The vascular stem cell niches and their significance in the brain.

AIM: This cytohistopathological study was performed for a better knowledge of phenotypes derived from pluripotent stem cells, as well as for precise location of stem cells within the vascular niche in the brain. METHODS: We used light and transmission electron microscopy to demonstrate the presence of stem cells in the vascular wall of microvessels in the cerebral and cerebellar cortex, pia mater (considered by us a cordocytic-vascular tissue), adventitia of larger cortical arteries and veins, and around vessels. We investigated multiple vascular segments and brain tissue in a variety of clinical cases, such as cerebral tumors, cerebrovascular malformations, thromboses in the carotid system, and direct laceration. RESULTS: Our morphological and ultrastructural observations pointed out many changing phenotypes, as well as cell interrelationships within the vascular niche, both for repair processes when cordocytes cooperate with mesenchymal stem cells, and pathological processes such as atherogenesis, tumorigenesis, and neurotrauma. Our results underlie the important roles of cordocytes in their interrelations with precursor/stem cells in the arterial adventitia. CONCLUSION: The cells derived from pluripotent stem cells along different lineages have had different phenotypes as they derived from hematopoietic stem cells or mesenchymal stem cells, with or without epigenetic disregulations or depending on different microenvironments. Cell interactions, phenotypes, and underlying mechanisms, as well as biological responses to different small molecules or compounds, remain to be determined by future molecular insights within the vascular niche.

Primary tumors of the lateral ventricles of the brain.

BACKGROUND: The lateral ventricles are located in the center of the brain. Each ventricle lies in contact with five critical neural structures: the caudate nucleus, the thalamus, the fornix, the corpus callosum, and the genu of internal capsule.The authors report their experience in primary tumors of the lateral ventricles of the brain by analysing the symptomatology,the surgical treatment, the complications and the postoperative results. OBJECTIVE: To determine the importance of the surgical technique on the morbidity and the recurrence of lateral ventricles tumors. Total surgical resection followed by radiotherapy and or chemotherapy had been the main objective in the cases of anaplastic tumors. METHODS: This retrospective study makes reference to 202 primary tumors of the lateral ventricles operated by Leon Danaila between 1982 and 2012. The respective analysis is based on the operative approaches and on the extent of resection. The surgical access routes were the interhemispheric transcallosal approach and the transcortical approach. RESULTS: A number of 177 (87%) of the primary tumors of the lateral ventricles were benign (low grade lesions), while 25(12.37%) of them were anaplastic. The most frequent tumors were ependymomas, astrocytomas, subependymomas, choroid plexus papillomas and meningiomas. Out of the total of 202 tumor cases, 164 (81.18%) were discharged with very good and good results, 35 (17.32%) were left with neurological deficits,and 3 (1.48%) died. A significant proportion of the patients undergoing surgery develop cerebrospinal fluid outflow obstruction, and this fact made the postoperative mounting of a number of ventricular shunts necessary. CONCLUSION: The majority of these tumors were benign, with are latively slow growth rate. Owing to this fact, the preoperative dimensions of the tumors were of several centimeters. The average age of the patients was lower than that of those with similar lesions located intraparenchymatously. The symptoms were determined by the ventricular outflow obstruction and by the affectation of the periventricular structures. Interhemispheric transcallosal and transcortical approaches were the best surgical access routes.

Surgery of tumors of the third ventricle region.

BACKGROUND: The third ventricle is located in the center of the brain, surrounded by critical structures. The authors reported their experience in the surgical treatment of tumors originated from or expanding within the third ventricle, analysing the postoperative results and patient's outcome. MATERIAL AND METHODS: We performed a retrospective study on 120 patients, who had been operated in our neurosurgical department for tumors of the third ventricle and adjacent region over the last 21 years. According to their place of origin, these tumors were divided into primary tumors of the third ventricle (69 cases) and tumors developed from the surrounding structures (51 cases). The patients were operated on via a transcallosal-transventricular approach (58.34%), transcortical parieto-occipital approach (26.67%) or subfrontal approach (15%). Microsurgery has been used in all cases. In 20 patients (16.67%), preoperative ventricular drainage was performed. Stereotactic procedures were not used in this study. RESULTS: The overall mortality in this series was 11.67% (14 120 died). The death was directly correlated to the surgery in 8 cases, to general complications in 3 cases, to recurrence of the tumor in 2 cases, and to shunt malfunction in one case. Perioperative good evolution (GOS 5) was noted in 54 patients (45%), but at one-year follow-up, good neurological evolution was recorded in 72 patients (60%). The long-term neurological outcome recorded neurological impairments in 21.42% of patients, a permanent diabetes insipidus in 5.1% of patients and the persistence of neuropsychological deficits in 28.57%. The recurrence of the tumor has been encountered in 16 patients (13.34%). CONCLUSIONS: Transcallosal approach remains the best method for the microneurosurgical treatment of third ventricle tumors. This route provides the capability for a superior visualization of the entire cavity of the third ventricle through different corridors, and permanent neurological and neuropsychological deficits are not frequent.

Kármán-Howarth closure equation on the basis of a universal eddy viscosity.

This Rapid Communication presents a simple closure for the two-point correlation transport equation in decaying isotropic turbulence. It relies essentially on an eddy viscosity ν(t) which exhibits some remarkable universal facets over an impressively wide range of scales. This allows us to model the third-order structure functions in different decaying flows covering a large extent of Reynolds numbers. The model is numerically time integrated to predict the decay of second-order structure functions and compared to experiments in grid turbulence. Agreement between predictions and measurements is satisfactory.

Apoptosis, paraptosis, necrosis, and cell regeneration in posttraumatic cerebral arteries.

This study is to understand the nature and functional significance of the activated cell death programs and rehabilitation signs during late vascular changes after brain injury. We used light and transmission electron microscopy to describe changes of cells within the vascular endothelium and tunica media of the cortical arteries four weeks after craniocerebral traumatism. Within tunica media of the posttraumatic damaged artery, apoptotic and paraptotic phenotypes were identified as well as some early ultrastructural signs of smooth muscle cells regeneration, these cell highlighting a remarkable degree of plasticity. Surprisingly, some endothelial cells showed an extensive rough endoplasmic reticulum development, whereas other endothelial cells showed typical necrosis. In conclusion, two groups of suicidal cells apoptotic and paraptotic cells were encountered in the same lesional vascular wall after neurotrauma, showing also signs of cell regeneration. The pathophysiologic significance of the coexisting double cell death programs and cell regeneration seems to be in relation with late cell survival, after arterial damage when some cells disappear and other cells try to survive undergoing reversible injury.

Endovascular minimally invasive treatment of the intracranial aneurysms--first 124 cases.

INTRODUCTION: Since May 2005, we have started to treat the intracranial aneurysms endovascular way as an alternative minimally invasive technique to the classic neurosurgery treatment. OBJECTIVE: Studying the patients' demographics, clinical presentation, aneurysm size and configuration, type of coils used for embolization, the percentage of compaction and recanalization (especially in patients who presented with subarachnoid hemorrhage), and immediate complications. METHODS AND RESULTS: An all-inclusive retrospective review of every patient who underwent coils embolization (stent or balloon assisted included) of saccular aneurysms from May 2005 to September 2011 was performed. A total of 116 patients (46 men and 60 women) and 124 aneurysms were treated. A total of 96 patients (41 men and 55 women) underwent follow-up femoral cerebral angiograms (mean follow-up was 25 months and the longest was at 37 months). Five patients required intra-arterial abciximab due to thrombus formation. Four patients had aneurysm rupture while the coil was being advanced. Eleven patients were treated during vasospasm peak. Seven patients had recanalization at 12 months follow-up. DISCUSSION: The average hospitalization period was of 4 days. There is a close relation between Hunt and Hess scale score before treatment and post interventional neurological status. Due to subarachnoid hemorrhage, the vasospasm remains a threat to the patient's neurological status. The treatment of cerebral aneurysms with endosacular embolization by coils is a safe and durable option. The risk of recanalization or re-rupture in our cohort is small compared to series published elsewhere. Larger series of patients are needed to support our evidence.

[Surgical treatment of single brain metastases]. / Tratamentul chirurgical al metastazelor cerebrale unice.

Recent neurosurgical statistics indicate brain metastases as the most frequent intracerebral tumor. Under these circumstances, single brain metastases study and therapeutic management represent a major problem for a neurosurgeon and his efforts to prolong the patient survival rate and improve their quality of life. This study of the surgical treatment of single brain metastases has focused on a survey of the data which highlight most accurately the efficiency of a therapeutic method: general survival data or survival data function of primary neoplasm, mortality rate and causes, data regarding the connection between survival rate and death cause, tumor relapse rate, post surgery complications and post surgery neurological status. This study has surveyed a group of 320 patients presenting single brain metastases, which have been subject to surgery between 2001-2010. Median general survival rate for the patients with single brain metastases in this group was 9.64 months, regardless of the histologic type of the primary neoplasm. These data complies with other studies in the most majority of neurosurgical series which indicate a median survival of 10 months. The study clearly showed that the longest median survival rate was noticed in case of patients with a neurological death cause (12.54 months) and the shortest in case of patients deceased due to the systemic disease dissemination (5.08 months). A good neurological state prior to surgery, administering a complete surgical treatment, followed by radiotherapy and/or chemotherapy, as well as a good therapeutic control of the primary neoplasm are the decisive factors in obtaining the longest survival rate and the lowest risk in triggering systemic dissemination.

Microsurgical treatment of the interhemispheric arteriovenous malformations.

From a total of 364 patients who underwent surgery for AVMs, 46 (12.63%) had lesions located interhemispherically. The majority of patients have entered the 4th and 5th age decade. The youngest operated patient was 18 years old and the oldest was 64. The most frequent clinical signs encountered were headaches (13 - 28.2%), epilepsy (21 - 45.65%), motor deficits (12 - 26.08%), sensitivity disorders (8 - 17.39%), speech disabilities (4 - 8.69%), visual field deficits (3 - 6.52%), mental disorders (5 - 10.85%) and alteration of consciousness (4 - 8.69%).The initial imagistic examination consisted of a noncontrast computed tomographic scan, followed by a magnetic resonance angiography (MRA) and a digital subtraction angiography. We included the 46 patients into the Spatzler-Martin scale based on the location, the proximity to the eloquent areas, as well as on the type of the venous drainage. Next we show the number of patients included in every grade of the scale. Grade I - 7 (15.21%) patients, Grade II - 17 (36.95%) patients, Grade III - 19 (41.30%) patients and Grade IV - 3 (6.52%) patients. An interhemispheric surgical approach was used for these AVMs. Excellent and good postoperative results has been obtained in 37 (80.43%) patients, fair results in 5 (10.86%), poor in 2 (4.34%) and 2 (4.34%) patients have died. One of the 2 deaths was caused by a haematoma in the bed of the AVM and the other was caused by a pulmonary embolism.

[Posterior fossa epidural hematoma]. / Hematomul epidural de fosa posterioara.

Posterior fossa epidural hematomas (PFEH) are rare entities, with dark prognosis due to their specific localization. Because the simptomatology is usually nonspecific or poor, the CT should be performed as soon as posible. MRI does not offer suplimentary benefits/informations in the great majority of PFEH. Depending on the bleeding source, the rate of clinical signs appearance and the gravity of evolution varies. Early diagnosis and surgical treatment should be performed in hematomas associated with mass effect or suplimentary injuries. In all cases, in PFEH patients a careful monitoring is necessary due to unpredictable evolution and rapid clinical worsening, requiring surgical intervention.

The thread-protective cell, a new cell performing multiple tasks.

Our research work, which has led us to discovering the new cerebral cell, has started 30 years ago. An important moment was the year 1986, when we have highlighted it for the first time, during a study upon the clarification of some undiscovered aspects of cerebral atherosclerosis. In 2006 we have initiated the publishing of our results at three congresses (Cape Town - 2006; San Diego - 2009 and Los Angeles - 2011) as well as in three Atlases, form 2006, 2008 and 2010. By means of the electronic microscope we have analyzed to this purpose alone, a number of neurosurgery patients, with 1176 cerebral, vascular, tumoral, cortical, choroid plexus tumor and infectious biopsies. The cell in question was named cordocit-protectocit (thread-protective cell) in order to highlight its morphological aspect of a belt band and its functional one, of protective element of the noble substance of the brain, acting for its defense against various aggressions, especially hemorrhagic. On this occasion we have discovered that the pia mater is made up of such protective cells, which also play a role in preventing the neuroblasts from migrating. When the chemotactants of our cells are not numerous enough, subcortical cell heterotopias will occur, at the level of the corona radiata, double cortex and other neuronal migration disorders which may generate epilepsy. Therefore, the pia mater should be considered from a cytodynamic perspective. The telocyte at the internal organs level (intestine, heart etc.) is nothing else but the interstitial cell of Cajal (ICC), described by Cajal more than 100 years ago. The ICC spontaneously initiate rhythmic electrical activity, much like the peacemaker cells of the heart.

[Primary intracerebellar hematomas: surgical indications, prognosis]. / Hematoamele intracerebeloase primare: indicatii chirurgicale, prognostic.

Intracerebellar primary hematoma are produced by spontaneous hemorrhages in the cerebellar parenchima and usually present an sudden onset. In the present study we analyzed a serie of 34 cases of primary intracerebellar hematoma, in patients of both genders, between 35 and 80 years old. Taking in account the incidence of symptoms, the clinical picture was dominated by the gait disturbances, headache and consciousness disorders. From the analyzed cases, 50% had had surgical indication and 50% benefits on conservative treatment. Even though the evolution was favorable in the great majority of cases,the mortality in the surgical treated group was lesser (5,88%) comparative to the conservative treated group (17,64%). The main criteria for surgical treatment were represented by GCS (Glasgow Coma Scale) score < or =13 or blood collections exceeding 3 cm in diameter.

Giant intracranial endolymphatic sac tumor (ELST). Case presentation and histogenetic considerations.

We present a giant tumor of the skull base compressing the brain in a 40-years-old man. The tumor was policystic at imaging. Its histopathology, immunohistochemical profile and long evolution suggest an endolymphatic sac tumor (ELST), a rare case of neoplasia. Since the patient had multiple otolaryngological procedures in his medical history, a possible traumatic pathogenesis could be suspected. On the other way, some immunohistochemical aspects found in our case may imply a histogenesis divergent from that currently accepted. This could be from either the organ of Corti or some local cells that generate a resemblance with a systemic tumor, the so-called benign mesothelioma. Further studies are needed in order to clarify this topic.

Angiocentric glioma: presentation of two cases with dissimilar histology.

OBJECTIVE AND IMPORTANCE: Angiocentric glioma (AG) is a recently described tumor of the brain which was included as a distinct entity in the 2007 WHO classification. To date only 26 cases have been reported in the literature. We describe two additional cases of this possibly confusing lesion of the brain. Emphasis is put on variations in the histopathological picture. CLINICAL PRESENTATION: The patients (20- and 55-year-old males) presented with seizures and headaches, respectively. Imaging examination showed a small cortical-subcortical tumor in each case. Both tumors were totally removed. MATERIAL AND METHODS: Paraffin blocks from the two cases were examined with classical histopathology stainings and immunohistochemistry for GFAP, vimentin, EMA, neurofilament protein, synaptophysin, S100 protein, CD31, CD34, FVIII, smooth muscle actin and Ki67. RESULTS: The tumor proliferation was restricted around small intraparenchymal vessels. Immunohistochemistry demonstrated positivity for glial and negativity for vascular or neuronal markers. The cell shape and arrangement was different in the two cases. CONCLUSIONS: AG is a peculiar tumor of uncertain histogenesis but with certain glial reactivity. Histopathology is variable but restricted, for unknown reasons, to perivascular areas. Apparently, a better prognosis than for other gliomas is distinctive. Further studies are needed in order to expand the information regarding the clinical behavior and therapeutic approach of this tumor type.

An intrajugular paraganglioma. Unusual presentation of a classical tumor.

Paragangliomas arise from the extraadrenal neuroendocrine system. They are locally aggressive tumors, causing adjacent invasion, bone destruction and compression related symptoms. We present a 35-years-old woman with a peculiar paraganglioma lacking all these features, and strictly located within the jugular vein. Differential diagnosis is detailed since other entities could have dissimilar clinical behavior. To the best of our knowledge, this is a very unusual site of occurrence for paragangliomas, and only two other comparable cases have been described.

Skull base tumor invading both cavernous sinuses. Adenoid cystic carcinoma mimicking a meningioma.

We present a case of an anterior skull base tumor invading both cavernous sinuses and extending into the right orbit in a 55 years old female. The radiological aspect was confusing, being highly suggestive for an extensively invasive meningioma. However, the orbital portion of the tumor, which was surgically removed, proved to be an adenoid cystic carcinoma. Some peculiar immunohistochemical findings were obvious, as well as a lack of continuity of the tumor with the local lacrimal gland. This is an unusual situation, when a lacrimal gland tumor spread along the cavernous sinus, cross the midline and approaches the contralateral orbit. Such local extension should be considered in the differential diagnosis of anterior skull base tumors.

p53 protein and bcl-2 expression in glioblastomas. Pathological correlations in a comprehensive series.

p53 and bcl-2 are two well-known antiapoptotic factors associated with gliomas, and mostly astrocytic tumors. In the present study we assessed, by immunohistochemistry, the expression of these two factors in a series of 50 glioblastomas. The correlations between their expression and several tumor-related factors (age, location, recurrence, proliferating potential) were investigated. Our results suggest that a valuable correlation between these factors cannot be found. This is in discrepancy with some literature data, which emphasize strong relations of p53 and bcl-2 in oncogenesis spreading or final prognosis. Further studies are needed, with unique, standard procedures for these evaluations.

Paraganglioma of the cerebellopontine angle. Case presentation and pathological considerations.

Paragangliomas (glomus tumors) arise from the extra-adrenal neuroendocrine system. They are benign but locally aggressive tumors, causing bone destruction and compression related symptoms. We present a case of paraganglioma of the cerebellopontine angle. Emphasis on possible difficulties in clinical, imaging or pathological identification, and surgical removal is done. To the best of our knowledge, only one more case was reported arising in the cerebellopontine angle.

Clinical aspects of photodynamic therapy--Romanian experience.

Photodynamic therapy is an emerging method for local destruction of tissue by generating toxic oxygen species using light absorbed by an administered or an endogenously generated photosensitiser. It is a promising treatment for patients with cancer. More recently it has found increasing use as a method of therapy for non-cancerous illnesses. Following administration of a photosensitiser occurs an accumulation or retention in areas of cancer and disease relative to adjacent normal tissue. The photosensitiser is inactive until irradiated by light, following which cellular destruction occurs. This explanation is a good reason for the scientific and clinical interest in photodynamic therapy.

Similarity solution of temperature structure functions in decaying homogeneous isotropic turbulence.

An equilibrium similarity analysis is applied to the transport equation for <(deltatheta)(2)>, the second-order temperature structure function, for decaying homogeneous isotropic turbulence. A possible solution is that the temperature variance decays as x(n), and that the characteristic length scale, identifiable with the Taylor microscale lambda, or equivalently the Corrsin microscale lambda(theta), varies as x(1/2). The turbulent Reynolds and Péclet numbers decay as x((m+1)/2) when m<-1, where m is the exponent which characterizes the decay of the turbulent energy , viz., approximately x(m). Measurements downstream of a grid-heated mandoline combination show that, like <(deltaq)(2)>, <(deltatheta)(2)> satisfies similarity approximately over a significant range of scales r, when lambda, lambda(theta), , and are used as the normalizing scales. This approximate similarity is exploited to calculate the third-order structure functions. Satisfactory agreement is found between measured and calculated distributions of and , where deltau is the longitudinal velocity increment.