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Biomedical subjects

M Yao

Publications and source records attributed to M Yao.

At least 109 records · Page 6Linked to original sources
PubMed1999

N-acetylglucosaminyltransferase V activity in metastatic models of human hepatocellular carcinoma in nude mice.

N-linked beta 1-6 branched oligosaccharides may contribute directly to the malignant phenotype including metastatic potential of tumour cells. Increased beta 1-6 branching was associated with an increased level of N-acetylglucosaminyltransferase V (GnT V). In this report, the tissues from two metastatic models of human hepatocellular carcinoma (HCC) in nude mice were obtained. GnT V activity and mRNA level were determined. Results showed that GnT V activity in highly metastatic LCI-D20 models (Liver Cancer Institute, passage time: 20 days) (413.1+/-86.4U) was much higher than that in low metastatic LCI-D35 model (passage time 35 days) (155.3+/-31.9U). Northern blot showed that the mRNA level of GnT V in two models had no change. During the selection of a highly metastatic LCI-D20 model, GnT V activity increased from 301.6+/-57.3U to 413.1+/-86.4U while the highly metastatic LCI-D20 model acquired higher metastatic ability after selection. When highly metastatic LCI-D20 model tissues were implanted subcutaneously (s.c.), the GnT V activity decreased dramatically from 413.1+/-86.4U to 94.9U. This is the first report that GnT V activity increased in HCC during metastasis in vivo.

Animals↗
PubMed1999

[Gene expression of growth factors and their receptors in healing of partial thickness burn wound in rats].

OBJECTIVE: To investigate the role of growth factors and their receptors in partial-thickness burn wound healing. METHODS: SD rats were used. After 10% total body surface area partial-thickness burn, wound tissues were harvested on postburn days (PBDs) 0(normal control), 1, 3, 5, 7, 10 and 14 respectively. The gene expressions of growth factors and their receptors were determined in wound by in situ hybridization and slot blotting hybridization. At the same time, the process of the wound healing was observed histologically, and the regeneration cycle of epidermal cells and the temporal change in inflammatory cells were measured. RESULTS: Inflammatory cells infiltrated into wound surface were neutrophils, followed by macrophages and lastly lymphocytes. Epidermal cells proliferated most actively on PBD 3 and the mitoses of them increased significantly on day 7 after burn. The gene expression of PDGF, PDGFR and EGFR reached peaks on PBD 1 and the gene expression of EGF and TGF beta-R2 were highest on PBD 3. In addition, the gene expression of TGF beta-R1 and TGF beta 1 increased significantly on PBDs 5 and 7 respectively. CONCLUSION: The data suggested that burn can induce gene expression of EGF, PDGF, TGF-beta 1 and their receptors temporally, spatially, and reversibility, which might play a major role in burn wound healing, and the mutual regulation may exist in the gene expression and the cell cycle.

Animals↗
PubMed1999

[Effect of anti-vascular endothelial growth factor antibody on the progression of human gastric cancer orthotopic xenotransplanted into nude mice].

OBJECTIVE: To study the inhibiting effect of anti-vascular endothelial growth factor (VEGF) on the growth and metastasis of gastric cancer. METHODS: The anti-tumor and anti-metastasis effect of anti-VEGF antibody, mitomycin C (MMC) were investigated by means of an orthotopic xenotransplanted model of human gastric cancer SGC-7901 in nude mice which had been randomly divided into 4 groups: control group receiving PBS, group receiving 50 microg/mice anti-VEGF antibody, group receiving 2 mg/kg MMC, and group receiving 50 microg/mice anti-VEGF antibody combined with 2 mg/kg MMC. Anti-VEGF antibody was given i.p. twice a week and MMC was administered i.p. once a week for 8 weeks from day 7 after transplantation. All animals were sacrificed at the end of 10 weeks. The tumor was weighted and the intra-tumoral microvessel density (MVD) was recorded, and the liver was histologically examined in order to discover micrometastasis. RESULTS: Both anti-VEGF antibody and MMC showed a significant inhibitory effect on the growth of primary tumors; in the combination treatment group the inhibitory effect was more significant than single agent. Liver metastasis developed in 19 of 28 mice (67.9%) of the controls and in 6 of 11 mice (54.5%) receiving MMC. In contrast, liver metastasis occurred in 2 of 10 mice (20%) receiving anti-VEGF antibody and none receiving combination treatment. In addition, the MVD was less significant in the anti-VEGF antibody group and combination treatment group than other groups. CONCLUSIONS: Anti-VEGF may provide a new approach to the treatment of gastric cancer by inhibiting tumor angiogenesis, and combination of anti-VEGF antibody with MMC could be more effective.

Animals↗
PubMed1999

[Experimental study of radiofrequency thermocoagulation and applied anatomy of posterior rami of lumbar nerves].

OBJECTIVE: To determine points of radiofrequency thermocoagulation of the posterior rami of the lumbar nerves and to choose an effective temperature at which the conduction of painful impulse can be blocked. METHODS: The posterior rami of the lumbar nerves were dissected in 15 corpses of adults. The ultrastructure of nerve fibres, changes of sensary conduction velocity (SCV) and the waveform of the unmedullated fibres which conduct painful impulse (c wave) were observed after the sciatic nerves of rabbits were coagulated at various temperatures (60 degrees C, 70 degrees C, 80 degrees C, 90 degrees C). RESULTS: "Transverse Process Root Area" and "Transverse Process Point" can be regarded as primary marks of thermocoagulation of the posterior rami of the lumbar nerves. Stimulation of square-wave can make the location more accurate. While the temperature of thermocoagulation reached 80 degrees C, none of painful afferent nerve fibres survived. CONCLUSIONS: With accurate location and good control of temperature, radiofrequency thermocoagulation will be an effective therapy for the patients suffering from pain resulted from pathological changes of the posterior rami of the lumbar nerves.

Adult↗
PubMed1999

[Effect of artemether on nucleoside uptake and nucleic acid content in Schistosoma japonicum].

AIM: To observe the effect of artemether (Art) on nucleoside uptake and nucleic acid content in Schistosoma japonicum. METHODS: RNA and DNA contents of both male and female worms harbored in mice treated intragastrically (i.g.) with Art 300 mg/kg for 24 h or 48 h were determined, respectively. After in vivo drug treatment, the schistosomes recovered were in vitro maintained in drug-free medium containing [3H]adenosine, [5-(3)H] uridine or [methyl-3H]thymidine at a final concentration of 37 MBq/L or 74 MBq/L for 2 h or 4 h, the tritiated nucleoside uptake and incorporation into nucleic acid of schistosomes were measured. RESULTS: The RNA and DNA contents of female worms recovered from the host 48 h after dosing were markedly decreased by 51.6% and 23.5%, respectively, while the RNA content of male worms showed 42.4% reduction. When the above-mentioned schistosomes were in vitro exposed to the tritiated nucleoside for 2 h or 4 h, apparent decrease in tritiated nucleoside uptake with reduction rates of 35.2%-50.1% was seen in female worms. The incorporation of [methyl-3H]thymidine into the female worm DNA 2 h after incubation was reduced by 71.4% while the incorporation of [3H]adenosine into the female worm RNA and DNA 4 h after incubation was reduced by 65.2% and 50.0%, respectively. CONCLUSION: Art exhibited an apparent effect on the nucleic acid metabolism in schistosomes, especially in female worms.

Animals↗
PubMed1998

Genomic structure and sequence of a human homologue (NTHL1/NTH1) of Escherichia coli endonuclease III with those of the adjacent parts of TSC2 and SLC9A3R2 genes.

Genomic cloning and sequencing of a human homologue (the gene name, endonuclease III-like 1; gene symbol, NTHL1 or NTH1) for Escherichia coli endonuclease III, that is involved in pyrimidine base excision repair, were performed. The sequence covered the entire NTHL1 gene consisting of six exons and five introns spanning 8kb with 5' flanking (8kb) and 3' flanking (3.8kb) regions. Southern blot analysis suggested that the NTHL1 gene exists as a single copy in a haploid genome. The sequenced 5' flanking region lacks typical TATA and CAAT boxes, but contains a CpG island having putative binding sites for several transcription factors such as Ets1 and Sp1. The NTHL1 gene lies immediately adjacent to the tuberous sclerosis 2 (TSC2) gene on chromosome 16p13.3 in a 5'-to-5' orientation. Transcription initiation sites of both NTHL1 and TSC2 genes were suggested to be multiple by 5' RACE experiments. The northern hybridization experiment suggested that both genes are expressed in all tissues, but at different levels. Downstream of the NTHL1 gene, the gene for the regulatory factor 2 (SLC9A3R2/E3KARP; also called OCTS2, TKA-1 and SIP-1) of the solute carrier family 9 (sodium/hydrogen exchanger), isoform A3, lies in a 3'-to-3' orientation. This paper demonstrates for the first time the spatial relationship of these three genes (TSC2, NTHL1 and SLC9A3R2) at the nucleotide level, and the presence of multiple transcription initiation sites of the NTHL1 and TSC2 genes.

Base Sequence↗
PubMed1998

Sensitive liquid chromatographic-mass spectrometric assay for the simultaneous quantitation of nefazodone and its metabolites hydroxynefazodone m-chlorophenylpiperazine and triazole-dione in human plasma using single-ion monitoring.

A sensitive, selective, accurate, precise and reproducible high-performance liquid chromatographic-mass spectrometric (LC-MS) assay was developed and validated for the simultaneous determination of nefazodone (NEF), hydroxynefazodone (OH-NEF), m-chlorophenylpiperazine (mCPP), and triazole-dione (Dione) in human plasma using trazodone (TRZ) as the internal standard (I.S.). The method involved simultaneous protein precipitation with acetonitrile and liquid-liquid extraction with methylene chloride, after which the organic layer was evaporated to dryness. The residue was reconstituted in 25% acetonitrile in 10 mM ammonium formate (pH 4.0), and an aliquot was injected onto a BDS Hypersil C18 column at a flow-rate of 0.3 ml/min. The mobile phase comprising of 10 mM ammonium formate (pH 4) and acetonitrile in 55:45 (v/v) was used in an isocratic condition. The mass spectrometer was programmed to admit the protonated molecules at m/z 197.0 (mCPP), 372.0 (I.S.) 470.4 (NEF), 458.1 (Dione), and 486.2 (OH-NEF). Standard curves were linear (r2 > or = 0.995) over the concentration range of 4-1000 ng/ml for Dione and 2-500 ng/ml for other analytes. The lowest standard concentrations were the lower limit of quantitation for each analyte. The mean predicted quality control (QC) concentrations for all analytes deviated less than -12.1% from the corresponding nominal values; the intra-assay and inter-assay precision of the assay for all analytes were within 7.0% relative standard deviation. All analytes including I.S. were stable in the injection solvent at room temperature for at least 24 h. The extraction recovery of the various analytes ranged from 67.3 to 86.5%. The validated assay was applied to a pharmacokinetic study of nefazodone.

Antidepressive Agents, Second-Generation↗
PubMed1998

High alkaline phosphatase activity in 3p-induced human renal cancer cells.

Recent studies have suggested that a tumor suppressor gene is located on the short arm of chromosome 3 (3p) for tumorigenesis of sporadic renal cell carcinoma. In this study, we introduced 3p from normal human fibroblasts into the renal cancer cell line YCR and this introduction clearly resulted in inhibited growth in vitro and in vivo. Furthermore, we investigated several enzyme activities of original YCR cells and 3p-induced clones (YCR-151 and YCR-152) and found that only alkaline phosphatase activity in 3p-induced clones was significantly increased compared to that of the original YCR cells.

Alkaline Phosphatase↗
PubMed1998

Redox-coupled crystal structural changes in bovine heart cytochrome c oxidase.

Crystal structures of bovine heart cytochrome c oxidase in the fully oxidized, fully reduced, azide-bound, and carbon monoxide-bound states were determined at 2.30, 2.35, 2.9, and 2.8 angstrom resolution, respectively. An aspartate residue apart from the O2 reduction site exchanges its effective accessibility to the matrix aqueous phase for one to the cytosolic phase concomitantly with a significant decrease in the pK of its carboxyl group, on reduction of the metal sites. The movement indicates the aspartate as the proton pumping site. A tyrosine acidified by a covalently linked imidazole nitrogen is a possible proton donor for the O2 reduction by the enzyme.

Animals↗
PubMed1998

ID14 'Quadriga', a Beamline for Protein Crystallography at the ESRF.

The ESRF undulator beamline ID14 'Quadriga' is dedicated to monochromatic macromolecular crystallography. Using two undulators with 23 mm and 42 mm periods and a minimum gap of 16 mm installed on a high-beta section, it will provide high-brilliance X-ray beams at around 13.5 keV, as well as a wide tuneability between 6.8 and 40 keV. Based on the Troika concept, this beamline has four simultaneously operating experimental stations: three side stations, EH1, EH2 and EH3, using thin diamond crystals, and an end station, EH4, with a fast-scan double-crystal monochromator. Station EH3 has a kappa-diffractometer, and an off-line Weissenberg camera with a large 80 x 80 cm active area combined with a 2048 x 2048 CCD detector. During data collection the image plates are placed and removed by a robot located inside the hutch using a cassette system. After data collection the image plates are scanned with an off-line drum scanner. Station EH4 is designed for MAD applications, including Xe K-edge anomalous experiments, and is equipped with a 2048 x 2048 CCD detector on a pseudo 2theta arm. A common graphical user interface and a database will be available to cover all aspects of data collection, including strategy optimization. First results on the performance of the optics elements and initial crystallographic results are presented.

Journal Article↗
PubMed1998

Alterations in the expression of P2X1 receptors in failing and nondiseased human atria.

This is the first report of the analysis of the ATP-specific P2X1 receptor subunit in human hearts. We have examined homogenate samples of human left atria for the presence of P2X1 receptors using Western blots. Anti-P2X1 immunoreactivity was detected in populations of nondiseased atria as well as in atria from explanted hearts from patients with terminally failing heart conditions such as dilated cardiomyopathy. At least three groups of P2X1 immunoreactive proteins were detected in the Western blots with approximate molecular mass values of 50, 70, and 160 kDa. We report changes in expression of their 50 and 70 kDa components. These changes may be related to the type of deficit in these hearts since the changes have been observed in hearts with decreased ejection fractions characteristic of dilated cardiomyopathy.

Animals↗
PubMed1998

Elevated activity of N-acetylglucosaminyltransferase V in human hepatocellular carcinoma.

Cell-surface glycoproteins are regarded as candidates for involvement in the spread of tumor cells. N-linked beta1-6 branched oligosaccharides may contribute directly to the malignant or metastatic phenotypes of tumor cells. Increased beta1-6 branching has been associated with an increased level of N-acetylglucosaminyltransferase V (GlcNAc transferase V), the glycosyltransferase that initiates the beta1-6 branching. In this report, 33 pathologically verified hepatocellular carcinoma (HCC) specimens, six non-cancerous tissues surrounding HCC and five normal liver specimens have been studied. We have quantified N-linked beta1-6 branched oligosaccharides indirectly by measuring GlcNac transferase V activity. The average GlcNac transferase V activities in hepatocellular carcinoma (HCC), noncancerous tissues surrounding HCC and normal liver tissues were 324.2 +/- 269.8, 84.8 +/- 20.7 and 7.0 +/- 6.2 pmol product h(-1) mg protein(-1) (P < 0.05) respectively. In addition, the activity was correlated with the TNM classification of HCC. The average activities of GlcNAc transferase V in stages T1, T2-3 and T4 were 77.6 +/- 57.8, 369.0 +/- 294.7 and 329.9 +/- 205.9 pmol product h(-1) mg protein h(-1) respectively (P < 0.05), showing that the activity of the enzyme in advanced HCC was higher than that in early HCC. Our preliminary results indicated that GlcNAc transferase V activity increased in human HCC and was correlated with its progression.

Adult↗
PubMed1998

Quantitative and qualitative alterations of long-term culture-initiating cells in patients with acute leukaemia in complete remission.

Bone marrow (BM) samples from 24 patients with acute leukaemia (AML 17, ALL seven) in first complete remission were compared to samples from 10 normal donors with regard to their content in long-term culture-initiating cells (LTC-IC) as assessed by a limiting dilution assay and the clonogeneic capacity of these cells, in order to determine whether remission marrow cells displayed any specific defect at the primitive stem cell level. The frequency of LTC-IC in the whole patient group was 1 in 3487 +/- 3125 mononuclear cells (MNC) as compared to 1 in 794 +/- 492 MNC in normal controls (P = 0.0009), with no difference between AML and ALL. Moreover, the clonogeneic capacities were 2.66 +/- 0.7 (range 1.8-1.6) and 4.0 +/- 1.6 (range 2.2-7.9) CFC per LTC-IC in patients and controls respectively (P = 0.0015). These quantitative and qualitative defects were aggravated by treatment with mafosfamide at a dose of 50 microg/10(7) MNC/ml, where the mean recovery of LTC-IC after in vitro purging was 42%. In nine patients autografted with purged marrow following high-dose radiochemotherapy, no correlation could be detected between the dose of LTC-IC (mean 6742 +/- 7877/kg) and the kinetics of recovery of haemopoiesis. We concluded that, in acute leukaemia patients in complete remission, the presumably normal residual stem cell pool was not only quantitatively diminished but also qualitatively altered in its capacity to give rise to clonogeneic progenitor cells.

Acute Disease↗
PubMed1998

Surgical and medical management of tubal and non-tubal ectopic pregnancies.

This article highlights recent findings in the diagnosis and management of ectopic pregnancy. While the search for the ideal biochemical marker for ectopic pregnancy continues, new protocols have been described for the management of persistent ectopic pregnancy. The role of nuclear marker Ki-67 in trophoblastic proliferation and the only randomized trial to date involving systemic methotrexate and laparoscopic surgery are discussed. The management of cervical, interstitial and heterotopic pregnancies are reviewed.

Female↗
PubMed1998

Cephalometric parameters after multilevel pharyngeal surgery for patients with obstructive sleep apnea.

Cephalometric studies have shown narrowing in the upper airway at multiple levels in patients with obstructive sleep apnea. Uvulopalatopharyngoplasty (UPPP), mandibular osteotomy with genioglossus advancement, and hyoid myotomy with advancement address narrowing in the retropalatal and retrolingual regions. In an effort to relate postoperative clinical changes to anatomic changes, cephalometric studies were performed on 44 patients who underwent multilevel pharyngeal surgery (UPPP, genioglossus advancement, hyoid myotomy with advancement). Both pre- and postoperative radiographs were available for 23 of these patients. The posterior airway space (P = .09), minimal posterior airway space (P = .04), posterior uvular space (P = .06), mandibular plane-to-hyoid distance (MP-H) (P = .06) and central incisor-to-tongue base distance (P = .02) all improved after surgery. None of the measurements of the posterior airway were significantly different between responders and nonresponders. The degree of collapse of the palate on modified Müller maneuver was highly correlated with the severity of sleep apnea as measured by the respiratory disturbance index; the collapse of the lateral pharyngeal walls was moderately correlated; and collapse of the base of tongue was not correlated. Cephalometric radiographs may reflect the anatomic changes that result from upper airway surgery for sleep apnea, but these changes are not useful for assessing surgical efficacy. The modified Müller maneuver, however, may represent a more predictive evaluation.

Adult↗
PubMed1998

A longitudinal, functional study of peripheral nerve recovery in the mouse.

OBJECTIVES: To verify the validity of the recently described sciatic functional index for mice to monitor neuronal functional recovery over time using a blinded, randomized, and controlled evaluation. STUDY DESIGN: Surgery was performed on the left sciatic nerves of 62 C57/BL mice after randomly assigning them to one of four surgical groups: sham surgery, sciatic nerve crush, nerve transection without repair, and nerve transection followed by epineurial suture repair. Sciatic functional indices were measured before surgery and then after surgery at 10-day intervals for 90 days, using a previously described formula. RESULTS: Sham surgery did not affect nerve function when compared with preoperative values (P > .24). Crush surgery produced a reversible nerve injury that fully recovered after 20 days. Nerve transection without repair resulted in complete functional disability without recovery of function during the 90-day follow-up interval. When transected nerves were repaired, complete functional disability was noted at day 10, with subsequent functional recovery to 26% of function at day 30. This level of recovery persisted until the 60th postoperative day when muscle contractures resulted in progressive worsening of the index. There were statistically significant differences between the sciatic functional indices of each of the groups (P < .05). CONCLUSIONS: The previously described sciatic functional index for mice is an accurate indicator of the level of sciatic neuronal function during recovery. This index represents a method of evaluating neuronal function that may provide a better reflection of the recovery parameters that are important in clinical situations. The sciatic functional index will allow for study of sciatic nerve functional recovery in genetically engineered transgenic mice.

Animals↗
PubMed1998

[Analysis of the prognostic factor in the patients with locally invasive bladder cancer who underwent total cystectomy].

OBJECTIVES: Prognosis and related factors were analysed as for the patients with locally invasive bladder cancer who underwent total cystectomy and pelvic lymph node dissection. METHODS: Between January 1977 and December 1996, a hundred and one patients with locally invasive bladder cancer underwent total cystectomy and pelvic lymph node dissection at University Hospital. Survival rates of these patients were calculated by Kaplan-Meier method and statistical significances were analysed by univariate and multivariate analyses. RESULTS: Most significant factor was PS at cystectomy and pN was next. Survival rate of the patients who underwent total cystectomy after 1988 showed significantly better than others. Thirteen patients achieved complete response by preoperative therapy. But, two of them who had positive nodes were died by cancer. CONCLUSION: Considering from these results, performance status at cystectomy and lymph node metastasis are predictable prognostic factor for locally invasive bladder cancer patients.

Adult↗