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Biomedical subjects

A B Butler

Publications and source records attributed to A B Butler.

At least 73 records · Page 4Linked to original sources
PubMed1976

Retinofugal pathways in the lingnose gar Lepisosteus osseus (linnaeus).

Retinal projections were studied with autoradiographic and silver methods in the gar, Lepisosteus osseus, one of the two surviving members of the holostean actinopterygians. Contralaterally, the retina projects to the preoptic nucleus of the hypothalamus, and, via the medial optic tract, to the dorsal thalamus, medial ventral thalamic nucleus, nucleus pretectalis profundus pars ventralis and pars dorsalis, and the medial portion of the deep layers of the central zone in the optic tectum. The dorsal optic tract projects to the lateral ventral thalamic nucleus, nucleus pretectalis centralis, and the superficial white and gray zone of the optic tectum. The ventral optic tract terminates in the nucleus of the ventral optic tract, the lateral and medial ventral thalamic nuclei, nucleus pretectalis superficialis, nucleus pretectalis centralis, nucleus pretectalis profundus pars ventralis, the basal optic nucleus, and the superficial white and gray zone of the optic tectum. Ipsilateral projections are to similar sites, except for an absence of inputs to the lateral ventral thalamic nucleus from the dorsal tract and to the nucleus pretectalis superficialis, nucleus pretectalis profundus pars ventralis, and the basal optic nucleus from the ventral tract. The presence of ipsilateral retinal projections in gars is compared to their presumed absence in teleosts, and comparisons of retinorecipient targets in gars are made with teleosts and with non-actinopterygian vertebrates.

Animals↗
PubMed1976

Pigmented ganglioneuroblastoma: relation of melanin and lipofuscin to schwannomas and other tumors of neural crest origin.

An unusual case of ganglioneuroblastoma containing melanin is presented. Electron microscopy revealed various stages of development of melanosomes in neoplastic cells of Schwann, the first direct demonstration in human material that these cells are malanogenic. The frequent occurrence of neuromelanin in autonomic ganglia and in ganglioneuromas is interpreted as the presence of altered lipofuscin. Review of ultrastructural and other observations indicates a relation between various pigmented tumors, the cell of Schwann, and other cells arising from the neural crest.

Adolescent↗
PubMed1976

'Sneeze syncope', basilar invagination and Arnold-Chiari type I malformation.

Syncope precipitated by sneezing in an adult male associated with an Arnold-Chiari type I malformation and basilar invagination presents a clinical problem in the differential diagnosis and pathological anatomy of Valsalva-related syncope. An abnormally acute clivoaxial angle, small foramen magnum, and type I Arnold-Chiari malformation appear to be a combination of features intolerant of Valsalva-induced changes in cerebral volume, brain-stem position, CSF fluid dynamics, or blood vessel relationships. Proposed mechanisms of pressure transmission to the area of intracranial pathology are discussed.

Adult↗
PubMed1976

Telencephalon of the lizard Gekko gecko (Linnaeus): some connections of the cortex and dorsal ventricular ridge.

Interhemispheric connections of the telencephalon in the lizard, Gekko, were studied with anterograde degeneration methods following lesions variously placed in the medial, dorsal, and lateral cortices and/or the dorsal ventricular ridge (D.V.R.). After lesions involving dorsal cortex, the medial wall, and the DVR, the majority of degenerated fibers decussate in the hippocampal commissure and terminate in the septum, medial wall, dorsal cortex, and the lateral edge of the DVR contralaterally. Lesions confined to dorsal cortex result in a similar pattern of degeneration, while lesions confined to the lateral wall result in degeneration in the contralateral lateral cortex, DVR and striatum, mainly via the anterior commissure. Some variation has been reported on the pattern of interhemispheric projections among reptiles studied to date; two possible interpretations of the data are that (1) dorsal cortex may be homologous as a field to parts of both neocortex and the hippocampal formation of mammals or (2) only the lateral part of dorsal cortex may be homologous to neocortex.

Animals↗
PubMed1975

A golgi study of the optic tectum of the tegu lizard, Tupinambis nigropunctatus.

The dendritic patterns of cells in the optic tectum of the tegu lizard, Tupinambis nigropunctatus, were analyzed with the Ramon-Moliner modification of the Golgi-Cox technique. Cell types were compared with those described by other authors in the tectum of other reptiles; particular comparisons of our results were made with the description of cell types in the chameleon (Ramń, 1896), as the latter is the most complete analysis in the literature. The periventricular gray layers 3 and 5 consist primarily of two cell types--piriform or pyramidal shaped cells and horizontal cells. Cells in the medial portion of the tectum, in an area coextensive with the bilateral spinal projection zone, possess dendrites that extend across the midline. The latter cells have either fusiform or pyramidal shaped somas. The central white zone, layer 6, contains fibers, large fusiform or pyramidal shaped cells, fusiform cells, and small horizontal cells. The central gray zone, layer 7, is composed predominately of fusiform cells which have dendrites extending to the superficial optic layers, large polygonal cells, and horizontal cells. The superficial gray and white layers, layers 8-13, contain polygonal, fusiform, stellate, and horizontal elements. Layer 14 is composed solely of afferent optic tract fibers. Several differences in the occurrence and distribution of cell types between the tegu and the other reptiles studied are noted. Additionally, the laminar distribution of retinal, tectotectal, telencephalic, and spinal projections in the tegutectum can be related to the distribution of cell types, and those cells which may be postsynaptic to specific inputs can be identified. The highly differentiated laminar structure of the reptilian optic tectum, both in regard to cell type and to afferent and efferent connections, may serve as a model for studying some functional properties of lamination common to cortical structures.

Animals↗