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Biomedical subjects

R Spector

Publications and source records attributed to R Spector.

At least 199 records · Page 11Linked to original sources
PubMed1974

Inhibition of penicillin transport from the cerebrospinal fluid after intracisternal inoculation of bacteria.

The effect of intracisternal inoculation of bacteria on the choroid plexus system, which transports penicillin from cerebrospinal fluid (CSF) to blood, was studied in vitro and in vivo. Meningeal and choroid plexus inflammations as well as CSF pleocytosis were induced in rabbits with intracisternal inoculations of Hemophilus influenzae or Staphylococcus aureus. At various times after bacterial inoculation, the choroid plexuses of the inoculated rabbits were removed and incubated in artificial CSF containing [(14)C]penicillin. The ability of the choroid plexuses to accumulate pencillin in vitro was measured and was found to be depressed as compared with controls. This depression of choroid plexus uptake reversed with resolution of the inflammatory process. In vivo on the day after intracisternal inoculation of Hemophilus influenzae, a decrease in the disappearance of penicillin relative to inulin in the inoculated rabbits (as compared to the controls) was observed when [(14)C]penicillin and [(3)H]inulin were injected intraventricularly and cisternal CSF was sampled 2 h later. This decrease could not be explained by penicillin binding to the CSF exudate. However, the choroid plexus transport system for penicillin was only partially depressed in those inoculated rabbits with bacterially induced inflammation, since in vitro the choroid plexuses could still accumulate penicillin and in vivo CSF penicillin levels could be further increased with probenecid pretreatment. These results suggest that CSF penicillin levels are increased in this model due to three factors: a depression of active efflux of penicillin from the CSF, an increase in permeability to penicillin of inflamed meninges, and, less significantly, by CSF binding of penicillin.

Animals↗
PubMedDate not supplied

Racial background and lidocaine pharmacokinetics.

The pharmacokinetics of lidocaine were investigated in 17 healthy young adult volunteers seven Caucasians, five Orientals, and five Blacks). With the assumption of a one-compartment open model and linear pharmacokinetics, analysis of the data determined that there were no significant differences in the volume of distribution, clearance, elimination half-life, and serum protein binding of lidocaine among these racial groups. Our finding that lidocaine clearance and protein binding are not significantly different in young adult Caucasians and Orientals is consistent with our previous hypothesis that drugs metabolized in the body by N-dealkylation (lidocaine and diphenhydramine) area cleared at similar rates in young adult Caucasians and Orientals when protein binding is taken into account.

Adult↗