How to repair an ischemic brain injury? Value of experimental models in search of answers.

The major aim of experimental models of cerebral ischemia is to study the cerebral ischemic damage under controlled and reproducible conditions. Experimental studies have been fundamental in the establishment of new concepts regarding the mechanisms underlying the ischemic brain injury, such as the ischemic penumbra, the reperfusion injury, the cell death or the importance of the damage induced on mitochondria, glial cells and white matter. Disagreement between experimental and clinical studies regarding the benefit of drugs to reduce or restore the cerebral ischemic damage has created a growing controversy about the clinical value of the experimental models of cerebral ischemia. One of the major explanations for the failure of the clinical trials is the reductionist approach of most therapies, which are focused on the known effect of a single molecule within a specific pathway of ischemic damage. This philosophy contrasts to the complex morphological design of the cerebral tissue and the complex cellular and molecular physiopathology underlying the ischemic brain injury. We believe that the main objective of studies carried out in experimental models of cerebral ischemic injury must be a better understanding of the fundamental mechanisms underlying progression of the ischemic injury. Clinical trials should not be considered if the benefit obtained in experimental studies is limited or weak.

Intraventricular craniopharyngiomas: topographical classification and surgical approach selection based on an extensive overview.

BACKGROUND: This retrospective study analyzes the clinical, neuroradiological, pathological and surgical characteristics of well-described intraventricular craniopharyngiomas with the aims of: (i) critically to review the criteria used to affirm the diagnosis of an intraventricular location (ii) defining more accurately this topographical diagnosis preoperatively, and (iii) to investigate factors influencing the surgical outcome. METHOD: Clinical, neuroradiological, pathological and surgical objective data of 104 well-described intraventricular craniopharyngiomas (IVC) reported in the literature, in addition to a new case, were analyzed. On the basis of the proofs provided for third ventricle intactness, a new topographical classification for IVC was developed, distinguishing between: (i) strict IVC, with a proved third ventricle floor integrity and (ii) non-strict IVC, without any reliable proof confirming the intactness of the third ventricle floor. Following this classification, clinical features, pathology and surgical outcome for strictly and non-strictly IVC were compared. FINDINGS: For 105 IVC compiled, 36 belonged to the strictly group and 69 to the non-strictly group. Two pathological features were associated with the non-strictly IVC group: a preferentially adamantinomatous pattern (p=0.106) and wider and tighter adherences to third ventricle margins (p=0.01). The non-strict topography was also associated with a worse postoperative outcome (p=0.046). There was a significant relationship between the surgical approach and the final outcome (p=0.05), being the translamina terminalis approach associated with the best outcome. CONCLUSIONS: Two different topographies might be considered among IVC: strict and non-strict intraventricular location. Non-strictly IVC have wider and tighter adhesions to third ventricle boundaries and this subtype is associated with a worse outcome.

[Blood brain barrier: development of a structure which supports the functional heterogeneity of the central nervous system]. / La barrera hematoencefalica: desarrollo de una estructura que permite la heterogeneidad funcional del sistema nervioso central.

AIMS: To analyze the functional reasons justifying the existence of the blood brain barrier with an emphasis on its fundamental role supporting neuroglial coupling. DEVELOPMENT: We review in an integrated manner the contributions of different research areas in physiology and metabolism of the central nervous system which allow to understand the functional need for the existence of the blood brain barrier. In particular, we describe the physiological basis of the metabolic functional coupling and the metabolic interactions between neurons and glial cells, two properties directly derived from the presence of the blood brain barrier. Likewise the blood brain barrier is presented as an important determinant of the heterogeneous activation of cerebral tissue as detected by neuroimaging technologies as positron emission tomography and functional magnetic resonance imaging. CONCLUSIONS: The main function of the blood brain barrier is to maintain a stable composition of the extracellular milieu in nervous tissue. This allows the changes in ionic composition and neurotransmitter concentration in the extracellular milieu, to reflect indirectly the generation of action potentials and the state of neurotransmission of neuronal circuits. Glial cells induce the development of the blood brain barrier and are the main sensors of neuronal function, due to their important take up capacity for extracellular potassium and neurotransmitters. Glial homeostasis of the extracellular milieu is circuit specific, limiting the functional metabolic coupling to discrete regions of the brain and generating the classical pattern of heterogeneous activity in the different modules of the nervous tissue.

[The role of the extra-intracranial anastomosis and interventionist endovascular therapy in the treatment of complex cerebral aneurysms]. / Papel de la anastomosis extra-intracraneal y de la terapia endovascular intervencionista en el tratamiento de aneurismas complejos cerebrales.

Cerebral revascularization is an useful tool in the treatment of giant or complex cerebral aneurysms that can not be clipped directly by different causes. In turn, interventionist endovascular therapy, an emergent technique with very good results in the treatment of cerebral aneurysms during the last five years, is a new complementary tool to cerebral revascularization for the treatment of complex aneurysms. In the present manuscript we emphasize the beneficial effect of revascularization, followed in a short period of time by the endovascular technique in order to either occlude the parent vessel or to exclude the aneurysm from cerebral circulation. Advantages of this form of therapy, as well as the selection of patients and the present revascularization procedures, are commented.

[Anatomic and hemodynamic study of anterior communicating artery complex]. / Bases anatómicas y hemodinámicas del complejo de la arteria comunicante anterior.

Anterior communicating artery complex accounts for the most frequent site of cerebral aneurysms and it is characterized by its great anatomical variability. The development of aneurysms in this complex has been associated with the asymmetry of its afferent vessels. An anatomical and hemodynamic study of the anterior communicating artery was performed. Twenty brain samples obtained from adult necropsies were studied by means of microsurgical dissection. Additionally; 118 cerebral angiographies from patients with spontaneous subarachnoid hemorrhage were studied. A high number of perforanting vessels originated at the anterior communicating artery complex was a relevant finding. The number, distribution and size of these vessels is reported accurately. Analysis of the angiographies showed the association between the existence of an anterior communicating artery aneurysm and the presence of a blood flow predominance through one of the two proximal anterior cerebral arterias.

Primary hypothalamic-third ventricle lymphoma. Case report and review of the literature.

Primary central nervous system lymphomas (PCNSL) are infrequent tumors and their presentation as a solitary hypothalamic-third ventricle mass can be considered exceptional. We report the case of a 57-year-old woman with progressive visual deterioration, diabetes insipidus and mental confusion. She had a diffuse and homogeneous tumoral lesion involving the third ventricle and the adjacent hypothalamic area with marked enhancement after contrast administration on both, competed tomography scan and magnetic resonance images. It was approached and partially resected by the translamina terminalis route. Histological diagnosis proved to be a diffuse non-Hodgkin lymphoma and the patient subsequently was treated with adjuvant radiotherapy and chemotherapy. Followup examination showed visual acuity recover but persistent confessional state. Eight similar well described cases reported in the literature are reviewed with a description of the major diffenciating features of this neurological entity. Treatment of PCNSL remains a challenge, and the topographical location within the hypothalamic-third ventricle area is even more complex.

Periosteal glomus tumor of the femur: a case report.

Osseous abnormalities produced by glomus tumors located in soft tissues of the periungual region have been described. More rare is the location of a glomus tumor within bone, which usually is located in the phalanx of the fingers. However, to the authors' knowledge, there is no previous description of a glomus tumor located in a periosteal location of a long bone. A 50-year-old man with a glomus tumor in a periosteal location of the lower metaphysis of the femur without neoplastic erosion of the cortical surface is reported. Magnetic resonance imaging and intraoperative ultrasonography were needed to locate the lesion.

Nonhistological diagnosis of human cerebral tumors by 1H magnetic resonance spectroscopy and amino acid analysis.

We describe a multivariate analysis procedure to classify human cerebral tumors nonhistologically in vitro, combining the use of 1H magnetic resonance spectroscopy (MRS) with automatic amino acid analysis of biopsy extracts. Eighty-one biopsies were obtained surgically and classified histologically in eight classes: high-grade astrocytomas (class 1, n = 19), low-grade astrocytomas (class 2, n = 10), normal brain (class 3, n = 9), medulloblastomas (class 4, n = 4), meningiomas (class 5, n = 18), metastases (class 6, n = 8), neurinomas (class 7, n = 9), and oligodendrogliomas (class 8, n = 4). Perchloric acid extracts were prepared from every biopsy and analyzed by high resolution 1H MRS and automatic amino acid analysis by ionic exchange chromatography. Intensities of 27 resonances and ratios of resonances were measured in the 1H MRS spectra, and 17 amino acid concentrations were determined in the chromatograms. Linear discriminant analysis provided the most adequate combination of these variables for binary classifications of a biopsy between any two possible classes and in multiple choice comparisons, involving the eight possible classes considered. Correct diagnosis was obtained when the class selected by the computer matched the histological diagnosis. In binary comparisons, consideration of the amino acid profile increased the percentage of correct classifications, being always higher than 75% and reaching 100% in many cases. In multilateral comparisons, scores were: high-grade astrocytomas, 80%; low-grade astrocytomas, 74%; normal brain, 100%; medulloblastomas, 100%; meningiomas, 94.5%; metastases, 86%; neurinomas, 100%; and oligodendrogliomas, 75%. These results indicate that statistical multivariate procedures, combining 1H MRS and amino acid analysis of tissue extracts, provide a valuable classifier for the nonhistological diagnosis of biopsies from brain tumors in vitro.