Nihon hoigaku zasshi = The Japanese journal of legal medicine最新文献

Since the introduction of DNA polymorphism analysis techniques to forensic science, forensic identification research has made radical, astonishing progress at a rate that has already rendered the initial methodologies introduced fifteen years ago obsolete. DNA extraction now can be quickly and efficiently performed by various kinds of commercially available kits. The advent of PCR has enabled the use of relatively crude and minute DNA as amplification templates while many kinds of new detection methods for analyzing the amplified products have also been developed. Although many minisatellites such as MCT118, YNZ22, COL2A1, and ApoB were highlighted at the beginning of 1980s, none of these loci, with the exception of MCT118, have proved useful for forensic DNA application due to their low amplification efficiency. On the other hand, STR loci containing four base pair repeat sequences have been used routinely for human identification since the mid-1990s. In the near future, the highly efficient STR should be selected as a consensus core marker in Japan. STR systems located on the Y chromosome are widely used in forensic science for the identification of male individuals. These systems have a special significance in forensic science cases where mixtures of male and female DNA are analyzed, as happens in cases of rape or other sexual crimes. The characteristics of high copy number, maternal inheritance, and high degree of sequence variability make mtDNA a powerful tool for forensic identification. Most of the variations in mtDNA among individuals are found within the displacement loop (D-loop). In all population groups, mtDNA sequences can be useful for discriminating among unrelated individuals. Now it is necessary to get as much as possible individual genetic information as quickly as possible in order to enable individual identification. We will create a new era in which forensic identification can be performed using microarray technology.

We report a rare case of sudden death of a patient with acute pulmonary thromboembolism associated with chlorine gas poisoning. A 21-year-old man in a water-filtration plant accidentally inhaled highly concentrated chlorine gas. He was immediately brought to a hospital after exposure. On admission, the patient had clouding of consciousness, dyspnea, and deep cyanosis. Arterial blood gas values indicated severe hypoxemia; PaO2 was 35.9 mmHg and PaCO2 was 42.4 mmHg. The clinical course was uneventful and he was satisfactorily recovering. However, ten days after admission he became sick and markedly cyanotic. He lost consciousness and then he went into cardiopulmonary arrest. Despite efforts at resuscitation, he died. An autopsy revealed bilateral pulmonary thromboembolism, although he apparently did not have any risk factor for embolism. The toxicity of chlorine gas may be related to the pulmonary thromboembolism, but the mechanisms leading to his death are unclear.

We report the autopsy case of a 41-year old passenger who suffered a significant head injury with a typical ring fracture at the base of the skull as a result of a violent fall from a bicycle. Several reports about ring fractures of the base of the skull revealed that they were due to crashing a car at high speed, a collision and/or a fall while riding a motorcycle and a fall in piloting a gyrocopter and so on resulting in severe injury to another part of the body. In this case, the ring fracture occurred when his spine was pushed up by high impact of the parieto-occipital region against the ground.

With a limited budget, it is difficult for our department to have a well-equipped toxicological laboratory with sufficient members of trained personnel. Alcohol levels in the body fluids and carbon monoxide levels in the blood are routinely measured using gas chromatography and UV spectrophotometer, respectively. Some drugs can be detected by the drug screening test on the market, such as Triage test. When poisoning is certain in a criminal case, I entrust another forensic laboratory with analyzing. In some non-criminal cases, a clinical laboratory of a private company may be chosen. In other cases, however, the samples are only kept in a freezer. In case of outside order, a guideline to provide an adequate chain of custody will be necessary.

We have previously examined several ABO blood grouping antibodies with whole saliva and observed that there were two types of antibodies. One group of antibodies reacted with both secretory and non-secretory saliva, and the other with only secretory saliva. In order to clarify the differences in reaction of the antibodies with saliva, we needed to analyze of antigens in secretory and non-secretory saliva. Therefore, we prepared blood group active glycoproteins from secretory and non-secretory saliva by affinity chromatography and gel filtration. The secretory saliva gave three active peaks, one large peak in the void volume and two small peaks in fractions of smaller molecular weights on Sepharose-CL6B after the affinity chromatography. From the non-secretory saliva, a single active peak in the void volume, which corresponded to the major peak in the secretory saliva, was found. Most blood group activities were found in those void volume fractions. Moreover, capillary electrophoresis showed that these blood group active glycoproteins were identical, and that there were immunological differences between secretory and non-secretory salivary blood group substances.

Constant Denaturing Gel Electrophoresis (CDGE) was used as an analytical method of the genetic markers. Even a single base change in a fragment amplified by PCR was detected exactly by CDGE. The computational simulation of CDGE gave the calculation whether a single base change in a fragment amplified by PCR could be detected by CDGE or not. In this report, genotyping of three blood groups, MN, Duffy and Kidd, and Gc system is described. The regions reflecting allelic differences of each system were amplified from genomic DNAs. The concentration of denaturants (urea and formamide) in CDGE gels was decided with the computational simulation as follows: 15% for MN, 27% for Duffy, 24% for Kidd, 30% for Gc. CDGE was run in TBE buffer at 60 degrees C, 100 V constant voltage. PCR amplified fragments with 1-3 base changes were separated clearly in each gel. By staining the gels with ethidium bromide, the genotype of each system was determined. The genotyping of system by CDGE can avoid mistakes in the conventional method, which requires complicated and multiple troublesome operations. Analysis of PCR amplified fragments by CDGE will make a beneficial contribution to medico-legal practice.

An improved procedure for ABO blood typing by the absorption-elution test using commercially available monoclonal antibodies was established. The optimized elution temperature for anti-A monoclonal antibodies to be liberated from bloodstains was 54 degrees C and the temperature to deactivate the liberated antibodies was over 56 degrees C. The test condition was established using a monoclonal antibody manufactured by Biotest. For the anti-A monoclonal antibody the most effective elution time was 5 min and the long incubation time decreased the activity of the liberated antibodies. On the other hand, the conditions formerly used for absorption-elution tests were suitable for anti-B monoclonal antibody. A Type-A test and a Type-B test have to be performed separately for ABO blood grouping from forensic samples. The conditions established in this report were applied to the absorption-elution test to achieve an improved result for ABO blood grouping from hair samples.

Generally, the drugs are analyzed by the forensic medicine department in the most of autopsy cases. The forensic medicine department cannot always perform toxicological analysis because a shortage of a verified personnel, appropriate instruments, and financial resources. In order to overcome these difficulties and lack of resources, we developed a computer network called ml-poison. This network consists of the staff of forensic medicine, hospitals, governmental agencies and research facilities of police departments, etc. This network offers immediate and valuable information and expertise to these inexperienced in dealing with cases of poisoning. In cases in which the toxicological analysis cannot be performed in a facility, the network will recommend a facility where the analysis can be performed. Up this point, the network order system has assisted in many cases of poisoning. Although the effectiveness of the network for toxicological analysis has been proven, we still must deal with severed difficult problems: 1. The number of facilities assisting network orders is limited. 2. Who will pay the expenses involved in the analysis. 3. How to maintain security of the system. 4. What agency will assume responsibility for the management of the system.