Millimeter-scale resolution of trace metal distributions in microbial mats from a hypersaline environment in Baja California, Mexico.

Microbial mats from two ponds with different salinities from the saltern of Guerrero Negro (Mexico) points toward millimeter-scale coherent variations in trace metal (Me) concentrations (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn). Total, HCl-leachable and pyrite-associated Me showed a trend of increasing concentrations with increasing depth suggesting gradual addition of reactive Me probably as a result of metal sulfide precipitation at depth. The trends in Me profiles can be ascribed to the establishment and maintenance of microzones that promote geochemical processes, bacterial population distributions, and differential mass transport within the mats. Degrees of trace metal pyritization (1 ± 1% for Zn to 24 ± 7% for Cd) as well as metals associated with the pyrite fraction (<1.4-36 ± 18 nmol g(-1) for Zn and Mn, respectively) were low, as expected from a reactive Fe-limited system like Guerrero Negro. Calculated enrichment factors showed that Ni (2.6 ± 2.1), Co (5.5 ± 4.0), Pb (9.4 ± 7.4), and Cd (57 ± 39) were, on average, enriched in the microbial mats of Guerrero Negro. Natural enrichments of Cd, Pb, and Co in sediments along the coast of Baja California and metabolical requirements of Co and Ni by the predominant cyanobacteria in the Guerrero Negro mats may explain these enrichments. Metal characteristics in microbial mats could be advantageously used as biosignatures to identify their presence in the geological record or in other planetary systems.

Relationship between metal enrichments and a biological adverse effects index in sediments from Todos Santos Bay, northwest coast of Baja California, México.

In 1992 and 2004, heavy metals concentrations were measured in surficial sediments from Todos Santos Bay, located in Ensenada, Baja California, Mexico. The aim was to search for relationships between metal enrichment factors and a biological adverse effects index. Unlike Ni, the elements Cd, Cu and Zn showed significant correlations (p<0.05) between enrichment factors and the biological adverse effects index. Cu showed a 0.74:1 relationship, which means that any enrichment above 0.74 could represent biological adverse effects. On the other hand, Cd and Zn enrichments must be >5.5 and >1.5, respectively, in order for the sediments to be considered toxic. In general, data showed that most of the metal concentrations in Todos Santos Bay sediments could not cause adverse effects to biota. Only Ensenada's harbor and the zone next to a dredging dumping site showed metal enrichments that could be toxic.

Symptom onset of spinocerebellar ataxia type 10 in pregnancy and puerperium.

Spinocerebellar ataxia type 10 is an autosomal dominant neurodegenerative disorder. It was initially described in Mexican families presenting with ataxia and epilepsy, with or without polyneuropathy, pyramidal signs and cognitive symptoms. The authors report three patients from the same family who were asymptomatic until gestation and puerperium, when they developed symptoms and signs suggestive of the syndrome. Genetic diagnosis was made in the three patients. The authors hypothesize that hormonal changes are likely to influence the manifestation of the condition.

Distribution of mercury in surficial sediments from Todos Santos Bay, Baja California, México.

During 2004 the spatial distribution of total Hg in sediments from Todos Santos Bay, Baja California, México was studied to evaluate the degree of environmental impact in this bay. The results showed low concentrations and no Hg enrichment at any site. These findings suggest natural levels of Hg in the water of Todos Santos Bay. The regional distribution of Hg/Fe shows lower values in the East and higher in the West of the bay. No significant correlations (p<0.05) were found between Hg and organic matter or particle size, suggesting that the distribution of Hg is not controlled by these variables.

Generalized dystonia and striatal calcifications with lipoid proteinosis.

Lipoid proteinosis (LP) is an autosomal recessive disease that typically presents with papular, verrucous, poxlike, or acneiform scars and lesions and hoarseness. LP was recently mapped to the 1q21 locus and shown to result from mutations in the extracellular matrix protein 1 gene (ECM1). Epilepsy, mental retardation, and hippocampal calcifications can occur. The authors describe a patient with generalized dystonia caused by striatal calcifications.

[Acute cerebellitis caused by Epstein-Barr virus: case report]. / Cerebelite aguda causada por vírus Epstein-Barr: relato de caso.

Acute cerebellitis can occur in association with varicella-zoster virus, enterovirus, mumps, mycoplasma, and other infective organisms. Acute cerebellitis is a rare complication of Epstein-Barr virus (EBV) infection. We report the case of a 21-year-old woman with a 12-day history of nausea and vomiting, gait and limbs ataxia, myoclonus, tremor of head and all four limbs, opsoclonus and cutaneous rash. Anti-EBV IgG and IgM antibodies against antiviral capsid were positive and anti-EBV against virus-associated nuclear antigen was also positive. EBV infection in association with neurological findings can occur without the classic signs and symptoms of infectious mononucleosis.

[Contributions of Charcot and Marsden to the development of movement disorders in the 19th and 20th centuries]. / As contribuições de Charcot e de Marsden para o desenvolvimento dos distúrbios do movimento nos séculos XIX e XX.

Charcot described many neurological diseases in the 19th century, particularly in movement disorders. Charcot contributed in the clinical description of Parkinson's disease, and introduced its first pharmacological treatment. He also studied the hyperkinesias, e.g. of Tourette syndrome, differential diagnosis of tremors, dystonias, choreas and startle disease. Marsden, who died recently, was an exponent in the study of Movement Disorders, with many publications in this field in the 20th century. His most important contributions are definitions and classifications of movement disorders, such as Parkinson's disease, dystonia, myoclonus, essential tremor, the description of the syndromes "Painful Legs Moving Toes", "Gait Ignition Failure" and "Primary Writing Tremor". The contributions of Charcot in the 19th century and Marsden in the 20th century to the movement disorders allow us to conclude that both of them were the most representative icons in this field in the past two centuries.