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Superficial siderosis of the central nervous system (SSCNS) is a rare syndrome resulting from hemosiderin deposits in neuronal tissues close to the cerebrospinal fluid. SSCNS is characterized by sensorineural deafness, cerebellar ataxia and signs of pyramidal tract dysfunction. The present study describes a patient with SSCNS that did not suffer from hearing loss, which is the most common symptom of SSCNS. The patient was a 48-year-old male, presenting with dizziness, ataxia and slurred speech. The patient's ataxia was characterized by dizziness, nystagmus, dysarthria, abnormal finger-nose pointing and heel-knee-shin tests and a positive Chaddock sign. The patient had suffered from a pontine hemorrhage two years prior to the study. Audiometric tests showed normal hearing during the hospital stay and at the two-month follow-up examination. The diagnosis of SSCNS was made based on magnetic resonance images, which showed areas of linear hypointensity on the surface of the pons with mild cerebellar atrophy. However, a long-term follow-up is required to monitor the hearing of the patient. Improved understanding of SSCNS is important for clinicians to identify SSCNS patients who present without typical clinical symptoms. [ABSTRACT FROM AUTHOR]

This study describes the case of a 41-year-old woman admitted for anterograde memory loss, right facial grimacing and right arm posturing that had begun 1 month previously. Cranial magnetic resonance-diffusion weighted imaging and -fluid-attenuated inversion recovery imaging revealed a hyperintense signal in the left hippocampus and right basal ganglia, but no contrast enhancement. An electroencephalogram revealed rhythmic sharp and slow waves and rhythmic ? build-ups in the left temporal area. Single-photon emission computed tomography showed increased regional blood flow perfusion in the left cerebral frontal lobe and the right basal ganglia. The cerebrospinal fluid was normal, with the exception of the presence of leucine-rich glioma-inactivated 1 (LGI1) antibodies, and LGI1 antibodies were also found in the blood serum. The presence of the antibodies, the faciobrachial dystonic seizures (FBDSs) and the memory loss indicated limbic encephalitis. After 3 months of immunotherapy, the patient was free from epileptic seizures and had undergone a partial memory restoration. FBDSs alone justify the immediate initiation of immunotherapy, even prior to laboratory confirmation of the disease, as early treatment limits the duration of the illness. [ABSTRACT FROM AUTHOR]

The dynamics of the ClO ClO (N2) radical complex (or chaperon) mechanism is studied by electronic structure methods and quasi-classical trajectory calculations. The geometries and frequencies of the stationary points on the potential energy surface (PES) are optimized at the B3LYP/6-311G(3df) level of theory, and the energies are refined at the CCSD(T)/6-311G(3df) (single-point) level of theory. Basis set superposition error (BSSE) corrections are applied to obtain 1.5 kcal mol-1for the binding energy of the ClO·N2van der Waals (VDW) complex. A model PES is developed and used in quasi-classical trajectory calculations to obtain the capture rate constant and nascent energy distributions of ClOOCl produced via the chaperon mechanism. A range of VDW binding energies from 1.5 to 9.0 kcal mol-1are investigated. The anisotropic PES for the ClO·N2complex and a separable anharmonic oscillator approximation are used to estimate the equilibrium constant for formation of the VDW complex. Rate constants, branching ratios to produce ClOOCl, and nascent energy distributions of excited ClOOCl are discussed with respect to the VDW binding energy and temperature. Interestingly, even for weak VDW binding energies, the N2usually carries away enough energy to stabilize the nascent ClOOCl, although the VDW equilibrium constant is small. For stronger binding energies, the stabilization efficiency is reduced, but the capture rate constant is increased commensurately. The resulting rate constants for forming ClOOCl from the title reaction are only weakly dependent on the VDW binding energy and temperature. As a result, the relative importance of the chaperon mechanism is mostly dependent on the VDW equilibrium constant. For the calculated ClO·N2binding energy of 1.5 kcal mol-1, the VDW equilibrium constant is small, and the chaperon mechanism is only important at very high pressures. [ABSTRACT FROM AUTHOR]