Edson Oliveira

Rubbing-induced charge domains observed by electrostatic force microscopy: effect on liquid crystal alignment

The rubbing of polymer-coated substrates is one of the most frequently used techniques for liquid crystal alignment. However, the aligning mechanisms are not completely understood. The influence of friction charges induced by the rubbing process has been taken into account in theoretical publications. In this work we investigate the rubbing-induced charge domains of three polymers (PMMA, PI and PVA) with the electrostatic force microscopy technique, which allows the simultaneous determination of the surface topography and electrostatic potential. We observed a large intensity of the potential for the PMMA substrate, whereas no charge domains were observed for PVA. In addition, we followed the time evolution of the surface charge domains, and surprisingly after five days the charges were still present with a small reduction of intesity. Using polarizing optical microscopy we studied the influence of the charge domains on the LC aligning properties.

Liquid crystal alignment on isotropic submicro‐textured surfaces of homeotropic‐planar states

The equilibrium configuration of liquid crystal molecules in contact with a periodicly patterned substrate has been theoretically analysed considering the variation of the order parameter at the interface, and a first order transition was predicted for a critical periodicity, or induced by temperature or an electric field. In this work, we experimentally investigated the equilibrium configuration of the director for a submicron patterned substrate, alternating homeotropic and random planar regions in the substrate. Experimentally, it was possible to access a starting point, theoretically close to the first order transition, however no transition was observed either on varying the temperature or on applying an electric field. The possible reasons for the non‐observation of the phase transition are discussed.

Rayleigh scattering of a new lyotropic nematic liquid crystal system: crossover of propagative and diffusive behaviour

In this paper we present to our knowledge the first light-scattering measurements on a rather new lyotropic system potassium laurate, decylammonium chloride, H2O. Relative concentrations were chosen in order to obtain the discotic ND phase over a large temperature range. Measurements involve digital recording of the autocorrelation function resulting from selfbeating of the depolarized scattered light. They were carried out at a fixed temperature in the ND phase range, by varying the scattering angle. A strong tendency to oscillations, superimposed on the usual relaxation signal, was found. This behaviour is quite surprising, as special precautions had been taken to minimize any eventual propagative signal. Such precautions have been tested previously, while investigating the older system potassium laurate, decanol, D2O. Nevertheless, we have found that in the new lyotropic system, a propagative component may occur in a significant way, or even become dominant for some particular situations. Actually, the characterization of such situations is the main purpose of the present paper. Based upon a detailed analysis of photocorrelation data, it will be shown that the observed behaviour is consistent with the expected wave vector dependences of propagative and diffusive modes. Finally, a discussion is given on possible causes for the tendency to instability of lyotropic nematic liquid crystals.

A purely extradural lumbar nerve root cavernoma mimicking acute myeloid leukemia recurrence: Case report and literature review.

Background: Myeloid sarcoma (MS) is a malignant tumor that usually occurs concomitantly with or following acute myeloid leukemia (AML). Cavernomas are benign congenital malformations that are unusual in the spine and exceedingly rare in pure extradural locations. Case Description: We report a 73-year-old female with a previous medical history of AML in remission for 3 years who presented with symptoms of low back pain and right lower extremity radiculopathy. A magnetic resonance scan showed an extradural, foraminal lesion centered at the L2 level involving the right L2 nerve root. In view of the history of AML, this lesion was potentially considered MS, a form of AML relapse. Surgery consisting of a right L1 and L2 hemilaminectomy facilitated gross total resection of the purely extradural lesion the proved histologically to be a cavernoma. Conclusion: In patients with a history of leukemia, MS must be considered in the differential diagnosis for any epidural or nerve root lesion that appears following treatment. Although rare, cavernomas must be considered among the differential diagnoses for epidural nerve root lesions in the setting of AML.

Atypical teratoid/rhabdoid tumour following craniopharyngioma radiotherapy during childhood.

Dear Editor: This letter reports a rare clinical issue based on the onset of an atypical teratoid/rhabdoid tumour (AT/RT), consequently after radiotherapy. Besides being rare, this is a first report of this event after craniopharyngioma radiotherapy. Craniopharyngioma radiotherapy (RTh) is considered in situations of subtotal surgical excision, performed when there is a high risk of morbidity associated with total resection. Tumour development after RTh is well known and accepted. To the best of our knowledge, this is the third case of an AT/RT after RTh and the first after craniopharyngioma RTh. The case refers to a 22-year-old female patient submitted to 3D conformational RTh (34Gy) at the age of 12 years, after a subtotal surgical removal of a craniopharyngioma. During follow-up, the tumour residue remained stable. She was admitted to the hospital with a 2-days evolution of headaches, nausea and vomiting. Neurological findings showed somnolence with psychomotor slowing but reacting to verbal stimulus, without focal deficits. MRI showed a large sagittal frontal lesion with left frontal extension andmarkedmass effect with heterogeneous contrast enhancement (Fig. 1). Surgery was performed but the tumour was highly vascularized and only a partial removal was possible. At D2 post-operation, a clinical worsening was observed. CT scan showed a bilateral anterior cerebral artery ischemia with intra-tumour haemorrhage. The patient died 4 days after surgery. Neuropathology disclosed a malignant neoplastic tumour, with a high mitotic and proliferative index and areas of geographic necrosis. Immunohistochemical study showed extensive, immunoreactivity for vimentin and epithelial membrane antigen (EMA), polyfocal for neurofilaments, and only focal for glial fibrillary acidic protein (GFAP). INH1 was negative. A diagnosis of AT/RT was done. FISH analysis was performed with several probes for chromosome 22 targeting the SMARCB1/INI1 gene, the PDGFRβ gene, the EWS, HIRA and ARSA genes (Fig. 2). Chromosomal comparative genomic hybridization (CGH) was also performed, and abnormalities were detected by comparing the dynamic standard reference interval to the confidence interval of the mean ration profile of the test samples. CGH analysis revealed a relatively complex karyotype where the chromosomal alterations were observed, namely a deletion involving 22q. AT/RT affects more frequently children less than 3 years old, with only 42 adult cases published so far. Despite aggressive treatment protocols, it has a poor prognosis mainly in children with less than 1-year survival. Our case showed the histological hallmark of this entitywhich are rhabdoid cells with undifferentiated elements with areas of differentiated mesenchymal cells. In immunohistochemical * Edson Oliveira edsoliveira@gmail.com

Corpus callosum and neglect syndrome: Clinical findings after meningioma removal and anatomical review

Two types of neglect are described: hemispatial and motivational neglect syndromes. Neglect syndrome is a neurophysiologic condition characterized by a malfunction in one hemisphere of the brain, resulting in contralateral hemispatial neglect in the absence of sensory loss and the right parietal lobe lesion being the most common anatomical site leading to it. In motivational neglect, the less emotional input is considered from the neglected side where anterior cingulate cortex harbors the most frequent lesions. Nevertheless, there are reports of injuries in the corpus callosum (CC) causing hemispatial neglect syndrome, particularly located in the splenium. It is essential for a neurosurgeon to recognize this clinical syndrome as it can be either a primary manifestation of neurosurgical pathology (tumor, vascular lesion) or as a postoperative iatrogenic clinical finding. The authors report a postoperative hemispatial neglect syndrome after a falcotentorial meningioma removal that recovered 10 months after surgery and performs a clinical, anatomical, and histological review centered in CC as key agent in neglect syndrome.

Adult pilocytic astrocytoma of conus medullaris: clinical considerations and review of the literature

Astrocytomas are responsible for 30% of all primitive intramedullary tumors with cervicothoracic predominance. However, only about one hundred cases of intramedullary pilocytic astrocytomas were described. The authors described the case of a 69 year-old patient presenting with a broad-base gait, bilateral pain and dysesthesia of inferior limbs with a diagnosis of an intra-axial cystic lesion centered to the conus medullaris, diagnosed as pilocytic astrocytoma of conus medullaris (PACM) after surgery. To the best of our knowledge, only two previous reports concerning PACM were made. As benign lesions associated with long survivals, function should be the mainstay of treatment of PACM. Surgical resection should be performed. Adjuvant radiotherapy or chemotherapy has no establish role in pilocytic astrocytic lesions.

Adult supratentorial extraventricular anaplastic ependymoma: Therapeutic approach and clinical review

We report a 69-year-old patient with left paresthesia and hemiparesis. Magnetic resonance imaging revealed a right frontoparietal cystic tumor. A subtotal surgical resection was performed, and an Ommaya reservoir was left in place. The pathological diagnosis was supratentorial extraventricular anaplastic ependymoma. Radiation therapy was administered, and Ommaya reservoir drainages were performed. Four months after, her clinical status deteriorated after a reservoir drainage and image revealed an acute hemorrhage. An additional resection was carried out, and chemotherapy was undergone. One month later the tumor relapsed and the patient died 18 months after initial diagnosis. Some poor prognostic factors have been suggested in the literature: Young age, incomplete tumor resection – eloquent area location, histological anaplasia, supratentorial, and extraventricular locations. Ommaya reservoirs may be used in cystic lesions as a temporary measure only. Surgery is the mainstay of therapy with adjuvant radiotherapy and/or chemotherapy.

Intratechal Chemotherapy Treatment Through an Ommaya Reservoir Catheter for Meningeal Carcinomatosis: A Single-Centre Experience

INTRODUCTION Meningeal carcinomatosis is defined as tumour cells infiltration of leptomeninges and subarachnoid space. It is normally related with poor survival (2 - 5 months). The best multidisciplinary treatment for this condition is a matter of discussion. Patients condition and the natural history of the disease should be considered in the decision making process. MATERIAL AND METHODS Retrospective cohort analysis of patients submitted to Ommaya Reservoir placement due to systemic solid tumour meningeal carcinomatosis between 2006 and 2014. RESULTS Twenty three patients were included (19 females, four males) with median age of 56.1 ± 2.2 years. The primary tumour was: breast - 16 patients, lung - four patients, stomach, bladder and cervix - one patient each. No complications were seen (infection, intracranial haematoma or CSF fistula). The median survival was 26.4 ± 7.7 weeks, range between nine days and 118 weeks (21/23 patients). Male gender was related to poor prognosis in crude analysis (p value = 0.0032). Breast adenocarcinoma was related with better prognosis in adjust analysis (p value = 0.036, HR: 4.36 ± 3.06; 95% IC: 1.10 - 17.25). Longer time between initial tumour and meningeal carcinomatosis diagnosis was related to a better outcome but without statistical significance. DISCUSSION Despite the low complication rate of Ommaya reservoir placement, the poor response to chemotherapy and the disease prognosis should be considered in patients with poor functional status. The relationship observed between the primary tumour and the overall survival supports that meningeal carcinomatosis should not be considered a disease by itself but always in the context of a systemic disease. The low incidence of breast cancer in male population might be related with it poorer prognosis. CONCLUSION Meningeal carcinomatosis has a poor prognosis. Breast adenocarcinoma, longer time between initial tumour and meningeal carcinomatosis diagnosis, and age < 60 years were related with longer survival.

Satisfação com o Internato Médico em Portugal

INTRODUCTION In the last years, the global context of medical education and Medical Residency programs in Portugal suffered substantial changes. The primary objective of this study was to evaluate and characterize medical residents ́ satisfaction with medical residency programs in Portugal and to identify features that could be improved. MATERIAL AND METHODS We utilized as model the survey Postgraduate Hospital Educational Environment Measure that has been developed in the United Kingdom and is speci cally targeted to medical residents. The survey was translated and adapted to the Portuguese reality. The survey was available online during April and May of 2016. RESULTS A total of 3456 responses were obtained, corresponding to a response rate of 35%. Endocrinology/Nutrition, Cardiology, Anesthesiology, Family Physician and Gastroenterology were the specialties in which the degree of satisfaction was higher, while Forensic Medicine, Medical Oncology, Internal Medicine, General Surgery and Pneumology showed the lowest level of satisfaction. DISCUSSION This study presented a high response rate when compared to previous studies. Portuguese medical residents presented high levels of satisfaction. Depending on year of medical residency, region, type of specialty and type of hospital marked asymmetries were noticed. CONCLUSION The survey ́s results should constitute in the future a support tool for the implementation of local and national measures relating to the medical residency. It is advisable to regularly conduct satisfaction surveys to medical residents.