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Biomedical subjects

T Shibamoto

Publications and source records attributed to T Shibamoto.

144 records · Page 8Linked to original sources
PubMed1982

Genotoxicity of safrole-related chemicals in microbial test systems.

The genotoxicity of safrole, 9 compounds that are structurally similar to safrole (anethole, cinnamaldehyde, cinnamyl alcohol, estragole, methyl eugenol, eugenol, isoeugenol, isosafrole, piperonal), 5 essential oils, cassia oil, cinnamon bark oil, clove oil, fennel oil) which contain the chemicals tested, and 1 oleoresin was studies in 3 microbial test systems. Only anethole showed mutagenicity in the Ames Salmonella reversion assay. All chemicals except anethole, estragole and isosafrole were positive in the Bacillus subtilis DNA-repair test (Rec assay) without S9. All samples tested were negative in the Escherichia coli WP2 uvrA reversion test. The essential oils and pimenta oleoresin were positive in the DNA-repair test. The results obtained are discussed in relation to the nature of the problems encountered with each test method.

1-Propanol↗
PubMed1982

Mutagenicity of the products obtained from heated milk systems.

Methylene chloride extracts of the browning reaction products prepared from model systems consisting of major milk components (casein and/or lactose, and non-fat dried milk) were tested for mutagenicity in the Ames Salmonella/microsome assay. Samples obtained by heating aqueous solutions of these components under either neutral or basic (pH 10) conditions exhibited no significant mutagenic activity when tested with or without S-9 mix. The addition of common food additives, such as sodium nitrite, butylated hydroxyanisole and butylated hydroxytoluene, to the aqueous solutions did not enhance the mutagenic activity of the browning samples. On the other hand, the tar samples prepared by heating the same milk components in the dry state exhibited strong mutagenicity, primarily to Salmonella typhimurium strain TA98 and only with S-9 mix. A casein/lactose mixture and non-fat dried milk were also heated with baking soda in the dry state. The presence of the baking soda enhanced the mutagenicity of the browning products; the tar from the non-fat dried milk heated with baking soda was the most potently mutagenic of all the samples towards strain TA98 and also produced a positive response in strain TA100 in the presence of S-9 mix.

Animals↗
PubMedDate not supplied

Gas chromatographic determination of vapor-phase biomarkers formed from rats dosed with CCl4.

Sprague-Dawley rats dosed with CCl4 (3 ml kg-1) were placed in a glass chamber through which air was passed continuously at a rate of 60 ml min-1. Volatile aldehydes and ketones in expired air from rats were derivatized to thiazolidines by passing the effluent gas stream through an aqueous cysteamine solution. The thiazolidine derivatives were then extracted and analyzed by gas chromatography with a nitrogen-phosphorus detector and gas chromatography/mass spectrometry. The compounds identified were formaldehyde, acetaldehyde, acetone and formyl chloride. There were no appreciable differences in levels of formaldehyde and acetaldehyde between CCl4-dosed rats and control rats, whereas the levels of acetone in CCl4-dosed rats showed an increase compared to those in control rats. Results suggest that acetone is the major volatile carbonyl compound produced following acute doses of CCl4. Results of thiobarbituric acid assay on the livers from a control rat and a CCl4-dosed rat did not show any appreciable differences.

Acetaldehyde↗
PubMedDate not supplied

Determination of free malonaldehyde formed in liver microsomes upon CCl4 oxidation.

Free malonaldehyde formed in the microsomes prepared from livers of monkey, rat, rabbit, mouse, cow, pig, dog, sheep and horse upon CCl4 oxidation was derivatized by reaction with N-methylhydrazine to form 1-methylpyrazole which was subsequently analyzed by capillary gas chromatography. Among the livers from animals tested, the monkey and rat livers produced the most malonaldehyde upon CCl4 treatment. Horse liver showed the greatest resistance to CCl4 oxidation. The gas chromatography method used in the present study exhibited an accurate and specific measurement of free malonaldehyde that might provide an understanding of the biochemical process of in vitro lipid peroxidation.

Animals↗
PubMedDate not supplied

Chromatographic determination of dicofol and metabolites in egg yolks.

Egg yolk was spiked with p,p'-dicofol (p,p'-DCF) (0.1-2.0 micrograms/gm), p,p'-dichlorobenzophenone (p,p'-DCBP) (0.1-2.0 micrograms/gm), and 1,1-bis(4-chlorophenyl)-2,2-dichloroethylene (p,p'-DDE) (0.05-1.0 micrograms/gm). The fortified egg yolk (2-5 g) was mixed with acetonitrile to extract non-fat organic materials. After removal of acetonitrile, the spiked chemicals were separated with a column chromatograph packed with acid alumina. Recovery efficiencies for p,p'-DCBP and p,p'-DDE were determined by gas chromatography, and for p,p'-dicofol by high performance liquid chromatography. The recovery efficiencies for p,p'-dicofol, p,p'-DCBP and p,p'-DDE were 77.2-93.8%, 84.1-101.1%, and 88.5-96.0%, respectively.

Animals↗
PubMedDate not supplied

Formation of malonaldehyde in the presence of probucol, an anti-atherosclerosis drug.

Formation and inhibition of malonaldehyde (MA) from blood plasma lipids oxidized by Fenton's reagent in the absence or presence of probucol [4,4'-(isopropylidenedithio)bis(2,6-di-tert-butylphenol)] and L-ascorbic acid were investigated. The amount of MA formed was quantitatively analysed by gas chromatography. L-Ascorbic acid inhibited MA formation by about 30% at the level of 4.0/micromol, but the amount of MA formed was increased by the presence of probucol. When 3.0 micromol oxidized probucol was hydrolysed at pH 1. 3 and 5, 2616.5 nmol, 287.5 nmol and 103.9 nmol MA were recovered, respectively. This is the first report of quantitative analysis of MA formed from probucol on oxidation.

Animals↗
PubMedDate not supplied

Effect of ONO-5046, a specific neutrophil elastase inhibitor, on the phorbol myristate acetate-induced injury in isolated dog lung.

Phorbol myristate acetate (PMA) activates neutrophils and causes acute lung injury. We determined the effect of ONO-5046, a specific neutrophil elastase inhibitor, on the increase in microvascular permeability induced by PMA in isolated dog lung perfused with autologous blood at a constant perfusion flow. The vascular permeability was assessed by the capillary filtration coefficient (Kf, c) and the solvent-drag reflection coefficient (sigma f). PMA (13.3 micrograms) increased vascular permeability, as evidenced by an increase in Kf, c from 0.18 +/- 0.02 to 0.92 +/- 0.14 mL/min/cmH2O/100 g and a decrease in sigma f to 0.35 +/- 0.01 as compared to control values of 0.69 +/- 0.06. The PMA-induced changes in Kf, c and sigma f were dose-dependently attenuated by pretreatment with ONO-5046 (2-20 mg). We conclude that ONO-5046 can effectively attenuate the PMA-induced injury in the isolated blood-perfused dog lungs.

Animals↗
PubMedDate not supplied

Gas chromatographic method for determination of chlorpyrifos and its metabolite 3,5,6-trichloro-2-pyridinol (TCP) in dates.

A method is described for the determination of the insecticide chlorpyrifos and its metabolite TCP in green, unprocessed, and processed dates with the seeds incorporated. After extraction, chloropyrifos is cleaned up using Florisil and analyzed using a gas chromatography (GC) equipped with a nitrogen/phosphorus detector. TCP is derivatized using bis-(trimethylsilyl)-acetamide (BSA) to form the TCP-derivative and analyzed by a gas chromatograph equipped with a Hall electrolytic conductivity detector. Recoveries of chlorpyrifos from all fortified dates (0.05 and 0.1 ppm) ranged from 86 to 110% with an average of 94.5%. Recoveries of TCP from all fortified dates (0.1 and 0.2 ppm) ranged from 79 to 99% with an average of 86%. Limits of detection for chlorpyrifos and TCP in green, unprocessed, and processed dates were 0.02 and 0.05 ppm, respectively.

Chlorpyrifos↗
PubMedDate not supplied

Formaldehyde quantitation in air samples by thiazolidine derivatization: factors affecting analysis.

A new method for the determination of trace levels of formaldehyde in air was developed and validated. The method is based on the reaction of formaldehyde with cysteamine to form thiazolidine. Air samples containing trace levels of formaldehyde were prepared from paraformaldehyde. The percent yield of formaldehyde from paraformaldehyde was 85.1 +/- 1.14%. Air samples were bubbled into an aqueous cysteamine trap. Thiazolidine formed from formaldehyde and cysteamine in the trap was determined by gas chromatography with a fused silica capillary column and a nitrogen-phosphorus detector (NPD). The lowest detection level for thiazolidine was 17.2 pg, equivalent to 5.80 pg formaldehyde. The recovery efficiency of trace gas phase formaldehyde in air was greater than 90%. Formaldehyde levels in ambient laboratory air were 48.9-56.2 ppb (v/v).

Air↗
PubMedDate not supplied

Development and validation of new analytical method for acrolein in air.

A new method was developed to determine vapor-phase acrolein in air samples. Air containing vapor-phase acrolein was purged into impingers filled with a dichloromethane solution of N-methylhydrazine. The resulting derivative, 1-methyl-2-pyrazoline, was analyzed by gas chromatography using a nitrogen-phosphorous detector (NPD). The detection limit was 8.9 pg 1-methyl-2-pyrazoline, equivalent to 5.9 pg acrolein. The recovery efficiencies of vapor-phase acrolein were 98.0 +/- 2.9% and 100.3 +/- 3.1% for 150 and 15 micrograms, respectively. This method was satisfactorily applied for determination of acrolein formed from various heated fats. The amounts of acrolein formed in a headspace were 109 micrograms/L from lard, 164 micrograms/L from corn oil, 5.1 micrograms/L from cotton seed oil, and 163 micrograms/L from sunflower oil.

Acrolein↗
PubMedDate not supplied

Gas chromatographic determination of formaldehyde in coffee via thiazolidine derivative.

Thiazolidine formed from trace quantities of formaldehyde in an aqueous solution containing cysteamine at pH 8 was extracted with chloroform and subsequently analyzed by a gas chromatograph equipped with a fused silica capillary column and a thermionic nitrogen-phosphorus specific detector. Recoveries of formaldehyde from the aqueous solutions at levels lower than 1 ppm were slightly over 100%. Quantitative analysis of formaldehyde in commercial brewed and instant coffees showed 3.4-4.5 ppm in the brewed and 10-16.3 ppm in the instant coffee.

Aldehydes↗