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Biomedical subjects

M Wang

Publications and source records attributed to M Wang.

At least 451 records · Page 25Linked to original sources
PubMed1999

Growth of HPV-18 immortalized human prostatic intraepithelial neoplasia cell lines. Influence of IL-10, follistatin, activin-A, and DHT.

Cultures from high grade prostatic intraepithelial neoplasia (HGPIN) have been established and immortalized by HPV-18 infection. The cultures were identified as PIN by Western blotting with anti-cytokeratin (34betaE12) and prostate specific antigen (PSA) antibodies. We examined the growth capabilities of the cultures in the presence of TGF-beta1, activin-A, follistatin (FS), androgens (DHEA, DHT) and several cytokines (IL-10, IL-2, IL-4). IL-10, FS, and DHT stimulated cell proliferation and colony forming ability, while the other cytokines and growth factors had no discernable effect. In addition, DHT and to a lesser extent IL-10 both stimulated PSA production. Activin-A blocked IL-10, FS, and DHT stimulated growth and PSA production. We interpret the data to mean that IL-10 induction of FS secretion (and FS binding of activin A) restores the normal growth capabilities of HGPIN cultures.

Activins↗
PubMed1999

Expression of apoptosis-related genes in human head and neck squamous cell carcinomas undergoing p53-mediated programmed cell death.

Human head and neck squamous cell carcinoma (HNSCC) lines infected with a replication-defective Ad5CMV-p53 vector bearing a wild-type human p53 gene were used to examine alterations in the production of proteins implicated in regulating apoptosis. Because HNSCC lines express abundant levels of c-myc, and simultaneous expression of c-myc and p53 is known to trigger apoptosis in other cells, cooperation between these two genes was examined. Surprisingly, levels of c-myc mRNA and protein were rapidly and profoundly suppressed after infection with wild-type p53. Suppression of c-myc using antisense oligodeoxynucleotides (in the absence of p53) was sufficient to trigger apoptosis in Tu-138 cells, raising the possibility that the reduction of c-myc may be involved in at least one of the cell death pathways mediated by p53. Expression of a panel of Bcl-2 homology proteins was also examined in HNSCC lines undergoing p53-mediated apoptosis. No changes in Bcl-2, Bak, or Bcl-xS were found after p53 expression. Increased levels of the apoptosis-accelerating protein Bax were found in HNSCC lines after infection with Ad5CMV-p53. Induction of the apoptosis-inhibiting protein Bcl-xL was observed in Tu-167 cells and may account for the delayed onset of apoptosis in these cells. These studies suggest that multiple pathways may regulate apoptosis after transient overexpression of p53.

Apoptosis↗
PubMed1999

Role of interleukin 10 and transforming growth factor beta1 in the angiogenesis and metastasis of human prostate primary tumor lines from orthotopic implants in severe combined immunodeficiency mice.

Transfection of primary human prostate tumor cells (i.e., HPCA-10a, 10b, 10c, and 10d lines) with the transforming growth factor (TGF)-beta1 gene stimulated anchorage-independent growth and promoted tumor growth, angiogenesis, and metastasis after orthotopic implantation in severe combined immunodeficiency mice. In contrast, interleukin (IL)-10 transfected cells or cells cotransfected with these two genes exhibited reduced growth rates and significantly reduced angiogenesis and metastasis after 8, 12, and 16 weeks. Enzyme-linked immunosandwich assays confirmed that the respective tumors expressed elevated levels of TGF-beta1 and IL-10 in vivo. ELISAs further showed that TGF-beta1 expression induced matrix metalloproteinases-2 (MMP-2) expression, whereas IL-10 down-regulated MMP-2 expression while up regulating TIMP-1 in the transfected cells. Also, tumor factor VIII levels correlated with TGF-beta1 and MMP-2 expression and inversely with IL-10 and TIMP-1 levels. More importantly, mouse survival was zero after 4-6 months in mice bearing TGF-beta1- and MMP-2-expressing tumors and increased significantly in mice implanted with IL-10- and TIMP-1-expressing tumors (i.e., to >80% survival). Analysis of the metastatic lesions showed that they expressed TGF-beta1 and MMP-2 but barely detectable levels of IL-10 or TIMP-1, suggesting that IL-10 and TIMP-1 might normally block tumor growth, angiogenesis, and metastasis.

Animals↗
PubMed1999

Thrombopoietin has a differentiative effect on late-stage human erythropoiesis.

To further explore the mechanism of the effect of thrombopoietin (TPO) on erythropoiesis, we used a two-phase culture system to investigate the effect of TPO on late-stage human erythroid lineage differentiation. In serum-free suspension and semisolid cultures of human peripheral blood derived erythroid progenitors, TPO alone did not produce benzidine-positive cells. However, in serum-containing culture, TPO alone stimulated erythroid cell proliferation and differentiation, demonstrated by erythroid colony formation, production of benzidine-positive cells and haemoglobin (Hb) synthesis. Monoclonal anti-human erythropoietin antibody and anti-human erythropoietin receptor antibody completely abrogated the erythroid differentiative ability of TPO in the serum-containing systems. This implied that binding of EPO and EPO-R was essential for erythropoiesis and the resultant signal transduction may be augmented by the signals emanating from TPO-c-Mpl interaction. Experiment of withdrawal of TPO further demonstrated the involvement of TPO in late-stage erythropoiesis. RT-PCR results showed that there was EPO-R but not c-Mpl expression on developing erythroblasts induced by TPO in serum-containing system. Our results establish that TPO affects not only the proliferation of erythroid progenitors but also the differentiation of erythroid progenitors to mature erythroid cells.

Cell Differentiation↗
PubMed1999

Acute effects of thirty minutes of light-intensity, intermittent exercise on patients with chronic fatigue syndrome.

BACKGROUND AND PURPOSE: Currently, there is no consensus on exercise prescription for patients with chronic fatigue syndrome (CFS). This investigation examined whether light-intensity, intermittent physical activity exacerbated symptoms in patients with CFS immediately following exercise to 7 days following exercise. Subjects. Subjects were 9 women (mean age=44.2 years, SD=8.4, range=29-56; mean weight=74.2 kg, SD=18.8, range=56.36-110.91; and mean height=1.63 m, SD=0.8, range=1.55-1.78) and 1 man (age=48 years, weight=97.1 kg, and height= 1.98 m) who met the Centels for Disease Control and Prevention's criteria fi)r (FS. METHODS: Subjects performed 10 discontinuous 3-minute exercise bouts (separated by 3 minutes of recovery) at a self-selected, comfortable walking pace on a treadmill. Oxygen consumption, minute ventilation, respiratory exchange ratio, and heart rate were measured every minute during the exercise session. To assess degree of disability, general health status, activity level, symptoms, and mood, subjects completed various questionnaires before and after exercise. RESULTS: Results indicated that degree of disability, general health status, symptoms, and mood did not change immediately and up to 7 days following exercise. CONCLUSION AND DISCUSSION: Thirty minutes of intermittent walking did not exacerbate symptoms in subjects with CFS. The physiological data did not show any abnormal response to exercise. Although this study did not determine whether 30 minutes of continuous versus intermittent exercise would exacerbate symptoms, all 10 subjects felt that they could not exercise continuously for 30 minutes without experiencing symptom exacerbation. Despite this limitation, the results indicate that some individuals with CFS may be able to use low-level, intermittent exercise without exacerbating their symptoms.

Adult↗
PubMed1999

A 12-Mb complete coverage BAC contig map in human chromosome 16p13.1-p11.2.

We have constructed a complete coverage BAC contig map that spans a 12-Mb genomic segment in the human chromosome 16p13.1-p11.2 region. The map consists of 68 previously mapped STSs and 289 BAC clones, 51 of which-corresponding to a total of 7.721 Mb of genomic DNA-have been sequenced, and provides a high resolution physical map of the region. Contigs were initially built based mainly on the analysis of STS contents and restriction fingerprint patterns of the clones. To close the gaps, probes derived from BAC clone ends were used to screen deeper BAC libraries. Clone end sequence data obtained from chromosome 16-specific BACs, as well as from public databases, were used for the identification of BACs that overlap with fully sequenced BACs by means of sequence match. This approach allowed precise alignment of clone overlaps in addition to restriction fingerprint comparison. A freehand contig drawing software tool was developed and used to manage the map data graphically and generate a real scale physical map. The map we present here is approximately 3.5 x deep and provides a minimal tiling path that covers the region in an array of contigous, overlapping BACs.

Base Sequence↗
PubMed1999

[Cloning and expression analyses of down-regulated cDNA C6-2A in human esophageal cancer].

OBJECTIVE: To clone genes associated with the genesis of human esophageal cancer. METHODS: Identifying missing or low expressing cDNAs in human esophageal cancer tissues by mRNA differential display and examining its mRNA expression in 4 human cancer cell lines, 9 fetal tissues and other matched esophageal cancer tissues by Northern blot, dot blot and RT-PCR. RESULTS: One cDNA fragment named C6-2A, was cloned and sequenced. There was no identical sequence with C6-2A in BLASTN database; but in querying Genbank EST, the authors found that C6-2A was identical with ne27b03.s1NCI-CGAP-C03 humans sapiens cDNA clone IMAGE:898541 3' and zv30g07.rl Soares ovary tumor NbHOT homo sapiens cDNA clone 755196. 6/6 esophageal cancer tissues in Northern blot and 7/8 in dot blot did not or slightly express C6-2A. RT-PCR analysis showed that C6-2A was expressed much lower in 17/20 esophageal cancer tissues than adjacent microscopically normal mucosa, highly expressed in fetal esophageal mucosa, skin, cerebrum, placenta; moderately expressed in fetal stomach and liver, but not detected in fetal heart, small intestine and kidney. CONCLUSION: The high frequency of deletion of decreased expression of C6-2A in esophageal cell lines and human esophageal cancer tissues suggested that C6-2A might be involved in the carcinogenesis of esophagus.

Cloning, Molecular↗
PubMed1999

Relation between interleukin-1beta messenger RNA in gastric fundic mucosa and gastric juice pH in patients infected with Helicobacter pylori.

The effects of Helicobacter pylori infection on gastric acid secretion has not been clarified. The aim of this study was to elucidate the effects of H. pylori infection on gastric juice pH in relation to gene expression of interleukin-1beta (IL-1beta), which is reported to inhibit gastric acid secretion. Gastric juice pH and serum gastrin levels were measured in patients with peptic ulcer disease. The amount of IL-1beta mRNA in gastric fundic gland mucosa was also measured by a competitive reverse transcription-polymerase chain reaction method. These parameters were determined before and after treatment with lansoprazole and amoxicillin. Before treatment a significant positive relation was observed between the amount of IL-1beta mRNA in gastric fundic gland mucosa and gastric juice pH. After treatment significant decreases in the amount of IL-1beta mRNA, gastric juice pH, and serum gastrin levels were observed in patients with eradication of H. pylori, whereas no significant changes were observed in patients without eradication. These results suggest that H. pylori infection induces IL-1beta and suppresses acid secretion, resulting in increases in gastric juice pH and serum gastrin levels. Eradication of H. pylori decreases IL-1beta induction, resulting in an increase in gastric juice acidity and normalization of serum gastrin levels.

Base Sequence↗
PubMed1999

Reactions of alpha-acetoxy-N-nitrosopyrrolidine and crotonaldehyde with DNA.

alpha-Acetoxy-N-nitrosopyrrolidine (alpha-acetoxyNPYR) is a stable precursor to alpha-hydroxyNPYR, the initial product of metabolism and proposed proximate carcinogen of NPYR. Crotonaldehyde (2-butenal) is a metabolite of NPYR and also a mutagen and carcinogen. Both alpha-acetoxyNPYR and crotonaldehyde are known to form DNA adducts, but these reactions have not been completely characterized. In previous studies, we detected substantial amounts of unidentified radioactivity in hydrolysates of DNA that had been reacted with radiolabelled alpha-acetoxyNPYR. We have now characterized these products as 2-hydroxytetrahydrofuran, the cyclic form of 4-hydroxybutanal, and paraldol, the dimer of 3-hydroxybutanal. They were characterized by comparison with standards and by comparison of their derived 2,4-dinitrophenylhydrazones with standards. [3H]H2O was also identified. 2-Hydroxytetrahydrofuran is the major product in neutral thermal hydrolysates of alpha-acetoxyNPYR-treated DNA and is derived predominantly from N2-(tetrahydrofuran-2-yl)deoxyguanosine 8. Paraldol is present to a lesser extent than 2-hydroxytetrahydrofuran in these reactions and is formed from paraldol-releasing adducts, which in turn are produced by the reaction of crotonaldehyde or paraldol, solvolysis products of alpha-acetoxyNPYR, with DNA. Paraldol is a major product in hydrolysates of crotonaldehyde-treated DNA, being present in amounts 100 times greater than those of previously identified adducts. These results provide a more complete picture of the reactions of alpha-acetoxyNPYR with DNA and yield some new insights on possible endogenous DNA adducts formed from crotonaldehyde.

Aldehydes↗
PubMed1999

Antiviral effects of rhIFN-alpha 1 against seven influenza viruses.

AIM: To study the antiviral effects of rhIFN-alpha 1 (Chinese silkworm gene recombinant interferon alpha 1) on 7 influenza viruses in MDCK cells and in mouse pneumonia caused by PR8 virus. METHODS: 100TCID50 virus (H1N1, H2N2, H3N3, type B, type C, clinical A1, and clinical B) were inoculated into MDCK cells, PR8 viruses were dropped nasally in mice, the antiviral effects of rhIFN-alpha 1 were observed. RESULTS: The minimal effective concentrations of rhIFN-alpha 1 against these 7 influenza viruses were 12.5, 25, 50, 25, 12.5, 25, and 12.5 kU.L-1, respectively. The infectious therapeutic indices of rhIFN-alpha 1 to these viruses in MDCK cells were 8 x 10(3), 4 x 10(3), 2 x 10(3), 4 x 10(3), 8 x 10(3), 4 x 10(3), and 8 x 10(3), respectively. The inhibitory indices of rhIFN-alpha 1 to the 7 influenza viruses in MDCK cells were 3.6, 4.7, 3.5, 3.3, 3.9, 4.6, and 3.5, respectively. The rhIFN-alpha 1 inhibited the intracellular replication of influenza viruses effectively, but did not kill viruses directly. The rhIFN-alpha 1 prolonged the life span of mice infected with pneumonia by influenza virus A strain PR8 to 94.2%-132.7%. It inhibited the inflammation and hyperplasia of interstitial fibers, and decreased the virus titer. The inhibitory rates of rhIFN-alpha 1 to pulmonary-indice were 14.8%-37.4%. CONCLUSION: rhIFN-alpha 1 inhibited the proliferation of influenza virus and improved the symptom of mouse pneumonia caused by influenza virus.

Animals↗
PubMed1999

[A case-control study on the dietary risk factors of upper digestive tract cancer].

OBJECTIVE: To understand the effect of dietary factors in Yangzhong, Jiangsu Province-a high prevalence area in China. METHODS: A case-control study on 209 cases of upper digestive tract cancer was conducted. There were 68 cases of esophageal cancer, 69 cases of cardiac cancer and 72 cases of other gastric cancers including 129 males and 80 females aged 35-79 under the study. RESULTS: It is revealed that intake of pickled vegetables increases the ORs of esophageal, cardiac and other gastric cancers (OR = 2.82, OR = 5.17, OR = 2.92, respectively). It is also concluded that the intake of leftovers can elevate the ORs of esophageal and cardiac gastric cancer (OR = 1.88 and OR = 1.90) and over consumption of salt also elevates the OR of cardiac cancer (OR = 1.87). However, drinking green tea may decrease the ORs of esophageal and other gastric cancers (OR = 0.20 and OR = 0.28) while fruits consumption may reduce the OR of esophageal cancers (OR = 0.51). CONCLUSION: Tumors from upper digestive tract have some relations with diet factors but the effects vary with the differences of tumor sites, dose of exposure and area, etc.

Adult↗
PubMed1999

Purification and characterization of a novel fibrinolytic enzyme from Streptomyces spp.

A novel protease with fibrinolytic activity, designated as SW-1, was isolated and purified from the fermentation broth of Streptomyces sp. strain Y405, a soil isolate. The purification procedure involved ammonium sulphate fractionation, decolorization on 290 resin, gel filtration on Sephadex G75, anion-exchange chromatography on DEAE Sephadex A25, and affinity chromatography on Lysine Sepharose 4B. About 4.2 mg purified enzyme was obtained from a liter of fermentation broth and the recovery yield was 12.0%. The purified enzyme showed the specific activity of 2952.3 urokinase units per milligram, which was increased by 230.6 fold over the fermentation broth. The purity determined by HPLC was 83.5%. SW-1 is a single chain polypeptide with a predicted molecular weight of 30 kDa in SDS-PAGE and an isoelectric point of 8.5. The N-terminal sequence of SW-1 is R/N/F-P/D-G-M-T-M-T-A-I-A-N-Q-N-T-Q-I-N. There may be nonhomogeneity in the first and second amino acid residue of its N-terminal sequence. The analysis of amino acid composition showed that SW-1 consisted of 262 amino acids. The fibrinolytic activity of SW-1 was entirely inhibited by 10 mmol/L PMSF, 1 mmol/L EDTA and 1 mol/L lysine, respectively, suggesting that SW-1 is a serine protease and metalloprotease, and that the lysine binding site might play a role in the activity. The fibrinolytic activity of SW-1 is stable between 4-37 degrees C and pH 4.0-9.0, and the optimum pH is 8.0. On plasminogen-free fibrin plates, SW-1 showed the same fibrinolytic activity as the mixture of SW-1 with plasminogen, indicating that SW-1 is a fibrinolytic enzyme which affects fibrin directly, but not a plasminogen activator which affects fibrin by activating plasminogen.

Amino Acid Sequence↗
PubMed1999

[Study of the inhibitory effects of retrovirus-mediated p16 gene on human ovarian cancer cell line].

OBJECTIVE: To study the inhibitory effects of retro-virus-mediated p16 gene on human ovarian cancer cell line CAOV3. METHODS: Recombinant eukaryotic expression vector pDOR-p16 containing exogenous human wt-p16 cDNA and vector with neomycin resistance gene only were introduced by lipofectamine-mediated gene transfection into CAOV3 cell line which does not express p16 endogenously. By using revert-polymerase chain reaction amplification, mRNA in situ hybridization and immunocytochemistry, the clones obtained were detected for their efficiency of transfection and effects of vector expression and observed for their biologic behavior. RESULTS: Exogenous wt-p16 had successfully been transferred into CAVO3 cells and obtained permanent expression. The growth rate of these transfected CAOV3 cells in regular medium and soft agar was inhibited, and the tumorigenicity in nude mice showed that two in four mice failed to form tumor and the others suffered from tumor later than contrast group by 7 to 14 days. The percentage of phase G1 cells increased and that of phase S cells decreased by analysing cell cycle. The ultrastructural changes of the cells were observed under electron microscope, revealing necrosis and growth retardation. CONCLUSIONS: p16 gene played an important role in generation and development of ovarian carcinoma. This study might provide the experimental evidence for the gene therapy in human ovarian cancer.

Cell Division↗
PubMed1999

Angiotensin-(1-7) antagonist [D-Ala7-Ang-(1-7);A-779] attenuates post-suspension hypotension in Sprague-Dawley rats.

Cardiovascular deconditioning manifested by reduction in mean arterial pressure (MAP) and cardioaccleration are usually observed in astronauts during standing postflight. The head-down tilt (HDT) rat model with "unloaded" hindlimbs has been extensively studied because some of the observed responses mimic observations made during exposure to microgravity. Angiotensin-(1-7) is a biologically active component of the renin-angiotensin system that acts to oppose the pressor and proliferative actions of Angiotensin II. It produces a hypotensive response by either stimulating production of vasodilator prostaglandins (i.e., prostacyclin), increasing nitric oxide or both. In the present study, we have evaluated the role of a specific inhibitor of Ang-(1-7), D-Ala7-Ang-(1-7)[A-779], as a countermeasure against post-suspension hypotension.

Angiotensin II↗
PubMed1999

Influence of simulated microgravity on cardiovascular and hemodynamic parameters in Dahl salt-sensitive rats.

Prolonged exposure to microgravity, in humans, induces cardiovascular deconditioning and impairment of baroreflex activity partially as a result of fluid and electrolyte shifts. Animal models of simulated microgravity have been developed to mimic the above responses. We examined the effects of both 24 hr whole body suspension and 7 day tail-suspension and the subsequent 6 hr post-suspension in salt-loaded (2 wks on 8% NaCl diet) Dahl salt-sensitive rats. In both models, mean arterial pressure (MAP) and heart rate (HR) were unchanged during the suspension period. Upon release from suspension, there was no difference in the MAP or HR responses. Blood flows measured in the lower abdominal aorta and renal artery were not different between suspended and control animals. In both models, there was a similar body weight reduction in all groups. MAP responses to both phenylephrine (PHE) and sodium nitroprusside (SNP) were not affected by simulated microgravity. The HR response to SNP in suspended animals was greater than that of control animals; whereas, PHE-induced responses were not different. These data support the notion that simulated microgravity did not alter the MAP responses to SNP and PHE, however, HR responses were enhanced by SNP in the salt-loaded Dahl rats. In addition, salt-sensitivity/salt-loading prevents the reduction in MAP observed post-suspension in normotensive rats.

Animals↗
PubMed1999

Diagnosis of gastroesophageal reflux disease in elderly subjects using 24-hour esophageal pH monitoring.

OBJECTIVE: To evaluate the relationship between the parameters of 24-hour esophageal pH monitoring and gastroesophageal reflux disease (GERD) among elderly subjects. METHODS: Twenty-four-hour esophageal pH monitoring was carried out in 20 elderly subjects without apparent GERD symptoms (controls) and 69 suspected GERD subjects. RESULTS: Normal values of the parameters from 20 elderly controls were obtained. Percent of total time, percent of supine time and percent of upright time in which the pH was < 4 (indicating reflux) were less than 3.3%, 1.4%, 5.5%, respectively. The number of reflux episodes and episodes lasting longer than 5 minutes were less than 65 and 2 times respectively. The values obtained in 66 GERD suspected subjects were significantly different from those in normal controls. The differences of reflux parameters between the esophagitis group and non-esophagitis group, such as percent of total time with pH < 4, percent of supine time with pH < 4 and number of reflux lasting longer than 5 minutes were also significant. CONCLUSIONS: About 51.6% patients (34/66) with reflux symptoms but without endoscopic evidence of esophagitis were definitely diagnosed as GERD by esophageal pH monitoring. Duration of esophageal acid exposure correlated with the severity of GERD.

Aged↗
PubMed1999

Postoperative radiotherapy for stage I thymoma: a prospective randomized trial in 29 cases.

OBJECTIVE: To determine the effect of postoperative radiotherapy on stage I thymoma. METHODS: Twenty-nine patients with stage I thymoma younger than 65 years, treated between August 1981 and January 1996 were included in this study. All patients were randomly assigned into two groups: surgery alone (13 patients) and surgery with postoperative radiotherapy (16). Staging was based on the surgical and pathologic criteria that the tumor had a complete capsule and without capsular invasion microscopically. Adjuvant radiotherapy was started within 4 weeks after surgery. Megavolage radiation, using the isocentric technique, was administered through an anterior field and/or two anterior oblique wedge fields. For the patients with lymphocytic predominant type, the dose was 50 Gy in 25 daily fractions for 5 weeks; for the patients with epithelial cell type or mixed type, the dose was 60 Gy in 30 daily fractions for 6 weeks. The survival rates were estimated by the Kaplan-Meier method. RESULTS: There was no recurrence and metastasis in either group. No acute and late radiological injuries were found among the patients receiving radiotherapy postoperatively. The 5-year and 10-year survivals were both 92% for the patients treated by surgery alone. However, the survival rates for patients who received radiotherapy were both 88%. There was no difference in the survivals in these two groups. Of the 3 died patients, 1 died of myasthenia gravis and 2 of intercurrent illness. No significant correlation was found between myasthenia gravis and radiotherapy. CONCLUSIONS: Postoperative radiotherapy is unnecessary for the patients with stage I thymoma. No relation is found between radiotherapy and myasthenia gravis.

Adult↗