Biomedical subjects

F P Altman

Publications and source records attributed to F P Altman.

30 records · Page 2Linked to original sources

PubMed1976

Tetrazolium salts and formazans.

The history of the tetrazolium salts and formazans goes back 100 years, to when Friese (1875) reacted benzene diazonium nitrate with nitromethane, to produce a cherry-red "Neue Verbindung". This was the first formazan. 19 years later, Von Pechmann and Runge (1894) oxidised a formazan to produce the first tetrazolium salt. Many hundreds of tetrazolium salts and formazans were prepared in the following years, but only a handful have found applications in biological research. This article has attempted to describe the properties of these compounds, and to illustrate how the tetrazolium salt-formazan reaction has been exploited to serve an extremely wide variety of functions.

Animals↗

PubMed1975

The ultra-structural localization of enzyme activity in unfixed sections.

A technique is described for using conventional unfixed cryostat sections for localising enzyme activities in the electron microscope. The sections are incubated on the slide in the presence of a stabiliser, and then only fixed and embedded after the reaction is complete. Thin sections can then be cut of the reacted section, for electron microscopy. The present article shows that good ultra-structural morphology is retained during the freezing and cutting stages, and although some loss of detail occurs after the incubation, sub-cellular membranes are still intact, and membrane-associated reaction product can be clearly seen.

Animals↗

PubMed1975

The direct measurement of cytochrome P450 in unfixed tissue sections.

A method for the measurement of cytochrome P-450 in unfixed cryostat sections is described. The sections are incubated for 10 minutes at room temperature in a buffered solution containing polyvinyl alcohol and sodium dithionite. Two incubations are performed on serial sections, one in nitrogen and the other in carbon monoxide. Readings are taken on a Vickers M85 microdensitometer fitted with a high sensitivity photomultiplier amplifier system, the measurements being made on corresponding fields in the serial sections. Subtraction of the nitrogen values from the carbon monoxide values, after allowing for an absorption shift, gives the absolute spectrum of cytochrome P450. The subtraction corrects for the tissue content of other haem-containing proteins. The cytochrome P450 spectrum shows a sharp maximum at 450 nm, and two other minor components absorbing at 444 nm and 458 nm. The content of cytochrome P450 in animals fed with phenobarbitone was 2.4 times greater than in control animals.

Animals↗

PubMed1975