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J Sawyer

Publications and source records attributed to J Sawyer.

71 records · Page 4Linked to original sources
PubMed1978

Studies on the distribution of phenylethanolamine N-methyltransferase and epinephrine in the rat.

Using two independent criteria, we have found the enzyme phenylethanolamine N-methyltransferase (PNMT) to be present in the adrenals, lungs, brain stem, spleen, heart and skeletal muscle of the rat. The lungs contained more activity than the brain stem or any other extra-adrenal organ. PNMT was not detectable, however, in the kidneys, stomach, liver and plasma. Trace amounts of epinephrine were found in brain stem, lung and heart; norepinephrine, however, was the predominant catecholamine in these tissues. Substantial quantities of epinephrine were found in the adrenal and plasma of decapitated animals, but the latter were essentially eliminated by adrenal demedullation. Our data indicate that although the adrenal is the principal tissue source of epinephrine and PNMT in the rat, small amounts of both substances are present in several body organs.

Adrenal Medulla↗
PubMed1977

Studies on the characterization and inhibition of rat brain phenylethanolamine N-methyltransferase.

The existence of phenylethanolamine N-methyltransferase (PNMT) activity in the rat brain and spinal cord was confirmed using both substrate specificity and selective inhibitors of the adrenal enzyme as biochemical tools. The enzyme was not generally localized throughout the central nervous system but was found primarily in the brain stem and spinal cord with lesser amounts occurring in the midbrain. No significant PNMT activity was found in markedly inhibited both in vitro and in vivo by low concentrations (doses) of SK&F 64139, a potent inhibitor of the adrenal enzyme.

Adrenal Glands↗
PubMedDate not supplied

Congenital aneurysmal hemorrhage and astrocytoma in an infant.

The authors present the unusual case of an infant who presented at 4 weeks of age with a spontaneous intracerebral hemorrhage due to rupture of a congenital left middle cerebral artery aneurysm. He recovered only to present at 4 months of age with a right frontoparietal desmoplastic cerebral astrocytoma of infancy. The association of brain tumor and aneurysm is discussed, as are the cytogenetic findings associated with this rare form of benign astrocytoma.

Astrocytoma↗
PubMedDate not supplied

To biopsy or not to biopsy in suspected herpes simplex encephalitis: a quantitative analysis.

The authors performed a decision analysis to determine whether a patient suspected to have herpes simplex encephalitis (HSE) should undergo a brain biopsy or be treated empirically with medical therapy. In most cases, empiric treatment with acyclovir would be slightly favored; brain biopsy was not essential in management. However, brain biopsy was found useful for patients who had low CSF glucose at the time of initial lumbar puncture; such patients may have a very high risk to have other treatable conditions such as tuberculosis, brain abscess, toxoplasmosis, or cryptococcosis. The results of the analysis suggest that even with the advent of safe antiviral drug therapy such as acyclovir, brain biopsy is useful in a well-defined subset of patients with possible HSE. The rationale, however, is not to confirm HSE but rather to detect other treatable conditions.

Acyclovir↗