Motohiko Yamazaki

Simultaneous detection of multiple STR loci on sex chromosomes for forensic testing of sex and identity

The forensic usefulness of X and Y chromosomal STR loci has recently been demonstrated. One quadruplex-PCR, using 2 X- and 2 Y-STRs (STRX1/HPRTB and DYS390/ DYS393), and 2 duplex-PCRs, each using an X- and a Y-STR (ARA/DYS390 and ARA/DYS393), and detection of PCR products by using an automated DNA sequencer are reported herein. This approach allows us to determine not only the sex of the donor of a sample, but also the X- and/or Y-STR genotypes of the sample. A male biological specimen yields 4 amplified products in quadruplex-PCR and 2 amplified fragments in duplex-PCRs, whereas a female biological specimen yields only 2 amplified fragments of X-STR in quadruplex-PCR and one fragment, also of X-STR, in duplex-PCRs. Our study thus provides useful information for many activities in forensic practice, such as identity testing, paternity testing, especially of deficiency cases, compilation of population data, and sex determination of a biological sample from a single PCR.

Rapid and clear detection of ABO genotypes by simultaneous PCR-RFLP method.

We reported a new approach of ABO genotyping by a polymerase chain reaction and restriction fragment length polymorphism method. Instead of amplifying the loci containing the positions of nucleotides 258 and 700 of cDNA of the A transferase separately, we successfully amplified these 2 loci together in one reaction mixture using 2 sets of primers. The amplified DNA products were digested at the same time with restriction enzymes Kpn I and Alu I. The digested DNA products were then separated by electrophoresis on polyacrylamide gel. In addition, we evaluated the influence of various amplification parameters (concentration of template DNA, primers, Taq DNA polymerase, MgCl2, and number of cycles). In particular, high Mg2+ concentration (3.5 mM) made effective amplification of this locus without producing any unspecific band. By using that optimized condition for PCR, together with a simultaneous approach, our study proved to be time saving, more economic, and convenient in interpreting the results.

Postmortem changes in drug-metabolizing enzymes of rat liver microsome

Postmortem changes in the drug-metabolizing enzymes in rat liver microsome were studied. Parameters investigated were: microsomal protein, NADPH-cytochrome P-450 reductase activity, NADH-cytochrome b5 reductase activity, cytochrome b5 content, cytochrome P-450 content, aminopyrine N-demethylase activity, aniline p-hydroxylase activity, p-nitroanisole O-demethylase activity, uridine diphosphate (UDP)-glucuronyl transferase activity and glutathione S-transferase activity. Nearly all the parameters based on microsomal protein decreased during autolysis and the time-dependent decrement ratios of the parameters changed by various amounts. Cytochrome b5 content decreased more rapidly than that of other components. By 36 h post mortem, levels of cytochrome b5 were not detectable. By 48 h post mortem, NADPH-cytochrome P-450 reductase activity decreased to 91%, NADH-cytochrome b5 reductase activity decreased to 94%, and cytochrome P-450 content decreased to 92% of relative activities. By 48 h post mortem, aminopyrine N-demethylase activity decreased to 87%, aniline p-hydroxylase activity decreased to 98% and p-nitroanisole O-demethylase activity decreased to 75% of relative activities. The activity of p-nitroanisole O-demethylase appeared to be more stable than that of aminopyrine N-demethylase or aniline p-hydroxylase. These results demonstrate that there are multiple forms of isozymes of the cytochrome P-450-linked monooxygenase system. Hepatic transferases showed decrease patterns different to those of monooxygenases, so UDP-glucuronyl transferase activity of approximately 32% of relative activity was detected at 48 h post mortem. Thus, UDP-glucuronyl transferase activity appeared to be more stable than the cytochrome P-450-linked monooxygenases. These results show that these activities and components would be useful as markers of postmortem time. The causes of the variety of instability of these enzyme systems are discussed.

An autopsy case of salt poisoning from drinking a large quantity of shoyu (Japanese soy sauce).

We report herein a suicide case of salt poisoning from drinking a large quantity of shoyu (Japanese soy sauce). The deceased was a 60-year-old housewife who was found dead in her bedroom by her husband. An empty 1,000 ml bottle of shoyu, which had been purchased on the day before death, was discovered in the kitchen. Macroscopically, the alimentary tract contained a yellowish-brown liquid-like material with the strong smell of shoyu, and slight lung and brain edema were noted. The 1,000 ml bottle of shoyu contained approximately 160 g of salt. Therefore, the cause of death was determined to have been salt poisoning from drinking a large quantity of shoyu.

An electrocution death of an infant who had received an electric shock from an uncovered oval shaped lamp switch in his mouth while in a hospital

A male infant aged one year and nine months was found dead on a bed after admission to hospital with suspected pneumonia. The patient apparently put an uncovered oval shaped lamp switch (pendant switch) into his mouth and died of electric shock after contacting the exposed wires of the switch (100 V, 60 Hz alternating current). There were extensive first- to fourth-degree burns on the inner surface of the both lips. Because the histological findings were consistent with electric burns and the burns showed vital reactions, electric shock was judged to be the cause of death. The pendant switch is normally a very convenient piece of bedside equipment for inpatients. However, when the patient is an infant who naturally puts all the objects into the mouth, such a switch should be placed out of reach, and it should be certain that the cap is not loose.

Detection of D1S80 (pMCT118) locus polymorphism using semi-nested polymerase chain reaction in skeletal remains

We evaluated the usefulness of a semi-nested polymerase chain reaction (PCR) method for detecting D1S80 (pMCT118) locus polymorphisms of DNA extracted from old skeletal remains. The semi-nested PCR has been applied to the amplification of D1S80 nucleic acid sequences. For amplification of the locus D1S80, a pair of oligonucleotide primers have been used widely as described by Kasai et al. We have designed another set of primers for semi-nested PCR. This method resulted in D1S80-VNTR detection from low-titered DNA isolated from old skeletal remains. The first and second step PCR achieved amplification from as little as 10 ng and 10 pg of template DNA, respectively. Specificity and sensitivity of the amplification products was markedly improved by semi-nested PCR. In DNA extracted from biological samples, this method took about 5 hours to amplify the target DNA and 3 hours for electrophoretic separation. We demonstrated that this semi-nested PCR method was superior in sensitivity to conventional 1-step standard amplification for VNTR typing of the D1S80 locus.

An unusual autopsy case of a victim stabbed during sadomasochistic prostitution

A 29-year-old male who lived alone was found dead with his back leaning against the wall of his room. He had been stabbed in his abdomen with a survival-type knife. The victims mouth was plugged with a pink-colored glove and was sealed with packing tape. His wrists were tightly tied behind his back with the same type of packing tape. The cause of death was diagnosed as hemorrhage from the right common iliac artery and vein. Due to the strange circumstances of the crime scene, the police initially considered the possibility of homicide by a group of assassins. Two months later, the police arrested a male suspect who was a member of a vice racketeer. The victim was characterized as a masochist and bisexual. He often hired the male suspect to perform sadomasochistic activities. On the day of the crime, the victim prepared a survival-type knife and packing tape himself to experience fear and pain more strongly. The victim hoped to use the knife to increase sexual excitement. In this case of sadomasochistic prostitution leading to death, the legal issues of homicide for money, malicious request of injury by the victim and accidental death were involved.

Detection of Sequence Variants in Hypervariable Segments of Mitochondrial DNA in the Asian Population

The analysis of highly polymorphic regions of mitochondrial DNA is one of the most commonly used methods for personal identification. The recent advances of fluorescent detection in automated DNA sequencing (Smith et al. 1986) has made it possible a rapid analysis of sequence variants without using isotopic labeling.

Amplification and detection of the VNTR locus D4S95 in a Japanese population

The D4S95-VNTR locus was amplified and the polymorphism analysed in a population sample of 169 randomly selected Japanese individuals. A total of 14 alleles containing 850–1360 base pairs were distinguished by agarose gel electrophoresis. The distribution of alleles was symmetrical with respect to one peak at 1030 bp. The mean exclusion chance and discrimination power were calculated as 0.604 and 0.876 respectively.