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Biomedical subjects

A B Butler

Publications and source records attributed to A B Butler.

At least 37 records · Page 2Linked to original sources
PubMed1992

Retinal projections in the bowfin, Amia calva: cytoarchitectonic and experimental analysis.

The retinofugal projections in the bowfin, a non-teleost actinopterygian, were studied by autoradiographic and horseradish peroxidase methods, and the cytoarchitecture of retinorecipient regions of the diencephalon was analyzed with serially sectioned, Bodian stained material. Nuclei were identified in the thalamus, the periventricular portion of the posterior tuberculum, synencephalon, and pretectum which are homologous to like-named nuclei in teleosts and other non-teleost actinopterygian fishes. Of particular note, a posterior pretectal nucleus and, possibly, a homologue of nucleus corticalis were found to be present in the pretectum. These nuclei have previously been identified only in teleosts. The posterior pretectal nucleus is relatively small in the bowfin, and the distribution of a small, versus a large, posterior pretectal nucleus in Teleostei and Halecomorphi suggests that this nucleus was small plesiomorphically. The pattern of retinofugal projections in the bowfin is similar to that in other non-teleost actinopterygian fishes and in teleosts in most regards. Contralaterally, the retina projects to nuclei in the dorsal and ventral thalamus, superficial and central pretectum, dorsal and ventral accessory optic nuclei, and to the optic tectum. Additionally, there are sparse projections to the suprachiasmatic nucleus in the preoptic area, the periventricular nucleus of the posterior tuberculum, and the dorsal and ventral periventricular pretectal nuclei. Ipsilateral projections are sparse and are derived from fibers which do not decussate in the optic chiasm. Undecussated ipsilateral retinal projections, as present in the bowfin, are a widely distributed character in vertebrates and appear to be plesiomorphic for vertebrates.

Animals↗
PubMed1991

Retinofugal and retinopetal projections in the green sunfish, Lepomis cyanellus.

The retinofugal and retinopetal connections in the green sunfish were studied by autoradiographic and horseradish peroxidase methods. All retinofugal fibers decussate in the optic chiasm. Some fibers project to contralateral preoptic and hypothalamic nuclei while others recross to project to the comparable ipsilateral nuclei. Contralaterally, the medial optic tract projects to the periventricular thalamic and pretectal nuclei and, sparsely, to the rostral optic tectum. The dorsal optic tract projects to the parvocellular portion of the superficial pretectal nucleus, the central pretectal nucleus, nucleus corticalis, and the rostral portion of the optic tectum. The ventral optic tract primarily projects to the caudal portion of the optic tectum, giving off fibers in route to innervate various nuclei, including the parvocellular superficial pretectal nucleus and the dorsal and ventral accessory optic nuclei. The axial optic tract projects to the dorsal accessory optic nucleus, the central pretectal nucleus, and the caudal optic tectum. Retinal fibers reach the ipsilateral thalamus, pretectum and other sites via a redecussation through the posterior commissure. From outgroup analysis it is concluded that such redecussating fibers are an independently derived character within actinopterygians and are homoplasous to nondecussating ipsilateral retinal projections in other vertebrates. Neurons retrogradely labeled with horseradish peroxidase were found to form a rostrocaudal column from the olfactory bulb and nerve through the ventral telencephalon to caudal diencephalic levels along the medial aspect of the optic tract. It is possible that all these neurons consist of one population of migrated ganglion cells of the nervus terminalis.

Animals↗
PubMed1991

Comparative cytoarchitectonic analysis of some visual pretectal nuclei in teleosts.

The posterior pretectal nucleus, which in Osteoglossum receives second order visual input and projects to the inferior lobe of the hypothalamus, was identified and characterized in species from all major groups of non-neoteleost teleosts. The hypothesis that the posterior pretectal nucleus in these species is homologous to both the pars intermedius of the superficial pretectal nucleus and nucleus glomerulosus in acanthopterygians is supported by multiple similarities in relative position and cytoarchitecture. Nucleus corticalis, which receives retinal input and projects to the posterior pretectal nucleus (or to nucleus glomerulosus), was identified in species belonging to three of the four major teleost radiations. Both the posterior pretectal nucleus and nucleus corticalis are plesiomorphic for teleosts. The presence of glomeruli in the posterior pretectal nucleus and nucleus glomerulosus in esocids and acanthopterygians, respectively, and the presence of two nuclei, the pars intermedius and nucleus glomerulosus, in acanthopterygians, as opposed to one nucleus, the posterior pretectal nucleus, are apomorphies.

Animals↗
PubMed1991

Retinal projections in the freshwater butterfly fish, Pantodon buchholzi (Osteoglossoidei). I. Cytoarchitectonic analysis and primary visual pathways.

The freshwater butterfly fish, Pantodon buchholzi, is a member of the most primitive radiation of teleosts. The retinofugal projections were studied in this fish with autoradiographic and horseradish peroxidase (HRP) methods, and the cytoarchitecture of the retinorecipient regions in the diencephalon and pretectum was analyzed with Bodian-, cresylecht-violet- and acetylcholinesterase-reacted sections. The rostral diencephalon of Pantodon contains a large retinorecipient nucleus, not previously identified in any other fish, i.e. nucleus rostrolateralis. Other nuclei that are described correspond to those previously recognized in other species. The majority of retinorecipient nuclei are positive for acetylcholinesterase, particularly those in the pretectum, as has been found in other species of teleosts. Most of the retinofugal fibers decussate in the optic chiasm. Some fibers project via the axial optic tract to preoptic nuclei and a region in the rostral hypothalamus. Fibers leave the medial optic tract to terminate in nucleus rostrolateralis and in dorsal and ventral thalamic nuclei, accessory optic and tubercular nuclei, periventricular and central pretectal nuclei, and sparsely in the deep tectal fascicle and terminal field. Dorsal optic tract fibers project to the dorsal accessory optic nucleus, superficial and central pretectal nuclei, and superficial and deep tectal layers. Ventral optic tract fibers project to the superficial pretectum, accessory optic nuclei, posterior tuberculum, nucleus corticalis in the central pretectum, and superficial tectal layer. Fibers that remain in the ipsilateral optic tract project to most of the targets reached by contralaterally projecting fibers. A few fibers in the contralateral medial optic tract redecussate via the posterior commissure to reach the ipsilateral periventricular pretectum. No labeled retinopetal cells caudal to the olfactory bulb were identified in any of the HRP cases.

Acetylcholinesterase↗
PubMed1991

Retinal projections in the freshwater butterfly fish, Pantodon buchholzi (Osteoglossoidei). II. Differential projections of the dorsal and ventral hemiretinas.

Pantodon buchholzi, the freshwater butterfly fish, is a member of the Osteoglossomorpha, the most primitive of the four major teleost radiations. The projections of fibers originating in the dorsal and ventral hemiretinas in Pantodon, as determined with autoradiography, are reported here. Fibers originating in the ventral hemiretina reach their targets through the axial, medial and dorsal optic tracts. Fibers that originate in the dorsal hemiretina reach their points of termination by way of the axial, medial and ventral optic tracts. Projections of the various tracts to preoptic, thalamic, tubercular, pretectal and tectal regions, as described in the previous study of total retinal projections, were verified. The retinal projections to the preoptic, thalamic and tubercular nuclei do not map topographically. Ventral hemiretinal fibers are mapped, however, onto the dorsal part of the nucleus pretectalis superficialis pars parvocellularis, the rostral part of the dorsal accessory optic nucleus, the entire nucleus pretectalis periventricularis pars ventralis and the dorsomedial portion of the optic tectum. Ventral hemiretinal fibers also supply most if not all the retinal innervation to the central pretectal nucleus. In contrast, dorsal hemiretinal fibers are mapped onto the ventral part of nucleus pretectalis superficialis pars parvocellularis, the entire dorsal accessory optic nucleus and the ventrolateral portion of the optic tectum. The dorsal and ventral hemiretinal projections to the tectum about at a cytoarchitectonically recognizable point, indicating that no discontinuity is present in the retinal connectivity with the tectum. The pars parvocellularis of nucleus pretectalis superficialis is a simple, unfolded, and nonlaminar structure in Pantodon. This structure contrasts markedly with the more complex, folded structure of the nucleus in the majority of other examined teleosts. The orientation of the projections from the dorsal and ventral hemiretinas onto this nucleus in Pantodon is congruent with that seen in other fishes only after a schematic unfolding of the nucleus in these fishes.

Animals↗
PubMed1989

Quantification of the c-myc oncoprotein in human glioblastoma cells and tumor tissue.

The identification of a quantifiable oncoprotein marker in glial cells could lead to its use as an aid in the diagnosis, grading, and treatment of tumours of glial origin. In this study, monoclonal antibodies to the c-myc oncoprotein were used in conjunction with immunofluorescence microscopy, flow cytometry, and immunoblot analysis to quantitate and characterize the expression of this oncoprotein in neoplastic and benign cultured glial cells and brain-tumor tissue. Flow cytometric analysis revealed that the c-myc oncoprotein was highly expressed in neoplastic cell lines and in glioblastoma tumor specimens. In contrast, anti-c-myc oncoprotein staining was not present in a non-neoplastic glial cell line or in a benign brain tissue specimen. Immunoblot analysis revealed two distinct c-myc oncoprotein bands, having molecular weights of 64 and 75 kD. Densitometric determinations of the relative levels of the 64-kD protein were in good agreement with the determinations made by flow cytometry. Flow cytometry was also used to relate the quantity of the c-myc oncoprotein present in the cells to their cell cycle phase. In the malignant cultured cells, the protein underwent an approximate twofold increase as the cells progressed from G1/G0 to G2/M in the cell cycle. The present results suggest that the c-myc oncoprotein may prove to be a useful marker for the proliferation status and/or malignancy of glial cells.

Brain Neoplasms↗
PubMed1984

Telencephalic connections in lizards. I. Projections to cortex.

The afferent connections to five cortical regions in two distantly related species of lizards (Gekko gecko and Iguana iguana) were studied by means of retrograde transport of horseradish peroxidase conjugated to wheat germ agglutinin. Each of the five cortical regions is characterized by a specific pattern of projections from telencephalic, thalamic, hypothalamic, and brainstem regions. Subdivisions within the five cortical regions also receive different patterns of projections. The thalamo-cortical projections are as follows: The small-celled mediodorsal cortex receives a projection from nucleus dorsolateralis anterior pars magnocellularis. The large-celled mediodorsal cortex receives projections from nucleus dorsolateralis anterior pars parvicellularis and pars magnocellularis. The dorsal cortex receives a projection from nucleus dorsolateralis anterior pars parvicellularis. The lateral cortex receives a projection from nucleus dorsolateralis anterior pars magnocellularis. The pallial thickening receives projections from nucleus dorsomedialis and nucleus intercalatus. The latter nucleus receives a direct retinal projection. Thus, the pallial thickening is the recipient of a retino-thalamocortical projection. To date, comparisons of data from experimental studies have suggested that the cortical regions in lizards and turtles may be organized differently. However, the results of the present study suggest that the organization of cortical regions among reptiles is more similar than previously realized.

Afferent Pathways↗
PubMed1984

Telencephalic connections in lizards. II. Projections to anterior dorsal ventricular ridge.

Three distinct cytoarchitectonic regions were identified within the anterior dorsal ventricular ridge (ADVR) of two species of lizards, Gekko gecko and Iguana iguana. These regions have been named according to their general topographical positions: medial area, caudolateral area, and rostrolateral area. Injections of horseradish peroxidase throughout the ADVR demonstrated that each of the three areas of the ADVR receives projections from specific thalamic nuclei which are associated with specific sensory modalities. The medial area receives an auditory thalamic projection from nucleus medialis. The caudolateral area receives thalamic projections from nucleus medialis posterior and nucleus posterocentralis. The latter two nuclei were shown to receive projections from the spinal cord and, therefore, are presumed to be associated with body somatosensory information. The rostrolateral area receives a thalamic projection from nucleus rotundus, which receives visual information. In addition, the mesencephalic tegmentum and the thalamic nucleus dorsomedialis project to the entire ADVR. The latter projection is similar to the diffuse cortical projections of the intralaminar thalamic nuclei in mammals. These findings support previous suggestions that the ADVR is comparable to sensory regions of the mammalian neocortex.

Afferent Pathways↗
PubMed1984

Neonatally bulbectomized rats with new olfactory-neocortical connections are anosmic.

Rats with one olfactory bulb removed when neonates and the second bulb removed when adults were tested on tone-light discrimination and odor detection tasks. On the neonatally operated side reconstituted olfactory receptor cell axons penetrated the frontal neocortex or portions of the anterior olfactory nucleus, and formed glomerular-like structures. On the adult operated side there was extensive scar formation which prevented in-growing sensory axons from contacting the brain. All experimental animals acquired the tone-light discrimination but failed to show any evidence of odor detection. These results indicate that reconstituted olfactory projections which terminate in the frontal neocortex or anterior olfactory nucleus do not support olfaction.

Acoustic Stimulation↗
PubMed1984

Ineffectiveness of historical data in predicting measles susceptibility.

The Immunization Practices Advisory Committee ( ACIP ) has devised noninvasive, historical criteria for determining individuals who are susceptible to measles. These criteria, which involve proof of vaccination, are incorporated into school entrance regulations and are used to indicate people who require vaccination during outbreaks. In a recent measles epidemic in El Paso , TX, 120,000 records were screened using these criteria, and as a result 13,000 students were vaccinated. During this outbreak, 91 adolescents, who were susceptible to measles by ACIP criteria, were serologically tested for measles antibody. Although none of these students had documentation of vaccination, only 11.0% of them lacked measles hemagglutination-inhibiting (HAI) antibody at a titer of 5. Assuming a minimum cost for vaccine of +2.60 per dose, a conservative estimate of the cost to the El Paso Health Department for 20,000 doses of measles vaccine would be +52,000. If these data can be extrapolated to the total student population, then upwards of 85% of vaccinated students were already immune. Thus, +44,200 was spent unnecessarily. In addition, as the ACIP criteria did not select for measles susceptibility, an estimated 12,000 students in El Paso were not protected against measles. Other methods to determine measles susceptibility should be developed for optimal control of future outbreaks.

Adolescent↗
PubMed1983

Organization of eighth nerve afferent projections from individual endorgans of the inner ear in the teleost, Astronotus ocellatus.

Eighth nerve fibers from the saccule, utricle, lagena, and the anterior, horizontal, and posterior semicircular canals of a cichlid fish were traced to the octavolateralis region of the brainstem using HRP and degeneration methods. The anterior, magnocellular, descending, and posterior nuclei of the octavus column receive inputs from all endorgans, whereas the tangential nucleus receives projections only from the utricle and semicircular canals. The most rostral projections only from the utricle and semicircular canals. The most rostral projection from each endorgan is found in the eminentia granularis of the vestibulolateral lobe of the cerebellum. Sparse terminals are found in the medial reticular formation from the utricle adn semicircular canals, and utricular and saccular remain terminate in the vicinity of the lateral dendrite of the Mauthner cell. Utricular and semicircular canal projections consistently overlap centrally as do saccular and lagenar inputs. Afferent fibers from all endorgans end within relatively distinct regions throughout the octavus column of nuclei. Saccular and lagenar inputs lie dorsal to the semicircular canal terminations. Utricular endings are complex, however, in that they overlap dorsally with saccular and lagenar terminals and ventrally with the semicircular canal inputs. Cerebellar inputs are found only in the eminentia granularis of the vestibulolateral lobe, and the densest terminals are from the utricle and the semicircular canals; the sparsest are from the saccule. Previous studies in fish have indicated that generally the utricle and semicircular canals are concerned with he maintenance of static and dynamic equilibrium whereas the saccule and lagena are concerned with auditory reception. There is recent evidence, however, for multiple functions within individual endorgans. Our anatomical findings suggest that in Astronotus each otolithic endorgan carries more than one modality; that the semicircular canals are concerned solely with an equilibrium function; and that acoustic information is processed dorsally and vestibular information ventrally along the octavus column of nuclei. No single nucleus appears to be solely auditory in function and only the tangential nucleus, situated ventrally in the octavus column, appears to be solely vestibular.

Afferent Pathways↗
PubMed1983

Conjoined lumbosacral nerve roots. Diagnosis with metrizamide myelography.

The most common anomaly of the lumbosacral nerve roots consists of a composite root sleeve containing the roots for two spinal nerves. Before the advent of water-soluble myelography, this anomaly was rarely diagnosed except at operation. Metrizamide myelography readily demonstrates the anomaly because of improved filling of the root sleeves and greater definition of the nerve roots within the subarachnoid space. However, an underlying disk herniation may not be evident on the myelogram because of the unique anatomic configuration.

Adult↗
PubMed1982

An improved design of the pneumatic counter-pressure trousers.

Inflation of the circumferential pneumatic counter-pressure trousers was associated with the development of hemiparesis in a multiple trauma patient. We attribute this complication to the marked movement of the spinal cord that results from inflation of the circumferential abdominal compartment of the trousers. The design of the circumferential pneumatic counter-pressure trousers was recently modified so that the inflation portion of the abdominal compartment was restricted to the anterior portion of the abdomen. Inflation of the abdominal compartment of the modified trousers resulted in considerably less movement of the spine than with the trousers having the circumferential abdominal compartment.

Adult↗
PubMed1981

Efferent projections of the medial preoptic nucleus and medial hypothalamus in the pigeon.

The efferent projections of the medial preoptic nucleus (POM), anterior-medial hypothalamic area (AM), and the posteromedial hypothalamic nucleus (PMH) in the pigeon were traced by the autoradiographic technique. Similar and differential connections were noted from these regions. Projections from POM and AM-PMH were traced to nucleus septalis lateralis, nucleus dorsomedialis thalami, nucleus dorsolateralis anterior thalami (pars ventralis), posterior hypothalamic and medial mammillary areas, area ventralis tegmenti (Tsai), central gray of midbrain and nucleus intercollicularis and substantia grisea periventricularis of the midbrain. The density of silver grains in these regions differed with POM and AM-PMH injections. Other projections were observed exclusively from only one or two of the nuclear regions injected. Connections from POM and the rostral part of AM were seen to the median eminence, neurohypophysis, and the nucleus of anterior pallial commissure. Only cells of the anterior part of AM project fibers to nucleus septalis medialis. In the hypothalamus, projections from POM are concentrated in the periventricular region and in the preoptic-hypophyseal tract in the extreme lateral hypothalamus, while AM-PMH projections are heaviest in the medial hypothalamus and lateral preoptic area. A major difference in the connections of PMH from POM is the more substantial PMH projection to the midbrain. A prominent projection courses dorsolaterally and posteriorly from PMH toward nucleus ovoidalis and splits into two pathways: a lateral pathway which heavily innervates n. intercollicularis and the periventricular gray and a ventrolateral projection to the midbrain tegmentum. The projections described above provide anatomical substrates for neuroendocrine, autonomic, and behavioral functions.

Animals↗
PubMed1981

Nucleus laminaris of the torus semicircularis: projection to spinal cord in reptiles.

Neurons in nucleus laminaris of the torus semicircularis were retrogradely labeled following application of horseradish peroxidase (HRP) to the cervical spinal cord in two lizards (Gekko gecko and Iguana iguana) and a turtle (Pseudemys scripta). Different patterns of cell labeling were seen among the species studied and may be related to the distinctive differences in head and body movements seen in these animals during defensive, aggressive and social behaviors.

Animals↗