Eros Abrantes Erhart

The brain of the marmoset (Callithrix jacchus)

The gross anatomy and the internal structure of the marmoset ( Callithrix jacchus ) brain are described based on the observations made on the material obtained from 10 adult animals (

Effect of experimental devascularization on peripheral nerves

In order to explore the functional importance of the vasa-nervorum and the nerve natural connective bed, fine nerve devascularizations were performed in ten adult dogs, using a dissecting microscope. 4 to 5 cm of the nerve vascularization and corresponding connective bed were injured. By this procedure it could be demonstrated, 30 days later, motor deficiencies and in the histological serial preparations a distad nerve degeneration, total in some fascicles and partial in others.

The neuroma-like structure of the long-time severed and isolated nerve stumps

The long-time severed and isolated intermediate and distal nerve segments, maintained undisturbed in their connective tissue bed, completely separated from each other and from the proximal stump, are repopulated by nerve-fibres which origin is still unknown. The extremities of such nerve segments present complex nervous nodules capped by fibrous tissue, neuroma-like structures.

Further discussion on the "new-growing" nerve-fibres which repopulate the distal segment of nerves completely separated from the proximal stump for more than six months

Com base em dados experimentais, publicados em trabalhos anteriores, sao apresentados e discutidos, aspectos histologicos que, analisados em sequencia (figs. 1 a 8), sugerem uma possivel via de reorganizacao progressiva com consequente regeneracao de fibras nervosas, nos segmentos intermedio e distal de nervos, completamente separados por transeccao, entre si e do coto proximal, ha mais de seis meses, mas mantidos em seus leitos conectivos naturais.

Brain stem, cerebellum and diencephalon of the marmoset (Callithrix jacchus).

The gross anatomy and the internal structure of the marmoset ( Callithrix jacchus ) brain stem, cerebellum and diencephalon are described based on the observations made on the materia

The ectopic newly-formed nerve fibres which repopulate the long-time denervated and atrophic chick skeletal muscle

1. The whole biventer cervicis muscles of the chick, being innervated by a branch of the dorsal ramus of C, presents structural Deculiarities which recommend it as good skeletal muscle for embryological, anatomical, physiological and pharmacological neuro-muscular investigations. 2. The nerve trunk responsible for the innervation of the distal belly runs completely included within the intermediate tendon; therefore, a tendon transection determines complete denervation and nerve fibre degeneration of the distal belly of the muscle. 3. Long-time experimentally denervated distal bellies (from three up to twelve months) are repopulated by ectopic nerve fibres which must have arisen from a source other than the proximal stump, neighbour nerves or nervi-vasorum. 4. Motor endplates appear in these long-time (eight or more months) denervated biventer cervicis distal bellies. 5. Although atrophic-looking such muscle bellies responded to indirect and to direct electrical stimulation — 1.5 V — by contraction. 6. The long-time denervated distal bellies of the biventer cervicis muscle of the chick, when properly reoperated by cross-grafting suture with the normal contralateral muscle, lost their atrophic appearance and showed to be successfully recovered in about thirty days.

Proper microsurgical nerve suture may impede Wallerian degeneration of completely transected nerves: an electron microscopic study

Electron microscopic findings on the nerve of the biventer cervicis muscle of the chick, which was completely transected and immediately after submitted to an adequate microsurgical nerve suture, confirmed our previous statement that proper microsurgical nerve suture may impede the Wallerian degeneration that normally occurs in the distal segment of a completely transected nerve.

Microsurgical nerve sutures improve rehabilitation and may prevent Wallerian degeneration

A presente modificacao da tecnica de neurorrafia, com emprego da microcirurgia, foi desenvolvida com base em trabalhos experimentais e, tambem, em observacoes clinico-cirurgicas de pacientes portadores de lesoes nervosas perifericas traumaticas, antigas e recentes. A sequencia dos tempos e os cuidados cirurgicos sao descritos; aparecem esquematizados nos quadros 1 e 2. Os resultados experimentais demonstram que suturas de nervos feitas com a tecnica proposta permitem melhor reinervacao dos segmentos corporeos afetados pela desnervacao e podem evitar, tambem, quando feitas logo apos a transeccao do nervo, a total degeneracao walleriana que normalmente ocorre no segmento distal a transeccao. Os resultados obtidos em pacientes que estao sendo operados com esta tecnica sao encorajadores; serao assunto de futuras publicacoes.

Neurofibrillar differentiation in 8- to 14- somites chick embryos

Com o intuito de estudar o inicio da diferenciacao neurofibrilar de neuro-blastos foram preparados cortes seriados de embrioes de galinha impregnados pela prata, modificacao de De Castro do metodo de Cajal. A diferenciacao neurofibrilar inicia-se em fases mais jovens que as descritas na literatura. Em embrioes de galinha de 8 somitos, os primeiros neuroblastos sao encontrados na regiao rombencefalica do tubo neural, ainda aberto, na altura da invaginacao otica. Aos 12 somitos, os neuroblastos comecam a aparecer, tambem, na juncao prosencefalo-mesencefalica, e aos 14 somitos, bem mais diferenciados, apresentam evidente, aumento numerico. Os neuroblastos localizados na juncao prosencefalo-mesencefalica enviam seus axonios caudalmente, constituindo o que parece ser o primordio do fasciculo longitudinal medial. Os neuroblastos rombencefalicos enviam seus axonios ventral, cranial e caudalmente, na espessura das paredes neurais, constituindo, provavelmente, os primordios dos sistemas cordonais e de associacao; por apresentarem-se mais ou menos grupados nos niveis do trigemio, facial e vago, talvez induzam, tambem, a pre-organizacao dos primordios dos nucleos motores dos nervos V, VII e do complexo vagal.

Nerve compression as an essential factor in causing ischaemic and post-ischaemic paraesthesiae

In order to explain why ischaemia produced by compression at the proximal part of the forearm or at the wrist, does not cause sensory disturbances identical to those observed in compression at the upper arm, several experiments were made on ourselves and other subjects. The method used was essentially that of Lewis and Pochin. Circulation was blocked at different levels of the limb by applying the pressure of 200 mm/Hg with a sphygmomanometer cuff; compression of the median, ulnar and tibial nerve trunks was made with the aid of a small cushion under the cuff. We observed always that the nerve compression is an essential factor in causing ischaemic and post-ischaemic paraesthesiae.