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Biomedical subjects

S Ye

Publications and source records attributed to S Ye.

At least 109 records · Page 6Linked to original sources
PubMed1998

Targeted gene correction: a new strategy for molecular medicine.

Advances, over the past 20 years, in the genetic manipulation of mammalian cells form the scientific basis of gene therapy. A number of strategies are presently being used to replace or augment a dysfunctional gene with a correct copy of itself. Now, a novel approach to correct the dysfunctional gene in the chromosome is being developed. Data obtained from biochemical, cell-based and animal studies suggest that the era of gene repair is dawning. It is now conceivable that inherited and non-inherited disorders might be treated with a small molecular tool designed to fix the mutation directly. Here, the conceptualization of the technique and its barriers to success are discussed.

Animals↗
PubMed1998

Matrix metalloproteinases: implication in vascular matrix remodelling during atherogenesis.

1. The matrix metalloproteinases are a family of at least 16 zinc-dependent endopeptidases possessing catalytic activity against extracellular matrix components. Some members of this family have been implicated in vascular matrix remodelling in the pathogenesis of atherosclerosis. 2. A common, naturally occurring variant has been identified in the promoter of the stromelysin gene with one allele having a run of five adenosines (5A) and the other having six adenosines (6A). Functional analyses have shown that the 6A allele has a lower promoter activity than the 5A allele, which is probably attributable to preferential binding of a putative transcriptional repressor protein. 3. In patients with coronary artery disease, the 6A allele has been found to be associated with progression of atherosclerosis assessed by sequential quantitative angiography. 4. In conclusion, the matrix metalloproteinases may be over-expressed in certain locations in atherosclerotic plaques, which might contribute to local destruction of connective tissue and thus plaque rupture. In the majority of lesional areas, however, matrix synthesis is likely to outstrip matrix degradation, because matrix accumulation is a major feature of most atheromas. This imbalance favouring matrix deposition is likely to be exacerbated in individuals with the 6A6A genotype in whom stromelysin expression is lower due to the weaker stromelysin promoter.

Alleles↗
PubMed1998

Alterations of oncogenes, tumor suppressor genes and growth factors in hepatocellular carcinoma: with relation to tumor size and invasiveness.

OBJECTIVE: To make a better understanding of the molecular mechanisms involved in recurrence and metastasis of the hepatocellular carcinoma (HCC), some invasion related oncogenes, and growth factors have been investigated. METHODS: The studies were separately carried out, the results of which were summarized in this article with relation to tumor size and invasiveness of HCC. RESULTS: The aberration rates of p53 and CDKN2 in HCC were 45.9% and 36.4% respectively, which were higher in invasive HCC compared with non-invasive HCC. H-ras expression was positive in 29.3% of HCC, which was associated with recurrence and extrahepatic metastasis of HCC. Intralesional injection of H-ras antisense gene markedly inhibited the tumor growth and metastasis of HCC in nude mice. The positive rates of transforming growth factor (TGF)-alpha, epidermal growth factor receptor (EGFR) and c-erbB-2 were 45.7%, 47.1% and 92.3% respectively. The expression of EGFR was closely related to TGF-alpha, which was related to HCC recurrence. But no obvious difference of TGF-alpha or c-erbB-2 expression was found between HCC with and without recurrence, or with and without extrahepatic metastasis. Expression of nm23/tissue inhibitor of metalloproteinase (TIMP)-2 was positively associated with the prognosis of HCC patients (Log-rank, P < 0.001). The alterative rates of above-mentioned genes and growth factors in small HCC were slightly lower than that in large ones, but no significant difference was shown except the p53 mutation. CONCLUSIONS: The p53/CDKN2 mutation, over-expression of H-ras/EGFR, were associated with the invasiveness and recurrence of HCC. H-ras antisense gene might be of potential implication in the control of HCC recurrence and metastasis. Expression of nm23/TIMP-2 was closely related to the prognosis of HCC patients. Biological characteristics remained critical points to the prognosis even in small HCC.

Animals↗
PubMed1998

[Expression of p53 and ras p21 gene products in malignant transformed V79 cell induced by various organic components of DEPs].

The effect of various fractions of diesel exhausted particles on the expression of mutant p53 antigen product and ras oncogene p21 product was examined by immunohistochemical method in malignant transformed V79 cell. The result showed that all fractions of diesel exhausted particles (DEPs) could significantly increase the expression of p53 products (P < 0.01). It demonstrated that the organic fractions of DEPs could induce the mutation of p53 suppressor gene in malignant transformed cells. But the expression levels of ras oncogene p21 product were not changed under the same experimental conditions (P > 0.05).

Animals↗
PubMed1998

[Establishment of a human hepatocellular carcinoma (HCC) cell line with high metastatic potential (MHCC97) and its biological characteristics].

OBJECTIVE: To establish and characterize a human hepatocellular carcinoma cell line with high metastatic potential derived from a subcutaneous xenograft of metastatic human HCC in nude mice (LCI-D20). METHODS: Single-cell suspension collected by tearing tumor tissues with forceps was transferred to the tissue culture flasks for culture in vitro in medium DMEM supplemented with 10% human group AB serum. Cytogenetic studies were performed on this cell line using flow cytometry and chromosome G-banding. AFP of theprimary xenografts and lung metastatic lesions was detected by using ABC immunohistochemistry. The rates of its tumorigenicity and metastasis in nude mice were evaluated. RESULTS: The MHCC97 cells showed typical epithelial appearance. Upon subcutaneous or intrahepatic inoculation in nude mice, the xenograft grew and metastasized to the lungs. The metastatic rate was 100%. The cancer cells of lung metastatic foci were AFP positive. Aberrant chromosomes i(1)(q) and der(4) (pter-->q35::?) were its chromosome markers. CONCLUSION: The MHCC97 cell line maintained the biologic characteristics as its original xenografts. The presence of the reported chromosomal aberrations may be related to carcinogenesis and progression of HCC.

Adult↗
PubMed1998

[Clinico-pathological significance of microvessel density and VEGF expression in primary liver cancer].

OBJECTIVE: To evulate the clinico-pathological singnificance of intratumoral microvessel density (MVD) and VEGF expression in primary liver cancer (PLC). METHODS: A retrospective study including 63 postoperative small PLC (diameter < 5 cm) patients was done. One group of 29 patients developed recurrence or metastasis within 2 years. The other group of 34 patients had no evidence of recurrence or metastasis within 2 years. Three PLC sections were taken from each patient, one for H. E. staining, the other two for VEGF and vascular endothelial cell immunohistochemical staining, respectively. MVD was counted by endothelial cells which were highlighted by Bio-UEA-I. RESULTS: The MVD in patients with cancer recurrence or metastasis was (49.6 +/- 29.7) significantly greater than the other group (22.7 +/- 28.2) (P < 0.01). The positive rate of VEGF in cancer recurrence group was 86.2% (25/29), being significantly higher than the other group (47.1%) (P < 0.01). The stage of the tumor, the positive rate of satellite nodules and portal vein embolus were all significantly different between the 2 groups. CONCLUSION: Besides tumor stage, satellite nodules and portal vein embolus, the MVD and VEGF expression are also of prognostic significance.

Carcinoma, Hepatocellular↗
PubMed1998

[An ELISA assay for humulus scandens specific IgE antibodies].

OBJECTIVE: Humulus scandens pollen (HSP) has been proved to be the one of the most important causative factors of autumnal hay fever in China. We established an enzyme immunoassay for specific IgE against HSP by using monoclonal anti-IgE antibody to detect sIgE in 143 patients with autumnal hay fever and 30 healthy volunteers. METHODS: An indirect method of ELISA was developed. The optimal conditions for the test were: coating the allergen at 4 degrees C overnight with a concentration of 12 micrograms/ml; the test serum was diluted 1:16 and incubated with allergen overnight at 37 degrees C; the most suitable dilution and incubative time of the peroxidase-conjugated mouse anti-human IgE antibody were 1:3,000 and 2 hours respectively. RESULTS: The patients' serum level of sIgE was significantly higher than controls (P < 0.001) and correlated significantly with the degree of skin test reaction (P < 0.01). The concordance between the results of skin test and ELISA was 74%-83%. The specificity of the assay was confirmed by heat inactivation and multiple absorption experiments. The coefficients of variation for the intraassay and interassay reproducibility ranged from 1.20%-8.30% and 8.63%-9.22% respectively. CONCLUSIONS: Determination of specific HSP IgE with ELISA assay shows good specificity, sensitivity and reproducibility. It favours clinical practice due to its lower cost.

Allergens↗
PubMed1998

[Morphological characteristics of fruits and seeds of Chinese Caesalpinia and its taxonomic significance].

OBJECTIVE: To set up a toxonomic approach to the morphological characteristics of fruits and seeds of Chinese Caesalpinia. METHOD: The ripe fruits collected in the field are dried in the shade, are surveyed and described and the fruit's and seed's morphological characteristics. RESULT: The interspecific differences of morphological characteristics among the fruits and seeds are obvious. The characteristics are stable. A key for their identification is given. CONCLUSION: The above approach can be used as the taxonomic criteria for species differentiation.

Caesalpinia↗
PubMed1997

Structural requirements for glycolipid antigen recognition by CD1b-restricted T cells.

The human CD1b protein presents lipid antigens to T cells, but the molecular mechanism is unknown. Identification of mycobacterial glucose monomycolate (GMM) as a CD1b-presented glycolipid allowed determination of the structural requirements for its recognition by T cells. Presentation of GMM to CD1b-restricted T cells was not affected by substantial variations in its lipid tails, but was extremely sensitive to chemical alterations in its carbohydrate or other polar substituents. These findings support the view that the recently demonstrated hydrophobic CD1 groove binds the acyl chains of lipid antigens relatively nonspecifically, thereby positioning the hydrophilic components for highly specific interactions with T cell antigen receptors.

Antigen Presentation↗
PubMed1997

Characterization of zinc-substituted cytochrome c by circular dichroism and resonance Raman spectroscopic methods.

Iron(III) in cytochrome c is replaced with zinc(II) by a modification of a method published by others, and the procedure is described in full detail. Three forms of cytochrome c-those containing iron(III), iron(II), and zinc(II)-are examined by circular dichroism spectroscopy and resonance Raman spectroscopy. Spectra of both kinds show that introduction of zinc(II) ions does not appreciably alter the overall structure and conformation of cytochrome c. Resonance Raman spectra indicate the size of the porphyrin "core" that is inconsistent with six-coordination and consistent with five-coordination. Unlike the iron(III) and iron(II) ions, which are bound to two axial ligands (His 18 and Met 80), the zinc(II) ion in cytochrome c seems to be bound to only one, most probably His 18. Evidence pertaining to the question of axial coordination is discussed.

Animals↗
PubMed1997

Nitric oxide (NO) modulates the neurogenic control of blood pressure in rats with chronic renal failure (CRF).

Increased sympathetic nervous system (SNS) activity plays a role in the genesis of hypertension in rats with chronic renal failure (CRF). Because nitric oxide (NO) modulates the activity of the SNS, a deficit of NO synthesis could be responsible for the increased SNS activity in these animals. In the present study, we evaluated the effects of L-arginine and L-NAME on blood pressure and SNS activity-in Sprague Dawley 5/6 nephrectomized or sham-operated rats. SNS activity was determined by measuring norepinephrine turnover rate in several brain nuclei involved in the regulation of blood pressure. In the same brain nuclei, we measured NO content and nitric oxide synthase (NOS) gene expression by semiquantitative measurements of NOS mRNA reverse transcription polymerase chain reaction. In CRF rats, norepinephrine turnover rate was increased in the posterior hypothalamic nuclei, locus coeruleus, paraventricular nuclei, and the rostral ventral medulla, whereas NOS mRNA gene expression and NO2/NO3 content were increased in all brain nuclei tested. L-NAME increased blood pressure and NE turnover rate in several brain nuclei of both control and 5/6 nephrectomized rats. In CRF rats, a significant relationship was present between the percent increment in NOS mRNA gene expression related to the renal failure, and the percent increase in norepinephrine turnover rate caused by L-NAME. This suggests that endogenous NO may partially inhibit the activity of the SNS in brain nuclei involved in the neurogenic regulation of blood pressure, and this inhibition is enhanced in CRF rats. In summary, the increase in SNS activity in the posterior hypothalamic nuclei and in the locus coeruleus of CRF rats is partially mitigated by increased local expression of NOS m-RNA.

Angiotensin II↗
PubMed1997

Renal afferent impulses, the posterior hypothalamus, and hypertension in rats with chronic renal failure.

Hypertension in 5/6 nephrectomized (CRF) rats is partly related to increased activity of the sympathetic nervous system. We have previously shown a greater norepinephrine turnover rate in the posterior hypothalamic nuclei and locus coeruleus of CRF than control rats. Dorsal rhizotomy prevented the rise in blood pressure and the increase in NE turnover rate in the posterior hypothalamus and the locus coeruleus. The studies suggest that afferent impulses from the kidney to central integrative structures in the brain may be responsible for hypertension in CRF rats. To further evaluate the role of renal afferent nerves in the regulation of blood pressure, and whether renal afferent pathways integrate with the posterior hypothalamus, we studied the effects of an intrarenal injection of 50 microliters of 10% phenol on blood pressure and NE secretion from the posterior hypothalamus of Sprague-Dawley rats. Mean arterial pressure increased from 89 +/- 4.0 to 114 +/- 4.3 mm Hg in rats which received intrarenal injection of phenol, but it did not change in rats that received vehicle (95 +/- 4.3 and 89 +/- 3.6 mm Hg, respectively). Renal denervation totally prevented the increase in blood pressure caused by intrarenal injection of phenol. The secretion of NE from the posterior hypothalamus increased from 139 +/- 4.8 to 250 +/- 9.9 pg/ml (P < 0.01) in rats that received intrarenal phenol, but it did not change in rats which received vehicle or in those with renal denervation. In CRF rats NE secretion from the posterior hypothalamus was greater than in control and CRF rats subjected to dorsal rhizotomy. These studies show that afferent impulses from an injured kidney increase NE secretion from the posterior hypothalamus and raise blood pressure. NE secretion is higher in the posterior hypothalamus of CRF than control rats. The posterior hypothalamus appears to be an important integrative structure of the sympathetic regulation of blood pressure.

Afferent Pathways↗
PubMed1997

Structural characterization of the disialogangliosides of murine peritoneal macrophages.

Sialoglycosphingolipids (gangliosides) have been increasingly implicated as regulators of membrane signaling events. Macrophage ganglioside patterns dramatically increase in complexity when murine peritoneal macrophages are stimulated in vivo with the appearance of the sialidase-sensitive monosialoganglioside GM1b (cisGM1) as a major component. Gangliosides from stimulated murine peritoneal macrophages were separated into monosialo and polysialo fractions and the polysialo fraction structurally characterized by enzymatic, chemical, and mass spectra methods. All detectable components of the polysialo fraction were determined to be disialogangliosides. Treatment of the polysialo fraction with Clostridium perfringens sialidase produced mostly the sialidase-resistant monosialoganglioside, GM1a, and a minor amount of asialoGM1. Periodate oxidation and mass spectrometry analyses demonstrated the lack of tandem disialo moieties which indicated the absence of GD1b or GD1c (GD1) entities. The combined data showed the major disialogangliosides consisted of GD1a entities comprising IV3-NeuAc,II3NeuAc-GgOse4Cer, IV3-NeuGc,II3NeuAc-GgOse4Cer, IV3NeuAc,II3NeuGc-GgOse4Cer, and IV3-NeuGc,II3NeuGc-GgOse4Cer. Minor components consisted of GD1alpha entities, IV3NeuAc, III6NeuAcGgOse4Cer, IV3NeuGc, III6NeuGc-GgOse4Cer, and also positional isomer(s) of GD1alpha(NeuAc, NeuGc). These isomeric components were identified by collision analysis and tandem mass spectrometry. Consistent with previous analyses, the ceramide portion of all polysialo (disialo) gangliosides contained solely C18 sphingosine with C16 and C24 fatty acid moieties. These results, combined with the previous characterization of macrophage monosialogangliosides, indicate normal murine macrophage ganglioside biosynthesis proceeds along the "a" ganglioside pathway, e.g., GM3-->GM2-->GM1a-->GD1a, and the proposed asialoganglioside or "alpha" pathway, asialoGM1-->GM1b-->GD1alpha. The presence of totally sialidase-sensitive gangliosides appears to be characteristic of functional murine peritoneal macrophages while they are reduced in genetically impaired cells.

Animals↗
PubMed1997

[Effects of diesel exhaust particle on gap junction intercellular communication].

Scrape-loading and dye transfer technique (SLDT) was used to study the effects of diesel exhaust particle (DEP) on gap junction intercellular communication (GJIC). The results demonstrated that the extract of DEP caused inhibition of gap junction intercellular communication in Balb/c 3T3 cells. It was suggested that inhibition of gap junction intercellular communication in cells may be one of the cause to induce cell transformation.

3T3 Cells↗
PubMed1997

[Changes of gastric pits in intestinal metaplasia of gastric mucosa].

To analyze the changes of gastric pits in intestinal metaplastic mucosa in 20 specimens of subtotal gastrorectomy and to evaluate the relationship between intestinal metaplasia and gastric pits. We made stereomicroscopic observation of the resected parts of the stomach by using dye-staining method. The width of gastric pits was measured by microscope and the histopathological examination was carried out. The features were divided into two groups: intestinal metaplasia and simple chronic superficial gastritis. The stereomicroscopic features of gastric pits were observed in 15.38% type BC, 28.21% type C, 25.64% type CD and 30.77% type D. The width of gastric pits was significantly different between intestinal metaplasia and simple superficial gastritis, especially obvious in severe intestinal metaplasia. The figures of gastric pits were mostly those a type C and type D and widened gastric pits were more obvious in intestinal metaplastic mucosa than in simple chronic superficial gastritis.

Adult↗
PubMed1997

[Antiallergic effects of tranilast in rats and guinea pigs].

Tranilast is an anti-allergic drug. In this study, we made a comparision between the Tranilast synthized by School of Pharmacy WCUMS using new technical and the Tranilast produced by Kissei pharmaceutical Co. LTD, Japan on their antiallergic effects. We found that the two tranilasts had the same antiallergic effects: (1) they inhibit the passive cutaneous anaphylaxis in sensitized rats with the dose of 100, 200 mg/kg(P < 0.01); (2) they inhibit degranulation of mast cells in sensitized rats (10(-5) and 10(-4) mol/L) (P < 0.05); (3) they inhibit schultz-Dale response in sensitized guinea pigs (10(-3) and 10(-4) (mol/L); (4) the inhibit SRS-A release from the lung of sensitized guinea pigs(10(-3), 10(-4) and 10(-5) mol/L) (P < 0.05); and (5) they inhibit the contraction of ileum of normal guinea pigs induced by SRS-A(10(-4) and 10(-3) mol/L).

Animals↗
PubMed1997

[The anti-inflammatory effects of superoxide dismutase].

This paper reports the anti-inflammatory effects of superoxide dismutase (SOD) from pig blood on inflammatory animal models. The experimental results have shown that SOD has significant anti-inflammatory effects. It inhibited carrageenin-induced foot-edema and croton oil induced granulation tissue edema of rats. It also inhibited arthritis induced by egg serum and Freund's adjuvant in rats. The effects were significantly dose-dependent.

Animals↗