Naomi Nakamaru

Prediction of response to 5'-deoxy-5-fluorouridine (5'-DFUR) in patients with inoperable advanced gastric cancer by immunostaining of thymidine phosphorylase/platelet-derived endothelial cell growth factor.

Background: No reliable method is available for predicting the response to chemotherapy in patients with gastric cancer. The anticancer drug 5′-deoxy-5-fluorouridine (5′-DFUR) is converted into 5-fluorouracil (5-FU) by thymidine phosphorylase (dThdPase). We studied the relation between the expression of dThdPase in tumor tissue and the response to treatment with 5′-DFUR to determine if this enzyme can be used to predict the response to chemotherapy. Methods and Materials: We performed endoscopic biopsy and studied the expression of dThdPase by immunostaining with anti-dThdPase monoclonal antibody in 41 patients with inoperable advanced gastric carcinomas before they received multiple-drug chemotherapy, including 5′-DFUR. The relation between the expression of dThdPase and the response to chemotherapy was studied. We also studied the characteristics of positive cells against anti-dThdPase monoclonal antibody. Results: The response rate among patients whose tumors were positive for dThdPase expression (56.8%, 21/37) was higher than that among patients whose tumors were negative for dThdPase expression (0%, 0/4; p = 0.048). Spindle-shaped cells darkly expressing dThdPase were sporadically seen surrounding cancer nests in some patients. Multiple-antibody immunostaining suggested that these spindle-shaped cells were perivascular mesenchymal cells. The response rate was 82.4% (14/17) among patients with spindle-shaped cells strongly positive for dThdPase, as compared with 29.2% (7/24) among those with spindle-shaped cells weakly positive or negative for dThdPase (p = 0.00131). The expression of spindle-shaped cells darkly stained with dThdPase was the factor most strongly related to the response to chemotherapy (odds ratio = 35.513, p = 0.0027). Conclusions: The expression of dThdPase in stromal spindle-shaped cells may be a useful index in predicting the response to 5′-DFUR in patients with gastric cancer.

Analysis of the sarcomere protein gene mutation on cardiomyopathy - Mutations in the cardiac troponin I gene

Developments in the molecular genetic studies of cardiomyopathy (CM) have led to discovery of a large number of mutations in the genes encoding the sarcomeric proteins. In this study, comprehensive screening of TNNI3 was performed in 36 consented autopsy cases diagnosed as CM, in order to evaluate the prevalence of gene mutations in sudden death caused by CM. In DCM cases, a new missense mutation Pro16Thr was detected. A single nucleotide polymorphism at -8 position of intron 3 (IVS 3 -8 T>A) was identified, which had a significant difference in allele frequency between DCM and control cases. From these results, it was indicated that this study contribute to genetic based diagnosis, risk stratification and prevention of sudden death caused by CM.

ABO genotyping by TaqMan assay and allele frequencies in a Japanese population

ABO genotyping have become common tools for forensic casework. We developed a new rapid ABO genotyping method using a fast real-time PCR system with the TaqMan® Sample-to-SNP™ Kit. Eight single nucleotide polymorphism (SNP) sites in the ABO gene (nt 261, 297, 467, 657, 703, 829, 930 and 1061) were selected to determine the ABO genotypes. ABO genotypes were easily determined by examining allelic discrimination patterns. This method enabled analyses to be completed in about 1h per plate with no postmortem change influences. The detection limit in each SNP site was examined as 100pg per reaction. ABO genotyping from 1000 Japanese individuals was also examined to determine the distribution of ABO genotypes and allele frequencies. Thus, 31 genotypes were clearly identified, and these were controlled by four common and seven rare alleles. The power of discrimination, heterozygosity and polymorphism information contents were 0.913, 0.775 and 0.812, respectively. Therefore, selecting these eight SNP sites could be useful for high specific ABO genotyping. This rapid, sensitive and accurate genotyping method is useful for forensic casework.

Simultaneous determination of 5 psychotropic drugs of various types in an autopsy case of acute multiple drug poisoning.

We attempted the simultaneous determination of 5 drugs, mirtazapine, sertraline, chlorpromazine, amoxapine and zolpidem, detected in a gas chromatography-mass spectrometry screening test in an autopsy case. The solid-phase extraction of the analytes from biological samples was achieved using Oasis(®)HLB cartridges (Waters, Milford, MA, USA). Gas chromatography was performed on a HP-5MS fused silica capillary column (30 m × 0.25 mm i.d., 0.25 μm film thickness, Agilent Technologies). The mass spectrometer was operated with an electron energy of 70 eV in electron impact mode. The qualitative and quantitative analyses were performed in full-scan mode and the selected ion monitoring mode, respectively. The total ion chromatogram showed good separation of these drugs. Linear graphs were obtained with good correlation coefficients for these drugs from 0.001 to 2.0 μg/mL (r(2)=0.9909-0.9986) using imipramine-d6 as an internal standard. The recoveries of these drugs were found to be 62.8-88.0% in spiked whole blood. Mirtazapine, sertraline, chlorpromazine, amoxapine and zolpidem were found in post-mortem samples of the deceased at concentrations of 2.67, 0.07, 0.25, 0.32 and 0.68 μg/mL, respectively. The concentration of mirtazapine was within the lethal level and those of amoxapine and zolpidem were within the toxic level. We diagnosed that the cause of death was acute multiple drug poisoning. The simple and practical procedure used in this study is useful for the simultaneous determination of psychotropic drugs of various types in post-mortem biological samples.

A case of V-A shunt catheters migration into the pulmonary artery

A man in his sixties, who developed CPA at home, was transferred to the emergency center. Since CT images revealed a tube-shaped foreign body in the pulmonary artery, pulmonary embolism was initially suspected; however, this did not lead to a definite diagnosis. Autopsy revealed that the foreign body in the cadaver was a fragment of a V-A shunt catheter implanted about 30 years previously for the treatment of hydrocephalus. Although fibrous adhesion of a part of the catheter to the pulmonary artery wall was seen, suggesting that a fracture of the catheter had occurred a long time before, it was not known when the fracture had occurred. Since no pulmonary arterial obstruction secondary to the catheter or new thrombi, which had been initially suspected, were observed, the cause of death was determined to be ischemic cardiac failure. A fracture of a shunt catheter may be typically associated with some clinical manifestations, which are often found and treated. In this case, however, no symptoms appeared and the fracture of the shunt catheter remained untreated for a long time. This case was therefore considered to be extremely rare, and is an example of how a serious iatrogenic disease could occur.

A fatality due to inhalation of 1,1-difluoroethane (HFC-152a) with a peculiar device

A man aged in his thirties was found dead in his room, wearing a gas mask connected with two plastic bags. An empty canister of Air Duster was in one of the plastic bags. Toxicological analysis by gas chromatography (GC)-mass spectrometry and GC-flame ionization detection revealed the presence of 1,1-difluoroethane (HFC-152a), which is a component of the Air Duster aerosol. Quantitative analysis showed that the concentration of 1,1-difluoroethane in his heart blood was as high as 546 μg/ml. The cause of death was diagnosed as acute poisoning by 1,1-difluoroethane. It was supposed that he abused the Air Duster product to obtain euphoria and inhaled 1,1-difluoroethane at excessive concentrations with the peculiar tight-fitting gas inhalation device, resulting in his death.