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Background: The vascular deposition of amyloid known as cerebral amyloid angiopathy (CAA) – an age-associated condition and a common finding in Alzheimer’s disease – compromises cerebral blood flow, causing macro/microhemorrhages and/or cognitive impairment. Very little is known about the mechanisms causing CAA-related degeneration of cerebral vascular cells. The Dutch E22Q familial amyloid-β (Aβ) variant is primarily associated with CAA, and manifests clinically with severe cerebral hemorrhages. Objective: We aimed to determine the molecular mechanisms causing apoptosis of cerebral endothelial cells in the presence of wild-type Aβ40 or its vasculotropic E22Q variant. Methods: We challenged human brain microvascular endothelial cells with both Aβ variants, and studied the apoptotic pathways triggered by these peptides. Results: Caspase-mediated apoptotic pathways were elicited by both peptides within time frames correlating with their aggregation properties and formation of oligomeric/protofibrillar assemblies. Our data revealed a primary activation of caspase-8 (typically triggered by death receptors) with secondary engagement of caspase-9, with cytochrome C and apoptosis-inducing factor release from the mitochondria, suggesting the independent or synergistic engagement of extrinsic and intrinsic apoptotic mechanisms. Conclusion: Our data demonstrate the induction of caspase-8- and caspase-9-dependent mitochondrial-mediated apoptotic pathways by Aβ oligomers/protofibrils in vascular cells, likely implicating a primary activation of death receptors.

Objective: To determine whether the well-established filter paper spotted blood method used for the determination of some amino acids could be reliably used to measure all amino acids and whether amino acid results thus obtained are reproducible and comparable to the results obtained by measuring plasma amino acids in either capillary or venous blood. Methods :This is a prospective study in which blood samples from a finger-prick were collected in capillary tubes and at the same time blotted on filter papers; another sample was taken from a vein, from 19 healthy volunteers aged between 18 and 24 yr after a strict 12-h overnight fast. Another 9 healthy adult volunteers provided blood samples on filter papers for the storage study; 9 samples were analyzed immediately; 9, 8 and 4 samples were stored at −20°C, −4°C and room temperature respectively and analyzed after 14 days; 8 samples stored at −20°C were analyzed after 4 weeks. Results : Intra-sample reproducibility in the filter paper blood from the same individual was found to be mostly less than 20%, while for the capillary blood was less than 5%. The greatest variability was in cystine and methionine. There was no significant difference between results obtained from capillary blood and from venous blood, but there was a significant difference between amino acid concentrations in venous and capillary blood on the one hand and filter paper blood on the other. Storage at different temperatures and for a varied period of time showed little change except in serine, glutamate, ornithine, histidine, cystine and methionine. There was a 30% decrease in concentrations of most amino acids in filter paper blood when compared to capillary or venous blood probably because of loss in the extraction process. Conclusion: A new set of values for amino acids in filter paper blood in normal individuals is presented. Blood spotted filter paper could be used to screen practically all inborn errors of amino acid metabolism.

Here we show for the first time that components of pulp and paper mill effluents contain neuroactive substances that may impair fish reproduction. Grab samples of primary and secondary effluent were obtained from a representative pulp and paper mill in Eastern Canada. Effluents were fractionated using classic polarity and polyphenolic extraction methods into solvents of selected polarities (water, ethanol, ethyl acetate, and hexane). By means of in vitro, competitive assays on goldfish (Carassius auratus) brain tissues, the extracts were screened for their ability to interact with enzymes and receptors involved in gamma-aminobutyric acid (GABA), dopamine, glutamate, and acetylcholine-dependent neurotransmission. These neurotransmission pathways have essential regulatory roles in fish reproduction. Radioligand binding to the following neurotransmitter receptors were significantly impacted following in vitro incubations with extracts (percentage change from controls indicated in brackets): dopamine-2 (D2; 21-48% increase), GABA(A) receptor binding (65-67% decrease and 189% increase), N-methyl-o-aspartic acid (NMDA; 26-75% decrease), and muscarinic cholinergic (mACh; 42% increase). Activities of the following neurotransmitter-related enzymeswere significantly impacted: monoamine oxidase (MAO; 14-48% decrease), GABA-transaminase activity (33% decrease and 21-69% increase), and acetylcholinesterase (AChE; 21-50% decrease). No changes in glutamic acid decarboxylase (GAD) activity were detected. These findings provide a novel and plausible mechanism by which pulp and paper mills effluents impair fish reproduction by interacting with neurotransmitter systems. Furtherwork is required to identify the active compounds and explore whether these changes occur in vivo.

Objective: Abnormal thalamo-cortical oscillations underlie idiopathic generalised epilepsy (IGE). Although thalamic involvement has long been indicated by electrophysiological data, it has only recently become feasible to test this with independent methods. In this magnetic resonance (MR) study, we investigated the metabolic and structural integrity of the thalamus. Possible changes in glutamine and glutamate concentrations and signs of neuronal damage were of particular interest. Method: Forty three IGE patients and 38 age and sex matched healthy controls were investigated. Quantitative single volume MR spectroscopy (MRS, 1.5 T) was used to measure concentrations of glutamate and glutamine (Glx) and N -acetyl aspartate (NAA) in thalamus and occipital cortex. We also measured thalamic volumes on high resolution gradient-echo images and estimated fractions of thalamic grey and white matter with voxel based morphometry (VBM). Results: IGE patients showed elevated Glx and reduced NAA concentrations in the thalamus compared to controls (12.2±2.6 v 8.9±4.1 mM, p = 0.0022 for Glx, and 9.9±1.0 v 10.7±0.9 mM, p = 0.017 for NAA). Thalamic grey matter fraction was reduced in IGE patients, and white matter fraction was increased with the greatest increase in the dorso-medial thalamus. Mean thalamic volume was reduced in patients (6.7±0.7 v 7.2±0.6 ml in controls, p = 0.0001), as was mean cerebral volume (1163±128 v 1250±102 ml, p = 0.0003). Patients’ thalamus/whole brain ratios were normal. Conclusion: Quantitative MRS and VBM provide further evidence for involvement of the thalamus in IGE. The observed elevation of Glx levels together with reductions in NAA levels and grey matter fractions are consistent with epilepsy related excitoxicity as a possible underlying mechanism.

Background: Primary progressive multiple sclerosis (PP-MS) differs from relapsing-remitting or secondary progressive MS (RR/SP-MS) in ways suggesting differences in the pathogenic pathways. Susceptibility to both PP-MS and RR/SP-MS is linked to carriage of the HLA molecule DRB1*1501. Several serologically defined HLA-DR groups (DR1, DR4, DR6, and DR9) occur less often in RR/SP-MS than in controls. Some or all of the HLA-DR molecules encoded by alleles in these serologically defined groups have a negatively charged glutamic acid at residue 71 or 74 of the beta 1 chain (beta 171 / beta 174). Residues at these positions are important in the formation of pocket 4 in the antigen binding site of the HLA-DR molecule. Objectives: To investigate whether the presence of alleles encoding HLA-DR molecules containing glutamic acid at beta 171 / beta 174 correlates with the course of MS. Methods: HLA-DR and HLA-DQ alleles and genotypes were analysed in 121 MS patients (50 with PP-MS) and 109 controls by molecular typing. Results: Alleles encoding HLA-DR molecules containing a glutamic acid at beta 171 / beta 174 occurred less often in patients with RR/SP-MS than in those with PP-MS or controls. In subjects not carrying the DRB1*1501 allele, a much higher proportion of PP-MS patients carried alleles encoding HLA-DR molecules containing a glutamic acid at beta 171 / beta 174 than did RR/SP-MS patients or controls. Conclusions: The amino acid residues involved in determining the shape and charge of pocket 4 of the HLA-DR beta 1 chain could influence the clinical course of MS by determining protection against RR/SP-MS or susceptibility to the development of PP-MS.

During a search for hemoglobin variants in Manitoba, two unrelated patients were found who appear to possess the trait for hemoglobin E Saskatoon (β22 Glu → Lys) on the basis of peptide map analyses of the variant fractions.