One-stage key pinch and release with thumb carpal-metacarpal fusion in tetraplegia.

One-stage key pinch and release with carpal-metacarpal fusion, extensor pollicis longus tenodesis, and motor transfer to flexor pollicis longus were analyzed for functional results in tetraplegic patients. Eighteen patients (21 hands)--all with International Classification OCu:4 hand function or worse--were studied. Average follow-up was 42 months. All patients experienced significant increase in functional ability and thought the surgery was highly beneficial. Average pinch strength was 3.3 kg, whereas it had been nonmeasurable preoperatively. Both activities of daily living and pinch strength correlated with tetraplegic functional level. The patients with higher preoperative functional level had better postoperative activities of daily living scores and pinch strength. Sixteen hands had solid fusions, and patients with fibrous nonunions showed no decrease in pinch strength, pain, or functional limitations when compared with the patients who had solid fusions. Six hands showed degenerative changes at one or more adjacent joints, but this was not related to results.

Cerebellin is a postsynaptic neuropeptide.

Cerebellin is a hexadecapeptide that has been biochemically characterized and localized to cerebellar Purkinje cells and certain neurons of the dorsal cochlear nucleus (DCoN) of rat. Among rabbit antisera produced to synthetic cerebellins, one (C1) gave specific immunostaining of the Purkinje neuronal cell body, initial axon segment, and main stem dendrites, while another (R2) reacted with peripheral dendritic structures. This complementarity of staining was also present during cerebellar development. By electron microscopy, the immunoreaction product was localized to polyribosomal domains with antiserum C1 and to dendritic spines with antiserum R2, in both cerebellar cortex and DCoN. In the spine, the structure most strongly stained was the postsynaptic density, but some reaction product was adsorbed to the plasma membrane, the spine apparatus, and the granulofibrillar cytoplasmic component. Antiserum R2 also stained lysosome-like bodies. We suggest that antiserum C1 recognizes cerebellin precursor(s) and antiserum R2 mature peptide(s) and perhaps degradation product. There is structural homology between cerebellin and residues 625-641 of the polyimmunoglobulin transporter. The functional implications of this homology and other possible roles of cerebellin are discussed.

The polypeptide PEP-19 is a marker for Purkinje neurons in cerebellar cortex and cartwheel neurons in the dorsal cochlear nucleus.

This light and electron microscopic immunocytochemical study shows that the polypeptide PEP-19, a presumptive calcium binding protein specific to the nervous system, represents an excellent marker for cerebellar Purkinje cells and dorsal cochlear nucleus (DCoN) cartwheel cells. The polypeptide clearly reveals the entire populations of both types of neurons, including their complete dendritic and axonal arborizations. Other PEP-19 containing neurons in the two regions display weak immunoreactivity restricted to the cell body or to cell body and principal dendrites. Electron microscopic localization of PEP-19-like immunoreactivity reveals similarities between this polypeptide, parvalbumin, and a 28K vitamin D-dependent calcium binding protein. However, calmodulin, which is expressed in both Purkinje and granule cells, may differ from PEP-19. Similarities between the organization of the cerebellar cortex and the DCoN superficial layers have been known for some time, with several types of neurons in one system having their presumed homologue in the other. These data provide further support for the proposed structural and functional homology between Purkinje and cartwheel neurons, and establishes PEP-19 as a useful marker for examining degeneration of these two neuronal populations in murine cerebellar mutants.

Histochemical localization of acetylcholinesterase in the cochlear and superior olivary nuclei. A reappraisal with emphasis on the cochlear granule cell system.

The present account reconsiders the acetylcholinesterase (AChE) staining pattern of the cochlear nuclei with special emphasis on positively stained afferents from the olivocochlear neurons to the cochlear granule cells system. The main part of the study is based on AChE- and silver-stained sections of normal and brainstem-operated cats. AChE-stained sections of normal mouse, cat and chinchilla are used for comparative purposes. The rat superior olive contains three types of AChE-positive neurons probably contributing to the olivocochlear bundle; densely stained large neurons of the periolivary region, densely stained small neurons at the margin of the lateral superior olive (LSO), and weakly stained small neurons within LSO. Largely uncrossed fibers, probably collaterals of the olivocochlear bundle, enter the cochlear nuclei via three routes, defined here as the strial, subpeduncular and ventral routes. Collectively they form a terminal fiber plexus in certain portions of the granule cell domain, but with some fibers branching in the extragranular regions of the nuclear complex as well. The individual fibers end in a fashion resembling cerebellar mossy fibers. The cochlear nuclei in addition contain conspicuous dense patches of precipitate, which, like the AChE-positive fibers, appear after short incubation and are mainly restricted to the granule cell domain. In contrast to the fibers, however, they are resistant to central deafferentation and therefore may represent intrinsic structures of the granule cell system. Moreover, there is a diffuse neuropil precipitate which grows in distribution and density with incubation time. It is present both in granular and extragranular areas of the complex and is partly dependent upon the integrity of the weakly stained trapezoid body. In spite of considerable interspecies variations with regard to the described AChE-positive elements, these are present also in mouse, cat, and chinchilla. The significance of the findings and of the interspecies differences are discussed. A simplified terminology of the superior olivary complex is proposed.

Stellate neurons in rat dorsal cochlear nucleus studies with combined Golgi impregnation and electron microscopy: synaptic connections and mutual coupling by gap junctions.

Stellate neurons in the outer two layers of the rat dorsal cochlear nucleus (DCN) were studied by the Golgi-EM method. Stellate cell bodies are usually spherical or ovoidal and range from 9 microns to 14 microns in mean diameter. The smallest cells are situated underneath the ependymal layer and the largest cells in layer 2. Primary dendrites are short, thin and smooth and arise abruptly from the perikaryon, without a tapering main stem. Meandering secondary and tertiary dendrites extend in all directions, carry few pleomorphic spines lacking a spine apparatus and often show artifactual beading. The axons are impregnated only for a short distance (10-45 microns). The nucleus is indented, the nucleolus varies in position, and the chromatin, evenly dispersed in the centre, forms small clumps along the nuclear envelope. The cytoplasm is rich in free polyribosomes and contains scattered cisterns of granular endoplasmic reticulum. Varicosities of thin fibres, containing round synaptic vesicles, form asymmetric synapses on perikarya, dendritic shafts and spines of stellate cells. Such fibres run parallel to the long axis of the DCN or are oriented radially and are interpreted as axons of cochlear granule cells. Two kinds of bouton containing pleomorphic vesicles, one kind electron lucent and the other electron dense, form symmetric synapses on perikarya and dendritic shafts of stellate cells. The lucent boutons occur more frequently than the dense boutons, especially on the distal dendritic branches. The boutons with pleomorphic vesicles presumably represent terminals of local circuit neurons, probably the stellate and cartwheel cells. In addition, stellate cells show numerous dendro-somatic and dendro-dendritic appositions characterized by gap junctions and puncta adhaerentia. Most of the dendrites involved in these appositions resemble stellate cell dendrites and it is concluded that DCN stellate cells are coupled electrotonically with one another. The axons of stellate cells acquire a thin myelin sheath. Since the Golgi impregnation did not stain axons of stellate cells past this point, we were unable to demonstrate the synaptic targets of stellate cells.

Immunocytochemical identification of GABAergic neurons in the main olfactory bulb of the rat.

With the aid of a sheep antiserum against rat brain glutamate decarboxylase (GAD), the endogenous marker for GABAergic neurons, we have labeled immunocytochemically various types of nerve cells in the main olfactory bulb of rats, with and without topic injections of colchicine. The peroxidase-antiperoxidase procedure was applied to floating Vibratome and frozen sections. A large part of the periglomerular cell population and practically all granule cells in the deep layers contain GAD-like immunoreactivity in untreated rats, while tufted and mitral cells (the projection neurons) are unstained. This observation confirms a previous study with a rabbit antiserum against mouse brain GAD, which suggested that GABAergic neurons with presynaptic dendrites contain high somatal concentrations of GAD. We show, however, that immunostaining of granule cell bodies decreases progressively from the internal plexiform layer to the deep portion of the granule cell layer. Many cell processes in the glomeruli are densely stained. They presumably represent synaptic gemmules of the numerous GAD-positive periglomerular cells, which thus could provide initial, inhibitory modulation of the afferent input. In the external plexiform layer immunostaining of the neuropil is substantially denser in the superficial half than in the deep half. This may reflect a corresponding gradient of inhibition related to unequal frequency of occurrence of synaptic gemmules of granule cell dendrites. Alternatively such a graded immunostaining of cell processes could be related to the corresponding gradient in the density of immunostaining of granule cell bodies in the deep layers, in accordance with recent data indicating that superficial and deep granule cells project their ascending dendrites respectively to superficial and deep portions of the external plexiform layer. Furthermore, we have demonstrated the presence of additional classes of GAD-positive neurons, microneurons in the external plexiform layer, small neurons in the periglomerular region, the external plexiform layer, the mitral cell layer, the internal plexiform layer, and medium-size neurons in the granule layer and the white matter. The small- and medium-size GAD-positive neurons appear weakly immunoreactive in untreated rats, but become densely stained after topic colchicine injection. Such cells presumably lack presynaptic dendrites and may correspond to different types of short axon cells demonstrated by the Golgi method.(ABSTRACT TRUNCATED AT 400 WORDS)

Zinc-aldehyde fixation for light-microscopic immunocytochemistry of nervous tissues.

Two procedures are described for vascular perfusion of the nervous system with a zinc-aldehyde fixative. The procedures, simple and economical, combine the advantages of perfusion fixation with an aldehyde solution and matrix stabilization by a mordating agent, and improve the sensitivity of the peroxidase-antiperoxidase (PAP) method for the immunocytochemical localization of several antigens. Procedure A is intended for the light-microscopic immunostaining of cellular elements containing high concentrations of antigen. Penetration of the immunoreagents is adequate without the use of detergents. Procedure B is particularly advantageous for the light-microscopic immunostaining of cellular elements that contain low concentrations of antigen, and for high-resolution microphotography. With procedure B, the tissue penetration of immunoreagents is more limited than with procedure A; however, neuronal cell bodies and dendrites are more easily penetrated by the immunoreagents than are axons. Neuronal cell bodies and dendrites thus become clearly detectable in the light-microscope, even when they are surrounded by numerous immunoreactive axon terminals, and especially after the blockage of axoplasmic transport by the topical injection of colchicine.

Central GABAergic innervation of neurointermediate pituitary lobe: biochemical and immunocytochemical study in the rat.

Activity of glutamic acid decarboxylase GluDCase, the biosynthetic enzyme of gamma-aminobutyric acid (GABA) was measured in low-speed homogenate supernatant of the neural and intermediate (neurointermediate) lobe (28--30 pmol of CO2 per microgram of protein per hr) and of the anterior lobe (2--4 pmol of CO2 per microgram of protein per hr). In the neurointermediate lobe, stalk transection reduced the GluDCase activity by more than 95%. By using an antiserum to rat brain GluDCase and the unlabeled antibody--peroxidase method of Sternberger, GluDCase immunoreactivity was localized in many terminals within the neurointermediate lobe of the hypophysis. In pars intermedia, immunoreactive terminals occurred in apposition to secretory cells and to glial cells and were near nonimmunoreactive axonal profiles; in pars neuralis they were apposed to pituicytes and to unlabeled axons including the neurosecretory terminals and were along fenestrated portal capillaries. GluDCase immunoreactive axons terminals exhibited diverse morphological features and would not have been identified as a distinct population without the GluDCase antiserum. No GluDCase-immunoreactivity was found in the anterior pituitary lobe. Stalk transection abolished GluDCase immunoreactivity in the neurointermediate lobe. These data provide biochemical and morphological evidence for a central GABAergic innervation of neural and intermediate lobes of the hypophysis.

Fine structure of granule cells and related interneurons (termed Golgi cells) in the cochlear nuclear complex of cat, rat and mouse.

This paper describes the fine structure of granule cells and granule-associated interneurons (termed Golgi cells) in the cochlear nuclei of cat, rat and mouse. Granule cells and Golgi cells are present in defined regions of ventral and dorsal cochlear nuclei collectively termed "cochlear granule cell domain'. The granule cells are small neurons with two or three short dendrites that give rise to a few branches with terminal expansions. These participate in glomerular synaptic arrays similar to those of the cerebellar cortex. In the glomeruli the dendrites form short type 1 synapses with a large, centrally-located mossy bouton containing round synaptic vesicles and type 2 synapses with peripherally located, smaller boutons containing pleomorphic vesicles. The granule cell axons is thin and beaded and, on its way to the molecular layer of the DCN, takes a straight course, which in ventral nucleus is parallel to the pial surface. Neurons of the second category resemble cerebellar Golgi cells and occur everywhere interspersed among the granule cells. They are usually larger than the granule cells and give rise to dendrites which may branch close to and curve around the cell body. The dendrites contain numerous mitochondria and are laden with thin appendages, giving them a hairy appearance. Both the cell body and the stem dendrites participate in glomerular synaptic arrays. Golgi cell glomeruli are distinguishable from the granule cell glomeruli by unique features of the dendritic profiles and by longer, type 1 synaptic junctions with the central mossy bouton. The Golgi cell axon forms a beaded plexus close to the parent cell body. The synaptic vesicle population of the mossy boutons suggests that they are a heterogeneous group and may have multiple origins. Apparently, each of the various classes participates in both granule and Golgi cell glomeruli. The smaller peripheral boutons with pleomorphic vesicles in the two types of glomeruli may represent Golgi cell axons which make synaptic contacts with both granule and Golgi cells. The Golgi cell axons which make synaptic contacts with both granule and Golgi cells. The Golgi cell dendrites, on the other hand, are also contacted by small boutons en passant with round synaptic vesicles, which may represent granule cell axons. A tentative scheme of the circuitry in the cochlear granule cell domain is presented. The similarity with the cerebellar granule cell layer is striking.

The fate of tritium-labeled reserpine in the chick embryo: a preliminary report.

After a single administration of EH-reserpine, 10 mugm 2.5 microCi, into the yolk of fertilized chicken eggs, gross radioactivity (reserpine plus degradation products) and the unchanged labeled drug, separated by thin layer chromatography, were assayed on the 8th and 19th day of incubation. Nanogram per gram concentrations of unchanged 3H-reserpine were recovered at both times. The 3H-reserpine recovered in the whole egg on the 8th day of incubation accounted for up to 20% of the administered dose. On the 19th day of incubation, brain showed the largest share (28%) of 3H-reserpine as a percentage of gross radioactivity of all organs investigated. Reserpine underwent considerable biodegradation in the developing chick embryo, but the concentrations of unchanged drug recovered in embryonal tissues throughout development were of the same order as those persisting in target organs of rats given a pharmacological dose of reserpine.

The length of parallel fibers in the cat cerebellar cortex. An experimental light and electron microscopic study.

Experimental light and electron microscopic studies were carried out to determine the length of parallel fibers in the cat cerebellar cortex. Using a fine surgical knife, vermal and hemispheral folia were cut perpendicular to their long axis. The animals were sacrificed 1-10 days after the operation. Sections of the transected folia were then stained with a Fink-Heimer procedure. The resulting degeneration appeared as fine dots that extended lateral to the lesion, as predictable from the course of the parallel fibers. Densitometer readings indicate that the density of degeneration declines gradually lateral to the lesion. The specificity of the silver impregnation was checked by processing silver stained sections for electron microscopy. This confirmed the location of the silver precipitate on degenerating parallel fibers. The pattern of parallel fiber degeneration in the molecular layer has a trapezoidal configuration centered on the lesion. The shorter parallel fibers are located at the base of the molecular layer and extend for 5 mm. The parallel fibers become progressively longer as they approach the pial surface where they attain a maximum length of 7 mm. Our studies suggest that in folia longer than 7 mm parallel fibers are 6 mm long on the average. In addition, it was determined on Golgi sections that the average center-to-center distance between en passant boutons of individual parallel fibers is 5.2 mum. The data indicate that an average parallel fiber, 6 mm long, forming approximately 1100 boutons, may synapse with each Purkinje dendritic tree it traverses.

Mode of distribution of aminergic fibers in the cerebellar cortex of the chicken.

The cerebellar cortex of adult hens contains a dense plexus of thin varicose nerve fibers which display a formaldehyde-induced green fluorescence. This plexus is not distributed at random in the cortical layers. Within the granular layer the plexus forms a netlike pattern. The fiber branches, which have numerous varicosities, are predominantly oriented in the traverse plane of the folium. In the molecular layer the fluorescent plexus shows some variations in the convex, flat and concave portions of the folia. Many of the fluorescent branches are oriented parallel to the course of the folium. They arise from a T-division of radially oriented axons resembling parallel fibers in Golgi sections. The meshes of the fluorescent plexus in the granular layer measure 10-60 mu. In the molecular layer (top of the folia) there are about 30 fluorescent fibers per 100 mu2. The fluorescent fibers originate from the locus coeruleus and form a rostral and a caudal bundle in the cerebellar peduncle. The mode of distribution of the fluorescent fibers in the cortical layers seems to depend on the organization of the innervated tissue. Light microscopy suggests that the aminergic fibers innervate more than one class of cerebellar neurons.