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Biomedical subjects

Y C Ko

Publications and source records attributed to Y C Ko.

142 records · Page 8Linked to original sources
PubMed1983

Incidence of hepatitis among students at a university in Taiwan.

The incidence of hepatitis in a general open population of Asian adults was estimated for the first time in this study. A group of 2445 students were first tested when they enrolled at National Taiwan University in 1977; approximately one third were susceptible to hepatitis A and another third to hepatitis B. Most of these students (92%) were retested shortly before their graduation in 1981 to determine the frequency of serologic conversions and clinical hepatitis which had occurred in the 3 1/2 years since they had entered the university. Among 704 susceptible to hepatitis A, 12 (1.7%) had undergone serologic conversions, 33% of which were associated with clinical illness diagnosed as hepatitis. Among 738 susceptible to hepatitis B, 39 (5.3%) had undergone serologic conversions, 12.8% of which were associated with clinical hepatitis. The annual incidence of new infections was 0.5% for hepatitis A and 1.5% for hepatitis B. An additional eight students among the 17 who had clinical hepatitis had no associated conversion of hepatitis A or hepatitis B markers, and were considered to have non-A, non-B hepatitis. No factors could be identified which were predictive of hepatitis risk. No difference in incidence was observed according to sex, type of residence, place of food consumption, or receipt of acupuncture or blood transfusion. Among the 39 students who experienced hepatitis B infections while at the university, there were 2.7% who became hepatitis B surface antigen (HBsAg) carriers. Thus the carrier frequency following hepatitis B infection among Chinese adults is the same or lower than that among Caucasian adults.

Adolescent↗
PubMedDate not supplied

Mutagenicity and aromatic amine content of fumes from heated cooking oils produced in Taiwan.

According to toxicological studies, there are several unidentified mutagens derived from cooking oil fumes appearing in kitchens of Chinese homes where women daily prepare food. Data are limited to an analysis of aromatic amines from cooking oil fumes, which are known to be carcinogenic for bladder cancer. Fume samples from three different commercial cooking oils frequently used in Taiwan were collected and analysed for mutagenicity in the Salmonella/microsome assay. Aromatic amines were extracted from the samples and identified by HPLC and confirmed by gas chromatography/mass spectrometry (GC/MS). Extracts from three cooking oil fumes were found to be mutagenic in the presence of S-9 mix. All samples contained 2-naphthylamine (2-NA) and 4-aminobiphenyl (4-ABP). Concentrations of 2-NA and 4-ABP were 31.5 and 35.7 microg/m3 in fumes from sunflower oil, 31.9 and 26.4 mg/m3 in vegetable oil, and 48.3 and 23.3 microg/m3 in refined-lard oil, respectively. Mutagenicities of the three cooking oil condensates were significantly reduced (P<0.05) by adding the antioxidant catechin (CAT) into the oils before heating. Significant difference existed between the amounts of aromatic amines with and without adding CAT (P<0.05). These results indicate that exposure to cooking oil fumes in Taiwan might be an important but controllable risk factor in the aetiology of bladder cancer.

Amines↗
PubMedDate not supplied

Electrolyte loss in sweat and iodine deficiency in a hot environment.

The authors studied electrolyte loss from profuse sweating in soccer-team players and evaluated the relationship between this source of iodine loss and iodine deficiency. Thirteen male soccer-team players and 100 sedentary students from the same high school were evaluated for 8 d, during which the players were training. The authors analyzed 208 sweat samples to determine losses of iodine, sodium, potassium, and calcium in sweat. Excretion of urinary electrolytes by the subjects was also measured. The mean losses of iodine, sodium, potassium, and calcium in sweat following a 1-hr game were 52 microg, 1,896 mg, 248 mg, and 20 mg, respectively; the ratios of sweat loss to urinary daily loss of the four electrolytes were 0.75, 0.2, 1.88, and 0.92, respectively. Urinary iodine was significantly (p < .02) lower than the normal level of 50 microg/gm creatinine in 38.5% of the soccer players, compared with 2% of the sedentary students. Forty-six percent of the players had Grade I goiter, compared with a mere 1% of the sedentary students (p < .01). The results of the study suggest that loss of iodine through profuse sweating may lead to iodine deficiency, and loss of electrolytes through sweating may have a dietary significance for heat-stressed individuals or for individuals who perform heavy workloads.

Adolescent↗
PubMedDate not supplied

A cohort study on mortality and exposure to polychlorinated biphenyls.

In 1979, an outbreak of food poisoning ("Yu-Cheng") occurred in Central Taiwan, ROC, involving more than 2000 people. The event was caused by ingestion of rice oil contaminated with polychlorinated derivatives of biphenyls, dibenzofurans, and quaterphenyls. A retrospective cohort study on mortality was undertaken, and possible long-term health effects in the affected individuals were studied. The mortality experience of 1940 victims (929 males, 1011 females) between 1980 and 1991 was compared with the expected numbers, which were calculated from national and local mortality rates. By the end of 1991, 102 deaths were identified, thus producing a standardized mortality ratio (SMR) of overall mortality of 0.99 for males and 1.34 for females. Total cancer mortality was lower than in each comparison group. Mortality from liver diseases was elevated significantly (SMR = 3.22), especially during the first 3 y after the food-poisoning event (SMR = 10.76). Increased clinical severity of polychlorinated biphenyl intoxication was associated with increased mortality from all causes and from liver diseases. In summary, there was a positive association between mortality and intoxication dose, and severe polychlorinated biphenyl poisoning acutely affected mainly the liver. A continued follow-up of this cohort would be valuable in the study of long-term health effects of polychlorinated biphenyl poisoning.

Adolescent↗
PubMedDate not supplied

Mortality for certain diseases in areas with high levels of arsenic in drinking water.

Blackfoot disease was prevalent in a limited area on the southwest coast of Taiwan, where artesian well water containing arsenic (median = 0.78 ppm arsenic) had been used for many years. Previous studies of arsenic exposure in the blackfoot disease endemic area have been focused on malignant tumors. We, therefore, conducted this study to analyze mortality of all death causes in blackfoot disease endemic areas and to determine other neglected cancers or noncancer diseases related to artesian well water containing high levels of arsenic. We calculated standardized mortality ratios for cancer and noncancer diseases, by sex, during the period from 1971 to 1994 and compared them to the local reference group (i.e, Chiayi-Tainan County) and the national reference group (i.e., Taiwan population). The results revealed marked standardized mortality ratio differences for the 2 reference groups. Greater mortality was found for males and females with bladder, kidney, skin, lung, nasal-cavity, bone, liver, larynx, colon, and stomach cancers, as well as lymphoma than in the local reference population. With respect to noncancer diseases, we found greater mortality for males and females who had vascular disease, ischemic heart disease, diabetes mellitus, and bronchitis than in the local reference group. Mortalities for other diseases--including rectal cancer, cerebrovascular disease, and other diseases--were higher among cases than the local reference group. Our results indicated that the hazardous effect of arsenic is systemic. Diseases related to arsenic exposure included those reported previously by other investigators, as well as diseases reported in the present study.

Adolescent↗
PubMedDate not supplied

Curcumin inhibits SK-Hep-1 hepatocellular carcinoma cell invasion in vitro and suppresses matrix metalloproteinase-9 secretion.

Curcumin (diferuloylmethane), widely used as a spice and coloring agent in food, possesses potent antioxidant, anti-inflammatory and anticarcinogenic properties. Recently, curcumin was further demonstrated to have an antimetastatic effect in mice. In this study, we attempted to clarify the possible mechanisms of this latter effect of curcumin. A highly invasive SK-Hep-1 cell line of human hepatocellular carcinoma (HCC) was selected for this study. An in vitro assay, without or with Matrigel matrix, was used to quantitate cellular migration and invasion. Gelatin-based zymography was adapted to assay the secretion of matrix metalloproteinase (MMP). We found that curcumin, at 10 microM, inhibited 17.4 and 70.6% of cellular migration and invasion of SK-Hep-1, respectively. Compared with a less invasive human HCC cell line, Huh-7, SK-Hep-1 showed a much higher MMP-9 secretion. Further, and parallel with its anti-invasion activity, curcumin inhibited MMP-9 secretion in SK-Hep-1 in a dose-dependent fashion. We conclude that curcumin has a significant anti-invasion activity in SK-Hep-1 cells, and that this effect is associated with its inhibitory action on MMP-9 secretion.

Antineoplastic Agents↗
PubMedDate not supplied

Successful use of pooled sera to estimate HIV antibody seroprevalence and eliminate all positive cases.

Pooling specimens when testing them in large numbers can save scarce resources and several earlier reports have indicated this to be a feasible strategy. In an HIV antibody mass screening test carried out in our laboratory, we used Dorfman's two-stage model. We sought to establish the optimal number of specimens in a pool, and to achieve maximum efficiency while maintaining both sensitivity and specificity. Before testing for HIV antibody, five positive samples were placed in a set of 1012 sera in a double blind manner, one positive sample into a second set of 1012 sera and none in a third set. The positive rate was assumed to be 0.2% for each set of 1012 sera. As indicated by our model, 22 individual serum samples were placed into each of 46 pools which, when tested by particle agglutination assays, lead to the identification of all positive samples. We concluded that the prevalence rate can be estimated in the first stage, 95% confidence intervals were given, and the efficiency rate could be calculated for the identification of all infected specimens in a large number of samples showing low prevalence rates.

Blood Specimen Collection↗
PubMedDate not supplied

Sexual patterns and human immunodeficiency virus infection among homosexuals in Taiwan.

Between 1988 and 1991, 64 homosexual men and 43 bisexual men were screened for human immunodeficiency virus (HIV) in Southern Taiwan; 5 of them were found to carry HIV antibodies. According to a self-administered questionnaire completed before screening, the average age of the men in the study group was 27 years, and the average duration of practiced homosexuality was 3.8 years. Occupations included student, merchant, laborer, officer, and soldier, and many of the men (45/107) had some junior college or university level education. A relatively high proportion (48/107) of these subjects reported having only 1 sexual partner, and there was a significant association between HIV antibody status and number of sexual partners (P = 0.025). Of the 107 subjects, 58 had practiced anal intercourse and more than a third of them (37/107) indicated that they had participated in receptive anal intercourse, 42 in insertive anal intercourse, and 21 in both of the above. All five carriers of HIV had practiced receptive anal intercourse, in which transmission of HIV from inserter to receptor was highly likely (P = 0.004). Of the men who came forward for HIV testing, the bisexual men tended to be older and often married.

Adult↗