Neuroimaging Curriculum for Neurology Trainees: Report from the Neuroimaging Section of the AAN

Neuroimaging plays a major role in the evaluation of patients with neurological disorders. Surveys of neurologists have revealed that most rely on their own readings of images for patient management, and a majority believe that neurologists should be allowed to officially interpret and bill for scan reviews. The importance of neuroimaging training for neurology residents has been stressed by the Association of University Professors of Neurology. Although there is a desire to promote the neuroimaging education of neurologists, no curricula have existed previously. The Neuroimaging Section of the American Academy of Neurology (AAN) developed a task force of practicing neuroimagers to provide a neuroimaging curriculum for neurological trainees and training directors. The resulting curriculum is available on the Web sites of the AAN (http://www.aan.com) and the American Society of Neuroimaging (http://www.asnweb.org/education/curriculum.shtml) and will be updated as the need arises through evolving technology or breadth of applications. This curriculum should help in the design of neurology residency and fellowship programs and subspecialty pathways in which adequate neuroimaging education and training are desired for various reasons, including certification and the demonstration of competency and proficiency.     

Characterization of endothelin-converting enzyme activities in ARPE-19 cells, a human retinal pigmented epithelial cell line.

Elevated endothelin-1 (ET-1) levels are detected in patients with glaucoma. ET-1 is produced from its precursor, Big ET-1, by endothelin-converting enzyme (ECE). Characterization of ET- 1 secretion and ECE activity was performed in ARPE-19 cells, a human retinal pigmented epithelial cell-line. The ET(B) receptor but not the ET(A) receptor was detected by immunoblotting and cross-linking using 125I-ET-1 at the plasma membrane (PM). Tumor necrosis factor-alpha (10 nmol/L) induced a 700% increase in ET-1 levels and such an effect was further potentiated by BQ788, an ET(B) receptor antagonist, suggesting the involvement of ET(B) receptor in ET-1 clearance. Big ET-1-converting activities were detected in both the PM and cytosol. Phosphoramidon, thiorphan, acidification, and phenanthroline inhibited PM ECE activity; the cytosolic ECE activity was not affected by phenanthroline but was inhibited by the others. In contrast, ECE cytosolic activities were activated by acidification (pH 6.4), suggesting the involvement of ECE-2 or cathepsin-like activity. Pepstatin, a potent inhibitor of cathepsins, and phosphoramidon, a potent inhibitor of ECE, inhibited the cytosolic conversion of Big ET-1 peptide by 46% and 35%, respectively, whereas the combination of both inhibited the cytosolic activity by 93%. Based on immunoblotting, ECE-1 was detected only at the PM, whereas ECE-2 and cathpesins B and D were detected in the cytosol. In summary, ET-1 production in RPE is regulated by at least two isoforms of ECE, (cytosolic and PM) as well as cathepsins.     

T2 hypointensity in the deep gray matter of patients with multiple sclerosis: a quantitative magnetic resonance imaging study.

CONTEXT: While gray matter T2 hypointensity in multiple sclerosis (MS) has been associated with physical disability and clinical course, previous studies have relied on visual magnetic resonance imaging (MRI) assessments. OBJECTIVE: To quantitatively determine if T2 hypointensity is associated with conventional MRI and clinical findings in MS. DESIGN: Case-control study. SETTING: University-affiliated community-based hospital. SUBJECTS: Sixty patients with MS and 50 controls. MAIN OUTCOME MEASURES: T2 intensities of the substantia nigra, red nucleus, thalamus, putamen, globus pallidus, and caudate; third ventricular width; total brain T1 (hypointense) and T2 (hyperintense) lesion volumes; Expanded Disability Status Scale (physical disability) score; and disease course. RESULTS: Deep gray matter T2 hypointensity was present in patients with MS in all structures (P<.005) except for the substantia nigra. T2 hypointensity was associated with third ventricle enlargement and higher T2 but not T1 plaque load. The regression model predicting third ventricle width included caudate T2 hypointensity (P =.006). The model predicting T2 lesion load included globus pallidus T2 hypointensity (P =.001). Caudate T2 hypointensity was the only variable associated with disability score in regression modeling (P =.03). All T2 hypointensities differentiated the secondary progressive from the relapsing-remitting clinical courses. The final model (P<.001) predicting clinical course retained T2 hypointensity of the thalamus, caudate, and putamen but not MRI plaques or atrophy. CONCLUSIONS: Gray matter T2 hypointensity in MS is associated with brain atrophy and is a stronger predictor of disability and clinical course than are conventional MRI findings. While longitudinal studies are warranted, these results suggest that pathologic iron deposition is a surrogate marker of the destructive disease process.     

Primary cardiac sarcoma

Primary malignant lesions of the heart are rare. Although myxomas have been extensively described, there is a paucity of large studies on non-myxomatous cardiac tumours. On the other hand, there are several case reports on specific histopathological variants, in small numbers. Consequently there exists no consensus on therapeutic modalities for cardiac sarcomas. The prognosis for these lesions remains dismal, despite the enhanced diagnostic ability of newer technology. The reasons for the dismal prognosis are (1) the advanced tumour stage at presentation, (2) non-specific symptomatolgy, (3) insufficient awareness of these lesions, due to their rarity, (4) delayed diagnosis and/or misdiagnosis, which leads to (5) advanced tumour stage at presentation. Thus a vicious cycle is created. This article addresses these issues, deals with the surgically relevant modes of presentation, rather than the histopathology, and reviews the diagnosis and management options for the various sarcomas, categorized by the site and extent of cardiac involvement. Clinicians should be familiar with the presentation of these tumours and have a high index of suspicion, since the potential for long-term survival following resection does exist. Wide surgical resection remains the cornerstone of sarcoma therapy. Complete characterization of tumour extent using echocardiography and CT/MRI is mandatory to achieve this goal. Radical resections such as ‘bench surgery’ and transplantation may reduce local recurrence, but the risk of metastatic disease remains. The clinical experience with such approaches is limited. The role of adjuvant therapy is not yet established. In no other field of cardiac surgery would a multidisciplinary approach be more useful, in achieving cure or long-term palliation.     

Evaluation of the mutagenic potential of corn (Zea mays L.) grown in untreated and atrazine (AAtrex) treated soil in the field

Bacterial assays using extracts from field corn plants (harvested at one month, silage and mature stages) do not indicate that soil treatment with atrazine, at its maximum use rate, alters the endogenous mutagens present in these extracts, nor that atrazine itself is degraded to mutagenic products. Extracts of corn grown in soil treated with AAtrex were equally mutagenic with those of corn grown in untreated soil when tested in Salmonella typhimurium TA-100 by a reversion assay or in Salmonella typhimurium TM-677 in a forward mutation assay. Higher concentrations of histidine in corn grown in AAtrex treated soil may interfere with the reversion assay, but do not affect the forward mutation assay. The nature of the agent(s) responsible for the positive response was not determined. The mutagenicity may be due to natural plant constituents, an artifact of the sample preparation, or mycotoxins from some unrecognized plant infection. The experimental results in these field studies do not show that atrazine is degraded or metabolized by corn plants to mutagens in this sensitive bacterial assay.     

Synchronous gastric stromal tumor and cecal adenocarcinoma.

Gastrointestinal stromal tumors are rare intestinal tumors. There have been reports of this tumor occurring with other conditions and tumors. We report a 55-year-old man who presented with a gastric stromal tumor and cecal adenocarcinoma, necessitating right hemicolectomy and partial gastrectomy at the same sitting.     

Unusual presentation of laryngeal foreign bodies — report of two rare cases

Aspiration of a foreign body into the respiratory tract is a common and serious problem in childhood but is rare in adults. Two interesting cases in which the diagnosis of foreign body in the larynx was not suspected preoperatively are being reported. A three and half year old female child was diagnosed as a case of bronchitis and was later found to have a metallic spring in the supraglottic region which was removed by direct laryngoscopy under general anesthesia. The other patient, a 32-year-old male, was diagnosed to have a fibrous lesion in the larynx one year previously, and on laryngoscopy a vegetable, spiculated foreign body was found after excising the fibrous lesion on the left false cord. Both the cases are symptom free 18 months after endoscopy.