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Biomedical subjects

C C Yeh

Publications and source records attributed to C C Yeh.

69 records · Page 4Linked to original sources
PubMed1995

Oxidative damage and antioxidant status in the lungs and bronchoalveolar lavage fluid of rats exposed chronically to cigarette smoke.

The effect of chronic smoke exposure on oxidative damage and antioxidant status was studied in rats. Ten-week-old female Sprague-Dawley rats were exposed to fresh mainstream cigarette smoke or filtered room air twice daily, or maintained as room controls, for 65 weeks. Animals were sacrificed 18-20 hours after the last treatment. The bronchoalveolar lavage (BAL) fluid, lung tissues, and plasma were processed to assess oxidative damage and antioxidant status. Compared with sham and room control groups, the levels of conjugated dienes and alpha-tocopheryl quinone were significantly higher in the lung tissues of rats exposed to cigarette smoke. The levels of malondialdehyde, protein carbonyls, reduced glutathione (GSH), ascorbic acid and vitamin E, and activities of catalase and GSH peroxidase in the lung tissues were not significantly altered by smoke exposure. No significant differences in any measurements were found in BAL fluid and plasma among the experimental groups. The results obtained support the view that cigarette smoking increases oxidative stress and suggest a metabolic adaptation of antioxidant systems following chronic smoke exposure.

Animals↗
PubMed1994

Utilization and sources of blood components in Taiwan.

A three-year survey program, sponsored by the Department of Health, Taiwan R.O.C., was conducted from 1990 to 1992 to investigate blood utilization and blood sources in Taiwanese hospitals. The survey covered the period from January 1989 to December 1991. The hospitals surveyed included nine to 12 medical centers, 40 to 48 regional hospitals, 148 to 163 community hospitals, and 363 to 451 specialty hospitals. Their respective response rates for three consecutive years were 75.0%, 87.9% and 84.1%. Approximately 86% (for 1988) to 98% (for 1991) of all units transfused in Taiwan were surveyed (unit of blood = 250 ml). Utilization of various blood components, ie, red blood cell (RBC) components, frozen plasma (FP), cryoprecipitate (CRYO) and platelets (PLT), showed a trend of continuous increase. In 1991, 12 medical centers and 48 regional hospitals consumed 81.4% of the RBC components, including whole blood (WB) and packed red blood cells (PRBC), while the remaining 18.6% was consumed by 138 community hospitals and 282 specialty hospitals. The average blood utilization of medical centers was 37,383 units of RBC components, 30,949 units of FP, 6,990 units of CRYO, and 21,353 units of PLT per hospital. Utilization of RBC components was 7,191 units per regional hospital, 1,012 units per community hospital, and 148 units per specialty hospital. In 1991, almost all other components consumed in Taiwan, namely FP, CRYO and PLT, were utilized by medical centers and regional hospitals. WB and PRBC sources showed a drastic decline in paid donation, a modest decrease in hospital blood drawn from voluntary donors and an increasing role of the BLood Donation Association (BDA) in volunteer blood donation.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Component Transfusion↗
PubMed1993

Benign villous adenomas of the ampulla of Vater: report of two cases.

Benign tumors of the ampulla of Vater are uncommon. We report on two patients with epigastralgia, jaundice and pancreatitis caused by villous adenoma of the ampulla of Vater, combined with biliary tract stones, who were treated at National Taiwan University Hospital. Definite diagnoses were made by endoscopic retrograde cholangiopancreatography and biopsy. Their medical unsuitability for radical pancreaticoduodenectomy led us to revive the procedure of wide local excision of these tumors with reimplantation of the pancreatic duct and double sphincteroplasty. Operative time and blood loss were substantially less, and postoperative recovery was relatively uncomplicated. Hepatic resection for intrahepatic stones was performed later in the first case. Postoperative follow-up at 2.5 years showed no tumor recurrence. We suggest that local resection of benign ampullary tumors with double sphincteroplasty is the procedure of choice in high-risk patients.

Adenoma, Villous↗
PubMed1991

The basic isoelectric form of alpha-L-fucosidase from the hepatopancreas of the shrimp Penaeus monodon (Crustacea: Decapoda).

1. alpha-L-Fucosidase was purified ca 10,889-fold to homogeneity from Penaeus monodon, with a final spec. act. of 31,250 U/mg of protein. 2. By using SDS-polyacrylamide gel electrophoresis, the monomers of shrimp alpha-L-fucosidase were discovered to have mol. wts of 63,000 and those of human placental enzyme, 46,000 and 20,000. Since the active shrimp alpha-L-fucosidase was found to have a mol. wt of 233,000 by Superose 12 FPLC, it was concluded that the purified shrimp enzyme was tetrameric. 3. In contrast to the discovery of thermolability with human placental alpha-L-fucosidase, the shrimp enzyme was found to be stable to heating at 65 degrees C for 10 min. 4. The shrimp alpha-L-fucosidase has an isoelectric point (pI) of 8.5, but the human placental enzyme has a pI of 4.0. The shrimp enzyme was sialyated. 5. The shrimp alpha-L-fucosidase has a pH optimum at 5.5 and its Km was 22.2 microM with 4-methyl-umbelliferyl-alpha-L-fucopyranoside as substrate. The human enzyme has a broad pH optimum between 5.0 and 6.5.

Animals↗
PubMed1990

[The biocontrol of container-breeding mosquitoes by using Toxorhynchites].

Container-breeding mosquitoes not only bite people but also transmit many human and animal diseases. The problem with chemical control of these mosquitoes is that the breeding sites are always well dispersed and not easily located, and more manenergy and money are required to treat them individually. Since the adverse effects of pesticides on vector control have been recognized, Toxorhynchites mosquitoes are being reconsidered as a means of reducing the populations of other mosquito species. The bionomic interaction of predator and prey, mass rearing, and some examples of biological control of Toxorhynchites are discussed in this article. Integrated controls combining periodic mass release of gravid Toxorhynchites females and ULV pesticide applications can be used to suppress container-breeding mosquitoes.

Animals↗
PubMed1985

Discovery and epidemiology of PCB poisoning in Taiwan: a four-year followup.

An outbreak of polychlorinated biphenyl (PCB) poisoning from the consumption of contaminated rice oil, covering four counties in central Taiwan, was investigated. There were 1843 cases by the end of 1980. The highest frequency of incidence occurred during the period from March to July 1979. The severity of clinical manifestations varied. Most patients showed symptoms of mild or moderate severity. The major age group affected was between 11 and 20 years old. Most of the victims were students and factory workers. The amount of PCB intake in each victim was estimated to be 0.7 to 1.84 g and the latent period from the time of intake to the onset of clinical manifestations was approximately 3 to 4 months. The patients' blood PCB concentrations ranged from 3 ppb to 1156 ppb; 44.27% of 613 patients had levels of 51 to 100 ppb and 27.6% PCB blood levels over 100 ppb. In the course of 3.5 years, 2061 persons were determined to be PCB poisoning victims. Now, except for a few severe cases, their skin symptoms are very much improved. Thirty-nine babies showing hyperpigmentation were born from PCB-poisoned mothers. The fatality rate was high: eight of them died. Another 24 deaths were reported among the PCB-poisoned group, almost half of them (12) from hepatoma, liver cirrhosis or liver diseases with hepatomegaly.

Adolescent↗
PubMed1984

Discovery and epidemiology of PCB poisoning in Taiwan.

An outbreak of PCB poisoning through consumption of the contaminated rice oil in Central Taiwan was investigated. It covered four counties and there were 1,843 cases by the end of 1980. The highest frequency of incidence occurred during the period from March to July 1979. Severity of clinical manifestations was graded, most patients exhibiting mild or moderate severity. The major age group of the outbreak was between 11 to 20 years old. Most of the victims were students and factory workers. The amount of PCB intake in each victim was estimated to be 0.7 to 1.84 gm and the latent period from the time of intake to the onset of clinical manifestations was approximately three to four months. The patients' blood PCB concentrations ranged from 3 to 1,156 ppb. In 613 patients, 44.37% (272 patients) had PCB levels of 51-100 ppb, and 27.57% (169 patients) had levels over 100 ppb.

Acne Vulgaris↗
PubMed1984

Discovery and epidemiology of PCB poisoning in Taiwan.

An outbreak of PCB poisoning through consumption of the contaminated rice Oil in Central Taiwan was investigated. It covered four counties and there were 1,843 cases by the end of 1980. The highest frequency of incidence occurred during the period from March to July 1979. Severity of clinical manifestations was graded, most patients exhibiting mild or moderate severity. The major age group of the outbreak was between 11 to 20 years old. Most of the victims were students and factory workers. The amount of PCB intake in each victim was estimated to be 0.7 to 1.84 gm and the latent period from the time of intake to the onset of clinical manifestations was approximately three to four months. The patients' blood PCB concentrations ranged from 3 to 1,156 ppb. In 613 patients, 44.37% (272 patients) had PCB levels of 51-100 ppb, and 27.51% (169 patients) had levels over 100 ppb.

Adolescent↗
PubMedDate not supplied

Effects of aspirin on arylamine N -acetyltransferase activity and DNA adducts in human bladder tumour cells.

Aspirin (acetylsalicylic acid) was used to determine the inhibition of arylamine N-acetyltransferase (NAT) activity and DNA adduct formation in a human bladder tumour cell line (T24). The activity of NAT was measured by high-performance liquid chromatography, assaying for the amounts of N-acetyl-2-aminofluorene and N-acetyl-p-aminobenzoic acid and remaining 2-aminofluorene and p-aminobenzoic acid. Two assay systems were used: one with cytosol and the other with intact cells. High-performance liquid chromatography was also used to analyse for the 2-aminofluorene-DNA adducts. Intact bladder tumour cells were used. The results demonstrated that NAT activity and 2-aminofluorene-DNA adduct formation in human bladder tumour cells were inhibited by acetylsalicylic acid in a dose-dependent manner. The effects of acetylsalicylic acid on the values of the apparent K(m) and V(max) were also determined in both examined systems. The data also indicated that acetylsalicylic acid decreased the apparent values of K(m) and V(max) from human bladder tumour cells in both cytosol and intact cells.

2-Acetylaminofluorene↗
PubMedDate not supplied

Inhibition of N-acetyltransferase activity and DNA-2-aminofluorene adducts by glycyrrhizic acid in human colon tumour cells.

Glycyrrhizic acid (GA) was tested for inhibition of arylamine N-acetyltransferase (NAT) activity in a human colon tumour (adenocarcinoma) cell line (colo 205). Two assay systems were performed, one with cellular cytosols (9000g supernatant), the other with intact colon tumour cell cultures. The NAT activity in a human colon tumour cell line was inhibited by GA in a dose-dependent manner in both types of systems examined. The data also indicated that GA decreased the apparent values of K(m) and V(max) of NAT enzymes from human colon tumour cells in both examined systems. The DNA-2-aminofluorene adduct formation in human colon tumour cells were inhibited by GA. This report is the first to demonstrate that GA does inhibit human colon tumour cell NAT activity and DNA adduct formation.

4-Aminobenzoic Acid↗
PubMedDate not supplied

Effects of the immunomodulator tilorone on the acetylation of 2-aminofluorene and DNA-2-aminofluorene adducts in the rats.

The present studies were undertaken to determine the effect of tilorone dihydrochloride (a synthetic interferon inducer) on the in vivo acetylation of 2-aminofluorene and DNA-2-aminofluorene adducts. For in vivo examination, pretreatment with tilorone dihydrochloride (50 mg/kg) 48 hr prior to the administration of 2-aminofluorene (50 mg/kg) resulted in a 35% and 29% increase in the fecal and urinary recovery of N-acetyl-2-aminofluorene and a 52% increase in the metabolic clearance of 2-aminofluorene to N-acetyl-2-aminofluorene. Following the exposure of rats to the 2-aminofluorene with or without pretreatment with tilorone dihydrochloride, DNA-2-aminofluorene adducts were determined in liver, bladder, lung and also in circulating leukocytes. The DNA-2-aminofluorene adducts in liver were increased by pretreatment with tilorone dihydrochloride. This is the first demonstration of tilorone-induced increasing in N-acetylation of carcinogens and DNA-carcinogen adducts in vivo.

2-Acetylaminofluorene↗
PubMedDate not supplied

Effects of the butylated hydroxyanisole and butylated hydroxytoluene on the DNA adduct formation and arylamines N-acetyltransferase activity in human colon tumor cells.

The effects of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) on N-acetyltransferase (NAT) activity were examined using a human colon tumor cell line (colo 205). BHA or BHT were added to the cytosols or to the medium of human colon tumor cells: The NAT activity was measured by high performance liquid chromatography, assaying the amounts of acetylated 2-aminoflluorene (AAF), p aminobenzoic acid (N-Ac-PABA), nonacetylated 2 aminofluorene (AF) and p-aminobenzoic acid (PABA). The NAT activity in the human colon tumor cells and cytosols was suppressed by BHA or BHT in a dose-dependent manner. The apparent values of Km and Vmax of NAT of human colon tumor cells were also decreased by BHA or BHT in cytosols and in intact cells. BHA or BHT may act as a noncompetitive inhibitor. After the incubation of human colon tumor cells with AF in the presence of BHA or BHT, the cells were recovered and DNA was prepared and hydrolysed to nucleotides. Adducted nucleotides were extracted into butanol and AF-DNA adducts were analysed by HPLC. The results also demonstrated that when BHA or BHT was added to the media, a decrease in AF-DNA adduct formation was seen in the human colon tumor cells. The finding of AF-DNA adduct formation in cultured human colon tumor cells suggest the possibility of using cultured cells for assessing arylamine-induced DNA damage.

2-Acetylaminofluorene↗