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Biomedical subjects

Noriaki Ikeda

Publications and source records attributed to Noriaki Ikeda.

At least 19 recordsLinked to original sources
PubMed2007

Unusual death of a baby: a dog attack and confirmation using human and canine STRs.

We performed an autopsy on a 3-month-old baby boy who had only one area severe and extensive wound to his head and face. Three unrelated miniature dachshunds were in the house. After our investigation, we were able to confirm that the wound had in fact been caused by a dog attack, and we were able to identify the offending dog among the three dogs using both human and canine short tandem repeat obtained from samples taken from the suspected dog and from the scene of the attack.

Animals↗
PubMed2006

A fatal case of amoxapine poisoning under the influence of chronic use of psychotropic drugs.

A 43-year-old woman was found dead in a car in the supine position. She had been suffering from depression for 2 years and hesitation wounds on the left forearm and wrist were observed. On microscopic examination, pulmonary congestion and edema were observed with heart failure cells in many alveoli, thereby suggesting not only acute but also chronic heart failure. Drug screening in the blood by gas chromatography-mass spectrometry (GC-MS) revealed the presence of amoxapine and levomepromazine, and their concentrations in tissues were determined by GC-MS with three-step solvent extraction followed by acetylation. The concentration of amoxapine in the blood and liver was 0.86-1.77 and 18.76microg/ml, respectively; the levels were much higher than the therapeutic level but did not reach the lethal level. The concentrations of levomepromazine in tissues were within the therapeutic level. Based on the pathological and toxicological findings, the cause of death was determined to be amoxapine poisoning on the basis of chronic heart failure due to the chronic use of psychotropic drugs.

Adult↗
PubMed2006

Development and validation of MIX: comprehensive free software for meta-analysis of causal research data.

BACKGROUND: Meta-analysis has become a well-known method for synthesis of quantitative data from previously conducted research in applied health sciences. So far, meta-analysis has been particularly useful in evaluating and comparing therapies and in assessing causes of disease. Consequently, the number of software packages that can perform meta-analysis has increased over the years. Unfortunately, it can take a substantial amount of time to get acquainted with some of these programs and most contain little or no interactive educational material. We set out to create and validate an easy-to-use and comprehensive meta-analysis package that would be simple enough programming-wise to remain available as a free download. We specifically aimed at students and researchers who are new to meta-analysis, with important parts of the development oriented towards creating internal interactive tutoring tools and designing features that would facilitate usage of the software as a companion to existing books on meta-analysis. RESULTS: We took an unconventional approach and created a program that uses Excel as a calculation and programming platform. The main programming language was Visual Basic, as implemented in Visual Basic 6 and Visual Basic for Applications in Excel 2000 and higher. The development took approximately two years and resulted in the 'MIX' program, which can be downloaded from the program's website free of charge. Next, we set out to validate the MIX output with two major software packages as reference standards, namely STATA (metan, metabias, and metatrim) and Comprehensive Meta-Analysis Version 2. Eight meta-analyses that had been published in major journals were used as data sources. All numerical and graphical results from analyses with MIX were identical to their counterparts in STATA and CMA. The MIX program distinguishes itself from most other programs by the extensive graphical output, the click-and-go (Excel) interface, and the educational features. CONCLUSION: The MIX program is a valid tool for performing meta-analysis and may be particularly useful in educational environments. It can be downloaded free of charge via http://www.mix-for-meta-analysis.info or http://sourceforge.net/projects/meta-analysis.

Causality↗
PubMed2006

Development of an alarm sound database and simulator.

OBJECTIVES: The purpose of this study was to develop an interactive software package of alarm sounds to present, recognize and share problems about alarm sounds among medical staff and medical manufactures. METHODS: The alarm sounds were recorded in variable alarm conditions in a WAV file. The alarm conditions were arbitrarily induced by modifying attachments of various medical devices. The software package that integrated an alarm sound database and simulator was used to assess the ability to identify the monitor that sounded the alarm for the medical staff. RESULTS: Eighty alarm sound files (40MB in total) were recorded from 41 medical devices made by 28 companies. There were three pairs of similar alarm sounds that could not easily be distinguished, two alarm sounds which had a different priority, either low or high. The alarm sound database was created in an Excel file (ASDB.xls 170 kB, 40 MB with photos), and included a list of file names that were hyperlinked to alarm sound files. An alarm sound simulator (AlmSS) was constructed with two modules for simultaneously playing alarm sound files and for designing new alarm sounds. The AlmSS was used in the assessing procedure to determine whether 19 clinical engineers could identify 13 alarm sounds only by their distinctive sounds. They were asked to choose from a list of devices and to rate the priority of each alarm. The overall correct identification rate of the alarm sounds was 48%, and six characteristic alarm sounds were correctly recognized by beetween 63% to 100% of the subjects. The overall recognition rate of the alarm sound priority was only 27%. CONCLUSIONS: We have developed an interactive software package of alarm sounds by integrating the database and the alarm sound simulator (URL: http://info.ahs.kitasato-u.ac.jp/tkweb/alarm/asdb.html ). The AlmSS was useful for replaying multiple alarm sounds simultaneously and designing new alarm sounds interactively.

Biomedical Engineering↗
PubMed2006

Relationship between pulmonary fat embolism and core body temperature in rats with a severe fatty liver.

We previously demonstrated that pulmonary fat embolism was induced by elevation of the core body temperature, in rats with a fatty liver. The aim of the present examination was to investigate the core body temperature at which pulmonary fat embolism developed capillaries through exposure to a high temperature, in rats with a fatty liver. Following heat stress, pulmonary fat embolism was observed to a slight degree at a core body temperature of 41 and 42 degrees C, whereas the severity of pulmonary fat embolism was greatly increased and was classified as severe at a core body temperature of 43 degrees C. Moreover, the concentrations of aspartate aminotransferase and alanine aminotransferase within plasma were significantly increased at a core body temperature of 43 degrees C. These results clearly indicate that the development of pulmonary fat embolism could be related to hyperthermia at above 42 degrees C following heat stress, and that fat emboli may be derived from the fatty liver itself. It is thus likely that pulmonary fat embolism can be considered as one form of evidence of hyperthermia in an individual with a fatty liver.

Animals↗
PubMed2006

Methamphetamine-related sudden death with a concentration which was of a 'toxic level'.

We reviewed 32 cases where a forensic autopsy detected methamphetamine in the blood, and all of these autopsies were performed at two institutes between 1991 and 2003. In accordance with several criteria, the blood concentration in 11 cases was classified as above the toxic level, and 10 of these cases were diagnosed as methamphetamine poisoning. In 20 cases (62.5% of total cases), the blood concentration was of a 'toxic level', and 10, 2 and 1 of these cases were diagnosed as methamphetamine poisoning, cardiomyopathy and intracerebral hemorrhage, respectively. Since it is unclear how the effects of methamphetamine may contribute to the death of an individual, a diagnosis of the exact cause of death is often difficult to make in cases where the blood concentration of methamphetamine was of a 'toxic level'. Therefore, a diagnosis has to be carefully made in consideration of the pathological findings, the pharmacological effects of methamphetamine and the process until death in such cases. Additionally, the mechanism of methamphetamine-related death needs to be more fully studied to enable an appropriate diagnosis to be made easily.

Adult↗
PubMed2006

Vulnerability of experimentally induced fatty liver to heat stress in rats.

BACKGROUND: The aim of this study was to confirm the vulnerability of fatty liver to heat stress using fatty liver rats from the viewpoint of the induction of apoptosis. METHODS: We exposed rats with and without a fatty liver to heat stress and then looked for apoptotic cells within the liver tissue using two apoptosis detection kits. We also determined the mRNA expression of heat shock protein (HSP) 70, caspase-3, bcl-2, and bax using a quantitative reverse transcription-polymerase chain reaction method. RESULTS: Following heat stress, apoptosis was strongly visible in the fatty liver comparing with that noted in the normal liver. The expression of HSP70 was increased following heat stress in both livers, but the volume of its expression was significantly less in the fatty liver than in the normal liver. The ratio of bcl-2/bax expression tended to increase in the normal liver but decrease in the fatty liver following heat stress. Caspase-3 demonstrated no significant change following heat stress in both livers. CONCLUSIONS: The detection of apoptosis, together with changes in the mRNA expression of HSP70 and the expression ratio bcl-2/bax mRNA may indicate vulnerability of a fatty liver to heat stress and may support the hypothesis that morphologic change is induced in a fatty liver by exposure to heat stress. These results suggest that fatty liver may be more vulnerable to heat stress than normal liver.

Animals↗
PubMed2006

High-performance liquid chromatographic-mass spectrometric determination of methamphetamine and amphetamine enantiomers, desmethylselegiline and selegiline, in hair samples of long-term methamphetamine abusers or selegiline users.

We devised a highly sensitive method for simultaneously determining methamphetamine (MA) and amphetamine (AP) enantiomers, desmethylselegiline (DMSG) and selegiline (SG), in human hair using a derivatization technique and high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS). MA and AP enantiomers and DMSG were effectively converted to trifluoroacetic acid (TFA) derivatives, and the sensitivity of MA and DMSG increased five times over compared with that of free bases. The TFA derivatives of each compound were stable within one week in a stock solution of methanol or for 24 h in the HPLC mobile phase (mixture of methanol and ammonium formate buffer). Each compound was well separated, and calibration curves were linear in the concentration range 0.04-40 ng/mg for MA enantiomers, SG and DMSG, and 0.2-40 ng/mg for AP enantiomers. The accuracy and precision of the method were evaluated, and relative standard deviations were within 7%. Our method was successfully applied to hair samples obtained from long-term MA abusers and SG users. (+)-MA and (+)-AP were detected from three MA abusers at concentrations of 0.79-20.85 and 0.04-3.30 ng/mg, respectively. On the other hand, (-)-MA, (-)-AP, DMSG, and SG were detected in three SG users at concentrations of 2.48-9.05, 0.72-3.10, 0.12-0.59, and 0-0.04 ng/mg, respectively. Based on our obtained data, discrimination of MA abusers from SG users was considered to be possible by comparing optical isomers of MA and AP, the existence of DMSG and/or SG, and the concentration ratio of AP to MA in hair samples.

Amphetamine↗
PubMed2006

Rapid screening for and simultaneous semiquantitative analysis of thirty abused drugs in human urine samples using gas chromatography-mass spectrometry.

In Japan, a wide variety of designer drugs became popular among juveniles because of their availability via the Internet and mobile phones. Hence, it is necessary to develop simple and rapid screening method for these drugs. We devised a rapid screening method for and simultaneous semiquantitative analysis of 30 abused drugs, including amphetamines, amphetamine-, piperazine-, tryptamine-, and phenethylamine-derived designer drugs and opiates in human urine. The urine sample was digested with urease, and the drugs were analyzed by gas chromatography-mass spectrometry in the scan mode after solid-phase extraction with a Focus column and acetylation. The retention time obtained with the use of a retention time locking technique and three qualifier ions were used to obtain positive results. As the Focus column requires only simple extraction steps and can retain various drugs of a wide range of polarity, screening of 30 abused drugs was feasible within 3 h. The calibration curves were linear in the concentration range of 100-5,000 ng/mL in most drugs with correlation coefficients exceeding 0.99. The absolute recoveries for all drugs in urine samples were 6.9-125.4% at the concentration 1,000 ng/mL. This method will be most useful to confirm the presence of many abused drugs in urine in clinical and forensic cases.

Amphetamines↗
PubMed2006

Relationship between cardiopulmonary resuscitation and injuries of the cardiac conduction system: pathological features and pathogenesis of such injuries.

OBJECTIVE: The purpose of this study was to assess the incidence, features, and pathogenesis of microscopic injuries to the cardiac conduction system caused by cardiopulmonary resuscitation. DESIGN: : Prospective study. SETTING: Autopsy unit of the university. PATIENTS: Victims who had been transferred to the emergency room due to cardiac arrest arising from nontraumatic cause plus age-matched control patients. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: The cardiac conduction system of 80 hearts without gross injury from patients who had received cardiopulmonary resuscitation due to nontraumatic causes was examined. Of these 80 patients, seven (9%) showed fresh injuries, including a lesion that had gone unreported in the previous literature. Localized hemorrhage without inflammatory reaction was evident in six of these patients. Three of the six patients showed hemorrhage in the sinoatrial node, whereas the other three patients showed hemorrhage in the atrioventricular conduction system. The remaining one patient showed localized dissection of the atrioventricular node artery with the appearance of red blood cells in the false lumen. There was no significant difference with regard to age, gender, cause of cardiopulmonary arrest, whether victim had received electrical shock treatment, whether victim had received anticoagulants, and the duration of cardiopulmonary resuscitation between the seven patients with fresh injuries and the other 73 patients. Fracture of the sternum or rib was found in only one of the seven patients but in 14 of the 73 patients. No pathologic lesions were found in the 30 control patients who did not receive cardiopulmonary resuscitation. CONCLUSIONS: It can be presumed that injuries to the conduction system do occur in limited regions during cardiopulmonary resuscitation. Minute differences in the location of the cardiac silhouette or cardiac conduction system also need to be considered, rather than just the severity of force to the anterior chest, when determining the pathogenesis of these injuries.

Adult↗
PubMed2006

Evaluation of exercise-induced T wave changes in patients with idiopathic dilated cardiomyopathy before and after beta-blocker therapy.

INTRODUCTION: Ventricular repolarization abnormalities are thought to contribute to lethal ventricular arrhythmias in patients with idiopathic dilated cardiomyopathy (DCM). The purpose of this study was to evaluate exercise-induced T wave changes in DCM patients before and after beta-blocker therapy to investigate repolarization abnormalities. METHODS AND RESULTS: Treadmill exercise testing was performed in 20 DCM patients and 50 normal subjects. T wave amplitude (TA: baseline to T wave apex; mV) and recovery time (RT: QRS onset to the maximum dV/dt point of the T wave; msec) were measured before and 1 minute after peak exercise. TA was averaged in the right and left precordial leads (TA(V1-3), TA(V4-6)). RT was normalized to the maximum QT interval in the 12-lead ECG and expressed as the %RT (%RT). %RT was also averaged in the precordial leads (%RT(V1-3), %RT(V4-6)). After exercise, TA increased and %RT decreased in both groups. In DCM patients, TA(V1-3) was greater and TA(V4-6) was less than in normal subjects before and after exercise. There was no difference in %RT(V1-3) between the groups, but %RT(V4-6) was greater in DCM patients both before and after exercise. DCM patients repeated the same evaluation after 6 months of oral beta-blocker therapy. Compared with measurements before beta-blocker therapy, TA(V1-3) and %RT(V1-3) did not change. However, TA(V4-6) increased and %RT(V4-6) decreased significantly both before and after exercise. CONCLUSION: DCM patients showed small TA and large %RT in the left precordial leads at rest as well as after exercise. Chronic beta-blocker therapy in DCM patients normalized these ventricular repolarization abnormalities.

Adrenergic beta-Antagonists↗
PubMed2006

Homicidal sharp force injuries inflicted by family members or relatives.

We retrospectively reviewed 35 autopsy cases where death had resulted from homicidal sharp force injuries and compared cases where the injuries had been inflicted by family members or relatives (relative group) with cases where the injuries had been inflicted by an unrelated person (stranger group). We reviewed the age and sex of the victims, the number of stab wounds, the site of the stab wounds, the presence of defence wounds, the detection of alcohol and other drugs and the mental status of the victims and perpetrators. We found the following tendencies: (a) a female victim was more frequently killed by a relative than by a stranger; (b) the percentage of cases receiving a single stab wound and the percentage of cases receiving more than ten stab wounds were both unexpectedly higher in the relative group than in the stranger group, and (c) in the stranger group, when there were no defence wounds, the victim had usually consumed alcohol, whereas when there were neither defence wounds nor alcohol intake, the case usually fell into the relative group. These tendencies will contribute towards our forensic appraisement in autopsy cases resulting from sharp force injuries.

Adult↗
PubMed2005

Simple and sensitive determination of free and total morphine in human liver and kidney using gas chromatography-mass spectrometry.

We developed a reliable, simple and sensitive method to determine free and total morphine in human liver and kidney, using gas chromatography-mass spectrometry (GC-MS). Free morphine or total morphine obtained by acid hydrolysis from 0.2g tissue sample was extracted using an Extrelut NT column with an internal standard, dihydrocodeine, followed by trimethylsilylation. The derivatized extract was submitted to GC-MS analysis of EI-SIM mode. The calibration curves of morphine in both liver and kidney samples were linear in the concentration range from 0.005 to 5 microg/g. The lower limits of detection of morphine were 0.005 microg/g. This method proved successful when we determined free and total morphine in liver and kidney obtained from an autopsied man who was mis-ingested morphine compound in the hospital, which resulted in the cause of death being morphine intoxication.

Analgesics, Opioid↗
PubMed2005

Analysis of mutation of the plasma cholinesterase gene in a man who had died following a traffic accident.

We analyzed mutation of the butyrylcholinesterase (BCHE) gene in a 69-year-old man on whom a forensic autopsy had been performed after he had died following a traffic accident. Extremely low plasma cholinesterase activity had been pointed out by the emergency doctor at the hospital prior to his death and based on this, organophosphorus poisoning had been suspected. However, no pesticides, which could have reduced the plasma cholinesterase activity, were detected by toxicological analysis using GC/MS. Subsequently, one base insertion was found in exon 2. The frame shift mutation had occurred because a homozygous extra T had been inserted between nucleotides 1343 and 1344, resulting in the appearance of a stop codon in codon 454 (AGA454TAA, Arg454stop). This heterozygous frame shift mutation at this point was identified in the man's son. It is likely that there may be many such latent patients with abnormal plasma cholinesterase activity, and accordingly we should always bear this fact in mind and should carry out molecular genetic testing for an accurate diagnosis of this deficiency.

Accidents, Traffic↗
PubMed2005

Prolonged recovery time in the left precordial leads reflects increased left ventricular mass in the hypertensive patients.

Hypertensive left ventricular hypertrophy (LVH) is considered to be a risk for arrhythmogenicity, but the quantification of the changes in T-wave morphology, as the reflection of repolarization abnormality, has not been fully established. The purpose of this study was to quantify the T-wave changes in the hypertensive patients and to investigate the relationship with the increased left ventricular mass. Standard 12-lead electrocardiogram and echocardiogram were recorded in 90 hypertensive patients. Activation time (AT), activation recovery interval (ARI), and recovery time (RT) were measured in the precordial lead and QT interval in the 12 leads. To compare the left precordial T-wave changes among patients, measurements of ARI and RT in the right precordial negative T wave were excluded. Each parameter excluding AT was corrected with Bazett formula, and then the dispersion was calculated. Left ventricular mass index was determined echocardiographically to select non-LVH group (n=31) and LVH group (n=59). In both groups, AT, ARI, and RT in the left precordial leads were larger compared with those in the right precordial leads. Dispersion of AT was not different between the 2 groups. However, the dispersion of ARI and RT in LVH group was significantly greater than that in non-LVH group. There were correlations between left ventricular mass index and the dispersion of RT (r=0.66, P<.001), ARI (r=0.61, P<.001), and 12-lead QT (r=0.42, P<.001). In patients with LVH, significant prolongation of RT in the left precordial leads was observed, suggesting that this RT change resulted from the nonuniformity of epicardial action potential duration.

Arrhythmias, Cardiac↗
PubMed2005

Syntheses and properties of emissive iridium(III) complexes with tridentate benzimidazole derivatives.

A series of novel emissive Ir(III) complexes having the coordination environments of [Ir(N--N--N)2]3+, [Ir(N--N--N)(N--N)Cl]2+, and [Ir(N--N--N)(N--C--N)]2+ with 2,6-bis(1-methyl-benzimidazol-2-yl)pyridine (L1, N--N--N), 1,3-bis(1-methyl-benzimidazol-2-yl)benzene (L2H, N--C--N), 4'-(4-methylphenyl)-2,2':6',2' '-terpyridine (ttpy, N--N--N), and 2,2'-bipyridine (bpy, N--N) have been synthesized and their photophysical and electrochemical properties studied. The Ir(III) complexes exhibited phosphorescent emissions in the 500-600 nm region, with lifetimes ranging from approximately 1-10 micros at 295 K. Analysis of the 0-0 energies and the redox potentials indicated that the lowest excited state of [Ir(L1)(L2)]2+ possessed the highest contribution of 3MLCT (MLCT = metal-to-ligand charge transfer) among the Ir(III) complexes, reflecting the sigma-donating ability of the tridentate ligand, ttpy < L1 < L2. The emission quantum yields (phi) of the Ir(III) complexes ranged from 0.037 to 0.19, and the highest phi value (0.19) was obtained for [Ir(L1)(bpy)Cl]2+. Radiative rate constants (k(r)) were 1.2 x 10(4) s(-1) for [Ir(ttpy)2]3+, 3.7 x 10(4) s(-1) for [Ir(L1)(bpy)Cl]2+, 3.8 x 10(4) s(-1) for [Ir(ttpy)(bpy)Cl]2+, 3.9 x 10(4) s(-1) for [Ir(L1)2]3+, and 6.6 x 10(4) s(-1) for [Ir(L1)(L2)]2+. The highest radiative rate for [Ir(L1)(L2)]2+ with the highest contribution of 3MLCT could be explained in terms of the singlet-triplet mixing induced by spin-orbit coupling of 5d electrons in the MLCT electronic configurations.

Journal Article↗