Evolutionary aspects on the origin, distribution and ramifications of the ischiadicus nerve in the giant anteater (Myrmecophaga tridactyla) / Aspectos evolutivos sobre as origens, distribuições e ramificações dos nervos isquiáticos do tamanduá-bandeira (Myrmecophaga tridactyla)

This work aimed to describe the origin, distribution, and ramifications of the ischiadicus nerve in the giant anteater and to provide anatomical data which could explain not only the evolutionary aspects but also provide important information for other related works. For the present study, four specimens were used, prepared by perfusion of 10% formaldehyde solution via the femoral artery, for conservation and dissection. The origin of the right and left ischiadicus nerves in the giant anteater from the ventral ramification of the third lumbar (L3) and the first (S1), second (S2), and third (S3) sacral spinal nerves. These nerves were symmetrical in all animals studied. The distribution and ramification occurred to the superficial, middle, and deep gluteal, gemelli, piriform, quadratus femoris, tensor fasciae latae, caudal crural abductor, cranial and caudal parts of the biceps femoris, adductor, semitendinous, and cranial and caudal parts of the semimembranous muscles. Based on the origins of the ischiadicus nerves, there is a caudal migration in the nerve location in animals in a more recent position on the evolutionary scale due to reconfiguration of the lumbosacral plexus, resulting from the increase in a number of lumbar vertebrae. There is no complete homology of the muscle innervation.(AU)

Objetivou-se descrever as origens, distribuições e ramificações dos nervos isquiáticos no tamanduá-bandeira, disponibilizando, assim, dados anatômicos que possam não só elucidar os aspectos evolutivos como também fornecer informações importantes para áreas afins. Foram utilizados quatro espécimes preparados por meio da perfusão de formaldeído 10% via artéria femoral, para conservação e dissecação. As origens dos nervos isquiáticos direito e esquerdo no tamanduá-bandeira foram provenientes dos ramos ventrais dos nervos espinhais lombares três e sacrais um, dois e três, sendo simétricos em todos os animais estudados. As distribuições e ramificações ocorreram nos músculos glúteos superficial, médio e profundo; gêmeo; piriforme; quadrado femoral; tensor da fáscia lata; abdutor crural caudal; bíceps femoral parte cranial; bíceps femoral parte caudal; adutor; semitendíneo; semimembranáceo parte cranial e semimembranáceo parte caudal. Notou-se que houve uma migração caudal na localização deste nervo nos animais mais recentes na escala evolutiva, devido a uma reconfiguração do plexo lombossacral decorrente do aumento no número de vértebras lombares, não havendo uma homologia total quanto à inervação dos músculos.(AU)

Reaction of peripheral nerves to vascular and bacterial injuries.

Mouse sciatic nerves were subjected to devascularization, M. leprae inoculation, and combined insult of devascularization + footpad inoculation (FPI). Changes were seen in FPI nerves only after eight months, but in cases of combined insult, changes were evident in hours. Both the groups showed initial loss of small myelinated fibres. No proliferation of Schwann cells was in FPI nerves, but in combined insult it was maximum after two weeks. Presence of M. leprae seems to be arresting Schwann cell activity after two weeks. Blood vessels showed increased endothelial cell cytoplasm, basement membrane proliferation and villi formation. These changes seem to be specific of endoneurial blood vessels of leprosy nerves. Increased number of mast cells seems to be specific of devascularized and FPI nerves. Increased number of macrophages expressed low immunity of devascularized nerves. Eosinophils migrated to endoneurium as a result of leakage of axoplasm.

Injertos nerviosos vascularizados: estudio experimental / Vascularized nerve grafts: experimental study

La vascularizacion de los injertos nerviosos es de primordial importancia para la supervivencia del injerto. Preservamos el pediculo proximal en el nervio ciatico del conejo y reparamos un defecto de 4.5 cm. Un modelo experimental de injertos nerviosos vascularizados es presentado como una alternativa para la recuperacion mas rapida de la funcion. Utilizamos 18 conejos, en el lado derecho se efectuo un injerto de 4.5 cm preservando el pediculo vascular, en el lado contralateral se efectuo un injerto de la misma longitud sin preservar ningun pediculo. La neurorrafia se efectuo con nylon 10/0 y microscopio quirurgico. Posteriormente se sacrificaron los animales entre la 5 y la 15 semana del postoperatorio y los nervios se estudiaron con microscopio de luz. El analisis cuantitativo se efectuo en un computador teniendo en cuenta principalmente el espesor de la vaina de mielina. Este experimento demostro que cuando se efectua un injertpo nervioso vascularizado la rata de la maduracion axonal se aumenta hasta 2 veces la rata observada en injertos convencionales. La maduracion de las fibras ocurre de una manera mas rapida y aun utilizando la misma longitud del nervio no se presento ningun caso de necrosis central. En conclusion los resultados son mas favorables en cuanto a regeneracion cuando se utiliza un injerto nervioso vascularizado

Ultrastructure of sciatic nerve of armadillo infected with Mycobacterium leprae.

Ultrastructural observation of sciatic nerves from eight Armadillos were made. Six animals had intravenous inoculation of M. leprae, one had of foot pad, while one had natural leprosy. The available nerves were biopsied at various time sequence ranging from five weeks to twenty four months. Semithin sections did not reveal any neuropathy. Ultrastructurally perineurium was thick and endoneurial collagen was increased. Initially demyelination of non-myelinated fibres was seen in all nerves irrespective of mode of infection. This was followed by demyelination of small myelinated fibres. Active remyelination was predominantly after 17 months. Schwann cell activity was increased and various stages of division were seen. Bacilli were extracellular, intraxonal, in endothelium and in perineurium. Significant observations were on blood vessels. These observations are discussed.