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S Wu

Publications and source records attributed to S Wu.

At least 253 records · Page 14Linked to original sources
PubMed1998

Cloning and nucleotide sequence of amidase gene from Pseudomonas putida.

Amidases are a class of enzymes which convert amides to acids and have potential value in the development of commercial bioprocesses for the production of useful chemicals. A gene encoding an amidase in Pseudomonas putida 5B has been cloned, sequenced, and overexpressed in Escherichia coli. An additional open reading frame (P38K) encoding a putative protein of 38 kDa was found immediately upstream of the amidase gene. This work continues our characterization of a P. putida operon, which now appears to include P38K, amidase, and a stereo-specific nitrile hydratase. This characterization underlies continuing efforts in biocatalyst development.

Amidohydrolases↗
PubMed1998

Reactive oxygen species in reoxygenation injury of rat brain capillary endothelial cells.

OBJECTIVE: To clarify the mechanism of anoxia/reoxygenation (A/R) injury of rat brain capillary endothelial cells (BCEC). METHODS: BCEC isolated from Sprague-Dawley rats by enzymatic treatment and centrifugation were subjected to anoxia (95% N2, 5% CO2) for 20 minutes and then to reoxygenation (95% air, 5% CO2) for 3 hours. Enzyme inhibitors, including oxypurinol, indomethacin, and N(G)-nitro-L-arginine methyl ester, or specific free-radical scavengers, such as superoxide dismutase, catalase, and the ferric iron chelator deferoxamine, were added before A/R injury. The BCEC were incubated in a range of Ca2+ concentrations from 1 to 0.01 mmol/L during A/R injury. Cytotoxicity was assayed by release of intracellular lactate dehydrogenase (LDH). RESULTS: With A/R injury, LDH release from the control group (no protective agents) significantly increased (44.8 +/- 3.3%), compared with a small increase in a normoxic group. BCEC treated with oxypurinol, indomethacin, or N(G)-nitro-L-arginine methyl ester showed suppression of LDH release. LDH release was almost totally suppressed by superoxide dismutase and partially by catalase or deferoxamine. The LDH release was partly dependent on calcium concentration. CONCLUSION: BCEC subjected to A/R become potent generators of free radicals, especially superoxide anion. Free radical production depends on both xanthine oxidase and cyclooxygenase pathways. Peroxynitrite and extracellular Ca2+ both contribute importantly to reoxygenation injury of BCEC.

Animals↗
PubMed1998

Genetic organization of the mecA region in methicillin-susceptible and methicillin-resistant strains of Staphylococcus sciuri.

A homolog of the Staphylococcus aureus methicillin resistance gene mecA was recently shown to be ubiquitous in independent isolates of the animal species Staphylococcus sciuri. The mecA gene homolog and regions flanking it were cloned and sequenced from four strains of S. sciuri: strain K1 (ATCC 29062), a representative of S. sciuri subsp. sciuri; two strains (K3 and K8) representing S. sciuri subsp. rodentius; and strain K11, a representative of S. sciuri subsp. carnaticum. Strains K1 and K11 were susceptible to methicillin, while strains K3 and K8 showed heterogeneous resistance. The mecA genes of strains K1 and K11 and one of the two copies of mecA (mecA1) present in strain K3 had virtually identical DNA sequences in the mecA gene and were similar in genetic organization in the flanking regions. In contrast, the single copy of mecA in strain K8 and the second copy of mecA (mecA2) in strain K3 had mecA DNA sequences identical to that of S. aureus mecA, and the mecA region in these two strains was also similar to that of the same region in the S. aureus strain used for comparison. Interestingly, an open reading frame defining an N-terminal truncated polypeptide, NTORF101, with a high degree of homology to a DNA segment in the hypervariable region of methicillin-resistant S. aureus (and also similar to the Escherichia coli gene ugpQ) was also identified downstream of the mecA homolog of strain K11, representing S. sciuri subsp. carnaticum. The ugpQ-like gene is not present in methicillin-susceptible strains of S. aureus. The presence of such a ugpQ-like gene together with the homolog of mecA in strain K11 supports the speculation that these genetic elements may be evolutionary relatives and/or precursors of the genetic determinant of methicillin resistance in S. aureus.

Amino Acid Sequence↗
PubMed1998

Chemokine coreceptor usage by diverse primary isolates of human immunodeficiency virus type 1.

We tested chemokine receptor subset usage by diverse, well-characterized primary viruses isolated from peripheral blood by monitoring viral replication with CCR1, CCR2b, CCR3, CCR5, and CXCR4 U87MG.CD4 transformed cell lines and STRL33/BONZO/TYMSTR and GPR15/BOB HOS.CD4 transformed cell lines. Primary viruses were isolated from 79 men with confirmed human immunodeficiency virus type 1 (HIV-1) infection from the Chicago component of the Multicenter AIDS Cohort Study at interval time points. Thirty-five additional well-characterized primary viruses representing HIV-1 group M subtypes A, B, C, D, and E and group O and three primary simian immunodeficiency virus (SIV) isolates were also used for these studies. The restricted use of the CCR5 chemokine receptor for viral entry was associated with infection by a virus having a non-syncytium-inducing phenotype and correlated with a reduced rate of disease progression and a prolonged disease-free interval. Conversely, broadening chemokine receptor usage from CCR5 to both CCR5 and CXCR4 was associated with infection by a virus having a syncytium-inducing phenotype and correlated with a faster rate of CD4 T-cell decline and progression of disease. We also observed a greater tendency for infection with a virus having a syncytium-inducing phenotype in men heterozygous for the defective CCR5 Delta32 allele (25%) than in those men homozygous for the wild-type CCR5 allele (6%) (P = 0.03). The propensity for infection with a virus having a syncytium-inducing phenotype provides a partial explanation for the rapid disease progression among some men heterozygous for the defective CCR5 Delta32 allele. Furthermore, we did not identify any primary viruses that used CCR3 as an entry cofactor, despite this CC chemokine receptor being expressed on the cell surface at a level commensurate with or higher than that observed for primary peripheral blood mononuclear cells. Whereas isolates of primary viruses of SIV also used STRL33/BONZO/TYMSTR and GPR15/BOB, no primary isolates of HIV-1 used these particular chemokine receptor-like orphan molecules as entry cofactors, suggesting a limited contribution of these other chemokine receptors to viral evolution. Thus, despite the number of chemokine receptors implicated in viral entry, CCR5 and CXCR4 are likely to be the physiologically relevant chemokine receptors used as entry cofactors in vivo by diverse strains of primary viruses isolated from blood.

Animals↗
PubMed1998

Characterization and localization of the genes for mouse proteinase-3 (Prtn3) and neutrophil elastase (Ela2).

Proteinase-3 (PR-3) and neutrophil elastase (NE) are polymorphonuclear leukocyte serine proteinases that degrade extracellular matrix proteins including elastin and appear to be involved in the pathogenesis of several diseases characterized by tissue destruction most notably emphysema and Wegener's granulomatosis. In this report we characterize and compare the mouse PR-3 and NE genes and establish by FISH analysis a common location on mouse chromosome 10C2. Each gene consists of five exons and four introns conserving the typical granule-associated serine proteinase gene structure. The mouse PR-3 gene (Prtn3) is approximately 3.7 kb and is within 2.2 kb of the smaller (1.7 kb) NE gene (Ela2). The larger size of Prtn3 is accounted for by differences in intron sizes. A comparison between the mouse and human PR-3 cDNA reveals 73% homology, however, this drops to 60% when the amino acid sequences are compared. Homology between the mouse and human NE cDNA is 77% for both the cDNA and amino acid sequences. The catalytic triad and its placement are conserved among the four genes. The proximal promoter of mouse Prtn3 contains a TATA box, c-myb and an ets transcriptional site. As these are functional elements in the mouse Ela2 promoter they may also be important in the expression of Prtn3.

Animals↗
PubMed1998

The N-terminal portion of parathyroid hormone-related protein mediates the inhibition of apical Na+/H+ exchange in opossum kidney cells.

Parathyroid hormone (PTH) and PTH-related protein (PTHrP) can activate a common receptor in several different cell types. Both PTH and N-terminal PTHrP peptides have been shown to acutely inhibit the apical Na+/H+ exchanger in the renal proximal tubule. In this study, the ability of various PTHrP fragments to inhibit apical Na+/H+ exchange was investigated. In addition, the signal transduction events associated with PTHrP inhibition of apical Na+/H+ exchange in polarized OK-P cells were characterized. Both PTHrP-(1-34)NH2 and recombinant full-length PTHrP-(1-141) inhibited apical Na+/H+ exchange activity by approximately 50%. These changes occurred in close temporal association with significant (threefold) increases in cellular cAMP accumulation. PTHrP-(1-34)NH2 had no effect on intracellular Ca2+, inositol phosphate production, or protein kinase C activity. PTHrP peptides, including PTHrP-(38-64)NH2, PTHrP-(67-86)NH2, PTHrP-(102-107)NH2, and PTHrP-(107-139)NH2, which lack the PTH-like N terminus, had no effect on the antiporter activity or cAMP accumulation. The results demonstrate that the N-terminal portion of the PTHrP molecule is responsible for inhibition of the apical Na+/H+ antiporter in OK-P cells.

Animals↗
PubMed1998

Vinculin and cell-cell adhesion.

Vinculin, a 117-kDa protein, is a constituent of adhesion plaques and adherence junctions in non-muscle cells. We investigated the role of vinculin on the physical strength of cell-cell adhesion by conducting disaggregation assays on aggregates of parental wild-type F9 mouse embryonal carcinoma cells (clone BIM), two vinculin-depleted F9 cell lines, gamma 227 and gamma 229, and a reconstituted gamma 229 cell line (R3) that re-express vinculin. Immunoblotting demonstrated that the four cell lines used in the study had similar expressions of the cell-cell adhesion molecule E-cadherin and associated membrane proteins alpha- and beta-catenin. Double immunofluorescence analysis showed that, in contrast to the vinculin-null cell lines. BIM and R3 cells expressed abundant vinculin at the cell margins in adhesion plaques and in cell-cell margins that also contained actin. Laminar flow assays showed that both the vinculin-positive and vinculin-negative cell aggregates that were formed in culture in the course of 24 to 48 hours largely remained intact despite the imposition of shear flow at high shear rates. Since laminar flow imposed on cell aggregates act to separate cells from each other, our data indicate that F9 cells that were adherent to a substrate formed strong cell-cell adhesion bonds independent of vinculin expression. On the other hand, aggregates of vinculin-depleted gamma 229 and gamma 227 cells that were formed in suspension during a two-hour static incubation at 37 degrees C were desegregated more easily with the imposition of shear flow than the BIM and R3 cell aggregates formed under identical conditions. Loss of vinculin was associated with a reduction in cell-cell adhesion strength only among those cells lacking contact to a substrate. Overall, the results indicate that vinculin is not needed for forming strong cell-cell adhesion bonds between neighboring carcinoma cells which are adherent to the basal lamina.

Actins↗
PubMed1998

The carriage of Escherichia coli resistant to antibiotics in healthy populations in Shanghai.

Healthy populations represent the largest reservoir of bacteria resistant to antibiotics. We investigated the resistance of Escherichia coli to 12 antibiotics in fecal samples from untreated healthy populations in Shanghai, China by using Kirby-Bauer (K-B) method. The results showed that: (i) All subjects carried resistant strains of Escherichia coli. (ii) The carriage rates of Escherichia coli resistant to various antibiotics were different, less than 10% to amikacin and 30% to 100% to others. (iii) In the elder children group aged 10-11 years, the percentages of strains resistant to gentamicin, streptomycin, chloramphenicol, tetracycline, trimethoprim, and sulfamethoxazole were significantly lower than those in the younger group aged 5-6 years. In the adult group, the percentages of strains resistant to ampicillin, piperacillin, amikacin, streptomycin, chloramphenicol, tetracycline, trimethoprim, and sulfamethoxazole were significantly lower than those in the elder children group. (iv) The number of strains resistant to five or more antibiotics accounted for 31.8% in the younger children group, 23.7% in the elder children group, and 12.1% in the adult group. These findings suggest that all healthy people in Shanghai carry resistant strains of Escherichia coli in the intestine. The younger the populations, the higher the level of resistance of fecal Escherichia coli to antibiotics. Improvement of health behaviors and environmental sanitation and rational use of antibiotics could remarkedly decrease the resistant level of bacteria.

Adult↗
PubMed1998

[Long-term result of free forearm skin flap for repair of soft tissue defects of the oral and maxillofacial regions].

To evaluate the long-term result of free forearm skin flap in the repair of soft tissue defects of the oral and maxillofacial regions, 26 cases which had received radical resection of maxillofacial tumors were follow-up for 4.5 years. Twenty cases, having complete data were analyzed. In this series, There were 8 males and 12 females, with ages ranged from 40 to 69 years old. The size of the flaps ranged from 4 cm x 5 cm-6 cm x 13 cm. The radial artery and the cephalic vein were used as the donor vessels, and the maxillary artery, superior thyroid artery, external jugular vein and the anterior jugular vein were prepared as the recipient vessels. According to the shape, colour, temperature, sensation, mucosoid degree of the flap, the blood supply and function of hand and the configuration of the forearm, the overall results of the recepient regions in 20 cases were all satisfactory and the overall results of 16 cases donor regions were satifactory in 16 cases. The results were poor in 4 cases. The conclusion were: 1. Free forearm skin flap was worth trying in the repair of soft tissue defects of oral region; 2. The radial artery need not to be reconstructed because of the abandant vascular net-work in the upper limb and 3. The residual scar on the forearm was the main shortcoming, but most of the patients could tolerate it because of the obvious advantages received from the operation.

Adult↗
PubMed1998

The stress-bearing ability of mucosa in complete denture-wearers.

OBJECTIVE: The purpose of this study was to investigate the stress-bearing ability of mucosa in complete denture-wearers. METHODS: The maximum bite force (MBF) was obtained in 31 voluntary complete denture-wearers with a miniature bite force instrument and a set of central bearing devices. The projective stress-bearing area in the mandible (PAM) was measured through the impression surface of the mandibular complete denture. The authors evaluated the stress-bearing ability (SBA) of mucosa in complete denture-wearers by the formula MBF/PAM. RESULTS: The results showed that there was a significant positive correlation between the MBF (the mean was 15.13 kg in men and 11.39 kg in women) and the PAM (the mean was 17.15 cm2 in men and 14.46 cm2 in women) and that there was no significant difference between the mean of the SBA in men (0.89 kg/cm2) and the mean of the SBA in women (0.79 kg/cm2). The mean value of the maximum pressure borne by the mandibular edentulous region was 82 kPa (0.84 kg/cm2). CONCLUSIONS: The SBA may become a valuable parameter for the design of both occlusion and reinforcement in the denture construction and for the selection of the maximum load in mechanical tests of complete dentures.

Aged↗
PubMed1998

[Relationship between sex hormone levels and blood lipids/immunity in perimenopausal women].

To investigate the relationship between sex hormone levels and blood lipids/immunity and to evaluate the therapeutical effects of nylestriol, 96 women without coronary heart disease(CHD) were studied during their perimenopausal period. The estimation of serum biochemical components included serum 17 beta-estradiol(E2), testosterone(T), total cholesterol(TC), triglyceride (TC), high density lipoprotein cholesterol(HDL-C), low density protein cholesterol(LDL-C), apolipoprotein A-I(ApoAI), apolipoprotein B(ApoB), lipoprotein (a)[Lp(a)], immunoglobulin G(IgG), and IgG antibody against cardiolipin(ACAIgG). Thirty-six postmenopausal volunteers were divided into two groups and randomized to treat with either 2 mg nylestriol or placebo. In postmenopausal women, serum levels of E2, E2/T, HDL, and ApoAI decreased, while those of T, TC, TG, LDL, ApoB, Lp(a), IgG, and ACAIgG increased. Serum level of E2 was positively correlated to HDL-C and negatively correlated to TC, ApoB, LDL, IgG, and ACAIgG. Serum level of T was positively correlated to LDL, IgG, and ACAIgG and negatively correlated to HDL. In the nylestriol group, as compared with the results before treatment, serum levels of TG, TC, LDL, IgG, and ACAIgG decreased and that of HDL-C increased after treatment. We conclude that estradiol is a protective factor of CHD, whereas testerone is a dangerous factor. After menopause, the imbalance of the estradiol/testosterone ratio increases the incidence of CHD. Nylestriol is an effective substitute for estradiol to prevent CHD in post menopausal women.

Cholesterol↗
PubMed1998

[Chronic pulmonary heart diseases treated by fraxiparin].

OBJECTIVE: The effects of fraxiparine with hypodermic on the treatment of patients with chronic pulmonary heart diseases(CPHD) at acute phase were studied. METHODS: Twenty patients were hypodermically injected with 0.4 ml fraxiparine per day for 7 days as a course. Fibrin fibrinogen degradation products (FDP and D-dimer), antithrombin III (AT-III), PaO2 and PaCO2 were detected before and after the treatment. RESULTS: In the therapy group, FDP and D-dimer decreased after the treatment, AT-III increased. All indexes didn't alter in the control group. CONCLUSION: Fraxiparine is effective on patients with CPHD at acute phase.

Adult↗
PubMed1998

[Randomized comparative study of GyneFix IN and TCu 380A intrauterine devices].

OBJECTIVE: To observe the clinical performances of the new intrauterine device (IUD)-GyneFix IN. METHODS: The present study is a randomized comparative clinical trial. 607 healthy parous women were randomly allocated into GyneFix IN group (n = 302) or TCu 380A group (n = 305). IUD was inserted during the menstrual interval by the trained investigators. Follow-up were arranged at 1, 3, 6 and 12 months after insertion. The discontinuation rates were calculated by life table method. RESULTS: At the end of the first year, there was no pregnancy occurred in GyneFix IN group. Its expulsion rate and removal rate for medical reasons were 2.67 and 1.02 per 100 women respectively. The use-related discontinuation rates was 3.66, which was significantly lower than that in the TCu 380A group (7.88, P < 0.05). The number of women with complaint of pain was also less in GyneFix IN group. CONCLUSION: The excellent performance of the new IUD which is a frameless device with high copper surface and anchoring system was confirmed by this multicentre trial. Due to lower expulsion rate and less side effect of pain, it could be recommended.

Adolescent↗
PubMed1998

[Telomerase activity in infiltration ductal carcinoma of breast].

OBJECTIVES: To compare telomerase activity of infiltration ductal carcinoma of breast with that of benign breast changes and to analyze the significance of telomerase activity in diagnosis of malignancy. METHOD: Telomerase activity was detected in 61 cases of infiltration ductal carcinomas of breast and 14 cases of benign changed breast using TRAP assay. RESULTS: Telomerase activity was detected in 49 of 61 (80.3%) cases of infiltration ductal carcinoma. Telomerase activity in infiltration ductal carcinoma was not related tumor grades, tumor size, lymph node metastasis status, even tumor tissue estogen receptor(ER) and progesterone receptor(PR) status. Telomerase activity was not present in 5 cases of breast fibrocystic disease. Weak telomerase activity was detected in 4 of 9 cases of breast fibroadenoma. These suggested that telomerase activity acquires in very early stage of breast cancer. CONCLUSION: Telomerase activity is only detected in most of infiltration ductal carcinomas of breast and few cases of fibroadenoma. Telomerase activity may play an important role in the development of breast cancer.

Breast Neoplasms↗
PubMed1998

[Study on telomerase activity in hepatocellular carcinoma and chronic hepatitic disease].

OBJECTIVE: To compare telomerase activity of hepatocellular carcinoma (HCC) with that of chronic liver disease to analyze the significance of telomerase activity in diagnosis of malignancy. METHODS: Telomerase activity was detected in 38 cases of HCC and corresponding non-tumor liver tissue with different chronic disease. That is 21 cases of hepatic cirrhosis, 2 cases of mild fibrosis, 2 cases of chronic viral hepatitis and 7 cases of non-tumor liver with no significant histopathological changes using TRAP assay. 4 cases of biliary atresia were also detected and 4 cases of normal liver tissue were the control. RESULTS: Telomerase activity was detected in 32 of 38 (86.8%) cases of HCC. Telomerase activity in HCC was not related with tumor cell differentiation types, tumor size and HBV infection, but expression of telomerase was highly correlated with serum alpha-fetal protein (AFP) level of patients. Telomerase negative HCC group has statistically significant lower level of AFP (P < 0.01) when compared with telomerase positive HCC groups. Telomerase activity was not present in normal liver tissue (0/4), biliary atresia (0/4), mild fibrosis (0/2), chronic viral hepatitis (0/4) and no significant changes of non-tumor liver tissue (0/7). Weak telomerase activity was detected in 4 of 21 hepatic cirrhosis. CONCLUSION: Telomerase activity was only detected in most of HCC and few cases of hepatic cirrhosis, which may play a crucial role in hepatocarcinogenesis and may be useful for the diagnosis of malignancy.

Carcinoma, Hepatocellular↗