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Biomedical subjects

M Yashiki

Publications and source records attributed to M Yashiki.

At least 19 recordsLinked to original sources
PubMed1999

Simple and sensitive analysis of nereistoxin and its metabolites in human serum using headspace solid-phase microextraction and gas chromatography-mass spectrometry.

A simple method for the analysis of nereistoxin and its metabolites in human serum using headspace solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) is developed. A vial containing a serum sample, 5M sodium hydroxide, and benzylacetone (internal standard) is heated to 70 degrees C, and an SPME fiber is exposed for 30 min in the headspace of the vial. The compounds extracted by the fiber are desorbed by exposing the fiber in the injection port of the GC-MS. The calibration curves show linearity in the range of 0.05-5.0 micrograms/mL for nereistoxin and N-methyl-N-(2-methylthio-1-methylthiomethyl)ethylamine, 0.01-5.0 micrograms/mL for S,S'-dimethyl dihydronereistoxin, and 0.5-10 micrograms/mL for 2-methylthio-1-methylthiomethylethylamine in serum. No interferences are found, and the analysis time is 50 min for one sample. In addition, this proposed method is applied to a patient who attempted suicide by ingesting Padan 4R, a herbicide. Padan 4R contains 4% cartap hydrochloride, which is an analogue of nereistoxin. Nereistoxin and its metabolites are detected in the serum samples collected from the patient during hospitalization. The concentration ranges of nereistoxin in the serum are 0.09-2.69 micrograms/mL.

Adult↗
PubMed1998

Determination of acrolein in human urine by headspace gas chromatography and mass spectrometry.

A rapid and sensitive headspace gas chromatographic and mass spectrometric (GC-MS) method was developed for the determination of acrolein in human urine. A 0.5-ml urine sample in a glass vial containing propionaldehyde as an internal standard was heated at 80 degrees C for 5 min. A 0.1-ml volume of headspace vapor was injected into a GC-MS instrument. Acrolein and propionaldehyde were coeluted at 3.1 min using a DB-1 capillary column, and well separated by selective ion monitoring (SIM) mode using ions m/z 56.05 and m/z 58.05. The interassay and intraassay coefficient of variation were 0.99% and 3.3%. The calibration curve demonstrated a good linearity throughout concentrations ranging from 1 to 1000 nM. However, due to a wide variation of acrolein evaporation rates from human urine, a calibration curve must be established for each urine specimen using a standard addition method and detection limit varied from 1 to 5 nM. The total analysis time for two samples from one urine specimen required about 15 min. Therefore, this method is convenient for the urgent monitoring of urinary acrolein in patients to whom alkylating agents are administered.

Acrolein↗
PubMed1998

Automated procedure for determination of barbiturates in serum using the combined system of PrepStation and gas chromatography-mass spectrometry.

A system of an automatic sample preparation procedure followed by on-line injection of the sample extract into a gas chromatograph-mass spectrometer (GC-MS) was developed for the simultaneous analysis of seven barbiturates in human serum. A sample clean-up was performed by a solid-phase extraction (SPE) on a C18 disposable cartridge. A SPE cartridge was preconditioned with methanol and 0.1 M phosphate buffer. After loading 1.5 ml of a diluted serum sample into the SPE cartridge, the cartridge was washed with 2.5 ml of methanol-water (1:9, v/v). Barbiturates were eluted with 1.0 ml of chloroform-isopropanol (3:1, v/v) from the cartridge. The eluate (1 microl) was injected into the GC-MS. The calibration curves, using an internal standard method, demonstrated a good linearity throughout the concentration range from 0.1 to 10 microg ml(-1) for all barbiturates extracted. The proposed method was applied to 27 clinical serum samples from three patients who were administrated secobarbital.

Adult↗
PubMed1998

On the influence of postmortem alcohol diffusion from the stomach contents to the heart blood.

Alcohol concentrations in the mixed left and right heart blood, urine and stomach contents of 186 cadavers were analyzed by gas chromatography in order to find the influence of postmortem diffusion of alcohol from the stomach contents to the heart blood. In 39 cases where blood alcohol concentrations (BACs) were less than 0.10 mg/g, alcohol in the stomach contents was suggested to be due to postmortem production, and the postmortem diffusion of alcohol from the stomach contents to the heart blood was less than 10%. In 147 where BACs were 0.10 mg/g and more, ratios of BAC to urine alcohol concentration (UAC) were 1.0 and more in 47 cases (32%), and less than 1.0 in 100 cases (68%). In 17 of these 147 cases, alcohol concentrations in stomach contents (SACs) were more than ten times as high as BACs. Where the highest ratio of SAC/BAC was 60.1, the BAC of 0.14 mg/g was suspected to be due to drinking. In the case where the highest SAC was 50.8 mg/g, the BAC of 5.18 mg/g, the highest in this study, seemed to be little affected by the diffusion. These results suggest that it is important to compare BAC, UAC and SAC to assess the influence of postmortem diffusion of alcohol from the stomach contents to the heart blood.

Alcoholism↗
PubMed1998

Simple analysis of local anaesthetics in human blood using headspace solid-phase microextraction and gas chromatography-mass spectrometry-electron impact ionization selected ion monitoring.

A simple method for analysis of five local anaesthetics in blood was developed using headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry-electron impact ionization selected ion monitoring (GC-MS-EI-SIM). Deuterated lidocaine (d10-lidocaine) was synthesized and used as a desirable internal standard (I.S.). A vial containing a blood sample, 5 M sodium hydroxide and d10-lidocaine (I.S.) was heated at 120 degrees C. The extraction fiber of the SPME system was exposed for 45 min in the headspace of the vial. The compounds adsorbed on the fiber were desorbed by exposing the fiber in the injection port of a GC-MS system. The calibration curves showed linearity in the range of 0.1-20 microg/g for lidocaine and mepivacaine, 0.5-20 microg/g for bupivacaine and 1-20 microg/g for prilocaine in blood. No interfering substances were found, and the time for analysis was 65 min for one sample. In addition, this proposed method was applied to a medico-legal case where the cause of death was suspected to be acute local anaesthetics poisoning. Mepivacaine was detected in the left and right heart blood samples of the victim at concentrations of 18.6 and 15.8 microg/g, respectively.

Anesthetics, Local↗
PubMed1998

Automated preparation and analysis of barbiturates in human urine using the combined system of PrepStation and gas chromatography-mass spectrometry.

A system for an automatic sample preparation procedure followed by on-line injection of the sample extract into a gas chromatography-mass spectrometry (GC-MS) system was developed for the simultaneous analysis of seven barbiturates in human urine. Sample clean-up was performed by a solid-phase extraction (SPE) on a C18 disposable cartridge. A SPE cartridge was preconditioned with methanol and 0.1 M phosphate buffer. After loading a 1.5 ml volume of a urine sample into the SPE cartridge, the cartridge was washed with 2.5 ml of methanol-water (1:9, v/v). Barbiturates were eluted with 1.0 ml of chloroform-isopropanol (3:1, v/v) from the cartridge. The eluate (1 microl) was injected into a GC-MS system. The calibration curves, using an internal standard method, demonstrated a good linearity throughout the concentration range from 0.02 to 10 microg/ml for all barbiturates extracted. The proposed method was applied to several clinical cases. The total analysis time for 20 samples was approximately 14 h.

Adult↗
PubMed1998

Simple analysis of tetracyclic antidepressants in blood using headspace-solid-phase microextraction and GC-MS.

A simple and sensitive method for analysis of three tetracyclic antidepressants, maprotiline, mianserin, and setiptiline, in human whole blood was developed using headspace-solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). A vial containing a blood sample, sodium hydroxide, and imipramine as an internal standard was heated at 120 degrees C. The extraction fiber of the SPME was exposed for 45 min in the headspace of the vial. The compounds absorbed on the fiber were desorbed by exposing the fiber in the injection port of a GC-MS. The calibration curves, using an internal standard method, demonstrated good linearity throughout the concentration range from 0.005 to 5.0 microg/g for mianserin and setiptiline and from 0.025 to 25 microg/g for maprotiline. No interferences were found, and the time for analysis was 60 min for one sample. In addition, this proposed method was applied to a medicolegal case in which the cause of death was suspected to be acute setiptiline poisoning. Setiptiline was detected in the left and right heart blood samples of the victim at concentrations of 1.77 and 0.78 microg/g, respectively.

Antidepressive Agents↗
PubMed1998

Interpretation of accelerants in blood of cadavers found in the wreckage after fire.

Accelerants in the blood of 73 cadavers found in wreckage after fire were analyzed by gas chromatography (GC) and a combination of gas chromatography-mass spectrometry (GC-MS) to decide whether accelerants containing petroleum components had been used and whether the cadavers had been exposed to fire before or after death. In 16 of 26 cases in which accelerants were used to start a fire before death, accelerants were detected in the blood. In 7 cases in which accelerants were used to start a fire, the victims were determined to have been exposed to the vapor of accelerants after death because no accelerants were detected in the blood, no soot was found in the airways, and carboxyhemoglobin (COHb) concentrations were not higher than those found in smokers. In 9 of 34 cases in which accelerants were suspected to have been used to start a fire before death, accelerants were detected in the blood. When soot is not detectable by the unaided eye in the airways of a victim found in debris of a fire in which the use of accelerants is suspected, or the COHb concentration in the blood is no higher than in a smoker, analysis of accelerants in the blood seems to be helpful in determining the cause of death and whether inflammable were used.

Adolescent↗
PubMed1998

[Difficulty of getting correct dental findings for a doctor of medicine: deciduous molars found in a 16-year-old female].

The first victim of four serial murders occurring in Hiroshima in 1996 was an unidentified young female when she was found. In the lower jaw, the left and right deciduous second molars were identified, and the left and right permanent second premolars were revealed to be congenitally defective by X-ray examination. Comparison of the dental findings and study model after death with those before death identified the victim as a 16-year old female.

Adolescent↗
PubMed1997

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↗
PubMed1997

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↗
PubMed1997

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↗
PubMed1997

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↗
PubMed1996

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↗
PubMed1996

[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↗
PubMed1995

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↗
PubMed1994

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↗