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L I Benowitz

Publications and source records attributed to L I Benowitz.

82 records · Page 5Linked to original sources
PubMed1983

Increased transport of 44,000- to 49,000-dalton acidic proteins during regeneration of the goldfish optic nerve: a two-dimensional gel analysis.

Proteins synthesized in goldfish retinal ganglion cells and rapidly transported to the terminals of regenerating optic nerves were analyzed by two-dimensional (2-D) gel electrophoresis. Among the rapidly transported components, the most dramatic change observed during regeneration was for a family of polypeptides having molecular weights between 44,000 and 49,000 (44-49K) and isoelectric points of 4.6 to 4.9. Studies using [35S]methionine as a metabolic precursor in the eye showed that these proteins are present in both membranous and soluble fractions of the optic tectum, particularly during early stages of regeneration. Contralateral visual pathways, left intact to serve as controls, showed only very low levels of the proteins. These labeling changes were quantified in double-isotope studies, in which proteins from intact and regenerating sides were differentially labeled with [3H]proline and [14C]proline, comigrated on 2-D gels, and then counted for 3H/14C ratios. The labeling change for the 44-49K acidic proteins relative to the intact state was found to be over 100-fold in some day 19 regeneration samples and about 30-fold on day 40. Silver-stained gels of a tectal membrane fraction also revealed increased levels of the 44-49K acidic proteins during regeneration, indicating that the observed synthetic changes are accompanied by a net accumulation of the proteins.

Animals↗
PubMed1982

Mood, vegetative disturbance, and dexamethasone suppression test after stroke.

Assessments of mood disturbance and "vegetative" (appetite or sleep) disturbance as well as a single-dose dexamethasone suppression test (DST) were carried out in 25 randomly selected stroke patients and in 13 nonstroke control patients hospitalized in a rehabilitation center. Prevalence rates of moderate-to-serve depression of mood and vegetative disturbance were significantly higher in stroke patients than controls (48% and 52% versus 0% and 8%, respectively), as was the prevalence of abnormal DST results (52% versus 8%). Abnormal DST results were associated with the occurrence of moderate to severe mood, appetite, and sleep disturbances among all patients. in 2 stroke patients, repeated DST results paralleled the clinical course. The DST may be useful as an adjunct to the diagnosis and in monitoring the progress of the common and potentially reversible mood and vegetative disturbances occurring after stroke.

Aged↗
PubMed1981

Specific changes in rapidly transported proteins during regeneration of the goldfish optic nerve.

Double labeling methods were used to identify changes in the complement of proteins synthesized in the retinal ganglion cells and transported down the optic nerve during the process of axonal regeneration. Eight to 62 days after goldfish underwent a unilateral optic nerve crush, one eye was labeled with [3H]-, the other with [14C]proline. Control and regenerating optic nerves were dissected out and homogenized together after 5 hr, a time which allowed us to examine selectively membrane-bound components which migrate in the rapid phase of axoplasmic transport. Proteins from the two sides were so-purified and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Analysis of the 3H and 14C incorporation patterns along the gels revealed a radical shift away from the normal labeling spectrum during regeneration, with selective changes in labeling at particular molecular weights varying over a 3-fold range. Eight days after crushing the optic nerve, the greatest increases in labeling were seen for material with apparent molecular weights of 24,000 to 27,000, 44,000, and 210,000 daltons. These peaks declined thereafter, and on days 29 to 39, the most prominent increases were at 110,000 to 140,000 daltons. These studies indicate a continuously changing pattern in the synthesis and/or degradation of proteins that are rapidly transported down the optic nerve during regeneration and point to molecular species potential significance in the establishment of the visual map upon the brain.

Animals↗
PubMed1977

Localization of a brain protein metabolically linked with behavioral plasticity in the goldfish.

Immunofluorescent methods were used to map the distribution of a soluble, 32,000 dalton brain protein, the synthesis of which increases when goldfish master a vestibulomotor task. The protein was found to be associated with a family of approximately 15,000 cells which vary in diameter from 8 to 15 micrometer and possess multiple processes. These cells are distributed near periventricular and external surfaces from the spinal cord up through the forebrain, but are most abundant in the broad ependymal zones of the optic tectum and vagal lobes. This localization pattern suggests that one of the major changes in brain protein metabolism associated with performance of the 'float-training' task in goldfish may reflect the activity of a non-neuronal population of brain cells.

Animals↗
PubMed1976

Organization of the tectofugal visual pathway in the pigeon: a retrograde transport study.

In birds, superficial laminae of the optic tectum receive a massive retinal input; the tectum in turn projects upon the nucleus rotundus thalami, which then sends its efferents to the ectostriatal core of the telencephalon. To examine the detailed organization of this principal ascending visual pathway, small injections of the marker horseradish peroxidase (HRP) were placed in various sites throughout the ectostriatum (E) or nucleus rotundus (Rt) in pigeons. Analysis of the resulting patterns of retrograde labeling indicates the tectofugal pathway to be comprised of at least five different channels. Cells which lie at various depths in the stratum griseum centrale (SGC) of the tectum project upon distinct subdivisions of nucleus rotundus. Anterior portions of Rt receive input from superficial-most cells in the SGC, while medial and more caudal portions of Rt are projected upon by deeper SGC neurons. A ventral subdivision of Rt was found to receive its primary input from two pretectal nuclei. Additional inputs to all portions of Rt arise from nucleus reticularis superior thalami. The various subdivisions of rotundus in turn project upon distinct portions of the ectostriatum. Thus, the segregation between the different input classes into Rt is largely retained at the telencephalic level. In contrast, the nucleus triangularis, a dorso-medial extension of Rt which receives its input from the deepest of all SGC neurons, sends its efferents to all parts of the ectostriatum.

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