Endocrown: una alternativa rehabilitadora a las restauraciones rígidas totales clásicas / Endocrown: a rehabilitative alternative to

La restauración ideal en los dientes tratados endodónticamente (DTE) ha sido un tema controversial y ampliamente discutido en la literatura odontológica. El alto índice de fracasos en los dientes endodónticos se asocia principalmente a la falta de un adecuado sellado coronario, motivo por el cual la restauración post endodóntica cumple un papel fundamental. Los propios tejidos del DTE constituyen el refuerzo más importante de la pieza dentaria. La odontología considerada hoy en día como ideal es la mínimamente invasiva. A su vez la restauración de elección deberá ser aquella que respete mayor cantidad de tejido remanente a la hora de seleccionar la restauración coronaria. Se deberá considerar la cantidad y la calidad del remanente dentario sano, como los requisitos funcionales de cada pieza en particular. Si bien existen diversos tipos de restauraciones que podrían rehabilitar un DTE, en este trabajo sólo nos referiremos a las de inserción rígida, específicamente a las endo-onlays, también denominadas endocrowns (AU)

Impacto de la luz operatoria sobre las resinas compuestas: evaluación de su contracción / The impact of operative light on composite resins: evaluation of their shrinkage

El objetivo de este estudio fue analizar el comportamiento, contracción volumétrica, de diferentes resinas compuestas de fotopolimerización, expuestas a variadas condiciones de incidencia lumínica. Se tomaron volúmenes estandarizados de 7 resinas compuestas (microhíbridas y nanohíbridas y nanoparticulados) que se colocaron sobre una línea de referencia en portaobjetos, cubriéndose luego con otro y aplicando una fuerza previamente establecida. Se midió luego con un calibre electrónico la variaciones en el diámetro de la muestra bajo tres situaciones diferentes: luz ambiente (natural), luz foco (halógena), luz artificial (tubos fluorescentes) y sus combinaciones. Resultados: Se observó la mayor variación porcentual al exponer a las muestras simultáneamente a la luz ambiente, artificial y operatoria, siendo los valores más altos de reducción para las resinas compuestas Brilliant NG Coltene (Dentina) y Miris 2 Coltene (Dentina) con -2.52% y -2.7% respectivamente. Conclusión: existieron modificaciones en el volumen de todos los materiales expuestos a las diferentes condiciones de luz y tiempo de exposición. Comparando los resultados con el estudio previo (2007) se pude inferir que los materiales usados en el presente estudio resultaron más fotosensibles, dado que a similar exposición, aumentaron y/redujeron su tamaño en mayor medida (AU)

Prognostic grading after complete resection for thymic malignancies.

OBJECTIVE: Despite the World Health Organization (WHO) and Masaoka classifications have been widely accepted as the main describers of prognosis determinants in thymic malignancies, so far, these have been considered independently from one another. We have reviewed our single-centre 40-year results after surgical treatment of thymic malignancies evaluating the inter-relationships between the clinical, surgical and pathological variables and investigating their prognostic impact in completely resected patients. PATIENTS AND METHODS: A surgical series of 347 patients was reviewed and, of these, 305 with complete resection enrolled. Long-term and disease-free survival (LTS, DFS) analyses were performed. Kaplan-Meir curves for WHO histotypes and Masaoka-stages were inspected and matched with the log-rank test; the Cox regression analysis was adopted in a multivariable approach. RESULTS: Considered independently, the WHO-histotypes did not differentiate clearly from one to another in terms of LTS and DFS; however, types A-AB-B1-B2 and B3-C clustered in 2, statistically different, malignancy groups (LTS, DFS: Cox-p < 0.001). Masaoka staging was confirmed to be a relevant prognostic determinant, even if no evident difference between stages I vs II and stages III vs IV emerged when the Masaoka-classification was factored in. Thus, when investigating 13 surgical and pathological factors of invasiveness, these showed a clustering in 2 groups according to the presence/absence of pathological proven infiltration in the peri-thymic structures (LTS, DFS: Cox-p < 0.001). By matching the WHO-malignancy clusters and infiltration clusters, 4 classes may be identified, which proved to have a distinct prognostic significance: (LTS-Cox: stage-I vs stage-II, p = 0.003; III: p < 0.001, IV: p < 0.001; DFS-Cox: stage-I vs stage-II, p < 0.001; III: p < 0.001; IV: p < 0.001). CONCLUSIONS: When analyzing the long-term outcome of patients underwent complete resection for thymic malignancies, the combination between pathological and surgical variables showed accurate prognosis predictability.

Double pituitary adenomas.

Double pituitary adenomas represent up to 2.6 % of pituitary adenomas in large surgical series and up to 3.3 % of patients with Cushing's disease have been found to have double or multiple pituitary adenomas. We report the case of a 60-year-old male patient whose medical history began in 2002 with erectile dysfunction; hyperprolactinemia was found and MRI showed a 6-mm area of delayed enhancement in the lateral portion of the right pituitary lobe. Treatment with cabergoline was started with normalization of prolactin levels; the following MRI, performed in 2005 and 2008, showed shrinkage of the pituitary lesion. In 2005, the patient began to manifest weight gain, hypertension, and facial plethora, but no further evaluations were done. In January 2010, the patient came to our attention and underwent multiple tests that suggested Cushing's disease. A new MRI was negative. Bilateral inferior petrosal sinus sampling showed significant pituitary-to-peripheral ratio and, in May 2010, the patient underwent exploratory pituitary surgery with evidence of a 1-2-mm white-coloured midline area compatible with pituitary adenoma that was surgically removed. Post-operatively, the patient's clinical conditions improved with onset of secondary hypoadrenalism. The histologic examination confirmed a pituitary adenoma (immunostaining was found to be positive for ACTH and negative for prolactin). We report the case of an ACTH-producing microadenoma metachronous to a prolactin secreting microadenoma although not confirmed histologically, shrunk by medical treatment. A review of data in the literature regarding double or multiple pituitary adenomas has also been done.

GNA11 and N-RAS mutations: alternatives for MAPK pathway activating GNAQ mutations in primary melanocytic tumours of the central nervous system.

AIM: Primary melanocytic tumours are uncommon neoplasms of the central nervous system. Although similarities with uveal melanomas have been hypothesized, data on their molecular features are limited. METHODS: In this study, we investigated the mutational status of BRAF(V600E) , KIT, GNAQ, GNA11, N-RAS and H-RAS in a series of 19 primary melanocytic tumours of the central nervous system (CNS). RESULTS: We identified six cases harbouring mutations in the hotspot codon 209 of the GNAQ gene and two cases with mutations in the hotspot codon 209 of the GNA11 gene. Two mutations in codon 61 of N-RAS were also found. In the single strand conformation polymorphism (SSCP) analysis, no shifts corresponding to BRAF(V600E) mutations or suggesting activating mutations in the KIT gene were observed. CONCLUSIONS: In primary melanocytic tumours of the CNS, GNA11 and N-RAS mutations represent a mechanism of MAPK pathway activation alternative to the common GNAQ mutations. On the other hand, BRAF(V600E) mutations and activating KIT mutations seem to be absent or very rare in these tumours.

TP53, ß-Catenin and c-myc/N-myc status in embryonal tumours with ependymoblastic rosettes.

BACKGROUND: The primitive neuroectodermal tumours of central nervous system (CNS-PNET) are a heterogeneous group of neoplasms, occurring in the CNS and composed of undifferentiated or poorly differentiated neuroepithelial cells which may display divergent differentiation along neuronal, astrocytic and ependymal lines. The WHO classification includes in this group of tumours also ependymoblastomas and medulloepitheliomas. Several groups have reported examples of CNS-PNET with combined histological features of ependymoblastoma and neuroblastoma, defined as 'embryonal tumour with abundant neuropil and true rosettes'. The presence of the amplification of chromosome region 19q13.42, common in both ependymoblastoma and embryonal tumour with abundant neuropil and true rosettes, suggests that they represent a histological spectrum of a single biological entity. METHODS: We examined 24 cases of ependymoblastoma/embryonal tumour with abundant neuropil and true rosettes (EPBL/ETANTR) for the presence of mutations of TP53 and ß-Catenin and for amplification of c-myc/N-myc. RESULTS: The single strand conformation polymorphism-mutational screening did not identify any mutation in exons 5 to 8 of the TP53 gene. However, we found a point mutation affecting codon 34 (GGA → GTA) of ß-Catenin gene resulting in a Glycine → Valine substitution. No cases presented c-myc/N-myc amplification. CONCLUSIONS: EPBL/ETANTRs show molecular features different from other CNS-PNET and medulloblastomas. The presence of alterations in the ß-Catenin/WNT pathway seems to be noteworthy due to the close relationship between this pathway and miR-520g encoded in chromosome 19q13.42 region amplified in these tumours.

Gastrointestinal amyloidosis: a case of chronic diarrhoea.

Amyloidosis is a rare disease caused by extracellular deposits of insoluble fibrillar proteins in various organs and tissues. There are different forms of amyloidosis distinguished by the type of protein fibrils, by the sites of deposition and by associated conditions. Gastrointestinal involvement is common both in primary and secondary amyloidosis, while isolated gastrointestinal amyloidosis is rare. We describe a case of AL amyloidosis with a gastrointestinal involvement and restrictive cardiomiopathy. A 64 year old woman came to our attention with a history of chronic diarrhoea and weight loss, associated with dysphagia, dry mouth, xerophtalmia, chronic gastritis and depression. Clinical diagnosis has been difficult because of aspecificity of symptoms that mimed other more common diseases, like gastro-paresis, epigastric discomfort, gastric or duodenal ulcers, perforation, malabsorption, intestinal pseudo-obstruction. There is an important risk of misunderstanding and diagnostic delay. Indeed in this patient a diagnosis of irritable colon syndrome was erroneously established two years before admission in our hospital. Therefore gastrointestinal amyloidosis should be considered among differential diagnoses of chronic diarrhoea and weight loss when other more common diseases have been excluded.

Morphological and functional MR imaging of Lhermitte-Duclos disease with pathology correlate.

Lhermitte-Duclos disease (LDD) is a rare benign lesion of uncertain pathogenesis characterised by distortion of the normal cerebellar laminar cytoarchitecture. We report a case of LDD thoroughly characterized by advanced magnetic resonance imaging techniques, with diffusion-weighted, perfusion-weighted and post-gadolinium sequences. Imaging showed restricted diffusion consistent with high cellularity, high degree of vascularity and preserved blood-brain barrier permeability, correlating with pathology.

Prognostic significance of the Ki-67 labeling index in growth hormone-secreting pituitary adenomas.

CONTEXT: Ki-67 is a marker of proliferation activity associated with invasiveness and prognosis in human tumors. OBJECTIVE: The aim of the study was to evaluate the Ki-67 index prognostic relevance in a group of acromegalic patients who underwent transsphenoidal surgery for a GH-secreting pituitary adenoma. MATERIAL AND METHODS: We selected 68 consecutive acromegalic patients referred to our hospital during a 5-yr period. The Ki-67 index was determined by immunohistochemistry on tissue samples obtained from each adenoma after surgery. Those patients who were not completely cured after surgery began medical therapy with somatostatin analogs (SSAs). Periodical pituitary magnetic resonance imaging and hormonal evaluation were performed during the follow-up. RESULTS: Twenty-eight of 68 patients were cured after surgery (41%). Among the 40 patients treated with SSAs, 13 were considered uncontrolled. Pituitary magnetic resonance imaging showed residual/recurrent disease in 25 of 68 patients after 6 months. No correlation was found between Ki-67 index and age, tumor size, GH, or IGF-I plasma levels. Tumors described as having cavernous sinus invasion had a higher mean Ki-67 index as compared with noninvasive tumors (P < 0.01). The Ki-67 index was significantly lower in tumors in patients cured after surgery as compared with patients considered not cured (P < 0.01) and in tumors in patients controlled by SSA therapy as compared with patients considered as uncontrolled (P < 0.05). CONCLUSION: The Ki-67 labeling index may predict clinical outcome in postsurgical management of acromegalic patients. We suggest routine Ki-67 evaluation in GH-secreting pituitary adenomas.

Intracranial meningiomas associated with non-traumatic chronic subdural hematoma.

BACKGROUND: Non-traumatic subdural hematomas are very rarely associated with intracranial meningiomas. Pathophysiological mechanisms of such an association are not yet fully understood. CASE DESCRIPTION: We report on two patients harboring an intracranial meningioma and ipsilateral non-traumatic chronic subdural hematoma. Their history was negative for risk factors for subdural hematoma. Both patients were submitted to surgery for evacuation of the subdural collection. The presence of the meningioma was discovered during surgery. A second operation was necessary in our first case. CONCLUSIONS: We retrospectively analyzed our radiological data and the literature to provide some features that may help in the pre-operative diagnosis of a meningioma in patients presenting with a chronic subdural hematoma. Furthermore the mechanisms responsible for this association are discussed on the basis of our pathological evidence.

S100A13, a new marker of angiogenesis in human astrocytic gliomas.

S100 proteins are Ca(2+)-binding polypeptides involved in the tumourigenesis of several human neoplasms. S100A13 is a key regulator of the stress-dependent release of FGF1, the prototype of the FGF protein family involved in angiogenesis. Indeed, S100A13 is a copper binding protein able to enhance the export of FGF1 in response to stress in vitro and to induce the formation of a multiprotein aggregate responsible for FGF1 release. We investigated the expression of S100A13 in human astrocytic gliomas in relation to tumour grading and vascularization. A series of 26 astrocytic gliomas was studied to evaluate microvessel density and to assess FGF1, S100A13 and VEGF-A expression. FGF1 was equally expressed in the vast majority of tumours, whereas S100A13 and VEGF-A were significantly up-regulated in high-grade vascularized gliomas. Moreover, both S100A13 and VEGF-A expression significantly correlated with microvessel density and tumour grading. These data suggest that the up-regulation of S100A13 and VEGF-A expression correlates with the activation of angiogenesis in high-grade human astrocytic gliomas.

Dual role of beta-carotene in combination with cigarette smoke aqueous extract on the formation of mutagenic lipid peroxidation products in lung membranes: dependence on pO2.

Results from some intervention trials indicated that supplemental beta-carotene enhanced lung cancer incidence and mortality in chronic smokers. The aim of this study was to verify the hypothesis that high concentrations of the carotenoid, under the pO2 present in lung (100-150 mmHg), may exert deleterious effects through a prooxidant mechanism. To test this hypothesis, we examined the interactions of beta-carotene and cigarette smoke condensate (tar) on the formation of lipid peroxidation products in rat lung microsomal membranes enriched in vitro with varying beta-carotene concentrations (from 1 to 10 nmol/mg prot) and then incubated with tar (6-25 microg/ml) under different pO2. As markers of lipid peroxidation, we evaluated the levels of conjugated dienes and malondialdehyde, possessing mutagenic and pro-carcinogenic activity. The exposure of microsomal membranes to tar induced a dose-dependent enhancement of lipid peroxidation, which progressively increased as a function of pO2. Under a low pO2 (15 mmHg), beta-carotene acted clearly as an antioxidant, inhibiting tar-induced lipid peroxidation. However, the carotenoid progressively lost its antioxidant efficiency by increasing pO2 (50-100 mmHg) and acted as a prooxidant at pO2 ranging from 100 to 760 mmHg in a dose-dependent manner. Consistent with this finding, the addition of alpha-tocopherol (25 microM) prevented the prooxidant effects of the carotenoid. beta-Carotene auto-oxidation, measured as formation of 5,6-epoxy-beta,beta-carotene, was faster at high than at low pO2 and the carotenoid was more rapidly consumed in the presence of tar. These data point out that the carotenoid may enhance cigarette smoke-induced oxidative stress and exert potential deleterious effects at the pO2 normally present in lung tissue.

Effects of cyclo-oxygenase inhibition on exhaled eicosanoids in patients with COPD.

BACKGROUND: Leukotriene (LT) B4 concentrations are increased and prostaglandin (PG) E2 concentrations are decreased in exhaled breath condensate (EBC) in patients with chronic obstructive pulmonary disease (COPD). A study was undertaken to investigate the short term effects of cyclo-oxygenase (COX) inhibition on exhaled LTB4 and PGE2 concentrations in patients with COPD and to identify the COX isoform responsible for exhaled PGE2 production. METHODS: Two studies were performed. A double blind, crossover, randomised, placebo controlled study with ibuprofen (400 mg qid for 2 days), a non-selective COX inhibitor, was undertaken in 14 patients with stable COPD, and an open label study with oral rofecoxib (25 mg once a day for 5 days), a selective COX-2 inhibitor, was undertaken in a different group of 16 COPD patients. EBC was collected before and after drug treatment. Exhaled LTB4 and PGE2 concentrations were measured with specific immunoassays. RESULTS: All patients complied with treatment as indicated by a reduction in ex vivo serum thromboxane B2 concentrations (ibuprofen) and a reduction in lipopolysaccharide induced increase in ex vivo plasma PGE2 values (rofecoxib) of more than 80%. Exhaled LTB4 was increased after ibuprofen (median 175.5 (interquartile range 128.8-231.5) pg/ml v 84.0 (70.0-98.5) pg/ml, p < 0.001) and exhaled PGE2 was reduced (93.5 (84.0-105-5) pg/ml v 22.0 (15.0-25.5) pg/ml, p < 0.0001). Rofecoxib had no effect on exhaled LTB4 (p = 0.53) or PGE2 (p = 0.23). CONCLUSIONS: Non-selective COX inhibition decreases PGE2 and increases LTB4 in EBC, whereas selective COX-2 inhibition has no effect on these eicosanoids. PGE2 in EBC is primarily derived from COX-1 activity, and COX inhibition may redirect arachidonic acid metabolism towards the 5-lipoxygenase pathway.

Thymus changes in anti-MuSK-positive and -negative myasthenia gravis.

Morphologic findings of thymuses from 32 anti-acetylcholine receptor (AChR)-negative myasthenia gravis patients, 12 with and 20 without antibodies against the muscle-specific kinase (MuSK), were compared with those from 30 AChR-positive subjects. In contrast with the high frequency of thymic hyperplastic changes in AChR-positive patients, in MuSK-positive subjects histologic alterations were minimal, arguing against an intrathymic disease pathogenesis. Since hyperplastic changes were seen in 35% of MuSK-negative patients, the thymus could be involved in some of these cases.

Rosette-forming glioneuronal tumour of the fourth ventricle: report of a case with clinical and surgical implications.

A 32-year-old woman presented with a 2-month history of episodic headache, cervical pain and neck rigidity. Neurological examination showed a moderate dysmetria. Magnetic resonance imaging (MRI) revealed a mass occupying the fourth ventricle. The patient underwent median sub-occipital craniotomy with total excision of the lesion well demarcated except for a portion infiltrating the right side of the IV ventricle wall. In the post-operative course the patient developed VI and VII right cranial nerves palsy and worsening of dysmetria. MRI confirmed the complete removal of the tumour without signs of recurrence. The pathological diagnosis was rosette forming glio-neuronal tumour (RGNT). At present this is the 13th RGNT reported in literature. These lesions are considered low-grade tumours (WHO I). Nevertheless, the case here reported, like in 6 of the 12 cases in literature, developed disabling post-operative deficits. To establish the therapeutic choice long-term follow-up studies are needed.