Progressive multifocal leukoencephalopathy in patients with AIDS: appearance on MR images

Progressive multifocal leukoencephalopathy (PML) is an uncommon demyelinating disease that occurs in immunocompromised patients. The authors evaluated magnetic resonance (MR) images of 10 patients with pathologically proved PML and clinically diagnosed acquired immunodeficiency syndrome (AIDS) to determine the MR characteristics of this disorder. All patients had asymmetric cerebral involvement. Lesions were distributed throughout the brain, including the brain stem and basal ganglia. White matter was affected in all 10 patients; gray matter was also involved in five. In one patient the lesion enlarged and crossed the corpus callosum and contained focal hemorrhage. The authors conclude that, contrary to reported findings on computed tomographic scans, PML in patients with AIDS has a variable appearance on MR images and has many characteristics that differ from those previously thought to be typical on imaging studies.     

Experimental study of fulguration of healthy ventricle. II. Chronic lesions]

The effect of fulguration shocks was studied using healthy ventricular myocardium of 12 pigs weighing between 63 and 100 kg. With shocks of equal energy to those used clinically, lesions seen 24 hours after the session in two pigs showed the formation of loose fibrosis and of marked cellular infiltration as well as zones of hypercontraction with calcium precipitation. The size of chronic lesions seen during periods ranging from one week to 2 months was studied in 4 pigs. Transmural plaques with a diameter of 1.5 to 2 cm were seen in the right ventricle. For the same energy levels of 240 Joules delivered to left ventricular tissue, lesions were of the same size but were never transmural. Under certain conditions, lesions were disposed in the direction of the neutral electrode.     

Oesophageal foreign bodies.

Impaction of foreign bodies in the oesophagus was analysed in 54 patients, 45 of whom were children. Of the 45 children 28 were aged 2-4 years. Coins were the most common foreign body in children (27 cases) while in adults a bolus of meat was most common (nine cases). In 41 children there was no predisposing factor, but an underlying mechanism was detected in 88% of the adults. The mechanisms were of three types: oesophageal (stricture), neuromuscular (myasthenia gravis), and extrinsic and mechanical (ankylosing spondylitis). In children most of the foreign bodies were impacted in the upper oesophagus at the cricopharyngeal junction, which is the narrowest part of the oesophagus, while in adults the foreign body was usually impacted at the site of the predisposing lesion or in the lower oesophagus. In all patients oesophagoscopy was performed under general anaesthesia to remove the impacted foreign body. Complications were more frequent in adults, mainly owing to the underlying condition.     

Squamous carcinoma of the posterior pharyngeal wall

We present 70 patients with tumours of the posterior pharyngeal wall, considering tumours of the posterior hypopharyngeal and posterior oropharyngeal wall as one unit. Almost half (45%) of the patients were in poor general condition at the time of presentation, and 60% had Stage III or IV tumours. One-third of the patients were untreated, and surgery was mainly reserved for patients with Stage I and II tumours. The larynx could be preserved in two-thirds of those undergoing surgery. The best current method of repair of the posterior pharyngeal wall after partial pharyngectomy appears to be a revascularized radial forearm flap. The median survival for patients with Stage I tumours was 236 weeks, but for patients with Stages II-IV tumours was only 33 weeks. There was no significant difference between the survival for II–IV stage groups, but there was between Group I and the rest. We identify 2 defects in the UICC classification system: lack of definition of the lateral limit of the posterior pharyngeal wall, and a gross discrepancy between size and T staging of tumours arising primarily from the posterior wall of the hypopharynx.     

Orotic Acid Improves Recovery of Left Ventricular Function Days After Heterotopic Transplantation

The preclinical evidence for a potential influence of calcium channel blockers (CCBs) on carcinogenesis is discussed in the light of a broad database from rodent carcinogenicity studies as well as literature data. In all bioassays performed in rats and mice on the dihydropyridine CCBs — nifedipine, nimodipine, nisoldipine, and nitrendipine — no evidence was found for a carcinogenic potential of these compounds. Calcium is an essential intracellular signal for cell proliferation and apoptosis. The crucial role of increased cell proliferation in all stages of carcinogenesis is well documented. Some indirect experimental evidence also points to a role of defective apoptosis in tumor promotion. CCBs uniformly inhibit cell proliferation, whereas the influence of CCBs on apoptosis is inconsistent, resulting in an inhibition or increase in apoptosis dependent on cell type. Accordingly, antitumorigenic effects of CCBs have been reported based on their antiproliferative action. A tumor-promoting effect of CCBs based on inhibition of apoptosis, however, remains purely speculative and, in fact, can be denied based on the results of in vivo bioassays. It is therefore concluded that there is no preclinical evidence that should give rise to concern over the carcinogenic potential of dihydropyridine-type CCBs.