Detection of dimethyl sulfone in the human brain by in vivo proton magnetic resonance spectroscopy

We wish to report the detection of dimethyl sulfone (methylsulfonylmethane, C2H6O2S) in the brain of a normal 62-year-old male using in vivo proton magnetic resonance spectroscopy. The presence of this exogenous metabolite resulted from ingestion of a dietary supplement containing dimethyl sulfone. The concentration of this compound in the brain was measured to be 2.4 mmol, with a washout half life of approximately 7.5 days. The in vivo T-1 and T-2 relaxation times of dimethyl sulfone were measured to be 2180 ms and 385 ms, respectively. The concentration of major brain metabolites, namely N-acetylaspartate, total Creatine and Choline, and myo-Inositol were within normal limits. (C) 2000 Elsevier Science Inc. All rights reserved.

White matter microstructure underlying default mode network connectivity in the human brain

Resting state functional magnetic resonance imaging (fMRI) reveals a distinct network of correlated brain function representing a default mode state of the human brain The underlying structural basis of this functional connectivity pattern is still widely unexplored We combined fractional anisotropy measures of fiber tract integrity derived from diffusion tensor imaging (DTI) and resting state fMRI data obtained at 3 Tesla from 20 healthy elderly subjects (56 to 83 years of age) to determine white matter microstructure e 7 underlying default mode connectivity We hypothesized that the functional connectivity between the posterior cingulate and hippocampus from resting state fMRI data Would be associated with the white matter microstructure in the cingulate bundle and fiber tracts connecting posterior cingulate gyrus With lateral temporal lobes, medial temporal lobes, and precuneus This was demonstrated at the p<0001 level using a voxel-based multivariate analysis of covariance (MANCOVA) approach In addition, we used a data-driven technique of joint independent component analysis (ICA) that uncovers spatial pattern that are linked across modalities. It revealed a pattern of white matter tracts including cingulate bundle and associated fiber tracts resembling the findings from the hypothesis-driven analysis and was linked to the pattern of default mode network (DMN) connectivity in the resting state fMRI data Out findings support the notion that the functional connectivity between the posterior cingulate and hippocampus and the functional connectivity across the entire DMN is based oil distinct pattern of anatomical connectivity within the cerebral white matter (C) 2009 Elsevier Inc All rights reserved

Equal Numbers of Neuronal and Nonneuronal Cells Make the Human Brain an Isometrically Scaled-Up Primate Brain

The human brain is often considered to be the most cognitively capable among mammalian brains and to be much larger than expected for a mammal of our body size. Although the number of neurons is generally assumed to be a determinant of computational power, and despite the widespread quotes that the human brain contains 100 billion neurons and ten times more glial cells, the absolute number of neurons and glial cells in the human brain remains unknown. Here we determine these numbers by using the isotropic fractionator and compare them with the expected values for a human-sized primate. We find that the adult male human brain contains on average 86.1 +/- 8.1 billion NeuN-positive cells (""neurons"") and 84.6 +/- 9.8 billion NeuN-negative (""nonneuronal"") cells. With only 19% of all neurons located in the cerebral cortex, greater cortical size (representing 82% of total brain mass) in humans compared with other primates does not reflect an increased relative number of cortical neurons. The ratios between glial cells and neurons in the human brain structures are similar to those found in other primates, and their numbers of cells match those expected for a primate of human proportions. These findings challenge the common view that humans stand out from other primates in their brain composition and indicate that, with regard to numbers of neuronal and nonneuronal cells, the human brain is an isometrically scaled-up primate brain. J. Comp. Neurol. 513:532-541, 2009. (c) 2009 Wiley-Liss, Inc.

Determination of trace elements in human brain tissues using neutron activation analysis

Neutron activation analysis was applied to assess trace element concentrations in brain tissues from normal (n = 21) and demented individuals (n = 21) of both genders aged more than 50 years. Concentrations of the elements Br, Fe, K, Na, Rb, Se and Zn were determined. Comparisons were made between the results obtained for the hippocampus and frontal cortex tissues, as well as, those obtained in brains of normal and demented individuals. Certified reference materials, NIST 1566b Oyster Tissue and NIST 1577b Bovine Liver were analyzed for quality of the analytical results.

The ""single-section"" Golgi method adapted for formalin-fixed human brain and light microscopy

The Golgi method has been used for over a century to describe the general morphology of neurons in the nervous system of different species. The ""single-section"" Golgi method of Gabbott and Somogyi (1984) and the modifications made by Izzo et al. (1987) are able to produce consistent results. Here, we describe procedures to show cortical and subcortical neurons of human brains immersed in formalin for months or even years. The tissue was sliced with a vibratome, post-fixed in a combination of paraformaldehyde and picric acid in phosphate buffer, followed by osmium tetroxide and potassium dicromate, ""sandwiched"" between cover slips, and immersed in silver nitrate. The whole procedure takes between 5 and 11 days to achieve good results. The Golgi method has its characteristic pitfalls but, with this procedure, neurons and glia appear well-impregnated, allowing qualitative and quantitative studies under light microscopy. This contribution adds to the basic techniques for the study of human nervous tissue with the same advantages described for the ""single-section"" Golgi method in other species; it is easy and fast, requires minimal equipment, and provides consistent results. (C) 2010 Elsevier B.V. All rights reserved.

Opposite Effects of Delta-9-Tetrahydrocannabinol and Cannabidiol on Human Brain Function and Psychopathology

Delta-9-tetrahydrocannabinol (Delta-9-THC) and Cannabidiol (CBD), the two main ingredients of the Cannabis sativa plant have distinct symptomatic and behavioral effects. We used functional magnetic resonance imaging (fMRI) in healthy volunteers to examine whether Delta-9-THC and CBD had opposite effects on regional brain function. We then assessed whether pretreatment with CBD can prevent the acute psychotic symptoms induced by Delta-9-THC. Fifteen healthy men with minimal earlier exposure to cannabis were scanned while performing a verbal memory task, a response inhibition task, a sensory processing task, and when viewing fearful faces. Subjects were scanned on three occasions, each preceded by oral administration of Delta-9-THC, CBD, or placebo. BOLD responses were measured using fMRI. In a second experiment, six healthy volunteers were administered Delta-9-THC intravenously on two occasions, after placebo or CBD pretreatment to examine whether CBD could block the psychotic symptoms induced by Delta-9-THC. Delta-9-THC and CBD had opposite effects on activation relative to placebo in the striatum during verbal recall, in the hippocampus during the response inhibition task, in the amygdala when subjects viewed fearful faces, in the superior temporal cortex when subjects listened to speech, and in the occipital cortex during visual processing. In the second experiment, pretreatment with CBD prevented the acute induction of psychotic symptoms by Delta-9-tetrahydrocannabinol. Delta-9-THC and CBD can have opposite effects on regional brain function, which may underlie their different symptomatic and behavioral effects, and CBD`s ability to block the psychotogenic effects of Delta-9-THC. Neuropsychopharmacology (2010) 35, 764-774; doi:10.1038/npp.2009.184; published online 18 November 2009

Eag1 potassium channel immunohistochemistry in the CNS of adult rat and selected regions of human brain

Eag1 (K(v)10.1) is the founding member of an evolutionarily conserved superfamily of voltage-gated K+ channels. In rats and humans Eag1 is preferentially expressed in adult brain but its regional distribution has only been studied at mRNA level and only in the rat at high resolution. The main aim of the present study is to describe the distribution of Eag1 protein in adult rat brain in comparison to selected regions of the human adult brain. The distribution of Eag1 protein was assessed using alkaline-phosphatase based immunohistochemistry. Eag1 immunoreactivity was widespread, although selective, throughout rat brain, especially noticeable in the perinuclear space of cells and proximal regions of the extensions, both in rat and human brain. To relate the results to the relative abundance of Eag1 transcripts in different regions of rat brain a reverse-transcription coupled to quantitative polymerase chain reaction (real time PCR) was performed. This real time PCR analysis showed high Eag1 expression in the olfactory bulb, cerebral cortex, hippocampus, hypothalamus, and cerebellum. The results indicate that Eag1 protein expression greatly overlaps with mRNA distribution in rats and humans. The physiological relevance of potassium channels in the different regions expressing Eag1 protein is discussed. (C) 2008 IBRO. Published by Elsevier Ltd. All rights reserved.

Quantitation of alternatively spliced NMDA receptor NR1 isoform mRNA transcripts in human brain by competitive RT-PCR

The N-methyl-D-aspartate (NMDA)-selective subtype of ionotropic glutamate receptor is of importance in neuronal differentiation and synapse consolidation, activity-dependent forms of synaptic plasticity, and excitatory amino acid-mediated neuronal toxicity [Neurosci. Res. Program, Bull. 19 (1981) 1; Lab. Invest. 68 (1993) 372]. NMDA receptors exist in vivo as tetrameric or pentameric complexes comprising proteins from two families of homologous subunits, designated NR1 and NR2(A-D) [Biochem. Biophys. Res. Commun. 185 (1992) 826]. The gene coding for the human NR1 subunit (hNR1) is composed of 21 exons, three of which (4, 20 and 21) can be differentially spliced to generate a total of eight distinct subunit variants. We detail here a competitive RT-PCR (cRT-PCR) protocol to quantify endogenous levels of hNR1 splice variants in autopsied human brain. Quantitation of each hNR1 splice variant is performed using standard curve methodology in which a known amount of synthetic ribonucleic acid competitor (internal standard) is co-amplified against total RNA. This method can be used for the quantitation of hNR1 mRNA levels in response to acute or chronic disease states, in particular in the glutamatergic-associated neuronal loss observed in Alzheimer's disease [J. Neurochem. 78 (2001) 175]. Furthermore, alterations in hNR1 mRNA expression may be reflected at the translational level, resulting in functional changes in the NMDA receptor. (C) 2003 Elsevier Science B.V. All rights reserved.

Quantitation of human brain GABAA receptor isoforms by competitive RT-PCR

We have developed a competitive RT-PCR assay, adapted from Lewohl et al. [Brain Res. Brain Res. Protoc. 1 (1997) 347]. for the quantitation of GABA, receptor beta isoforms in human brain using an internal standard that shares high sequence homology to the targets. The internal standard is identical to the beta(1) sequence except for a 61 bp deletion and the incorporation of a Hind III restriction enzyme site. Unlike traditional competitive RT-PCR, which requires a range of internal standard concentrations to be titrated against a constant amount of unknown, this method relies on a standard curve for quantitation of each sample and thus permits increased sample throughput. This method is suitable for the quantitation of beta(1), beta(2) and beta(3) isoforms of the GABA(A) receptor in human alcoholic and control brain. (C) 2003 Elsevier Science B.V. All rights reserved.

Expression of hNP22 is altered in the frontal cortex and hippocampus of the alcoholic human brain

Background: Human neuronal protein (hNP22) is a gene with elevated messenger RNA expression in the prefrontal cortex of the human alcoholic brain. hNP22 has high homology with a rat protein (rNP22). These proteins also share homology with a number of cytoskeleton-interacting proteins. Methods: A rabbit polyclonal antibody to an 18-amino acid epitope was produced for use in Western and immunohistochemical analysis. Samples from the human frontal and motor cortices were used for Western blots (n = 10), whereas a different group of frontal cortex and hippocampal samples were obtained for immunohistochemistry (n = 12). Results: The hNP22 antibody detected a single protein in both rat and human brain. Western blots revealed a significant increase in hNP22 protein levels in the frontal cortex but not the motor cortex of alcoholic cases. Immunohistochemical studies confirmed the increased hNP22 protein expression in all cortical layers. This is consistent with results previously obtained using Northern analysis. Immunohistochemical analysis also revealed a significant increase of hNP22 immunoreactivity in the CA3 and CA4 but not other regions of the hippocampus. Conclusions: It is possible that this protein may play a role in the morphological or plastic changes observed after chronic alcohol exposure and withdrawal, either as a cytoskeleton-interacting protein or as a signaling molecule.

UNCERTAINTY AND DECISION-MAKING IN THE HUMAN BRAIN

Dissertation presented to obtain the Ph.D degree in Biology, Neuroscience

The bounds of education in the human brain connectome

Inter-individual heterogeneity is evident in aging; education level is known to contribute for this heterogeneity. Using a cross-sectional study design and network inference applied to resting-state fMRI data, we show that aging was associated with decreased functional connectivity in a large cortical network. On the other hand, education level, as measured by years of formal education, produced an opposite effect on the long-term. These results demonstrate the increased brain efficiency in individuals with higher education level that may mitigate the impact of age on brain functional connectivity.

Synthesis and biological evaluation of mono and bis-naphthalimide derivatives against SH-SY5Y, human brain cancer cells

Dissertação de mestrado em Medicinal Chemistry