Enzyme-linked immunosorbent assay for determination of plasma thyroglobulin and its application to post-mortem diagnosis of mechanical asphyxia

A high sensitive enzyme-linked immunosorbent assay (ELISA) for determination of plasma thyroglobulin was devised and applied to the postmortem diagnosis of mechanical asphyxia. The sensitivity of the present ELISA was 5 ng/ml. All of the 15 victims who died from causes other than mechanical asphyxia showed plasma thyroglobulin levels lower than 200 ng/ml (99.8 +/- 37.9 ng/ml), while 12 out of 14 victims of mechanical asphyxia showed the levels higher than 200 ng/ml (2100 +/- 3450 ng/ml in 14 victims). Thus, the present ELISA appears to be useful for postmortem diagnosis of mechanical asphyxia.     

Storage of blood for methemoglobin determination: comparison of storage with a cryoprotectant at -30 degrees C and without any additions at -80 degrees C or -196 degrees C

Changes in methemoglobin (Met-Hb) concentrations during storage of whole blood or mixtures of blood and a cryoprotectant at refrigerated or various freezing temperatures were examined using blood samples from nitrite-administered rats and from autopsy cadavers. When whole blood was stored at 3 degrees C, Met-Hb reduction was observed in blood samples from nitrite-administered rats and in the blood from a victim poisoned by a weed killer containing some oxidant. When samples were stored at -30 degrees C, Met-Hb formation by autoxidation was inevitably observed in blood samples stored as whole blood, whereas addition of a cryoprotectant to whole blood could prevent Met-Hb formation in all the blood samples. When whole blood was stored at -80 degrees C or -196 degrees C, Met-Hb concentrations were practically stable until at least 30 days regardless of the initial values except in the control rat blood samples stored at -80 degrees C which showed slight formation of Met-Hb. From the results obtained, both the storage with a cryoprotectant at -30 degrees C and that without any additions at -80 degrees C or -196 degrees C proved to be suitable for long-term storage of blood samples from autopsy cadavers for Met-Hb determination.     

Deoxyribonucleic acid (DNA) typing of human leukocyte antigen (HLA)-DQA1 from single hairs in Japanese.

The deoxyribonucleic acid (DNA) typing of human leukocyte antigen (HLA)-DQA1 from single hairs is described. HLA-DQA1 genotypes could be determined from single plucked hair roots. However, it was not easy to type HLA-DQA1 with hair shaft portions. Increase in the specimens of hair shaft portions (over 10 cm in length) to get sufficient DNA caused inhibition of polymerase chain reaction (PCR). Synthetic melanin as well as the one extracted from hairs inhibited the PCR of the genomic DNA template when added to the PCR reaction at the concentrations over than 15 ng/100 microL. Therefore, typability of hair shaft portions seems to depend on the delicate balance of the concentrations of DNA and the contaminated melanin in the final DNA extracts.