Although approximately 20% of the patients did not have MR imaging abnormalities, MR imaging did show signal intensity alterations due to gliosis and spongiform changes early in the course of CJD in the remaining 80%. The demonstration of bilateral areas of increased signal intensity that predominantly affected the caudate nuclei and the putamina on long-repetition-time MR images in an elderly patient with rapidly progressive dementia represents a specific finding and clearly should suggest the diagnosis of CJD.
The lysis gene region of bacteriophage lambda, including genes S, R, and Rz, was cloned into the plasmid pBH20. In the recombinant plasmid, the lysis genes are expressed under the control of the lacOP region. Induction of this "lysis operon" with the lac inducer, IPTG, under conditions where transcription from the lacOP region is not subject to catabolite repression, results in a sharply defined lysis after 35 min. Premature lysis can be accomplished by cyanide, chloramphenicol, or chloroform, exactly as in bacteriophage lambda infected cells. The lysis gene region of an S- mutant was also cloned into pBH20. Induction of the S- lysis operon has no apparent effect on culture growth; however, large quantities of bacteriolytic activity accumulate intracellularly. Neither cyanide nor chloramphenicol causes lysis in the induced S- clones. Thus premature lysis appears to be entirely an S-dependent phenomenon. A model for the control of lysis in bacteriophage lambda infections is presented in which it is the accumulation of the S gene product in competition with a host "anti-S" protein that determines lysis timing.
We describe two patients who presented with dementia as the primary neurological manifestation of their dural arteriovenous fistula (dAVF). Although dementia is not the most common presentation for a dAVF, these cases show that obliterating the fistula can eliminate this dreadful manifestation. This awareness may facilitate the diagnosis of dementia in cases caused by dAVF and allow for a minimally invasive treatment that restores cognitive function back to baseline.
Gliosarcoma exhibits some characteristic MR features. It should be included in the differential diagnosis of any tumor that appears to be intraaxial but abuts a dural surface and is much less hypointense on T2-weighted images than other glial neoplasms.
Dural arteriovenous fistulae are rare lesions composed of abnormal connections between meningeal arteries and the dural sinuses or lepto-meningeal veins. Treatment is challenging because of the small size and wide distribution of the myriad sites of fistulous connection. We present a case of a dural arteriovenous fistula presenting with visual deterioration, pulsatile tinnitus, and intracranial hypertension that was successfully treated with a multidisciplinary approach combining angiographic, surgical, and radiosurgical intervention. This is one of the largest of these formidable lesions treated in this fashion that has been reported.
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