Intracanalicular arachnoid cyst mimicking acoustic neuroma: CT and MRI.

A patient with a surgically proven intracanalicular arachnoid cyst was studied using computed tomography, magnetic resonance imaging, and air CT cisternography. The lesion had a similar radiographic appearance to acoustic neuroma and therefore, although rare, must be considered in the differential diagnosis of intracanalicular mass lesions. We report a case in which examination was performed, in evaluating the lesion, utilizing high-resolution air CT cisternography and magnetic resonance imaging (MRI).     

Suramin inhibits bone resorption and reduces osteoblast number in a neonatal mouse calvarial bone resorption assay.

The antineoplastic properties of suramin, a polyanionic agent with demonstrated antigrowth factor activity, are under evaluation in vitro, in vivo, and in clinical trials. Suramin has been shown to have antitumor activity in patients with advanced, hormone refractory prostate cancer. During these trials, significant resolution of osseous pain was observed in nearly three quarters of the patients treated with suramin. To evaluate the effect of suramin on bone cells, we studied the effect of suramin on bone resorption in a neonatal mouse calvarial assay. Suramin inhibited bone-resorbing activity in a dose-related fashion and had an additive effect with calcitonin. Calvaria pretreated with suramin had less bone-resorbing activity, fewer attached osteoblasts, and less medium alkaline phosphatase activity than control calvaria. Suramin also inhibited osteoclastic release of tritiated proline from labeled bone in a dose-dependent fashion. The effect of metastatic prostate carcinoma on bone is incompletely understood, but may be moderated by tumor-produced factors and/or cytokines. The effects of several such agents, therefore, were examined in combination with suramin. Bone resorption induced by PTH, epidermal growth factor, tumor necrosis factor, and a tumor-produced factor, PTH related-protein, was blocked by suramin. The ability of suramin to inhibit the bone-resorbing effects of several cytokines suggests that its mechanism may involve direct action on bone metabolism. Autoradiography performed on calvaria treated with labeled suramin demonstrated heavy deposition of suramin on the outer surface of the matrix, adjacent to osteoblasts and osteoclasts lining the outer table, suggesting that bone cells may be subject to high local concentrations of the drug, in keeping with this hypothesis.     

The Risk of Sulfasalazine- and Mesalazine-Associated Blood Disorders

Sulfasalazine (SASP) has often been reported to cause serious blood disorders, particularly agranulocytosis; however, little quantitative information is available to estimate the risk or to identify possible modifiers of the risk. We used comprehensive clinical information recorded on office computers by selected general practitioners in Britain to conduct a follow-up study of some 10,000 users of SASP and some 4000 users of mesalazine to estimate the risk of blood disorders associated with these drugs. Overall, the frequency of blood disorders attributable to SASP was 27/10,332 (2.6/1000 users). The risk for SASP users who were treated for arthritic disorders (6.1/1000 users) was some 10 times higher than that for users who were treated for inflammatory bowel disease (0.6/1000 users). There were no cases of blood disorders in users of mesalazine.     

Early complications of tracheotomy. Incidence and management

Tracheotomy is associated with multiple and potentially life-threatening complications even under elective conditions. Minor bleeding, tube displacement or obstruction, subcutaneous emphysema, and pneumothorax are the most commonly encountered complications. Attention to details and the availability of adequate instrumentation, lighting, and trained personnel are essential to minimize morbidity.     

An approach to fractures of the midface: An interactive tutorial

Purpose: To describe an educational computer aided instruction program dealing with diagnosis and classification of facial fractures. Methods: A program was created for use on Macintosh computers using a graphic presentation package. This program allows for the display of high resolution digitized radiographic images and illustrations, along with integrated voice and text information. Users can interact with the program to review complex concepts or study additional cases. Case material was obtained from selected high quality plain radiographs and computed tomography (CT) scans obtained in the trauma center of one institution, and was scanned on a high resolution digital scanner with image parameters optimized for viewing on the Macintosh high resolution color monitor. Results: The program has been installed in the computer aided instructional laboratories or trauma centers at The University of Texas Health Science Center, Houston; The University of Alabama, Birmingham; Emory University School of Medicine, Atlanta, Georgia; and The University of North Carolina, Chapel Hill. The program is available to radiology residents and medical students rotating on the trauma radiology services at these institutions. Completion of the program requires 30–45 minutes. Conclusion: Based on our initial experience, the program has been used by residents in the training programs of all institutions with favorable results.     

Perceived risk as a factor influencing attitudes toward physically disabled children

The effects of perceptions of risk on attitudes toward handicapped children were studied. Five hundred twenty two nonhandicapped children between the ages of 8 and 19 were assigned to one of four experimental conditions in a basic 2×2 (Risk×Interview) paradigm. Some subjects were assigned to a high risk condition whereby if they indicated they would like to be friends with a handicapped peer, they were told that they might actually have to befriend a handicapped youngster who was about to enter their class; other subjects were not told about any personal involvement with the handicapped child. In the Interview factor, about half the subjects were informed that their attitudes would be known to other group members, the other half of subjects were told their attitudes would remain private. The 2×2 paradigm was studied with children at three ages levels: 8–11; 12–15; 16–19. Results revealed three significant main effects, generally supporting the hypothesis regarding the effects of risk factors.     

GM1 ganglioside partially rescues cultured dopaminergic neurons from MPP-induced damage: dependence on initial damage and time of treatment

GM1 ganglioside is believed to be important in promoting the recovery of neurons from injury. The present study assesses the ability of GM1 to repair or prevent the damage of dopamine neurons caused by the neurotoxin 1-methyl-4-phenylpyridinium (MPP⁺). Treatment of mesencephalic cell cultures with 2.5 μM MPP⁺ resulted in the loss of 30% of tyrosine hydoxylase (TH) immunoreactive neurons. In contrast, cultures administered 100 μM GM1 ganglioside for 3 days after toxin treatment contained nearly control numbers of TH⁺ neurons (97%). This reparative effect of GM1 was reflected in parallel increases in TH enzyme activity, dopamine and dopac levels. Cultures sustaining greater insult from higher doses of MPP⁺ (5.0–10.0 μM) did not benefit from ganglioside treatment, suggesting that rescue by GM1 depended on the degree of initial damage to cells. Moreover, the timing of ganglioside treatment was critical; pretreatment with GM1 alone did not prevent or attenuate the damage caused by subsequent incubation in 2.5 μM MPP⁺.