Biomedical subjects

Tadashi Sakai

Publications and source records attributed to Tadashi Sakai.

21 records · Page 2Linked to original sources

PubMed2002

Biological monitoring of workers exposed to dichloromethane, using head-space gas chromatography.

A biological monitoring method for urinary dichloromethane (DCM) has been developed by using head-space gas chromatography with FID detection. The calibration curve is linear in a wide range of DCM levels between 0.01 and 2 mg/l. The recovery rate is almost 100% and within-run coefficients of variation are 2.9-3.7%. A highly significant correlation is found between exposure levels and urinary concentrations of DCM. Determination of urine DCM by this method has many advantages such as sample storage, no need for correction of urine concentration, absence of gender difference and also no confounding effect of glutathione S-transferase T1 polymorphism.

Chromatography, Gas↗

PubMed2002

LC-MS determination of urinary toluenediamine in workers exposed to toluenediisocyanate.

To improve the biological monitoring method for 2,6- and 2,4-toluenediisocyanate (TDI) exposure, we developed a simple and rapid method for analysis of the corresponding urinary metabolites, 2,6- and 2,4-toluenediamine (TDA) using liquid chromatograph-mass spectrometry (LC-MS). One ml of urine was hydrolyzed at 100 degrees C for 1.5 h with H(2)SO(4). Alkalinized hydrolysate was extracted with dichloromethane (DCM) and analyzed by atmospheric pressure chemical ionization (APCI) LC-MS, in positive-ion mode. The mass spectra of TDA isomers showed the protonated molecule [M+H](+), at m/z 123 as the base peak. Calibration curves of 2,6-TDA were linear up to 400 microg/l. TDA isomers in urine of exposed workers as determined by LC-MS correlated well with those obtained by gas chromatography-mass spectrometry. 2,6- and 2,4-TDA were not detected in non-exposed subjects, whereas exposed workers showed urinary levels up to 250 and 63 microg/l, respectively.

Chromatography, Liquid↗

PubMed2002

Bacillus funiculus sp. nov., novel filamentous isolates from activated sludge.

A novel filamentous Bacillus strain, NAF001T, was reported previously that produces endospores and spore-like resting cells; the latter outgrow by budding. Phylogenetic analysis based on 16S rDNA gene sequences reported in the same paper speculated on the proposal of a novel species for this isolate. This communication describes the DNA-DNA relatedness of strain NAF001T to various members of the genus Bacillus and its whole-cell fatty acid and quinone profiles, in order to authenticate the creation of a novel species, for which the name Bacillus funiculus sp. nov. is proposed. The type strain is NAF001T (= JCM 11201T = CIP 107128T). Further, features of the binding points between filaments of strain NAF001T that enable it to form extremely long filaments are captured by electron microscopy.

Bacillus↗