Assessment of Nerve Repair Augmented with Adipose-Derived Mast Cells in an Animal Model

We aimed to analyze the involvement of adipose-sourced mast cells in nerve repair. Sixteen Wistar rats underwent complete transection of the sciatic nerves followed by either direct neurorrhaphy or neurorrhaphy and processed abdominal fat. Four animals were used as controls. Specimens were obtained at 4 and 10 weeks and analyzed using luxol fast blue stain, mast cell tryptase and CD34 (for angiogenesis) per microscopic field ×200. When assessed by luxol fast blue, normal nerves showed an average of 2–3 mast cells/field. At 4 weeks, there were 9.25 for the simple nerve sutures and 16 for the augmented repairs. At 10 weeks, there were 23 and 27.6. When assessed by mast cell tryptase, there were no positives in the controls. At 4 weeks, we found an average of 4 in the simple sutures and 2.5 in the augmented repairs. At 10 weeks, there were 4.5 and 0.2. In controls, there were 1–2 CD34+ blood vessels per field. At 4 weeks, simple repairs showed an average of 4 and, in those with adipose addition, 5.5. At 10 weeks, there were 7 and 12. Mechanically processed adipose tissue augmented nerve repair does not seem to increase mast cell expression but may support angiogenesis in an experimental model.

A Topographic Atlas of the Human Brainstem in the Ponto-Mesencephalic Junction Plane

The human brainstem harbors neuronal aggregates that ensure the maintenance of several vital functions. It also acts as a major relay structure for the neuronal information that travels between the cerebral cortex, the cerebellum and the spinal cord. As such, this relatively small portion of the human brain houses a multitude of ascending and descending fibers that course among numerous nuclei whose exact boundaries are still uncertain. Such a large number of nuclei and fiber tracts confined to a relatively small and compact brain region imposes upon the brainstem a highly complex cytoarchitectonic organization that still needs to be deciphered. The present work provides a topographic atlas of the human brainstem composed of 45 anatomical plates, each containing a pair of adjacent sections stained with Cresyl Violet and Luxol Fast Blue to help delineating brainstem nuclei and fiber tracts, respectively. The plates, which cover the entire midbrain, pons and medulla oblongata, are composed of equally-spaced sections referenced and aligned parallel to the ponto-mesencephalic junction rather than the fastigium or the obex. This topographic landmark is particularly suitable for neurosurgical interventions aiming at specific nuclei of the mesencephalic tegmentum. In complement, we provide 8 anatomical plates containing adjacent sections stained for choline acetyltransferase and Luxol Fast Blue, taken through the midbrain and the pons. This open access atlas of the human brainstem is intended to assist neuroanatomists, neurosurgeons and neuropathologists in their work.

Neural and vascular architecture of the septum pellucidum: an anatomical study and considerations for safe endoscopic septum pellucidotomy

OBJECTIVEThe septum pellucidum is a bilateral thin membranous structure representing the border between the frontal horns of the lateral ventricles. Its most examined components are the septal veins due to their surgical importance during endoscopic septum pellucidotomy (ESP), which is a well-accepted method for surgical treatment of unilateral hydrocephalus. It is widely accepted that the septum pellucidum contains nerve fibers as well, but interestingly, no anatomical study has been addressed to its neural components before. The aim of the present study was to identify these elements as well as their relations to the septal veins and to define major landmarks within the ventricular system for neurosurgical use.METHODSNine formalin-fixed human cadaveric brains (18 septa pellucida) were involved in this study. A central block containing both septa pellucida was removed and frozen at −30°C for 2 weeks in 7 cases. The fibers of the septum pellucidum and the adjacent areas including the venous elements were dissected under magnification by using homemade wooden spatulas and microsurgical instruments. In 2 cases a histological technique was used to validate the findings of the dissections. The blocks were sliced, embedded in paraffin, cut in 7-µm-thick slices, and then stained as follows: 1) with H & E, 2) with Luxol fast blue combined with cresyl violet, and 3) with Luxol fast blue combined with Sirius red.RESULTSThe septum pellucidum and the subjacent septum verum form the medial wall of the frontal horn of the lateral ventricle. Both structures contain nerve fibers that were organized in 3 groups: 1) the precommissural fibers of the fornix; 2) the inferior fascicle; and 3) the superior fascicle of the septum pellucidum. The area directly rostral to the postcommissural column of the fornix consisted of macroscopically identifiable gray matter corresponding to the septal nuclei. The histological examinations validated the findings of the authors’ fiber dissections.CONCLUSIONSThe nerve elements of the septum pellucidum as well as the subjacent septum verum were identified with fiber dissection and verified with histology for the first time. The septal nuclei located just anterior to the fornix and the precommissural fibers of the fornix should be preserved during ESP. Considering the venous anatomy as well as the neural architecture of the septum pellucidum, the fenestration should ideally be placed above the superior edge of the fornix and preferably dorsal to the interventricular foramen.

Central Blindness Associated with a Pituitary Adenoma in a Mare

Background: Pituitary pars intermedia (PI) adenoma is a benign adenohypophysis neoplasm, rare in Brazil, which may compress adjacent structures and lead to dysfunctions of the endocrine organs. The most affected species are equines, particularly aged animals. This neoplastic disease is often associated with Cushing's syndrome, when the pituitary-adrenocortical axis is affected. However, this neoplasm is seldom associated with clinical blindness. This paper describes a case of pituitary pars intermedia (PI) adenoma which caused blindness in a mare.Case: An emaciated, blind mare that had difficulty finding water and food was referred to “Hospital Veterinário de Grandes Animais” of “Universidade Federal Rural do Rio de Janeiro”, in Seropédica, state of Rio de Janeiro, Brazil, and later to the “Setor de Anatomia Patológica” (SAP/UFRRJ) for necropsy. During necropsy it was found that the animal’s pituitary gland consisted of a circumscribed globous mass measuring 3.5x2.5x2.5 cm, symmetrical and well delimited at the sella turcica. Several organs were collected, fixed in 10% formalin and then processed for histological examination. The brain was subjected to serial cleavage along the path of the vision organs. All collected tissues were stained with hematoxylin and eosin; the pituitary was stained with Schiff Periodic Acid (PAS) to differentiate neoplastic cells and with Luxol Fast Blue to evidence demyelination. Histopathology found that the pars intermedia (PI) was thickened and compressed the neurohypophysis and adenohypophysis. Cells were arranged in a disorganized manner or formed follicles or cysts containing eosinophilic material (colloid), with granules strongly positive after staining with PAS. Proliferated cells were large, polyhedral to ovoid, and contained clear basophilic granular material. The nuclei were spherical to ovoid and there were light anisocytosis and anisocariasis. Cysts were frequently found in the pars intermedia (PI) and occasionally in the pars distalis. Mitoses were rare, less than one per field of greatest increase. In some areas of the pars intermedia (PI), cells were arranged in a solid manner forming spherical sub-nodules. An orange yellow pigment was observed in the pericary (lipofuscinosis) in various neurons of several areas of the central nervous system and of the trigeminal ganglion. In the optic tract, there were areas with moderate demyelination, evidenced by Luxol Fast Blue staining, and macrophages characterizing the so-called digestion chambers. In the right and left lateral geniculate nuclei a focal area of neurons with pyknotic and peripheral nuclei, marginal Nissl substance (central chromatolysis) and atypical and reactive astrocytes was observed, with increased volume, evident cytoplasm and nuclei with marginated chromatin which was sometimes reniform.Discussion: This paper presents the pathological findings obtained from a mare with central blindness due to pituitary pars intermedia adenoma. The analysis of the structures affected and correlation of alterations with the respective clinical signs are compared with alterations in other areas of the pituitary which generate clinical signals not observed in this mare, but which occur more often in equines with tumors in that organ. Thus, central and bilateral blindness was associated with compression of the optical tracts by the neoplastic mass and consequent death of neurons of the lateral geniculate nucleus. Pituitary PI adenoma should be considered as a differential diagnosis for blindness.

Pre, intra and post-ischemic hypothermic neuroprotection in temporary focal cerebral ischemia in rats: morphometric analysis

OBJECTIVE: To evaluate the neuroprotection of mild hypothermia, applied in different moments, in temporary focal cerebral ischemia in rats. METHODS: Rats was divided into Control (C), Sham (S), Ischemic-control(IC), Pre-ischemic Hypothermia (IH1), Intra-ischemic Hypothermia (IH2), and Post-ischemic Hypothermia (IH3) groups. Morphometry was performed using the KS400 software (Carl Zeiss®) in coronal sections stained by Luxol Fast Blue. Ischemic areas and volumes were obtained. RESULTS: Statistically, blue areas showed difference for C vs. IC, IC vs. IH1 and IC vs. IH2 (p=0.0001; p=0.01; p=0.03), and no difference between C vs. S, IC vs. IH3 and IH vs. IH2 (p=0.39; p=0.85; p=0.63). Red areas showed difference between C vs. IC, IC vs. IH1 and IC vs. IH2 (p=0.0001; p=0.009; p=0.03), and no difference between C vs. S, IC vs. IH3 and IH1 vs. IH2 (p=0.48; p=0.27; p=0.68). Average ischemic areas and ischemic volumes showed difference between IC vs. IH1 and IC vs. IH2 (p=0.0001 and p=0.0011), and no difference between IC vs. IH3 and IH1 vs. IH2 (p=0.57; p=0.79). CONCLUSION: Pre-ischemic and intra-ischemic hypothermia were shown to be similarly neuroprotective, but this was not true for post-ischemic hypothermia.

Utilização de células-tronco autólogas de medula óssea na regeneração do nervo tibial de coelhos mediante técnica de tubulização com prótese de silicone

Neste estudo é apresentado um modelo experimental de defeito agudo em nervo periférico para avaliação da regeneração nervosa mediante técnica de tubulização associada à inoculação de células-tronco autólogas de medula óssea. Foram utilizados 12 coelhos Nova Zelândia albinos, submetidos à secção bilateral e ao afastamento de 5mm do nervo tibial e posterior reparo mediante utilização de câmara de silicone. Internamente à prótese de tubulização do nervo tibial esquerdo em todos os animais, foram inoculadas células-tronco autólogas de medula óssea, coletadas a partir do úmero. Como grupo controle (nervo tibial direito), mediante aplicação da mesma técnica de reparo, solução de NaCl 0,9% foi administrada internamente à prótese. Após 30 dias de observação, os animais foram eutanasiados e foi realizada a avaliação histológica dos segmentos nervosos por meio das colorações de hematoxilina-eosina, luxol fast blue e azul de toluidina. Com os resultados, foi possível concluir que o transplante de células-tronco autólogas associado à técnica de tubulização apresenta vantagens no processo de regeneração nervosa periférica.