Comparison of Age Estimation in Japanese and Scandinavian Teeth Using Amino Acid Racemization*

Abstract: Racemization method is currently considered to be one of the most accurate methods for age estimation. There are many factors that affect racemization reaction velocities. We investigated ethnic differences in the racemization reaction velocities between Japanese and Scandinavian teeth. After a heating experiment, the Arrhenius equation was used to obtain a rate constant (k). Both groups presented almost identical velocities, indicating that there was no difference in the tooth racemization reaction between the two groups. However, because 14 of the 18 Scandinavian teeth had multiple roots, it is possible that accurate racemization rates of the teeth themselves were not reflected in the results. These findings reconfirm that the type of tooth selected is extremely important when evaluating age by racemization.     

Discrimination of paper-based kraft tapes using Fourier transform of transmitted light images

This study focused on two-dimensional fast Fourier transform (2D-FFT) as a new technique for the discrimination of kraft tapes, which is a kind of adhesive packing tape. The 2D power spectrum (2D-PS) obtained by applying 2D-FFT to an image enables us to obtain information about the spatial periodicity, even if the periodicity is invisible within the image. However, in the case of kraft tape, peaks in the 2D-PS are too unclear to determine its periodicity. We developed novel analytical image processes combined with 2D-FFT. 2D-FFT was applied to 50 randomly selected areas in a transmitted light image of kraft tape. The 2D-PSs were calculated from each area without applying a logarithmic transformation, accumulated, and processed by the removal of the area surrounding the center, and finally normalized for visualization. These processes enhanced the peaks and eliminated local variations. Through an intra-roll comparison, the 2D-PSs collected from a roll were similar in the location of the peaks and in their patterns at low frequency area. Using an inter-roll comparison, the 2D-PSs from 50 commercially available brand-name products were classified into 26 groups based on these peaks and patterns. All results demonstrate that this method, which is convenient, rapid, and non-destructive, could be a valuable tool for the identification of kraft tapes.     

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.