Intracranial aneurysms treated with Guglielmi detachable coils: long-term imaging follow-up with contrast-enhanced magnetic resonance angiography

OBJECT: The aim of this study was to assess the long-term results of intracranial aneurysms treated with Guglielmi detachable coils (GDCs) with the aid of contrast-enhanced magnetic resonance (MR) angiography. METHODS: Between January 1998 and August 2001, 92 patients with 92 aneurysms treated by endovascular coiling with GDCs underwent contrast-enhanced MR angiography. These patients underwent long-term follow-up (range 32-78 months, mean 42.1 +/- 11.9 months [standard deviation]) after endovascular treatment. All images were compared with digital subtraction angiograms and contrast-enhanced MR angiograms that had been obtained during the short-term follow-up (range 5-25 months, mean 13 +/- 5.1 months after treatment). The MR angiograms were analyzed independently by 2 senior radiologists. Findings were assigned to 1 of 3 categories: complete obliteration (Class 1), residual neck (Class 2), or residual aneurysm (Class 3). RESULTS: Of 92 contrast-enhanced MR angiograms obtained at the long-term follow-up, complete obliteration of the aneurysm was noted in 57 patients (Class 1), a residual neck was seen in 22 (Class 2), and a residual aneurysm was observed in 13 (Class 3). One patient experienced aneurysm rehemorrhaging during the follow-up period. The comparison of short- and long-term follow-up angiograms demonstrated a change in aneurysm classification in 7 patients (7.6%), including 4 that progressed from Class 1 to Class 2 and 3 from Class 2 to Class 3. However, 4 (14.2%) of the 28 long-term recurrences were not detected on the short-term control images. CONCLUSIONS: Long-term follow-up with contrast-enhanced MR angiography after selective embolization of intracranial aneurysms can identify late aneurysm recanalization that is undetected at short-term follow-up.     

Nitrite directly vasodilates hypoxic vasculature via nitric oxide-dependent and -independent pathways

Background and purpose:

It is postulated that nitrite requires reduction to nitric oxide in order to exert its relaxant effect upon isolated hypoxic vessels. Herein, we evaluate the relative contribution of nitric oxide and characterize the downstream mechanisms of nitrite-induced vasorelaxation.

Experimental approach:

Aortic rings were treated with pharmacological agents and exposed to hypoxia (<1% O₂). Following pre-constriction, nitrite (10 µM final) was added to appropriate baths; isometric tension was recorded throughout.

Key results:

Nitrite (under hypoxic conditions at physiological pH) is capable of exerting physiological effects that cannot be completely inhibited by the inhibitor of soluble guanylate cyclase (sGC), 1H [1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one or a nitric oxide scavenger (carboxy-2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide). Simultaneous blockade of both sGC and cyclooxygenase (COX) completely inhibited the response to nitrite. With regard to the nitric oxide-dependent component, we confirm that aldehyde oxidase, but not xanthine oxidase or endothelial nitric oxide synthase, was important for the actions of nitrite in our model.

Conclusions and implications:

Nitric oxide generated from nitrite is not exclusively responsible for the physiological actions observed in isolated hypoxic vessels. Nitrite operates via different pathways dependent on the presence or absence of endothelium to produce vasorelaxation. In intact vessels, both sGC and COX enzymes appear to be important. Irrespective of this difference in relaxation mechanism, nitrite is capable of producing the same maximum relaxation, regardless of the presence of endothelium. Having investigated possible nitrite reduction sites, we confirm that aldehyde oxidase is important for the actions of nitrite.     

Rapid detection of the major deletion in the Batten disease gene CLN3 by allele specific PCR.

The recent isolation of the CLN3 gene involved in Batten disease (juvenile neuronal ceroid lipofuscinosis) creates possibilities for direct detection of mutations which can confirm or indicate the clinical diagnosis of Batten disease. We have designed a rapid and reliable allele specific PCR test for the detection of the major deletion, which can be used in carrier diagnosis, presymptomatic diagnosis, and prenatal diagnosis.