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Biomedical subjects

S Eksborg

Publications and source records attributed to S Eksborg.

120 records · Page 7Linked to original sources

Extraction of daunorubicin and doxorubicin and their hydroxyl metabolites: self-association in aqueous solution.

The extraction of daunorubicin and doxorubicin and their hydroxyl metabolites daunorubicinol and doxorubicinol was studied using chloroform-1-pentanol (9:1) as the organic phase. Because of differences in acid dissociation constants, the pH for optimum extraction varied from 8.0 to 8.6 for the different compounds. Self-association in the aqueous phase significantly influenced the distribution ratio. Constants for the formation of dimers and tetramers in aqueous solutions were about 10(4.5) and 10(12), respectively.

Chemical Phenomena↗

Determination of 8-methoxypsoralen in plasma by electron capture gas chromatography.

A method is given for the determination of 8-methoxypsoralen in human plasma at the low ng/ml level using gas chromatography with electron capture detection. 8-Methoxypsoralen was extracted from plasma with methylene chloride at pH 7.0. After addition of the internal standard, 8-butoxypsoralen, the psoralens were hydrolysed in sodium hydroxide and the aqueous phase was purified by extraction with methylene chloride and toluene. The aqueous phase was acidified and the re-lactonized psoralens were extracted with toluene and analysed. Some determinations of plasma levels of 8-methoxypsoralen after oral administration are presented.

Administration, Oral↗

Pharmacokinetic and metabolic studies of busulfan in rat plasma and brain.

Busulfan kinetics were studied in the rat plasma and brain after an I.P. dose of 14C-busulfan or busulfan (15 mg/kg). The distribution of busulfan to the brain was rapid and the ratio brain/plasma concentration was 0.74 during the time-course of busulfan. The elimination half-lives in plasma and brain were 3h for intact busulfan and 8h for the 14C-radioactivity. The radioactivity remaining in plasma and brain after 24h was mostly busulfan metabolites e.g. sulfolane, 3-hydroxysulfolane and tetrahydrothiophene-1-oxide as identified by gas chromatography-mass spectrometry. The protein binding to rat plasma was low (9.2 +/- 4.4%).

Animals↗

Sudden infant death syndrome: postmortem findings of nicotine and cotinine in pericardial fluid of infants in relation to morphological changes and position at death.

Parental smoking is considered to be an important risk factor for the sudden infant death syndrome (SIDS). We studied the concentrations of nicotine and cotinine in the pericardial fluid of SIDS and non-SIDS victims, with particular emphasis on the relationship to body position at the time of death and organ pathology. Pericardial fluid was collected during a forensic postmortem examination of 85 nonselected infants, under the age of 1 year, who died from SIDS (n = 67) and non-SIDS (n = 18) in the period from 1988 to 1994. There was no significant difference in the pericardial concentration of nicotine and cotinine between SIDS and non-SIDS victims. However, in contrast to non-SIDS victims, about 25% of the infants in the SIDS group had cotinine concentrations exceeding 30 ng/mL, indicating tobacco exposure prior to death. High concentrations of cotinine were found in infants with focal necrosis and inflammatory changes in the myocardium and the liver. Further, a relationship was found between high nicotine concentration and otitis media and also with death while cosleeping.

Body Fluids↗