The short QT syndrome as a paradigm to understand the role of potassium channels in ventricular fibrillation.

The recently discovered hereditary channelopathy, the Short QT Syndrome (SQTS), is an important advance in clinical and molecular cardiology that has opened new doors for investigating the manner in which alterations in excitability and action potential morphology may facilitate the occurrence of ventricular fibrillation. In this brief review we address the molecular and genetic features of SQTS in which specific mutations in one of three different potassium channels involved in cardiac repolarization substantially increase the risk of life-threatening tachyarrhythmias. We then summarize new knowledge on the mechanism of wavebreak, which is the hallmark of reentry initiation, and on the role of potassium channels in the ionic mechanisms underlying cardiac excitation and its frequency dependence. The article argues for a detailed understanding of the ionic mechanisms that promote wavebreaks and stable rotors as an essential tool for successful anti-arrhythmic therapy in SQTS and other diseases leading to sudden cardiac death.

Paraganglioma of the temporal bone: role of magnetic resonance imaging versus computed tomography.

Paragangliomas, also known as glomus tumors or chemodectomas, are tumors arising from chemoreceptor tissue (paraganglia), which are neural crest in origin and found in higher concentration along the glossopharyngeal and vagal cranial nerve. Three types of paragangliomas are related with the temporal bone: glomus tympanicum, glomus jugulare, and glomus vagale. The role of computed tomography (CT) and magnetic resonance imaging (MRI) in diagnosing these types of tumors is discussed, along with the importance of arteriography in aiding the diagnosis and treatment. This article discusses the choice between CT and MR based on clinical symptoms and tumor location, and illustrates the newest CT, MR, and angiography applications. A brief discussion on treatment options is given.

The persistent stapedial artery.

The persistent stapedial artery is a rare congenital vascular anomaly that may present as a pulsatile middle ear mass or that may appear as an incidental finding. Five cases of persistent stapedial artery are presented. The CT findings include the absence of the ipsilateral foramen spinosum and a soft-tissue prominence in the region of the tympanic segment of the facial nerve. Three cases were associated with an aberrant internal carotid artery. Imaging identification of this variant may obviate unnecessary surgery and may help in planning surgical or endovascular interventions.

Langerhans' cell histiocytosis and juvenile xanthogranuloma of the orbit. Clinicopathologic, CT, and MR imaging features.

The clinical, radiologic, and histopathologic features of two main disorders of the orbit are discussed. Group I, Langerhans cell histiocytosis (histiocytosis X, Class I), is caused by proliferation of X histiocytic Langerhans' cells. Group II is juvenile xanthogranuloma, and Class II is related to the proliferation of non-X histiocytic (monocyte-macrophage) cells. The two diseases are of unknown cause and differ in their clinical, radiologic, and histopathologic features.

Against all odds! You still can upgrade and reimplement an MRP II (material requirements planning) system.

This article illustrates the three key elements necessary when reimplementing a closed-loop manufacturing system. The first is to accept the paradigm of people's fear of being changed. The second is to devise a methodological process to define the overall tasks, identify roles, and determine an organized approach. The third is to involve and receive commitment of all players to ensure that predefined tasks are completed on schedule.

Acute Scrotal Injuries in Athletes: Evaluation by Diagnostic Imaging.

In brief: Boxers, baseball players, and some other athletes are sometimes at risk of injury to the genitalia. For some injuries, such as testicular rupture or acute torsion, early surgery increases the likelihood of preserving function. Other injuries are more appropriately treated conservatively. When a patient has severe pain, physical examination of the scrotum can be difficult, and information obtained with ultrasound and radionuclide scintigraphy can help in the diagnosis and treatment. The authors compare normal findings with those indicating the presence of hematocele, intratesticular hemorrhage, testicular fracture, torsion, and epididymo-orchitis.

Duodenal neoplasms: role of CT.

In a retrospective study of 14 cases of duodenal neoplasms evaluated by computed tomography (CT), there were four primary adenocarcinomas of the duodenum, one lymphoma, five metastatic carcinomas, two duodenal lipomas, one villous adenoma, and one leiomyoma. The CT findings were diagnostic in patients with duodenal lipomas. In 11 cases, a primary origin of the mass was clearly identifiable in the duodenum. Thickening of the bowel wall, tumor necrosis, ulceration, and intraluminal defects were common. The relationship of the masses to adjacent structures was clearly shown on CT scans. Extraluminal extent of the lesion was noted on CT scans in seven patients; however, at surgery only four of six were found to have extramural disease. The presence of adenopathy, liver metastases, and vascular and mesenteric invasion were also demonstrated on CT scans. Twelve patients underwent upper gastrointestinal tract series. A duodenal abnormality was seen in all 12 patients, but the extramural extent and distant metastatic involvement could not be seen on these examinations. CT scans allowed the accurate staging of eight of ten malignant lesions and thus helped in the management of duodenal tumors.

[Examination of the enzymatic functions of the normal liver in black Africans (Apropos of 50 Senegalese cases)]. / Contribution à l'exploration des fonctions enzymatiques du foie normal chez le noir africain (A propos de 50 cas sénégalais).

In order to establish the hepatic enzymogram in healthy African black people, four enzymes have been studied in 50 apparently healthy male Africans: transaminases (GOT, GPT), alcaline phosphatases, ornithine carbamoyltransferase (OCT) and gamma-glutamyl transpeptidase (GGT). The findings do not show any difference with the usually admitted levels in European countries, except for alcaline phosphatases which are situated at the upper limit of the normal.