Pseudotumoral Demyelinating Lesions: A Presentation of Acute Disseminated Encephalomyelitis.

Pseudotumoral forms of demyelination are related to central nervous system demyelinating disorders, usually considered to be an atypical presentation of multiple sclerosis including its different varieties such as Balo's, Schilder's, and Marburg diseases. These lesions could also be seen in myelin oligodendrocyte glycoprotein antibody-associated demyelination, acute disseminated encephalomyelitis (ADEM), and neuromyelitis optica spectrum disorder. The pseudotumoral aspect may be mistakenly considered as an abscess or a cancerous tumor, in which case, patients could endure unnecessary possibly harmful brain biopsy and have a delay in their disease diagnostics and management. Once latter differential diagnosis is discarded, pseudotumoral demyelination prompts uncertainties concerning the nature of the underlying demyelinating condition as prognosis and management differ from multiple sclerosis to other syndromes, especially whether a chronic treatment is needed or not. In this case report, we present a 35-year-old male patient hospitalized in the department of neurology for a rapidly progressive onset of encephalopathy and polyfocal neurological deficits, with pseudotumoral lesions shown on brain MRI. On further investigations, ADEM was the more likely diagnosis that could fit the patient's clinical and radiological presentation. Thence, he was put on high dose of intravenous corticosteroids, with a followed good recovery within the first week of the treatment.

Oxidative stress and DNA damage in obesity-related tumorigenesis.

Reactive oxygen species induce oxidative modification of critical macromolecules. Oxygen derived free radicals may act as potential cytotoxic intermediates inducing inflammatory and degenerative processes, or as signal messengers for the regulation of gene expression. This dual effect mainly depends on the availability of free radicals in terms of concentration, as well as on the environmental characteristics in which they are produced. The formation of free radicals has been proposed to be the linking factor between certain metabolic disturbances and cancer. Circulating mononuclear cells of patients with high cholesterol levels, insulin resistance, metabolic syndrome or obesity present lower levels of antioxidant enzymes and increased concentrations of oxidative stress by-products such as isoprostanes or the DNA oxidized and highly mutagenic base 8-oxo-7,8-dihydro-2'-deoxyguanosine. Overweight or obese subjects also exhibit hormonal changes as a consequence of the increase of mass fat, and these hormonal alterations have been implicated in the alteration of different signal transduction mechanisms and in cell growth and differentiation. A significant correlation has been found between body mass index and cancer. The biological factors and molecular mechanisms implicated in obesity associated cancer susceptibility will be reviewed.

Oxidative DNA cleavage induced by an iron(III) flavonoid complex: synthesis, crystal structure and characterization of chlorobis(flavonolato)(methanol) iron(III) complex.

A flavonol iron(III) complex, [Fe(flavonolato)(2)Cl(MeOH)], has been prepared. The compound has been characterized by X-ray crystallography, spectroscopy, magnetism and electronic paramagnetic resonance (EPR) at X- and Q-band. The geometrical environment around the metal is best described as rhombic distorted octahedral. This distortion has also been inferred from the magnetic measurements and from the EPR spectra at different temperatures, E/D(rhombicity parameter) approximately 0.06. The DNA cleavage activity of the iron(III) complex with and without ascorbate/hydrogen peroxide is reported. Mechanisms of the oxidative cleavage have been proposed when DNA strand scission is performed both with and without ascorbate/hydrogen peroxide activation.