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Biomedical subjects

A Reiner

Publications and source records attributed to A Reiner.

At least 253 records · Page 14Linked to original sources
PubMed1982

Immunoferritin binding to proteoglycan monomers. An electron microscopic study.

Antibody to native bovine nasal cartilage proteoglycan monomer was shown by enzyme-linked immunosorbent assay to react with the purified hyaluronic acid binding region of the monomer. Antibody was digested with pepsin to produce F(ab')2 and labeled with glutaraldehyde-activated ferritin. F(ab')2 and F(ab')2-ferritin were reduced and alkylated to render them monovalent (Fab'). Antibody Fab' binding to native proteoglycan monomer was studied by electron microscopy of monomer reacted with ferritin-labeled antibody Fab' spread in a cytochrome c film. Ferritin-labeled antibody Fab' bound primarily at one end of the proteoglycan monomer. This binding was partly inhibitable by unlabeled monovalent antibody Fab', demonstrating immunospecificity. The end of the monomer with bound ferritin sometimes appeared as the thin segment, previously observed to bind to hyaluronic acid. These observations indicate that the hyaluronic acid binding region is at only one end of each proteoglycan monomer and that ferritin-labeled antibody Fab' selectively attaches to this part of native proteoglycan monomers. This methodology should be useful for future structural studies of isolated proteoglycans.

Animals↗
PubMed1982

Basal ganglia pathways to the tectum: the afferent and efferent connections of the lateral spiriform nucleus of pigeon.

Previous studies have demonstrated that the lateral spiriform nucleus (SpL) of the avian pretectum receives a major input from the ipsilateral basal ganglia (Karten and Dubbeldam, '73) and projects to the ipsilateral optic tectum (Brecha et al., '76). The present study has further detailed the anatomical organization of the afferent and efferent connections of SpL, with particular reference to (1) the sources of afferent inputs to SpL, (2) the projection targets of SpL, and (3) the laminar termination pattern of the SpL projection to the tectum. The SpL was found to receive clear-cut major inputs from only three nuclei: (1) the ipsilateral paleostriatum primitivum (PP) of the basal ganglia (the avian homologue of the mammalian globus pallidus), (2) the ipsilateral anterior nucleus of the ansa lenticularis (ALa) of the diencephalon, and (3) the ipsilateral nucleus tegmentipedunculopontinus (TPc) of the mesencephalon. Both TPc and ALa have previously been noted themselves to receive major inputs from the ipsilateral PP (Karten and Dubbeldam, '73). Two other cell groups may give rise to a slight projection to the ipsilateral SpL: (1) the posterior nucleus of the ansa lenticularis (ALp) of the diencephalon and (2) the nucleus semilunaris (SLu) of the isthmic brainstem. The ALp also receives a major input from PP (Karten and Dubbeldam, '73). Two other cell groups may give rise to a slight projection to the ipsilateral SpL: (1) the posterior nucleus of the ansa lenticularis (ALp) of the diencephalon and (2) the nucleus semilunaris (SLu) of the isthmic brainstem. The ALp also receives a major input from PP (Karten and Dubbeldam, '73), while SLu receives a major tectal projection (Hunt and Kunzle, '76a). The ipsilateral tectum was found to be the only projection target of SpL. The present data suggest that the SpL projection to the tectum is restricted to layers 8-13, with layers 11-13 receiving the heaviest projection from SpL. Among layers 8-10, layer 9 receives the lightest projection from SpL. The present results indicate that SpL receives only a limited number of inputs, which in all likelihood relay largely basal ganglia input to SpL. Since SpL projects only to the tectum, the sole function of SpL apparently is the transmission of ipsilateral basal ganglia influences to the avian optic tectum. Tectal layers 8-15 have been previously found to represent the layers of origin of the descending pathways of the avian tectum to hindbrain motor and "premotor" cell groups (Reiner and Karten, '82). In view of the purported involvement of the basal ganglia in motor functions, the basal ganglia pathway to the ipsilateral tectum via SpL may represent a major route by which the avian basal ganglia exert influences over motor functions.

Afferent Pathways↗
PubMed1982

Enkephalin-mediated basal ganglia influences over the optic tectum: immunohistochemistry of the tectum and the lateral spiriform nucleus in pigeon.

By using immunohistochemical techniques with antisera directed against either leucine-enkephalin or methionine-enkephalin (generously supplied by K.-J. Chang), four distinct bands of fibers with enkephalinlike immunoreactivity were demonstrated in the pigeon tectum: (1) a thin band of thick fibers and tightly clustered bulbous swellings in layer 3, (2) a broader band of fibers with less tightly clustered bulbous swellings in layer 5, (3) a broad band of numerous obliquely and radially oriented fibers that spanned layers 8-13, and (4) a band of sinuous fibers in layer 15. In addition, numerous enkephalinergic cell bodies with radially ascending processes were seen in layers 8-10. Since the neurons of the avian lateral spiriform nucleus (SpL) of the pretectum are known to contain enkephalin (Davis et al., '80; De Lanerolle et al., '81) and project to the tectum (Brecha et al., '76; Reiner et al., '82), unilateral electrolytic lesions were made of SpL. In birds with unilateral lesions of SpL, layers 8-13 of the ipsilateral tectum were nearly devoid of enkephalinergic fibers, but no alterations were seen in layers 3, 5, and 15. Since no other neurons in the vicinity of SpL are enkephalinergic and project to the tectum, the loss of enkephalin-immunoreactive fibers in the ipsilateral tectal layers 8-13 is attributable to the destruction of SpL. Although the source of the enkephalinergic fibers in tectal layers 3, 5, and 15 is unclear, part of the enkephalin pattern in layers 3 and 5 may derive from the ascending processes of the enkephalinergic neurons of layer 8-10. The present results indicate that SpL has an enkephalinergic projection to layers 8-13 of the ipsilateral tectum. The avian SpL receives its major input from the ascending processes of the enkephalinergic neurons of layers 8-10, nuclei that themselves receive major basal ganglia inputs (Reiner et al., '82) and projects to the tectal layers 8-13 (Reiner et al., '82), the layers of origin of the major tectal efferent projections (Reiner and Karten, '82). The enkephalinergic fibers in layers 8-13 may, thus, have some influence upon the motor output functions of the avian tectum.

Animals↗
PubMed1982

Substance P-like immunoreactivity in the parietal eye visual system of the lizard Uta stansburiana.

We examined the parietal eye visual system of the iguanid lizard Uta stansburiana for the presence of substance P-like immunoreactivity by use of both immunofluorescence and peroxidase-antiperoxidase techniques. In the parietal eye no substance P-containing somata were found; however, its plexiform layer contained small (ca. 1 micron diam) immunoreactive fibers. These fibers apparently originate outside the parietal eye. Immunoreactive fibers also were found in the parietal nerve, the dorsal sac, and the leptomeninx of the pineal gland. No labeled somata were observed in any of these regions in either normal or colchicine treated animals. Previously we demonstrated that a system of centrifugal fibers to the parietal eye originates from neurons in the dorsal sac (Engbretson et al. 1981). The apparent absence of substance P-containing neurons in the dorsal sac suggests that the substance P-containing fibers in the parietal eye are not the previously observed centrifugal fibers. The source of the substance P-containing fibers in the parietal eye is unknown. The pars dorsolateralis of the left medial habenular nucleus receives a dense substance P-positive projection. No such projection was seen in the right habenula. Simultaneous visualization of the terminals of ganglion cells of the parietal eye (labeled with orthograde intraaxonally transported horseradish peroxidase) and substance P-like immunofluorescence showed that the locus of habenular immunoreactivity is distinct from the projection field of the parietal eye. Thus the substance P-positive terminals in the habenula do not originate in the parietal eye. Transection of the parietal nerve confirmed this conclusion.

Animals↗
PubMed1982

Age-related changes in the antigenicity of human articular cartilage proteoglycans.

Rabbits were immunized with adult or foetal human articular cartilage proteoglycans and cell-mediated and antibody immunity assessed in vitro. Cellular immunity to proteoglycans of different ages was measured by the stimulation of 3H-thymidine incorporation into cultured spleen cells. Antibodies to proteoglycans in the rabbit sera were detected with an enzyme-linked immunosorbent assay. The ability of adult and foetal proteoglycans to preabsorb antibody activity in this assay was compared. The results from both the cellular and antibody studies support the same conclusion, that adult proteoglycans express all foetal antigenic determinants and have additional determinants not seen on foetal proteoglycans. The reactivity of rabbit spleen cells to proteoglycans of different ages indicated that these determinants appear during maturation when the major changes in proteoglycan structure occur. The results did not appear to be due to differences in chondroitin sulphate content of the preparations, since the same observations were made with chondroitinase ABC-digested proteoglycans. The observations might be explained by other differences in glycosylation between the preparations or by postulating the synthesis during maturation of an additional proteoglycan species with a different core-protein. Such changes in the antigenicity of articular cartilage proteoglycans with age could account for the development of autoimmunity to proteoglycans in inflammatory joint diseases and may play a role in their pathogenesis.

Adolescent↗
PubMed1982

Substance P-containing neurons of the avian suprachiasmatic nucleus project directly to the nucleus of Edinger-Westphal.

Retrograde and anterograde pathway tracing techniques were used in the pigeon to study afferent visual input from the suprachiasmatic nucleus (SCN) of the hypothalamus to the nucleus of Edinger-Westphal (EW), the parasympathetic visceral efferent component of the oculomotor complex. Horseradish peroxidase injected into the EW retrogradely labeled numerous neurons in the contralateral SCN, a retinorecipient hypothalamic nucleus, as well as a few neurons in the ipsilateral SCN. Autoradiographic orthograde pathway tracing experiments confirmed that the SCN projects heavily upon the medial subdivision of the contralateral EW and lightly upon the medial subdivision of the ipsilateral EW. Some neurons of the SCN contain substance P and a substance P-positive plexus of fibers was seen in precisely that medial portion of the EW to which the SCN was found to project in the autoradiographic experiments. This substance P-positive fiber plexus in the medial EW was eliminated by bilateral electrolytic lesions of the SCN. These results show that the avian suprachiasmatic nucleus has a heavy contralateral and a much lighter ipsilateral projection to the medial subdivision of the EW and that this projection may be largely substance P positive. Previous studies have suggested that neurons of the medial EW specifically project to the neurons of the ciliary ganglion that control the choriocapillary blood flow of the eye. Since the SCN has been implicated in the control of circadian rhythms in vertebrates, the projection of the SCN to the EW may represent a pathway by which a circadian rhythmicity is imposed on choriocapillary blood flow. Alternatively or in addition, the SCN-EW pathway described in this paper may provide the central neural substrate for a homeostatic regulatory mechanism by which choriocapillary blood flow is controlled by the intensity of retinal illumination.

Animals↗
PubMed1982

Mammalian eyes and associated tissues contain molecules that are immunologically related to cartilage proteoglycan and link protein.

Monospecific antibodies to bovine nasal cartilage proteoglycan monomer and link protein were used to demonstrate that immunologically related molecules are present in the bovine eye and associated tissues. With immunofluorescence microscopy, reactions for both proteoglycan and link protein were observed in the sclera, the anterior uveal tract, and the endoneurium of the optic nerve of the central nervous system. Antibody to bovine nasal cartilage proteoglycan also reacted with some connective tissue sheaths of rectus muscle and the perineurium of the optic nerve of the central nervous system. Antibody to proteoglycan purified from rat brain cross-reacted with bovine nasal cartilage proteoglycan, indicating structural similarities between these proteoglycans. ELISA studies and crossed immunoelectrophoresis demonstrated that purified dermatan sulphate proteoglycans isolated from bovine sclera did not react with these antibodies but that the antibody to cartilage proteoglycan reacted with other molecules extracted from sclera. Two molecular species resembling bovine nasal link protein in size and reactivity with antibody were also demonstrated in scleral extracts: the larger molecule was more common. Antibody to link protein reacted with the media of arterial vessels demonstrating the localization of arterial link protein described earlier. Tissues that were unstained for either molecule included the connective tissue stroma of the iris, retina, vitreous body, cornea, and the remainder of the uveal tract. These observations clearly demonstrate that tissues other than cartilage contain molecules that are immunologically related to cartilage-derived proteoglycans and link proteins.

Animals↗
PubMed1982

An immunoelectron microscope study of the organization of proteoglycan monomer, link protein, and collagen in the matrix of articular cartilage.

Monospecific antibodies to bovine cartilage proteoglycan monomer (PG) and link protein (LP) have been used with immunoperoxidase electron microscopy to study the distribution and organization of these molecules in bovine articular cartilage. The following observations were made: (a) The interterritorial matrix of the deep zone contained discrete interfibrillar particulate staining for PG and LP. This particulate staining, which was linked by faint bands of staining (for PG) or filaments (for LP), was spaced at 75- to 80-nm intervals. On collagen fibrils PG was also detected as particulate staining spaced at regular intervals (72 nm), corresponding to the periodicity of collagen cross-banding. The interfibrillar PG staining was often linked to the fibrillar PG staining by the same bands or filaments. The latter were cleaved by a proteinase-free Streptomyces hyaluronidase with the removal of much of the interfibrillar lattice. Since this enzyme has a specificity for hyaluronic acid, the observations indicate that the lattice contains a backbone of hyaluronic acid (which appeared as banded or filamentous staining) to which is attached LP and PG, the latter collapsing when the tissue is fixed, reacted with antibodies, and prepared for electron microscopy. Thishyaluronic acid is anchored to collagen fibrils at regular intervals where PG is detected on collagen. PG and LP detected by antibody in the interterritorial zones are essentially fully extractible with 4 M guanidine hydrochloride. These observations indicated that interfibrillar PG and LP is aggregated with HA in this zone. (b) The remainder of the cartilage matrix had a completely different organization of PG and LP. There was no evidence of a similar latticework based on hyaluronic acid. Instead, smaller more closely packed particulate staining for PG was seen everywhere irregularly distributed over and close to collagen fibrils. LP was almost undetectable in the territorial matrix of the deep zone, as observed previously. In the middle and superficial zones, stronger semiparticulate staining for LP was distributed over collagen fibrils. (c) In the superficial zone, reaction product for PG was distributed evenly on collagen fibrils as diffuse staining and also irregularly as particulate staining. LP was observed as semiparticulate staining over collagen fibrils. The diffuse staining for PG remained after extraction with 4 M guanidine hydrochloride. (d) In pericellular matrix, most clearly identified in middle and deep zones, the nature and organization of reaction product for PG and LP were similar to those observed in the territorial matrix, except that LP and PG were more strongly stained and amorphous staining for both components was also observed. (e) This study demonstrates striking regional variations of ultrastructural organization of PG and LP in articular cartilage...

Animals↗
PubMed1981

Identification of core protein, an intermediate in proteoglycan biosynthesis in cultured chondrocytes from the Swarm rat chondrosarcoma.

After incubating cultured chondrocytes from the Swarm rat chondrosarcoma for 30 min with [3H]serine, a labeled macromolecule was found predominantly as Mr = approximately 370,000 species which was subsequently identified as a core protein precursor to cartilage proteoglycan from the following properties: (a) it was immunoprecipitated along with completed proteoglycan from cell extracts by an antiserum to the complex of hyaluronic acid-binding region, link protein, and hyaluronic acid. Its immunoprecipitation could be inhibited completely by the addition of purified hyaluronic acid-binding region to the extracts, indicating the presence of common antigenic determinants with this region of the proteoglycan core protein. (b) the core protein precursor was able to interact with the hyaluronic acid and link protein in proteoglycan aggregates added as carrier to extracts to form mixed aggregates of high buoyant density in associative CsCl density gradients. Labeled core protein precursor and link protein were subsequently isolated from the mixed aggregates from the top of dissociative CsCl density gradients. (c) radioactivity in core protein precursor after a 30-min pulse of [3H]serine disappeared after inhibiting further protein synthesis with cycloheximide concurrent with the appearance of label in completed proteoglycan molecules.

Animals↗
PubMed1981

Habenular asymmetry and the central connections of the parietal eye of the lizard.

Histochemical and autoradiographic analyses of the axonal transport of horseradish peroxidase and tritiated amino acids were employed to study the central connectivity of the lizard parietal eye. Somata and processes of centrifugal fibers to the parietal eye were localized in tissue of the dorsal sac and in the leptomeningeal sheath of the pineal gland. Analyses of series of transverse sections of the brain showed the left medial habenular nucleus to be subdivided into pars dorsolateralis and pars ventromedialis, and the right medial habenular nucleus not to be so subdivided. Centripetal fibers of parietal eye ganglion cells project to only the pars dorsolateralis of the left medial habenular nucleus and terminate there in two distinct fields. The asymmetry of the lizard habenula may be a specialization associated with the unilateral projection from the parietal eye.

Animals↗
PubMed1981

A projection of displaced ganglion cells and giant ganglion cells to the accessory optic nuclei in turtle.

The retinal projection to the accessory optic nuclei (AON) of turtles was found to arise from a distinctive set of giant ganglion cells whose dendrites ramify widely in outer portions of the inner plexiform layer. The majority (80%) of these cells had their perikaryon located in the ganglion cell layer, though displaced ganglion cells (DGCs) were also observed. In contrast, the retinal projection to the avian AON has been reported to arise exclusively from DGCs.

Animals↗