Central nervous system superficial siderosis, headache, and epilepsy.

Almost 95 cases of superficial siderosis of the central nervous system have been reported in the literature. These patients showed a clinical syndrome characterized by ataxia, deafness, pyramidal system involvement, and mental deterioration with xanthochromic cerebrospinal fluid and neuroradiological findings of hemosiderin deposits. About 30% of the patients had headache as an accompanying symptom. In the present case report, we describe a 33-year-old man with the typical clinical features of superficial siderosis, who complained, since aged 8, of a severe recurrent frontal headache often associated with loss of consciousness occurring after at least 2 hours of pain. The MRI and CSF findings were consistent with subarachnoid bleeding. In our patient, headache due to meningeal irritation by subarachnoid blood induced seizures as a probable reflex of extreme pain. Carbamazepine and nimodipine prophylaxis dramatically reduced the frequency of headaches and seizures.

Neuroprotective effects of felbamate on global ischaemia in Mongolian gerbils.

Felbamate is an antiepileptic drug whose action appears to occur mainly through an interaction with neurotransmission mediated by excitatory amino acids. We assessed its effectiveness in a model of transient global ischaemia in Mongolian gerbils. Dizocilpine (MK 801) was used for comparison. Treatment was given 10 min after transient forebrain ischaemia which was performed by occluding both common carotid arteries for 10 min. Felbamate (300 mg/kg i.p.) increased the number of surviving neurons in the CA1, CA2 and CA3 hippocampal cells. In particular, the CA1 area had a significantly higher number of surviving pyramidal neurons than that of vehicle-treated animals (67 +/- 11 vs 33 +/- 6 surviving neurons/mm; P < 0.05). No significant difference in density of surviving neurons was observed between dizocilpine (3 mg/kg i.p.) and vehicle (54 +/- 10 vs 33 +/- 6 surviving neurons/mm). The EEG results indicated that the effect of felbamate, used alone, is the same in the ischaemic-vehicle group as non-ischaemic group. Our results show that felbamate exerts neuroprotective effects in a model of severe cerebral ischaemia.

Response variability to ischemic injury in the Mongolian gerbil: an electroencephalographic and behavioral study.

The early effects of 5 or 10 min global cerebral ischemia, sham operation and halothane anesthesia were evaluated in Mongolian gerbils by means of electroencephalography (EEG), neurological examination and passive avoidance training. The "ischemia-sensitive" gerbils (33% and 64% of the 5 and 10 min ischemic groups, respectively) died during carotid ligation or within 24 h; the "ischemia-resistant" gerbils showed variable behavioral responses. Six hours after ischemia, all of the animals presented EEG activity characterized by increased delta (1-4 Hz) activity and a decreased theta 2 (6-9 Hz) band, with a tendency to recovery at 24 h. Learning impairment was observed in 5 of the 5 min ischemic animals (83%) and in 1 sham (17%) and 1 halothane (17%) control. Fourteen days after ischemia, histologic damage was observed in 4 ischemic gerbils and 1 sham control. On the whole, this study confirms the widely variable susceptibility of gerbils to cerebral ischemia. Moreover, although the variable effects of carotid occlusion have been attributed to multiple factors involving the cerebrovascular system, our data suggest that endogenous cellular mechanisms might protect against ischemia. In view of this consideration, it would be useful to investigate the molecular causes of the variable cerebral ischemic tolerance shown by Mongolian gerbils.

Connective tissue proliferation and growth factors in animal models of Duchenne muscular dystrophy.

The difference in the lifespan of dy and mdx mice could be due to different muscle regeneration capabilities. In mdx an involvement of bFGF in stimulating regeneration has been postulated. The aim of our work was to detect the presence, and to study the distribution, of muscular and connective tissue growth factors in mdx and dy mice at different stages of muscle pathology. From 7 to 10 weeks of age the difference between the two dystrophic mice becomes evident. At 13 weeks the dy mouse presents a predominance of fibrosis and degenerative muscular phenomena while the main pathological feature in mdx mouse is the muscle regeneration. In both animal models fibrosis proliferation is correlated to the presence of EGF and its receptor and TGF beta 1. bFGF was localized to regenerating and degenerating fibers in both dy and mdx mice. The bFGF presented a normal pattern in mdx mice at 20 weeks when regenerative and degenerative phenomena were no longer present. Our data suggest that growth factors could influence the outcome of muscular regenerative and degenerative processes.

Morphological and functional evaluation of peripheral nerve regeneration in the rat using an expanded polytetrafluoroethylene (PTFE) microprosthesis.

The aim of our study was to evaluate in the rat the ability of a polytetrafluoroethylene microprosthesis (PTFE), to guide the peripheral nerve regeneration between the two extremities of a transected sciatic nerve. In 15 adult male Wistar rats, weighing 200 g, a segment of the right sciatic nerve was resected, leaving a gap of about 1 cm, bridged with microprosthesis, using our original microsurgical technique. Neurophysiological evaluations were performed at 6 and 9 months post-operatively to study the distal motor latency either in the right sciatic nerve or in the unoperated control side. In all the rats myoelectrical responses with an increased latency of the operated side were produced from the interosseous muscle of the foot. The animals were sacrificed 9 months post surgery. Histological sections at the level of the graft were done in all the rats, and in 10 animals biopsies of the tibialis anterior muscle (TA) of each side were performed. An active process of axonal regeneration was documented inside the graft, with no infiltration of nerve fibers through the wall of the prosthesis. A connective fibrous reaction was present around the external wall of the graft. Muscle biopsies showed definite signs of muscle reinnervation, with residual features of variable degree of denervation. These findings stress and confirm the ability of the PTFE graft to allow effective regeneration in a peripheral nerve gap in the rat.