Effects of adrenergic agents on transepithelial electrical measurements across the isolated iris-ciliary body.

Transmembrane electrical measurements were performed on the isolated rabbit iris-ciliary body to study direct effects of adrenergic drugs on the ciliary epithelium. Alpha-adrenergic agonists (epinephrine, norepinephrine, or phenylephrine) lowered the short-circuit current (SCC) in a dose-dependent fashion relative to which chamber side the drug was added: simultaneous addition to both chambers greater than blood side only greater than aqueous side only. Pretreatment (5 x 10(-5) M) with the non-selective beta-adrenergic antagonist timolol had no effect while the non-selective alpha-adrenergic antagonist, phentolamine, completely prevented the alpha agonist-induced decrease in SCC. The alpha-adrenergic response was mediated by the alpha 1 subtype since prazosin, but not yohimbine, blocked the induced reduction in SCC. The beta-adrenergic agonist isoproterenol caused a dose-dependent decrease in the SCC. The decrease was similar when the drug was added to only the blood side or to both sides of the chamber. Addition to only the aqueous chamber had no effect. Pretreatment with beta-adrenergic antagonists blocked the isoproterenol response: non-selective = selective beta 2 greater than selective beta 1. The isoproterenol-induced decrease in SCC was also blocked by non-selective alpha-adrenergic antagonists. The response was mediated by the alpha 1 subtype since prazosin, but not yohimbine, blocked the isoproterenol response. This suggests that isoproterenol interacted with the alpha 1-adrenergic sensitive pathway in the rabbit ciliary process.     

Combined endovascular and surgical treatment of fusiform aneurysms of the basilar artery: technical note

Background

To present the combined treatment of fusiform basilar artery aneurysms consisting of a surgical posterior fossa decompressive craniectomy and ventriculoperitoneal (VP) shunt operation at the same sitting, before the endovascular procedure with telescopic stenting of the aneurysmatic vessel segment in four cases.

Methods

Combined treatment involving surgical procedure consisting of ventriculoperitoneal shunt placement for hydrocephalus and an occipital bone craniectomy and C1 vertebrae posterior laminectomy to decompress the posterior fossa in the same session. After surgery, the patients were loaded with acetylsalicylic acid and clopidogrel, and then the endovascular treatment was performed.

Results

All of the procedures were performed successfully without technical difficulty. The patients tolerated the procedures well and all cases showed remodelling with the overlapping stent technique. The patients were discharged home with baseline neurological situation and computed tomography (CT) angiography was performed at the 3rd month.

Conclusion

This technique is a safer endovascular approach to treating symptomatic fusiform basilar artery aneurysms by protecting patients from both the haemorrhagic complications of anticoagulant therapy and thrombotic complications due to the interruption of anticoagulant therapy, while treating the hydrocephalus and compression by surgical means.     

The retreatment: Indications,technique and results

Durability of endovascular treatment of intracranial aneurysms has always been an issue and a very strong point of criticism. Although studies on long-term results have made it clear that endovascular treatment safe and effective they, nonetheless showed retreatment after endovascular treatment is nearly 5–10 times more frequent than surgical clipping. Risk factors predisposing high probability of retreatment are aneurysm with dissecting nature, incomplete coiling, sac size larger than 10 mm and localization at the bifurcations such as basilar tip. The indications for retreatment after endovascular treatment are not clear yet, although certain morphologic criteria can be used. Retreatment appears not to negate the initial advantage of endovascular treatment over surgical treatment and can be performed very small morbi-mortality numbers.     

Spinal dural involvement in Erdheim-Chester disease: MRI findings

There are very few reported cases of Erdheim-Chester disease that document involvement of dura at the level of the spinal cord. Among these reports, we know of no publication that includes detailed MRI findings. To the best of our knowledge, the case presented here is the first published report of this specific manifestation of Erdheim-Chester disease that includes detailed MRI findings in addition to the related history. Spinal manifestations of Erdheim-Chester disease in our patient were at the dorsal and lumbar levels (T1-T6 and T12-T11 respectively). Both epidural and subdural linear large masses were present, causing spinal cord compression at the dorsal level and epidural thickening at the lumbar level.     

An alternative technique of the superselective catheterization of the ophthalmic artery for intra-arterial chemotherapy of the retinoblastoma: retrograde approach through the posterior communicating artery to the ophthalmic artery

Introduction

Superselective intra-arterial chemotherapy (IAC) in retinoblastoma has recently become a popular treatment option. In this study, we purposed to investigate the effectiveness of the technique of “retrograde approach through the posterior communicating artery to the ophthalmic artery (OA)” for IAC.

Methods

A total of 12 unilateral retinoblastomas were treated with IAC in 29 sessions from October 2011 to November 2013. Of the 12 patients, 6 were male and 6 were female, with ages ranging from 12 to 72 months with a median age of 27.6 months. Left-to-right ratio for affected eye was 6/6. In the first 4 patients, we used the ipsilateral internal carotid artery (ICA) to reach the OA of the affected globe (10 sessions). Then, we used the vertebral artery, basilary artery, ipsilateral/contralateral P1 segment of the posterior cerebral artery, and ipsilateral/contralateral posterior communicating artery, respectively, to reach inside the OA at next 15 sessions.

Results

At ipsilateral approach, fluoroscopy total time ranged from 16 to 34 min (mean 21.5 min), and the angle between ophthalmic segment of the ICA and proximal segment of the OA was ranged between 34° and 77° with an average angle of 53.4°. At retrograde approach, fluoroscopy total time ranged from 3 to 12 min (mean 7.5 min), and the angle between ophthalmic segment of the ICA and proximal segment of the OA was ranged between 147° and 178° with an average angle of 148.3°.

Conclusion

Retrograde approach makes the IAC procedure easier in retinoblastoma patients and shortens the fluoroscopy time.