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Short tandem repeat studies are powerful tools for parentage analysis and for identification of missing persons, victims of murder, and victims of mass fatalities when reference samples are unavailable. The primer in the Identifiler® kit failed to amplify an allele at the D19S433 locus, producing a silent (“null”) allele. The causal mutation is a base change (G>A) 32 nucleotides downstream from the 3′ end of the AAGG repeats. The silent alleles are problematical in parentage analysis because when transmitted, they can cause a parent–child inconsistency that is unrelated to Mendelian genetics. The inconsistency is sometimes termed an “apparent opposite homozygosity” and it produces false evidence of nonparentage. Alternative primers were designed to amplify the D19S433 locus alleles and they detect the silent allele. Frequencies of the (no longer) silent allele were determined to be 0.0114 in 176 people from Shizuoka (Honshu) and 0.0128 in 156 people from Okinawa.

A 22-year-old man was found dead after he had continued to sit on a reclining chair for 2 years. He had consumed an unbalanced diet, kept wearing the same pair of socks and never washed himself for the term. His skin of bilateral crura developed into elephantiasis with severely festered ulcers on its surface. At autopsy, subcutaneous edema was significant in his lower limbs, and chronic circulatory disturbance of lymphoducts and veins was observed histologically. There were no crucial findings to account for chronic edema in the lower limbs. It has been reported that maintaining a seated posture obstructs both lymphoducts and veins because of bending the groin, decreases their return flow by inducing muscular atrophy, and causes subcutaneous edema in the lower limbs. Oligotrophia and dirt on his limbs might have exacerbated the chronic edema in elephantiasis. We concluded that a long-term abnormal life-style had caused fatal elephantiasis.

When mitochondrial DNA (mtDNA) heteroplasmies are detected, they often confound forensic identification, especially if they are the result of poor biological sampling. In this study, we determined the ratio of heteroplasmy in samples that were amplified from a very small amount of template mtDNA or a few cells using a highly sensitive nested polymerase chain reaction (PCR) procedure and a direct sequencing analysis. As a result, more than half of the detected sequences (i.e., 17/20, 15/20, and 14/20) showed homoplasmy derived from a variation in the heteroplasmy proportion when only 10 copies of template mtDNA samples were amplified and analyzed. Additionally, with products amplified from one or several white blood cells (WBCs), several previously undetected heteroplasmies were detected. These results indicate the risks associated with using highly sensitive mtDNA techniques in forensic investigations because of the variable proportions of heteroplasmy or nucleotide substitutions that can possibly be detected from a very small biological sample.

Two autopsy cases, where the individuals were suspected of having ingested acephate, an organophosphorous insecticide, are reported. Acephate and its active metabolite, methamidophos (MP), were analyzed in the biological fluids by GC/MS, using the salting out method with liquid-liquid extraction columns. The first case was that of a 70-year-old man whose blood acephate was 149 microg/mL, and MP was 3.0 microg/mL. Serum pseudocholinesterase (ChE) activity was inhibited. No remarkable finding of injury or disease was determined as the cause of his death, but acute poisoning by acephate was mostly suspected. The second case was that of a 60-year-old man. A deep gash in the left neck injured the left common carotid artery in addition to the severely ischemic state of the primary organs. His blood acephate was 46 microg/mL, and MP was not detected. ChE activity was in the normal range. Hemorrhage was mainly suspected as the cause of his death. The concentrations of acephate and MP in human blood after oral ingestion are first reported here, and the acute toxic level of acephate is discussed.

A denaturing gradient gel electrophoresis (DGGE) assay was used to detect mitochondrial DNA (mtDNA) sequence heteroplasmy in 160 hairs from each of three individuals. The HV1 and HV2 heteroplasmic positions were then identified by sequencing. In several hairs, the heteroplasmic position was not evident by sequencing and dHPLC separation of the homoduplex/heteroduplex species was carried out with subsequent reamplification and sequencing to identify the site. The overall detection frequency of sequence heteroplasmy in these hairs was 5.8% (28/480) with DGGE and 4.4% (21/280) with sequencing. Sequence heteroplasmy of hair was observed even when the reference blood sample of the individual was homoplasmic. The heteroplasmic positions were not necessarily observed at sites where high rates of substitution have been reported. In two hairs, a complete single base change from the reference blood sample was observed with sequencing, while the heteroplasmic condition at that site in the hair was observed using DGGE. The DGGE results in such samples would serve as an aid in considering the possibility of match significance. In a forensic case, this situation would lead to the possibility of a failure to exclude rather than to be inconclusive.

Penta E in the PowerPlex 16 kit is a pentanucleotide tandem repeat marker located on Chromosome 15, containing an AAAGA repeat motif. Variant alleles (18.4 and 19.4) were found in the Japanese population. A sequence analysis revealed that both the variant alleles had a partial repeat motif of AAAA, resulting in one-base-shorter alleles compared to known alleles. Despite the relatively large amplicon sizes (379 to 474 bp) of Penta E, an accurate allele assignment can be reliably made by capillary electrophoresis. However, alleles differing in size by only one base (e.g., 18.4 and 19) were not separated and appeared as a single broad peak. The Genotyper software assigned one of the component alleles to this peak. Therefore, such broad peaks require careful interpretation so as to not overlook the other component allele contained by the peak. As an index to recognize a peak containing two alleles, the ratio of peak area to peak height was found to be useful.

In analyzing aged samples by the AmpliType PM PCR amplification and Typing kit, it was occasionally observed that color developed typing strips had dark allele dots on PM loci but no visible S dot. Since the S dot acts as a minimum dot intensity control to determine positive alleles on the PM loci, it is necessary to apply another control system. To achieve positive PM typing from a degraded DNA sample that is inferred to be derived from a single donor, a standard has been adopted wherein loci from which sufficient PCR products are observed on agarose gel can be typed. The objective determination of sufficient PCR was done by comparison between band peak height of each locus generated from a sample and that of the corresponding locus generated from two nanograms (recommended minimum quantity as template DNA) of the control DNA provided in the kit.

A victim who was presumed to have ingested waste fluid containing phenol of DNA extraction was found dead in his laboratory. The skin was partially chemically burned, with blisters as maps. No mechanical injuries were observed. The pathological findings of the liver and kidney were typical of those of acute substantial poisoning. Phenol concentrations in the blood, urine, stomach contents and organs were determined by gas chromatography/mass spectrometry. Phenol was distributed throughout the body. The concentration of free phenol in the blood was found to be 60 micrograms/mL, and in the urine it was 208 micrograms/mL. The phenol concentrations in the organs were found as follows: 106 micrograms/g in the brain; 116 micrograms/g in the lungs; 166 micrograms/g in the liver, and 874 micrograms/g in the kidney, respectively. Significantly high concentrations were observed in the kidney, urine, and liver. To the best of our knowledge, such an intoxication through this kind of ingestion has never been reported before. Distributions of phenol in fatal poisonings have been reported, but colorimetry was used as the analytical method and it cannot exclude the interference of other phenolic compounds.

A genetic locus (D1S58, defined by DNA probe pMCT118) that contains a variable number of tandem repeats (VNTR) has been successfully amplified from a very small amount of genomic deoxyribonucleic acid (DNA) by the polymerase chain reaction (PCR). The DNA sequence of the locus was determined and was found to consist of a 16-base consensus sequence and flanking sequences. Oligonucleotide primers complementary to the flanking sequences were synthesized to serve as primers for amplification of MCT118 by the PCR method. Human genomic DNA isolated from blood (2 ng from each sample) was successfully amplified at the MCT118 locus, and polymorphic bands were detectable by ethidium bromide staining after electrophoresis on polyacrylamide gels. Determination of genotypes at this VNTR locus can now be routinely achieved within 24 h, without the need for Southern blots or radioactive materials. Furthermore, the small size (387 to 723 base pairs) of the DNA fragments produced in the PCR amplification permits good resolution of individual alleles that differ by only one repeat unit. The precise specification of the number of tandem repeats present in each allelic fragment is reproducible from one analysis to another.