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Biomedical subjects

A S Kuperman

Publications and source records attributed to A S Kuperman.

16 recordsLinked to original sources
PubMed1976

The spirographic "kink". A sign of emphysema.

The significance of the "kink" occurring in the early portion of the forced expiratory spirogram of some patients with obstructed airflow was investigated in 153 patients with chronic obstructive pulmonary disease or asthma. The kink, which is presumably due to airway collapse, is facilitated by the presence of emphysema, which results in loss of elastic recoil, a positive pleural pressure, high bronchiolar resistance, and structural weakness in the walls of the major airways. A significant reduction of carbon-monoxide diffusing capacity was used as the indicator of the presence of significant anatomic emphysema. Eighty percent (39) of 49 patients with the spirographic kink had a low diffusing capacity, whereas only 16 of those without the kink had significantly impaired diffusion. Seventy percent (39) of the 56 patients who had emphysema by this criterion demonstrated a spirographic kink. This test is, therefore, offered as a simple, effective, and widely applicable screening procedure for detecting emphysema, with a low incidence of false-positive results.

Asthma↗
PubMed1970

Effects of sulphydryl inhibitors on frog sartorius muscle: p-chloromercuribenzenesulphonic acid.

1. Experiments were done on frog sartorius muscles to study the effects and mechanisms of action of the -SH inhibitors, p-chloromercuribenzoic acid (PCMB) and p-chloromercuribenzenesulphonic acid (PCMBS).2. Both organomercurials produce a depolarization of the surface membrane which is associated with a period of asynchronous twitching and followed by inexcitability.3. Only PCMB produces a unique fractionation of the electrically evoked twitch into an initial rapid and later slow phase.4. PCMB and PCMBS increase the rate of (45)Ca efflux from whole muscle. Ethylenediamine tetraacetic acid (EDTA, 5 mM) causes only limited antagonism of the enhancement of (45)Ca efflux produced by PCMB whereas it completely antagonizes this same effect of PCMBS. EDTA selectively removes superficial calcium without penetrating into the intracellular space.5. The results suggest that PCMB inhibits -SH groups in the terminal cisternae causing a fractionation of the twitch. PCMBS acts primarily at surface sites with limited access to the cisternae and sarcoplasmic reticulum.

Action Potentials↗
PubMed1970

Effects of sulphydryl inhibitors on frog sartorius muscle: N-ethylmaleimide.

1. The characteristic action of the -SH inhibitor, N-ethylmaleimide (NEM), is muscle rigour. The dose-response curve indicates a biphasic effect with maximum rigour tension produced by 1.0 mM NEM; beyond 1.0 mM there was an inverse relationship between dose and response.2. NEM produces a membrane depolarization unrelated to rigour development.3. NEM causes a sustained increase in (45)Ca efflux from whole muscle. Pretreatment of a muscle with ethylenediamine tetra-acetic acid (EDTA, 5 mM) to remove membrane calcium does not alter the NEM induced (45)Ca efflux.4. It is suggested that the primary site of NEM action is inhibition of calcium uptake by the sarcoplasmic reticulum thereby producing rigour. At concentrations above 1.0 mM, NEM may affect the myofilaments.

Action Potentials↗