A case of homicidal intoxication by chloropicrin

An 18-year-old girl and her boyfriend were sprayed with toxic chemicals from the left front door of their parked car. The girl died of intoxication about 4 h later. The main findings of postmortem examination were spotty discolorations on her skin and severe pulmonary edema. The unknown chemical was identified as chloropicrin by gas-liquid chromatography and gas chromatography-mass spectrometry of her lung and on samples from the car's console box, cassette tape case, and floor mat, all of which were wet with chemicals. The content of chloropicrin in her lung was calculated at 1.6 ng/g of wet weight.     

Sex identification of bloodstains by radioimmunoassay of sex hormones

A forensic application is reported for the sex determination of subjects whose dried bloodstains are analyzed by radioimmunoassay for testosterone and progesterone. Blood specimens of ten males and 15 females were collected, prepared as bloodstains, and then assayed at four-different time intervals for testosterone (T) and progesterone (P) contents up to 3 months later. The ratio of the two hormone contents ($\text{P}\text{T}$) was used to establish the sex origin of the dried blood specimens.     

A study on the combined action of CO and HCN in terms of concentration-time products

Acute toxicity at single and combined exposures of CO and HCN was studied on rats in terms of concentration-time product (ppm . min) necessary to kill animals (lethal CT). The animal was exposed individually to test gas in an animal chamber made of transparent plastics, and test gas was made in gas chamber connected to the animal chamber by a wide and short piece of plastic tube. HCN was produced by addition of NaCN solution to H2SO4 and in case of CO exposure, various amounts of pure CO were introduced. During exposure, gas samples were frequently taken. After exposure, blood sample was withdrawn from the right side of the heart. CO concentrations in the gas and blood were determined gas chromatographically. HCN in the gas sample was measured spectrophotometrically, after being absorbed into NaOH solution in a glass vessel devised by our laboratory. At single exposures, mean lethal CT for CO was 78,000 +/- 22,000 and for HCN was 4,700 +/- 940. In combined exposure, various combinations of CO and HCN were used. A fractional CT, defined as a ratio of CT to lethal CT, multiplied by 100, was calculated for each gas. A linear relationship between fractional CTs of HCN and CO was considered to show a simple additive action between the two gases. The sum of both fractional CTs averaged 100 +/- 26. On the other hand, linear relation was not observed between blood levels of the two toxicants at death.     

Puromycin-sensitive alanyl aminopeptidase from human liver cytosol: purification and characterization

A cytosolic alanyl aminopeptidase (AAP-S) was purified to homogeneity from human liver cytosol. The molecular weight of the purified enzyme was calculated to be approximately 98,000 on TOF-MS and 90,000 on SDS-PAGE in the presence of beta-ME. These findings suggest that the enzyme exists as a monomeric form in human liver cytosol. The enzyme rapidly hydrolyzed the substrates Ala-, Lys- and Phe-MCAs, and moderately hydrolyzed Met-, Leu-, Tyr- and Lys-Ala-MCAs at pH ranging from 7.5 to 8.0. The order of the K(cat)/K(m) values of AAP-S at the optimal pH was Arg->Arg-Arg->Met->Leu->Lys->Phe->Lys-Ala->Tyr->Ala-MCAs. It was strongly inhibited by bestatin, leuhistin, actinonin, amastatin, 1, 10-phenanthroline, DFP, PCMBS, Zn(2+), Cd(2+), Co(2+), Cu((2+)), Hg(2+) and puromycin. AAP-S was approximately 80 times more sensitive than human seminal plasma AAP (aminopeptidase N, membrane type). The amino acid sequence of the first 60 residues of AAP-S was highly homologous with the N-terminal amino acid sequence of the rat liver puromycin-sensitive enkephalin-degrading aminopeptidase. These physicochemical properties and findings indicate that AAP-S from human liver cytosol is identical to those of other puromycin-sensitive aminopeptidase(s). Furthermore, with immunohistochemistry the enzyme was strongly stained in the cytoplasm of liver cells and renal tubules, and was ubiquitously localized in various human tissues.     

Application of Postmortem 3D‐CT Facial Reconstruction for Personal Identification*

Abstract: Postmortem computed tomography (CT) images can show internal findings related to the cause of death, and it can be a useful method for forensic diagnosis. In this study, we scanned a ready‐made box by helical CT on 2‐mm slices in a mobile CT scanner and measured each side of the box to assess whether reconstructed images are useful for superimposition. The mean difference between the actual measurements and the measurements on the three‐dimensional (3D) reconstructed images (3D‐CT images) is 0.9 mm; we regarded it as having no effect on reconstruction for the superimposition method. Furthermore, we could get 3D‐CT images of the skull, which were consistent with the actual skull, indicating that CT images can be applied to superimposition for identification. This study suggested that postmortem CT images can be applied as superimpositions for unidentified cases, and thinner slices or cone beam CT can be a more precise tool.     

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.     

A novel fluorescent quadruplex STR typing system and the allele frequency distributions in a Thai population

We have previously reported a new triplex amplification and typing system by silver staining for three short tandem repeat (STR) loci, 9q2h2 (D2S3020), D15S233, and D14S299 without "microvariant" alleles such as .1, .2, and, .3 alleles in the Japanese population. In the present study, we established a new quadruplex system with an additional locus D7S809 using primer sets labeled with fluorescent multi-color dyes. Using this system, we genotyped 183 Thai people, found only one "microvariant" allele (allele 20.2) at D7S809, and calculated allele frequencies and some statistical properties at these four STR loci. From these allele frequencies at four STR loci, we performed three statistical analyses including a homozygosity test, a likelihood ratio test, and an exact test for Hardy-Weinberg equilibrium (HWE). Deviations from HWE (p < 0.05) were observed only in the two tests at the locus D7S809. In the present study, we compared the allele frequencies at these four loci in the Thai population to those in the Japanese population described previously. Consequently, all observed heterozygosities and power of discrimination (PD) at those loci in the Thai population were higher than 0.8 and 0.9, respectively, and all statistical values for discriminating power in the Thai population were slightly higher than those in the Japanese population. The combined paternity exclusion rate (combined PE) in the Thai population (0.978) was almost the same as that in the Japanese population (0.971). Therefore, this novel PCR amplification and typing system for four STR loci would be a convenient and informative DNA profiling system in the forensic field.     

Analysis of a soldered wire burnt in a fire

Fire investigators frequently encounter electrical wires with melted ends at fire scenes, which can provide useful information on the cause and development of the fire even when the melted ends result from the fires. A bead on a melted end of a wire was found in the area of origin of a massive fire that lasted for nearly a whole day, devastating a factory. The bead appeared to be the end of a wire soldered to a terminal. X-ray analysis showed that the bead is a tin-copper alloy. Although regular tin-lead solder was used in the factory, lead was not detected. This contradictory result stood in the way of fire investigation. Therefore, an unused wire soldered with tin-lead solder was heated in an electric furnace at 500 degrees C for 3 h for further examination. X-ray analysis of this wire showed that copper can be alloyed with tin while losing lead in a long-term heat in a fire.