Definition and diagnosis of small fiber neuropathy: consensus from the Peripheral Neuropathy Scientific Department of the Brazilian Academy of Neurology / Definição e diagnóstico de neuropatia de fibras finas: consenso do Departamento Científico de Neuropatias Periféricas da Academia Brasileira de Neurologia

ABSTRACT The aim of this study was to describe the results of a Brazilian Consensus on Small Fiber Neuropathy (SFN). Fifteen neurologists (members of the Brazilian Academy of Neurology) reviewed a preliminary draft. Eleven panelists got together in the city of Fortaleza to discuss and finish the text for the manuscript submission. Small fiber neuropathy can be defined as a subtype of neuropathy characterized by selective involvement of unmyelinated or thinly myelinated sensory fibers. Its clinical picture includes both negative and positive manifestations: sensory (pain/dysesthesias/pruritus) or combined sensory and autonomic complaints, associated with an almost entirely normal neurological examination. Standard electromyography is normal. A growing list of medical conditions is associated with SFN. The classification of SFN may also serve as a useful terminology to uncover minor discrepancies in the normal values from different neurophysiology laboratories. Several techniques may disclose sensory and/or autonomic impairment. Further studies are necessary to refine these techniques and develop specific therapies.

RESUMO O objetivo deste estudo é descrever os resultados de um Consenso Brasileiro sobre Neuropatia de Fibras Finas (NFF). Quinze neurologistas (membros da Academia Brasileira de Neurologia) revisaram uma versão preliminar do artigo. Onze panelistas se reuniram na cidade de Fortaleza para discutir e terminar o texto para a submissão do manuscrito. NFF pode ser definida como um subtipo de neuropatia caracterizada pelo envolvimento seletivo de fibras sensitivas amielínicas ou pouco mielinizadas. Seu quadro clínico inclui manifestações negativas e positivas: sensitivas (dor/disestesias/prurido) ou queixas sensitivas e autonômicas combinadas, associadas a exame neurológico quase totalmente normal. A eletromiografia convencional é normal. Uma lista crescente de condições médicas causa NFF. NFF também pode servir como uma terminologia útil para referenciar pequenas discrepâncias nos valores normais de diferentes laboratórios de neurofisiologia. Diferentes técnicas podem evidenciar anormalidades sensitivas e/ou autonômicas. São necessários mais estudos para refiná-las e para o desenvolvimento de terapias específicas.

The Effects of Soybean Diet on the Diabetic Neuropathy in the Rats / 대한해부학회지

Neuropathy is a serious and disabling complication that contributes to increased morbidity and mortality in diabetic patients. There is progressive distal to proximal axonal atrophy that ultimately leads to Wallerian degeneration. This study was performed to identify the effect of soy bean on diabetic neuropathy using morphometry. Male Sprague-Dawley rats were grouped into control, diabetic with red chow diet and diabetic with soy bean diet. The myelinated nerve fibers were counted and fiber size distributions were evaluated in each group at 4 and 8 weeks, respectively. Diabetic neuropathy didn't develop in streptozotocin-induced diabetic rats at four weeks. At 8 weeks, the myelinated nerve fiber in diabetic with soy bean diet was larger in number than that in diabetic to which did not be administered insulin. The number of myelinated nerve fiber was not different between diabetic group with insulin and without insulin. Mean myelinated nerve fiber size was smaller in diabetic with soy bean diet than diabetic with red chow diet and control. Histogram of fiber size distribution was shifted to left in diabetic with red chow and soy bean diet groups compared to control. Light and electron microscopic findings showed marked degeneration of nerve fibers in diabetic with red chow diet but preservation in diabetic with soy bean diet. The level of glucose and HbA1c was lower in diabetic with soy bean diet than red chow diet. Soy bean could be effective in the protection of neuropathy induced by diabetes mellitus.

Electron Microscopic Study of the Corneal Nerve by Flat Serial Section

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.

Morphological Changes of Cerebrum in Rabbits Exposed to Microwaves

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.