PubMed Health⌕ Search

Biomedical subjects

P Handler

Publications and source records attributed to P Handler.

At least 19 recordsLinked to original sources
PubMed1982

On carcinogenesis.

Explore the source record for details and available documents.

Carcinogens, Environmental↗
PubMed1981

Dynamic properties of cockroach cercal "threadlike" hair sensilla.

Input--output (I--O) relationships were studied in cercal "thread-hair" sensilla (THS) on Periplaneta americana L. by recording from individual axons of THS while displacing the corresponding hair with a galvanometric device. Sinusoidal analysis was attempted and pulse- and ramplike displacements were then tested. The effects of stimulus orientation were also investigated. THS were spontaneously active and purely phasic and did not respond to sustained displacements. With small sinusoidal displacements (less than 30 degrees) they behaved as a linear, second-order lead system sensitive to velocity. With larger amplitudes, however, they exhibited prominent nonlinear features with minimal consequences of displacements at the extremes. Responses to other waveforms indicated second-order response components. THS were directionally sensitive. Phasic behavior and the nonlinearities may be due to mechanical properties at the base of the hair. The spike-firing threshold may also contribute. Resting activity appears to be due to neuronal factors since it was not abolished by preventing hair movements. Transducer operations were simulated in a digital computer.

Animals↗
PubMed1970

Isolation of -L-glutaminyl 4-hydroxybenzene and -L-glutaminyl 3,4-benzoquinone: a natural sulfhydryl reagent, from sporulating gill tissue of the mushroom Agaricus bisporus.

Early in the development of spores, there appears in gill tissue of the mushroom Agaricus bisporus a red pigment that inhibits mitochondrial respiration. The inhibitor and its immediate precursor were isolated from the mushroom and identified as gamma-L-glutaminyl 3,4-benzoquinone (I) and gamma-L-glutaminyl 4-hydroxybenzene (II), respectively, neither of which had previously been described. II was synthesized chemically and the synthetic material was identical with isolated II in all regards. An enzyme that oxidizes II to I was isolated concurrently. I reacts unusually rapidly, completely, and at low concentration with the sulfhydryl groups of various mitochondrial enzymes, accounting for its originally observed properties. It may also prove of value as a general inhibitor of sulfhydryl-dependent enzymes.

Basidiomycota↗