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Biomedical subjects

S S Sofer

Publications and source records attributed to S S Sofer.

7 recordsLinked to original sources
PubMed1990

In vitro synthesis of nitroxide free radicals by hog liver microsomes.

The in vitro biooxidation of 4-hydroxy-2,2,6,6-tetramethylpiperidine (TEMP), 4-hydroxy-2,2,4,4-tetramethyl-1,3-oxazolidine (TEMO) and diphenylamine (DPA) by hog liver microsomes to their respective nitroxide free radicals, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), 2,2,4,4-tetramethyl-1,3-oxazolidine-1-oxyl (TEMOO), and diphenylnitroxide (DPNO) has been investigated. For extending the life span of the liver microsomes, a calcium alginate immobilization procedure was used. The biooxidation rates of the above amines to their respective nitroxide metabolites were measured by means of oxygen uptake at 37 degrees C and pH 7.4. N-octylamine was found to be an activator in the biooxidation of the amines. The formation of the nitroxide radicals was identified by E.S.R. spectroscopy.

Alginates↗
PubMed1989

A mathematical simulation of the AIDS patient and extracorporeal detoxification.

A simple numerical simulation of AIDS patient detoxification by a hypothetical extracorporeal device for the removal of viruses, infected white cells, and syncytia has been designed. The mathematical model accounts for healthy blood white cells attacking and destroying the viruses, while at the same time the viruses attack and infect certain white cells. The infected white cells serve as a site for viral growth; eventually the cells lyse, releasing a large number of viruses into the blood stream. The healthy white cells and infected white cells combine to form syncytia, where the virus multiplies, and finally the syncytium ruptures releasing all the virus. This model can be used to predict concentrations over a specified period for the patient. This is a mathematical model to be used as a research and design tool only.

AIDS-Related Complex↗
PubMed1979

A model enzymic extracorporeal detoxification system.

Preliminary studies at the University of Oklahoma have incorporated the use of a continuous, seal-less blood centrifuge as an extracorporeal detoxification unit to aid in the removal of foreign chemicals from the blood. Detoxification is performed by immobilized enzymes in conjunction with a cofactor (NADPH) bound to a water-soluble macromolecule. A drug enters the device with the plasma and then passes across a semipermeable membrane which serves to retain the cofactor. At this point, a combination of the drug, the cofactor and the enzyme react to form the drug-oxide. The oxide then passes back through the membrane into the blood and back into the body. Concurrently, the macro-NADP+ is reduced by G-6-P and G-6-PD in the cofactor regeneration portion of the device. To facilitate detoxification, the centrifuge is employed to provide plasma rich in toxins, but void of potentially interfering blood components such as platelets and whole blood cells. These components tend to dilute the toxins or adhere to the interfacing membrane, decreasing the permeability of these toxins into the detoxification unit. It is felt that the centrifuge-detoxification combination will provide a potentially efficient hepatic assist device.

Aniline Compounds↗
PubMed1979

The removal of 14C labeled endotoxin by activated charcoal.

Endotoxin shock due to Gram-negative enteric bacteria is of major medical concern with an estimated 100,000 fatalities in the United States per year. An effective therapy for endotoxin shock, particularly in combination with significant liver damage, has not been available to date. Since activated charcoal is known as a universal sorbent, the use of activated charcoal in a hemoperfusion apparatus to remove endotoxin has interesting possibilities. Current assays for endotoxin are inadequate. The Limulus Amoebocyte Lysate (LAL) assay was found to give nonreproducible results within our range of requirements for accuracy. We, therefore, grew Salmonella typhimurium in 14C-labeled glucose to obtain 14C labeled endotoxin. Radiolabeled endotoxin was used to measure the rate of adsorption on activated charcoal. The rates of removal of endotoxin from normal saline, plasma, and whole blood will be presented in graphical form for use in design calculations. This work provides a foundation for encouraging in vivo hemoperfusion experimentation now underway at the University of Oklahoma and the Veteran's Administration Hospital in Oklahoma City.

Adsorption↗
PubMed1978

Non-conventional treatment of hepatic failures.

It is our intention to present a short review of various approaches to the non-conventional treatment of hepatic failures of the fulminant type. Our review is directed to the scientist, technologist, and clinician with a budding interest in the hepatic assist area. We shall discuss parabiosis, liver transplants, and various extracorporeal devices including hemoperfusion, hemodialysis, and enzymic detoxification systems. We feel that the present technological approaches to the treatment of hepatic failure are very primitive at this stage. Some of the recent advances are very encouraging, and it is our opinion that these approaches show great promise in the long term.

Animals↗
PubMedDate not supplied

Microsomal mixed-function amine oxidase. Oxidation products of piperazine-substituted phenothiazine drugs.

Oxidation products of fluphenazide, thioproperazine, and trifluoperazine obtained in reactions catalyzed by homogeneous preparations of the microsomal mixed-function amine oxidase have been isolated and identified. Approximately 0.5 g of metabolite of each piperazine-substituted phenothiazine drug was prepared in reactors containing, as catalyst, the purified oxidase covalently attached to glass beads. Nuclear magnetic resonance spectra of the isolated products indicated that with all three substrates the enzyme preferentially catalyzes N-oxidation of the piperazine nitrogen furthest from the phenothiazine nitrogen atom. The enzyme-catalyzed oxidation is quite specific and oxidation of the sulfur or nitrogen atoms in the phenothiazine ring could not be detected. Concentrations of piperazine-substituted phenothiazines required to half-saturate the amine oxidase were in the micromolar range and at pH 8.3 and 37 degrees C, all those tested were oxidized at approximately 2 mumol/min/mg of enzyme. Kinetic constants for the piperazine-substituted phenothiazines were very similar to those obtained with phenothiazines containing a dimethylaminopropyl sidechain.

Animals↗