Search PubMed⌕ Search

Biomedical subjects

C Y Chu

Publications and source records attributed to C Y Chu.

54 records · Page 3Linked to original sources
PubMed1992

Inhibition of penta-acetyl geniposide on AFB1-induced genotoxicity in C3H10T1/2 cells.

A new compound, penta-acetyl geniposide ((Ac)5-GP), was obtained from modified extract of Gardenia fructus (San-Jee-Chee in Chinese). The structure of the compound was identified as 1-(beta-D-2',3',4',6'-tetraacetyl-glucopyrannosyloxyl)-1,4a, 5,7a-tetrahydro-7-(acetomethyl)-cyclopentapyran-4-carboxylic acid methyl ester, according to the spectral data. The inhibitory effects of (Ac)5-GP on aflatoxin B1 (AFB1)-induced cytotoxicity and DNA damage were studied. In the investigation of the inhibitory effect of (Ac)5-GP on AFB1-cytotoxicity, the plating efficiency of C3H10T1/2 cells in S-9 activation system was increased. In addition, (Ac)5-GP inhibited the DNA damage of AFB1-treated C3H10T1/2 cells, and it interfered with the inhibitory effect of DNA synthesis caused by AFB1. These results suggest that the reduced DNA damage and the increased DNA synthesis from cultured C3H10T1/2 cells are important mechanisms for the inhibition of AFB1-cytotoxicity by (Ac)5-GP.

Aflatoxin B1↗
PubMed1991

Preparation, characterization, and immunogenicity of conjugates composed of the O-specific polysaccharide of Shigella dysenteriae type 1 (Shiga's bacillus) bound to tetanus toxoid.

The background for developing conjugate vaccines for shigellosis composed of the O-specific polysaccharide (O-SP) bound to a protein is described elsewhere (C. Y. Chu, R. Schneerson, and J. B. Robbins, submitted for publication). Briefly, there is direct evidence for type (lipopolysaccharide [LPS])-specific protection after infection with the wild type or with attenuated strains of shigellae. Prospective studies of Israeli armed forces recruits show a correlation between preexisting serum immunoglobulin G (IgG) LPS antibodies and resistance to shigellosis (D. Cohen, M. S. Green, C. Block, R. Slephon, and I. Ofek, J. Clin. Microbiol. 29:386-389, 1991). In order to elicit IgG LPS-specific antibodies to Shigella dysenteriae type 1, the O-SP of this pathogen was purified and bound to tetanus toxoid (TT) by three schemes. The most immunogenic used a modification of a published method (C. Y. Chu, R. Schneerson, J. B. Robbins, and S. C. Rastogi, Infect. Immun. 40:245-256, 1983). The resultant O-SP-TT conjugates were stable and elicited high levels of IgG O-SP antibodies and booster responses in young mice when injected subcutaneously in saline at 1/10 the proposed human dose. Adsorption onto alum or concurrent administration with monophosphoryl lipid A enhanced both the IgG and IgM antibody responses to the O-SP of the conjugate; both the nonadsorbed and adsorbed conjugates elicited higher rises of IgG than of IgM antibodies. Clinical evaluations of S. dysenteriae type 1 O-SP-TT conjugates are planned.

Animals↗
PubMed1988

Effects of san-huang-hsieh-hsin-tang on central monoaminergic and GABAergic systems in rats.

In this paper, the effects of San-Huang-Hsieh-Hsin-Tang on central monoaminergic and GABAergic systems were studied in rats. It was found that San-Huang-Hsieh-Hsin-Tang significantly (1) prolonged the period from the onset of clonic to tonic convulsions induced by picrotoxin, (2) prolonged the sleep duration induced by hexobarbital, (3) inhibited central catecholaminergic activity, (4) promoted central GABAergic activity, and (5) decreased the turnovers of central norepinephrine and dopamine.

Animals↗
PubMed1982

Value of plasma alpha-1-acid glycoprotein assay in the detection of human colorectal cancer: comparison with carcinoembryonic antigen.

Plasma specimens assessed by caracinoembryonic antigen (CEA) in the clinical laboratory for the detection of colorectal cancer were simultaneously assayed in our laboratory for alpha-1-acid glycoprotein (alpha 1AG), by means of a solid-phase enzyme-linked immunosorbent assay we developed. In 28 patients with colorectal cancer of Dukes A, B, and C classes, elevated levels of alpha 1AG were seen in 12 and of CEA in 8. In 44 patients with distant metastasis (Dukes D lesions), elevated plasma levels of alpha 1AG were seen in 29 and of CEA in 34. No statistical differences in the detection rate were found among these markers in these 2 groups of patients. In 33 cases of non-neoplastic disease involving the large bowel, elevated plasma levels of alpha 1AG were seen in 6, and elevated CEA levels were seen in 7. There was no statistical difference of false positive rates among ;these two markers. Elevated plasma levels of either CEA or alpha 1AG were found in 57 cases of colorectal cancer. This preliminary study suggests that the sensitivity of the plasma alpha 1AG assay is similar to that of the CEA assay in the detection of colorectal cancer. The combination of these two assays increases the detection rate of colorectal cancer significantly.

Adolescent↗
PubMed1981

Plasma alpha 1-acid glycoprotein levels in pregnancy.

One hundred and five determinations of plasma alpha 1-acid glycoprotein (alpha 1AG) levels in 96 women with normal pregnancies were done by an enzyme-linked immunosorbent assay developed in this laboratory. Plasma alpha 1AG levels in pregnant women of all trimesters and 4-10 weeks post-partum period do not differ significantly from those obtained from healthy women of child bearing age. In nine women whose pregnancies were complicated by acute inflammation, plasma levels of alpha 1AG were significantly higher. These findings suggest that in normal pregnancy, alpha 1 AG levels in the plasma remain unchanged. But, pregnancy does not obscure alpha 1 AG response to acute inflammation.

Female↗
PubMed1979

A solid-phase enzyme-linked immunosorbent assay for the quantitation of human plasma alpha 1-acid glycoprotein.

We describe a solid-phase enzyme-linked immunosorbent assay for alpha 1-acid glycoprotein in human plasma. Plasma samples are incubated with alkaline phosphatase-linked, purified alpha 1-acid glycoprotein in alpha 1-acid glycoprotein-specific antibody-coated polystyrene tubes. The alkaline phosphatase that becomes attached to the tube via an immunological reaction between the alpha 1-acid glycoprotein and the specific antibody is measured spectrophotometrically. This assay is accurate reproducible, simple, and economical. As little as 4 microgram of alpha 1-acid glycoprotein per liter can be detected. The normal range for alpha 1-acid glycoprotein in the plasma of healthy adults, as measured by this method, is 0.48-1.27 g/L; the range is significantly different, 0.29-0.73 g/L, for women who are taking oral contraceptive pills.

Adult↗
PubMedDate not supplied

Induction of Fas and Fas-ligand expression in plasmacytoma cells by a cytotoxic factor secreted by murine macrophages.

Induction of tumoricidal activity is one of the major functions of activated macrophages. Our previous study demonstrated that P388D1 murine macrophage-like cells secreted a plasmacytoma cytotoxic factor (PCF) that selectively killed certain tumor cell lines including MOPC-315 plasmacytoma in vitro. Our subsequent studies demonstrated that PCF killed MOPC-315 cells by induction of apoptosis. In this report, the involvement of Fas and Fas ligand (FasL) in PCF-induced apoptosis was investigated. Results suggest that expression of Fas mRNA time-dependently increased in PCF-treated cells and reached an optimal level after 36 h of treatment. The augmented effect of PCF on Fas mRNA expression was significantly reduced by the addition of CB7.C2, an anti-PCF monoclonal antibody. The expression of FasL mRNA was also induced by PCF and reached an optimal level at 24 h, but sharply decreased after 36 h of treatment. Caspase-3 is one of the proteolytic enzymes that can be activated by the Fas-FasL interaction. In our studies, the enzymatic activity of caspase-3 was significantly induced by PCF after 6 h of treatment and reached an optimal level at 12 h. The augmented effect of PCF on caspase activity was significantly reduced by the addition of CB7.C2 and the caspase-3-specific inhibitor, DEVD-fmk. Therefore, PCF-treated plasmacytoma cells might undergo apoptosis via interaction between Fas and FasL.

Animals↗
PubMedDate not supplied

Protective effects of capillarisin on tert-butylhydroperoxide-induced oxidative damage in rat primary hepatocytes.

Capillarisin (Cap), a main constituent of Artemisia capillaris (Compositae), was studied for its antioxidant bioactivity. In the preliminary study, Cap expressed a antioxidant property by its capacity for quenching the free radicals of 1,1-diphenyl-2-picrylhydrazyl (DPPH). This antioxidant bioactivity of Cap was investigated further using a model of t-butylhydroperoxide (t-BHP)-induced cytotoxicity and genotoxicity in rat primary hepatocytes. Results presented here demonstrate that Cap, at concentrations of 0.01-1.00 mg/ml, significantly decreased the leakage of lactate dehydrogenase (LDH) and alanine aminotransferase (ALT) and the formation of malondialdehyde (MDA) induced by 30 min treatment of t-BHP (1.5 mM) in primary cultured rat hepatocytes. Cap also attenuated the t-BHP-induced diminution of glutathione (GSH) and high level of DNA repaired synthesis. These results lead to speculation that Cap presents inhibitory effects against t-BHP-caused cytotoxicity and genotoxicity in rat primary hepatocyte cultures at least via two distinct pathways, stabilizing the GSH system and quenching free radicals.

Alanine Transaminase↗
PubMedDate not supplied

Gemcitabine-induced acute lipodermatosclerosis-like reaction.

Gemcitabine is considered to be a well-tolerated and safe cytostatic drug because of the relative lack of side effects. Cutaneous reactions due to gemcitabine treatment, including alopecia and maculopapular eruption, are well known. We report one patient with squamous cell carcinoma of the lung who developed a gemcitabine-induced cutaneous reaction mimicking acute lipodermatosclerosis. This case has never been reported in the literature before.

Acute Disease↗