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Biomedical subjects

M Yashiki

Publications and source records attributed to M Yashiki.

At least 37 records · Page 2Linked to original sources

Lack of effect of transmembrane gradient of magnesium and sodium on regulation of cytosolic free magnesium concentration in rat lymphocytes.

The regulation of the intracellular concentration of Mg2+ ([Mg2+]i) is not fully understood. The level of Mg in lymphocytes is a good predictor of total body Mg status. We measured [Mg2+]i and total Mg in rat lymphocytes by using, respectively, the fluorescent Mg2+ indicator mag-fura-2 and atomic absorption spectrophotometry. The basal [Mg2+]i in rat lymphocytes was 328 +/- 23 micromol/l. An elevation to 5 mmol/l or the removal of extracellular Mg2+ did not affect [Mg2+]i. A reduction in extracellular Na+ did not influence [Mg2+]i for 60 min. The total Mg concentration in lymphocytes also remained stable. Results suggest that the permeability of the plasma membrane to Mg2+ is very low, and that Na+/Mg2+ exchange is not involved in the regulation of [Mg2+]i in rat lymphocytes.

Animals↗

Rapid analysis of malathion in blood using head space-solid phase microextraction and selected ion monitoring.

A simple and rapid method for analysis of malathion in blood was developed using head space-solid phase microextraction (HS-SPME) and gas chromatography mass spectrometry/ electron impact ionization-selected ion monitoring (GC-MS/EI-SIM). A vial containing a blood sample, ammonium sulphate, sulphuric acid and fenitrothion as an internal standard, was heated at 90 degrees C for 15 min. The extraction fiber of the SPME was exposed for 5 min in the head space of the vial. The compounds absorbed on the fiber were detached by exposing the fibre in the injection port of GC-MS. A straight calibration curve was obtained between malathion concentrations of 2.5 to 50.0 micrograms g-1 in blood. No interfering substances were found, and the time for analysis was 40 min for one sample.

Adult↗

A fatal case of drinking and cyanamide intake.

A 34-year-old housewife with alcohol dependence vomited severely, lost consciousness, and died after she took more than 20 ml of 1% calcium cyanamide, and alcoholic beverage containing about 129 g of ethyl alcohol. An autopsy was performed around 16 h after death. The body weighed 55.5 kg, and moderate lung edema was found. Ethanol concentrations were 4.24 mg/g in the left heart blood, 4.39 mg/g in the right heart blood, and 21.55 mg/g in the stomach contents. Cyanamide concentrations were 0.63 microgram/g in the left heart blood, 0.20 microgram/g in the right heart blood, and 0.22 microgram/g in the stomach contents. The cause of death was determined to be acute ethanol intoxication with alcohol-cyanamide reaction.

Adult↗

Rapid quantitative analysis of oleandrin in human blood by high-performance liquid chromatography.

A simple and rapid method for quantitation of oleandrin in human blood has been developed using an Extrelut column and high-performance liquid chromatography (HPLC). Blood samples spiked with oleandrin were mixed with distilled water and applied to an Extrelut column for elution with ethyl acetate before HPLC. The HPLC separation of the compound from endogeneous impurities was generally satisfactory with the use of a reversed-phase column. Oleandrin showed excellent linearity in the range of 0.05-10 micrograms/g and the limit of detection was 0.02 microgram/g for human blood. The recovery of the compound, which had been spiked to human blood, was more than 90%. The present method is simple and more rapid than those so far reported, and seems useful for analysis of oleandrin in the cases of oleander poisoning.

Cardenolides↗

Rapid analysis of amphetamines in blood using head space-solid phase microextraction and selected ion monitoring.

A simple and rapid method for analysis of methamphetamine (MA) and amphetamine (AP) in blood was developed using head space-solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry/electron impact ionization-selected ion monitoring (GC-MS/EI-SIM). A vial containing a blood sample, sodium hydroxide, and pentadeuterated methamphetamine as an internal standard, was heated at 80 degrees C for 20 min. The extraction fiber of the SPME was exposed for 5 min in the head space of the vial. First, heptafluorobutyric anhydride solution was injected into the injection port of the GC-MS to make heptafluorobutyramide (HFB) derivatives of amphetamines, and compounds absorbed on the fiber were detached by exposing the fiber in the injection port. Straight calibration curves of MA and AP were obtained from 0.01 to 2 micrograms/g in blood, respectively. No interfering substances were found, and the time for analysis was 30 min for one sample.

Adult↗

[A case of death due to mitral regurgitation caused by traumatic mitral valve injury].

A 51-year-old male, who had been driving a motor bicycle, was involved in a traffic accident with a trailer, and he died immediately after the accident. According to the external examination of the victim, no fatal injuries were found. The medico-legal autopsy revealed a rupture of the left side of the pericardium, and a tear of the posterior leaflet of the mitral valve. There were no injuries of the papillary muscles and chordae. The cause of death was due to traumatic mitral regurgitation.

Accidents, Traffic↗

Detection of amphetamines in urine using head space-solid phase microextraction and chemical ionization selected ion monitoring.

An accurate, simple and rapid method for qualitative and quantitative analysis of amphetamine and methamphetamine in urine was developed using head space-solid phase microextraction and gas chromatography-mass spectrometry/chemical ionization selected iron monitoring. A vial containing a urine sample potassium carbonate and pentadeuterated methamphetamine which was used as an internal standard was heated at 80 degrees C for 20 min. The needle of a solid phase microextraction device was passed through the septum, and the extraction fiber in the needle was exposed for 5 min in the head space of the vial. The needle was removed from the vial and inserted into the injection port of gas chromatograph or gas chromatograph/mass spectrometer. The compounds adsorbed on the fiber were detached by exposing the fiber in the injection port, and analyzed. The proposed method was more than 20 times more sensitive than the conventional head space method.

Amphetamine↗

A rapid method for detecting barbiturates in serum using EI-SIM.

A simple and rapid method for analysis of barbiturates in serum has been developed. In order to extract and clean barbiturates in serum, a separation column packed with Extrelut and Florisil was used, and the eluate was directly analyzed by means of electron impact selected ion monitoring (EI-SIM). Selected ions used were base peak ions of 10 barbituartes, and the internal standard used was allobarbital or secobarbital. The calibration curves were linear over the range 0.5-5 ng. Extraction of replicate serum samples containing 20 micrograms/1.5 ml and 5 micrograms/1.5 ml resulted in a recovery of 87.2-105.2% and 81.6-104.6%, respectively, with the exception of phenobarbital, which was 151.9% and 172.1%, respectively. Secobarbital was also analyzed in the serum of 13 patients who had been given secobarbital intravenously. In 3 out of 10 cases, secobarbital levels greater than 1 micrograms/ml were detected more than 72 h after administration. This method seems to have possibilities for clinical use.

Adult↗

Site dependence of methamphetamine concentrations in blood samples collected from cadavers of people who had been methamphetamine abusers.

Various blood samples were collected from heart cavities and blood vessels in eight autopsy cases of people who had been methamphetamine abusers. Methamphetamine and its metabolite, amphetamine, were determined by gas chromatography-mass spectrometry-selected ion monitoring. In four cases where left and right heart blood samples were collected, methamphetamine concentrations in the left heart blood samples were 1.9-2.6 times higher than those in the right heart blood samples. In three cases where pulmonary vein blood samples were collected, methamphetamine concentrations in the pulmonary vein blood samples were higher than those in other blood samples sites. To interpret the blood methamphetamine concentrations, site dependence should be taken into consideration.

Adult↗

Interpretation of COHb concentrations in the left and right heart blood of cadavers.

Carbon monoxide hemoglobin (COHb) concentrations in left and right heart blood samples from cadavers both exposed and not exposed to fire or CO gas were analyzed by the gas chromatographic method. The COHb concentration ratio between samples of left and right heart blood (L/R ratio) does not appear to be useful for establishing whether death has occurred before or after exposure to fire with the exception of cases where no soot can be detected in the airways by the naked eye and the COHb concentration in the blood sample is within the level considered normal for tobacco smokers.

Adolescent↗

Discrepancy between estimated and actual time elapsed after death of a severed head.

A severed head which had been wrapped in seven plastic bags and set in concrete in an airtight insulated plastic box was found approximately 22 months after the occurrence of death. Ammonium magnesium phosphate had formed and on the basis of this and other observed postmortem changes, time elapsed after death was estimated to be from 2 weeks to 6 months. The absence of oxygen is thought to have contributed significantly to the great discrepancy between estimated and actual time elapsed after death.

Adult↗

[Analysis of thinner components using the Curie-point pyrolyzer-gas chromatographic method in the tissues of a victim fatally poisoned].

A 43-year-old male was found dead in the trunk of his car which was filled with thinner vapor. Thinner components in the tissues were analyzed using a gas chromatograph equipped with Curie-point pyrolyzer (Py-GC), and a gas chromatograph-mass spectrometer. The Py-GC method was able to analyze with very small materials. It was simple and quick but not as sensitive as the head-space gas chromatographic method. Toluene, ethylbenzene and xylenes were detected in the tissues, and their presence was confirmed by gas chromatography-mass spectrometry. The concentrations of toluene, ethylbenzene and xylenes in blood and the brain were 56.8, 6.8 and 4.5 micrograms/ml; and 203, 43.5 and 33.9 micrograms/g, respectively. The cause of death was thus judged as be thinner poisoning.

Adult↗

[A fatal case caused by organophosphorus insecticide intoxication and confirmed by the metabolite found in the blood].

An 83-year-old woman and two other members of her family were poisoned after eating lettuce prepared with Ethimethon Granule 6 instead of salt by mistake. Ethimethon Granule 6 is a mixture of organophosphorus pesticides, disulfoton and diazinon. All three were admitted to a hospital, and she died 22 h after ingestion and the others recovered. Disulfoton and diazinon in the remaining lettuce were detected and confirmed by gas chromatography-mass spectrometry. The pesticides, however, were not detected in the blood sample collected from the victim at autopsy. A metabolite of disulfoton, phosphorothiolate sulfone, was detected by FPD-gas chromatography, and confirmed by gas chromatography-mass spectrometry.

Aged↗

[A case of suicide by an intravenous injection of pancuronium].

A 25-year-old male anesthesiologist was found dead in his room with an intravenous drip line connected with his leg. There were several empty ampules of pancuronium, midazolam and buprenorphine around him. Pancuronium and midazolam in the blood and urine samples collected at postmortem examination were detected by spectrofluorometry and ECD-gas chromatography, respectively. The concentrations of pancuronium and midazolam were 0.3 micrograms/g and 0.12 micrograms/g in the blood, respectively; 0.9 micrograms/g and 0.05 micrograms/g in the urine, respectively. The cause of death was determined to be asphyxia due to respiratory muscle paralysis caused by pancuronium.

Adult↗

[Asphyxial death by laryngopharyngeal tumor--two autopsy cases].

Case 1. A 44-year-old male died about 3 h after paracenteses of both palatine tonsils. A 6.5 x 2.5 x 2.0 cm tumor, caused by bleeding and edema, was revealed at medico-legal autopsy. This tumor extended from the right palatine tonsil to the right edge of epiglottis. The cause of death was determined to be acute asphyxia due to the obstruction of the airway by the tumor. Case 2. A 51-year-old female was thought to have been killed by manual strangulation. At medico-legal autopsy, three malignant tumors, each of which was not as large as the tip of the little finger, were found in the lower pharynx. There were no findings of acute asphyxia death. The cause of death was determined to be delayed asphyxia caused by the malignant tumors.

Adult↗

Analysis of inflammable substances to determine whether death has occurred before or after burning.

In two murder cases involving burning, both victims had been set on fire in the open air after being drenched with kerosene. In the first case, carbon monoxide hemoglobin (COHb) saturation was found to be 2.1% in the left heart blood and 0.8% in the right heart blood, a ratio of 2.6 for left to right heart blood. Paraffin hydrocarbons were also detected in the left heart blood. It was determined that the victim had been set on fire before death and that burning had been the cause of death. In the second case, the COHb saturation was 0.21% in the left heart blood and 0.24% in the right heart blood, giving a left-to-right ratio of 0.9. Paraffin hydrocarbons were detected in the hair sample, but not in the left heart blood. It was determined that the victim had been set on fire after death, and the cause of death was suspected to be asphyxia due to compression of the neck.

Adolescent↗

Determination of disulfoton and its metabolites in the body fluids of a Di-Syston intoxication case.

Disulfoton and its metabolites, two sulfoxides and two sulfones, in the body fluids of a patient who had ingested Di-Syston were analyzed by FPD-GC and GC/MS. After the chemicals in the extract (Fraction 1) obtained by Extrelut column extraction were analyzed, disulfoton and sulfoxides in Fraction 1 were oxidized into sulfones. The sulfones in the extract (Fraction 2) obtained by Extrelut column extraction were analyzed and the estimated concentrations of metabolite were calculated. The concentrations of disulfoton and the sum of the metabolites in the blood collected on admission were 0.093 nmol/g (25.4 ng/g) and 4.92 nmol/g (corresponding to 1.35 micrograms/g of disulfoton), respectively. These concentrations appear to indicate a severe level of disulfoton intoxication.

Aged↗