Biomedical subjects

Takahiko Kusakabe

Publications and source records attributed to Takahiko Kusakabe.

4 recordsLinked to original sources

PubMed2004

Validity of plasma remnant lipoproteins as surrogate markers of antemortem level in cases of sudden coronary death.

Hitherto triglycerides (TG) and TG-rich lipoproteins were been of limited value as surrogates for antemortem levels. We measured TG levels in postmortem plasma from sudden coronary death cases (SCD, n=91) by using two TG assays, Dry Chem TG (free glycerol was added) and the Determiner L-TG (without added free glycerol) that measured net TG. TG levels were markedly higher by the Dry Chem TG (y) vs. Determiner L-TG (x), y = 1.03x + 229 mg/dl. HPLC showed large amounts of free glycerol in postmortem plasma and in TG-rich lipoprotein remnants (RLP). These results were verified in a rabbit model of SCD. Further, RLP from SCD were found to be biophysically similar to those from living patients with coronary artery disease (CAD). In conclusion, postmortem plasma sampled up to 12 h after death is appropriate for measuring lipid and lipoproteins, TG and RLP-TG as surrogates for antemortem levels when a TG assay without added free glycerol is used.

Adult↗

PubMed2003

Hippuric acid and methyl hippuric acid in rat hair: possible monitoring of xylene and toluene exposure.

Thinner is mainly composed of toluene and xylenes, and we studied the incorporation of the main metabolites of toluene and xylenes, hippuric acid (HA) and o-, m-, and p-methyl hippuric acids (o-, m-, p-MHA), in dark agouti rats' hair. Rat black hair was shaved before any exposure with an electric shaver designed for animals. Studies were performed in vivo with exposures of 30 min per day at three different concentrations (100, 300, and 1000 ppm) of toluene and o-, m-, and p-xylene for a total of 10 times over 2 weeks. Newly grown hair was tweezed out from the root with tweezers at seventh of the last exposure. Hair samples were then washed, extracted, derivatized, and analyzed by gas chromatography-mass spectrometry (GC-MS). HA and o-, m-, and p-MHA were not detected (ND) in the unexposed rat hair. After exposure, the metabolite concentration in the hair changed depending on the exposure concentration. Mean concentrations ranged from ND to 7.6 ng/mg, from ND to 13.8 ng/mg, from ND to 10.1 ng/mg, and from ND to 9.2 ng/ml hair for HA, o-, m-, and p-MHA, respectively. These results indicate that the metabolites concentrations in hair are effective indices of thinner exposure.

Animals↗

PubMed2003

Headspace solid-phase micro-extraction and gas chromatography with micro-electron capture detection for the measurement of p,p'-DDE in rat whole blood and hair.

A sensitive, specific, and reproducible capillary gas chromatography (GC) with micro-electron capture detection (micro-ECD) method using headspace solid-phase micro-extraction (HS-SPME) for the quantitative analysis of p,p'-DDE in rat whole blood and hair was developed. A 100 microm polydimethylsiloxane (PDMS) phase was used for the extraction. The obtained detection limits were 0.003 ng/mg and 0.004 ng/mg in whole blood and hair, respectively, at a signal-to-noise ratio of 3 (S/N = 3). Linearity was obtained in the ranges 0.003-2.0 ng/mg and 0.004-2.0 ng/mg in whole blood and hair, respectively, and the correlation coefficients of whole blood and hair were greater than 0.998. This method was successfully applied to the analysis of p,p'-DDE in rat whole blood and rat hair after an oral dose of p,p'-DDE.

Animals↗

PubMed2002

Temporal changes in testis weight during the past 50 years in Japan.

The ever-increasing presence of environmental toxicants and their disruptive effect on the reproductive systems of wildlife raises the question of possible damage to the human reproductive system. Using medicolegal data from over 20,000 Japanese men subjected to necropsy from 1948 to 1998, we investigated temporal changes in testis weight to find possible evidence of male reproductive disorders. We also carried out a histological examination of 747 testes collected from 1978 to 1998. Our detailed analyses of the development of testis weight over the past 50 years have revealed four clear phenomena: (i) the age at which testis weight reaches its maximum has decreased; (ii) peak weight showed a general increase until it started to decline in boys born after 1960; (iii) the decline-rate at which testis weight decreases after its peak has greatly accelerated; and (iv) the onset of increasing testis weight of boys has occurred at a progressively younger age. Our quantitative analyses of testis weight indicate the possibility of a subtle reproductive disorder in Japanese men, especially in those born after 1960. Together with the accelerated development and decline in testis weight during the past 50 years, the decline in peak weight might be indicative of a subtle interference of environmental toxicants with male reproductive organogenesis.

Adolescent↗