three of four potential N-linked glycosylation sites of the Bunayamwera and California serogroups are conserved in G1 and G2 proteins. In contrast, ORO virus was found to have only three potential N-linked glycosylation sites of which only one, in G1, was conserved with members of the other two serogroups. Comparison of M RNA sequences of different strains of ORO virus revealed genetic variation consistent with that reported previously for the S RNA.

Amino Acid Sequence↗
PubMed2001

Jatobal virus is a reassortant containing the small RNA of Oropouche virus.

Jatobal (JAT) virus was isolated in 1985 from a carnivore (Nasua nasua) in Tucuruí, Pará state, Brazil and was classified as a distinct member of the Simbu serogroup of the Bunyavirus genus, family Bunyaviridae on the basis of neutralization tests. On the basis of nucleotide sequencing, we have found that the small (S) RNA of JAT virus is very similar (>95% identity) to that of Oropouche (ORO) virus, in particular, the Peruvian genotype of ORO virus. In comparison, limited nucleotide sequencing of the G2 protein gene, encoded by the middle (M) RNA, of JAT and ORO viruses, revealed relatively little identity (<66%) between these two viruses. Neutralization tests confirmed the lack of cross-reactivity between the viruses. These results suggest that JAT virus is a reassortant containing the S RNA of ORO virus. JAT virus was attenuated in hamsters compared to ORO virus suggesting that the S RNA of ORO virus is not directly involved in hamster virulence.

Amino Acid Sequence↗