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Biomedical subjects

C M Sun

Publications and source records attributed to C M Sun.

29 records · Page 2Linked to original sources
PubMed1996

Role of oxidative DNA damage in hydroxychavicol-induced genotoxicity.

Chewing betel quid has been linked to the development of oral cancer. In Taiwan, fresh Piper betle inflorescence is uniquely added to betel quid, and hydroxychavicol is the major phenolic components of P.betle inflorescence. In this study, we tested the mutagenic potential of hydroxychavicol in Salmonella typhimurium TA97, TA98, TA100 and TA102 with and without Aroclor-1254 induced S9 fraction. The results showed that hydroxychavicol was positive in S.typhimurium TA102 without metabolic activation. This increase in revertants was partially inhibited by catalase and superoxide dismutase. In Chinese hamster ovary (CHO-K1) cells, hydroxychavicol induced chromosome aberrations in a dose-dependent manner (10-50 microM) and the majority were chromosome-type aberrations. Hydroxychavicol also significantly increased the frequency of micronuclei in CHO-K1 cells up to 3-fold at a concentration of 40 microM. In addition, hydroxychavicol dose-dependently (0.1-20 microM) induced copper-dependent strand breaks in plasmid DNA. We further tested the oxidative DNA damage potential of hydroxychavicol by measuring 8-hydroxydeoxyguanosine (8-OH-dG) formation in CHO-K1 cells following an 18-h incubation and found that hydroxychavicol (6.25-100 microM) induced 8-OH-dG levels dose-dependently. The increase of 8-OH-dG formation was positively correlated (r = 0.79) with the hydroxychavicol-induced cytotoxicity. In conclusion, hydroxychavicol may exert its genotoxic potential through oxidative DNA damage.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1995

The novel desmethyldestruxin B2, from Metarhizium anisopliae, that suppresses hepatitis B virus surface antigen production in human hepatoma cells.

We have examined the antiviral activity of a crude extract prepared from the culture medium of the fungus Metarhizium anisopliae. Eight active destruxins were identified which showed strong suppressive effect on the production of the hepatitis B surface antigen (HBsAg) in human hepatoma Hep3B cells. One new compound, desmethyldestruxin B2 [1], was isolated from M. anisopliae. This structure was determined based on its nmr and mass spectral data.

Animals↗
PubMed1992

[Clinical study of rapid bladder filling agent].

The Rapid Bladder Filling Agent (RBFA) was prepared with Polyporus umbellatus, Poria cocos and Furosemidum. The urinary volume and the best filling time of urinary bladder were observed with ultrasonography in 211 cases. The result showed that in experimental group the largest urinary volume in unit time was more than that in control group and shortest filling time was shorter (30.35 +/- 7.9 min) in comparing with control group (145.6 +/- 50.1 min). Clinical observation for 1180 cases proved that the RBFA had the effects of raising the quality of ultrasonographic examination and escalating work efficiency, shortening the waiting time of patients and relieving patients' suffering from excessive filling of urinary bladder. The effective time of the RBFA was fast but the duration was short. The RBFA had no adverse effect.

Adult↗
PubMed1989

Putative role of adenohypophysis in the osmoregulation of tilapia larvae (Oreochromis mossambicus; Teleostei): an ultrastructure study.

Ultrastructure of the secretory cells in the adenohypophysis of tilapia (Oreochromis mossambicus) larvae hatched in fresh water or sea water was compared. Adenohypophysis of newly hatched larvae of tilapia is a short columnar body attached to the ventral floor of the diencephalon. The adenohypophysis is at its early differentiation stage, i.e., various types of secretory cells are still undistinguishable. Only part of the cells in the putative rostral pars distalis look like typical endocrine cells, containing well-developed rough endoplasmic reticulum, Golgi apparatus, and numerous secretory granules. The average size of secretory granules in freshwater-hatched larvae is significantly larger than those in seawater-hatched larvae (12,936 +/- 2854 nm2, N = 11 vs 3375 +/- 810 nm2, N = 10), suggesting some role of adenohypophysis in the osmoregulation of the early developmental stage of teleosts.

Animals↗
PubMedDate not supplied

A clinical study of schizophrenic suicides. 42 cases in Taiwan.

A clinical study of 25 male and 17 female schizophrenic suicides is presented. Jumping from a height was the most common method used. The 42 suicidal schizophrenics in Taiwan were compared with both 84 sex- and age-matched and 60 5-year illness course non-suicidal schizophrenic control groups. The suicidal schizophrenics were not significantly different from the non-suicidal counterparts of both control groups with regard to age, sex, ethnicity, religion, educational background, the presence of suicide cases in the family history, and the presence of insight, but were significantly different in characteristics of a history of previous suicide attempts, presence of psychotic symptoms during their final month, depression during their final month, a history of depression, a history of previous psychiatric hospitalizations, and the number of hospitalizations. We discuss the findings from this study and others in the literature in the context of the different clinical and socio-cultural backgrounds of these Taiwanese schizophrenic suicides.

Adult↗
PubMedDate not supplied

Combinatorial liquid-phase synthesis of structurally diverse benzimidazole libraries.

An expedient liquid-phase synthesis for construction of the diverse benzimidazole libraries is described. Nucleophilic aryl substitution of poly(ethylene glycol)-supported 4-fluoro-3-nitrobenzoic acid 3 with several primary amines under basic conditions, followed by Zn/NH(4)Cl mediated nitro group reduction, gave the PEG bound diamines 5. Subsequent cyclization of immobilized o-phenylenediamine 5 using thiocarbonyldiimidazole (TCD) or thiophosgene in dichloromethane furnished benzimidazole-2-thiones 6. Treatment of 6 with alkyl halides and benzylic halides in the presence of triethylamine provided 1-substituted-2-alkylthio-5-carbamoylbenzimidazoles on the support. The desired products 8 were severed from the PEG under mild conditions in high yield and high purity.

Benzimidazoles↗