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At least 325 records · Page 18Linked to original sources

Latent infections in spinal ganglia with thymidine kinase-deficient herpes simplex virus.

A herpes simplex virus type 1 variant [C239(TK-)] harboring a deletion in the thymidine kinase (TK) gene was assessed for capacity to establish latent infections. Outbred Swiss Webster mice were inoculated on both hind footpads, and numbers of neurons expressing latency-associated transcript and amounts of viral DNA in latently infected lumbosacral spinal ganglia were scored. C239(TK-) established levels of latent infection that were only slightly lower than those found for either a TK rescued variant of this agent or the parent wild-type KOS. However, in contrast to the TK+ viruses, C239(TK-) could not be reactivated when spinal ganglia were cultured in vitro. The results presented show that expression of the viral TK gene plays no major role in establishment of the latent state but that it functions during reactivation of latent virus from explanted ganglia maintained in vitro.

Animals↗

Ratios between number of neuroglial cells and number and volume of nerve cells in the spinal ganglia of two species of reptiles and three species of mammals.

We studied the ratios between number of neuroglial (=satellite) cells and number and volume of neurons with which they are associated in the spinal ganglia of two species of reptiles (lizard and gecko) and three species of mammals (mouse, rat, and rabbit). In all five species, we found that the number of satellite cells associated with a nerve cell body increased with increasing volume of the latter. This result shows that there is a quantitative balance between neuroglia and nerve tissue in spinal ganglia. This balance seems to be maintained by a tight regulation of the number of satellite cells. We also found that the mean volume of nerve cell body corresponding to a satellite cell was lower for small neurons than for large ones. Since satellite cells metabolically support spinal ganglion neurons, the metabolic needs of small neurons are better satisfied than those of large ones. For a nerve cell body of a given size, the number of associated satellite cells did not differ between the lizard and gecko, nor between the mouse, rat, and rabbit. However, this number was significantly smaller in the reptiles than in the mammals. This result could be explained by the lower metabolic rate in the nervous system of poikilotherms than mammals, or could have a phylogenetic significance. These two interpretations are not mutually exclusive.

Animals↗

[Special forms of synaptic junctions in cultures of dissociated mammalian spinal cord and spinal ganglia].

The ultrastructural study of cells in the monolayer culture of dissociated spinal cord and spinal ganglia of mouse embryos has been performed. The results obtained show that in the course of differentiation of completely isolated cells of the spinal cord special forms of synaptic contacts may appear. They are typical of the spinal cord of phylogenetically inferior animal species. These "mixed" synaptic contacts having properties both of electrical and of chemical synapses seem to represent phylogenetically determined processes of synaptogenesis.

Animals↗

Increase in number of the gap junctions between satellite neuroglial cells during lifetime: an ultrastructural study in rabbit spinal ganglia from youth to extremely advanced age.

This study investigated quantitative aspects of the gap junctions between satellite neuroglial cells that envelope the spinal ganglion neurons in rabbits aged 1 year (young), 3.6 years (adult), 6.7 years (old), and 8.8 years (very old). Both the total number of gap junctions present in 30,000 microm2 of surface area occupied by perineuronal satellite cells, and the density of these junctions increased throughout life, including the extremely advanced age. By contrast, the mean length of individual gap junctions did not change with age. Thus, the junctional system which provides morphological support for the metabolic cooperation between satellite cells in rabbit spinal ganglia becomes more extensive as the age of the animal increases. These results support the hypothesis that the gap junctions between perineuronal satellite cells are involved in the spatial buffering of extracellular K+ and in neuroprotection.

Aging↗

[Influence of intrauterine asphyxia on the development of spinal ganglia].

In 17- and 18-day-old rat embryos and in 10-, 30-day-old newborn rats, the development of the spinal ganglia neurons was investigated under normal conditions and after intrauterine asphyxia. It was stated that increase in the profile field of the neuronal body development proceded differently before and after birth. Before birth, the most intensive growth was noted in large ganglial cells, while after birth--in middle and especially small cells. It was stated that embryos subjected to asphyxia in the last fourth of their intrauterine life suffered from chronic disorders in their neuronal cells, their intensity increasing with time reaching maximum to the first month of life. This process involved mainly the cells of middle and small size.

Animals↗

Peripheral chromatolysis in spinal ganglia neurons after aortic ligature in dog.

The chromatolytic response of neurons to repeated aortic ligature (2 X 40 min) was studied in lumbar spinal ganglia in dogs with 1, 2, 3 and 6 days survival. The cells were examined by electron microscopy and morphometry. The early changes of endoplasmic reticulum (ER) were characterized by a degranulation of its cisterns and disaggregation of polysomes and resulted in reduction of membrane component remarkable mainly in the peripheral zone of cytoplasm. The chromatolytic neurons were more numerous after a 2 days survival and most of them (60%) showed signs of peripheral chromatolysis. Morphometric analysis revealed a significant decrease in ER area and an increase in its cistern dispersion as well as a reduction of ER membrane component (2 days). Changes of the observed parameters with longer period of survival (6 days) turned to normal level.

Animals↗

Morphofunctional characteristics of neurons in the spinal ganglia of the dog in the post-distraction period.

The aims of the present work were to study the morphofunctional state of neurons in the spinal ganglia and to perform a comparative analysis of changes in neuron-glial relationships after lengthening of the hindlimb of mongrel dogs by 14-16% of initial at different rates. Longitudinal serial sections of thickness 5 microm of the L6, L7, and S1 ganglia (n = 36) stained with thionine and cresyl violet by the Nissl method and hallocyanine and chromic alum by the Einarson method were examined. Reversible transformations of the structure of some neurons were seen at 45-48 days, these consisting of hyperchromia of the cytoplasm and nucleus, peripheral chromatolysis, displacement of the nucleolus, and increases in the quantities of perineuronal and interneuronal gliocytes. Changes were most marked in the ganglia on the side of limb lengthening at a rate of 3 mm/day, while the smallest changes were seen on the side contralateral to limb lengthening at a rate of 1 mm/day.

Animals↗

Paired helical filaments in rat spinal ganglia following chronic alcohol administration: an electron microscopic investigation.

Young Wistar rats were given a 15% (v/v) ethanol solution ad libitum for at least 6 months, spinal ganglia (C6-7 and L1-2) in some of the experimental animals showed paired helical filaments. These curvilinear profiles consisted of 10 nm filaments with the twist every 35nm. There was also an increase in granular material and in nematosomes. Whether these features may be caused by an impaired cerebral protein biosynthesis is discussed.

Animals↗

Androgen target cells in spinal cord, spinal ganglia, and glycogen body of chick embryos. Autoradiographic localization.

After injection of 3H dihydrotestosterone, concentration and retention of radioactivity occur in nuclei of certain neurons in the spinal cord and spinal ganglia as well as in dorsal and ventral root cells of chick embryos at day 10, 12, and 18. Cell of the glycogen body show nuclear labeling at day 12, but not at day 18. In motor neurons in the midlumbar and midbrachial regions in lamina IX and in single neurons in laminae I/II, the nuclear retention of androgen is strongest, but relatively weak in ventral horn cells in thoracic and sacral segments. Neurons with nuclear labeling are also found scattered in other laminae of the dorsal and ventral horns as well as in the lateral column. When unlabeled dihydrotestosterone is administered before 3H dihydrotestosterone, nuclear uptake of radioactivity is prevented, which is not the case, when estradiol is used. The results from these autoradiographic studies indicate the presence of nuclear receptors and suggest androgen effects during prenatal stages of development.

Animals↗

Lysosomes in normal and degenerating neuroblasts of the chick embryo spinal ganglia. A cytochemical and quantitative study by electron microscopy.

Lysosomes were studied by both cytochemical and quantitative methods in normal and degenerating neuroblasts of the chick embryo spinal ganglia. In normal neuroblasts (primitive and intermediate neuroblasts) both primary lysosomes and autophagic vacuoles were found; these organelles were usually located in the region containing the Golgi complex. In degenerating neuroblasts lysosomes appeared sharply decreased in number with respect to normal neuroblasts. Moreover, lysosomes were always evident as intact organelles surrounded by a membrane and the acid phosphatase activity appeared localized exclusively within these bodies. A diffuse distribution of acid phosphatase activity was only found in a limited number of cases during the terminal stage of the process. Possibly in these cases the enzymatic activity depended on the cells which enveloped the degenerated neuroblast remnants. The present results indicate that lysosomes do not play a primary role in the degenerative process studied.

Acid Phosphatase↗

Satellite cells in developing spinal ganglia. An immunohistochemical study.

The present immunohistochemical study investigates the presence and distribution of S-100-containing glial cells in the early stages of development in human spinal ganglia. From the earliest ages investigated immunoreactive cells could be detected in a continuous layer at the periphery as well as inside ganglionic rudiments in close relationship with neural elements, both at the light and ultrastructural levels. The possibility that these glial cells, exhibiting such a distinctive distribution, play a modulatory role on microenvironmental influences during maturation could be taken into account. Neither glial fibrillary acidic protein nor myelin basic protein could be detected at the ages investigated.

Embryonic and Fetal Development↗

Relationships between vasculogenesis and morphogenesis in the chick embryo spinal ganglia.

By means of India ink injections in chicken embryos from the 3rd to the 14th incubation day, the development of the vascular pattern in the thoracic and lumbar spinal ganglia has been studied. A rather precise correlation has been observed between the successive steps in the formation of the endoganglionic vessel network and the ordered sequence of the proliferation and differentiation processes of the ganglionic neuroblasts: in fact, the developing vascular pattern seems to conform to the morphogenetic changes gradually undergone by the nervous substratum.

Animals↗

A comparison of the density of microtubules in the central and peripheral axonal branches of the pseudounipolar neurons of lizard spinal ganglia.

The number and density of microtubules were determined in cross sections of the two branches (central and peripheral) of the bifurcating axon of the pseudounipolar neurons of the lizard thoracic spinal ganglia. In both the central and peripheral branches the average number of microtubules rose, while the microtubular density decreased with an increase in the cross-sectional area of the axonal branch: More precisely, a linear relationship was observed between the logarithm of the microtubular density and the cross-sectional area of the axonal branch. Both the average number of microtubules per cross section of the axonal branch and the microtubular density were found to be significantly lower in the central than in the peripheral branch. Since the amount of material carried by fast transport was found by other authors to be greater in the peripheral than in the central branch, a positive correlation seems to exist between microtubular density and the quantity of material carried by fast transport along the two branches of the axon in pseudounipolar neurons. Such a correlation suggests that microtubules may be somehow involved in the fast transport of material along the axon. The average densities of microtubules were found to be the same comparing two sets of unmyelinated and myelinated central (or peripheral) branches of corresponding size. Therefore, different microtubular densities usually observed in unmyelinated and myelinated axons appear to be correlated with the different size ranges of the two types of axon rather than with the absence or presence of the myelin sheath.

Animals↗

Effect of cerebral neurite-stimulating protein on morphogenesis of organotypical culture of spinal ganglia.

We have extracted a cationic protein with a molecular weight of 15,000 kdalton from the hemispheres of rat and bovine brain. Addition of the protein to the nutrient medium of the organotypical culture of chick embryo spinal ganglia results in a considerable (2-2.5 fold) increase in the growth zone of the explants. The neurite-stimulating effect of the protein is observed at a concentration of 10 ng/ml. We observed an intensive longitudinal growth of neurites, an increase in their amount per unit area, a considerable intensification of ramification, and formation of strong anastomoses, numerous dense plexuses, and arcades. Fasciculi of neurites covered with glia are formed. The cerebral neurite-stimulating protein is evidently one of the neuron-growth factors regulating development of the nervous system in the body.

Animals↗

[Representation of skeletal muscles in the spinal ganglia of the cat].

In 5 experimental and 3 control cats the m. extensor digitorum longus (MEDL) has been extirpated in both extremities. In 10 days the cats are sacrificed with a lethal dose of pentobarbital. In the spinal ganglia, which are supposed to innervate the MEDL, the state of chromatophilic substance is investigated. The amount of neurons with chromatolysis is determined. A new source of the MEDL sensitive innervation--ganglion SIII is revealed. Certain asymmetry in the MEDL ganglia innervation is noted in the left and right sides.

Animals↗

Origin of renewed spinal ganglia during tail regeneration in urodeles.

The source of the cells which form the spinal ganglia within the regenerating urodele tail is not yet indisputably known. Classical and modern experimental approaches trace the spinal cord as the most probable source. The aim of the present study was to further investigate this item by conventional histology, counting of mitotic figures, and estimating the labeling index. The main results can be summarized as follows: (a) The regenerated part of the tail contained only two bilaterally asymmetrical pairs of ganglia, with respect to the rostrocaudal (anterior-posterior) axis. (b) The anterior ganglia were slightly differentiated and appropriately localized; therefore, analysis was performed mainly in the posterior, still developing ganglia. (c) An anatomical continuation between the ventrolateral side of the regenerated spinal cord and the laterally forming spinal ganglion was noticed. There was some indication that many cells migrated out from the spinal cord towards the spinal ganglion, through the ventral root. (d) The mitotic and the labeling index along the regenerated spinal cord exhibited individual peaks near the level of each developing ganglion. The last two observations corroborate and reinforce the prevailing view that the progenitors of the spinal ganglion cells which are formed in the regenerating tail are of spinal cord origin.

Animals↗

[Changes in the blood vessels of the spinal cord and spinal ganglia following chronic stimulation of the lumbar regions of the sympathetic trunks and gangliosympathectomy].

Morphological studies in 40 rabbits demonstrated that chronic irritation of the lumbar sympathetic trunks resulted in more pronounced architectonic changes, in vessel walls and in neurons of the lumbar sympathetic ganglia in 15 days than did the bilateral lumbar gangliosympathectomy at the same time. In both series of experiments more prominent changes were noticed in the spinal ganglia than in the spinal cord, that could be explained by different degree of lesions in the nerves supplying them and by organic specification of their angioarchitectonics. The data obtained made it possible to include novocain block (anesthesia) into complex therapy to manage spinal apoplexy in clinic.

Animals↗

[Effect of a cerebral neurite-stimulating protein on the morphogenesis of an organotypical culture of spinal ganglia].

Cationic protein with molecular mass of 15,000 kDa has been extracted from the hemispheres of the rat and bovine brain. Addition of the protein into nutritive medium of the organo-typical culture of the chick embryo spinal ganglia results in a considerable (by 2-2.5 times) increase of the growth zone in the explants. Neurite-stimulating effect of the protein is demonstrate dat concentration of 10 ng/ml. An intensive longitudinal growth of neurites is observed, increase of their amount per area unit, an essential intensification of ramification, formation of powerful anastomoses, numerous dense plexuses and arcades. Fasciculi of neurites covered with glia are formed. The cerebral neurite-stimulating protein is, evidently, one of neuron-growing factors, regulating development of the nervous system in the organism.

Animals↗