[A risk of developing multiple sclerosis following an outbreak of optic neuritis during a mean follow-up of 4.5 years]. / Riesgo de desarrollar esclerosis múltiple tras un brote de neuritis óptica durante un seguimiento medio de 4,5 años.

OBJECTIVE: The current study was designed to determine the risk of developing clinically definite multiple sclerosis (CDMS) after an isolated idiopathic optic neuritis (ON). PATIENTS AND METHODS: We retrospectively studied 28 patients (range from 18-45 years) who presented a unilateral acute ON between 1 st April and 31 st December. We excluded optic neuropathy of other causes, a previous diagnosis of MS or systemic diseases associated with ON. Patients underwent brain MRI, visual evoked potentials (VEPs), somatosensory evoked potentials (SEPs) and brainstem auditory evoked potentials (BAEPs). The mean interval between ON onset and MRI was 3.1 months. 24 patients were treated with corticosteroids in different ways: oral prednisone (14) and intravenous methylprednisolone (10). Mean duration of the follow-up was 4.5 years in 26 patients. RESULTS: Brain MRI detected white matter areas with increased signal in 10 of 25 patients (40%). Eight (30%) had bilateral anormalities on VEP, while SEPs and BAEPs revealed anormalities in one patient (5.5%). Two out 26 patients (7.7%) developed CDMS; one was treated with oral prednisone and the other with intravenous corticosteroids. No patients with normal MRI developed MS compared to 20% of patients with lesions on initial brain MRI. The only patient with abnormal SEPs and BAEPs did not develop MS. CONCLUSIONS: We found in our population low rate of developing CDMS with higher risk for those ON with abnormalities on initial brain MRI.

Persistent cortical blindness after cyclosporine leukoencephalopathy.

Cyclosporine A (CyA)-related cortical blindness is an uncommon complication of CyA therapy in patients undergoing liver transplantation. Characteristically, neurological symptoms associated with CyA treatment usually regress after cyclosporine withdrawal. We present a case of a liver transplant recipient in whom discontinuation of CyA therapy has resulted in only partial clinical improvement, and cortical blindness remains after 1 year of follow-up. The evolution of cerebral magnetic resonance imaging (MRI) findings over time in this form of CyA leukoencephalopathy is also described.

[Transitory episode of laughter as the initial symptom of an ischemic stroke]. / Episodio transitorio de risa como síntoma inicial de ictus isquémico.

INTRODUCTION: Pathological laughter occurs in pseudobulbar paralysis, in psychiatric disorders and as a sign of convulsions (gelastic crisis). An extremely rare form is the "fou rire prodromique' a pathological episode of laughter preceding a stroke. The pathogenesis is unknown and classically differentiated from gelastic crises. "Fou rire prodromique' has been described in subcortical ischaemic or haemorrhagic strokes, not in cortical strokes. CLINICAL CASE: We describe a patient with an ischaemic cerebrovascular accident due to embolism of the left Sylvian artery. The clinical picture started with a short episode of pathological laughter which preceded sensitive aphasia and weakness of the right limbs. CONCLUSIONS: We suggest that in the case described it is impossible to differentiate between the "fou rire prodromique' and a gelastic crisis as a first sign of an embolic cerebrovascular accident.

[Magnetic resonance of the brain in encephalitis due to Epstein-Barr virus]. / Resonancia magnética cerebral en la encefalitis por virus de Epstein-Barr.

Encephalitis due to Epstein-Barr virus (EEBV) is rare and the debate on possible pathogenic mechanisms has remained open in the absence of structural changes in brain images and discrepancies in serology and viral culture results. We describe an EEBV case in which magnetic resonance images in T1 and T2 potentiated sequences were normal, although intense meningeal captation and a destructive parenchymatous lesion could be observed after administration of gadolinium. These findings suggest direct infiltration of the central nervous system by the virus as well as a meningeal infiltrative type reaction, supporting the hypothesis that the pathogenic mechanisms involved is invasive rather than infectiously or immunologically mediated. The pattern of involvement seen in EEBV by magnetic resonance is different from that of other forms of viral encephalitis.

Effects of lactitol-oligosaccharides on the intestinal microflora in rats.

Lactitol-oligosaccharide (LO) was prepared from lactitol by a transgalactosylation reaction catalyzed by Aspergillus oryzae beta-galactosidase. The utilization of LO by human intestinal bacteria, the digestion of LO by rat jejunum mucosal homogenates and the effects of LO on the intestinal microflora in rats were compared with those of lactitol. 1) LO was utilized in vitro by Bifidobacterium, but lactitol was not utilized. 2) Neither LO nor lactitol were digested by rat jejunum mucosal homogenates. 3) A significant increase in the fecal counts of Bifidobacterium was observed in the LO diets. 4) The concentration of organic acids in feces and cecal contents significantly increased in the LO diets. 5) The concentration of fecal putrefactive products significantly decreased in the LO and lactitol diets. These findings suggest that LO is effective for improving intestinal conditions.

Drift of the sialyl-linkage specific recognition of the sialidase of influenza B virus isolates.

Sialyl-linkage specificity of the sialidase of influenza B viruses isolated in different years from 1940 through 1990 (B/Lee/40,B/Setagaya/3/56,B/Tokyo/7/66,B/Kagoshima/1/68, B/Gifu/2/73, B/Kanagawa/3/76, B/Ibaraki/2/85, B/Yamagata/16/88, and B/Bangkok/163/90) was studied with N-acetylneuraminyl (alpha 2-3)- and (alpha 2-6)-lactoses, GM3 gangliosides containing the same sialyl-oligosaccharide sequences as sialyllactose, and also with type I and type II lacto-series gangliosides carrying Neu5Ac alpha 2-3Gal and NeuAc alpha 2-6Gal linkages as substrates. From an examination of up to nine strains, the sialidases of all viruses preferentially hydrolyze substrates with Neu5Ac alpha 2-3Gal linkage rather than the Neu5Ac alpha 2-6Gal linkage. It was found that the sialidase activity toward Neu5Ac alpha 2-6Gal linkage relative to Neu5Ac alpha 2-3Gal linkage is increased in later strains, whether sialyllactose or ganglioside is used as the substrate. These results suggested that the sialidase of influenza B virus isolates has shown a drift in linkage specificity which correlates with the year of isolation.

Formation of oligosaccharides from lactitol by Aspergillus oryzae beta-D-galactosidase.

Six oligosaccharides were first formed from lactitol by a transgalactosylation reaction catalyzed by Aspergillus oryzae beta-D-galactosidase. From the results of methylation analysis, MS, and 1H- and 13C-NMR studies, it was concluded that these oligosaccharides are O-beta-D-galactopyranosyl-(1----4)-O-beta-D-galactopyranosyl-(1----4)-D- glucitol, O-beta-D-galactopyranosyl-(1----3)-O-beta-D-galactopyranosyl-(1----4)-D- glucitol, O-beta-D-galactopyranosyl-(1----4)-[O-beta-D-galactopyranosyl-(1----6)]- D- glucitol, O-beta-D-galactopyranosyl-(1----6)-O-beta-D-galactopyranosyl-(1---4)- glucitol, O-beta-D-galactopyranosyl-(1----4)-[O-beta-D-galactopyranosyl- (1----5)]-D-glucitol, and O-beta-D-galactopyranosyl-(1----4)-[O-beta-D-galactopyranosyl-(1----1)]- D-glucitol. The last three are newly observed oligosaccharides.