Biomedical subjects
Publications and source records attributed to L F Borges.
Ranvier's method of staining tissue whole mounts with gold chloride to visualize nerve fibers was modified by lengthening the incubation time in gold chloride and reducing the time in acidulated water. These simple modifications of an old technique give consistent impregnation of nerve fibers with light background staining in whole mounts of cornea and dura.
Many fluorescent dye compounds are transported by axons in retrograde and anterograde directions. In the present study the uptake and retrograde axonal transport of 4 chemically related fluorescent dyes was evaluated in the peripheral nervous system of adult mice. Anterograde transport was studied in the corticospinal tract of adult rats. In addition to confirming the previously reported intra-axonal transport of Rhodamine-B-isothiocyanate, we report the transport of Rhodamine-X-isothiocyanate. Sulforhodamine-101-acid chloride and Lissamine rhodamine-B-sulfonyl chloride. By using the fluorescence intensity of the labeled motor and sensory neurons as well as cell counts of fluorescently labeled motor neurons and percent of labeled dorsal root ganglia (DRG) cells, we were able to quantitate the amount of retrograde transport of a given fluorescent compound. The two dyes with isothiocyanate groups available for conjugation were transported in higher amounts compared to the dyes containing sulfonyl chloride groups. No anterograde transport in the corticospinal system was observed. We conclude that the 4 dyes described are useful for retrograde neuroanatomical tracing experiments. We describe methods for quantifying the amount of retrograde transport by peripheral motor and sensory neurons.
The techniques of neural transplantation are almost 100 years old. As these techniques begin to be used to treat human neurological disorders, it is important to remember the contributions of the many investigators who have advanced this fascinating area of neurobiology.
This report describes a patient with communicating syringomyelia associated with enlarged cerebral ventricles who was managed by placing a ventriculoperitoneal shunt. His clinical improvement was rapid and dramatic. A comparison of preoperative and postoperative magnetic resonance scans documents shrinkage of the cervical syrinx.
The retrograde intraaxonal transport of several anthracycline antibiotics was assessed in the peripheral nervous system of adult mice. Despite certain chemical similarities, the intraaxonal transport of these molecules was variable and could be correlated with the structure of the aminosugar at the R-2 position. One particularly interesting compound, 4'-deoxydoxorubicin, was transported by dorsal root ganglia axons, but not by the axons of ventral horn neurons. These observations suggest that the sugar component of a molecule may be important for its intraaxonal transport in the peripheral nervous system.
The topography of choline acetyltransferase immunoreactivity was studied in the rat spinal cord with a monoclonal antibody. Cholinergic fibers were most prominent in lamina III of the dorsal horn and originated from cholinergic neurons within the spinal cord. Lamina X, which was rich in cholinergic neurons and fibers, provided cholinergic interconnections between the dorsal, intermediate and ventral gray. Within the ventral gray, choline acetyltransferase immunoreactive boutons were found on motor neurons. This study suggests that the cholinergic innervation of the spinal cord arises from neurons intrinsic to the spinal cord. The cholinergic neurons within the spinal cord may provide several, overlapping levels of regulation of spinal cord neurons.
Horseradish peroxidase conjugated to wheat germ agglutinin (HRP-WGA), and bisbenzimide (a fluorescent dye) were used as retrograde axonal tracers to examine whether or not intracranial and extracranial trigeminal afferents represent divergent axon collaterals. HRP-WGA was applied to the proximal segment of the middle cerebral artery and bisbenzimide was injected into a branch of the ophthalmic nerve in 5 cats. Histologic examination of the ipsilateral trigeminal ganglion revealed HRP-labeled cell bodies located among clusters of cells exhibiting bisbenzimide fluorescence. Cells containing both labels were not observed. These results support the concept that divergent axon collaterals are probably not involved in the pathogenesis of referred pain during vascular headache.
Cerebellar Purkinje neurons accumulated propidium iodide, granular blue, and horseradish peroxidase conjugated to wheat germ agglutinin but not unconjugated horseradish peroxidase, bisbenzimide, or Evans blue when these compounds were infused into the lateral cerebral ventricles of awake, unrestrained rats. Accumulation of propidium iodide by Purkinje neurons of the vermis was associated with a reproducible behavioral abnormality characterized by truncal tremor, ataxia, and nystagmus. Both the accumulation of propidium iodide in Purkinje cells and the behavioral abnormality were prevented by prior intracerebroventricular administration of ouabain or colchicine, drugs that block neuronal transport processes. The ability of cerebellar Purkinje neurons to extract small and large molecules from the cerebrospinal fluid has important implications for their physiology and pathology.
We studied a patient with multiple myeloma who had immunologically identified myeloma light chain proteins within neurons projecting beyond the blood-brain barrier, but not within intrinsic neurons of the spinal cord, brain stem, and cerebral cortex. There was a possibility that these myeloma light chain proteins or their immunologically recognizable fragments were transported intra-axonally by human peripheral nerves. Myeloma light chain proteins were also identified within cerebellar Purkinje's neurons. This labeling may have been secondary to transport from cerebrospinal fluid.
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40 mice (C57BL/6J) 2, 3, 6, and 10 d old were injected intraventricularly with 2% wheat germ agglutinin (WGA) or soybean agglutinin (SBA). The transport of lectins from the ventricular cerebrospinal fluid (CSF) into brain parenchyma was studied by an unlabelled antibody technique ( BORGES and SIDMAN 1982). The granule product of the immunohistochemical reaction was found in the cytoplasm of ventricular ependymal cells, the choroid plexus and meninges in all age groups studied. Penetration of lectins into brain parenchyma was higher in younger animals and at more immature-cell-surrounded parts of lateral and the IVth ventricle. The stain product was dispersed throughout the neuropil excepting cell nuclei. Higher concentration of lectins appeared in nerve cell cytoplasm of some regions of the brain of younger animals (P2 to P3); in 10 d old mice granules of stain appeared in the cytoplasm of PURKINJE cells and pyramidal neurons of the hippocampus. A fiber-like staining, apparent especially in large commissures adjacent to brain ventricles (corpus callosum, fornix hippocampi) in all age groups, suggests that lectins are transported within axons, even at the earliest postnatal ages. Unlike WGA, densely stained glial cells appeared in parenchyma of SBA injected animals, especially of the younger age group (P3 to P6). The results of this study confirm earlier findings that macromolecules within the ventricular CSF can penetrate into brain parenchyma but suggest that the penetration is higher in less mature animals and at the ventricle regions surrounded by less differentiated parenchyma.(ABSTRACT TRUNCATED AT 250 WORDS)
Trigeminal nerves provide the principal afferent pathways for the transmission of intracranial and extracranial head pain. This study, using two retrograde axonal tracers, demonstrated that first division afferents projecting to intracranial and extracranial targets are not commonly axon collaterals of the same neuron. Therefore, divergent axon collaterals probably are not responsible for the phenomenon of referred pain within the first trigeminal division.
Two patients with large vascular carotid body tumors underwent preoperative intravascular embolization of the major arterial feeders. The tumor vascularity was reduced markedly, and complete surgical extirpation was accomplished without difficulty. The literature on carotid body tumors is briefly reviewed. The role of preoperative embolization in the treatment of these difficult tumors is emphasized.
The inferior olivocerebellar projection of the normal inbred C57BL/6J mouse was visualized after anterograde transport of horseradish peroxidase conjugated to the lectin wheat germ agglutinin (HRP-WGA conjugate). Following injections of HRP-WGA conjugate which filled the entire inferior olivary nucleus on one side, olivocerebellar fibers were followed across the midline of the medulla and into the contralateral cerebellar cortex via the inferior cerebellar peduncle. The molecular layer was heavily but nonuniformly labeled in all cortical lobules. Labeled olivocerebellar fibers within the contralateral cerebellar molecular layer were grouped into distinct bands separated by regions of molecular layer containing no labeled fibers. The bands of olivocerebellar terminals in the molecular layer were in turn organized into distinct sets of bands oriented in parasagittal planes. The organizational basis for this banding pattern, previously recognized by other workers in other mammalian and avian species, remains unknown.
The binding and axonal transport of six lectins were studied in the peripheral nervous system of adult mice by an immunocytochemical method. After injection into muscle and subcutaneous sites, lectins known to bind preferentially N-acetylglucosamine or mannose sugars were transported axonally to ventral horn and dorsal root ganglion neurons. Twelve to 96 hr postinjection, these lectins were bound at the injection site to neuromuscular junctions, muscle spindles, and cutaneous nerves. Lectins known to bind preferentially N-acetylgalactosamine or galactose sugars, by contrast, were transported only to dorsal root ganglion neurons. Except for Sophora japonica agglutinin, these lectins were bound at the injection site only to cutaneous nerves. These differences in axonal transport were seen also when the lectins were applied directly to the proximal end of a transected mixed nerve.
Despite advances in neurosurgical therapeutics, cerebrospinal fluid shunt infections have continued to complicate the management of patients with shunted hydrocephalus. Although various factors have been proposed to explain the pathogenesis of these infections, they have remained poorly understood. This in vitro study determined the ability of human neutrophils and monocytes to adhere to two types of shunt catheters and to phagocytose bacteria. These white blood cells failed to adhere in normal numbers to the catheters and failed to ingest fully a bacterial inoculum on the catheters' surfaces. While in contact with the shunt apparatus, the neutrophils also exocytosed myeloperoxidase, a major component of the intracellular microbicidal system. These observations suggest that the shunt apparatus may diminish the effectiveness of the hosts' defenses at the site of implantation.
Two recently encountered patients with the anterior tarsal tunnel syndrome are presented. The various aspects of this probably under-recognized syndrome are discussed. Evidence is presented that this syndrome may be the result of abnormal stretch of the deep peroneal nerve.