A rare case of extra-intramedullary dorsal tanycitic ependymoma, radically removed with intraoperative neurophysiological monitoring

Introduction: Tanycitic dorsal extra and intramedullary ependymoma is a rare form of tumor. From the histological point of view, these tumors show several aspects that make difficult the differential diagnosis from schwannomas and pilocytic astrocytomas. Tanycytic variant, often occurs in the thoracic tract of the spinal cord, and it is constituted by tanycites, that are typical elongated and bipolar cells that give to the tumor fibrillary aspects. Tanycitic variant has been recently characterized as a variant of ependymoma, since the 2000 World Health Organization (WHO) system. Case presentation: A 57 years old woman presented with intractable back pain often radiating to the left leg. Neurological exam revealed mild weakness in left tight flexion. No sensory or sphincterial disturbances were present. A dorso-lumbar Magnetic Resonance Imaging (MRI)with contrast medium showed a well-demarked T12 intradural extramedullary lesion, suggestive for schwannoma. The tumor was radically removed, with an excellent neurological outcome, and was then characterized as a grade II tanycitic ependymoma. Conclusion: To differentiate the diagnosis between extramedullary ependymomas and schwannomas, meningiomas or astrocytomas is necessary a histopathological examination and a close follow up period is recommended since the tumor could evolve into higher grade. Neurophysiological monitoring is necessary for a satisfactory neurological outcome

A rare case of extra-intramedullary dorsal tanycitic ependymoma, radically removed with intraoperative neurophysiological monitoring

Introduction: Tanycitic dorsal extra and intramedullary ependymoma is a rare form of tumor. From the histological point of view, these tumors show several aspects that make difficult the differential diagnosis from schwannomas and pilocytic astrocytomas. Tanycytic variant, often occurs in the thoracic tract of the spinal cord, and it is constituted by tanycites, that are typical elongated and bipolar cells that give to the tumor fibrillary aspects. Tanycitic variant has been recently characterized as a variant of ependymoma, since the 2000 World Health Organization (WHO) system. Case presentation: A 57 years old woman presented with intractable back pain often radiating to the left leg. Neurological exam revealed mild weakness in left tight flexion. No sensory or sphincterial disturbances were present. A dorso-lumbar Magnetic Resonance Imaging (MRI)with contrast medium showed a well-demarked T12 intradural extramedullary lesion, suggestive for schwannoma. The tumor was radically removed, with an excellent neurological outcome, and was then characterized as a grade II tanycitic ependymoma. Conclusion: To differentiate the diagnosis between extramedullary ependymomas and schwannomas, meningiomas or astrocytomas is necessary a histopathological examination and a close follow up period is recommended since the tumor could evolve into higher grade. Neurophysiological monitoring is necessary for a satisfactory neurological outcome

Case report: Personalized transcatheter approach to mid-aortic syndrome by in vitro simulation on a 3-dimensional printed model

An 8-year-old girl, diagnosed with mid-aortic syndrome (MAS) at the age of 2 months and under antihypertensive therapy, presented with severe systemic hypertension (>200/120 mmHg). Computed tomography (CT) examination revealed aortic aneurysm between severe stenoses at pre- and infra-renal segments, and occlusion of principal splanchnic arteries with peripheral collateral revascularization. Based on CT imaging, preoperative three-dimensional (3D) anatomy was reconstructed to assess aortic dimensions and a dedicated in vitro planning platform was designed to investigate the feasibility of a stenting procedure under fluoroscopic guidance. The in vitro system was designed to incorporate a translucent flexible 3D-printed patient-specific model filled with saline. A covered 8-zig 45-mm-long Cheatham-Platinum (CP) stent and a bare 8-zig, 34-mm-long CP stent were implanted with partial overlap to treat the stenoses (global peak-to-peak pressure gradient > 60 mmHg), excluding the aneurysm and avoiding risk of renal arteries occlusion. Percutaneous procedure was successfully performed with no residual pressure gradient and exactly replicating the strategy tested in vitro. Also, as investigated on the 3D-printed model, additional angioplasty was feasible across the frames of the stent to improve bilateral renal flow. Postoperative systemic pressure significantly reduced (130/70 mmHg) as well as dosage of antihypertensive therapy. This is the first report demonstrating the use of a 3D-printed model to effectively plan percutaneous intervention in a complex pediatric MAS case: taking full advantage of the combined use of a patient-specific 3D model and a dedicated in vitro platform, feasibility of the stenting procedure was successfully tested during pre-procedural assessment. Hence, use of patient-specific 3D-printed models and in vitro dedicated platforms is encouraged to assist pre-procedural planning and personalize treatment, thus enhancing intervention success

A thoracic vertebral localization of a metastasized cutaneous Merkel cell carcinoma: Case report and review of literature

Background: Merkel cell carcinoma (MCC) is a rare neuroendocrine skin tumor, which may be related to sun exposure. It can metastasize to lungs, liver and bone, leading to severe morbidity and mortality. Vertebral metastases from MCC are rare. The authors report the tenth case in the literature, a 59-year-old patient with MCC, which was primarily localized in the scalp, and later provoked distant metastasis to the thoracic spinal column. Case Description: A 59-year-old woman was admitted at our Unit of Neurosurgery with a 4-month history of progressive and severe dorsal back pain, without neurological signs. The patient had been surgically treated for a recidivated MCC in the occipital region in 2007, 2011, and 2013. (In 2013, the surgical treatment also included lateral cervical lymph node dissection). Chemotherapy and radiotherapy had come after the treatments. Magnetic resonance imaging (MRI) of the dorsal spine showed metastatic vertebral involvement with cord impingement of the T7-T8 levels. A total body CT scan revealed lungs and liver metastases, besides vertebral district. After a multidisciplinary consult a palliative surgery was decided and a posterior dorsal approach was employed: Radiofrequency (RF) thermoablation was followed by the injection of cement of T7 and T8 and transpedicle fixation T5-T9. The postoperative course was uneventful and followed by a further adjuvant therapy Conclusion: Spinal metastases from MCC are described in literature only exceptionally. The clinical course is presented, along with a review of literature

Unusual case of dorsal vertebral metastases from a male breast cancer

Introduction: Breast cancer is a malignant neoplasm arising from mammary glands and is a rare entity in the male patient. Spine is a common site for skeletal metastases. Case presentation: A 53-years-old male was admitted to our Neurosurgical unit because of an untreatable dorsal pain. He had been treated 3 years before for breast cancer. A dorsal Magnetic Resonance Imaging (MRI) evidenced pathological masses at T8 level. A total body Computed Tomography (CT) scan revealed lungs and liver metastases. After a multidisciplinary consult, a posterior T8 decompression, a radiofrequency thermoablation in T8 vertebral body followed by screws and rods fixation (T7-T9) was performed. Post-operative course was uneventful and the patient experienced a significant improvement of dorsal pain. Cycles of adjuvant chemo-radiotherapy followed. After 8 months, patient is still alive and in good general conditions but a spine MRI revealed a rapid and widespread diffusion of ostelytic metastases. Conclusion: Despite the high incidence of breast cancer metastases to the spine, very few clinical reports (just eight, whose only one treated surgically) in the literature deal specifically with metastases from male breast cancer, which is rarer and with a worst prognosis than female counterpart. In spite of the poor course, surgery still plays a role in treating these kind of malignancies and in improving quality of life

How to tell a gravastar from a black hole

Gravastars have been recently proposed as potential alternatives to explain the astrophysical phenomenology traditionally associated to black holes, raising the question of whether the two objects can be distinguished at all. Leaving aside the debate about the processes that would lead to the formation of a gravastar and the astronomical evidence in their support, we here address two basic questions: Is a gravastar stable against generic perturbations? If stable, can an observer distinguish it from a black hole of the same mass? To answer these questions we construct a general class of gravastars and determine the conditions they must satisfy in order to exist as equilibrium solutions of the Einstein equations. For such models we perform a systematic stability analysis against axial-perturbations, computing the real and imaginary parts of the eigenfrequencies. Overall, we find that gravastars are stable to axial perturbations, but also that their quasi-normal modes differ from those of a black hole of the same mass and thus can be used to discern, beyond dispute, a gravastar from a black hole.Comment: 16 pages, 13 figures, minor improvemen

Comparison between off-resonance and electron Bernstein waves heating regime in a microwave discharge ion sourcea)

A microwave discharge ion source (MDIS) operating at the Laboratori Nazionali del Sud of INFN, Catania has been used to compare the traditional electron cyclotron resonance (ECR) heating with an innovative mechanisms of plasma ignition based on the electrostatic Bernstein waves (EBW). EBW are obtained via the inner plasma electromagnetic-to-electrostatic wave conversion and they are absorbed by the plasma at cyclotron resonance harmonics. The heating of plasma by means of EBW at particular frequencies enabled us to reach densities much larger than the cutoff ones. Evidences of EBW generation and absorption together with X-ray emissions due to high energy electrons will be shown. A characterization of the discharge heating process in MDISs as a generalization of the ECR heating mechanism by means of ray tracing will be shown in order to highlight the fundamental physical differences between ECR and EBW heating

VIRGO: visualization of A-to-I RNA editing sites in genomic sequences.

RNA Editing is a type of post-transcriptional modification that takes place in the eukaryotes. It alters the sequence of primary RNA transcripts by deleting, inserting or modifying residues. Several forms of RNA editing have been discovered including A-to-I, C-to-U, U-to-C and G-to-A. In recent years, the application of global approaches to the study of A-to-I editing, including high throughput sequencing, has led to important advances. However, in spite of enormous efforts, the real biological mechanism underlying this phenomenon remains unknown.In this work, we present VIRGO (http://atlas.dmi.unict.it/virgo webcite), a web-based tool that maps Ato-G mismatches between genomic and EST sequences as candidate A-to-I editing sites. VIRGO is built on top of a knowledge-base integrating information of genes from UCSC, EST of NCBI, SNPs, DARNED, and Next Generations Sequencing data. The tool is equipped with a user-friendly interface allowing users to analyze genomic sequences in order to identify candidate A-to-I editing sites

Sequence similarity is more relevant than species specificity in probabilistic backtranslation

BACKGROUND: Backtranslation is the process of decoding a sequence of amino acids into the corresponding codons. All synthetic gene design systems include a backtranslation module. The degeneracy of the genetic code makes backtranslation potentially ambiguous since most amino acids are encoded by multiple codons. The common approach to overcome this difficulty is based on imitation of codon usage within the target species. RESULTS: This paper describes EasyBack, a new parameter-free, fully-automated software for backtranslation using Hidden Markov Models. EasyBack is not based on imitation of codon usage within the target species, but instead uses a sequence-similarity criterion. The model is trained with a set of proteins with known cDNA coding sequences, constructed from the input protein by querying the NCBI databases with BLAST. Unlike existing software, the proposed method allows the quality of prediction to be estimated. When tested on a group of proteins that show different degrees of sequence conservation, EasyBack outperforms other published methods in terms of precision. CONCLUSION: The prediction quality of a protein backtranslation methis markedly increased by replacing the criterion of most used codon in the same species with a Hidden Markov Model trained with a set of most similar sequences from all species. Moreover, the proposed method allows the quality of prediction to be estimated probabilistically

Thermal ionization of excitons in V-shaped quantum wires

The exciton-to-free-carrier transition in GaAs and In_xGa_{1-x}As V-shaped quantum wires is revealed by means of temperature-dependent magnetoluminescence experiments. The experimental results are in excellent agreement with the diamagnetic shift obtained from a solution of the full two-dimensional Schrödinger equation for electrons and holes including magnetic-field and excitonic effects. In the GaAs wires, the exciton-to-free-carrier transition is found to occur at temperature consistent with the exciton binding energies. In the In_xGa_{1-x}As wires the diamagnetic shift of the luminescence is found to be free-carrier-like, independent of temperature, due to the weakening of the exciton binding energy induced by the internal piezoelectric field