A two-decade experience of head and neck paragangliomas in a whole population-based single centre cohort

Paragangliomas are rare neuroendocrine tumours arising from neural crest-derived tissue. In the head and neck region typical locations are the carotid bifurcation, vagal nerve or jugulotympanic region. Paragangliomas are normally benign, and malignant transformation is rare. During the past decade the understanding of the genetic and molecular aetiology has had an important clinical impact on the management of PGs. This is a retrospective review of all histologically verified paragangliomas diagnosed and managed at an academic tertiary care referral centre between 1990 and 2010. Data on age, sex, symptoms, tumour location, management and follow-up were recorded. There were 64 patients with 74 tumours. Thirty-six per cent of the tumours were located in the carotid body region, 48 % in the jugulotympanic region and 15 % in the vagal nerve. One tumour was located in the dorsal neck. Most (95 %) of the patients were treated primarily with surgery and with curative intent. Definitive radiation therapy was primarily given to two patients. Recurrent or residual tumours were treated with surgery in three patients and with radiation therapy in nine patients. The typical long-term post-operative sequel was vocal cord paralysis. Local recurrence was found in 6 % of patients. Symptoms and findings related to paragangliomas are variable and management should be individualized. Surgery remains the primary choice of the current treatment options, but often is challenging and warrants a multidisciplinary approach. We present an algorithm on the management of head and neck paragangliomas based on current knowledge.

Cystic dilation of the distal end of the nasolacrimal duct: underrated cause of epiphora in adults and its endoscopic treatment

Epiphora is a frequent reason for ophthalmologic consultation. Among the multiple causes, obstructions of the lacrimal excretory system are common. Sacal and postsacal obstructions are much more frequent than presacal obstructions. Obstruction at the level of the Hasner's valve is rare and likely underestimated. The authors report the clinical history and the imaging of 3 patients with a cystic dilation of the distal end of the nasolacrimal duct (NLD). These patients were easily managed by an ENT surgeon. In one case, the surgery consisted of an endonasal DCR where in the 2 other cases, a marsupialisation of the cystic expansion of the nasolacrimal duct was successfully performed with the micro- debrider. The authors review the world literature on this specific topic. They conclude that a coronal sinus CT scan and an inferior meatus endoscopy should be included in the ophthalmologic work-up performed in all cases of low obstruction of the lacrimal system. When there is a dilation of the distal end of the NLD the marsupialisation of the cystic expansion in the inferior meatus is the option of treatment instead of performing a DCR. ENTs must play a role in the assessment and treatment of low obstructions of the lacrimal excretory system.

Relationships between nitric oxide-mediated endothelial function, eNOS coupling and blood pressure revealed by eNOS-GTP cyclohydrolase 1 double transgenic mice

Endothelium-dependent relaxation in conduit vessels is mediated largely by nitric oxide (NO), produced by the enzyme endothelial nitric oxide synthase (eNOS) in the presence of the cofactor tetrahydrobiopterin (BH4) and mediated through a cGMP-dependent downstream signalling cascade. Endothelial NOS regulates blood pressure in vivo, and impaired endothelial NO bioactivity in vascular disease states may contribute to systemic hypertension. In the absence of sufficient levels of the cofactor BH4, NO becomes uncoupled from arginine oxidation and eNOS produces superoxide rather than NO. The enzymatic uncoupling of eNOS is an important feature of vascular disease states associated with increased oxidative stress. However, whether eNOS coupling, rather than overall eNOS activity, has specific effects on endothelium-dependent vasorelaxation in vitro, or on blood pressure regulation in vivo, remains unclear. In this study, we evaluate the relationships between blood pressure and endothelial function in models of eNOS uncoupling, using mice with endothelium-targeted transgenic eNOS overexpression (eNOS-Tg), in comparison with littermates in which eNOS coupling was rescued by additional endothelium-targeted overexpression of GTP cyclohydrolase 1 (eNOS/GCH-Tg) to increase endothelial BH4 levels. Despite the previously characterized differences in eNOS-dependent superoxide production between these animals, we find that blood pressure is equally reduced in both genotypes, compared with wild-type animals. Furthermore, both eNOS-Tg and eNOS/GCH-Tg mice exhibit similarly impaired endothelium-dependent vasorelaxation. We show that reduced vasorelaxation responses result from desensitization of cGMP-mediated signalling and are associated with increased NO production rather than changes in superoxide production.

Different effects of acute administration of aminophylline and nitroglycerin on exercise capacity in patients with syndrome X

To investigate the effects of the acute administration of aminophylline and nitroglycerin on effort ischemia, 20 patients with syndrome X underwent 3 bicycle exercise tests after sublingual nitroglycerin (0.3 mg) and after 90 minutes of oral administration of aminophylline (400 mg). Compared with the basal test, only aminophylline induced a significant increase in the time to ischemic threshold and to angina; these findings support the potential therapeutic role of this adenosine receptor blocking agents and suggest a possible role of "steal phenomenon" in the pathogenesis of effort angina in patients with syndrome X.