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Biomedical subjects

Y Zhuang

Publications and source records attributed to Y Zhuang.

At least 19 recordsLinked to original sources
PubMed2001

The development of iodine based impinger solutions for the efficient capture of Hg0 using direct injection nebulization-inductively coupled plasma mass spectrometry analysis.

Inductively coupled plasma mass spectrometry (ICP/MS) with direct injection nebulization (DIN) was used to evaluate novel impinger solution compositions capable of capturing elemental mercury (Hg0) in EPA Method 5 type sampling. An iodine based impinger solution proved to be very efficient for Hg0 capture and was amenable to direct analysis by DIN-ICP/MS. Hg0 capture efficiency using aqueous iodine (I3-) was comparable to Hg0 capture using acidified potassium permanganate impinger solutions which were analyzed by cold vapor atomic absorption spectrometry (CVAAS), with greater than 98% capture of Hg0 in the first oxidizing impinger. Using DIN-ICP/MS, it was demonstrated for the first time that iodine can be generated just prior to impinger sampling for efficiently oxidizing Hg0 and retaining it in solution as HgI4(2-). Due to the increased interest in Hg speciation from combustion sources and the potential for using DIN-ICP/MS for multiple metals analyses, an impinger sampling train for gaseous Hg speciation and multiple metals analyses using DIN-ICP/MS analyses is presented. The unique feature of such a sampling train is that each impinger solution in the series is amenable to direct analysis by DIN-ICP/MS. A bituminous coal was combusted in a bench scale coal system, and gaseous Hg species (oxidized and elemental) were determined using the proposed impinger train. The DIN-ICP/MS instrumental detection limit was 0.003 ppb, and MDLs ranged from 0.007 to 0.116 microg/L (ppb) in a variety of impinger solutions used for Hg capture.

Air Pollutants↗
PubMed2001

Serum cholesteryl ester transfer protein concentrations in healthy Chinese subjects and cardio-cerebrovascular disease patients.

Serum cholesteryl ester transfer protein (CETP) concentration was measured in 1128 healthy Chinese subjects using a "sandwich" enzyme immunoassay and was 1.84 +/- 1.55 mg/l (mean +/- S.D.). The frequency distribution of CETP in healthy subjects was markedly skewed towards low concentrations. The CETP concentration in females was significantly higher than that in males (2.40 +/- 1.65 mg/l vs. 1.49 +/- 1.37 mg/l, P < 0.001). There was a weak inverse correlation between the CETP concentration and age (r = -0.19, P < 0.001). The CETP concentrations were significantly higher in 117 myocardial infarction (MI) survivors and 110 stroke patients than that in 335 healthy, age-matched males (1.98 +/- 1.68 173 +/- 1.45, and 1.40 +/- 1.37 mg/l respectively, P < 0.01), while no relation was found between CETP concentration and lipids concentration in MI, stroke and healthy group.

Cardiovascular Diseases↗
PubMed2001

Relationship between endogenous estrogen concentrations and serum cholesteryl ester transfer protein concentrations in Chinese women.

BACKGROUND: CETP plays an important role in HDL metabolism and in the reverse cholesterol transport pathway. METHODS: The relationship between the changes of endogenous estrogen and the concentration of cholesteryl ester transfer protein (CETP) in the serum of Chinese women was investigated. Serum concentrations of estradiol (E(2)), follicle-stimulating hormone (FSH), CETP and lipid profile were determined in 196 Chinese women (52 premenopausal with ages ranging from 18 to 40 years, 57 perimenopausal from 41 to 60 years, and 87 postmenopausal from 61 to 81 years). RESULTS: Serum CETP concentration was significantly lower in postmenopausal women compared with those in perimenopausal and premenopausal women (1.39+/-1.06, 2.36+/-1.50 and 2.31+/-1.25 mg/l, respectively, P<0.0001). Even in the women around the menopausal, CETP concentration in postmenopause was significantly lower than that in premenopause (1.93+/-1.33 vs. 3.42+/-1.35 mg/l, P<0.01). In addition, CETP concentration had a highly positive correlation with serum concentration of E(2) (r=0.243, P<0.001), while negative correlation of CETP concentration with serum concentration of FSH was found (r=-0.273, P<0.001). CONCLUSIONS: Estrogen may affect the concentration of CETP.

Adolescent↗
PubMed2001

Inhibitory effects of rosa roxburghii tratt juice on in vitro oxidative modification of low density lipoprotein and on the macrophage growth and cellular cholesteryl ester accumulation induced by oxidized low density lipoprotein.

BACKGROUND: Rosa roxburghii tratt juice (RRTJ) administration has been shown to significantly ameliorate atherosclerotic diseases in cholesterol-fed animals. However, the mechanism for the antiatherogenic effect of RRTJ is not clear. METHODS: We investigated the effects of RRTJ on in vitro oxidative modification of LDL and on LDL-induced macrophage growth and cellular cholesteryl ester (CE) accumulation. The effects of RRTJ on LDL oxidative modification were assessed by relative electrophoretic migration, thiobarbituric acid-reactive substance (TBARS) content, and the formation of conjugated dienes. The inhibition of RRTJ on oxidized LDL (Ox-LDL)-induced murine peritoneal macrophage growth was evaluated by a cell-counting assay and an MTT assay. The effect of RRTJ on Ox-LDL-induced cellular CE accumulation was examined after macrophages were incubated with Ox-LDL in the presence of RRTJ. To clarify the mechanism of the inhibitory effect of RRTJ on Ox-LDL-induced CE accumulation in macrophages, its capacity for cholesterol efflux from macrophage-derived foam cells were examined. RESULTS: We showed that RRTJ significantly reduced LDL oxidative susceptibility. In addition, RRTJ effectively suppressed Ox-LDL-induced macrophage growth and especially Ox-LDL-induced CE accumulation in murine peritoneal macrophages by promoting cellular cholesterol efflux. CONCLUSION: These results indicated that RRTJ exerted its antiatherogenic effects largely due to its ability to inhibit the oxidative modification of LDL and to suppress the formation of foam cells.

Animals↗
PubMed2001

[Adsorption of anthraquinone dyes by biosorbent GX2].

The GX2 growing mycelium shows excellent adsorptive capacity on the four kinds of anthraquinone dyes, however, due to the difference of molecular structure of dyes, the adsorption rates are different. Although the dyes show inhibiting effect on the growth of GX2, when the concentration of reactive brilliant blue KN-R is 250 and 400 mg/L, the adsorption rate of dye by the GX2 growing mycelium reaches 100% and 91.4%, respectively. With the increase of salinity (NaCl), the dry weight of GX2 mycelium increases; the diameter of granular mycelium decreases and its adsorption surface area increases accordingly, the salinity shows evident enhancement on the adsorption of reactive brilliant blue KN-R by GX2 growing mycelium in the range of 0%-2% salinity. The adsorption process is influenced by the concentration of carbon source as well, reactive brilliant blue KN-R with the concentration of 120 mg/L can be completely adsorbed only when the concentration of glucose is more than 2.5 g/L. The GX2 growing mycelium has better adsorptive capacity than resting living mycelium and dead mycelium.

Adsorption↗
PubMed2001

[Clinical analysis of tubulointerstitial lesions in IgA nephropathy].

OBJECTIVE: To analyze the characteristics of tubulointerstitial lesions (TIL) in IgA nephropathy (IgAN). METHODS: The pathologic and clinical materials of 609 IgAN patients were analyzed. RESULTS: (1) Prevalence characteristics of TIL: Among all the patients, these with mild TIL accounted for 47.1%, moderate TIL 21.7%, severe TIL was about 16.6% and these without TIL 14.6%. (2) Relationship between TIL and the clinical findings: With increase of the severity of TIL, hypertension became worse and the level of proteinuria increased gradually. On the contrary, serum albumin decreased and renal function degraded. (3) Relationship between TIL and the pathologic findings: With increase of the severity of TIL, the scores of vascular lesion, total glomerular lesion, hypercellularity and glomerulosclerosis increased gradually. Moreover, when the glomerular lesion and vascular lesion became worse, the severity of TIL also increased. The relationship with the crescents was different, the score of the presence of crescents was highest when TIL was moderate in severity; it would not increase when TIL was severe. CONCLUSION: With the increase of the severity of TIL, the condition of IgAN patients became worse. TIL may be one of the key factors for the prognosis of IgAN. TIL is closely related to the severity of glomerular and vascular lesions, and these lesions may further lead to the development of TIL.

Adolescent↗
PubMed2001

[Sulfa-drug wastewater treatment with anaerobic/aerobic process].

Sulfa drug wastewater was treated with anaerobic/aerobic process. The removal ratios of TOC reached about 50% in anaerobic phase and about 70% in aerobic phase respectively, while volume loading rate of TOC was about 1.2 kg/(m3.d) in anaerobic phase and about 0.6 kg/(m3.d) in aerobic phase. Removal of TOC in anaerobic phase was attributed to the reduction of sulfate.

Aerobiosis↗
PubMed2001

[Relationship of abnormal umbilical artery flow velocity waveforms and placental pathology].

OBJECTIVE: To investigate the relationship of abnormal umbilical artery (UmA) flow velocity waveforms (FVWS) with placental weight, volume and all classes of villi and vessels. METHODS: Ten IUGR with abnormal umbilical artery(AA) were set as pathological group. Ten normal weight births with abnormal UmA FVWS(AN), 10 IUGR with normal UmA FVWS (NA), 10 normal weight births with normal UmA FVWS (NN) were selected as controls. Anti-alpha-SMA antibody was used to examine placental stem vessels and stem villi. The placental weight, volume, numbers of all classes of villi and vessels were compared. RESULTS: (1) Placental weight and volume in pathological group reduced significantly, while compared with AN (P < 0.01, P < 0.05, respectively), NA (P < 0.01, P < 0.001, respectively), and NN (all the P values < 0.001). (2) When the pathological group was compared with other 3 control groups with respect to the numbers of all classes of villi and vessels in placenta, the number of stem vessels reduced significantly (P < 0.05, P < 0.01, P < 0.001 respectively). The number of stem villi reduced significantly, compared with NA and NN (P < 0.01, P < 0.001, respectively). The number of stem villi did not change when compared with AN (P > 0.05). CONCLUSION: Abnormal UmA FVWS is related with placental weight, volume, all classes of villi and vessels. The reduction of villous and vascular number may be due to arrest of placental angiogenesis but not selective obliteration of vessels.

Actins↗
PubMed2001

[Studies on characteristics of kinetics and metabolic shift of genetically engineered yeast Pichia pastoris in high-density chemostat cultivation].

Kinetics and metabolic shift of DNA recombinant yeast Pichia pastoris was studied in high-density chemostat cultivation in which the glycerol was used as a limited substrate. The experimental results showed that (1) cell optical density (OD600) of Pichia pastoris was linear with its dry cell weight (DCW) and wet cell weight (WCW), and reached 100 OD600 = 128.3 g WCW/L or 100 OD600 = 22.9 g DCW/L; (2) The relationship of specific growth rate (mu) and residual concentration of glycerol is accorded with Monod Equation, to obtain mu = mumax S/(Ks + S), where mumax = 0.366 h-1, Ks = 0.1823 g/L. The maximum cell yield of glycerol substrate YG = 0.54 g/g, growth maintaining coefficient m = 0.0069 g/(g.h), The cell yield of oxygen YX/O2 = 30.96 g/moL, and the optimum theoretical dilution rate Dm = 0.341 h-1 by parameter inference; (3) With specific growth rate (mu) increasing, glycerol metablic flux shifts linearly from glycogenesis and hexosephosphate pathways to glycolysis and tricarboxylic acid cycle pathways on basis of variations of consumption rate of NH3.H2O and respiratory quotient value.

Biotechnology↗
PubMed2000

Up-regulation of Na,K-ATPase beta 1 transcription by hyperoxia is mediated by SP1/SP3 binding.

The sodium pump, Na,K-ATPase, is an important protein for maintaining intracellular ion concentration, cellular volume, and ion transport and is regulated both transcriptionally and post-transcriptionally. We previously demonstrated that hyperoxia increased Na,K-ATPase beta(1) gene expression in Madin-Darby canine kidney (MDCK) cells. In this study, we identify a DNA element necessary for up-regulation of the Na,K-ATPase beta(1) transcription by hyperoxia and evaluate the nuclear proteins responsible for this up-regulation. Transient transfection experiments in MDCK cells using sequential 5'-deletions of the rat Na,K-ATPase beta(1) promoter-luciferase fusion gene demonstrated promoter activation by hyperoxia between -102 and +151. The hyperoxia response was localized to a 7-base pair region between -62 and -55, which contained a GC-rich region consistent with a consensus sequence for the SP1 family, that was sufficient for up-regulation by hyperoxia. This GC element exhibited both basal and hyperoxia-induced promoter activity and bound both transcription factors SP1 and SP3 in electrophoretic mobility shift assays. In addition, electrophoretic mobility shift assays demonstrated increased binding of SP1/SP3 in cells exposed to hyperoxia while mutation of this element eliminated protein binding. Other GC sites within the proximal promoter also demonstrated up-regulation of transcription by hyperoxia, however, the site at -55 had higher affinity for SP proteins.

Animals↗
PubMed2000

Regulation of Na,K-ATPase beta 1 subunit gene transcription by low external potassium in cardiac myocytes. Role of Sp1 AND Sp3.

Expression of Na,K-ATPase activity is up-regulated in cells incubated for extended intervals in the presence of low external K(+). Our previous data showed that exposure of cardiac myocytes to low K(+) increased the steady-state abundance of Na,K-ATPase beta1 subunit mRNA. In the present study we determined that incubation of primary cultures of neonatal rat cardiac myocytes with low K(+) augmented Na,K-ATPase beta1 gene expression at a transcriptional level and that this effect required extracellular Ca(2+). The stimulatory effect of low K(+) on Na,K-ATPase beta1 gene transcription was not dependent on increased contractile activity of cardiac myocytes. Na,K-ATPase beta1 5'-flanking region deletion plasmids used in transient transfection analysis demonstrated that the region between nucleotides -62 to -42 of the beta1 promoter contained a low K(+) response element. Site-directed mutagenesis of a potential GC box core motif GCG in the -58/-56 region of the beta1 promoter decreased basal and low K(+)-mediated transcription. Mutation of the core sequence of a putative GC box element located between nucleotides -101 and -99 further decreased the low K(+) effect on beta1 gene transcription. Electrophoretic mobility shift assays using oligonucleotides spanning the proximal and distal GC box elements of the beta1 promoter showed enhanced binding of two complexes in response to low K(+). The inclusion of a consensus GC box sequence as a competitor in gel shift analysis reduced factor binding to the low K(+) response elements. Antibodies to transcription factors Sp1 and Sp3 interacted with components of both DNA-binding complexes and binding of nuclear factors was abolished in gel shift studies using GC box mutants. Together these data indicate that enhanced binding of Sp1 and Sp3 to two GC box elements in the rat Na,K-ATPase beta1 subunit gene promoter mediates beta1 gene transcription up-regulation in neonatal rat cardiac myocytes exposed to low external K(+).

Animals↗
PubMed2000

Novel imidazolyl and triazolyl substituted biphenyl compounds: synthesis and evaluation as nonsteroidal inhibitors of human 17alpha-hydroxylase-C17, 20-lyase (P450 17).

The synthesis of a new series of P450 17 inhibitors is described. The imidazol-1-yl compounds 5 showed strong inhibition of P450 17 rat and especially human enzyme, the most active compounds being 5ax, 5ay and 5bx with IC50 values of 0.17, 0.24 and 0.25 microM, respectively (ketoconazole: 0.74 microM). The 1,2,4-triazol-1-yl compounds 6 were less active, while the 1,2,4-triazol-4-yl compounds 7 were inactive. The title compounds showed little inhibition of P450 arom. The most active P450 17 inhibitors 5ax and 5ay markedly decreased the testosterone plasma concentration of SD rats 2 h after application of 0.019 mmol/kg. After 6 h, 5ay still exhibited a strong effect.

Animals↗
PubMed2000

Mekk3 is essential for early embryonic cardiovascular development.

The early development of blood vessels consists of two phases, vasculogenesis and angiogenesis, which involve distinct and also overlapping molecular regulators, but the intracellular signal transduction pathways involved in these processes have not been well defined. We disrupted Map3k3 (also known as Mekk3), which encodes Mekk3, a member of the Mekk/Ste11 family, in mice. Map3k3-/- embryos died at approximately embryonic day (E) 11, displaying disruption of blood vessel development and the structural integrity of the yolk sac. Angiogenesis was blocked at approximately E9.5 in mutant embryos. Map3k3 disruption did not alter the expression of the genes encoding Vegf-1, angiopoietin or their receptors. The development of embryonic, but not maternal, blood vessels in the placentas of Map3k3-/- embryos was impaired, revealing an intrinsic defect in Map3k3-/- endothelial cells. Moreover, Mekk3 activated myocyte-specific enhancer factor 2C (Mef2c), a transcription factor crucial for early embryonic cardiovascular development through the p38 mitogen-activated protein kinase (Mapk) cascade. We conclude that Mekk3 is necessary for blood vessel development and may be a possible target for drugs that control angiogenesis.

Animals↗
PubMed2000

Functions of E2A-HEB heterodimers in T-cell development revealed by a dominant negative mutation of HEB.

Lymphocyte development and differentiation are regulated by the basic helix-loop-helix (bHLH) transcription factors encoded by the E2A and HEB genes. These bHLH proteins bind to E-box enhancers in the form of homodimers or heterodimers and, consequently, activate transcription of the target genes. E2A homodimers are the predominant bHLH proteins present in B-lineage cells and are shown genetically to play critical roles in B-cell development. E2A-HEB heterodimers, the major bHLH dimers found in thymocyte extracts, are thought to play a similar role in T-cell development. However, disruption of either the E2A or HEB gene led to only partial blocks in T-cell development. The exact role of E2A-HEB heterodimers and possibly the E2A and HEB homodimers in T-cell development cannot be distinguished in simple disruption analysis due to a functional compensation from the residual bHLH homodimers. To further define the function of E2A-HEB heterodimers, we generated and analyzed a dominant negative allele of HEB, which produces a physiological amount of HEB proteins capable of forming nonfunctional heterodimers with E2A proteins. Mice carrying this mutation show a stronger and earlier block in T-cell development than HEB complete knockout mice. The developmental block is specific to the alpha/beta T-cell lineage at a stage before the completion of V(D)J recombination at the TCRbeta gene locus. This defect is intrinsic to the T-cell lineage and cannot be rescued by expression of a functional T-cell receptor transgene. These results indicate that E2A-HEB heterodimers play obligatory roles both before and after TCRbeta gene rearrangement during the alpha/beta lineage T-cell development.

Alleles↗
PubMed2000

A genetic investigation of E2A function in lymphocyte development.

Lymphocytes are derived from hematopoietic stem cells (HSC) following a series of regulated differentiation events. Multipotent HSCs become committed to the B cell lineage in bone marrow and the T cell lineage in the thymus after receiving appropriate signals from the corresponding microenvironment. These committed lymphoid cells must then undergo V(D)J recombination at the immunoglobulin gene or T cell receptor gene locus resulting in clonal production of functional B or T lymphocytes, respectively. Lymphocyte commitment and differentiation are accompanied by programmed gene expression or repression events which are driven by lineage and stage specific transcription factors. The basic-helix-loop-helix (bHLH) transcription factors encoded by the E2A gene are involved in several differentiation events during B and T cell development, including lineage commitment, initiation of V(D)J recombination, and antigen receptor mediated proliferation and differentiation. Several recent reviews have provided a comprehensive discussion of biochemical, cellular, and genetic research on E2A function in lymphocyte development (1,2). Here, we only discuss some of the genetic approaches our laboratory (except where it is noted) has undertaken to investigate the molecular pathways mediated by E2A transcription factors in lymphocyte development.

Animals↗
PubMed2000

[Vascular endothelial growth factor expression in placenta from intrauterine growth retardation fetus with abnormal umbilical artery flow velocity waveforms].

OBJECTIVE: To study the relationship between placental vascular endothelial growth factor (VEGF) expression and intrauterine growth retardation (IUGR) with abnormal Umbilical artery flow velocity waveforms (UmA FVWS), and deduce the oxygen content in placental terminal villi. METHODS: The VEGF expression levels in syncytiotrophoblast and stroma cells were determined by sp immunohistochemistry, and were compared between the following 4 groups: abnormal UmA FVWS and IUGR (AVAW), abnormal UmA FVWS and normal birth-weight (AVNW), normal UmA FVWS and IUGR (NVAW), normal UmA FVWS and normal birth-weight (NVNW). Each group included 10 cases. RESULTS: In all the placentae, VEGF was mainly expressed in syncytiotrophoblasts with less immunostaining in stroma cells. The intensity of VEGF immunostaining in stroma cells was similar in the groups studied so far. The VEGF expression in syncytiotrophoblasts was significantly reduced in group AVAW (VEGF positive rate in syncytiotrophoblasts is 13.0%), compared with NVAW (VEGF positive rate in syncytiotrophoblasts is 38.50%; P < 0.01) and NVNW (VEGF positive rate in syncytiotrophoblasts is 39.6%; P < 0.01). There was a negative linear correlation between VEGF positive rate in syncytiotrophoblasts and the values of UmA PI (r = -0.52, P < 0.001), RI (r = -0.43, P < 0.01), S/D (r = -0.40, P < 0.01). CONCLUSIONS: The reduction of VEGF expression levels in syncytiotrophoblasts correlates with abnormal UmA FVWS and IUGR. The reduced expression of VEGF in syncycciotrophoblasts may be responsible for the impaired development of all classes of vessels and villi of the placentas from IUGR with abnormal UmA FVWS. The oxygen content is increased within terminal villi of IUGR with abnormal UmA FVWS.

Adult↗
PubMed2000

[The immunogenic characteristics of the recombinant 38,000 antigen from Mycobacterium tuberculosis].

OBJECTIVE: To study the ability of recombinant 38,000 protein of Mycobacterium tuberculosis (rMT38) to induce antibodies and its value as a serological diagnostic reagent. METHODS: Rabbits were divided into six groups, namely: PPD + physiological saline(group A), rMT38 + physiological saline(group B), rMT38 + adjuvent(group C), 1/2 rMT38 + 1/2 rMT16 + physiological saline(group D), 1/2 rMT38 + 1/2 rMT16 + adjuvent(group E), rMT16 + adjuvent(group F). The sera from the immunized rabbits and the sera immunized by mycobacteria were evaluated by enzyme-linked immunosorbent assay(ELISA) and bilateral agar diffusion assay (BADA). 389 human sera, including 145 patients with pulmonary tuberculosis, 105 healthy controls, 31 non-tuberculosis respiratory patients, 78 BCG-vaccinated healthy controls and 30 patients with M. abscessus infection, were detected by ELISA. RESULTS: Titers of specific antibodies in sera from C and E groups were 1:16 and 1:4 in BADA, and 1:6,400 and 1:3,200 in ELISA, respectively. Precipitate lines of sera from A, B, D, F groups reacting with rMT38 were not found by BADA. Sera titer of A, B, D, F groups were negative, 1:400, 1:400, and negative by ELISA, respectively. Sera from E group had no reaction with PPD from thirteen mycobacteria, however, sera from E group reacted with PPD from Mycobacterium tuberculosis and BCG. Sera titer of all rabbits decreased with time. After two months, serum titers in B and D groups became negative. However, antibodies were still found in C and E groups after five months. The sensitivity of rMT38 and PPD in detecting pulmonary tuberculosis were 69.0% and 75.2%, respectively. The specificity of rMT38 and PPD in detecting healthy controls, non-tuberculosis respiratory patients, BCG-vaccinated healthy controls and M. abscessus-infected patients were 97.1%, 93.5%, 86.0%, 53.6% and 94.3%, 87.1%, 67.9%, 39.3% respectively. CONCLUSION: rMT38 has a strong immunogenicity, which may be used as an immunodiagnostic reagent for tuberculosis.

Animals↗