Tratamiento de schwanomas vestibulares esporádicos mediante radiocirugía: estudio prospectivo de cohorte / Radiosurgical treatment of sporadic vestibular schwannomas: a prospective cohort study

Objetivo: Analizar los resultados iniciales de un estudio prospectivo en pacientes con schwanomas vestibulares tratados con radiocirugía en la Pontificia Universidad Católica de Chile. Material y método: Se presentan 17 pacientes portadores de schwanomas vestibularesesporádicos tratados con radiocirugía y seguidos entre 6 y 26 meses. El tratamiento fue realizado con acelerador lineal Varian clinac 21 EX, con equipamiento Varian-Zmed. La dosismarginal administrada al tumor fue de 12 a 12,5 Gray. El seguimiento a 6, 12 y 24 meses consta de resonancia magnética, audiometría y evaluación clínica. Resultados: La dosis marginal de irradiación usada fue entre 12 y 12,5 Gray normalizada a la isodosis 70% u 80%. En todos los pacientes se documentó disminución de la captación de contraste del tumor y en 16 (94%) se observaron áreas de necrosis centro tumoral. No hubo mortalidad, la preservación de audición útil fue 62,5% actuarial a 2 años. No ha existido deterioro de la función de los nervios facial ni trigémino. Todos los pacientes que previamente estaban trabajando retornaron a sus labores en promedio 11,5 días luego del tratamiento. Conclusiones: Los resultados iniciales de esta serie son comparables a los resultados publicados en la literatura y refuerzan el demostrado rol de la radiocirugía en el tratamiento de los schwanomas vestibulares.

Objective: To analyze the preliminary experience of radiosurgery for VestibularSchwannomas at the Pontificia Universidad Católica de Chile. Material and methods: The first 17 patients with sporadic Vestibular Schwannomas treated by radiosurgery at our institution are reported. The marginal dose used was 12 to 12.5 Gy. prescribed at the 70 or 80 isodose line. Patients were controlled at 6, 12 and24 months with magnetic resonance, audiometric study and clinical examination. Results: In all of the 17 patients treated a decrease tumor enhancement on MR was demonstrated. In 16 patients (94%) a pattern of central tumor necrosis was observedduring the firs year. Actuarial useful hearing was maintained in 62.5% at 2 year after treatment. Facial nerve function was maintained in all of the 15 patients with normal function at treatment (100%). Trigeminal function was maintained in all of the 14 patients (100%) with previous normal trigeminal function. The mean time to return to work or normal activities was 11.5 days after treatment Conclusions: These preliminary results are comparable with results published in theliterature and reinforce the demonstrate role of radiosurgery in the management of vestibular schwannomas.

[Experience feed back committee in radiotherapy (CREx): a compulsory tool for security management evaluation at two years]. / La cellule de retour d'expérience (CREx) en radiothérapie: un outil indispensable au management de la sécurité. Une évaluation après deux ans d'activité au centre Oscar-Lambret.

After working on treatment organisation in radiotherapy (bonne pratiques organisationnelles en radiothérapie - action pilote MEAH 2003), the development of a security policy has become crucial. With the help of Air France Consulting and the MEAH, three cancer centers in Angers, Lille and Villejuif worked together on the implantation of experience feed back committees (CREx) dedicated to the registration, analysis and correction of precursor events. After two years, we report the centre Oscar-Lambret experience in Lille and try to get the recommendations for generalisation of the process. This seems now to be compulsory for security management in oncology.

Complicaciones de rinosinusitis aguda en niños del Hospital Sótero del Río / Complications of acute rhinosinusitis in children at Sótero del Río Hospital

Introducción: La rinosonusitis aguda (RSA) es frecuente en niños, respondiendo bien a tratamiento médico en la mayoría de los casos. Sin embargo puede presentar complicaciones graves a nivel orbitario e intracerebral. Objetivo: Evaluaria frecuencia, describirias características clínicas, evaluare! tratamiento y evolución de la rinosinusitis aguda complicada, en niños del Hospital Sótero del Río. Material y método: Estudio retrospectivo-descriptivo realizado en el Hospital Sótero del Río, utilizando fichas clínicas de pacientes ingresados desde enero de 2002 hasta julio de 2007, con diagnóstico de RSA complicada. Resultados: Se incluyeron 27 pacientes con diagnóstico presuntivo de RSA complicada: 30 por ciento con celulitis preseptal aislada, 36 por ciento celulitis postseptal, 26 por ciento absceso subperióstico y 8 por ciento complicaciones intracraneales. La edad promedio fue 4.53 años (4 meses-13 años); 56 por ciento sexo masculino y 44 por ciento sexo femenino; promedio de días hospitalizados 7,24 días (2-19 días); total de días con tratamiento antibiótico 20,2 días (9-38 días); el cultivo microbiológico fue positivo en 25 por ciento de los pacientes con tratamiento quirúrgico (Staphylococcus epidermidis). No existió compromiso visual al alta en ninguno de los pacientes. Conclusión: La complicación más frecuente de RSA fue la orbitaria (92 por ciento) similar a lo descrito en la literatura. El seno etmoidal, maxilar y frontal fueron frecuentemente comprometidos. La edad de presentación de complicación de RSA fue levemente menor a lo descrito en la literatura. Se encontró predominio del género masculino, aunque en los abscesos subperiósticos predominó el sexo femenino. No se encontró relación directa entre la gravedad de RSA y los valores de proteína C reactiva (PCR) y leucocitosis. La mayoría de los abscesos subperiósticos se manejaron médicamente, teniendo la mitad de ellos más de 9 años. Sólo un paciente presentó complicación orbitaria y encefálica...

Introduction: Acute rhinosinusitis (RSA) is frequent in children. Although in most cases responds well to medical treatment, it could result in serious orbital and intracranial complications. Aim: To assess the frequency, describe the clinical characteristics and evaluate treatment and evolution of acute rhinosinusitis in children at Sótero del Rio hospital. Material and Method: Retrospective - descriptive study of clinical data from Sótero del Rio hospital between Jan 2002 and July 2007, involving patients with a diagnosis of complicated RSA. Results: Data from 27 patients were included in this study, all with presumptive RSA complications: 30 percent had isolated preseptal cellulitis, 36 percent had postseptal cellulitis, 26 percent had subperiostal abscesses, and 8 percent had intracranial complications. The average age of patients was 4,53 years (4 months-13 years old); 56 percent were males and 44 percent were females; hospitalization was in average 7,24 days (2 -19 days), the average number of days on antibiotic treatment was 20,2 (9 -38 days); microbiologic culture was positive in 25 percent of patients with surgical treatment (Staphylococcus epidermidis). None of the patients had visual complications when they were discharged from the hospital. Conclusion: The most frequent RSA complication was orbital (92 percent of complications), similar to what is reported in the literature. Ethmoidal, maxilar and frontal sinuses were more often involved. RSA complications presented at a slightly younger age than reported in the literature. More often males were affected, but subperiostal abscesses were more common in females. There was no direct relation between RSA seriousness and C-reactive protein or leukocitosis. Most subperiostal abscesses were medically treated; more than half of these patients were older than 9 years old. Only one patient presented both orbital and intracranial complications

Lipomas en conducto auditivo interno: experiencia clínica y revisión del tema / Internal auditory canal lipomas: clinical experience and literature review

Se presentan dos casos clínicos del Departamento de Otorrinolaringología de la Pontificia Universidad Católica de Chile, con diagnóstico de lipoma del conducto auditivo interno (CAí). Los lipomas del CAí son neoplasias benignas poco frecuentes, con una frecuencia de 0,15 por ciento de los tumores del CAL Se presentan principalmente entre la tercera y quinta década de la vida, en su mayoría hombres caucásicos. Clínica y audiológicamente son indistinguibles de otros tumores de la misma zona, siendo el neurinoma del acústico (schwanoma vestibular) el tumor más frecuente en el CAí (90 por ciento). Las Imágenes de resonancia magnética permiten realizar el diagnóstico específico de lipoma. El tratamiento quirúrgico ha sido desplazado por el manejo conservador, dado que los lipomas tienen crecimiento lento, sin trasformación maligna, en general, junto con difícil técnica quirúrgica por infiltración a estructuras adyacentes. Sólo estaría indicada la cirugía en casos que exista crecimiento tumoral durante el seguimiento o en pacientes con síntomas intensos y progresivos.

Two case reports with diagnosis of internal auditory canal lipomas are presented. Lipomas of the internal auditory canal are benign neoplasms, making up 0.15 percent of all tumors in this area. They occur more frequently in the third to fifth decade of life predominantly in Caucasian males. The are clinically and audiologically indistinguishable from other tumors in this region, with eighth cranial nerve schwannomas (vestibular schwannomas) being the most common I AC tumor (90 percent). MRI findings allow for specific diagnosis of a lipoma. Regarding treatment, surgery has been displaced by a conservative treatment of this rare lesion. Lipomas are slow growth lesions, without malignant transformation, and with inherent difficulties to their removal because of the adipose tissue infiltrating the nerve, as well as only partial resolution of symptoms in most cases. Surgery could only be indicated when relevant and disabling symptoms are present.

p53-dependent inhibition of mammalian cell survival by a genetically selected peptide aptamer that targets the regulatory subunit of protein kinase CK2.

Based on the perturbation of its expression in human cancers and on its involvement in transformation and tumorigenesis, protein kinase CK2 has recently attracted attention as a potential therapeutic target. To assess the value of CK2 as a target for antiproliferative strategies, we have initiated a program aiming to develop inhibitors targeting specifically the regulatory CK2beta subunit. Here, we use a two-hybrid approach to isolate from combinatorial libraries, peptide aptamers that specifically interact with CK2beta. One of these (P1), which has significant sequence homology to the cytomegalovirus IE2 protein, binds with high affinity to the N-terminal domain of CK2beta without disrupting the formation of the CK2 holoenzyme. Expression of green fluorescent protein (GFP)-P1 in different mammalian cell lines activates p53 phosphorylation on serine 15, induces an upregulation of p21 and the release of the Cyt-C and apoptosis-inducing factor proapoptotic proteins triggering caspase-dependent and caspase-independent apoptosis. GFP-P1-induced apoptosis is associated with a p53-dependent pathway as cell death was abrogated in p53 knocked out cells. In summary, our data show that genetically selected peptide aptamers that specifically target CK2beta can induce apoptosis in mammalian cells through the recruitment of a p53-dependent apoptosis pathway. They also emphasize the critical role of CK2beta for cell survival and might allow the design of novel proapoptotic agents targeting this protein.

Conformation, localization, and integrin binding of talin depend on its interaction with phosphoinositides.

Talin is a structural component of focal adhesion sites and is thought to be engaged in multiple protein interactions at the cytoplasmic face of cell/matrix contacts. Talin is a major link between integrin and the actin cytoskeleton and was shown to play an important role in focal adhesion assembly. Consistent with the view that talin must be activated at these sites, we found that phosphatidylinositol 4-monophosphate and phosphatidylinositol 4,5-bisphosphate (PI4,5P(2)) bound to talin in cells in suspension or at early stages of adhesion, respectively. When phosphoinositides were associated with phospholipid bilayer, talin/phosphoinositide association was restricted to PI4,5P(2). This association led to a conformational change of the protein. Moreover, the interaction between integrin and talin was greatly enhanced by PI4,5P(2)-induced talin activation. Finally, sequestration of PI4,5P(2) by a specific pleckstrin homology domain confirms that PI4,5P(2) is necessary for proper membrane localization of talin and that this localization is essential for the maintenance of focal adhesions. Our results support a model in which PI4,5P(2) exposes the integrin-binding site on talin. We propose that PI4,5P(2)-dependent signaling modulates assembly of focal adhesions by regulating integrin-talin complexes. These results demonstrate that activation of the integrin-binding activity of talin requires not only integrin engagement to the extracellular matrix but also the binding of PI4,5P(2) to talin, suggesting a possible role of lipid metabolism in organizing the sequential assembly of focal adhesion components.

Visualization and molecular analysis of nuclear import of protein kinase CK2 subunits in living cells.

We have generated fusion proteins between the subunits of CK2 and GFP and characterized their behaviour in living cells. The expressed fusion proteins were functional and interacted with endogenous CK2. Imaging of NIH3T3 cells expressing low level of GFP-CK2alpha or GFP-CK2beta showed that both proteins were mostly nuclear in interphase. Both CK2 subunits contain nuclear localization domains that target them independently to the nucleus. Once in the nucleus, both subunits diffused rapidly in the nucleoplasm. In mitotic cells, CK2 subunits were dispersed throughout the cytoplasm and were not associated to chromatin. Our data are compatible with the idea that each subunit can translocate individually to the nucleus to interact with each other or with important cellular partners. Understanding the molecular mechanisms which regulate the dynamic localization of CK2 subunits will be of central importance.

Expression of E-, P-, n-cadherins and catenins in human bladder carcinoma cell lines.

PURPOSE: Cadherins are cell surface glycoproteins that mediate Ca2+-dependent, homophilic cell-cell adhesion. The classical cadherins, E-, P- and N-cadherins, are known to self-associate from their extracellular domain, while their cytoplasmic domain interacts with either beta-catenin or plakoglobin (gamma-catenin), which in turn is bound to alpha-catenin that links the complex to the actin cytoskeleton. The aim of the present study was to analyze the expression of E-, P- and N-cadherins and catenins in human bladder carcinoma cells. MATERIALS AND METHODS: Five human bladder carcinoma cell lines, representing a variety of differentiation states, were grown in cell culture. We performed a cell aggregation assay, specific for biological cadherin activity. The expression of cadherins and catenins was analyzed by immunocytochemistry, Western blotting and RT-PCR. The interactions between cadherins and catenins were assessed by immunoprecipitation. RESULTS: We observed a reduced E-cadherin expression in the poorly differentiated and invasive-tumor derived cells. Interestingly, immunofluorescence study reveals the persistent localization of catenins at intercellular contacts in two E-cadherin deficient cell lines (T24 and TCCSUP) which yet exhibit an epithelial-like morphology and a calcium-dependent adhesive capacity. This suggests that other cadherin(s) are expressed in these both cell lines. P-cadherin, another epithelial cadherin, is expressed only in E-cadherin positive cells. On the other hand, N-cadherin is present at cell-cell borders in the very anaplastic cell lines, T24 and TCCSUP, and is able to link beta-catenin or plakoglobin. CONCLUSION: These results indicate that N-cadherin may participate in intercellular adhesion, while facilitating bladder tumorigenesis.

Talin controls the exit of the integrin alpha 5 beta 1 from an early compartment of the secretory pathway.

Talin is a major cytosolic protein that links the intracellular domains of beta1 and beta3 integrins to the cytoskeleton. It is required for focal adhesion assembly. However, its downregulation not only slows down cell spreading and organization of focal adhesions but also impairs the maturation of some beta1 integrins, including the fibronectin receptor alpha5beta1. To investigate this, we characterized the beta1 integrin synthesized in cells expressing talin anti-sense RNA (AT22 cells). We identified a large intracellular pool of beta1 integrins that is abnormally accumulated in an earlier compartment of the secretory pathway. In this report, we show that in talin-deficient AT22 cells, the aberrant glycosylation of integrin receptors is accompanied by a delay in the export of the integrin alpha5beta1. In normal cells, talin was found associated with beta1 integrins in an enriched membrane fraction containing Golgi and endoplasmic reticulum. Finally, microinjection of anti-talin antibodies resulted in accumulation of the integrins within the cells. These data strongly suggest that talin plays a specific role in the export of newly synthesized integrins. We propose that talin binding to the integrin may disclose a diphenylalanine export signal, which is present in the membrane-proximal GFFKR motif conserved in all integrin alpha chains.

Lipid products of phosphoinositide 3-kinase and phosphatidylinositol 4',5'-bisphosphate are both required for ADP-dependent platelet spreading.

We have shown previously that ADP released upon platelet adhesion mediated by alphaIIb beta3 integrin triggers accumulation of phosphatidylinositol 3',4'-bisphosphate (PtdIns-3,4-P2) (Gironcel, D. , Racaud-Sultan, C., Payrastre, B., Haricot, M., Borchert, G., Kieffer, N., Breton, M., and Chap, H. (1996) FEBS Lett. 389, 253-256). ADP has also been involved in platelet spreading. Therefore, in order to study a possible role of phosphoinositide 3-kinase in platelet morphological changes following adhesion, human platelets were pretreated with specific phosphoinositide 3-kinase inhibitors LY294002 and wortmannin. Under conditions where PtdIns-3, 4-P2 synthesis was totally inhibited (25 microM LY294002 or 100 nM wortmannin), platelets adhered to the fibrinogen matrix, extended pseudopodia, but did not spread. Moreover, addition of ADP to the medium did not reverse the inhibitory effects of phosphoinositide 3-kinase inhibitors on platelet spreading. Although synthetic dipalmitoyl PtdIns-3,4-P2 and dipalmitoyl phosphatidylinositol 3',4', 5'-trisphosphate restored only partially platelet spreading, phosphatidylinositol 4',5'-bisphosphate (PtdIns-4,5-P2) was able to trigger full spreading of wortmannin-treated adherent platelets. Following 32P labeling of intact platelets, the recovery of [32P]PtdIns-4,5-P2 in anti-talin immunoprecipitates from adherent platelets was found to be decreased upon treatment by wortmannin. These results suggest that the lipid products of phosphoinositide 3-kinase are required but not sufficient for ADP-induced spreading of adherent platelets and that PtdIns-4,5-P2 could be a downstream messenger of this signaling pathway.

De novo methylation of tumour suppressor genes CDKN2A and CDKN2B is a rare finding in B-cell chronic lymphocytic leukaemia.

De novo methylation of the 5'CpG island has been recently reported as an alternative mechanism of inactivation for the tumour suppressor genes CDKN2A and CDKN2B. We examined CDKN2A methylation status at diagnosis in 42 B-cell chronic lymphocytic leukaemia (CLL) patients, in 19 cases the CDKN2B methylation status was also analysed. No homozygous CDKN2A/2B deletion was detected, but four patients (9%) displayed an aberrant CDKN2A methylation status and only one had hypermethylated CDKN2B. De novo methylation was associated with silencing of gene expression. These results confirm that CDKN2A/2B inactivation by deletion is a rare event in CLL and suggest that aberrant methylation could be an alternative way of inactivation very rarely involved in the development of some CLL.

Isochromosome 7q and trisomy 8 are consistent primary, non-random chromosomal abnormalities associated with hepatosplenic T gamma/delta lymphoma.

Four patients with hepatosplenic T gamma/delta lymphoma, a rare but distinct entity of peripheral T cell lymphoma, are reported on. In each case, cytogenetic studies showed the presence of an Isochromosome 7q and a trisomy 8. A few chromosome studies have previously been reported in this lymphoma subtype but comparison with these published cases confirms that isochromosome 7q and trisomy 8 are primary, non-random chromosomal abnormalities in hepatosplenic T gamma/delta lymphoma.