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T Mio

Publications and source records attributed to T Mio.

82 records · Page 5Linked to original sources
PubMed1987

Use of GC/MS/SIM for rapid determination of plasma levels of o,p'-DDD, o,p'-DDE and o,p'-DDA.

A new method for extraction and quantification of plasma o,p'-DDD (2,2-(2-chlorophenyl,4'-chlorophenyl)1,1-dichloroethane) and its metabolites has been developed. When plasma (0.1 ml) adsorbed to and dried on a filter paper was heated with 5% hydrogen chloride in methanol (1 ml) in a boiling water bath, o,p'-DDD and its metabolites were liberated from the serum protein and were able to be easily extracted with benzene. The recovery rate was raised compared with conventional methods. In addition, this procedure also carried out the simultaneous methylation of o,p'-DDA, one of the metabolites. Mass numbers of 199, 210, 235 and 246 were selected from the mass spectra of o,p'-DDD and its related substances, and they were monitored. Identification was performed on the basis of the retention time and the mass peak intensity ratio. Quantitative determination was performed using the internal standard technique. It was learned that o,p'-DDA is present in the plasma at a concentration about 10 times higher than the levels of o,p'-DDD and o,p'-DDE.

Circadian Rhythm↗
PubMed1986

A simple method to diagnose adrenoleukodystrophy using a dried blood spot on filter paper.

A new, simple method for the diagnosis of adrenoleukodystrophy (ALD) using a dried blood spot sample, is described. Fatty acid from the dried blood spot was extracted and methylated simultaneously with HCl-methanol. Fatty acid methyl esters were analyzed by gas chromatography-mass spectrometry. Fatty acid compositions of the blood spot from four patients with ALD and five healthy controls were determined from the mass chromatograms of the m/z 143 ion, [(CH2)6 COOCH3]+. The ratios of tetracosanoic acid to docosanoic acid (C24:0/C22:0) and hexacosanoic acid to docosanoic acid (C26:0/C22:0) were significantly greater in ALD patients than in the controls. The fatty acid composition of the dried blood spot did not change at room temperature within a week. Since the specimens can be sent by mail, this method could be applied to the screening of ALD.

Adrenoleukodystrophy↗
PubMed1985

Mechanism of biosynthesis of methylsulfones from PCBs and related compounds.

Mercapto-, methylthio-, methylsulfinyl- and methysulfonyl metabolites of PCBs 2,5,2',5'-tetrachlorobiphenyl, 1,3,5-trichlorobenzene and some other chlorobenzenes were identified in adipose tissues of mice, rats and guinea pigs by using GC/MS/COM systems. By means of administration of CD3-methionine, it was confirmed that the methyl group in methylthio metabolites was derived from the methionine. Moreover, after pretreatment with either esterification of urinary metabolites in guinea pigs with 1,3,5-trichlorobenzene and 1,3-dichlorobenzene or N-acetylation after esterification, it was confirmed that cysteinylglycine, cysteine, N-acetylcysteine, cysteamine, mercaptopyruvate, mercaptolactate, mercaptacetate, thiol and disulfide conjugates were detected as a serial modified derivatives of glutathione moiety. These results are summarized as a metabolic proposed pathway of halogenated aromatic compounds. Three routes in pathway correspond to oxygenation (initial route), glutathione thioether disposition (intermediate route) and sulfoxydation (final route) in connection with both reactive intermediates of epoxide and thiol. Methylation of the thiol by S-adenosylmethionine may be important in inhibiting covalent binding of reactive intermediates with biocomponents, similar to the glutathione conjugation for the detoxification of epoxide.

Animals↗
PubMedDate not supplied

Regulation of fibroblast proliferation in three-dimensional collagen gel matrix.

Fibroblasts in vivo reside in a three-dimensional (3-D) matrix. The 3-D culture method using collagen gels provides valuable information, but it also has some practical difficulties. In particular, the changes caused by the contraction of gels and the occasional abrupt detachment from the underlying surface have made extended culture difficult. In this study, the 3-D culture method was modified in order to observe the cells with minimal change of substrata for longer periods. The proliferation characteristics of fibroblasts cultured in gels in response to fetal calf serum (FCS), to two defined growth factors, insulin and platelet-derived growth factor (PDGF), and to a growth inhibitory factor, prostaglandin E2 (PGE2), were evaluated with this system in comparison with monolayer cultured fibroblasts. The DNA content of fibroblasts cultured both in gels and on dishes increased in response to FCS in a concentration-dependent manner. The proliferation of gel-cultured fibroblasts, however, was lower than that of dish-cultured cells, and higher concentrations of serum were necessary for proliferation. The response of gel-cultured cells to PDGF was also less than that of dish-cultured cells. In addition, fibroblasts cultured in gel culture did not respond to insulin, while the fibroblasts on dishes responded to insulin in a concentration-dependent manner. In contrast to the reduced response to growth stimulators, PGE2 inhibited proliferation in gel culture and in monolayer culture similarly. The reduced responsiveness to growth stimulation but equivalent response to growth inhibition may account for reduced proliferation of fibroblasts in 3-D culture.

Cell Count↗
PubMedDate not supplied

The effect of probucol on oxidized cholesterol disposition in hyperlipidaemic patients.

Probucol is a cholesterol-lowering and antioxidant drug that has been shown to inhibit or delay the progression of atherosclerosis. This antiatherosclerotic effect may result from the removal of oxidized cholesterol on the surface of low-density lipoprotein (LDL). To investigate whether probucol transfers oxidized cholesterol from LDL to urine, urine samples were obtained from five patients with hypercholesterolaemia treated with 500-mg probucol orally daily and from five healthy controls. Using gas chromatography-mass spectrometry, we identified cholesteryl-6-(2,6-di-tertiary butylphenol-4)-thioether (CT) in the urine samples from patients with hypercholesterolaemia but not from healthy controls. This result suggests that probucol is hydrolysed to form 4-mercapto-2,6-di-tertiary butylphenol (MBP) which conjugates with cholesterol-5 alpha, 6 alpha-epoxide, oxidized cholesterol, resulting in the formation of CT in vivo. In addition to its hypolipidaemic and antioxidant actions, probucol may act to prevent atherosclerosis by increasing the urinary excretion of oxidized cholesterol.

Anticholesteremic Agents↗
PubMedDate not supplied

Metabolism of o,p'-DDD in humans: a novel metabolic pathway forming methylthio-containing metabolites.

Urine samples were obtained from four patients with Cushing's syndrome who had been treated with o,p'-DDD[2,2-(2-chlorophenyl,4'-chlorophenyl)1,1-dichloroethane]. Methylthio-containing (MC) metabolites and other metabolites of o,p'-DDD were detected in the urine samples by gas chromatographic mass spectrometry. These MC metabolites showed smaller peaks in the gas chromatogram than other peaks derived from other metabolites of o,p'-DDD. Although the biological significance of the pathway forming these MC metabolites is not known at present, the mechanism of the metabolic pathway was discussed.

Cushing Syndrome↗