Neuroimaging in Pineal Tumors

BACKGROUND AND PURPOSE: The authors report radiological findings in 11 tumors in the pineal region, which were histologically diagnosed as germinomas, pineocytomas pineoblastomas, ependymomas, teratomas, and astrocytomas. METHODS: Computed tomography (CT) was performed in seven patients and magnetic resonance imaging (MRI) was performed in all patients. RESULTS: CT showed a solid or solid/cystic mass with variable contrast enhancement. MRI showed a heterogeneous mass, with hypointense signal on T1 and iso/hyperintense signal on T2-weighted images (WI) and gadolinium enhancement. Extension to adjacent structures occurred in five patients and spread through the cerebral spinal fluid (CSF) in two. CONCLUSIONS: Pineal region tumors have no pathognomonic imaging pattern. MRI and CT are complementary in diagnosis and are important to determine localization, extension, and meningeal spread.     

Effect of weightlessness on the development of the nervous system and peripheral analyzers inXenopus laevis larvae

The study was carried out within the framework of a Russian-Canadian experiment aboard the Bion-10 satellite. The volume and surface area of the gray and white matter and ventricles of the brain, retina, olfactory placodes, the VIII nerve ganglia, and vascular plexus were measured inXenopus laevis which had been in a state of weight-lessness for 2 weeks since their hatching. Zero gravity was found to stimulate the growth of nerve processes, to increase the surface of the vascular plexus, and to impede the development of the retina, olfactory placodes, and VIII nerve ganglia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 6, pp. 650–653, June, 1995 Presented by N. K. Permyakov, Member of the Russian Academy of Medical Sciences     

Interaction of sensory and cognitive processes during visual recognition: The role of the associative areas of the cerebral cortex

The first part of the present study used a model of Alzheimers disease in two groups of animals (three monkeys in each), given injections of neurotoxins (monkeys of group I) and physiological saline (monkeys of group II). Before injections, all monkeys were trained to discriminate stimuli containing different types of information (spatial frequency grids and geometrical figures of different colors and with different spatial relationships between objects) and to perform spatial selection. The dynamics of impairments in the characteristics of working memory were identified using delayed differentiation tasks in monkeys of both groups before injections and every two months after injections. Quantitative measures of impairments were made using the entropy of visual recognition, which characterizes uncertainty in decision-taking. The development of Alzheimers disease in rhesus macaques was characterized by a deficit of working memory, resulting from lesions to the two component processes of memory. Impairments of the first of these in monkeys of group I were manifest as a significant increase in entropy, which is associated with correct decision-taking. The magnitude of the increase depended on the type of visual information. Impairments of the second component were characterized by increases in entropy associated with refusals to take decisions and were independent of the delay duration and the type of visual information. Monkeys given injections of physiological saline showed no significant changes in these characteristics. The features of working memory were also studied in the second part of the investigation, using four groups of Rhesus macaques: intact, those with bilateral extirpation of the sulcus principalis or field 7 or both: degradation again identified two components. Entropy associated with this was increased significantly for most of the stimuli tested on monkeys of all extirpation groups as compared with intact animals. Significant differences were found in these characteristics for a number of stimuli, which depended on the location of the structures removed. The characteristics of impairments of the components of working memory resulting in the development of Alzheimers disease showed that the cholinergic mechanisms responsible for sensory processing differ from those involved in decision-taking. The structural-functional organization of the interaction of sensory and cognitive processes controlled by the motivation and attention systems is discussed, as is the role of the associative areas of the cortex.Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 89, No. 10, pp. 1226–1239, October, 2003.     

Synthetic peptide, a fragment of the β-subunit of chorionic gonadotropin, inhibits mitogen-stimulated proliferation of human lymphocytesin vitro

Similar to chorionic gonadotropin, synthetic fragment of the β-subunit of chorionic gonadotropin (128th–145th amino acid), inhibits mitogen-stimulated proliferation of human lymphocytesin vitro and binds to membrane receptors of human peripheral blood monocytes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 3, pp. 319–322, March, 1997     

Morphological analysis of the formation of cluster organization of neurons,forming the corticocortical connections in the cat visual cortex in early postnatal ontogenesis

The development of cluster organization of neurons forming direct interzonal associative projections from striate cortex (area 17) to extrastriate area 21a in cat was studied by a technique of horseradish peroxidase retrograde transport. Reconstruction of cortical region containing retrogradely labeled neurons was performed using continuous serial sections of the brain. The analysis of spatial organization was done and quantitative characteristics of distribution pattern of initial corticocortical neurons in striate cortex in kittens were obtained. Interzonal connections were detected since 14th postnatal day. Neuronal cluster organization started forming after day 21 while its pattern became similar to that in the adult animal both qualitatively and quantitatively by the end of the 2nd postnatal month, that is somewhat later than it was previously thought. The data obtained also demonstrate the age-dependent decrease in the convergence of the striate cortex projections to area 21a associated with the reduction of the area, occupied by initial neurons.     

Two methods of whole-genome amplification enable accurate genotyping across a 2320-SNP linkage panel

Comprehensive genome scans involving many thousands of SNP assays will require significant amounts of genomic DNA from each sample. We report two successful methods for amplifying whole-genomic DNA prior to SNP analysis, multiple displacement amplification, and OmniPlex technology. We determined the coverage of amplification by analyzing a SNP linkage marker set that contained 2320 SNP markers spread across the genome at an average distance of 2.5 cM. We observed a concordance of >99.8% in genotyping results from genomic DNA and amplified DNA, strongly indicating the ability of both methods used to amplify genomic DNA in a highly representative manner. Furthermore, we were able to achieve a SNP call rate of >98% in both genomic and amplified DNA. The combination of whole-genome amplification and comprehensive SNP linkage analysis offers new opportunities for genetic analysis in clinical trials, disease association studies, and archiving of DNA samples.