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Biomedical subjects

Akira Namera

Publications and source records attributed to Akira Namera.

At least 19 recordsLinked to original sources
PubMed2004

Miniaturized sample preparation method for determination of amphetamines in urine.

A simple and miniaturized sample preparation method for determination of amphetamines in urine was developed using on-column derivatization and gas chromatography-mass spectrometry (GC-MS). Urine was directly applied to the extraction column that was pre-packed with Extrelut and sodium carbonate. Amphetamine (AP) and methamphetamine (MA) in urine were adsorbed on the surface of Extrelut. AP and MA were then converted to a free base and derivatized to N-propoxycarbonyl derivatives using propylchloroformate on the column. Pentadeuterated MA was used as an internal standard. The recoveries of AP and MA from urine were 100 and 102%, respectively. The calibration curves showed linearity in the range of 0.50-50 microg/mL for AP and MA in urine. When urine samples containing two different concentrations (0.50 and 5.0 microg/mL) of AP and MA were determined, the intra-day and inter-day coefficients of variation were 1.4-7.7%. This method was applied to 14 medico-legal cases of MA intoxication. The results were compared and a good agreement was obtained with a HPLC method.

Amphetamines↗
PubMed2004

Monitoring of urinary acrolein concentration in patients receiving cyclophosphamide and ifosphamide.

Acrolein, the metabolite of cyclophosphamide and ifosphamide, irritates mucous membranes and is considered pathogenetically important in hemorrhagic cystitis. Increasing fluid intake or administering sodium 2-mercaptoethanesulfonate (mesna), a thiol compound, can reduce the risk of this complication. We measured urinary acrolein concentrations using headspace-solid-phase microextraction gas chromatography and mass spectrometry (headspace-SPME-GC-MS) in 19 patients receiving cyclophosphamide and ifosphamide (36 occasions). Peak acrolein concentrations occurred at 1-12h (mean +/- S.D., 5.0+/-2.7) after starting therapy, ranging from 0.3 to 406.8 nM (39.7+/-76.7), with varying patterns over time. Maintaining high urine volume was important for preventing increases in urinary acrolein concentration, as urinary acrolein concentration tended to rise as urine volume decreased. Urinalysis detected occult blood in three cases, but the patients had no clinical symptoms of hemorrhagic cystitis. In clinical trials involving cyclophosphamide and ifosphamide, monitoring of urinary acrolein concentration could indicate when to take heightened preventive measures against hemorrhagic cystitis.

Acrolein↗
PubMed2004

[Development of salicylic acid detector tube].

A detector tube was successfully devised for the screening of salicylic acid in urine. It, named "salicylic acid detector tube", consists of glass tube in which silica gel coated with 5% (w/w) of ferric chloride is enclosed. A pipette rubber cap was attached to an end of the tube, and another end was inserted into urine sample. The sample was then introduced into the tube, the color of the reagent immediately turned purple under the condition of more than 50 microg/ml of salicylic acid in urine. This device was useful for the emergency screening of salicylic acid in acute poisoning cases with aspirin.

Acute Disease↗
PubMed2004

[On-site screening of toxic substances in clinical laboratory and poisoning information system].

An accurate screening system is required to treat acute poisoning patients in clinical toxicology. However, the medical center analysis of poisonous substances using machines is not sufficient. Moreover, the handling and maintenance of such machines are tedious and costly. To improve these problems and employ effective information, we have developed a simple detection method and constructed a support system using the Internet. Various support systems have been attempted for the training of analysts who can cope with a poisoning incident (accident) involving toxic substances. Our simple detection method for toxic substances in the medical center was developed without using expensive analysis apparati. As technical support for the analysts of medical laboratories, the following items were completed: 1) training for analysts, 2) research of analytical techniques in the medical centers (accuracy management), 3) creation of an analysis manual, 4) construction of on-line analysis manuals, 5) construction of the poisoning information system on the Internet, 6) construction of a system for requesting analysis of poisoning, 7) a quick-detection method for toxic substances and 8) examination of the insurance application.

Clinical Laboratory Information Systems↗
PubMed2004

[Acetaminophen].

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Acetaminophen↗
PubMed2004

[Amphetamines].

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Amphetamine-Related Disorders↗
PubMed2004

[Carbamates].

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Biomarkers↗
PubMed2004

[Development of the web system for analysis of toxic drugs and chemicals].

When poisoning or chemical incident occurs, it is important to examine and identify the causal substances rapidly to treat patients properly. In order to make it easily accessible for people who analyze samples, we developed the web system which provides the analytical methods of drugs and toxic compounds in biological samples such as blood and urine. The rapid analytical method using Test Kits and the instrumental analysis using GC/MS or HPLC are included. Photos of procedures and description on pitfalls during analysis are also included to make the system practically.

Databases, Factual↗
PubMed2003

Routine analysis of amphetamine and methamphetamine in biological materials by gas chromatography-mass spectrometry and on-column derivatization.

A simple determination method of amphetamine (AP) and methamphetamine (MA) in biological materials was developed using on-column derivatization and gas chromatography-mass spectrometry (GC-MS). AP and MA in biological materials were adsorbed on the surface of Extrelut and then extracted and derivatized simultaneously on the Extrelut column. AP and MA were derivatized to the N-propoxycarbonyl derivatives using propylchloroformate. Pentadeuterated MA was used as an internal standard. The recoveries of AP and MA from urine were 88.2 and 92.5%, and those from blood were 89.7 and 90.3%, respectively. The calibration curves showed linearity in the range of 12.5-2000 ng/ml (ng/g) for AP and MA in urine and blood, and 0.25-20 ng/mg in hair. When urine samples containing two different concentrations (200 and 1000 ng/ml) of AP and MA, blood samples containing two different concentrations (200 and 1000 ng/g) of AP and MA, hair samples containing two different concentrations (0.5 and 5.0 ng/mg) of AP and MA, the coefficients of variation of intra-day and inter-day were 0.68-3.60% in urine, 0.42-4.58% in blood, and 1.20-13.1% in hair. Furthermore, this proposed method was applied to a medico-legal case of MA intoxication.

Adult↗
PubMed2003

[A rapid determination kit for acetaminophen].

Acetaminophen (APAP: N-Acetyl-p-amino-phenol) is widely used as a nonprescription analgesic and antipyretic drug. Although APAP is usually well tolerated when used at the recommended dose, overdose has been associated with lethal hepatic necrosis. This toxicity has been correlated with elevated serum or plasma APAP levels and/or a halftime of elimination from these fluids exceeding four hours. Therefore a rapid method for determination of APAP is needed to treat a patient with an acute APAP overdose. We developed a simple and rapid method for determination of APAP and prepared a test kit. The test kit was based on the colorimetric method (indophenol method), but not including stinking reagents. The reaction mixture assumed pale blue to dark blue according to APAP concentrations and the determination range was 10-200 micrograms/mL with the naked eye. It took only 15 minutes for this test. In addition, the test kit could be adapted to APAP test in urine. We believe that the new APAP determination kit will be a useful tool for emergency diagnosis.

Acetaminophen↗