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Biomedical subjects

T Kawabata

Publications and source records attributed to T Kawabata.

At least 163 records · Page 9Linked to original sources
PubMed1984

Analysis and occurrence of total N-nitroso compounds in the Japanese diet.

A quantitative technique for differentiating the total N-nitrosamides from the total N-nitroso compounds has been devised. The principle of this method is based on the chemiluminescence response of a nitroso compound under different denitrosating conditions. We also examined the effect of nitrite scavengers on the stability of N-nitroso compounds and found that both ammonium sulfamate and hydrazine sulfate can be satisfactorily used for the detection of chemiluminescence response with hydrogen bromide-acetic acid reagent. A survey of the occurrence of total N-nitroso compounds, total N-nitrosamides, volatile N-nitrosamines, nitrates and nitrites in the Japanese diet has been conducted. Fairly high levels of total N-nitroso compounds were detected in salt-fermented vegetables, the highest being 2 500 micrograms/kg in hakusai-zuke (salt-fermented Chinese cabbage), followed by 253 micrograms/kg in takuan (salt-fermented radish roots). It is noteworthy that the amounts of total N-nitroso compounds in these products almost coincided with those of total N-nitrosamides, although no appreciable amounts, or only trace quantities, of volatile nitrosamines could be detected in these vegetable products.

Diet↗
PubMed1983

Minimization of inflammation in the treatment of bladder tumors by intravesical instillation of adriamycin.

The purpose of this trial was to minimize local inflammation caused by intravesical instillation of antitumor agents, especially Adriamycin, in the treatment of bladder tumor. Tranexamic acid was chosen as the solvent vehicle for Adriamycin and IV bolus injection of an antiallergic drug, Stronger neo-minophagen C, was given at the time of each instillation. Of 81 cases scheduled for Adriamycin instillation therapy, nine cases (11.1%) dropped out due to severe bladder inflammation, while 17 other cases (21%) experienced local side-effects which were tolerated. Of 62 evaluable cases in whom more than eight instillations were performed, complete regression was observed in six cases (9.7%) and partial regression in 20 cases (32.3%).

Animals↗
PubMed1983

Renal disposition of moxalactam in experimental animals as revealed by stop-flow analysis.

The mechanisms of moxalactam excretion were studied by stop-flow analysis in dogs, monkeys, and rabbits. In dogs, the amount of moxalactam excreted in the urine was almost equal to that estimated by glomerular filtration. There was no specific moxalactam peak corresponding to the p-aminohippuric acid (PAH) peak in the stop-flow patterns of the dogs. The PAH peak disappeared with administration of probenecid, but the moxalactam stop-flow pattern showed no change. In monkeys, no specific moxalactam peak corresponding to the PAH peak could be detected. In the stop-flow pattern of the rabbit, the peak moxalactam concentration corresponded with that of PAH and disappeared with probenecid. These results suggest that in dogs and monkeys renal excretion of moxalactam takes place mostly through glomerular filtration. In rabbits, however, there is a small renal tubular secretory component added to the primary element, glomerular filtration. These observations point to differences in the mechanisms of moxalactam excretion in different animal species.

Animals↗
PubMed1982

Formation of N-nitroso compounds during cooking of Japanese food.

N-Nitrosamines in several traditional Japanese meals, such as 'Nebemono', 'Ten-pura' and Kara-age', were analysed. No appreciable amount, or only trace quantities, of NDMA and NPYR could be detected in these meals. The effects of various gases on nitrosamine formation in dried squid have been examined at higher cooking temperatures and the highest yield of NDMA was observed by exposure to the gas produced by the combustion of kerosene, followed by that of city gas, while very low levels of NDMA were formed when samples were wrapped in aluminium foil or broiled in air or argon atmospheres. The principal precursor of NDMA in dried squid was found to be TMAO, which is abundant in the squid muscle and from which nitrosatable DMA can be produced during broiling at higher temperatures.

Cooking↗
PubMed1980

Occurrence, formation and precursors of N-nitroso compounds in the Japanese diet.

A survey has been made of volatile nitrosamines in 123 fermented foods. These included salt-fermented vegetables, soy sauce, "miso", Japanese "sake" and other fermentation products. No appreciable amount, or only trace quantities, of NDMA and NPYR were detected in vinegar, "sake", wines and whiskies, while minute quantities of NDMA were detected in 31 out of 33 beer samples, where the levels ranged from traces to 13.8 micrograms/l, with an average of 5.1 micrograms/l. The nitrosamine content of salt-dried fish apparently increased when these products were broiled in a city gas range. A method for the determination of N-alkylureas in foods has been developed. A total of 57 food samples, both uncooked and broiled in a gas range or fried, were analysed. No alkylureas could be detected in these samples.

Animals↗
PubMed1979

Gas chromatographic separation of hydroxylated N-nitrosamines.

Derivatives of six hydroxylated N-nitrosamines were prepared by acylation, trifluoroacylation, trimethylsilylation and methylation, and the volatilities and sensitivities of these derivatives on gas chromatographic detection were compared. All six nitrosamines were successfully derivatized by either acylation or trimethylsilylation. The acylated derivatives were easy to prepare; in addition, acylation was more specific than trimethylsilylation for the reaction with hydroxyl groups in the molecule.

Acylation↗
PubMed1979

[Results of the special physical examination of workers in a vanadium plant (author's transl)].

Special physical examinations were made in order to find out the actual status of damages to health that had broken out in a factory collecting V2O5 from iron sand; and the following results were found: 1. Pharyngitis and bronchitis were found in 25% of the workers exposed to vanadium, but neither pneumonia nor hepatitis was observed. 2. Among the subjective and objective symptoms, respiratory irritation and discoloration of the tongue were frequent. 3. Black spot-like pigmentations gathering in a zonal form 1-2 mm wide in the transitional part and oral mucosa of the upper lip were found. Prevalence rate of this sign was 14.3% in the workers exposed to vanadium. 4. The mean valus of total serum protein and the serum cholesterol in the exposed workers were lower than those in the controls. The difference in the values between both groups is statistically significant. 5. Both the mean values of vanadium concentrations in vurine and its creatinine ratios in the exposed workers were twice to three times those in the controls; however, these parameters decreased to about one third in two months by improving the health and environmental control-measures. 6. Draft items to be checked in special physical examinations of workers handling vanadium have been proposed.

Environmental Exposure↗
PubMed1979

[Fundamental studies and clinical evaluation of PC-904 in urinary tract infection (author's transl)].

Measurement of MICs of PC-904, CBPC and GM against 135 strains of Pseudomonas aeruginosa isolated from patients with urinary tract infections was performed. Susceptibility to PC-904 of Pseudomonas aeruginosa was found to be 3 approximately 7 times more sensitive than that to CBPC and as same as that to GM with inoculum size of 10(8)/ml and 10(6)/ml. Serum level of PC-904 reached a peak of 38.5 microgram/ml 15 minutes after 0.5 g intravenous administration. Urinary recovery rate unit 6 hours after the administration was 12.5%. Overall clinical efficacy of 6 cases of acute simple cystitis and 3 cases of chronic complicated cystitis was judged to be 83.3% and 33.3% respectively by a criterion proposed by the UTI Committee in Japan.

Adult↗
PubMed1978

Mechanism of N-nitrosodimethylamine formation from trimethylamine and trimethylaminoxide.

The kinetics of nitrosation of trimethylamine (TMA) and trimethylaminoxide (TMAO) to give N-nitrosodimethylamine (NDMA) have been studied. The nitrosation rates of TMA and TMAO, when determined at 100 degrees C in sealed tubes, showed maximum values at about pH 3, while at temperatures lower than 75 degrees C the pH dependence of the nitrosation of these compounds was similar to that observed with alkylamides. The initial rate of NDMA formation from TMAO determined at pH 3.0 and 25 degrees C was found to be proportional to the TMAO and nitrite concentrations, not to the square of the nitrite concentration. In contrast, the rates of NDMA formation from TMA and TMAO when reacted at pH 3.0 and 100 degrees C in sealed tubes were found to be proportional to the square and the cube, respectively, of the nitrite concentration. These results strongly suggest that the NDMA formation at higher temperatures involves the oxidative cleavage of tertiary amines to produce secondary amines (dimethylamine, DMA) which may react with nitrite to form NDMA. On the other hand, at lower temperatures, NDMA may be formed from TMA or TMAO by a pathway not involving DMA.

Chemical Phenomena↗
PubMed1978

Occurrence of methylguanidine and agmatine in foods.

Methylguanidine (MG), a precursor of carcinogenic methylnitrosocyanamide and methylnitrosourea, has long been considered to occur widely in fresh beef and various fish muscles in fairly high concentrations. Agmatine (AG) has been reported to be easily nitrosated to give a potent mutagen under acidic conditions. A survey has been conducted on the MG and AG contents of various fresh and processed foods. The present study reveals that no appreciable amount, or only trace amounts, of MG could be detected in fresh beef, pork, chicken and various fish and shellfish. In addition, almost the same low levels of MG were detected in various processed foods, except in the case of smoked-dried fish products, where the MG values ranged from 18 to 178 mg/kg. Relatively high concentrations of AG, ranging from 40 to 200 mg/kg, could be detected in fresh abalone and top-shell muscles, while fairly high concentrations of AG could be detected in some processed foods. A dried squid product, in particular, was found to contain as high as 650 mg/kg of AG.

Agmatine↗