Magnetic resonance imaging of parotid gland tumors: a pictorial essay.

Imaging of parotid gland tumors is challenging due to the wide variety of differential diagnoses. Malignant parotid tumors can have very similar features to benign ones, such as slow growth and displacement instead of infiltration of neighboring structures. Malignant and benign tumors may therefore not be clinically distinguishable. Correct characterization of parotid tumors (i.e., benign or malignant) determines preoperative treatment planning and is important in optimizing the individualized surgical plan. Magnetic resonance imaging (MRI) is the imaging modality of choice for evaluation of suspected parotid gland lesions and differentiation between benign and malignant lesions. Certain conventional MRI features can suggest whether a mass is more likely to be a benign or low-grade malignancy or a high-grade malignancy and adding diffusion-weighted imaging or advanced MRI techniques like perfusion can aid in this distinction. Morphological features seen on MRI, such as low signal on T2-w, infiltrative changes or ill-defined margins, change over time and diffusion restriction can point to the malignant nature of the lesion. MRI is useful for detection and localization of the lesion(s), and associated findings like perineural spread of tumor, lymph node involvement and infiltrative changes of the surrounding tissues. In this pictorial essay, we present selected images of a variety of benign and malignant parotid tumors and emphasize the MRI features that may be useful in their characterization

Tarantula Toxins Interact with Voltage Sensors within Lipid Membranes

Voltage-activated ion channels are essential for electrical signaling, yet the mechanism of voltage sensing remains under intense investigation. The voltage-sensor paddle is a crucial structural motif in voltage-activated potassium (Kv) channels that has been proposed to move at the protein–lipid interface in response to changes in membrane voltage. Here we explore whether tarantula toxins like hanatoxin and SGTx1 inhibit Kv channels by interacting with paddle motifs within the membrane. We find that these toxins can partition into membranes under physiologically relevant conditions, but that the toxin–membrane interaction is not sufficient to inhibit Kv channels. From mutagenesis studies we identify regions of the toxin involved in binding to the paddle motif, and those important for interacting with membranes. Modification of membranes with sphingomyelinase D dramatically alters the stability of the toxin–channel complex, suggesting that tarantula toxins interact with paddle motifs within the membrane and that they are sensitive detectors of lipid–channel interactions

Primary intraosseous carcinoma in the pediatric and adolescent mandible

Abstract Background Primary intraosseous carcinoma (PIOC) is a rare malignant odontogenic tumor that predominantly occurs in males older than 50 years. PIOC can be misdiagnosed as odontogenic cyst because it occasionally shows a well-defined border on radiography. In this study, related literatures of pediatric and adolescent PIOC cases were analyzed under strict PRISMA guidelines along with an adolescent case who was provisionally misdiagnosed as an odontogenic cyst. Methods All case reports for PIOC published in English from 1966 to 2021 were collected. Cases under the age of 20 were classified as pediatric and adolescent populations in this study. A total of 12 pediatric and adolescent cases including 11 PIOCs from the literature and one new case of a 14-year-old female were analyzed. Clinical and radiographic features, diagnosis and treatment approaches, and prognosis were investigated. Results Ages ranged from 4 to 18 years. The female to male ratio was 1.4:1. Seven cases occurred in the mandible. Swelling was observed in 11 patients. The radiologic borders were well-defined in six cases and corticated in four cases. Tooth displacement and root resorption were observed in four and six cases, respectively. The provisional diagnosis for seven patients was odontogenic cyst and enucleation was performed in six cases including the new case. During the follow-up period, local recurrence occurred in three patients. The pediatric and adolescent PIOC cases with local recurrence showed poor prognosis. The locally recurred lesion in the new case did not decrease in size despite concurrent chemo-radiation therapy. Conclusions Three-dimensional imaging modalities and incisional biopsy with multiple specimens are necessary to rule out PIOC in the lesions with atypical radiographic findings. PIOC should be diagnosed differentially from odontogenic cyst even in pediatric and adolescent populations to properly manage the disease with poor prognosis

The impact of pegylated interferon and ribavirin combination treatment on lipid metabolism and insulin resistance in chronic hepatitis C patients

Background/AimsLipid profile and insulin resistance (IR) are associated with hepatitis C virus (HCV) and may predict the chronic hepatitis C (CHC) treatment response. The aim of this study was to determine the association between CHC treatment response and lipid profile and IR change during treatment.MethodsIn total, 203 CHC patients were reviewed retrospectively between January 2005 and December 2011 at Soon Chun Hyang University Hospital. The lipid profile, homeostasis model for assessment (HOMA) of IR (HOMA-IR), and HOMA of β cells (HOMA-β) were evaluated before interferon plus ribavirin therapy (BTx), at the end of treatment (DTx), and 24 weeks after the end of treatment (ATx).ResultsA sustained virologic response (SVR) was achieved by 81% of all patients (49/60), 60% (n=36) of whom possessed genotype 1, with the remainder being non-genotype-1 (40%, n=24). Apart from age, which was significantly higher in the non-SVR group (SVR, 48.0±11.2 years, mean±SD; non-SVR, 56.6±9.9 years; P2.5), HOMA-IR was significantly changed at DTx in the SVR group.ConclusionsLDL-C appears to be associated with HCV treatment in SVR patients. Furthermore, eradication of HCV may improve whole-body IR and insulin hypersecretion, as well as high baseline insulin resistance (HOMA-IR >2.5)

Radiological Spectrum of Hepatic Mesenchymal Hamartoma in Children

OBJECTIVE: A hepatic mesenchymal hamartoma is an uncommon benign tumor in children and little is known about the spectrum of its radiological features. The purpose of this study is to describe the spectrum of radiological features of a hepatic mesenchymal hamartoma in children. MATERIALS AND METHODS: Thirteen children with a pathologically confirmed hepatic mesenchymal hamartoma (M:F = 7:6; mean age, 3 years 2 months) were included in our study. Ultrasonography (US) was performed in nine patients including color and power Doppler US (n = 7). CT scans were performed in all patients. We evaluated the imaging findings of the hepatic mesenchymal hamartomas and the corresponding pathological features. RESULTS: Each patient had a single tumor (mean diameter: 13 cm [1.8-20 cm]). On CT and/or US, four patients (31%) had a "multiseptated cystic tumor", five patients (38%) had a "mixed solid and cystic tumor", and four patients (31%) had a "solid tumor." The septa of the cystic portion were thin in the multiseptated cystic tumors and irregularly thick in the mixed solid and cystic tumors as seen on US. On a post-contrast CT scan, solid portions or thick septa of the tumors showed heterogeneous enhancement. The amount of hepatocytes was significantly different among the three tumor groups according to the imaging spectrum (p = 0.042). CONCLUSION: A hepatic mesenchymal hamartoma in children can show a wide spectrum of radiological features, from a multiseptated cystic tumor to a mixed solid and cystic tumor, and even a solid tumor

Polypoid Endobronchial Lung Cyst with Bronchoscopic Removal : A Case Report

Pulmonary bronchogenic cyst in adults is rare and the typical appearance is a sharply circumscribed, round or oval nodule or mass, usually in the medial third of the lungs. Bronchial polyps are rare histopathologically distinct nonneoplastic endobronchial lesions and are classified as multiple papillomas, solitary papillomas, and inflammatory polyps. We herein report a patient with polypoid endobronchial lung cyst. A 68-yr-old woman presented with a discomfort and pain in the right upper chest of four weeks??duration. Chest radiography revealed a cystic lesion in the right upper lung. Computed tomography revealed a 4×5 cm sized large cyst. Neither enlarged mediastinal lymph nodes nor extrabronchial involvements were observed. Flexible bronchoscopy revealed a peduncular polyp about 2 cm in length originating from the anterior segment of right upper lung. After bronchoscopic removal of polyp, cystic lesion of the right upper lung disappeared

A Case of Multidrug-Resistant Salmonella enterica Serovar Typhi Treated with a Bench to Bedside Approach

We report a relapsed case of a 25 year-old man with multi-drug resistant Salmonella serovar Typhi (MDRST) bacteremia who had recently returned from travel in India. Due to unresponsiveness to ciprofloxacin and ceftriaxone, we examined the strain's resistance to quinolones and extended-spectrum β-lactamases (ESBLs). The strain had a single gyrA mutation at codon 83 (Ser83Phe), which explains its decreased susceptibility to fluoroquinolone and resistance to nalidixic acid. In the screening tests of ESBLs, TEM-1 was positive, which is beta-lactamase but not ESBL. The patient was finally successfully treated with meropenem and aztreonam. In the presence of clinical unresponsiveness despite favorable sensitivity tests, further laboratory evaluations are needed, which should include studies of genes related to antibiotic resistance and ESBLs. In addition, further prospective trials should be done about the possible inclusion of antibiotics not yet mentioned in the current guidelines. With MDRST on the rise worldwide, the most optimal and effective line of antibiotic defense needs to be devised