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Biomedical subjects

W Song

Publications and source records attributed to W Song.

At least 73 records · Page 4Linked to original sources
PubMed2000

Expression of bone morphogenetic protein receptors type-IA, -IB and -II correlates with tumor grade in human prostate cancer tissues.

Bone morphogenetic proteins (BMPs) are potential regulators of prostate cancer cell growth and metastasis that signal through an interaction with BMP membrane receptors (BMPRs) type I and type II. In the present study, Western blot and immunohistochemical analysis of BMPRs were carried out in benign and malignant human prostate tissues to explain the loss of BMP response in human prostate cancer cells. The results demonstrated that the benign prostate specimens expressed high levels of all three BMPRs. In normal prostate, BMPRs were localized predominantly to epithelial cells. Among prostate cancer specimens, well-differentiated cancers were positive for the expression of BMPR-II, BMPR-IA, and BMPR-IB, for the most part. In contrast, only 1 of 10 poorly differentiated prostate cancer cases was positive for each of the three BMPRs (P < 0.005 for all three receptors). Taken together, these results indicate that human prostate cancer cells frequently exhibit loss of expression of BMPRs and suggest that loss of BMPRs may play an important role during the progression of prostate cancer.

Blotting, Western↗
PubMed2000

[Effects of glycidyl methacrylate on gap junctional intercellular communication].

In order to probe into the mechanism of glycidyl methacrylate (GMA)-induced cell transformation, the effects of GMA on gap junctional intercellular communication (GJIC) in human lung, embryonic fibroblasts(HLEF) were studied by using scrape-loading and dye transfer(SLDT) technique. HLEF cells were treated with GMA at concentrations of 0.5, 2.5 and 5.0 mg/L for 12 hours and Lucifer Yellow was introduced by scrape-loading after exposure. The GJIC in exposed cells and that of control were determined directly as the diffusion extent of fluorescent dye into adjacent cells. The results indicated that GMA could inhibit the GJIC in exposed cells in a dose-dependent manner. Significantly decreased GJIC was found in 2.5 and 5.0 mg/L dose groups. It was suggested that the inhibition of GJIC might be one of the mechanisms responsible for GMA-induced cell transformation.

Cell Communication↗
PubMed2000

Role of lipooligosaccharide in Opa-independent invasion of Neisseria gonorrhoeae into human epithelial cells.

Lipooligosaccharide (LOS) has been implicated in the adhesion and invasion of host epithelial cells. We examined the adhesive and invasive abilities of isogenic gonococcal opacity-associated outer membrane protein-negative, pilus-positive (Opa-Pil+) Neisseria gonorrhoeae strains expressing genetically defined LOS. Strain F62 (Opa-Pil+), expressing the lacto-N-neotetraose and the galNac-lacto-N-neotetraose LOS, and its isogenic derivative that expressed only the lacto-N-neotetraose LOS (F62 Delta lgtD), adhered to, and invaded, to the same extent the human cervical epidermoid carcinoma cell line, ME180. While the adhesive abilities of Opa-Pil+ isogenic strains that express LOS molecules lacking the lacto-N-neotetraose structure were similar to that seen for F62, their invasive abilities were much lower than the strains expressing lacto-N-neotetraose. Fluorescence microscopy studies showed that the adherence of F62, but not the strains lacking lacto-N-neotetraose, induced the rearrangement of actin filaments under the adherent sites. Electron microscopy studies demonstrated that F62, but not the strains lacking lacto-N-neotetraose, formed extensive and intimate associations with epithelial cell membranes. Thus, in the absence of detectable Opa protein, the lacto-N-neotetraose LOS promotes gonococcal invasion into ME180 cells. The data also suggest that LOS is involved in the mobilization of actin filaments in host cells, and in the formation of a direct interaction between the bacterial outer membrane and the plasma membrane of ME180 cells.

Actins↗
PubMed2000

Role of Sec61alpha in the regulated transfer of the ribosome-nascent chain complex from the signal recognition particle to the translocation channel.

Targeting of ribosome-nascent chain complexes to the translocon in the endoplasmic reticulum is mediated by the concerted action of the signal recognition particle (SRP) and the SRP receptor (SR). Ribosome-stripped microsomes were digested with proteases to sever cytoplasmic domains of SRalpha, SRbeta, TRAM, and the Sec61 complex. We characterized protein translocation intermediates that accumulate when Sec61alpha or SRbeta is inactivated by proteolysis. In the absence of a functional Sec61 complex, dissociation of SRP54 from the signal sequence is blocked. Experiments using SR proteoliposomes confirmed the assembly of a membrane-bound posttargeting intermediate. These results strongly suggest that the Sec61 complex regulates the GTP hydrolysis cycle of the SRP-SR complex at the stage of signal sequence dissociation from SRP54.

Animals↗
PubMed2000

A precursor form of prostate-specific antigen is more highly elevated in prostate cancer compared with benign transition zone prostate tissue.

Prostate-specific antigen (PSA) is a widely used serum marker for prostate cancer (PCa), but in the critical diagnostic range of 4-10 ng/ml it has limited specificity for distinguishing early PCa from benign prostatic hyperplasia (BPH). PSA in serum is comprised of a variety of both "free" and "complexed" forms that have been used to improve the specificity of PSA for prostate cancer detection. We previously reported that pro PSA (pPSA), the zymogen or precursor form of PSA, is a component of free PSA in the serum of PCa patients. In the current study, we examined prostate tissues to understand the origin and specificity of pPSA. PSA was immuno-affinity purified from matched sets of prostate tissues including peripheral zone cancer (PZ-C); peripheral zone noncancer; and benign tissue from the transition zone (TZ), the primary site of BPH within the prostate. We found that pPSA is differentially elevated in PZ-C, but is largely undetectable in TZ. N-terminal sequencing revealed that the pPSA was comprised primarily of [-2]pPSA and minor levels of [-4]pPSA, containing pro leader peptides of 2 and 4 amino acids, respectively. The median value of pPSA was 3% in PZ-C and 0% (undetectable) in TZ (P < 0.0026). No pPSA was detected in 13 of 18 transition zone specimens (72%), but only 2 of the 18 matched cancer specimens (11%) contained no measurable pPSA. These results demonstrate that pPSA is more highly correlated with prostate cancer than with BPH. The pPSA in serum may represent a more cancer-specific form of PSA that could help distinguish prostate cancer from BPH.

Humans↗
PubMed2000

Tumor necrosis factor-alpha induces apoptosis via inducible nitric oxide synthase in neonatal mouse cardiomyocytes.

OBJECTIVE: It has been demonstrated that tumor necrosis factor-alpha (TNF alpha) induces apoptosis in cardiac myocytes. However, its mechanism of action is still not well understood. In the present study, we hypothesized that TNF alpha induces myocardial apoptosis by induction of inducible nitric oxide synthase (iNOS). METHODS: Neonatal cardiac myocytes were isolated from iNOS (-/-) mutant and C57BL6 wild type mice. Cells were cultured for 3 days before treatment with an NO donor or TNF alpha. Following treatment with S-nitroso-N-acetyl-penicillamine (SNAP) or TNF-alpha, cells were tested for apoptosis by terminal deoxynucleotidyl transfer-mediated end labeling (TUNEL) staining and cell death detection ELISA. NO production was measured by nitrite concentration in the culture medium. Cardiomyocyte expression of iNOS and TNF type 1 receptor (TNFR1) mRNA was determined by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: SNAP (0.01-100 microM) induced apoptosis of cardiac myocytes in a concentration-dependent manner in the wild type mice (n = 5, P < 0.01). TNFR1 mRNA was expressed in neonatal cardiomyocytes from both wild type and iNOS (-/-) mutant mice. TNF alpha induced a concentration-dependent increase in iNOS mRNA expression and nitrite production as well as significant apoptosis of cardiomyocytes in the wild type mice (n = 4, P < 0.01). However, without iNOS expression, the apoptotic effects of TNF-alpha were significantly attenuated in cardiomyocytes from iNOS (-/-) mutant mice (n = 4, P < 0.05). CONCLUSION: TNF alpha induces apoptosis via iNOS expression and NO production in neonatal mouse cardiomyocytes.

Analysis of Variance↗
PubMed2000

"BPSA," a specific molecular form of free prostate-specific antigen, is found predominantly in the transition zone of patients with nodular benign prostatic hyperplasia.

OBJECTIVES: The biologic mechanism for the increased proportion of noncomplexed ("free") prostate-specific antigen (PSA) found in the serum of patients with benign prostate disease is unknown. We recently reported that most of the PSA found in benign, hyperplastic, and cancerous prostatic tissue is in the free form. To determine whether specific molecular forms of free PSA are associated differentially with normal, hyperplastic, or cancerous prostatic tissue, we have further characterized the free PSA in each type of prostatic tissue. METHODS: PSA was purified by immunoaffinity chromatography from matched prostatic tissue samples of peripheral zone cancer (PZ-C), PZ noncancer (PZ-N), and transition zone (TZ) tissue from 10 large-volume (greater than 50 g) and 8 small-volume (less than 25 g) radical prostatectomy specimens. Eight TZ specimens obtained during transurethral resection of the prostate for benign prostatic hyperplasia (BPH) were also analyzed. The different molecular forms of PSA were further resolved by high-performance hydrophobic interaction chromatography. Clipped forms of PSA were identified by N-terminal amino acid sequencing. RESULTS: More than 99% of the PSA in prostatic tissues was in the free, noncomplexed form. Specimens from the prostate TZ were found to contain elevated levels of an altered form of PSA, which we designated BPSA. Purified BPSA contained a distinctive cleavage at lysine 182. The median percent BPSA (%BPSA) was 11.4 in the TZ of specimens with nodular BPH compared with a %BPSA of 4.1 in the TZ of specimens without nodular BPH (P <0.0014). The median %BPSA levels of the PZ-N and PZ-C tissues ranged from 3.2 to 4.9 and were not significantly different from one another or from the %BPSA level of TZ tissues without nodular BPH. CONCLUSIONS: We have identified a specific molecular form of clipped free PSA, called BPSA, that is increased within the prostatic TZ of patients exhibiting nodular BPH. Higher levels of percent free PSA in serum have been found to correlate strongly with prostate volume, which in turn is closely associated with the progressive enlargement of nodular BPH tissue within the TZ of the prostate. Thus, it is possible that a proportion of the serum percent free PSA found in patients with BPH may be composed of BPSA released into the serum.

Humans↗
PubMed2000

Observations on trichodinid ectoparasites (Ciliophora: Peritricha) from the gills of maricultured molluscs in China, with descriptions of three new species of Trichodina Ehrenberg, 1838.

During surveys of the trichodinid parasites in mariculture beds off the coast of Shandong Province, China, four species of the genus Trichodina from the gills of marine molluscs were investigated and morphologically studied. Of these, three are described as new: T. ruditapicis n. sp. from Ruditapes philippinarum (Veneridae), T. scapharcae n. sp. from Scapharca subcrenata (Arcidae) and T. mactrae n. sp. from Mactra veneriformis (Mactridae). One little-known species, T. macomarum Raabe & Raabe, 1959, is redescribed from M. veneriformis. Taxonomic and morphometric data for these trichodinids based on wet silver nitrate and protargol-impregnated specimens are presented. For each of the new species, comparisons with closely related species are provided.

Animals↗
PubMed2000

Efficient DNA transfection in neuronal and astrocytic cell lines.

We have studied different parameters for efficient DNA transfection in various cell types and with different size of the promoter. Here we report that the optimum condition for DNA transfection by electroporation is 350 V/960 microF for PC12, 450V/960 microF C6 cells, and 250 V/500 microF for COS-1 cells. For the human neuroblastoma (SK-N-SH) cells the optimum condition for DNA transfection is by the calcium phosphate method. In promoter mapping studies, a serial deletion approach is commonly used. To optimize transfection we have selected three DNA constructs that varied in size from 4.5 to 12.4 kilobases (kb). We measured the promoter activity of these constructs under conditions of 'equal amount', 'equimolar', and 'equimolar plus carrier DNA to make it equal amount'. We recommend that for comparative purpose, transfection should be carried out under 'equimolar condition' without a need to adjust the total amount of DNA by carrier DNA. Taken together, our results suggest that efficient methods for DNA transfection are important to study gene regulation by devising better ways to deliver DNA into the mammalian cells.

Amyloid beta-Protein Precursor↗
PubMed2000

Persistent, antigen-specific, therapeutic antitumor immunity by dendritic cells genetically modified with an adenoviral vector to express a model tumor antigen.

Dendritic cells (DC) are potent antigen-presenting cells that play a critical role in the initiation of cellular immune responses. Using a BALB/c syngeneic colon carcinoma cell line expressing a model tumor antigen beta-galactosidase (betagal), we previously reported (Song et al, J Exp Med 1997; 186: 1247-1256) that immunization of mice with a single injection of DCs genetically modified with an adenovirus vector expressing betagal confers potent protection against a lethal intravenous tumor challenge, as well as suppression of pre-established lung tumors, resulting in a significant survival advantage. In the present study, we have addressed the question: how long does the memory of tumor antigen- specific immunity persists after DC priming in vivo using this genetically modified DC-based cancer vaccination strategy? To accomplish this, two groups of mice were evaluated: (1) mice surviving >400 days following protection from an initial intravenous tumor challenge after immunization with DC genetically modified to express betagal; and (2) mice surviving >300 days that had previously demonstrated regression of pre-established lung tumors after treatment with DC immunization. By analyzing the antigen-specific cytotoxic T lymphocyte response and challenging these long-term survival mice with a second subcutaneous tumor administration, the data demonstrate that a single administration of DC genetically modified to express a model antigen induces long-lasting, antigen-specific antitumor immunity in both naive and tumor-bearing hosts, observations that have important implications in the development of genetically modified DC-based antitumor vaccination strategies. Gene Therapy (2000) 7, 2080-2086.

Adenoviridae↗
PubMed2000

Effects of a high-fat-sucrose diet on enzymes in homocysteine metabolism in the rat.

Hyperhomocysteinemia (HH) and hyperinsulinemia are both risk factors for cardiovascular disease. To examine the effects of hyperinsulinemia on homocysteine metabolism, we fed rats a high-fat-sucrose (HFS) diet and then measured the hepatic mRNA and activity of 2 key enzymes involved in this metabolic pathway: 5,10-methylenetetrahydrofolate reductase (MTHFR) and cystathionine-beta-synthase (CbetaS). Fischer rats made insulin-resistant by a HFS diet were examined at 6 months and 2 years of age and compared with control rats fed a low-fat, complex-carbohydrate (LFCC) diet. At the end of 6 months, the HFS rats were heavier than the LFCC rats (214 +/- 3.4 v 188 +/- 1.4 g, P < .01). There were no differences in blood glucose between HFS and LFCC rats; however, plasma insulin and homocysteine concentrations were elevated in HFS rats (insulin, 56 +/- 12 v 14.5 +/- 2.9 microU/mL; homocysteine, 10.77 +/- 0.9 v 6.89 +/- 0.34 micromol/L, P < .01). Hepatic CbetaS enzyme activity was significantly lower in HFS compared with LFCC rats (0.45 v 0.64 U/mg, P = .0001), and this decrease was reflected in a decrease of the CbetaS mRNA concentration. In contrast, hepatic MTHFR enzyme activity and mRNA concentration were significantly elevated in the HFS group compared with controls (HFS and LFCC, 8.62 and 4.8 nmol/h/mg protein, respectively, P = .0001). These changes in plasma homocysteine, CbetaS, and MTHFR were significantly correlated with the degree of obesity and hyperinsulinemia. Fasting plasma insulin correlated significantly and positively with plasma homocysteine (r = .51, P < .01) and MTHFR activity (r = .48, P < .01) and negatively with CbetaS activity (r = -.54, P < .001). CbetaS and MTHFR activities were inversely correlated with each other (r = -.58, P < .001). In conclusion, rats fed a HFS diet are hyperinsulinemic, and the hyperinsulinemia is associated with an elevated homocysteine concentration and changes in 2 key enzymes in homocysteine metabolism.

Age Factors↗
PubMed2000

Epidermal growth factor receptor agonists increase expression of glutamate transporter GLT-1 in astrocytes through pathways dependent on phosphatidylinositol 3-kinase and transcription factor NF-kappaB.

The glial glutamate transporter GLT-1 may be the predominant Na(+)-dependent glutamate transporter in forebrain. Expression of GLT-1 correlates with astrocyte maturation in vivo and increases during synaptogenesis. In astrocyte cultures, GLT-1 expression parallels differentiation induced by cAMP analogs or by coculturing with neurons. Molecule(s) secreted by neuronal cultures contribute to this induction of GLT-1, but little is known about the signaling pathways mediating this regulation. In the present study, we determined whether growth factors previously implicated in astrocyte differentiation regulate GLT-1 expression. Of the six growth factors tested, two [epidermal growth factor (EGF) and transforming growth factor-alpha] induced expression of GLT-1 protein in cultured astrocytes. Induction of GLT-1 protein was accompanied by an increase in mRNA and in the V(max) for Na(+)-dependent glutamate transport activity. The effects of dibutyryl-cAMP and EGF were additive but were independently blocked by inhibitors of protein kinase A or protein tyrosine kinases, respectively. The induction of GLT-1 in both EGF- and dibutyryl-cAMP-treated astrocytes was blocked by inhibitors targeting phosphatidylinositol 3-kinase (PI3K) or the nuclear transcription factor-kappaB. Furthermore, transient transfection of astrocyte cultures with a constitutively active PI3K construct was sufficient to induce expression of GLT-1. These data suggest that independent but converging pathways mediate expression of GLT-1. Although an EGF receptor-specific antagonist did not block the effects of neuron-conditioned medium, the induction of GLT-1 by neuron-conditioned medium was completely abolished by inhibition of PI3K or nuclear factor-kappaB. EGF also increased expression of GLT-1 in spinal cord organotypic cultures. Together, these data suggest that activation of specific signaling pathways with EGF-like molecules may provide a novel approach for limiting excitotoxic brain injury.

ATP-Binding Cassette Transporters↗
PubMed2000

[A quantitative analysis of IL-6 mRNA expression of peripheral blood monocyte cell in patients with chronic hepatitis B].

OBJECTIVE: To investigate the relationship of interleukin-6 (IL-6) mRNA expression with the immunopathogenesis and viral clearance. METHODS: The serum IL-6 level of patients with chronic hepatitis B (CHB) were detected by ELISA and quantitatively the IL-6 mRNA expression of peripheral blood monocyte cell (PBMC) in patients with CHB were analysed by competitive RT-PCR-ELISA. RESULTS: Serum level of IL-6 in patients with CHB was significantly increased. Both expression rates of IL-6 mRNA target fragment in control and in patients with CHB were 41.7% (5/12) and 82.1% (23/28) respectively. The quantitative ELISA of production of RT-PCR showed the copies of IL-6 mRNA in 5 cases of control were 1 000 to 10 000 (the mean log copies was 3.65), while the copies of IL-6 mRNA in 23 cases of patients were all more then 10 000 (the mean log copies was 4.40). CONCLUSION: This study shows that the increased level of IL-6 may play some role in hepatitis B infection, the increased serum level of IL-6 is related to the enhanced expression of IL-6 mRNA of PBMC.

Adult↗
PubMed2000

Protective effects of bilobalide on amyloid beta-peptide 25-35-induced PC12 cell cytotoxicity.

AIM: To study the effect of bilobalide, a terpene extracted from the leaves of Ginkgo biloba, on beta-amyloid peptide fragment 25-35 (A beta 25-35)-induced PC12 cell cytotoxicity. METHODS: 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assay were used to measure the viability of PC12 cells. Thiobarbituric acid-reactive substances were measured to determine lipid peroxidation of cells. Antioxidant enzymes in PC12 cells were detected. RESULTS: Treatment of PC12 cells with A beta 25-35 (100 mumol.L-1) for 24 h caused a great decrease in cell viability (P < 0.01 compared with control). Bilobalide 25-100 mumol.L-1 dose-dependently attenuated the cytotoxic effect of A beta 25-35. Bilobalide also inhibited A beta 25-35 (100 mumol.L-1)-induced elevation of lipid peroxidation and decline of antioxidant enzyme activities. CONCLUSION: Bilobalide protected PC12 cells from A beta 25-35-induced cytotoxicity.

Amyloid beta-Peptides↗
PubMed2000

[Abdominoplasty with a combined technique of lipectomy and liposuction].

OBJECTIVE: To evaluate an abdominoplasty technique combined with lipectomy and liposuction. METHODS: Twenty-five patients were undergoing for the abdominoplasty with lipectomy and liposuction in the same operation procedure. A public incision with W-shape was used for the lower abdominal lipectomy, and the upper abdomen was treated with an electronic liposuction technique. After the operation, each patient was followed up for evaluation of the results. RESULT: All of the patients got good contour of the abdomen without obvious complications. The abdominal perimeter was shrunk form 5 cm to 15 cm with over 3 months follow-ups. CONCLUSIONS: The combination of lipectomy and liposuction may be a good and safe method for abdominoplasty. The abdominal flap during the lipectomy could achieve higher survival rate than the traditional technique, due to the less injury on the neurovascular structures sustained by the liposuction procedure.

Abdominal Muscles↗
PubMed2000

Protective effect of bilobalide against nitric oxide-induced neurotoxicity in PC12 cells.

AIM: To examine the effects of bilobalide on nitric oxide-induced neurotoxicity in pheochromocytoma-derived PC12 cells (PC12 cells). METHODS: PC12 cell survival was monitored by LDH release and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assays. Superoxide dismutases (SOD) and catalase (CAT) activities were measured based on their abilities to inhibit the oxidation of epinephrine by the xanthine-xanthine oxidase system or to decompose H2O2 respectively. The content of malondialdehyde (MDA) was measured by a fluorometric assay to indicate the lipid peroxidation. RESULTS: 3-Morpholinosydnonimine (SIN-1, 50-300 mumol.L-1) induced PC12 cell damage. After the cells had been pretreated with 10 mumol.L-1 bilobalide for 24 h, the cell viability was increased to 91% +/- 30% from 52% +/- 14% in SIN-1 alone group. Moreover, the activities of SOD and CAT were increased after cells were treated with bilobalide. CONCLUSION: The NO-induced neurotoxicity can be protected by bilobalide in PC12 cells. The bilobalide-induced increase in SOD and CAT activities may serve as one of the mechanisms underlying the neuroprotective effect of bilobalide.

Animals↗
PubMed2000

Amyloid-beta 25-35 peptide induces expression of monoamine oxidase B in cultured rat astrocytes.

AIM: To investigate the effects of amyloid-beta 25-35 peptide (A beta 25-35) on monoamine oxidase (MAO) expression and activity in primary cultured rat astrocytes. METHODS: Immunocytochemistry was used to observe the morphological changes in astrocytes. Fluorescence spectrophotometry was used to measure the activity of MAO in astrocytes. The expression of MAO in astrocytes was assayed by RT-PCR. RESULTS: A beta 25-35 induced a reactive morphological change in cultured rat astrocytes which was accompanied by increased immunoreactivities for glial fibrillary acidic protein. Treatment with A beta 25-35 resulted in an elevation of MAO activity in a dose- and time-dependent manner. A beta 25-35-induced enhancement of MAO activity was of type B (MAO-B). The increase in MAO-B activity appeared to be due to an increase in the number of enzyme molecules since kinetic analysis demonstrated a 1.5 fold increase in Vmax with no change in Km. Treatment with A beta 25-35 also led to a substantial increase in MAO-B mRNA level in the astrocytes. CONCLUSION: A beta 25-35 is able to selectively induce MAO-B expression in rat astrocytes and that the upregulation of MAO-B in A beta 25-35-stimulated astrocytes may play an important role in the pathogenesis of Alzheimer's disease.

Amyloid beta-Peptides↗