M. Zurita

Effect of fibrin glue on postlaminectomy scar formation

SummaryAn experimental study in rats has been carried out with the aim of studying the scar formation over the spinal dura in the presence of fibrin glue. Although the main action of fibrin glue is the enhancement of wound healing by increasing the fibrous tissue, our present data suggest that this re-absorbable biomaterial diminishes the epidural scar formation, at least the first two weeks after laminectomy. This finding leads us to consider the use of fibrin glue over spinal duramater when it is likely that reoperation may become necessary in a short period of time after a laminectomy.

Experimental induction of primitive neuro-ectodermal tumours in rats : a re-appraisement of the ENU-model of neurocarcinogenesis

SummaryA series of 122 experimental brain tumours, induced in the Wistar rat by means of prenatal exposition to ethyl-nitrosourea, were studied with histological, immunohistochemical and ultrastructural techniques. Although with conventional histological techniques, most of the induced tumours showed morphological features suggesting their classification as malignant schwannomas or oligodendroglioma-like neoplasms, their study by means of immunohistochemistry and electron microscopy suggested that they are, in fact, primitive neuroectodermal tumours, with a tendency toward neuronal differentiation. This finding obliges us to re-appraise the ethyl-nitrosourea model of neurocarcinogenesis and to consider its possible usefulness for the experimental study of therapeutic approaches with potential applications in human neuro-ectodermal neoplasms.

Expression and significance of vascular permeability factor in tumour infiltrating lymphocytes of brain metastases.

Summary Background. Recently, vasogenic edema has been related to the expression of vascular permeability factor (VPF) by tumour cells in brain metastases. On the other hand, expression of VPF has been reported in inflammatory cells. Keeping in mind the current presence of tumour-infiltrating lymphocytes (TIL) in brain metastases, our objective is to study the expression and significance of VPF in TIL-cells from specimens of brain metastases. Method. Tumour samples from 16 brain metastases associated with peritumoural edema were immunohistochemically studied for demonstration of VPF. The degree of VPF-expression by tumour cells and TIL was determined, and correlated with the degree of peritumoural edema. Findings. Our present results show that, independently of the VPF-positivity expressed by the tumour cells, VPF-expression is a constant finding in TIL-cells of brain metastases, and correlated with the amount of peritumoural edema. Interpretation. Our present findings suggest a role for TIL-cells in the development of vasogenic edema associated with brain metastases.

Imbalance between apostain expression and proliferative index can predict survival in primary glioblastoma.

Summary.Summary. Background: Cell proliferation and cell death are opposing processes in tumour growth, with tumour progression reflecting the balance between proliferating and apoptotic cells. The purpose of the present study is to verify the hypothesis that an imbalance between apoptosis and proliferation can predict survival in patients with primary glioblastoma. Methods: After the immunohistochemical study of Apostain and MIB-1 expression, the index of apoptosis (AI), the index of proliferation (PI), and the ratio AI/PI was recorded for each tumour specimen, in a series of 32 primary glioblastomas. Studies of correlation between AI and PI, between AI and survival, between PI and survival, and between the ratio AI/PI and survival, were performed using the Spearman rank correlation test. Furthermore, a comparative study of survival was performed for subgroups of patients with ratio AI/PI greater or lesser than 1, using the log rank test. Findings: In the present series, values of AI and PI showed a wide distribution, with a mean±SD of 8.16±7.2, and of 12.69±21.1, respectively. The values for the ratio AI/PI ranged between 0.01 and 6.03 (mean±SD: 1.44±1.60). Statistical study failed to obtain correlation between AI and PI. Survival of patients not correlated with AI neither with PI. The ratio between AI and PI did not correlate with survival either. Nevertheless, when survival for the subgroups of patients showing a ratio AI/PI greater or lesser than 1 was compared, a significant difference was found (p: 0.02). Survival ranged between 50 and 81 weeks (mean of 58.5±11.05 weeks) for the 12 cases showing a ratio AI/PI greater than 1, and it ranged between 8 and 85 weeks (mean: 38.20±25.37 weeks) for the 20 cases showing a ratio AI/PI lesser than 1. Interpretation: Our present results suggest that a clear imbalance between cell proliferation and apoptosis can predict outcome in patients operated on for a primary glioblastoma.

Delayed transplantation of foetal cerebral tissue into injured spinal cord of adult rats

SummaryDelayed transplantation of foetal cerebral tissue into injured spinal cord of adult rats was performed for the purpose of evaluating the usefulness of the procedure for reconstructing the spinal cord and providing motor recovery. Transplanted tissue showed a survival rate greater than 80% and integration with the host tissue. Nerve fibers of the host surrounded the transplanted tissue, penetrating it. Foetal cerebral neurons matured into recipient spinal cord, but they were not organized in layers. The experience obtained suggests that delayed transplantation of foetal cerebral tissue into contused spinal cord is useful in morphological spinal cord reconstruction. Nevertheless, at least during the first two months after transplantation, clinical assessment of motor recovery showed no differences between transplanted and nontransplanted rats.

Gangliosides modulate the growth rate and cell phenotype of a murine primitive neuro-ectodermal tumour

SummaryIntratumoural administration of gangliosides (GSD) into a murine primitive neuro-ectodermal tumour, growing in the epicranial subcutaneous tissue of syngenic rats, results in a decrease in the tumour growth rate and causes a more differentiated phenotype of tumour cell, with immunohistochemical expression of neuronal markers. These findings suggest that the potential usefulness of intralesional administration of GSD for the control of tumours of primitive neuro-epithelial character could be considered.

Apoptosis is not correlated with the presence of CD57+ NK-cells in brain metastases

Summary¶Background. Cell apoptosis in solid tumours has been related to immunological attack by NK-cells. The purpose of the present study is to verify in the tissue of brain metastases a possible relationship among the degree of NK-cell infiltration and the number of apoptotic tumour cells.Methods. Twenty brain metastases whose tumour cells expressed CD95 (Fas/APO1) have been studied. NK-cells were identified by using the monoclonal antibody to CD57, and apoptotic tumour cells by means of the immunostain with the anti-ssDNA monoclonal antibody F7-26. The Spearman rank correlation test was used to study the relationship between the degree of CD57-NK-cell infiltration and the apoptosis labelling-index.Findings. Positivity to F7-26 was present in all tumour samples, but the number of immunostained cells showed a wide variability, with a mean apoptosis labelling-index of 11.48%. All the studied tumours showed CD57 immunostained cells, with a number that ranged between 4 and 20 per microscopical field at 200× (mean±standard deviation: 8.4±3.7). Statistical studies showed that there was no correlation between the number of CD57 immunostained NK-cells and the apoptosis labelling-index (p>0.05).Interpretation. These findings suggest that in brain metastases, apoptosis related to immune r esponse is mainly mediated by activated tumour-infiltrating mononuclear cells other than CD57+ NK-cells.

Possible role for vascular permeability factor in the pathophysiology of vasogenic oedema associated to brain abscess.

Vasogenic perilesional edema is a characteristic of cerebral abscesses. However, the mechanisms by which this edema is developed, are not very wellknown. Keeping in mind that vascular permeability in diverse pathological conditions is induced by vascular endothelial permeability factor (VPF) [1±5] we have studied the presence of this cytokine in the tissue of brain abscesses and in the adjacent white matter, with the purpose of ®nding data supporting the hypothesis that vasogenic edema is related to presence of VPF in brain abscesses.

Postlaminectomy scar formation in presence of epidural vicryl-collagen prostheses☆

Summary An experimental study was performed in rats to evaluate the potential usefulness of the vicryl-collagen prosthesis in limiting epidural scar formation after laminectomy. The results obtained suggest that the presence of the prosthesis in the epidural space did not significantly influence the density or thickness of epidural scar tissue. Nevertheless, the fact that this material was well tolerated, being replaced by fibrous tissue without inflammatory tissular response, suggests that its use in the epidural space may be preferable to that of other absorbable materials and supports earlier studies suggesting the usefulness of the vicryl mesh as a dural substitute.

Tumor neuroepitelial disembrioplásico: una causa de epilepsia curable quirúrgicamente

Resumen Los llamados «Tumores neuroepiteliales disembrioplasicos » (TND) fueron individualizados en 1988 por Daumas-Duport y cols. Clinicamente se manifiestan por una historia de larga evolucion consistente en crisis epilepticas rebeldes al tratamiento medico. Anatomopatologicamente sus celulas predominantes son de pequeno tamano, con aspecto similar, desde el punto de vista de la microscopia optica, al de las celulas de oligodendroglia, y se asocian a alteraciones neuronales, con desorganizacion de la corteza cerebral. En la presente publicacion se aportan 2 nuevos casos de TND y se revisan los aspectos anatomoclinicos de esta entidad. Nuestros hallazgos confirman observaciones previas en el sentido de que estas neoplasias son biologicamente benignas y constituyen basicamente lesiones epileptogenicas susceptibles de ser tratadas quirurgicamente con magnificos resultados. Por otra parte, el estudio anatomopatologico realizado en nuestros casos demuestra la naturaleza neuronal de estos tumores, lo que unido a observaciones recogidas en la literatura, nos lleva a sugerir que los llamados «tumores neuroepiteliales disembrioplasicos» deberian ser reclasificados como «neurocitomas disembrioplasicos».