The author measured the severity of brain damage of 36 rabbits irradiated 2.45 GHz microwave for 10 minutes, 20 minutes and 30 minutes, respectively. Electromicroscopic and light microscopic findings of just after, 1 weeks, 2 weeks and 4 weeks after irradiated brain were compared in each time. Swelling and vacualization of nerve cell and mitochondria were noted. Also these changes tend to increased severity along amount of radiation, but revealed reversible changes with time. Myelinated and unmyelinated nerve fibers were examined as same manner. These nerve fibers also revealed swelling and vascuolization, these findings also tend to increase severity with irradiation power and more prominent at unmyelinated nerve fibers. Reversability of these findings after each time period were more prominent in myelinated nerve fibers than unmyelinated nerve fibers.
Brain ; Cerebrum* ; Microwaves* ; Mitochondria ; Myelin Sheath ; Nerve Fibers ; Nerve Fibers, Myelinated ; Nerve Fibers, Unmyelinated ; Neurons ; Rabbits*

PURPOSE: We evaluated the ocular findings associated with peripapillary myelinated nerve fibers of 3 clock hours or more in 15 patients. METHODS: Ophthalmologic examination was performed in 15 patients with peripapillary myelinated nerve fibers of 3 clock hours or more. Twelve younger patients who wanted occlusion therapy were enrolled into a therapeutic trial with spectacle correction and occlusion for amblyopia. RESULTS: Thirteen out of the 15 patients presented with varying degrees of anisomyopia and amblyopia. The final visual acuities of the 12 younger patients with spectacle correction and occlusion for amblyopia were 0.5 or better in 5, between 0.1 and 0.5 in 4, and worse than 0.1 in 3. Two patients showed no ocular abnormalities except negligible refractive errors. Five out of 13 patients with amblyopia showed constant exotropia and one showed intermittent exotropia in the eyes with myelinated nerve fibers. CONCLUSIONS: Most of the patients with peripapillary myelinated nerve fibers of 3 clock hours or more showed anisomyopia and amblyopia. As some patients responded to spectacle correction and occlusion therapy for amblyopia, aggressive amblyopia therapy should be considered even in patients with myelinated nerve fibers.
Amblyopia ; Exotropia ; Humans ; Myelin Sheath* ; Nerve Fibers, Myelinated* ; Refractive Errors ; Visual Acuity

Effects of aconitine on the retina and optic nerve were studied in rabbits by means of visual evoked potential(VEP), electroretinogram(ERG), and electron microscopy. Aconitine(0.4mg/kg) was administered intra peritoneally. The effects of aconitine were observed at 1 day, 3 days, 1 week, 2 weeks, 3 weeks, and 3 months after injection, respectively. The amplitude of VEP was decreased significantly at 1 and 2 weeks after injection. However ERG b-wave, c-wave, and the latency of VEP were not significantly changed during the experimental periods. Histopathological changes in the optic nerve and visual streak were characterized by disorganization of the lamellar structures of the myelin sheath, diffuse mitochondrial swelling, and vacuolization in the myelinated nerve fibers, which were increased in degree with time. No perceptible change in the retina including retinal pigment epithelium was observed in the experimental periods. Schwann cells and unmyelinated nerve fibers appeared unaffected, except for mild swelling of mitochondria. Above mentioned electrophysiological and electron microscopic studies indicated that the effect of aconitine on the rabbit eye was toxic myelo-optic neuropathy.
Aconitine* ; Microscopy, Electron ; Mitochondria ; Mitochondrial Swelling ; Myelin Sheath ; Nerve Fibers, Myelinated ; Nerve Fibers, Unmyelinated ; Optic Nerve ; Optic Nerve Diseases* ; Rabbits ; Retina ; Retinal Pigment Epithelium ; Schwann Cells

PURPOSE: We wanted to compare the nerve regeneration of inside-out vein grafts, muscle-filled inside-out vein grafts and fat-interposed inside-out vein grafts to repair the 10 mm sciatic nerve defects in rats. MATERIALS AND METHODS: We performed inside-out vein grafts, muscle-filled inside-out vein grafts and fat-interposed inside-out vein grafts to repair the 10 mm sciatic nerve defects in 45 rats. Histological examinations (the numbers and diameters of myelinated nerve fibers), electrophysiologic testing (Compound Muscle Action Potential (CMAP) and Nerve Conduction Velocity (NCV)) examinations were performed 3 months after surgery. RESULTS: Quantitative analysis of myelinated nerve fibers showed that total number of nerve fibers was significantly greater in group 1 or 3 than that in group 2. There were statistical differences in the three groups for the fiber diameters of the myelinated fibers. Electrophysiologic examination showed that both CMAP and NCV were significantly greater in group 3 than that in group 2 and there was no statistical difference between in groups 1 and 3. CONCLUSION: This study shows that fat-interposed inside-out vein grafts have excellent axonal regeneration as compared to that of inside-out vein grafts or muscle-filled inside-out vein grafts to repair 10 mm sciatic nerve defects in rat. Therefore fat-interposed inside-out vein grafts are an effective method to accelerate the early axonal regeneration for repairing nerve defects.
Action Potentials ; Animals ; Axons ; Muscles ; Myelin Sheath ; Nerve Fibers ; Nerve Fibers, Myelinated ; Nerve Regeneration ; Neural Conduction ; Rats ; Regeneration ; Sciatic Nerve ; Transplants ; Veins

A case of Isaacs syndrome with Trousseau s phenomenon wac studied electrophysiologically and histologically. The needle electromyography showed typical neuromyotonic discharges of spontaneous recurrent high-frequency(150-300Hz) bursts of motor unit activity with 0.5-3 second of duration and typical waning pattern This discharge was not suppressed by brachial plexus block Motor and sensory nerve conduction velocities were either s!ightly below or in the lower range of normal. In repetitive nerve stimulation test a decremental response to low rate stimulation was noted in abductor digiti quinti muscle. On sural nerve biopsy, there was a decrease in the number of myelinated nerve fibers showing both axonal and myelin degeneration The clinical and electrophysiologic abnormalities improved considerably after treatment with phenytoin.
Axons ; Biopsy ; Brachial Plexus ; Electromyography ; Isaacs Syndrome* ; Myelin Sheath ; Needles ; Nerve Fibers, Myelinated ; Neural Conduction ; Phenytoin ; Sural Nerve

Spinal Cord contusions in cats were produced experimentally by impact injuries to the surgically exposed cord at the second lumbar vertebral level. As a step in the investigation of the possible effect of spinal cord trauma on biochemical and ultrastructural changes in the injured cord, activities of lipid peroxidation were measured in the frozen-dried sample of the spinal cord and the fine structure of the myelinated nerve fiber in the white matter were observed before and after the cord injury. An increase of lipid peroxidation level was found as early as 30 minutes after the injury and the highest concentration was reached at 4 hours of injury. Fine structures of the myelinated nerve fibers were changed progressively with the lapse of time after the injury. By 1 hour after the contusion the myelinated nerve fibers showed moderately enlarged periaxonal space, attenuation and disarray of the myelin sheaths. By 4 hour after the contusion, there appeared disarray of the myelin sheaths, greatly enlarged periaxonal space and irregulary contoured axons. The effect of naloxone of the lipid peroxidation and fine ultrastructure of the myelinated nerve fibers were studied, and the results of this study suggested that naloxone have a beneficial effect on the change in lipid peroxidation and the preservation of the myelinated nerve fibers after injury.
Animals ; Axons ; Cats ; Contusions ; Lipid Peroxidation* ; Myelin Sheath* ; Naloxone* ; Nerve Fibers, Myelinated ; Spinal Cord Injuries ; Spinal Cord*

PURPOSE: To investigate the cellular changes and cellular characteristics of myelinated nerve fiber, unmyelinated nerve fiber and Schwann cell under the culture conditions of the explant of the long ciliary nerve. METHODS: The ciliary nerve was obtained from the eyecup after removal of the cornea and intraocular contents following the division of the eyeball at the limbal zone. The explant of the ciliary nerve was cultured with DMEM medium containing nerve growth factor in an incubator with a 5% CO2 atmosphere. The cultured ciliary nerve was examined with phase contrast microscopy at 35 days after culture and stained in the culture dish with 1% methylene blue. The cultured ciliary nerve was also examined with transmission electron microscope. RESULTS: The phase contrast microscopy showed monolayered Schwann cells and cells with thin cytoplasmic processes. The ultrastructure showed myelinated nerve fiber, unmyelinated nerve fiber and Schwann cells entrapped in the nerve fiber. The axoplasm of the myelinated nerve fiber showed the degeneration of microorganelles whereas the unmyelinated nerve fiber showed well preserved microorganelles such as neurofilaments and mitochondria within the axoplasm. CONCLUSIONS: These findings suggest that the axoplasm of the unmyelinated nerve fiber under these culture conditions is relatively better preserved than that of the myelinated nerve fiber probably due to the absence of the myelin sheath. Further study will be required to investigate whether the myelin sheath of the ciliary nerve derived from peripheral neuropathy may affect the functional change of the anterior segment of the eye.
Atmosphere ; Cornea ; Cytoplasm ; Incubators ; Methylene Blue ; Microscopy, Phase-Contrast ; Mitochondria ; Myelin Sheath ; Nerve Fibers ; Nerve Fibers, Myelinated ; Nerve Fibers, Unmyelinated ; Nerve Growth Factor ; Peripheral Nervous System Diseases ; Schwann Cells

PURPOSE: This study was performed to describe the ultrastructure of stromal nerve fibers in central, mid-peripheral, and peripheral parts of the human cornea by flat serial corneal section. METHODS: Seven samples from fresh normal cornea, derived from eyes with retinoblastoma and eyes from eye bank, were processed for transmission electron microscopic examinations. Flat serial sections reaching from mid-epithelium to the anterior stroma were observed. RESULTS: The myelinated and unmyelinated nerve fibers are alternately arranged and run parallel to the stromal collagen fibers at the periphery of the cornea. The main difference between the limbal and the central cornea is the presence of myelinated nerve fibers in the anterior peripheral stroma. The diameter of the unmyelinated nerve fiber measures between 0.25 and 0.63 micrometer in size. The corneal nerve fibers contain vesicles, mitochondria, and glycogen particles. The peripheral nerve fibers contain both clear and dense vesicles. The nerve fiber is separated by an interval of 0.3 micrometer from the cytoplasmic wall of keratocyte at the center of the cornea. CONCLUSIONS: The majority of the corneal nerve fibers can be classified as C-fibers due to their size. The presence of both clear and dense vesicles within the cytoplasm of the periphery of the cornea suggest that a small portion in the peripheral corneal nerve may be originated from the sympathetic nervous system. A close vicinity between the nerve fibers and keratocyte supports that nerve fibers might modulate the release of growth factors in the regulation of stromal and epithelial metabolism.
Collagen ; Cornea ; Cytoplasm ; Eye Banks ; Glycogen ; Humans ; Intercellular Signaling Peptides and Proteins ; Metabolism ; Mitochondria ; Myelin Sheath ; Nerve Fibers ; Nerve Fibers, Myelinated ; Nerve Fibers, Unmyelinated ; Peripheral Nerves ; Retinoblastoma ; Sympathetic Nervous System

Toxic effects of Aconiti tuber, an important ingredient of Chinese medicinal preparation, have been encountered clinically. The chief bioactive and toxic constituent is the alkaloid aconitine. In this study histopathologic changes in the fine structures of rabbit eye by intravenously administered aconitine were examined with light and electron microscopes. The initial and most characteristic features observed in the histopathologic study were degenerative changes in the myelinated nerve fiber layer. So the effects of aconitine on the rabbit eye were primarily regarded as toxic neuropathy.
Aconitine* ; Asian Continental Ancestry Group ; Humans ; Nerve Fibers, Myelinated

Congenital fibrosis of the extraocular muscle is characterized by the replacement of normal contractile muscles by fibrous tissue in varying degrees. Therefore, the clinical manifestation is dependent upon the degree of fibrous involvement. Brown reported 3 cases of the severe form of congenital fibrosis under the title of "General fibrosis syndrome". It has been known that the inferior rectus muscles are usually most prone to maximal involvement, which causes the eye to assume a hypotropic position with a chin elevation. We experienced two cases of congenital fibrosis of the extraocular muscles; one was a mild form with monocular involvement, and the other was a severe form with absence of all extraocular movement in the both eyes. In the latter, the histopathological examination of the excised tissue by light microscopy revealed that the inferior rectus muscle had a partly degeneration of some muscle fibers, as well as connective tissue proliferation. The lateral rectus muscle was replaced by fibrous tissue and fat cell. We discussed the clinical and histopathological features in the congenital fibrosis of the extraocular muscles.
Adipocytes ; Chin ; Connective Tissue ; Fibrosis* ; Microscopy ; Muscles ; Nerve Fibers, Myelinated