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C Ide

Publications and source records attributed to C Ide.

At least 91 records · Page 5Linked to original sources
PubMed1990

An experimental study of nerve regeneration through chemically treated allografts.

We carried out experiments in rabbits to determine whether treating nerve transplants with gradually increasing concentrations of ethanol, ether and ficin would inhibit the graft-host immune reaction to the allograft. After treatment with ethanol, the basal laminar scaffold of the Schwann cell remained intact and there was satisfactory axonal regeneration. The results after additional treatment with ether or ficin did not achieve such good results. Preservation of the basal lamina is considered to be the essential factor in allowing neural regeneration in these circumstances.

Animals↗
PubMed1990

Three-dimensional organization of the collagen fibrils in the rat sciatic nerve as revealed by transmission- and scanning electron microscopy.

The organization of collagen fibrils in the rat sciatic nerve was studied by scanning electron microscopy after digestion of cellular elements by sodium hydroxide treatment, and by conventional transmission electron microscopy. The epineurium consisted mainly of thick bundles of collagen fibrils measuring about 10-20 microns in width; they were wavy and ran slightly obliquely to the nerve axis. Between these collagen bundles, a very coarse meshwork of randomly oriented collagen fibrils was present. In the perineurium, collagen fibrils occupied the interspaces between the concentrically arranged perineurial cells; in each interspace, they formed a sheet of characteristic lacework elaborately interwoven by thin (about 3 microns or less in width) bundles of collagen fibrils. In the subperineurial region, there was a distinct sheet of densely woven collagen fibrils between the perineurium and underlying endoneurial fibroblasts. In the endoneurium, collagen fibrils surrounded individual nerve fibers in two layers as scaffolds: the inner layer was made up of a delicate meshwork of very fine collagen fibrils, and the outer one consisted of longitudinally oriented bundles of about 1-3 microns in width. The collagen fibril arrangement described above may protect the nerve fibers against external forces.

Ammonium Hydroxide↗
PubMed1990

Nerve regeneration through the cryoinjured allogeneic nerve graft in the rabbit.

To examine whether the 3-4-cm-long allogeneic basal lamina tubes of Schwann cells serve as conduits for regenerating axons in rabbits, allogeneic saphenous nerve, which had been predenervated and pretreated by freezing, were transplanted from Japanese White rabbits (JW) to New Zealand White rabbits (NW). Animals were killed 1, 2, 6, 8, and 14 weeks after transplantation, and the cytology at the mid-portion of the grafts was examined by electron microscopy. The distal portion of the host saphenous nerves was also examined 14 weeks after grafting. Myelin sheath debris was phagocytosed by macrophages, while the basal lamina of Schwann cells were left intact in the form of tubes. Regenerating axons were first found in such basal lamina tubes 2 weeks after grafting, and gradually increased in number. Host Schwann cells accompanied the regenerating axons behind their growing tips, separating them into individual fibers and forming thin myelin sheaths on thick axons by 6 weeks after grafting. Regenerating nerves were divided into small compartments by new perineurial cells. Newly formed blood vessels were situated outside the compartment 8 weeks after grafting. The percentage of myelinated fibers in the regenerating nerves was roughly 10% at 8 weeks and 30% at 14 weeks after grafting. The diameter of the regenerating axons, both myelinated and unmyelinated, was less than that of normal axons at all the stages examined. Numerous regenerating axons, some of which were fully myelinated, were found at the site 10 mm distal to the distal end of the graft 14 weeks after grafting.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1990

Allogeneic nerve grafts in the rat, with special reference to the role of Schwann cell basal laminae in nerve regeneration.

The role of basal laminae as conduits for regenerating axons in an allogeneic graft was examined by transplanting a 3 cm long segment of the sciatic nerve from the Brown Norway to the Fischer 344 strain of rat. These strains are not histocompatible with each other. In order to compare the nerve regeneration in variously treated grafts, three different types of graft were employed: non-treated (NT), predenervated (PD), and predenervated plus freeze-treated (PDC) grafts. The cytology of nerve regeneration through these grafts was examined by electron microscopy at four, seven, 14, 30 and 60 days after grafting. In the PDC graft, in which Schwann cells were dead on grafting, basal laminae were well preserved in the form of tubes after Schwann cells and myelin sheaths had been removed at seven days after grafting. Regenerating axons accompanied by immature host Schwann cells grew out through such basal lamina tubes in the same fashion as observed in our previous studies. By day 14, axons extended as far as the middle of the graft. In the proximal part they were separated into individual fibres and even thinly myelinated by Schwann cells. On the other hand, in the NT and PD grafts in which Schwann cells were alive on grafting, most Schwann cells and myelin sheaths appeared to undergo autolytic degeneration by day 14, while Schwann cell basal laminae were left almost intact in the form of tubes. A few regenerating axons were seen associated with Schwann cells in the proximal portion by day seven. It is probable that host Schwann cells moved into the graft after donor cells had been degraded. Schwann cell basal laminae tended to be damaged at the site of extensive lymphoid cell infiltration. By day 30, regenerating axons had arrived at the distal end of the graft in all three types of graft: in the PDC graft thick axons were fully myelinated, whereas in the PD graft they were only occasionally myelinated and in the NT graft most axons were still surrounded by common Schwann cells. By 60 days after grafting, regenerating axons were well myelinated in the host nerve as observed 1 cm distal to the apposition site in all the three types of graft. These findings show that Schwann cell basal laminae can serve as pathways (most efficiently in the PDC graft) for regenerating axons in a 3 cm long allograft in the rat.

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PubMed1990

Effacement and regeneration of tactile lamellar corpuscles of rat after postnatal nerve crush.

The development of Meissner-like lamellar corpuscles was studied in rat toe pads under normal conditions and after crushing the sciatic nerve in 1- to 15-day-old animals. During normal development, rat lamellar corpuscles begin to differentiate first by postnatal day 8. By this time, sensory axons have grown up to the apex of dermal papillae and form axon terminals beneath epidermis. The terminals are ensheathed by lamellar cells derived from Schwann cells. First thin lamellae are formed around the terminals 8-12 days after birth, and the number of lamellar layers increases until the corpuscles become structurally mature by 20 days after birth. A mature corpuscle consists of two or more terminals, each surrounded by approximately 10 lamellae, all components being enclosed by an incomplete capsule. No lamellar corpuscles develop in toe pads after crushing the sciatic nerve in newborn rats, and only occasional corpuscles regenerate after nerve crush at 5 days of age. The corpuscles fail to develop because dermal papillae remain permanently denervated after crushing the nerve early postnatally. After nerve crush in 10-day-old rats, lamellar corpuscles regenerate by 1 month after the operation, but they remain underdeveloped: their number and size are smaller than normal even 1 year after injury, and their terminals are encircled only by 1-3 lamellar layers. After nerve crush in 15-day-old rats, the corpuscles recover upon reinnervation and their size and lamellation become almost normal.

Aging↗
PubMed1990

Peripheral nerve regeneration.

Schwann cell basal laminae were demonstrated to serve as efficient conduits for the growth of regenerating axons in frozen nerve grafts, and in in situ freezing experiments. Regenerating axonal sprouts usually emanated from the first node of Ranvier proximal to the site of damage, and grew out along the inner surface of the basal lamina. Early growth cones contained numerous clear vesicles of about 50 nm in diameter.

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PubMed1990

The filamentous meshwork in the Schwann cell basement membrane as revealed by transmission and scanning electron microscopy.

The three-dimensional architecture of filamentous components in the lamina densa of the Schwann cell basement membrane was studied in the mouse sciatic nerve by transmission and scanning electron microscopy after osmium-maceration treatment, and also by conventional electron microscopy. In conventionally prepared specimens, the lamina densa of the basement membrane was the most electron-dense, showing up as a felt-like layer 20-30 nm thickness. The interstitial surface of this layer had a spongy appearance with numerous shallow pits. Maceration of the specimens with 0.1% OsO4 for 2-4 days effectively removed amorphous, non-filamentous components from the basement membrane, thus exposing fine filamentous structures embedded in the lamina densa; these were about 10-15 nm in diameter and elaborately interwoven and/or connected with each other to form the framework of the lamina densa. Occasionally, some of them appeared to twine around adjoining collagen fibrils. The nature of these filamentous structures is discussed in terms of the chemical components of the basement membrane.

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PubMed1990

Regenerating axons and their growth cones observed by scanning electron microscopy.

A predenervated sciatic nerve segment, which had been treated by repeated freezing and thawing to kill Schwann cells, was grafted to the original sciatic nerve in the rat. Three to five days later, the graft was chemically fixed and treated by KOH-collagenase digestion, a treatment which selectively removes almost all non-cellular elements including the collagen fibrils and basal laminae from the tissue, thus making it possible to observe regenerating axons by scanning electron microscopy. Debris of degraded Schwann cells and myelin sheaths remained in the form of "columns", and several thick (2-3 microns in diameter) and thin (less than 1 micron in diameter) axons ran singly or in bundles on such "cell debris columns." Thick axons have an almost straight contour, while there were various swellings at intervals along the thin axons. In most cases, the growing tips of regenerating axons were swollen as growth cones ranging from 2 microns to 5 microns in diameter. Growth cones exhibited fusiform to polygonal variations in structure and had only a few filopodial processes on the surface.

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PubMed1989

Membrane relationships in murine Meissner corpuscles: cytology of freeze-substituted tissue.

Mechanoreceptive sensory corpuscles (murine Meissner corpuscles) in the toe pad skin of mice, consisting of axon terminals and lamellar cells, were studied following freeze-substitution in order to clarify the plasma membrane relationships between axon terminals and lamellar cells. Tissue preservation of corpuscles was excellent when the corpuscle was located within 10 microns from the contact surface with the precooled metal block. The axolemmata appeared more electron-opaque than did plasma membranes of lamellar cells. The inner leaflet of the unit membranes was thicker than the outer leaflet in the axolemma, and the contour of cell plasma membranes was relatively smooth and straight. Characteristic focal or regional approximations of plasma membranes were noted between the axon and abutting lamellae. Such membrane appositions resembled gap junctions, although no gap junctions were found between the axon and lamellae in chemically fixed materials. Similar gap junction-like close appositions of plasma membranes also were found between neighboring lamellae. These approximations occurred more frequently than typical gap junctions seen in chemically fixed materials. These findings indicate that there may be a relationship of the plasma membranes in the axon terminals and in abutting lamellae as well as between neighboring lamellae that have not been identified as yet in conventional chemically fixed material. Another striking finding was that basal laminae on lamellar cells exhibited the same electron opacity as the surrounding connective tissue matrix and thus the two are indistinguishable from one another. Furthermore, the lamina lucida was not evident, and basal lamina material was directly contiguous with the plasma membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1989

Demyelination and remyelination in the dorsal funiculus of the rat spinal cord after heat injury.

Part of the dorsal funiculus of the adult male rat (Wistar) spinal cord was treated for 1 h at the thoracolumbar level by running hot water, at approximately 48-50 degrees C, through a polyethylene tube 2 mm in diameter in contact with the dura. Animals were fixed 1 day to 4 weeks later and the spinal cords were examined by light and electron microscopy. The affected area in the dorsal funiculus was approximately 1 mm long and less than 1 mm wide at the dorsal surface, and varied from 0.4 to 0.7 mm in depth. Within 3 days after treatment, almost all the myelin sheaths in the affected area were degraded, leaving the axons denuded, and at the same time astrocyte endfeet at the glial limiting membrane were swollen and partly destroyed. Almost all the denuded axons remained intact, exhibiting no noticeable morphological changes. There was evidence of a moderate vasogenic oedema, but minimal signs of haemorrhage in the lesion. Seven days after treatment, many immature Schwann cells but no oligodendrocytes were found between the denuded axons. By 2 weeks many of the denuded axons were remyelinated, and by 4 weeks almost all of those axons located near the pial and perivascular surfaces had been remyelinated by Schwann cells, while most of those located in the deep and marginal zones bordering the adjoining intact areas were remyelinated by oligodendrocytes. Longitudinal sections revealed that at nodes of Ranvier PNS-type myelin sheaths were apposed by either intact or newly formed CNS-type myelin sheaths. A typical glial limiting membrane was not reformed beneath the pial surface, but an inconspicuous one was found between the PNS- and CNS-type fibre areas.

Animals↗
PubMed1989

Two circulatory routes within the human corpus cavernosum penis: a scanning electron microscopic study of corrosion casts.

The microvascular architecture of the human corpus cavernosum penis was studied by scanning electron microscopy of vascular corrosion casts. The corpus cavernosum was supplied by the penile deep artery. It gave off branches to become either arteries distributed within the corpus cavernosum or those directly supplying the corpus spongiosum urethrae. The former arteries further divided into small arteries which fell into two categories: 1) arteries breaking up into capillaries, and 2) arteries draining directly into the cavernous sinuses. The capillaries were collected into venular networks just beneath the tunica albuginea (the subalbugineal venular plexus), while the cavernous sinuses were collected into venules at the periphery of the corpus cavernosum. These postcavernous venules also received venules from the subalbugineal venular plexus, and left the corpus cavernosum. Thus, two circulatory routes are evident within the corpus cavernosum. These findings suggested that the penile erectile cycle is controlled by hemodynamic changes between these two routes within the corpus cavernosum.

Adult↗
PubMed1989

Nerve regeneration in the dorsal funiculus of the rat spinal cord: a light and electron microscopic study.

In an attempt to identify regenerating axons in the central nervous system, a partial transection of the dorsal funiculus in the rat spinal cord was carried out with a pair of microdissection scissors, and a nylon thread loop was inserted into the lesion to demarcate the severed tissue. Nerve regeneration through the demarcated lesion was observed 4-20 days after the operation by light and electron microscopy. In the early stage, many naked axons appeared from the caudal part of the lesion, and some of these further extended into the demarcated space. They contained an accumulation of mitochondria, smooth-surfaced endoplasmic reticulum and vesicles in the axoplasm; this axoplasmic feature indicated that they were regenerating axons. They gradually increased in number, and took highly irregular courses exhibiting various fluctuations in diameter throughout their lengths. Immature Schwann cells as well as glial cells including oligodendrocytes and astrocytes appeared in close association with these regenerating axons. Oligodendrocytes eventually formed thin myelin sheaths. On the other hand, naked axons were present deflecting outside the thread loop; they showed no axoplasmic characteristics as described above. These axons could be regarded as uninjured ones merely undergoing demyelination due to the surgery. Thus, regenerating axons were clearly distinguished from merely demyelinated ones, and some of them were shown to grow through the traumatic lesion in the dorsal funiculus of the rat spinal cord.

Animals↗
PubMed1989

Regeneration in the rat optic nerve after cold injury.

In order to examine nerve regeneration under conditions in which the basal laminae of the glial limiting membranes (GLM) and blood vessels were preserved intact, the intraorbital segment of adult rat optic nerve was frozen locally. During the next 3 months, degenerative and regenerative changes in axons and glial cells were observed by light and electron microscopy. On the day after treatment, all the myelinated and unmyelinated axons in the central zone of the lesion were damaged. The astrocyte endfeet of the GLM as well as the blood vessels were extensively disrupted, while their basal laminae were preserved apparently intact as a continuous sheet. Three days after treatment, regenerating axons appeared in the central zone of the lesion. They contained various numbers of clear and dense-cored vesicles as well as some smooth endoplasmic reticulum. The regenerating axons gradually increased in number, especially beneath the pial and perivascular surfaces of the lesion, where an abundance of regenerating axons was found 3 months after treatment. A few of these axons were abnormally remyelinated by oligodendrocytes. In addition to this axonal regeneration through the intraoptic nerve compartment, fine regenerating axons were seen growing out through GLM into the pial connective tissue 3 weeks after treatment. Astrocyte endfeet of the GLM became irregular in contour, protruding in a fern-leaf fashion into the pial connective tissue. Fine naked axons grew out through these protrusions and subsequently increased in number, vigorously growing in large bundles both proximally and distally along blood vessels in the pial connective tissue. Bundles of regenerating axons extended as much as 1.5 mm from the site of the lesion 3 months after surgery. These bundles were covered by thin processes of pial or arachnoidal non-neuronal cells, and the regenerating axons remained unmyelinated. The above findings indicate that under well-nourished conditions, adult mammalian optic nerve exhibits considerable regenerative ability.

Animals↗
PubMed1988

Tentative identification of arterial baroreceptors associated with arteriovenous anastomoses.

Nerve endings of the trigeminal nerve were examined in the lip, nostril, upper jaw and supraorbital skin of cat by the horseradish peroxidase (HRP) tracing method. Wheatgerm agglutinin-HRP (WGA-HRP) as injected into the spinal trigeminal nucleus was transported transganglionically to nerve endings. The present study deals with presumptive baroreceptive nerve endings found on arteriovenous anastomoses and on some other large arteries. By light microscopy HRP-labeled, complexly arborized nerve endings were found on the walls of arteries located deep in the subcutaneous tissue of the lip and nostril. These arteries were identified in serial sections to be an arterial segment of an arteriovenous anastomosis. By electron microscopy characteristic nerve endings were located in the adventitia and partly extended into the adjacent connective tissue of the arterial wall. These terminals had no connective tissue capsule. Axon terminals were somewhat enlarged (1-2 microns in diameter) and extended through bundles of collagen fibrils. The terminals contained an abundance of mitochondria and some vesicles. Axon terminals were typically covered by thin Schwann cell processes, but parts of the axolemma were sometimes devoid of such Schwann cell coverings, being invested only by basal laminae. Cell bodies of Schwann cells were located apart from axons. These light and electron microscopic features of the endings resembled those of other well-defined baroreceptors reported in the carotid sinus, aortic arch and endocardium, as well as of Ruffini terminals and Golgi tendon organs, suggesting that they would be baroreceptors of arteriovenous anastomosis. In addition HRP-labeled single nerve fibers with varicosities were found in the walls of some large arteries in the facial skin. By electron microscopy, such a HRP-positive nerve fiber contained some mitochondria and vesicles in varicosities and coursed with a bundle of HRP-negative fine fibers in the adventitia of arteries. These HRP-labeled single fibers were considered to be sensory derived from trigeminal nerves.

Animals↗
PubMed1988

A re-evaluation of the cytology of cat Pacinian corpuscles. I. The inner core and clefts.

The ultrastructure of cat mesenteric Pacinian corpuscles in cross and longitudinal sections has been examined. The terminal ends of lamellar cells of the inner core have been identified in longitudinal sections through the proximal portion of the inner core. These terminal bulbous expansions contain characteristics concentric membranes of rough endoplasmic reticulum and in some cases masses of oval membranous inclusions. The central axon as seen in cross section is oval in profile, having X-(short) and Y-(long) axes, and each axonal face is characterized by specializations of the axolemma. At the X-axis, the inner lamellae of the inner core tightly abut a smooth axolemma, with no intervening connective tissue matrix, in a manner reminiscent of a neuroepithelium. The axolemma of the Y-axis has numerous axonal spines (microspikes) that project into the cleft in the inner core. The extent of the axolemma having axonal spines can only be appreciated in longitudinal sections. The clefts contain a specialized connective tissue with elastic and collagen fibrils. The connective tissue compartment of fibers and matrix separating individual inner core lamellae is unique, in that it contains extremely thin collagen fibrils measuring approximately 15 nm in diameter. The diameter of collagen fibrils increases as the cleft is approached. Here the fibrils resemble typical endoneural collagen.

Animals↗
PubMed1988

A re-evaluation of the cytology of cat Pacinian corpuscles II. The extreme tip of the axon.

The present report is the second of two studies re-evaluating the cytological characteristics of Pacinian corpuscles. The extreme tip of the axon of a Pacinian corpuscle has been identified and is quite different from the previously described ultraterminal region. The latter is the site where the inner core lamellae begin to terminate and is characterized by a smooth axolemma. The extreme tip lacks inner core lamellae directly abutting the axolemma and is instead characterized by the presence of many axonal spines projecting into a matrix of basal lamina-like material. The extreme tip of the axon thus resembles the organization of the axolemma facing the clefts of the inner core. The axonal spines at the cleft and extreme tip are proposed as a site of restricted current flow due to the tight apposition of inner core lamellae to the axolemma of X-axis. The hemi-inner cores thus could restrict current flow to the cleft. These anatomical specializations could represent both a source and a sink for K+ ions during mechano-electric transduction and account in part for the exquisite sensitivity of Pacinian corpuscles to complex pressure waves.

Animals↗
PubMed1988

The structure and function of cutaneous sensory receptors.

The present review of cutaneous sensory receptors begins with a consideration of free nerve endings (FNEs) that can be considered as sensory terminals evidencing the least structural specialization of the axon and associated cells. Using the criteria established by Kruger et al (1981), FNEs of both A delta and C fibers can be identified on the basis of ultrastructural characteristics that include an intimate relationship between axons and the associated epithelium, the lack of a complete Schwann cell investment, the accumulation of numerous vesicles and other cytoplasmic organelles, and for A delta terminals a 1:1 relationship between axon and investing Schwann cell. Using these criteria, the so-called genital end bulbs of the human glans penis are merely a skein of FNEs based on the ultrastructural study of Halata and Munger (1986). Hair follicles of most species studied to date (the exception being the rabbit and to some extent the guinea pig) are multiply innervated with lanceolate, Ruffini and FNEs. The lanceolate terminals are the rapidly adapting terminals that are numerous in guard hairs. Ruffini terminals of hairs resemble those of the periodontal ligament or joint capsules and both are remarkably similar to Golgi tendon organs in terms of ultrastructural characteristics. The key ultrastructural characteristic is the encircling of collagen bundles by axons and associated Schwann and connective tissue cells. Axons frequently enter the epidermis either to terminate as FNEs or become associated with Merkel cells in glabrous skin at the base of the papillary ridges or in clusters of Merkel cells in hairy skin in touch domes or Haarscheiben. Merkel cells have clusters of apparent secretory granules polarized toward the axon and the axon is typically a slowly adapting mechanoreceptor. The function of the granules is not known. Pacinian corpuscles are the largest of the corpuscular receptors of the dermis and are characterized by an elaborate inner core of stacks of numerous thin lamellae arranged in a bilaterally symmetrical manner. Based on the fact that the lamellae are coupled with gap junctions and the outer core lamellae isolated by numerous tight junctions, the authors have proposed that the unique ionic environment may be in part responsible for the remarkable sensitivity of Pacinian corpuscles (Munger and Ide, 1987). Meissner corpuscles are a typical corpuscular receptor of murine (Ide, 1976, 1977), marsupial and primate glabrous skin (Munger, 1971). The axons typically weave back and forth between stacks of lamellae.(ABSTRACT TRUNCATED AT 400 WORDS)

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