A short history of mediastinal tumours.

The mediastinum constitutes an area of special surgical interest due to important anatomical relationships and histopathologic variability of mediastinal primary and metastatic tumours. Mediastinum was considered inaccessible until the end of the 19th century. For many decades the diagnosis of mediastinal disease relied solely upon clinical presentation, and the mainstay of treatment was medical therapy. The advancements in radiology and intraoperative ventilatory support facilitated the improvement of certain diagnostic and therapeutic approaches to mediastinal disease.

Geometry-informed irreversible perturbations for accelerated convergence of Langevin dynamics.

We introduce a novel geometry-informed irreversible perturbation that accelerates convergence of the Langevin algorithm for Bayesian computation. It is well documented that there exist perturbations to the Langevin dynamics that preserve its invariant measure while accelerating its convergence. Irreversible perturbations and reversible perturbations (such as Riemannian manifold Langevin dynamics (RMLD)) have separately been shown to improve the performance of Langevin samplers. We consider these two perturbations simultaneously by presenting a novel form of irreversible perturbation for RMLD that is informed by the underlying geometry. Through numerical examples, we show that this new irreversible perturbation can improve estimation performance over irreversible perturbations that do not take the geometry into account. Moreover we demonstrate that irreversible perturbations generally can be implemented in conjunction with the stochastic gradient version of the Langevin algorithm. Lastly, while continuous-time irreversible perturbations cannot impair the performance of a Langevin estimator, the situation can sometimes be more complicated when discretization is considered. To this end, we describe a discrete-time example in which irreversibility increases both the bias and variance of the resulting estimator.

Infrared Spectroscopic Study and Mathematical Simulations of Carotid Atherosclerosis.

BACKGROUND/AIM: The pathogenesis, treatment and prevention of atherosclerosis continue to be the subject of intensive research and study by the scientific community. Based on Fourier-transform infrared spectra and 3D-Doppler echogram, we attempted to develop a computational simulation model for predicting the association of atherosclerotic risk factors with pathogenic molecular structural changes. MATERIALS AND METHODS: Atheromatic carotid arteries from 56 patients (60-85 years old) were used as samples. Color 3D-Doppler echogram screening was performed on all patients preoperatively. Each infrared spectrum consisted of 120 co-added spectra at a spectral resolution of 4 cm-1 Results: The infrared spectral analysis reveals 'marker bands', such as the 1,744 cm-1 band assigned to aldehyde formation and to the 'fingerprint' digital spectral region of 1,050-1,169 cm-1, characteristic of the presence of advanced glycation end products (C-O-C). The accumulation of calcium phosphate salts increases the formation rate of stenosis. The critical point of stenosis risk starts at about 45%, while when stenosis is over 60-70%, the risk of ischemic stroke or other major adverse cardiovascular events increases dramatically. CONCLUSION: Fourier-transform infrared spectroscopy and mathematical simulation models showed that carotid artery stenosis over 45% reduces the blood flow rate, while stenosis over 65% dramatically increases the hemodynamic disturbance, with a parallel increase the rate of ischemic stroke or other major adverse cardiovascular events.

Periocular Facial Scald Burns in Children: Is Ophthalmology Consultation Necessary?

OBJECTIVES: Criteria that predict the need for ocular injury treatment in children who suffer periocular facial scald burns are not known. The purpose of this study was to evaluate the incidence and management of ocular injuries among children sustaining facial scald burns and to determine predictors of injuries requiring additional treatment. METHODS: Children treated at a burn center with periocular facial scald burns were analyzed. Patient and injury profiles were compared between those evaluated and not evaluated by an ophthalmologist. Factors associated with an ocular injury requiring treatment were determined, and treatment differences before and after ophthalmology consultation were evaluated. RESULTS: Seventy-three children with facial scald burns were identified, none with a full-thickness injury. Thirteen children had ocular findings on examination including corneal abrasion, conjunctivitis, scleral burn, and chemosis of the conjunctiva. Twenty-three patients received erythromycin ointment, only 8 of whom had a documented ocular injury. Children seen by an ophthalmologist (n = 24) more often had a positive finding on examination (37.5% vs 8.2%, P = 0.007) and received treatment (66.7% vs 14.3%, P < 0.001). Only 4 patients had modification in their treatment plan after consultation, 3 of whom were started on treatment despite not having a positive finding on examination. CONCLUSIONS: Ocular injury after periocular facial scald burns is an infrequent finding. Among children with partial-thickness periocular facial scald burns, initial evaluation and treatment without ophthalmology consultation are appropriate. Ophthalmic antibiotic ointment is an appropriate initial treatment in most symptomatic patients, with ophthalmologic consultation being limited to children without symptomatic improvement.

Epidemiological trends in the diagnosis of melanoma in a Southern European population: analysis of a large database from a tertiary referral center.

The aim of this study was to present the epidemiological, clinicopathological, and treatment characteristics of patients diagnosed and treated in a tertiary referral center and to analyze independent factors associated with these characteristics. In this cohort study, epidemiological, clinicopathological, and treatment characteristics of 1461 consecutive melanoma patients diagnosed and treated in a tertiary referral center in 1987-2015 were prospectively collected in a registry. All patients underwent resection of their melanoma lesion. Multiple logistic regression analysis was used to examine independent correlations between characteristics. Internal validation of these correlations was performed by the bootstrap method. The median age of the patients was 53 years. Female sex had a slight predominance, whereas the majority were of Southern European origin. Superficial spreading melanoma was associated with younger age (P<0.001), whereas the nodular melanoma histological subtype was associated independently with indoor occupation (P=0.021) and diagnosis in the years 2004-2015 (P=0.002). Melanomas with Breslow thickness above 1.0 mm were associated with skin type III-IV (P=0.021) and diagnosis in the years 1987-2003 (P=0.046). In addition, histological ulceration was associated with older age (P=0.004) and diagnosis in the years 1987-2003 (P<0.001), whereas histological regression was associated independently with older age (P=0.001). This study presented independent associations between epidemiological, histopathological, and treatment characteristics, which might help to better understand melanoma disease and treatment practices in Southern Europe.

Pseudoexfoliation syndrome without glaucoma: White matter abnormalities detected by conventional MRI and diffusion tensor imaging.

PURPOSE: To assess macro- and microstructural brain changes in patients with pseudoexfoliation syndrome (PXS). MATERIALS AND METHODS: Comprehensive ophthalmic examination and brain MRI were conducted on 20 patients with PXS without glaucoma (aged 62.75 ±â€¯0.4 years) and 20 controls (aged 62 ±â€¯0.6 years). White matter (WM) integrity was evaluated on FLAIR and single-shot multisection SE-EPI diffusion tensor imaging (DTI) sequences. The presence and the number of white matter hyperintensities (WMHIs) on FLAIR images was compared between all patients and control subjects. Microstructural WM changes on DTI was evaluated using Tract-based spatial statistics (TBSS). DTI metrics of the optic tracts were assessed by the region-of-interest (ROI) method. RESULTS: A significantly higher number of WMHIs was found in the patients with PXS than in the control subjects (P ≤ 0.002). On DTI the patients showed bilateral increase in the mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) values in the anterior thalamic radiation, the inferior fronto-occipital fasciculus, the superior longitudinal fasciculus, the inferior longitudinal fasciculus and the forceps minor. TBSS revealed no significant difference in fractional anisotropy (FA) values, but ROIs analysis of the optic tracts revealed decreased FA values in the patients. CONCLUSION: MRI in patients with PXS detects abnormalities in the brain and the optic tracts at a subclinical stage. Early detection of microstructural changes could be useful to guide appropriate treatment to impede the disease process.

Immunohistochemical Study of Vasculogenic Mimicry and Angiogenesis in Melanocytic Tumors of the Eye and the Periocular Area.

BACKGROUND/AIM: The ability of a tumor to grow requires a sufficient blood supply. Microvascular density is considered the standard for assessing the neovasculature. Tumor cell vasculogenic mimicry refers to the formation of tumor cell-lined vessels that contribute to tumor neovascularization. The aim of the present work was to study angiogenesis and vasculogenic mimicry in benign and malignant melanocytic tumors of the eye and the periocular region. PATIENTS AND METHODS: Histological sections from 118 patients were studied. Eighty-eight of the patients had nevi while the remaining 30 had malignant melanomas. Microvascular density was assessed by using antibodies against the endothelial cell markers CD31 and CD34. Vascular-like channels between neoplastic cells, that were not lined by endothelial cells and thus were negative for CD31 and CD34, represented areas of vasculogenic mimicry. RESULTS: Angiogenesis was more pronounced in melanomas compared to melanocytic nevi and was increased in melanomas with high mitotic index and/or epithelioid cell preponderance compared to melanomas with low mitotic index and/or spindle cell predominance. Vasculogenic mimicry was observed in many melanomas, while it was evident in the minority of benign nevi as well. CONCLUSION: The existence of vasculogenic mimicry in benign nevi might have prognostic implications.

Vasculogenic mimicry: lessons from melanocytic tumors.

Tumor cell vasculogenic mimicry refers to the formation of tumor cell-lined vessels that contribute to tumor neovascularization and nutrient and oxygen supply. These tumor cells express many endothelial and stem cell markers, resulting in them having a unique phenotype. This phenomenon is observed in a variety of neoplasms, such as glioblastomas and sarcomas, as well as breast, ovarian, liver and lung carcinomas. It is also evident in melanocytic lesions, regardless of their benign or malignant nature. The biochemical and molecular events that regulate vasculogenic mimicry provide opportunities for development of novel forms of tumor-targeted treatments. Furthermore, the presence of this process in a tumor might have prognostic implications.

Encoding of rules by neurons in the human dorsolateral prefrontal cortex.

We use rules to extend learned behavior beyond specific instances to general scenarios. The prefrontal cortex (PFC) is thought to play an important role in representing rules, as evidenced by subjects who have difficulty in following rules after PFC damage and by animal studies demonstrating rule sensitivity of individual PFC neurons. How rules are instantiated at the single-neuronal level in the human brain, however, remains unclear. Here, we recorded from individual neurons in the human dorsolateral prefrontal cortex (DLPFC) as subjects performed a task in which they evaluated pairs of images using either of 2 abstract rules. We find that DLPFC neurons selectively encoded these rules while carrying little information about the subjects' responses or the sensory cues used to guide their decisions.

Role of resection of malignant peripheral nerve sheath tumors in patients with neurofibromatosis type 1.

OBJECT: Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas that often arise from major peripheral nerves. Approximately half of MPNSTs arise in patients with neurofibromatosis Type 1 (NF1) who, in comparison with patients without NF1, present at younger ages and with larger tumors that are commonly associated with extensive plexiform neurofibromas. These tumors therefore pose a particularly difficult treatment challenge because of the morbidity often associated with attempted gross-total resection (GTR). Here, the authors aim to examine what role the extent of resection and other covariates play in the long-term survival of patients with NF1 in the setting of MPNST. METHODS: The authors retrospectively reviewed the records of 23 adult patients with NF1 who underwent surgery for MPNSTs at their institution between 1991 and 2008. The primary end points of the study were mortality, local recurrence, and metastasis. Kaplan-Meier survival curves were evaluated for all patients. Differences for each of the primary end points were evaluated based on cause-specific covariates, which included tiered tumor size, tumor location, grade, resection margin status, postoperative weakness, and use of chemotherapy and radiation therapy. Multivariate analysis was performed using Cox proportional hazards models. RESULTS: Gross-total resection (p = 0.01) and surgical margin status (p = 0.034) had a statistically important role in prolonging overall survival in patients with NF1 by univariate analysis. When tumor size, location, grade, postoperative weakness, and radiation therapy were also taken into account using multivariate analysis, GTR continued to be a significant prognostic factor (p = 0.035). CONCLUSIONS: These findings suggest that GTR offers significant long-term benefit on survival in patients with NF1. Benefit on survival occurred independently of all other covariates, suggesting that complete resection should be the principal goal of treatment in this patient population.

Preoperative direct percutaneous embolization of spinal metastasis from renal cell carcinoma.

Preoperative direct percutaneous embolization has been very rarely used in hypervascular metastatic spinal tumors to decrease blood loss during the surgery. A patient is presented with solitary spinal metastasis due to renal cell carcinoma who underwent a two-stage spondylectomy. Transarterial tumor embolization with polyvinyl alcohol (PVA) particles and liquid coil placement, and percutaneous tumor embolization with PVA particles were used before the first and the second stage, respectively.

Brachial plexus reconstruction following resection of a malignant peripheral nerve sheath tumor: case report.

BACKGROUND AND IMPORTANCE: The main therapeutic approach for malignant peripheral nerve sheath tumors (MPNSTs) of the brachial plexus is wide local excision. Sacrifice of some--occasionally all--elements of the brachial plexus often is required to obtain complete resection, and therefore can be associated with significant morbidity. While peripheral nerve repair is commonly used in the setting of traumatic nerve injury, little is known about its potential use in the treatment of MPNST. CLINICAL PRESENTATION: We present a patient with an enlarging right neck mass who was diagnosed with MPNST of the brachial plexus. The patient underwent gross total resection of the tumor, requiring sectioning of the upper trunk of the brachial plexus, as well as associated divisions. Following resection, sural nerve grafts were used to connect the C5 nerve root to the anterior division of the upper trunk and the spinal accessory nerve to the suprascapular nerve, whereas a triceps branch of the radial nerve was coapted directly to the anterior division of the axillary nerve. CONCLUSION: By 20 months after surgery, the patient had regained significant strength in her upper trunk distribution and demonstrated no evidence of tumor recurrence. Brachial plexus reconstruction offers a potentially valuable surgical adjunct to MPNST treatment.

Concomitant presentation of a glioblastoma multiforme with superimposed abscess.

BACKGROUND: The coexistence of a primary brain tumor such as high-grade glioma and superimposed abscess is a rare entity and can present a diagnostic and therapeutic challenge. The concomitant abscess may not be recognized until surgery, and the overall course of treatment may require adjustment in the presence of a coinciding infection. In the present report we evaluate the diagnosis and treatment of a glioblastoma multiforme with an intratumoral abscess. METHODS: A patient was diagnosed with a glioblastoma multiforme with a concomitantly superimposed multimicrobial abscess containing coagulase-negative Staphylococcus, Acinetobacter iwofii, and Propionibacterium species. The suspected infectious source was a dental abscess with presumed secondary seeding. The patient underwent a left anterior temporal lobectomy with debulking of the lesion. Although the adjuvant therapy schedule was adjusted to accommodate the course of antibiotics, the existence of a concurrent abscess did not preclude adjuvant radiation and chemotherapy. RESULTS: The patient responded well to antibiotic treatment with no evidence of recurrent infection. He underwent a second operation for additional debulking of the lesion approximately half a year after his initial surgery. The patient died 2 years after the initial diagnosis. CONCLUSIONS: There are insufficient guidelines on the treatment of a primary brain tumor with intratumoral abscess. In this report we present our therapeutic decisions in this rare case.

Femoral branch to obturator nerve transfer for restoration of thigh adduction following iatrogenic injury.

Obturator nerve injury is a rare complication of pelvic surgery. A variety of management strategies have been reported, with conservative measures being the preferred treatment in most cases. While nerve transfer has become more commonly used for restoring brachial plexus injuries, it has rarely been applied to the lower extremities. To the authors' knowledge, this is the first report of an obturator nerve neurotization. A patient presented 7 months after an iatrogenic right obturator nerve palsy due to pelvic surgery for gynecological malignancy. She underwent a femoral branch to obturator nerve transfer to restore right thigh adduction. Ten months after the neurotization procedure, there was electromyographic evidence of almost complete obturator nerve reinnervation. At 1 year postoperatively, the patient had regained full muscle strength on thigh adduction and a normal gait. Nerve transfer could therefore be a good option in patients with obturator nerve injury whose symptoms fail to respond to conservative medical therapy.

Expression of GluR6 kainate receptor subunit in granular layer of weaver mouse cerebellum.

The Girk2 ( wv ) (weaver) mutation impairs migration of cerebellar granule cells from external to internal granular layer and induces neuronal death during the first 2 weeks of postnatal life. Kainate receptors are heteromeric ionotropic receptors of glutamate consisting of five subunits termed GluR5, GluR6, GluR7, KA1 and KA2. In order to investigate whether the weaver gene affects the expression of kainate receptors in weaver cerebellum, we determined mRNA expression levels of GluR6 kainate receptor subunit and [(3)H]kainic acid specific binding in the developing cerebellum, using in situ hybridization and receptor film autoradiography, respectively. In the weaver postnatal day 10 (P10) cerebellum, our data indicated lower levels of GluR6 mRNA expression and lower [(3)H]kainic acid specific binding in external granular layer (EGL) compared to normal EGL. Our results are indicative of either down-regulation of kainate receptors or modulation of their functional characteristics in weaver granule cells.