Reversal of Cerebral Vasospasm by the Nitric Oxide Donor SNAP in an Experimental Model of Subarachnoid Haemorrhage

The constant release of nitric oxide (NO) is essential to maintain basal cerebrovascular tone. Oxyhaemoglobin, liberated by lysis of red blood cells after subarachnoid haemorrhage binds NO and prevents its entry into vascular smooth muscle cells. While endothelium-dependent vasoconstriction is preserved, decreased levels of NO inhibit endothelium-dependent relaxation and may cause vasospasm. S-nitrosothiols are potent vasodilators and precursors of NO. The authors' aim was to determine whether S-nitroso-N-acetylpenicillamine (SNAP), a stable S-nitrosothiol compound, could reverse vasospasm in an experimental vasospasm model in rabbit. Experimental subarachnoid haemorrhage (SAH) was induced in 37 New Zealand white rabbits. The animals were divided into four groups. Control (no SAH), SAH only, SAH plus saline and SAH plus SNAP. SNAP (15 micrograms/kg/min) or 0.09% saline (equal volume) was infused 46 hours after induction of SAH. All animals were killed by perfusion fixation 48 hours after SAH occurred. Basilar arteries were removed, sectioned and their cross sectional areas were evaluated in a blind manner, by light microscopy and by using computer assisted morphometry. Experimental SAH elicited vasospasm in all animals of SAH only and SAH plus saline group. In animals treated with SNAP, arterial narrowing was markedly attenuated without producing systemic hypotension. This widening achieved statistical significance when compared to the arteries of the SAH only and SAH plus saline group (p < 0.01). This study indicates that the NO donor SNAP is a potentially useful drug to reverse cerebral vasospasm due to SAH.     

Videolaparoscopic treatment of liver hydatid cysts with partial cystectomy and omentoplasty

Hydatid disease is one of the world's most important health problems. Although several conservative approaches have been used for the management of this condition, surgery remains the ideal choice in most of the cases. Videolaparoscopic approach can safely be applied for the management of liver hydatid cysts if several precautions are undertaken. In this study, we present two liver hydatid cyst cases successfully treated with partial cystectomy and omentoplasty using videolaparoscopic approach.     

Posterior fossa pseudotumour due to viral encephalitis in a child

A 14-year-old boy had a 1-month history of diplopia (due to a VI nerve palsy), motor ataxia and dizziness. Brain MRI showed a 1.5-cm mass posterior to the pons. Histopathological examination of a biopsy specimen showed the lesion to be of viral origin. After 3 months, the ataxia and dizziness had resolved and the MRI findings returned to normal. By 5 months the abducens paralysis had also resolved. Viral encephalitis should be considered in the differential diagnosis of posterior fossa tumours. Received: 20 March 1997 Accepted: 16 April 1997     

Neuroprotective and symptomatological action of memantine relevant for alzheimer’s disease — a unified glutamatergic hypothesis on the mechanism of action

The involvement of glutamate mediated neurotoxicity in the pathogenesis of Alzheimer's disease is finding increasingly more acceptance in the scientific community. Central to this hypothesis is the assumption that in particular glutamate receptors of the N-methyl-D-aspartate (NMDA) type are overactivated in a tonic rather than a phasic manner. Such continuous mild activation leads under chronic conditions to neuronal damage. Moreover, one should consider that impairment of plasticity (learning) may result not only from neuronal damage per se but also from continuous activation of NMDA receptors. To investigate this possibility we tested whether overactivation of NMDA receptors using either non-toxic doses/concentrations of a direct NMDA agonist or through an indirect approach--decrease in magnesium concentration--produces deficits in plasticity. In fact NMDA both in vivo (passive avoidance test) and in vitro (LTP in CA1 region) impaired learning and synaptic plasticity. Under these conditions memantine which is an uncompetitive NMDA receptor antagonist with features of "improved magnesium" (voltage dependence, affinity) attenuated the deficit. The more direct proof that memantine can act as a surrogate for magnesium was obtained in LTP experiments under low magnesium conditions. In this case as well, impaired LTP was restored in the presence of therapeutically relevant concentrations of memantine (1 microM). In vivo, doses leading to similar brain/serum levels produce neuroprotection in animal models relevant for neurodegeneration in Alzheimer's disease such as neurotoxicity produced by inflammation in the NBM or beta-amyloid injection to the hippocampus. Hence, we postulate that if in Alzheimer's disease overactivation of NMDA receptors occurs indeed, memantine would be expected to improve both symptoms (cognition) and slow down disease progression because it takes over the physiological function of magnesium.     

Acute Lymphoblastic Leukemia as a Second Malignant Neoplasm in a Child with Medulloblastoma

Second malignant neoplasm in childhood is increasing due to advances in therapy modalities. Acute lymphoblastic leukemia as a second malignancy following the treatment of medulloblastoma is a very rare condition. A 13-year-old boy was diagnosed as acute lymphoblastic leukemia following radiotherapy and chemotherapy for treatment of medulloblastoma.     

An unexpected complication of acute pancreatitis: Intra-cardiac thrombus

Left atrial thrombus after acute pancreatitis (AP) is a rare clinical statement. Because of induction of systemic prothrombotic process by AP; some patients with underlying risk factors may develop an intra-cardiac thrombus. We present a 53 years-old-woman with moderate mitral stenosis and atrial fibrillation. However the patient was under warfarin treatment, she developed a big left atrial big thrombus which was originated from left atrial appendage after she was suffered from AP.     

Caligus mulli n. sp. (Copepoda: Caligidae) parasitic on two Mullid fishes from the eastern Mediterranean and adjacent Atlantic waters

Parasitology Research - A new species of caligid copepod, Caligus mulli n. sp., is described based on specimens collected from surmullet Mullus surmuletus Linnaeus from Atlantic waters off the...