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Biomedical subjects

J K Lin

Publications and source records attributed to J K Lin.

At least 181 records · Page 10Linked to original sources
PubMed1989

Anal manometric studies in hemorrhoids and anal fissures.

Manometry study with the use of continuous water perfusion system was performed for 50 patients with Grade III or IV hemorrhoids and for 29 patients with chronic anal fissure. Another 36 patients who did not have any anorectal symptom or pathology were chosen as the control group. The maximal basal pressures for the control, the hemorrhoid, and the chronic anal fissure groups were 71.2 +/- 24.9, 85.3 +/- 27.7 and 87.4 +/- 38.8 mmHg respectively; the maximal contraction pressures for the control, the hemorrhoid and the fissure groups were 132.9 +/- 44.9, 158.8 +/- 58.0 and 162.1 +/- 64.5 mmHg; while the lengths of the functional sphincter of the three groups were 3.7 +/- 0.5, 3.8 +/- 0.8 and 3.9 +/- 0.6 cm respectively. The maximal basal pressures and the maximal contraction pressures of the hemorrhoid and fissure patients were significantly greater than those of the control group; whereas the functional sphincter lengths of the three groups did not show significant difference.

Adult↗
PubMed1989

Evaluation of rapid colon preparation with Golytely.

The traditional cleansing method of the large bowel usually involves dietary restrictions, purgatives and enema. They are time consuming and uncomfortable, and may result in dehydration. Though Golytely, an oral lavage solution, has been developed since 1980 as an alternative for cleansing the colon and much literature has favored it, it has not been widely used in Taiwan. In this study, we used Golytely without enema for rapid colon cleansing in a consecutive series of 48 patients. The efficacy, change of vital signs, body weights, electrolytes, and urine specific gravity were evaluated. Patient's acceptance of this method was compared with that of 32 patients who received castor oil as cleansing method. The average amount of Golytely used in this preparation was 3.16 liters, and the average time was 8 hours and 43 minutes. About 87% of patients receiving Golytely achieved a good to excellent preparation. There were no significant changes in vital signs, body weights, electrolytes and urine specific gravity. The patient's acceptance of Golytely was better than that of castor oil.

Colon↗
PubMed1988

A cytogenetic study of mentally retarded school children in Taiwan with special reference to the fragile X chromosome.

A cytogenetic study was made on 341 mentally retarded children in the Provincial Nantou Rehabilitation Center for the Mentally Retarded and the St. Raphael Opportunity Center in Tainan. Of the 89 mentally retarded children with chromosomal abnormalities, 63 had Down syndrome, 13 had the fragile X [fra(X)] syndrome, and the remaining had other aneuploid constitutions. Family studies were possible for 2 of the 13 fra(X) probands. The results of this study illustrate the contribution of chromosomal abnormalities to the pathogenesis of mental retardation in children.

Chromosome Banding↗
PubMed1988

Suppression of the growth of human colorectal carcinoma cells (LS174T) by radiolabeled monoclonal antibody (131I-MAbC27) in tissue culture and nude mice.

A monoclonal antibody against carcinoembryonic antigen (CEA), MAbC27, and its F(ab')2 fragments were prepared and labeled with 131I. They effectively suppressed the growth of a human colorectal carcinoma cell line, LS174T, both in culture medium and in inoculated nude mice, whereas 131I-labeled normal mouse immunoglobulin or 131I itself did not have similar effects. Intravenous injection of 131I-MAbC27 or 131I-MAbF(ab')2 following inoculation of carcinoma cells suppressed their growth in vivo. The suppression effect was even more effective when intact antibody rather than its F(ab')2 fragments was used, especially when the treatment was repeated. This study indicates that radiolabeled MAbC27 may be used as a therapeutic agent in CEA-secreting human colorectal carcinomas.

Animals↗
PubMed1988

N-nitroso-N-2-fluorenylacetamide: a new direct-acting mutagen and teratogen.

Reaction of N-2-fluorenylacetamide (2-FAA, CAS No. 53-96-3) with nitrous fume (N2O3) in glacial acetic acid at 0 degree C yields N-nitroso-N-2-fluorenylacetamide (N-NO-2-FAA), 3-nitro-N-2-fluorenylacetamide, N-nitroso-3-nitro-N-2-fluorenylacetamide and other compounds. N-NO-2-FAA is the major product (80%) and fairly stable at low temperature (-20 degrees C), but extremely labile at ambient temperature. The chemical structure of N-NO-2-FAA is characterized by spectrometric analysis of its naphthol coupling derivatives. This new compound is highly mutagenic to Salmonella typhimurium TA97, TA98, TA100 and TA1538 and requires no microsomal metabolic activation. The mutagenicity of N-NO-2-FAA in TA98 is higher than that of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG, CAS No. 70-25-7) and N-acetoxy-N-2-fluorenylacetamide (N-AcO-2-FAA). The teratogenic potential of N-NO-2-FAA was studied with white Leghorn chick embryos given a single dose of 1-100 micrograms/egg on day 6 of incubation. A high incidence of flaccid paralysis of the legs and a low incidence of feather, claw and bill malformations were found in the treated group; no such malformed embryos were found in the control group. The teratogenicity of N-NO-2-FAA was found to be weaker than that of MNNG, but comparable to that of N-methyl-N-nitrosourea (CAS No. 684-93-5). N-NO-2-FAA is a strong electrophile and reacts readily with histidine, lysine, cysteine, glutathione, tryptophan, adenosine, cytidine at neutral pH. In contrast to N-AcO-2-FAA, N-NO-2-FAA does not react significantly with guanosine and thymidine. It seems that N-NO-2-FAA is a strong direct-acting mutagen and probably a new prototype of synthetic carcinogen.

2-Acetylaminofluorene↗
PubMed1986

Protection of crocin dyes on the acute hepatic damage induced by aflatoxin B1 and dimethylnitrosamine in rats.

Chemopreventive agents are compounds that inhibit carcinogenesis when administered prior or subsequent to a course of carcinogen administration. The effects of dietary administration of crocin dyes on the hepatic damage induced by aflatoxin B1 (AFB1) and dimethylnitrosamine (DMN) in rats were investigated. Female Sprague-Dawley rats were treated with different dosages of AFB1 (0.9 or 4.5 mg/kg) or DMN (8 or 20 mg/kg) by i.p. administration, and the different degrees of hepatic damage were revealed by the elevations of levels of serum marker enzymes such as aspartate amino-transferase, alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transpeptidase and lactic dehydrogenase. Pre-treatment of the animals with crocin dyes 50 mg/kg daily for three consecutive days, the enzyme elevations were significantly suppressed. This suggested that the crocin dyes possessed chemopreventive effects on the early acute hepatic damage induced by AFB1 or DMN. Feeding experiments demonstrated that crocin dyes at 0.1% in the diet could suppress partially the chronic hepatic damage induced by multiple dosages of AFB1 or DMN, but at a higher concentration of 1% crocin dye failed to do so because of their host toxicity. Crocin dyes are extracted from the fruits of Gardenia jasminoides and consist of carotenoids and geniposides as active principles. The protective mechanisms of crocin dyes may be attributed to their carotenoids which are converted metabolically to retinoids in rats.

Aflatoxin B1↗
PubMed1986

Mutagenicities of nitrosated carboline derivatives.

Food-borne amines have been considered as the potential precursors of endogenous carcinogenic N-nitroso compounds in humans. A compound which yields a direct mutagen after nitrite treatment was isolated from soy sauce and was identified as 1-methyl-1,2,3,4-tetrahydro-2-carboline-3-carboxylic acid (MTCA) (Wakabayashi, et al., 1983). The mutagenicities of other carboline derivatives such as harman, norharman, harmaline, harmalol, harmine, and harmol were studied. Like MTCA, the nitrosated carboline derivatives showed higher mutagenic activity as compared to their corresponding parent compounds. The demethylated analogue of MTCA, 1,2,3,4-tetrahydro-2-carboline-3-carboxylic acid was synthesized and its nitrosated products were shown to be mutagenic to Salmonella typhimurium TA 100 and TA 98. The potent mutagen Trp-P-2 is a typical 3-carboline derivative. The mutagenicity of Trp-P-2 was suppressed remarkably after nitrosation. Several 3-carboline derivatives also showed the similar property. Nitrosation of MTCA gave several derivatives which were isolated and showed direct mutagenicity to Salmonella typhimurium TA 98. Further characterization of these new carboline derivatives is in progress.

Carbolines↗
PubMed1986

Food-borne amines and amides as potential precursors of endogenous carcinogens.

This paper reviews the experimental results of our research in the past several years and other related papers that have been directed toward the occurrence, biotransformation and epidemiological significance of carcinogenic N-nitroso compounds in biosphere. Endogenous carcinogens are a group of cancer-causing compounds produced in vivo from harmless precursors. This category has been exemplified by the well-known carcinogens, N-nitroso compounds. The significance of naturally occurring amines and amides as precursors of carcinogenic N-nitroso compounds in vivo and their implication in the incidence of human cancer have been investigated and emphasized. Extremely high levels of trimethylamine-N-oxide and dimethylamine were detected in squids and other seafoods. More than 90% of trimethylamine-N-oxide were converted to dimethylamine and trimethylamine on pyrolysis. Low levels of dimethylamine and methylamine were also detected in the fermented soybean products, wines and sauces. Both dimethylamine and trimethylamine are excellent precursors of dimethylnitrosamine. Several naturally occurring aromatic amines especially 2-carboline derivatives such as harman, norharman, harmaline, harmalol, harmine and harmol are mutagenic and become more mutagenic to Salmonella typhimurium after nitrosation. Appreciable amounts of piperidine were detected in the popular spice white and black pepper powders. Under acidic condition, piperidine reacts readily with nitrite to form carcinogenic N-nitroso-piperidine. N-Nitrosophenacetin was formed from the reaction of nitrite with the amide drug phenacetin. This new compound showed strong mutagenicity to Salmonella typhimurium and Sarcina lutea and strong teratogenic activity to Leghorn chicken embryos. Studies have shown that the majority of N-nitroso compounds in the body come from in vivo conversion. Most investigators believe that this endogenous pool of N-nitroso compounds may prove to be a major exposure route in man. The presence of naturally occurring amines and amides in the diet then becomes one of the crucial limiting steps in the formation of endogenous N-nitroso compounds in vivo.

Amides↗
PubMed1985

Thermal conversion of trimethylamine-N-oxide to trimethylamine and dimethylamine in squids.

The levels of dimethylamine-nitrogen (DMA-N), trimethylamine-nitrogen (TMA-N) and trimethylamine-N-oxide-nitrogen (TMAO-N) were determined in five species of dried squid. Each sample contained extremely high levels of TMAO-N (2558-8064 ppm) and moderate amounts of TMA-N (121-503 ppm) and DMA-N (124-373 ppm). Over 90% of TMAO-N in squid was converted to TMA-N and DMA-N after heating at 200 degrees C for 1 hr; approximately 50% of the volatile TMA-N and DMA-N was lost during the course of the heating. The thermal conversions were accelerated by heat, and possibly involved catalysis by certain tissue constituents. Squids are a popular seafood in most oriental countries, but before appearing on the market they are subjected to a long food-processing procedure. Therefore, a high concentration of TMAO in squids is an important problem, for food technology as well as toxicology.

Animals↗
PubMed1985

Effect of severe injury and critical illness on high-energy phosphates in human liver and muscle.

Changes in hepatic and muscle high-energy phosphates in varying degrees of resting hypermetabolism were studied. Fourteen severely injured and five critically ill patients with normal blood pressure were investigated: the results were compared with 14 normal controls. ATP and ADP levels in the muscle were significantly changed in acutely severe injury: lactate and pyruvate levels in the liver and muscle increased; glycogen level in the liver decreased. Meanwhile, high-energy phosphates in both liver and muscle were not significantly changed in ongoing severe injury. Lactate level increased and glycogen level decreased in both tissues. In critical illness, hepatic and muscle ATP and ADP decreased significantly. The energy charge potential dropped. AMP, lactate, and the lactate-to-pyruvate ratio increased. Hepatic, but not muscle, glycogen dropped markedly. The correlation coefficient between hepatic and muscle ATP was 0.61; between hepatic ATP and hepatic glycogen was 0.60. Alteration in the ATP-ADP-AMP system in the liver and muscle suggests a low-energy charge in acute, severe injury and critical illness. This indicates a decreased capacity for biosynthetic reactions and production of storage compounds. The changes in high-energy phosphate in the liver always paralleled similar changes in muscle.

Adult↗