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Biomedical subjects

W R Loewenstein

Publications and source records attributed to W R Loewenstein.

At least 73 records · Page 4Linked to original sources
PubMed1972

Development of a receptor on a foreign nerve fiber in a Pacinian corpuscle.

When the sensory fiber of a Pacinian corpuscle (in cat mesentery) is transected (at the inferior mesenteric nerve) transduction fails within 30 hours: the nerve ending produces no generator potentials in response to mechanical stimulation. Electrically elicited nerve impulse conduction continues for at least another 18 hours. A transducer mechanism develops on a regenerating nerve fiber when this fiber enters the denervated corpuscle. Such transducer development takes place on myelinated fibers from the inferior mesenteric nerve, which normally supplies corpuscles, as well as on myelinated hypogastric nerve fibers, which normally do not go to corpuscles, including fibers larger than the original corpuscle afferents.

Action Potentials↗
PubMed1969

Permeability of a cell membrane junction. Dependence on energy metabolism.

The ion permeability of the membrane junctions between Chironomus salivary gland cells is strongly depressed by treatments that are generally known to inhibit energy metabolism. These treatments include prolonged cooling at 6 degrees -8 degrees C, and exposure to dinitrophenol, cyanide, oligomycin, and N-ethylmaleimide. Intracellular injection of ATP appears to prevent depression of junctional permeability by dinitrophenol or to reverse it. Ouabain, azide, p-chloromercuriphenylsulfonic acid, reserpine, and acetazolamide fail to depress junctional permeability. Thus the ion permeability of the junctional membranes appears to depend on energy provided by oxidative phosphorylation. Possible energy-linked processes for maintaining junctional permeability are discussed, including processes involving transport of permeability-modifying species such as Ca(++).

Adenosine Triphosphate↗
PubMed1968

Structure of coupled and uncoupled cell junctions.

Cells of Chironomus salivary glands and Malpighian tubules have junctions of the "septate" kind. This is the only kind of junction discerned which is large enough to effect the existing degree of intercellular communication. The electron microscopic observations of the "septate" junction conform to a honeycomb structure, with 80-A-thick electron-opaque walls and 90-A-wide transparent cores, connecting the cellular surface membranes. A projection pattern of light and dark bands (the "septa") with a 150-A periodicity results when the electron beam is directed normal to any set of honeycomb walls. Treatment of the salivary gland cells with media, which interrupt cellular communication (without noticeable alteration of cellular adhesion) by reducing junctional membrane permeability or perijunctional insulation, produces no alterations in the junctional structure discernible in electron micrographs of glutaraldehyde-fixed cell material.

Animals↗
PubMed1968

Intercellular communication and tissue growth. 3. Thyroid cancer.

Intercellular communication was examined in normal and cancerous isolated thyroids with an intracellular electrical technique. The cells of normal thyroid (rat, mouse, hamster, man) communicate, within any given follicle, through permeable junctions. The cells of a wide variety of thyroid cancers (rat, hamster) do not communicate to any detectable degree and have resting membrane potentials lower than those of normal cells.

Animals↗