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Biomedical subjects

J Greaves

Publications and source records attributed to J Greaves.

35 records · Page 2Linked to original sources
PubMed1984

Determination of polyols in serum by selected ion monitoring.

We used gas chromatography-chemical ionization mass spectrometry with selected ion monitoring of the (M-59)+ ions to determine polyols (as their peracetyl derivatives) in serum. The internal standard was 2-deoxygalactitol. Mean (and SD) polyol concentrations (mg/L) in 33 normal sera were: erythritol 0.45 (0.14), threitol 0.20 (0.06), adonitol 0.06 (0.02), arabinitol 0.37 (0.12), xylitol 0.05 (0.02), mannitol 0.41 (0.45), galactitol 0.15 (0.11), sorbitol 0.16 (0.11). Arabinitol determined in the same 33 normal sera by trimethylsilylation was 0.39 (0.13) mg/L. In 32 samples from cancer patients with normal creatinine, all polyol concentrations were in the normal range except for seven increased erythritol and one increased threitol concentrations. In all six patients with renal dysfunction we found increased erythritol and arabinitol, and increased threitol and mannitol in four of the six. Initial results showed that only arabinitol concentrations increased in invasive candidiasis.

Candidiasis↗
PubMed1983

Competent to care.

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Clinical Competence↗
PubMed1982

Quantification of homoharringtonine and harringtonine in serum by chemical ionization mass spectrometry.

Homoharringtonine and harringtonine are esters of cephalotaxine and are naturally occurring alkaloids in certain coniferous trees in China. These compounds have been shown to have activity against certain types of leukemia in cell cultures, experimental animals, and initial clinical trials in China, and will undergo Phase I trials in several institutions. A gas chromatographic mass spectrometric technique was developed for the quantification of both drugs in serum. One drug serves as internal standard for the other. The drugs are extracted from serum with dichloromethane and are quantified by monitoring the protonated molecular ions of the trimethylsilyl derivatives obtained by chemical ionization (methane). Masses monitored are: m/z = 690 for homoharringtonine and m/z = 676 for harringtonine. Detection limit: 10 ng ml-1 (20 nmol); reproducibility: 1.6-15.0% in the 0-200 ng ml-1 range. Serum levels of harringtonine reached 145 ng mg-1 upon intraperitoneal injection of 3 mg kg-1 in BDF-3 mice.

Alkaloids↗
PubMed1982

The balanced future.

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Operating Room Nursing↗
PubMed1981

Studies on the pharmacokinetics of primaquine.

A sensitive and specific assay for primaquine in plasma and urine using gas chromatography/mass spectrometry has been developed and used to study the plasma kinetics of primaquine. Preliminary studies on the effects of single and multiple oral doses have been carried out. In both cases the drug was completely, or almost completely, removed from the plasma in 24 h. The concentration of primaquine in the plasma usually reached a peak 1-2 hours after oral administration. The plasma elimination half-life was about 4 h. Less than 1% of the dose was detected in the urine collected over a 24-h period following drug ingestion. When Caucasian volunteers were given primaquine and chloroquine concurrently, some of them developed significant methaemoglobinaemia. Primaquine was not detectable in the plasma of any of the volunteers, 24 h after each daily dose.

Chloroquine↗
PubMed1980

Plasma kinetics and urinary excretion of primaquine in man.

1 The kinetics of primaquine have been studied in twenty volunteers after single and multiple dose regimes. 2 The kinetic parameters were similar in glucose-6-phosphate dehydrogenase (G6PD) normal Thais, G6PD deficient Thais and in Caucasians. 3 The Caucasian subjects showed about 1% of the dose was excreted in the urine. 4 The kinetic parameters obtained from multiple dose studies in Thais were very similar to those obtained from single dose studies in Thais.

Asian People↗
PubMed1979

A selected ion monitoring assay for primaquine in plasma and urine.

The antimalarial drug primaquine was analysed in plasma and urine by gas chromatography mass spectrometry, using a deuterated internal standard. After freeze-drying and extraction with trichloroethylene the sample plus internal standard was reacted with Tri Sil TBT (a 3:3:2 by volume mixture of trimethylsilylimidazole, N,O,-bis-(trimethylsilylacetamide and trimethylchlorosilane) and an aliquot injected into the gas chromatograph mass spectrometer. The gas chromatographic effluent was monitored at m/z 403 and m/z 406, the molecular ions of the bis-TMS ethers of primaquine and 6-trideuteromethoxy primaquine. Calibration curves were prepared from standards made up in plasma and urine. Data from the analysis of plasma and urine samples from a volunteer who ingested the equivalent of 45 mg primaquine are presented.

Adult↗
PubMed1978

Gas chromatography mass spectrometry studies on biologically important 8-aminoquinoline derivatives.

Several substituted 8-aminoquinolines related to known antimalarial drugs have been studied by gas chromatography mass spectrometry. 5,6-Dihydroxy-8-aminoquinoline, a possible metabolite of Primaquine, can be detected by single ion monitoring after conversion to a trimethylsilyl ether derivative. The mass spectra obtained in this study indicate that there are certain ions which are characteristic of the trimethylsilyl ethers of hydroxylated 8-aminoquinolines and 5,6-dimethoxy-8-aminoquinolines. These compounds should thus be amenable to analysis if they were produced during in vivo metabolism studies. Using selected ion monitoring the derivatized compounds can be detected at submicrogram levels.

Aminoquinolines↗