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18


Walter Riss, PhD, 1925-2015

Mufson, Elliott; Rubinson, Kalman; Scalia, Frank
PMID: 26360550
ISSN: 1421-9743
CID: 2036832

Septal vein symmetry: implications for endoscopic septum pellucidotomy

Roth, Jonathan; Olasunkanmi, Adelou; Rubinson, Kalman; Wisoff, Jeffrey H
BACKGROUND: Endosopic septum pellucidotomy is used for treating patients with unilateral and specific types of bilateral hydrocephalus. The ideal location for septostomy is controversial; however, an avascular region is preferred. OBJECTIVE: As the septal veins (SVs) are viewed only from one side, we studied the symmetry of the SVs in an attempt to define a safe area for septostomy. METHODS: Sixteen cadaver brains were dissected. The septum pellucidum was exposed bilaterally and divided into 3 regions. SVs of both sides were evaluated according to number, size, distribution, and location relative to common markers on both sides. RESULTS: Each side included 1 to 7 large veins (mean +/- standard deviation, 2.3 +/- 1.4), 0 to 3 small veins (2.05 +/- 1.73), and a total of 2 to 7 veins (4.35 +/- 1.53). Of the large veins, 88% were located in the anterior septal region (anterior to the foramen of Monro). Among the 10 brains that were extensively dissected, 90% had asymmetric SVs (either in the number of large veins or in the existence of any veins) in at least 1 of the septal regions, and 50% of brains had asymmetric SVs in the anterior region. CONCLUSION: Distribution of the SVs is asymmetric in most cases. We recommend septostomy be performed at the anterior area of the middle septal region, at the level of the foramen of Monro, mid-height between the corpus callosum and fornix. Careful evaluation of preoperative images and thorough coagulation at the septostomy site are essential to avoid injury to a contralateral large SV
PMID: 21099564
ISSN: 1524-4040
CID: 114843

Location along the muscle's length is a determinant of myofibril size

Davidowitz, J; Rubinson, K; Onejeme, A
In a previous study of myofibril size in 'Pale' (fast-twitch-glycolytic) fibers of rabbit extraocular muscle (EOM), it was found that individual long Pale fibers demonstrate a substantial increase in the size of myofibril profiles from their proximal to their distal halves (Davidowitz et al., 1996b). That finding raised the question of whether such proximal-to-distal increase of myofibril size in the Pale fibers is determined by: (1) longitudinal position within the individual muscle fibers themselves or (2) location along the length of the muscle as a whole? This question was tested in the present study by comparing the original group of long Pale fibers, which extend the full length of the muscle, with two groups of short Pale fibers, which are respectively confined to the proximal and distal halves of the muscle. It was found that (a) in the proximal half of the muscle, the short fibers and the adjacent portions of the long fibers have the same smaller size of myofibrils, and (b) in the distal half of the muscle, the short fibers and the adjacent portions of the long fibers have the same larger size of myofibrils. This finding indicates that the proximal-to-distal increase of myofibril-profile size in these EOM Pale fibers is determined by location along the length of the muscle as a whole, and is not related to longitudinal position within the individual fibers themselves
PMID: 11145017
ISSN: 0040-8166
CID: 122680

Cell growth patterns and lens geometry: a quantitative study from three-dimensional reconstructions

Hendrix, R W; Rubinson, K
The growth of the lens of the sea lamprey, Petromyzon marinus, was studied over the 5 years of larval development. Whole lenses (25) and Golgi-impregnated cells (393) were reconstructed with computer-assisted microscopy. Several cellular geometric parameters (length, width, curvature, surface, volume, shape) were correlated with the position of the cell's base on the lens capsular perimeter. Based on these correlations, the cells formed four groups that correspond to the central anterior, germinative, transitional and cortical fiber zones. A fifth zone, containing nuclear fiber cells, never stained. Lens growth is exponential during the 5 years. The anterior epithelium increases in size and in cell number by cell growth and division. The posterior mass increases in cell number by recruitment and increases in size by cell growth. A model is proposed to account for the size and shape of the lens based upon the coupling of anterior and posterior growth patterns. Four zonal boundaries are defined by changes in cell growth patterns. With growth, cells are subsumed into adjacent zones and zonal boundaries move away from the lens center. We find no support for the suggestion that cells migrate centrally
PMID: 18621335
ISSN: 0040-8166
CID: 122681

Myofibril size variation along the length of extraocular muscle in rabbit and rat. II: global layer

Davidowitz J; Rubinson K; Jacoby J; Onejeme A
Systematic variation of myofibril profile size was observed along the length of both singly innervated fibers (SIFs) and multiply innervated fibers (MIFs) of the global (inner) layer of extraocular muscle (EOM). These findings contrast with the assumption that global layer fibers of EOM are structurally uniform along their length. Muscle fibers were reconstructed in serial sections along the global layer of rabbit and rat EOM. Long fibers of the 'Pale' SIF (fast twitch glycolytic) and the MIF (tonic) populations were sampled by EM in both proximal and distal portions of the muscle. In rabbit, myofibril size of the Pale SIFs showed a proximal-to-distal increase of 28% whereas the MIFs showed a proximal-to-distal decrease of 10%. In rat, these two fiber populations showed analogous smaller changes. Measures of profile size included the mean intercept length and the mean shortest path from test points within the profile to the profile boundary. The possible effect of sarcomere length variation was controlled by normalizing the measures to a constant spacing of the myosin filament lattice
PMID: 8907728
ISSN: 0040-8166
CID: 8286

Myofibril size variation along the length of extraocular muscle in rabbit and rat. I: orbital layer

Davidowitz J; Rubinson K; Jacoby J; Philips G
It is generally assumed that a muscle fiber is structurally uniform along its length. That assumption is not consistent with the observed variation of myofibrillar profile size along the length of both singly innervated fibers (SIFs) and multiply innervated fibers (MIFs) in the orbital (outer) layer of extraocular muscle (EOM). Muscle fibers were reconstructed in serial sections along the orbital layer of rabbit and rat EOM. For both the SIFs and MIFs, myofibril profile size was smallest (narrowest) near the endplate. In the SIFs of rat, for example, the myofibril profiles were 28% wider at a distance of 1.5 mm from the endplate than at the endplate itself. Measures of profile size included the mean intercept length and the mean shortest path from test points within the profile to the profile boundary. The possible effect of sarcomere length variation was controlled by normalizing the myofibrillar profile size data to a constant spacing of the myosin filament lattice. This morphometric approach was also used to quantify the further increase of profile size that occurs in the end portions of the orbital MIFs where the myobrillar organization is typically ill-defined
PMID: 8907727
ISSN: 0040-8166
CID: 12647

The developing visual system and metamorphosis in the lamprey

Rubinson, K
Metamorphosis of the sea lamprey, Petromyzon marinus, is a true metamorphosis. The larval lamprey is a filter-feeder who dwells in the silt of freshwater streams and the adult is an active predator found in large lakes or the sea. The transformation usually occurs in the fifth or sixth year of life. Enlargement of the eye has been long accepted as a distinctive indication of metamorphosis in the sea lamprey, but it had been thought that this was because eye development in the larva was arrested after the formation of only the small central region. Recent studies indicate that all of the retina begins its development in the larva and that ganglion, amacrine, and horizontal cells differentiate in the peripheral retina of the larva. Retinal development is arrested during the premetamorphic period, to be resumed during metamorphosis. Metamorphic contributions include the differentiation of photoreceptor and bipolar cells. With the early appearance of ganglion cells, retinal pathways to the thalamus and tectum are established in larvae, as is a centripetal pathway. Tectal development spans the larval period but a spurt in tectal growth and differentiation is correlated with the completion of the retinal circuitry late in metamorphosis. The metamorphic changes in retina and tectum complete the functional development of the visual system and provide for the adult lamprey's predatory and reproductive behavior
PMID: 2258725
ISSN: 0022-3034
CID: 122682

Neural differentiation in the retina of the larval sea lamprey (Petromyzon marinus)

Rubinson K; Cain H
The peripheral retina of the sea lamprey develops in a 5-year-long process in which only certain neurons differentiate each year. The growth of cell layers, the differentiation of the neurons, and the morphology of their dendrites and axons were studied with normal, HRP, and Golgi preparations. Ganglion cells are differentiated in 3-year-old larvae, amacrine and horizontal cells in 4-year-old larvae, photoreceptor cells in stage I transformers, and bipolar cells in stage III transformers. Each new development is expressed as a radial gradient of differentiation. As a result of this protracted and stepped process, lamprey retinal neurons, particularly ganglion cells, differentiate in the absence of other cells to which they will ultimately be connected and may express their individual genetic programs more fully than in other vertebrate retinas. This could account for the unusual relationship of the ganglion cell, inner plexiform, and optic nerve layers and for the very high ratio of displaced to orthotopic ganglion cells
PMID: 2487105
ISSN: 0952-5238
CID: 10519

Efferent projections of the torus semicircularis to the medulla of the tadpole, Rana catesbeiana

Jacoby, J; Rubinson, K
Horseradish peroxidase injections into the medulla of tadpoles demonstrate, by back-filling, efferent neurons in the torus semicircularis which project to the ipsilateral superior olive. This projection, as well as one to the vicinity of the efferent neurons of the contralateral VIII and lateral line nerves, is confirmed by tracing anterograde transport following HRP injections into the torus semicircularis. These efferent neurons, located primarily in the principal nucleus of the torus within the terminal field of the projection from the superior olive, represent the only reported descending path to the superior olive and efferent nuclei in a non-mammalian vertebrate
PMID: 6607090
ISSN: 0006-8993
CID: 122683

The acoustic and lateral line nuclei are distinct in the premetamorphic frog, Rana catesbeiana

Jacoby, J; Rubinson, K
The transition from aquatic to terrestrial hearing in the frog occurs during metamorphosis and during the disappearance of the lateral line system. The coincidence in time of these two processes and morphological similarities between the acoustic and lateral line systems has led to the suggestion (Larsell, '34) that the lateral line nuclei are transformed into the acoustic nuclei. The relation between the acoustic and lateral line systems was investigated by studying the distribution of primary afferents, the dendritic patterns of the cells in the primary nuclei, and the development of the nuclei in the premetamorphic bullfrog, Rana catesbeiana. The posterior and anterior lateral line roots distribute to a neuropil located medial to the dorsal medullary nucleus. Horseradish peroxidase (HRP) injections into the contralateral tegmentum fill cells in the periventricular region whose dendrites ramify within the neuropil. These cells constitute the lateral line nuclei. The amphibian and basilar papillary roots of the acoustic system distribute to the more lateral nuclear region. The dendrites of these cells arborize within the nucleus and not in the lateral line neuropil. The dorsal medullary nucleus is, therefore, the acoustic nucleus (AcN). [3H]-thymidine labeling reveals that newly generated cells occupy the AcN within a few hours of their formation throughout the period when anatomical analysis shows the parallel growth and diminution of the lateral line neuropil and nuclei. This study indicates that the lateral line and acoustic systems are morphologically independent at the level of the primary afferents and primary nuclei throughout early development.
PMID: 6602814
ISSN: 0021-9967
CID: 163814