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Biomedical subjects

M Iwasa

Publications and source records attributed to M Iwasa.

At least 37 records · Page 2Linked to original sources
PubMed2000

Methamphetamine induces an increase in cell size and reorganization of myofibrils in cultured adult rat cardiomyocytes.

To investigate the direct effects of methamphetamine (MAP) on cardiac lesions seen in MAP abusers, isolated adult rat ventricular cardiomyocytes (ARCs) were exposed to MAP (0.05-1.0 mM) in medium 199 containing 10% fetal calf serum. Isolated ARCs attached to laminin-coated substrata and began to spread into polygonal shapes with pseudopodia at day 6 in normal culture. However, the cell attachment and spreading were inhibited by exposure to MAP (0.5 and 1.0 mM) for the first 7 days in culture. On the other hand, exposure to MAP (0.05 and 0.1 mM) for 7 days after a 6-day period of normal culture, led to a larger cross surface area of cells with more abundant actin bundles compared to control cells (p < 0.05). This development of spreading area resembled that of norepinephrine-treated ARCs. In addition, immunoreactive atrial natriuretic peptide (ANP) granules developed and accumulated around the nuclear region of ARCs exposed to MAP and the number of ANP positive cells tended to increase in a dose-dependent manner. These results suggest that chronic exposure to a high concentration of MAP may directly inhibit development of ARCs in culture and that a continuous exposure to a low concentration of MAP may facilitate the development of cellular hypertrophy. Therefore, hypertrophied cardiomyocytes in MAP abusers may be provoked by multifactorial incidents of direct and indirect actions of MAP.

Animals↗
PubMed2000

Catheter interventional treatment in Kawasaki disease: A report from the Japanese Pediatric Interventional Cardiology Investigation group.

OBJECTIVE: To assess the current status of catheter intervention in Kawasaki disease and to evaluate its efficacy and outcome. STUDY DESIGN: A questionnaire was sent to 55 major institutions in Japan. RESULTS: A total of 58 procedures in 57 patients were reported. The median age at the time of intervention was 12.1 years. The procedures included percutaneous transluminal coronary angioplasty (PTCA; n = 34), percutaneous transluminal coronary rotational ablation (PTCRA; n = 13), directional coronary atherectomy (DCA; n = 4), and stent implantation (n = 7). The immediate success rate was 74% for PTCA, 100% for PTCRA, 100% for DCA, and 86% for stents. The interval from the onset of disease to intervention in successful PTCA (n = 25) was significantly shorter than that in unsuccessful PTCA (n = 9). Restenosis after PTCA was observed in 24%. Development of new coronary aneurysms was reported in 3 patients for PTCA, 2 for PTCRA, 3 for DCA, and 1 for stents. Except for the DCA, all new aneurysms were associated with the use of high-pressure balloon inflation. Two deaths were reported as acute complications. CONCLUSIONS: Catheter intervention is a promising therapeutic strategy in the management of coronary stenosis caused by Kawasaki disease. Care should be paid to avoid acute coronary arterial complications and the development of new coronary aneurysms.

Adolescent↗
PubMed2000

Decrease of regional cerebral blood flow in liver cirrhosis.

OBJECTIVE: Alterations of regional cerebral blood flow (rCBF) in subjects with liver cirrhosis have not been fully evaluated. We evaluated quantitative changes in rCBF using single photon emission computed tomography (SPECT). METHODS: Twenty-eight Japanese patients with liver cirrhosis were enrolled in this study. None of them exhibited advanced hepatic encephalopathy at the time of examination. The cause of liver cirrhosis was viral infection in 26 patients; the cause was unknown in two patients. Child-Pugh classification of the patients was as follows: Group A, 12 patients; Group B, 12 patients; and Group C, four patients. The control group consisted of 25 age-matched healthy subjects. Radionuclide angiography was performed by rapid injection of Tc-99m ethyl cysteinate dimer (ECD) (740 MBq) via the right cubital vein, and then SPECT brain images were taken. Using the Patlak graphical method, rCBF values (ml/100 g per min) were calculated in the frontal, parietal, temporal and occipital lobes and cerebellum on SPECT images. RESULTS: The rCBF values were lower in cirrhotic patients than in controls, i.e. by 15% in the frontal lobe, by 12% in the parietal lobe, by 10% in the temporal and occipital lobes, and by 7% in the cerebellum. They decreased concomitantly with the severity of liver disease. A significant negative correlation was noted between rCBF values and Child-Pugh score in the frontal (P<0.01), parietal (P<0.05) and occipital lobes (P<0.01). rCBF values of each region were not correlated with age or with results of neuropsychological test. The degree of association between rCBF values and results of laboratory examination was generally poor. CONCLUSION: Patients with liver cirrhosis without advanced encephalopathy showed widespread reduction in rCBF; this reduction was particularly evident in the frontal lobe. Tc-99m ECD SPECT may be useful for evaluating cerebral functional changes in patients with liver cirrhosis.

Brain↗
PubMed2000

Effect of administration of nucleosides and nucleotides on protein turnover and the hypoxic myocardium.

Nucleotides and nucleosides have effects on improving energy metabolism and enhancing immune function. Under a surgical stress, requirement of nucleotides are increased as well as nitrogen. A well-balanced nucleoside solution (OG-VI) was developed for parenteral administration and its effect was examined in animals. The OG-VI solution contained 3.11% of nucleosides which was composed of inosine, guanosine monophosphate, cytidine, uridine and thymidine of 4:4:4:3:1 in molar ratio. The whole body protein turnover increased significantly in rats received total parenteral nutrition (TPN) with OG-VI after 70% hepatectomy and enhanced the fractional protein synthesis rates of the muscle and liver. Also myocardial contractility (%segment shortening, %SS) in dogs after occlusion of left anterior descending artery (LAD) was recovered to 70% after reperfusion in the OG-VI group. The creatine phosphate (PCr) / inorganic phosphate (Pi) was maintained the baseline level and did not decrease after hypoxia in the OG-VI group while PCr/ Pi was decreased after hypoxia in normal rat. These data suggested that the nucleoside-nucleotide (OG-VI) improved nitrogen metabolism and might stimulate synthesis of high-energy phosphate in recovery after severe surgical stress.

Animals↗
PubMed1999

High prevalence of transfusion-transmitted virus among patients with non-B, non-C hepatocellular carcinoma.

BACKGROUND: Many patients with hepatocellular carcinoma are positive for hepatitis B surface antigen (HBsAg) or antibodies to hepatitis C virus (anti-HCV). Recently, transfusion-transmitted virus (TTV) DNA was identified in the serum of patients with non-B, non-C posttransfusion hepatitis. In this study, the prevalence of TTV DNA in the serum of patients with non-B, non-C hepatitis-associated hepatocellular carcinoma was evaluated. METHODS: Fifteen patients with hepatocellular carcinoma negative for HBsAg, antibodies to hepatitis B core antigen (anti-HBc), and anti-HCV antibodies were enrolled in this study (non-B, non-C group). Fifteen patients positive for HBsAg and negative for anti-HCV antibody (HBV group) and another group of patients negative for HBsAg but positive for anti-HCV antibody (HCV group) were also enrolled in this study. Data obtained from 27 healthy subjects negative for both HBsAg and anti-HCV antibody and normal levels of serum alanine aminotransferase represented controls. The healthy control group, the non-B, non-C group, and the HCV group were age-matched. TTV DNA was detected by heminested polymerase chain reaction in which specific primers were used. RESULTS: TTV DNA was detected in 10 of 15 patients (67%) in the non-B, non-C group. This prevalence rate in the non-B, non-C group was significantly higher than that in the HBV group (3 of 15 patients, 20%) and the control group (9 of 27 patients, 33%), but it was not significantly different from that in the HCV group (7 of 15 patients, 47%). The noncancerous hepatic tissue samples of 10 TTV-DNA positive patients in the non-B, non-C group included 2 with chronic hepatitis and 8 with cirrhosis. CONCLUSIONS: This study showed that TTV DNA is frequently detected in the serum of patients with non-B, non-C hepatocellular carcinoma. This result suggests a potential pathogenetic association between hepatocellular carcinoma and TTV infection.

Aged↗
PubMed1999

Detection of Escherichia coli O157:H7 from Musca domestica (Diptera: Muscidae) at a cattle farm in Japan.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 was isolated for the first time from Musca domestica L. A total of 310 fly samples was collected from 4 different farms in Obihiro-City, Hokkaido, in the summer and autumn of 1997;5 samples carried E. coli serotype O157:H7. Using ELISA and Vero cell cytotoxicity assay, 3 isolates from 1 cattle farm produced both active Shiga-toxin type 1 (Stx1) and 2 (Stx2). These isolates also carried hemolysin and eaeA genes and harbored the 90-kb virulence plasmid of EHEC O157:H7. Based on plasmid profiles, antibiotic patterns, polymerase chain reaction (PCR)-based DNA finger printing analysis using random amplified polymorphic DNA, pulsed field gel electrophoresis analysis, and DNA sequences of stx1 and stx2, all 3 isolates from fly samples were identical. These results indicate that the house fly is capable of carrying the toxigenic EHEC O157:H7 involved in human disease.

Animals↗
PubMed1999

Magnetization transfer contrast of various regions of the brain in liver cirrhosis.

BACKGROUND AND PURPOSE: T1-weighted MR images show high signal intensity in the pallidum of many patients with liver cirrhosis. The purpose of this study was to evaluate quantitative changes in MR signals in patients with liver cirrhosis by using the magnetization transfer technique. METHODS: Magnetization transfer ratios were measured in seven different regions of the brain in 37 patients with liver cirrhosis and in 37 healthy volunteers. RESULTS: The magnetization transfer ratios in patients with liver cirrhosis were significantly lower than those in control subjects in the globus pallidus, putamen, thalamus, corona radiata, and subcortical white matter. CONCLUSION: Abnormal magnetization transfer ratios may be found in otherwise normal-appearing cerebral regions.

Brain↗
PubMed1998

PCR on cerebrospinal fluid to show influenza-associated acute encephalopathy or encephalitis.

BACKGROUND: Except for Reye's syndrome, influenza-associated acute encephalopathy or encephalitis is not universally recognised. We did a multicentre study of laboratory and clinical data for patients with influenza-associated acute encephalopathy or encephalitis. METHODS: In Nagoya, Japan, ten patients with acute encephalopathy or encephalitis associated with influenza-like illness were admitted to our hospitals between April, 1996, and March, 1997. We collected clinical, laboratory and serological data and assessed cerebrospinal fluid samples by PCR for influenza A and B. FINDINGS: Seven patients, aged 22 months to 4 years, had evidence of recent influenza infection, six with type-A/Hong Kong (H3N2) and one with type B. The first sign in the central nervous system appeared within 2 days of fever in all but one patient. The first sign of involvement of the central nervous system was generalised convulsions in all patients. Two patients died, one had sequelae, and four survived without sequelae. PCR for influenza type A was positive for five patients. INTERPRETATION: The results of PCR suggest that at least part of the influenza type A genome existed in the central nervous system. Influenza-associated acute encephalopathy or encephalitis in young children deserves wider recognition.

Acute Disease↗
PubMed1998

The Two Nuclei in the Dikaryon of the Homobasidiomycete Coprinus cinereus Change Position after Each Conjugate Division

We constructed a common-AB diploid strain of Coprinus cinereus and mated this to a compatible haploid strain to construct a diploid-haploid dikaryon. We examined the positions of the diploid and haploid nuclei in the apical and subapical cells of the dikaryon by fluorescence microscopy and microfluorometry. In 60% of apical cells the leading nucleus (the nucleus proximal to the hyphal apex) was diploid and the second nucleus (the nucleus distal to the apex) was haploid, whereas in the remaining 40% of apical cells the order of the two nuclei was reversed. It was also observed that in 97% of hyphae examined the order of the diploid and haploid nuclei was reversed between the apical cell and the subapical cell. Based on these observations, we conclude that the two nuclei alternate in taking the leading and second positions in the apical cell at almost every conjugate division in the dikaryon. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Hepatic cirrhosis: magnetisation transfer contrast in the globus pallidus.

The magnetisation transfer ratio (MTR), a quantitative tissue characteristic, and the pallidal index were measured in the globus pallidus of 37 patients with hepatic cirrhosis and 37 control subjects. The MTR decreased with severity of the disease, as indicated by the serum total bililubin, indocyanine green 15-min retention rate, and plasma ammonia. The pallidal index correlated significantly with haematological parameters, although the correlation coefficients tended to be lower than those between MTR and haematological parameters. This change in MTR corresponded to the results of the manganese chloride experiments. T1 shortening in the pallidum of patients with cirrhosis is presumably caused by paramagnetic effects, and possibly attributed to manganese deposition.

Case-Control Studies↗
PubMed1998

High-risk human papillomavirus infection and overexpression of p53 protein in squamous cell carcinoma of the esophagus from Japan.

The present study was undertaken in order to investigate the possible involvement of high-risk human papillomavirus (HPV; types 16 and 18) or the overexpression of p53 protein in 123 Japanese patients with esophageal squamous cell carcinoma (SCC) from five different institutions. We detected HPV DNA in 30.1% (37/123) by in situ hybridization (ISH). Of these 123 cases, HPV type 16 was detected in 22 cases and HPV type 18 in 23 cases. In addition, HPV types 16 and 18 were detected simultaneously in eight cases. We found an almost similar incidence of HPV infection at five different places in Japan. Then, among these patients, 24 fresh tumor samples were also examined for screening the presence of HPV DNA using dot blot hybridization (DBH) and polymerase chain reaction (PCR). We detected HPV DNA in 20.8% (5/24) by DBH and in 12.5% (3/24) by PCR. P53 protein overexpression was found in 34.1% (43/123) by immunohistochemistry (IHC). Furthermore, in 43 cases from Kochi Medical School, the group positive for p53 antibody statistically showed worse survival rate than the group negative for both HPV DNA and p53 antibody. Judging from these results obtained in the present study, HPV infection and p53 overexpression are frequently detected and involved in the carcinogenesis of esophageal SCC in Japan. We also found that no significant geographical difference of both HPV infection and p53 overexpression of esophageal SCC was seemingly present in Japan.

Aged↗
PubMed1998

Effect of multidisciplinary treatment with high dose rate intraluminal brachytherapy on survival in patients with unresectable esophageal cancer.

BACKGROUND: Since carcinoma of the esophagus is usually diagnosed at an advanced stage, many cases of esophageal cancer are beyond possible radical resection and only palliative treatment can be performed in such cases. Therefore, a great deal of discussion has taken place concerning indications for treatment modality, and various procedures have been performed to palliate such patients. The prognosis for such patients is still poor, even though many kinds of palliation have already been developed and applied. To improve the prognosis of such patients we developed a multidisciplinary treatment which includes high dose rate intraluminal brachytherapy (HDR-ILBRT) and evaluated its effectiveness, especially the HDR-ILBRT component. PATIENTS AND TREATMENT METHODS: Sixty-six patients with unresectable esophageal cancer enrolled in this study. Twenty-seven patients underwent bypass operations. Seven of the 27 patients received external irradiation only (group BE), 11 received external irradiation and HDR-ILBRT (group BEH), while the remaining 9 did not receive radiotherapy (group B). Another 39 patients without bypass operations were all treated with radiotherapy, 22 with external irradiation only (group E) and 17 were treated with external irradiation and HDR-ILBRT (group EH). After completion of radiotherapy, all patients received chemotherapy with 5-FU (2,500 mg/body) and CDDP (100 mg/body). RESULTS: Mean survival time and the 5-year survival rate of group BEH (13.3 +/- 1.5 months and 20%) were significantly improved compared with group BE + B (p < 0.05). In the patients without bypass operations, there were significant differences in the mean survival time and the 3-year survival rate in groups EH and E (group EH 16.5 +/- 2.5 months, 21.8%, group E 9.0 +/- 1.3 months, 0%, p < 0.05). The bypass operation itself and chemotherapy did not significantly affect the prognosis of patients with unresectable esophageal cancer. CONCLUSION: These results strongly suggest the use of HDR-ILBRT, as a component of multidisciplinary treatment for unresectable esophageal cancer, was significantly effective and HDR-ILBRT contributed to improve outcomes in patients with advanced esophageal cancer. HDR-ILBRT should be established as a component of treatments for unresectable esophageal cancer.

Aged↗
PubMed1998

[A case of identification of two persons from heavily burned teeth by age estimation].

A man murdered his two daughters, one five years and two months old and one seven months old. He placed them into a 750 degrees C aluminum liquefying furnace. Teeth and many fragments of the severely burned bones were recovered. However, at first, the bone fragments did not offer proof that two children were put into the furnace. The age estimation of the teeth burned in liquefied aluminum was carried out based on the maturity of the teeth and the degree of absorption of deciduous teeth roots. As a result from the admixture of permanent teeth and deciduous teeth, we presumed them to be derived from more than one person.

Age Determination by Teeth↗
PubMed1997

Use of high-performance liquid chromatography as an extraction procedure for analysis of triazolam in decomposed human muscle by gas chromatography-mass spectrometry.

A reliable and sensitive method for the determination of triazolam in human muscle using gas chromatography-mass spectrometry (GC-MS) is described. The drug was extracted from decomposed human muscle using three-step liquid-liquid extraction and HPLC which was performed isocratically on a conventional ODS column with a mobile phase of 0.01 M phosphate buffer (pH 6.5)-acetonitrile (7:3). Estazolam was used as an internal standard. GC-MS analysis was performed on a DB-5 capillary column. Excellent linearity was obtained over the concentration range 1-200 ng/g. The lower limit of detection was approximately 0.5 ng/g. Forensic application of the present method was also described.

Chromatography, High Pressure Liquid↗
PubMed1997

Sensitive detection of human globin chains by microbore high-performance liquid chromatography and its forensic application.

This paper describes a simple and sensitive high-performance liquid chromatographic (HPLC) method for the detection of human globin chains in blood and bloodstains. The method involves direct injection of the filtered samples of dilute hemolysates or bloodstain extracts onto a microbore C4 reversed-phase column (2.1 mm I.D.) with UV detection at 220 nm. Microbore HPLC offers a significant improvement in sensitivity with little loss of the resolution of globin chains and only small variations in the determination of gamma chain composition. The detection limit of hemoglobin (Hb) was 0.1 microgram, which is equivalent to about 1 nl of fresh whole blood. Umbilical cord blood could be differentiated from adult blood in stains that were up to twenty weeks old, by the presence of gamma globin chains. The present method will be useful for detection of abnormal Hbs and for the determination of gamma chain composition in clinical laboratories, as well as in the practice of forensic science for the analysis of minute amounts of blood and bloodstains.

Blood Stains↗
PubMed1997

Genetic variation at five STR loci in subpopulations living in Turkey.

Five short tandem repeat (STR) systems HumVWA, HumTH01, HumCD4, HumF13B and HumFES were investigated in 2 subpopulations living in Turkey (Laz Turks and Kurds). The population genetic data were compared to a Turkish population sample from the Adana area. A closer genetic relationship was found to the Laz Turks than to the Kurdish sample which was also confirmed by phylogenetic tree reconstruction with seven populations from three major ethnic groups (Caucasian, Asian and African). In contrast to the Laz and Adana populations the Kurdish sample showed relatively low heterozygosity values and deviations from Hardy-Weinberg equilibrium in four of the five systems.

Alleles↗
PubMed1997

The well-balanced nucleoside-nucleotide mixture "OG-VI" for special medical purposes.

Nucleotides and nucleosides are essential components in all cells. However, nucleotides have not been supplied in parenteral nutrition regimens. We developed a well-balanced nucleoside-nucleotide mixture "OG-VI" and examined its effect in animals under some stressed conditions. OG-VI was composed of 30 mmol/l of inosine, 30 mmol/l of guanosine monophosphate, 30 mmol/l of cytidine, 22.5 mmol/l of uridine and 7.4 mmol/l of thymidine. The whole body protein turnover increased significantly in rats receiving total parenteral nutrition (TPN) with OG-VI solution after 70% hepatectomy, compared with rats receiving normal TPN without OG-VI (122.1 +/- 20.9 mgN.kg-1.h-1 vs. 97.4 +/- 10.1 mgN.kg-1.h-1, P < 0.01, n = 10). OG-VI significantly enhanced protein synthesis while it did not decrease protein breakdown. The effect of OG-VI on myocardium after hypoxic challenge was also examined in rats. The creatine phosphate (PCr)/inorganic phosphate (Pi) was decreased in normal rat myocardium after hypoxic challenge. However, in the rats administered OG-VI, PCr/Pi was maintained at baseline level and did not decrease after hypoxia. There was no significant change in the level of adenosine triphosphate (ATP) between before and after hypoxic challenge in myocardium of the rats administered OG-VI. In the rats receiving normal saline, instead of OG-VI, the ATP level decreased significantly after hypoxic challenge (4132 +/- 276 nmol/g tissue, n = 3, vs. 3439 +/- 465 nmol/g tissue, n = 5, P < 0.05). These data suggested that the well-balanced nucleoside-nucleotide mixture, OG-VI improved nitrogen metabolism and might stimulate synthesis of high-energy phosphate in recovery after severe surgical stress.

Animals↗