Phosphodiesterase 5 inhibition attenuates cerebral vasospasm and improves functional recovery after experimental subarachnoid hemorrhage.

BACKGROUND: Cerebral vasospasm is an independent predictor of poor outcome after subarachnoid hemorrhage (SAH). The nitric oxide-cyclic guanosine monophosphate (NO-cGMP) vasodilatory pathway is strongly implicated in its pathophysiology. Preliminary studies suggest that phosphodiesterase 5 (PDE5), an enzyme that degrades cGMP, may play a role because the PDE5 inhibitor sildenafil was found to reduce vasospasm after SAH. However, several questions that are critical when considering translational studies remain unanswered. OBJECTIVE: To elucidate the mechanism of action of sildenafil against vasospasm and to assess whether sildenafil attenuates SAH-induced neuronal cell death, improves functional outcome after SAH, or causes significant physiological side effects when administered at therapeutically relevant doses. METHODS: SAH was induced via endovascular perforation in male C57BL6 mice. Beginning 2 hours later, mice received sildenafil citrate (0.7, 2 or 5 mg/kg orally twice daily) or vehicle. Neurological outcome was assessed daily. Vasospasm was determined on post-SAH day 3. Brain PDE5 expression and activity, cGMP content, neuronal cell death, arterial blood pressure, and intracranial pressure were examined. RESULTS: We found that PDE5 activity (but not expression) is increased after SAH, leading to decreased cGMP levels. Sildenafil attenuates this increase in PDE5 activity and restores cGMP levels after SAH. Post-SAH initiation of sildenafil was found to decrease vasospasm and neuronal cell death and markedly improve neurological outcome without causing significant physiological side effects. CONCLUSION: Sildenafil, a US Food and Drug Administration-approved drug with a proven track record of safety in humans, is a promising new therapy for vasospasm and neurological deficits after SAH.

Endoscopic management of intraventricular neurocysticercosis.

Surgical management is the only option for patients presenting with acute hydrocephalus caused by intraventricular neurocysticercosis. Although various modalities have been described, endoscopic excision is becoming increasingly popular. The outcomes for 22 patients with intraventricular neurocysticercal cysts with hydrocephalus managed endoscopically are presented. Complete excision of cysts (fourth ventricle, 14; lateral ventricle, 4; third ventricle, 3; both lateral and third ventricles, 1) was performed in all patients. Internal procedures for cerebrospinal fluid diversion were performed in 20 patients. There were minimal perioperative complications, all patients were relieved of raised intracranial pressure and no patient has required shunting to date. Mean follow-up duration was 20.7 months. Follow-up imaging showed the absence of residual cysts and resolution of hydrocephalus in all patients.

Transventricular, transaqueductal scope-in-scope endoscopic excision of fourth ventricular neurocysticercosis: a series of 13 cases and a review.

OBJECT: Neurocysticercosis (NCC) is the most common parasitic infestation of the central nervous system worldwide. In patients presenting with acute hydrocephalus due to intraventricular NCC, surgery is the only option. Still, there is no consensus regarding the optimal surgical strategy, although neuroendoscopic excision is a promising method. However, the literature regarding the use of this modality in fourth ventricular NCC is scarce. The authors describe a series of patients with fourth ventricular NCC treated endoscopically. METHODS: The clinical records of 13 patients with fourth ventricular NCC who had presented with hydrocephalus were retrospectively analyzed. A fourth ventricular cyst was completely excised in all patients by using a transventricular, transaqueductal "scope-in-scope" endoscopic technique. Twelve endoscopic third ventriculostomies and 1 septostomy had been performed. RESULTS: Shunt placement was avoided in all patients. There were minimal peri- and postoperative complications. The mean duration of follow-up was 22.3 months (range 3-41 months). All patients had an improved clinical outcome. Follow-up neuroimaging revealed no residual lesion and a decreased ventricle size in all patients. CONCLUSIONS: The present series of patients with fourth ventricular NCC is the largest in the existing English-language medical literature. Endoscopic fourth ventricular cysticercal cyst excision along with internal cerebrospinal fluid diversion via endoscopic third ventriculostomy is an effective alternative to open microneurosurgical procedures and avoids shunt placement and its related complications.

Endoscopic excision of intraventricular neurocysticercosis in children: a series of six cases and review.

OBJECTS: Neurocysticercosis (NCC) affects both adults and children, but it is uncommon in childhood. The clinical presentation and management of intraventricular neurocysticercosis (IVNCC) in children has not been described adequately. We, therefore, present our series of six children with IVNCC managed by endoscopic excision. MATERIALS AND METHODS: A retrospective analysis of six children with IVNCC was performed. The endoscopic technique practiced is described. Complete excision of the intraventricular cyst was performed in all patients. Simultaneously, five endoscopic third ventriculostomies, one septostomy, and one foramenotomy were performed. There were no perioperative and postoperative complications. Mean follow-up duration was 24.8 months. Clinical improvement was seen in all children, and none required shunting. Follow-up radiology showed no residual lesion and decreased ventricle size in all patients. CONCLUSION: Endoscopic IVNCC cyst excision along with internal CSF diversion is a safe and effective option and avoids shunt and its related complications in these children.

Role of PET/PET-CT in the management of sarcomas.

Positron emission tomography (PET) is a functional diagnostic imaging technique that provides very different information from that obtainable with other imaging modalities. The most widely used radiotracer is F-18 fluoro-2-deoxy-D-glucose (FDG), which is an analog of glucose. The FDG uptake in cells is directly proportional to glucose metabolism, which is increased many times in malignant cells. FDG-PET is now the standard of care in initial staging, monitoring the response to therapy and management of various cancers (e.g., breast cancer, lung cancer and lymphoma). However, the paucity of anatomical landmarks on PET images makes a consistent hardware fusion to anatomical cross-sectional data extremely useful. The introduction of combined PET-computer tomography (CT) scanners, which provide not only functional, but also structural information leading to a detection of subcentimeter lesions, made this technique useful in the early detection of the disease process and decreasing false-positive lesions. The aim of this article is to review the clinical applications (i.e., diagnosis, staging, evaluation of treatment response and restaging) using PET in patients with bone and soft-tissue sarcoma.