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Biomedical subjects

T M Lin

Publications and source records attributed to T M Lin.

At least 73 records · Page 4Linked to original sources

Epidemiological characteristics of twinning rates in Taiwan.

Delivery records of public hospitals and birth certificates of household registration offices were examined to study the epidemiological characteristics of twinning rate from 1955 to 1984 in Taiwan. The MZ twinning rate was consistently higher than the DZ rate during the study period. The DZ rate declined steadily from 2.7 per 1000 in 1955 to 1.3 per 1000 in 1975, and then gradually increased to 3.6 per 1000 in 1984. The MZ rate peaked periodically in 1956, 1966 and 1976, and gradually increased from 3.3 per 1000 in 1978 to 5.9 per 1000 in 1986. Both MZ and DZ rates were higher in urban than in rural areas and they were also higher in northern Taiwan than elsewhere in the island. While both MZ and DZ rates increased with maternal age and parity, the maternal age difference and the parity difference were more striking in DZ than in MZ rates. The international comparison also showed a greater racial difference in maternal age-specific DZ than MZ twinning rates; and the older the maternal age, the greater the international discrepancy in DZ rates.

Birth Rate↗

Species variation of gonadotropic activity in an in vitro assay measuring androgen formation by carp (Cyprinus carpio) testis with special reference to bioassay of piscine gonadotropins.

The objectives of this study were to establish a suitable and validated in vitro bioassay of piscine gonadotropins (GTHs) by using a carp testis androgen production system and to compare the androgenic responses in such an assay to gonadotropins from various vertebrate species. The testes from mature carp with gonadosomatic indices of 8-30% were used. Androgen production was first compared with respect to methods for preparation of the carp testis (sliced, minced, homogenized, and collagenase-dispersed testis preparations). The time course of androgen formation, the effects of xanthine and theophylline, and other factors on androgen production also were investigated. Theophylline was more effective than xanthine in potentiation of gonadotropin-evoked androgen formation by carp testis. The testis preparations were incubated in medium 199 (pH 7.40) containing 2 mM theophylline with shaking at 100 cycles/min at 25 degrees C for 4 hr. Homogenized testis preparations had limited ability for androgen production, while sliced, minced, and minced-collagenase-dispersed testis preparations were highly responsive to gonadotropins for androgen production. The minced testis preparation, utilizing 100 mg/ml incubation medium per vial, was chosen as the standard incubation procedure in this study. The minced testis androgen production assay was highly sensitive to gonadotropins from several piscine species (silver carp, common carp, and salmon), and all these GTHs produced parallel dose-related androgen production curves. Mammalian GTHs were also capable of promoting androgen formation by carp testis, but they were much less potent than were piscine GTHs. Pregnant mares' serum gonadotropin (PMSG) was more effective than human chorionic gonadotropin (hCG) in evoking carp testis androgen production.(ABSTRACT TRUNCATED AT 250 WORDS)

Androgens↗

Mortality of hepatoma and cirrhosis of liver in Taiwan.

A study of mortality from hepatoma and hepatic cirrhosis was conducted in Taiwan, where their mortality rates are among the highest in the world in 1980 being 26.10 and 8.14 per 100,000 population for males and females, respectively, for hepatoma, and 33.01 and 12.90 for males and females, respectively, for cirrhosis. The secular trends of hepatoma and hepatic cirrhosis death rates have been increasing, especially in males, with consequent increase in the sex ratio. The large difference in mortality rates between males and females and the increasing trends in the sex ratio suggest that other factors besides hepatitis B virus (HBV), are involved in the aetiology of hepatoma and cirrhosis of liver.

Adolescent↗

A retrospective study on malignant neoplasms of bladder, lung and liver in blackfoot disease endemic area in Taiwan.

A total of 69 bladder cancer, 76 lung cancer and 59 liver cancer deceased cases and 368 alive community controls group-matched on age and sex were studied to evaluate the association between high-arsenic artesian well water and cancers in the endemic area of blackfoot disease (BFD), a unique peripheral vascular disease related to continuous arsenic exposure. According to a standardized structured questionnaire, information on risk factors was obtained through proxy interview of the cases and personal interview of the controls. A positive dose-response relationship was observed between the exposure to artesian well water and cancers of bladder, lung and liver. The age-sex-adjusted odds ratios of developing bladder, lung and liver cancers for those who had used artesian well water for 40 or more years were 3.90, 3.39, and 2.67, respectively, as compared with those who never used artesian well water. Multiple binary logistic regression analyses showed that the dose-response relationships and odds ratios remained much the same while other risk factors were further adjusted.

Aged↗

An enzyme immunoassay for immunoglobulin M antibodies to Toxoplasma gondii which is not affected by rheumatoid factor or immunoglobulin G antibodies.

An enzyme-linked immunosorbent assay (ELISA) for total antibodies to Toxoplasma gondii was modified to measure specific immunoglobulin M (IgM) antibodies. The assay requires three incubation periods totaling 2 h and enzyme-labeled-heavy-chain-specific antibodies to human IgM. The objective read-out in absorbance was normalized to percent of a standardized positive control for interpretations. No difference was observed between the assay results with or without previous absorption of the samples by Staphylococcus aureus protein A to remove most of the IgG antibodies. Addition of serum containing very high levels of IgG antibodies to another containing both IgG and IgM antibodies did not change the IgM assay values for the latter. None of the 22 sera containing high levels of IgM rheumatoid factor (RF) gave positive ELISA IgM results, even though 8 of them also had high levels of IgG toxoplasma antibodies. Mixtures of sera containing high concentrations of RF with sera having high levels of IgG toxoplasma antibodies also failed to show any false-positive reactions in the IgM toxoplasma assay. Thus, this ELISA for T. gondii IgM antibodies was not affected by IgG toxoplasma antibodies and RF.

Adult↗

Treponemal antibody-absorbent enzyme immunoassay for syphilis.

An enzyme immunoassay for the diagnosis of syphilis (ELISA-SY) was developed with solid-phase extracts of Treponema pallidum, specimen diluent containing Reiter treponeme absorbent, and three 30-min incubations. The ELISA-SY results were determined in comparison with a standardized positive control and reported as a percentage of strong positive control. In tests with 1,005 serum samples from a venereal disease clinic and other sources, 98.2% agreement was found with fluorescent treponemal antibody-absorption (FTA-ABS) results, and 98.3% agreement was found with T. pallidum passive hemagglutination (PHA) findings. Only 1 of 29 sera originally considered to be biologically false-positive by ELISA-SY; the latter specimen was also positive by PHA and FTA-ABS tests performed in our laboratories. Serum samples from clinically diagnosed syphilitics (16 primary-stage isolates, 7 secondary-stage isolates, and 3-latent-stage isolates) were all positive by ELISA-SY, FTA-ABS, and PHA. Serum samples from 51 newborns suspected of having syphilis on the basis of positive cardiolipin flocculation tests showed 98% agreement of ELISA-SY results with FTA-ABS and PHA findings. Sera from all 61 patients with a variety of autoimmune and other diseases known to be associated with biologically false-positive reactions for syphilis were negative by this ELISA-SY. The specificity of the ELISA procedure for T. pallidum antibody was also confirmed immunologically by blocking experiments.

Antibodies↗

Rapid dot enzyme immunoassay for the detection of antibodies to cytomegalovirus.

Cytomegalovirus (CMV) antigen was coated onto a white opaque plastic card as small dots inside circles marked in the microtiter plate well pattern. The card with antigen dots could be cut according to the number of test samples to be assayed. Small drops of undiluted serum samples, goat antibodies to human immunoglobulin G labeled with alkaline phosphatase, and finally substrate (5-bromo-4-chloro-3-indolyl phosphate) were sequentially added to the antigen spots and incubated in the open air at room temperature for 5 min each. The antigen dots showed blue color for sera with immunoglobulin G antibodies to cytomegalovirus but no color for those without. The developed antigen dots could be rinsed with water and kept as permanent records. For the assay of a large number of serum samples, a modified procedure with serum diluted 1:10 and longer first two incubations (20 min each) was found to be more comfortable to perform. The results of this assay for 123 undiluted and 256 diluted serum samples revealed very good correlations with those obtained by a commercially available test kit for immunoglobulin G antibodies to cytomegalovirus with 97 and 99% agreement, respectively. This dot test was very reproducible and required no instrumentation. The reagents, including coated antigen dots, are stable at room temperature for at least 2 months and are ready for use.

Adult↗

Actions of nizatidine, a selective histamine H2-receptor antagonist, on gastric acid secretion in dogs, rats and frogs.

Nizatidine (LY139037), a selective histamine H2-receptor antagonist, is a potent inhibitor of gastric acid secretion. It was 17.8 times as active as cimetidine on histamine (10(-5) M)-induced secretion from the isolated gastric mucosa of the bullfrog. Nizatidine was 8.9 times as active as cimetidine on basal acid secretion of the chronic gastric fistula rats after s.c. administration. Against acid secretion from the vagally innervated gastric fistula and Heidenhain pouch of dogs stimulated with submaximal doses of histamine, methacholine and gastrin, nizatidine was, respectively, 6.5, 5 and 4.7 times as active as cimetidine by i.v. administration. Nizatidine was very well absorbed from the gut and was 5 to 10 times as active as cimetidine on gastric acid secretion of dogs induced by submaximal and maximal doses of histamine when given p.o. Equal molar doses of nizatidine showed equal peak effects when given i.v., s.c. or i.m. Pharmacological data indicate that nizatidine is safe and effective as an agent for the control of excessive gastric acid secretion.

Administration, Oral↗

Actions of nizatidine on the rat uterus, dog stomach and experimentally induced gastric lesions.

Nizatidine is a potent and selective antagonist of histamine. The histamine-induced relaxation of the KCl-treated rat uterus was inhibited dose-dependently by nizatidine. The inhibition was characterized by displacement of the dose-response to histamine to the right, in parallel, without depression of the maximum. The affinity of nizatidine for the histamine H2-receptor of the rat uterus was about 10 times that of cimetidine. The steady-state dose-response acid outputs stimulated by histamine from the Heidenhain pouch and the gastric fistula were also shifted dose-dependently by nizatidine, in parallel, to the right. The inhibition was consistent with a surmountable antagonism of histamine. At high (10(-4) to 10(-3) M) concentrations, nizatidine increased the motility of the guinea pig stomach and duodenum in vitro; this effect was abolished noncompetitively by atropine (10(-8) M) and pyrilamine (10(-4) M). Both nizatidine and cimetidine administered s.c. showed "cytoprotective" action by reducing the gastric lesions induced by 1) aminoguinidine and pylorus ligation and 2) HCl plus aspirin in the rat. On a weight and molar basis, nizatidine was 4 and 5.25 times as effective as cimetidine, respectively. This cytoprotective action of nizatidine was found when acidity and total acid load in the stomach were not affected by the histamine H2-receptor antagonist.

Animals↗

Malignant neoplasms among residents of a blackfoot disease-endemic area in Taiwan: high-arsenic artesian well water and cancers.

The objective of this study is to elucidate the association between high-arsenic artesian well water and cancers in endemic area of blackfoot disease, a unique peripheral vascular disease related to continuous arsenic exposure. As compared with the general population in Taiwan, both the standardized mortality ratio (SMR) and cumulative mortality rate were significantly high in blackfoot disease-endemic areas for cancers of bladder, kidney, skin, lung, liver, and colon. The SMRs for cancers of bladder, kidney, skin, lung, liver, and colon were 1100, 772, 534, 320, 170, and 160, respectively, for males, and 2009, 1119, 652, 413, 229, and 168, respectively, for females. A dose-response relationship was observed between SMRs of the cancers and blackfoot disease prevalence rate of the villages and townships in the endemic areas. SMRs of cancers were greater in villages where only artesian wells were used as the drinking water source than in villages using both artesian and shallow wells, and even greater than in villages using shallow wells only.

Aged↗

The stability of prostatic acid phosphatase, as measured by a capture immunoenzyme assay.

A capture immunoenzyme assay (CIEA) for prostatic acid phosphatase (PAP) was developed and used to study the stability of this isoenzyme. Immunospecifically purified goat antibodies to PAP were covalently bound to special discs and used to capture the enzyme in serum samples in a weakly acidic medium during the first incubation (2 h) at 37 degrees C. The capture enzyme was then measured by its catalytic activity with p-nitrophenyl phosphate as substrate during the second incubation (1 h) at 37 degrees C. As much as 98% of the PAP in test specimens was captured and measured by this CIEA. The test results were expressed as enzymatic activity (U/l), extrapolated from a standard curve which was linear between 0.026 and 70 U/l. In test sera stored at 4 degrees C, the PAP was variably stable for 7 to 70 days, but the enzyme was quite stable in serum when stored at -20 degrees C for at least 156 days. At room temperature, when the sera were appropriately acidified, there was no loss of enzymatic activity for periods of 15 days, and in some cases, a large proportion of activity was still intact after 70 days. At 4 degrees C, as well as -20 degrees C, acidified serum and the partially purified PAP standard showed complete stability for at least 7 months. The CIEA reactivity of positive test specimens was inhibited by L(+)-tartaric acid, but not by cupric sulfate. The acid phosphatases of blood cell extracts were non-reactive in the CIEA procedure. The CIEA results of 224 serum samples from patients with and without prostate cancer correlated very well with those obtained by two direct enzymatic and two commercial RIA procedures, with correlation coefficients between 0.960 and 0.993, and diagnostic agreement between 86% and 100%.

Acid Phosphatase↗

Genetic variance and heritability of cardiovascular risk factors in Chinese adolescent twins.

In order to estimate genetic variance and heritability of systolic blood pressure (SBP), diastolic blood pressure (DBP), serum cholesterol and triglyceride levels, a total of 235 (79 male and 82 female MZ, 41 male and 33 female DZ) twin pairs, recruited from 12 junior high schools in Taipei city, were studied. Statistically significant genetic variance observed for SBP, DBP, serum cholesterol and triglycerides persisted after adjustment for age and anthropometric characteristics. However, further adjustment for dietary preference, beverage consumption, and other host and environmental factors gave different results: genetic variance of adjusted SBP and DBP was still significant, while significance was found only in males for cholesterol and in neither males nor females for triglycerides. Heritability estimates of unadjusted SBP, DBP, cholesterol and triglycerides were 0.27, 0.45, 0.21 and 0.41, respectively, for males, and 0.15, 0.42, 0.41 and 0.82, respectively, for females. After adjustment for age, anthropometric characteristics, host and environmental factors, the heritability estimates of SBP, DBP and cholesterol were 0.64, 0.72 and 0.50, respectively, for males, and 0.40, 0.60 and 0.37, respectively, for females.

Adolescent↗

Environmental effects on cardiovascular risk factors in Chinese adolescent monozygotic twins.

The monozygotic (MZ) cotwin control method was employed to elucidate possible environmental determinants of systolic blood pressure (SBP), diastolic blood pressure (DBP), serum cholesterol and triglyceride levels. A population-based twin sample of 73 male and 77 females MZ twin pairs was recruited from 12 junior high schools in Taipei city. Intrapair differences in blood pressure were negatively associated with intrapair difference in vegetable preference, attaining significance for DBP in males and SBP in females. Cholesterol was positively associated with milk consumption and preference for sweets, fried foods, meat and fish. A negative association was also observed between cholesterol and vegetable preference. These associations for cholesterol were significant in males only. Triglyceride level negatively associated with preferences for sweets and vegetable, attaining significance for vegetables in both males and females and for sweets in males only.

Adolescent↗

Effects of gene-environment interactions on cardiovascular risk factors in Chinese adolescent twins.

A population-based sample of 73 male and 77 female monozygotic (MZ), and 41 male and 33 female dizygotic (DZ) Chinese adolescent twin pairs were studied to assess effects of gene-environment interactions of systolic blood pressure (SBP), diastolic blood pressure (DBP), serum cholesterol and triglyceride levels. Intrapair concordance in BP levels was found to be significantly associated with the interaction of zygosity and salty foods preference and also with that of zygosity and vegetable preference. A consistently positive and statistically significant association was observed between the intrapair difference in serum cholesterol and the interaction of zygosity and animal organ preference; while intrapair concordance in serum cholesterol was associated with the interaction of zygosity and milk consumption. Intrapair difference in serum triglycerides was associated with the interaction of zygosity and fish preference, and a significant association was also found between the intrapair concordance in serum triglycerides and the interaction of zygosity and sweets preference. These observations suggest that the impact of these environmental agents may be influenced by the genotype.

Adolescent↗

Analysis of the secular trend and seasonal variation of measles mortality rate in Taiwan.

The secular trend and seasonal variation of measles mortality rate in Taiwan from 1959 to 1981 were analyzed through multiple regression analyses. A significant downward trend with a regular two-year cyclic fluctuation was observed before and after the implementation of a mass vaccination campaign, and the difference between odd and even years was greater in later years than in earlier years. There was a characteristic unimodal pattern of seasonal variation which peaked in the months of late spring or early summer, and measles deaths were found more clustered in epidemic years than in nonepidemic years. While 94.3% of the total variation of annual measles mortality rate could be explained by calendar year, two-year cycle, and their interaction; 87.6% of the total variation of monthly measles mortality rate could be explained by calendar year, two-year cycle, month, and the interaction between two-year cycle and month. The implication and application of such multiple regression analysis of temporal components of measles epidemiology are discussed.

Child↗

Epidemiological aspects of a poliomyelitis outbreak in Taiwan, 1982.

Active surveillance was carried out to examine the epidemiological characteristics of an abrupt outbreak of poliomyelitis after a significant decline in incidence had resulted from a mass vaccination campaign. Through the intensive survey of private and public hospitals, a total of 1,058 paralytic cases were found with a sex ratio of 1.4. While the age-specific attack rate was highest for the age group of less than one year and decreased with increasing age, the age composition did show a greater proportion of higher age groups than in previous outbreaks. Among 901 cases with a known history of vaccination, about half had received no vaccination and only 9.7% had received three or more doses. The outbreak started on May 29th, peaked in late August and ended on November 1st. The epidemic spread from the north through the middle to the south of the island during this period. A simulated epidemic curve based on the Reed-Frost model fitted the observed one fairly well. Attack rates varied from county to county and were significantly associated with the community health status, vaccination coverage, and their interaction. Possible ways to prevent the epidemic are discussed.

Adolescent↗