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Biomedical subjects

J J Freeman

Publications and source records attributed to J J Freeman.

At least 55 records · Page 3Linked to original sources
PubMed1980

Anticonvulsant properties of selected pyrrolo[2,3-d]pyrimidine-2,4-diones and intermediates.

A series of pyrrolo[2,3-d]pyrimidine-2,4-diones and intermediates was tested for anticonvulsant activity in mice. Eleven of the 15 compounds possessed anticonvulsant activity against pentylenetetrazol-induced convulsions. One compound afforded more anticonvulsant protection against pentylenetetrazol than did trimethadione (67 and 50%, respectively). A suspension of this compound was found to be as effective as a solution in producing anticonvulsant activity. The results suggest that the nitrile analogs were more potent compared to the carbamyl analog due to higher lipid solubility.

Animals↗
PubMed1980

In situ recording of rat heart contractility devoid of respiratory artifacts.

A device was constructed for obtaining the cardiac force of contraction in the rat in situ. The devices was constructed from heat-resistant glass tubing that was opened to form a concave channel. The channel was notched and cup-shaped at one end. The apparatus was positioned around the heart to isolate it from lung or diaphragmatic tissue movement. The procedure was rapid, simple, inexpensive and free of respiratory artifacts. The method was an improvement over the more common in vitro recording techniques, since the heart had an intact nerve and blood supply. The method allowed quantitation of changes in the force of contraction, blood pressure and heart rate following the administration of acetylcholine, epinephrine, potassium chloride and barium chloride.

Animals↗
PubMed1979

Selected cardiovascular and central properties of three lidocaine analogs.

Three analogs of lidocaine (benzyl carbamyl, benzyl nitrile and methyl nitrile) were synthesized and examined for cardiovascular and central activity. The benzyl carbamyl analog was more potent than lidocaine in lowering blood pressure but possessed only slight local anesthetic, antiarrhythmic and CNS-depressant activity. At 40 mg/kg the benzyl nitrile derivative was superior to lidocaine in protecting against chloroform-induced arrhythmias. The methyl nitrile analog was less active than the benzyl nitrile analog in most parameters examined. The benzyl nitrile derivative and lidocaine had similar potencies on blood pressure depression, local anesthetic activity and ability to protect against calcium chloride-induced arrhythmias. Unlike the benzyl carbamyl derivative both lidocaine and the benzyl nitrile compounds appear to depress the cardiovascular system via a common mechanism.

Anesthetics, Local↗
PubMed1979

Studies on the behavioral and biochemical effects of hemicholinium in vivo.

Hemicholinium (HC-3) causes a behavioral reactivity in rats which is correlated with the depletion of brain acetylcholine (ACh). The decrease in ACh levels and behavioral effects caused by HC-3 are correlated in a dose-dependent manner, maximal effects being achieved at an intraventricular (i.vt.) dose of 1 microgram. The HC-3 concentration in the brain 2 hr after i.vt. injection does not increase further with doses greater than 10 microgram. HC-3 (i.vt.) does not affect the uptake of choline (Ch) into subcellular fractions prepared from treated animals. ACh depletion in the brain areas studied closely parallels the HC-3 distribution. HC-3 pretreatment results in greater effects on newly synthesized than on stored ACh. Utilizing a concentration equal to that found in brain after an in vivo dose, HC-3 does not inhibit the uptake of Ch in synaptosomal preparations in which the neuronal membrane was disrupted with ether. The commonly accepted mechanism of action of HC-3, i.e., an inhibition of high affinity Ch uptake at the cholinergic nerve terminal, appears to provide a satisfactory explanation of its effects in vivo.

Acetylcholine↗
PubMed1977

Transfer functions for eye-level blood pressure during +Gz stress.

A description of the eye-level blood-pressure response to +Gz stress in relaxed humans was obtained as an empirical, ensemble-average, G-to-blood-pressure transfer function based on three subjects' responses to a total of 23 simulated aerial combat maneuvering runs on the USAFSAM human centrifuge. Three different analytic transfer functions were fitted to the empirical function for frequencies from 5 to 200 mHz, and predictive performance of the empirical and three analytic functions was examined. The double-zero, double-pole mathematical model most closely fit the empirical transfer function and displayed reasonable predictive ability.

Adult↗
PubMed1976

Effect of testosterone propionate on the ultrastructure of the preputial gland in the rat.

Testosterone propionate accelerates the maturation of acinar cells in the preputial gland of female rats. The weight of the preputial gland was increased significantly and the gland contained a large amount of secretory material. Various stages of maturation of acinar cells were observed. In an early stage, cells contained predominantly rough endoplasmic reticulum. In a second stage, lipid accumulated in association with focal areas of smooth endoplasmic reticulum. Membrane-bound dense bodies similar to lysosomes and secondary lysosomes predominated in a late stage. In the final stage, acini fused with a duct, thereby liberating the cells into the ductal lumen. Cell structure then became unrecognizable.

Animals↗
PubMed1975

The role of p-hydroxylation of amphetamine in its peripheral mode of action.

Desipramine completely abolished the blood pressure response to (+) amphetamine in the rat, whereas the tricyclic antidepressant iprindole did not reduce this response. Since both tricyclic drugs inhibit the aromatic hydroxylation of amphetamine, these studies do not support the hypothesis that hydroxylated metabolites of amphetamine, p-hydroxyamphetamine and p-hydroxynorephedrine are essential for the peripheral sympathomimetic effects of amphetamine.

Amphetamine↗
PubMed1975

The effect of hemicholinium on behavior and on brain acetylcholine and choline in the rat.

Behavior and whole brain acetylcholine and choline levels were studied in rats following intraventricular administration of hemicholinium-3. There was an 80% decrease in the content of acetylcholine after 2 hours. The depletion was associated with a decreased turnover of acetylcholine and aggressive behavior. The acetylcholine level did not return to control values until 72 hours after injection, when hemicholinium was still detectable as determined by fluorescence assay. Endogenous choline levels as determined by microwave fixation were 22.7 +/- 1.1 nmol g-1 and were unaffected by hemicholinium; however, hemicholinium caused a significant reduction in the postmortem increase in choline.

Acetylcholine↗