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J C Geer

Publications and source records attributed to J C Geer.

49 records · Page 3Linked to original sources
PubMed1969

Long-chain bases in the sphingolipids of atherosclerotic human aorta.

Long-chain bases were prepared from human aorta sphingomyelin by a combined enzymatic hydrolysis-alkaline hydrolysis procedure and these bases were isolated by thin-layer chromatography. Aldehydes, obtained from the long-chain bases by periodate oxidation, were converted to 1,3-dioxolane derivatives. Dioxolanes were identified and quantified by gas-liquid chromatography before and after catalytic hydrogenation, and before and after separation into saturated, monoene, and diene dioxolane fractions. The monoene dioxolanes were converted to aldehydes by reductive ozonolysis with dimethyl sulfide and these aldehydes were isolated and identified as dioxolane derivatives. The double bond positions in the major diene component were established by reductive ozonolysis and permanganate-periodate oxidation. Sphingenines in the cerebroside-sulfatide and sulfatide fractions of aorta were converted to aldehydes by the reductive ozonolysis of intact sphingolipids and these aldehydes were analyzed as the dioxolanes. Human aorta sphingomyelin contained significant amounts of 4-hexadecasphingenine, 4-heptadecasphingenine, sphinganine, 4-sphingenine, and 4,x14-sphingadienine. Small amounts of hexadecasphinganine, 4-tetradecasphingenine, a sphingadienine isomer, an unknown sphinganine, and two unknown diene long-chain bases were also found in sphingomyelin. The presence of a branched-chain 4-sphingenine was tentatively established and the possible presence of a sphingenine isomer was suggested. The major sphingenines were the same in the sphingomyelin, sulfatide, and cerebroside-sulfatide fractions of human aorta.

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PubMedDate not supplied

Computed tomography on invasive thymoma.

We report a case of invasive thymoma invading and occluding the superior vena cava in which the diagnosis was only made by the computed tomography (CT) study. Correlation of CT and autopsy findings of invasive thymoma were made in order to emphasize the usefulness of CT study in the evaluation of thymoma and its relationship with vascular structures.

Humans↗
PubMedDate not supplied

Arterial hypertension injures brain capillaries. Definition of the lesions. Possible pathogenesis.

Systemic hypertension (secondary to aortic coarctation) produces in monkeys, multifocal brain lesions where capillaries show increased diameter, endothelial degeneration and deposition of collagen and other substances in the basement membrane. In one animal, capillary changes were detected as early as 8 weeks after induction of hypertension. Similar capillary alterations were demonstrated in brain samples of hypertensive humans obtained at autopsy. We suggest that the above abnormalities may be the result of successive episodes of regional ischemia and/or hyperperfusion. Validation of these observations requires careful evaluation of additional human and animal brains.

Animals↗
PubMedDate not supplied

Innervation of brain intraparenchymal vessels in subhuman primates: ultrastructural observations.

Sympathetic innervation of intraparenchymal blood vessels in the basal ganglia was demonstrated by transmission electron microscopy in arteries, arterioles, and capillaries of the subhuman primate brain. Small arteries (40-120 micron) and some arterioles (12-40 micron) are innervated only at branching sites. However, arterioles occasionally may be innervated at points distal to their origin. Capillary innervation was very infrequently observed.

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