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Biomedical subjects

L A Sternson

Publications and source records attributed to L A Sternson.

81 records · Page 5Linked to original sources
PubMedDate not supplied

Interaction of aromatic nitro compounds with reduced hepatic microsomal cytochrome P-450.

Aromatic nitro compounds interact with sodium dithionite-reduced microsomes to generate difference spectra characterized by a maximum at 400 nm and minima at 440 and 528 nm. Spectral binding constants of approximately 1 mM were calculated for ferrohemochromes in which nitrobenzene, p-nitrobenzoate, 2-nitrofluorene, and 2-nitronaphthalene served as ligands. Nitro binding affinity was increased approximately 3-fold by pretreatment of animals with phenobarbital (KS congruent to 0.3 mM). The interaction of nitro compounds with reduced microsomes from 3-methylcholanthrene-pretreated animals, however, failed to give discernable difference spectra. There is apparent mutual inhibition of binding of carbon monoxide, metyrapone, and nitro compounds with reduced cytochrome P-450, since addition of metyrapone or carbon monoxide to reference and sample cuvettes does not alter qualitative aspects of the nitro binding spectra, but only its magnitude. From the relative KS values, it is concluded that metyrapone and carbon monoxide interact with reduced cytochrome P-450 more tenaciously than nitro compounds.

Aerobiosis↗
PubMedDate not supplied

Biotransformation of azapetine to oxazapetine in rat and rabbit liver fractions.

The biotransformation of azapetine (I) to a lactam metabolite, oxazapetine (II), has been investigated in rat and rabbit hepatic subcellular fractions. In the presence of NADPH, II was produced from I in incubation mixtures containing 9000 g supernatant fraction or combined microsomes and cytosol, but not in mixtures containing microsomes or cytosol alone. Production of II was also observed when dehydrozapetine (III) was incubated with rabbit 9000 g supernatant fraction or cytosol. In washed rabbit microsomes II was not produced from III, but I was converted to III in the presence of NADPH. These results suggested that the biotransformation is initiated by microsomal enzymatic oxidation of I to III, followed by further oxidation of III to II by a soluble enzyme.

Adrenergic alpha-Antagonists↗
PubMedDate not supplied

Pharmacokinetics of non-protein-bound platinum species following administration of cis-dichlorodiammineplatinum(II).

The pharmacokinetics of non-protein-bound platinum species derived from cis-dichlorodiammineplatinum(II) (cis-platinum) was studied under a variety of dosing conditions. Following rapid infusions (15-minute) of cis-platinum at 100 mg/m2, the unbound drug declined in a biphasic mode with a mean terminal half-life of 48 minutes. The mean beta-phase half-life after a 6-hour infusion of the same dose of cis-platinum was 26 minutes. Urinary excretion of filterable platinum was substantially greater after a 6-hour infusion than after a 15-minute injection. Concomitant administration of mannitol appeared to result in higher peak plasma concentrations and decreased urinary excretion of unbound platinum species but did not alter the terminal half-life. Renal impairment was associated with extremely high plasma levels of filterable platinum but did not affect other pharmacokinetic parameters. Preliminary data on the distribution of cis-platinum to ascitic fluid are also presented.

Ascitic Fluid↗
PubMedDate not supplied

Plasma levels and urinary excretion of methyl-GAG following iv infusion in man.

The pharmacokinetics of methyl-GAG was studied after nephrectomy in five patients with renal cell carcinoma and in one patient with breast cancer. Following rapid infusion (30 minutes) of 700 mg/m2 of methyl-GAG, terminal half-life of 136-224 hours. Drug levels declined to 6%-20% of the initial plasma concentration in the first 24 hours. Approximately 40% of the dose was recovered in the urine after 2 weeks. Extensive extravascular distribution of methyl-GAG is suggested.

Antineoplastic Agents↗