A physiologic model to describe bupivacaine uptake by and elimination from brain and heart was developed. Preliminary validation of the model was accomplished by comparing concentration data predicted by the model with those determined in rabbits. The model was modified to examine similarities and differences following intravenous and epidural administration of 150 mg of bupivacaine in humans. Simulations illustrated why rapid cardiovascular and central nervous system toxicity occurs following intravenous administration and is absent when an identical dose is administered epidurally. A slow continuous intravenous infusion of bupivacaine was simulated to examine the possibility that brain and heart concentrations would continue to accumulate reaching toxic concentrations in the absence of blood concentrations associated with bupivacaine toxicity.

Animals↗

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Superior hypogastric plexus block successfully treats severe penile pain after transurethral resection of the prostate.

BACKGROUND AND OBJECTIVES: Superior hypogastric plexus block has been used to treat cancer pain of the pelvis. METHODS: A patient with severe chronic nonmalignant penile pain after transurethral resection of the prostate underwent a single superior hypogastric plexus block with local anesthetic and steroid. The patient was also started on medications that treat neuropathic pain a few hours after the procedure was finished. RESULTS: The superior hypogastric plexus block resulted in complete pain relief immediately after the procedure. The pain relief continued at 1, 2, 4, and 8 months follow up. CONCLUSIONS: In this case of severe penile pain the superior hypogastric plexus block was useful diagnostically and therapeutically.

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PubMedDate not supplied

Immobilization antigens from Tetrahymena thermophila are glycosyl-phosphatidylinositol-linked proteins.

We have studied four strains of Tetrahymena thermophila, each of which expresses a different allele of the SerH gene and produces a distinctive surface protein of the immobilization antigen (i-antigen) class. Following exposure of the strains to [3H]ethanolamine or [3H]myristic acid, a protein corresponding in molecular mass to the characteristic i-antigen for that strain became highly labeled, as determined by mobility in sodium dodecylsulfate-polyacrylamide electrophoresis gels. Furthermore, antibodies raised to the i-antigens of the T. thermophila strains selectively immunoprecipitated radioactive proteins having molecular mass identical to that of the i-antigen characteristic for that particular strain. The lipid moieties labeled by [3H]myristate were not susceptible to hydrolysis by exogenous phosphatidylinositol-specific phospholipase C from bacteria. However, when protein extraction was carried out in the absence of phospholipase C inhibitors, radioactive fatty acids derived from [3H]myristate were rapidly cleaved from the putative i-antigens. On the basis of available data, it was concluded that T. thermophila i-antigens contain covalently-linked glycosyl-phosphatidylinositol anchors.

Animals↗

PubMedDate not supplied

MLTIDOSE: a multiple-dose simulation program for linear systems characterized by exponential functions.

MLTIDOSE is a multiple-dose simulation program for use on IBM PC (and compatible) computers. It assumes dose-independent disposition and absorption (i.e., a linear system) and simulates blood concentration-time profiles (over a range of times or at specific times) upon administration of any combination of intravascular (i.v.) (bolus and/or intermittent constant rate infusions) and extravascular (e.v.) doses of fixed or variable size, administered at fixed or variable intervals. Input requirements include pharmacokinetic parameters obtained following single-dose administration (entered from the keyboard or from a data file). Options for printing data to files (e.g., ASCII and DIF) for further use are also provided.

Computer Simulation↗

PubMedDate not supplied

Influence of age on intrinsic clearance of bupivacaine and its reduction by cimetidine in elderly male rats.

Explore the source record for details and available documents.

Aging↗

PubMedDate not supplied

Influence of cimetidine on bupivacaine disposition in rat and monkey.

Recent reports have appeared describing a cimetidine-induced alteration in either the input or disposition function for many drugs. The total clearance component of the disposition function is the primary perturbation. In the present investigation, the influence of cimetidine on bupivacaine disposition was studied, using in vitro and in vivo models. Since the extraction ratio for bupivacaine is low, total clearance follows the capacity-limited theory. Hence, the influence of cimetidine on the intrinsic clearance of bupivacaine was assessed using microsome and hepatocyte models. Results for both systems are in excellent agreement and indicate a noncompetitive inhibition. Additionally, the influence of cimetidine on the protein-binding profile of bupivacaine was determined. In the presence of cimetidine, the these findings was assessed in vivo in rhesus monkeys. co-administration of cimetidine resulted in an increase in the volume of distribution at steady state and no change in the total clearance of bupivacaine.

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