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Biomedical subjects

S COHEN

Publications and source records attributed to S COHEN.

At least 91 records · Page 5Linked to original sources
PubMed1960

Immunocytochemical study of gamma globulin in liver in hepatitis and postnecrotic cirrhosis.

Gamma globulin was demonstrated by immunocytochemical fluorescence technique in many reticuloendothelial cells of the hepatic sinusoids and of the fibrous tracts in various forms of hepatitis and in postnecrotic cirrhosis. In other liver diseases and in normal livers, even in the presence of hypergammaglobulinemia, few if any gamma globulin-containing cells were found. In contrast, spleen and lymph nodes showed no difference between postnecrotic cirrhosis or hepatitis and other types of cirrhosis or non-hepatic hypergammaglobulinemias. The gamma globulin-containing cells in the liver are on cytologic grounds considered reticuloendothelial cells showing transition to plasma cells and exhibiting little or no phagocytosis of tissue breakdown products. These cells are assumed to form rather than engulf gamma globulin. The possibility that the gamma globulin formed represents antibody to liver cell breakdown products is discussed.

Hepatitis↗
PubMed1959

After-effects of repetitive activity in a nerve ending.

REPETITIVE MECHANICAL STIMULATION CAUSES DEPRESSION OF EXCITABILITY IN ISOLATED PACINIAN CORPUSCLES: the mechanical threshold of the sense organ for producing nerve impulses increases progressively with time of repetitive stimulation. The effect is completely reversible; it can be elicited with repetitive stimuli of less than threshold strength. Within certain limits, the depression increases as a function of strength and frequency of the repetitive stimuli.

Nerve Endings↗
PubMed1959

Post-tetanic potentiation and depression of generator potential in a single non-myelinated nerve ending.

Repetitive activity at the non-myelinated ending of Pacinian corpuscles leaves the following after-effects: (1) With certain parameters of repetitive mechanical stimulation of the ending a depression in generator potential is produced. The effect is fully reversible and has low energy requirements. The effect is a transient decrease in responsiveness of the receptor membrane which is unrelated to changes in resting membrane potential. It appears to reflect an inactivation process of the receptor membrane. Within certain limits, the depression increases as a function of strength, frequency, and train duration of repetitive stimuli. (2) With other, more critical parameters of repetitive stimulation a hyperpolarization of the ending and of the first intracorpuscular Ranvier node may be produced. This leads to respectively post-tetanic potentiation of generator potential and increase in nodal firing threshold. The balance of these after-effects determines the threshold for the production of nerve impulses by adequate (mechanical) stimulation of the sense organ. The after-effects of activity at the node can be elicited by dromic (mechanical) stimulation of the ending, as well as by antidromic (electric) stimulation of the axon; the after-effects at the ending can only be produced by dromic and not by antidromic stimulation.

Nerve Endings↗