PubMed Health⌕ Search

Biomedical subjects

A P Gray

Publications and source records attributed to A P Gray.

At least 19 recordsLinked to original sources
PubMed1991

Inhibition of brain choline acetyltransferase in vivo: (E)-1-methyl-4-(1-naphthylvinyl)-1,2,3,6-tetrahydropyridine hydrochloride (B115), a depot form of a potent inhibitor.

The quaternary ammonium salt (E)-4-(1-naphthylvinyl)pyridine hydroxyethyl bromide (B111) and the tertiary amine salt (E)-1-methyl-4-(1-naphthylvinyl)-1,2,3,6-tetrahydropyridine hydrochloride (B115), both previously shown to protect against organophosphate (OP) toxicity, were examined in vivo for effects on rat brain choline acetyltransferase (CAT) activity and acetylcholine (ACh) levels. When administered iv, but not when given ip, B111 was able to inhibit brain CAT 29% and reduce brain ACh levels 25%, yet was unable to prevent soman-induced increases in ACh. B115, which may serve as a depot form of a quaternary ammonium analogue, was able to decrease CAT activity as much as 80% upon multiple ip administration. This CAT inhibitory potency was unprecedented for a tertiary amine salt of its structure. However, ACh levels were reduced by no more than 25% and B115 was ineffective in preventing soman- and sarin-induced increases in ACh. Since the degree of inhibition of CAT activity produced by B111 and B115 was not accompanied by a corresponding decrease in ACh levels, the protection afforded by these compounds against OP toxicity is most likely not related to CAT inhibition. B115 was also tested for its ability to affect cholinergic receptor binding. B115 was administered to rats ip, twice daily, at low doses throughout a 3-week period. Analysis of cortex tissue revealed a 45% increase in nicotinic receptor binding with no change in either total muscarinic receptor binding (M-1 and M-2) or high-affinity muscarinic receptor binding (M-2 alone).

Acetylcholine↗
PubMed1988

Cardiovascular effects of 1-methyl-4-(1-naphthylvinyl)piperidine hydrochloride.

1-Methyl-4-(1-naphthylvinyl)piperidine (B-120) produced a dose related decrease in blood pressure in cats. B-120 did not alter the cardiovascular response to acetylcholine or vagal stimulation. It did not affect the response of the nictitating membrane to both pre- and post-ganglionic stimulation. In isolated cortical synaptosomes, B-120 decreased calcium flux below basal levels. Thus, the blockade of calcium channels appeared to be related to the production of hypotension and may be the mechanism by which B-120 protected against organophosphate toxicity.

Animals↗
PubMed1988

Approaches to protection against nerve agent poisoning. (Naphthylvinyl)pyridine derivatives as potential antidotes.

Analogues of the potent inhibitor of choline acetyltransferase (CAT) (E)-4-(1-naphthylvinyl)pyridine methiodide were synthesized and evaluated for their ability to inhibit CAT and protect against nerve agent intoxication. Several compounds, notably (E)-1-(2-hydroxyethyl)-(1-naphthylvinyl)pyridinium bromide (3), (E)-1-methyl-4-(1-naphthylvinyl)-1,2,3,6-tetrahydropyridine hydrochloride (22), and (E)-1-methyl-4-(1-naphthylvinyl)piperidine hydrochloride (23), were found to afford significant protection against sarin in the mouse and against soman in the guinea pig. However, protection was apparently not related to CAT inhibition. Compound 23, our most effective compound in protecting against nerve agent, was without CAT inhibitory activity. Compound 22, which proved to be a potent CAT inhibitor, most likely owed this activity to being dehydrogenated back to the pyridinium quaternary salt by oxidative enzymes. Several of the (naphthylvinyl)pyridine quaternary salts, but not their tertiary amine analogues, were found to be effective in slowing the rate of aging of soman-inhibited acetylcholinesterase. Ability to slow the rate of aging was enhanced by introduction of methoxy substituents on the aryl moiety whereas the aging rate was actually accelerated by chloro substituents. To date, our most effective compound in slowing the rate of aging, (E)-4-[(4-methoxy-1-naphthyl)vinyl]pyridine methochloride (6), did not provide significant protection against soman in the mouse.

Acetylcholinesterase↗
PubMed1978

Steroid antifertility agents. Ionic complexes of basic derivatives for prolonged action.

Ethynylestradiol 3-dimethylaminopropionate (1), norethindrone 3-(O-dimethylaminopropyl)oxime (syn and anti isomers, 2a and 2b), and testosterone 3-(O-dimethylaminopropyl)oxime (3) have been prepared and converted to zinc and aluminum tannate complexes as potentially long-acting prodrug forms of the parent steroids. The basic derivatives and the complexes showed the appropriate hormonal activities although they were less active in acute tests than the respective parents. The complexes of 1 showed prolonged activities and, in particular, the zinc tannate showed a prolonged duration of antifertility activity in the rat on subcutaneous administration in an aluminum monostearate gel.

Animals↗
PubMed1977

Intracutaneous cornifying epithelioma ("keratoacanthoma") of dogs and keratoacanthoma of man.

The intracutaneous cornifying epithelioma ("keratoacanthoma") of dogs was compared with keratoacanthoma of man based on findings in the literature and in house studies. The two tumors differ at the following points: epithelium of origin, rate of growth, infiltration, spontaneous involution, breed predisposition (Norwegian Elkhound, generalized form), occurrence in dogs at a younger or middle age. The development of this tumor in dogs seems to be comparable with the development of so-called keratoacanthoma in Mastomys natalensis, which is virus-induced. Further investigations have been initiated to uncover the possible virus nature of the intracutaneous cornifying epthelioma (so-called keratoacanthoma) in dogs.

Animals↗
PubMed1976

Long-acting narcotic antagonist complexes.

We evaluated the ability of close to 100 organic acids to form water-soluble salts with methadone, cyclazocine, naloxone, naltrexone and, more recently, diprenorphine. About half the acids yielded insoluble salts. Polybasic acids affording insoluble salts were evaluated for their ability to form drug:acid:metal complexes with the polyvalent metal ions, Zn++, Al+++, Mg++ and Ca++. Optimum conditions for forming complexes have been developed and the consistency of their composition has been established. Salts were analyzed spectrophotometrically for drug content, and complexes were analyzed for drug and metal content. The in vitro degree of dissociation at equilibrium was measured for the preparations suspended in a simulated physiological buffer, pH 7.3. Preparations of the narcotic antagonist drugs showing relatively low degrees of dissociation in vitro, since it early appeared that a high degree of dissociation contraindicated a prolonged duration of pharmacological action, were evaluated in mice after intramuscular administration at several dose levels by the mouse tail-flick test for the potency and duration of their morphine antagonist activity. Our most promising preparations to date, showing the most prolonged durations of action without evidence of gross toxicity, are naltrexone zinc tannate and naltrexone aluminum tannate. These are undergoing detailed evaluation as potential clinical candidates. Thus far, the most useful of several dosage forms studied is a suspension in an aluminum monostearate gel.

Animals↗
PubMed1975

Long-acting narcotic antagonist complexes.

We evaluated the ability of close to 100 organic acids to form water-soluble salts with methadone, cyclazocine, naloxone, naltrexone and, more recently, diprenorphine. About half the acids yielded insoluble salts. Polybasic acids affording insoluble salts were evaluated for their ability to form drug:acid:metal complexes with the polyvalent metal ions, Zn++, Al+++, Mg++ and Ca++. Optimum conditions for forming complexes have been developed and the consistency of their composition has been established. Salts were analyzed spectrophotometrically for drug content, and complexes were analyzed for drug and metal content. The in vitro degree of dissociation at equilibrium was measured for the preparations suspended in a simulated physiological buffer, pH 7.3. Preparations of the narcotic antagonist drugs showing relatively low degrees of dissociation in vitro, since it early appeared that a high degree of dissociation contraindicated a prolonged duration of pharmacological action, were evaluated in mice after intramuscular administration at several dose levels by the mouse tail-flick test for the potency and duration of their morphine antagonist activity. Our most promising preparations to date, showing the most prolonged durations of action without evidence of gross toxicity, are naltrexone zinc tannate and naltrexone aluminum tannate. These are undergoing detailed evaluation as potential clinical candidates. Thus far, the most useful of several dosage forms studied is s suspension in an aluminum monostearate gel.

Aluminum↗
PubMedDate not supplied

Primary hemangiosarcoma of the iliopsoas muscle eliciting a peripheral neuropathy.

An eight-year-old, male castrated bullmastiff presented to the Kansas State University Veterinary Medical Teaching Hospital with left hind-limb paralysis. A mass was identified in the left paralumbar soft tissue adjacent to the fourth (L4) to sixth (L6) lumbar vertebrae by magnetic resonance imaging. The iliopsoas muscle contained the mass which was identified as a hemangiosarcoma on histopathological examination. Hemangiosarcoma is rarely reported as a primary tumor arising from muscle vascular endothelium.

Animals↗