Cortical spreading depression confounds concentration-dependent pial arteriolar dilation during N-methyl-D-aspartate superfusion

Pial arterioles do not express N-methyl-D-aspartate (NMDA) receptors but dilate in response to topical NMDA application. We explored the mechanism underlying NMDA-mediated responses in murine pial arterioles (11-31 microm), using a closed cranial window preparation, and found that arteriolar dilation was not concentration dependent. Pial arteriolar diameter abruptly increased within 3 min of superfusing 50 or 100 microM NMDA. Dilation reached a peak within 1 min (46 +/- 14%) and then declined to a plateau (28 +/- 13%) for the duration of superfusion. Whereas a higher concentration (200 microM) did not produce further dilation, lower concentrations (1-10 microM) did not dilate the arterioles at all. MK-801 (10 microM) abrogated the dilation response, whereas Nomega-nitro-L-arginine (1 mM) attenuated the peak and abolished the sustained dilation during NMDA superfusion. We determined that NMDA-induced pial arteriolar responses were evoked by cortical spreading depression, because abrupt vasodilation during 50 or 100 microM NMDA superfusion was associated with a large negative slow potential shift and electrocorticogram suppression that spread from the superfusion window to distant cortical areas. Our data suggest that the responses of pial arterioles to NMDA are caused in part by neurovascular coupling due to cortical spreading depression.     

Helminths of roe deer (Capreolus capreolus) in the Middle Black Sea Region of Turkey

Fifteen roe deer were examined at necropsy from Northern Turkey in the period 2006-2010 for the helminth infections. Totally 6470 helminth specimens were collected and identified by morphological criteria. Twenty-five helminth species were identified (1 of the Class Trematoda, 1 of Cestoda and 23 of Nematoda). Dicrocoelium dendriticum (Prevalence 20%) was found in liver. Cysticercus tenuicollis (6.6%) was found in mesentery. Haemonchus contortus (53.3%), Ostertagia leptospicularis (73.3%), O. leptospicularis (minor morph: kolchida) (53.3%), Ostertagia ostertagi (26.6%), Spiculopteragia spiculoptera (66.6%), S. spiculoptera (minor morph: mathevossiani) (6.6%), Teladorsagia circumcincta (40.0%), T. circumcincta (minor morph: davtiani) (6.6%), T. circumcincta (minor morph: trifurcata) (6.6%), Trichostrongylus axei (66.6%) were found in abomasum. Trichostrongylus andreevi (6.6%), T. colubriformis (6.6%), T. longispicularis (26.6%), T. vitrinus (40.0%), T. capricola (6.6%), Cooperia oncophora (26.6%), C. punctata (6.6%), Nematodirus filicollis (66.6%), and Capillaria bovis (26.6%) were found in small intestine. Oesophagostomum venulosum (46.6%), Chabertia ovina (26.6%), and Trichuris ovis (13.3%) were found in large intestine. Dictyocaulus capreolus (6.6%) was found in lungs.     

Antioxidant status in cerebrovascular accident

Ischemia is associated with the pathological changes caused by the accumulation of reactive oxygen metabolites (ROM) in cerebrovascular accident (CVA). The aim of this study was to determine red cell copper/zinc-superoxide dismutase (Cu/Zn-SOD) and catalase activities and copper and zinc concentrations both in plasma and in red cells in CVA. Cu/Zn-SOD and catalase activities of 16 patients, with an average age of 64 yr, were measured spectrophotometrically; copper and zinc concentrations were determined by atomic absorption spectrophotometer. The results showed that Cu/Zn-SOD activity was increased markedly in patients compared to the young controls and reached a peak on the d 5 of the disease, whereas the catalase activity of the patients on d 3 and d 5 were in the normal range, but higher on d 10. The enzyme activities of the elderly group were generally increased compared to the young controls. Copper and zinc concentrations showed corresponding alterations. These findings suggested that the effects of oxidative stress in CVA might be reflected in red cell and plasma parameters. Presented at the III International Congress of Pathophysiology, Lahti, Finland, 28 June–3 July, 1998.     

Biomolecular network motif counting and discovery by color coding

Protein-protein interaction (PPI) networks of many organisms share global topological features such as degree distribution, k-hop reachability, betweenness and closeness. Yet, some of these networks can differ significantly from the others in terms of local structures: e.g. the number of specific network motifs can vary significantly among PPI networks. Counting the number of network motifs provides a major challenge to compare biomolecular networks. Recently developed algorithms have been able to count the number of induced occurrences of subgraphs with k < or = 7 vertices. Yet no practical algorithm exists for counting non-induced occurrences, or counting subgraphs with k > or = 8 vertices. Counting non-induced occurrences of network motifs is not only challenging but also quite desirable as available PPI networks include several false interactions and miss many others. In this article, we show how to apply the 'color coding' technique for counting non-induced occurrences of subgraph topologies in the form of trees and bounded treewidth subgraphs. Our algorithm can count all occurrences of motif G' with k vertices in a network G with n vertices in time polynomial with n, provided k = O(log n). We use our algorithm to obtain 'treelet' distributions for k < or = 10 of available PPI networks of unicellular organisms (Saccharomyces cerevisiae Escherichia coli and Helicobacter Pyloris), which are all quite similar, and a multicellular organism (Caenorhabditis elegans) which is significantly different. Furthermore, the treelet distribution of the unicellular organisms are similar to that obtained by the 'duplication model' but are quite different from that of the 'preferential attachment model'. The treelet distribution is robust w.r.t. sparsification with bait/edge coverage of 70% but differences can be observed when bait/edge coverage drops to 50%.     

Optimal pooling for genome re-sequencing with ultra-high-throughput short-read technologies

New generation sequencing technologies offer unique opportunities and challenges for re-sequencing studies. In this article, we focus on re-sequencing experiments using the Solexa technology, based on bacterial artificial chromosome (BAC) clones, and address an experimental design problem. In these specific experiments, approximate coordinates of the BACs on a reference genome are known, and fine-scale differences between the BAC sequences and the reference are of interest. The high-throughput characteristics of the sequencing technology makes it possible to multiplex BAC sequencing experiments by pooling BACs for a cost-effective operation. However, the way BACs are pooled in such re-sequencing experiments has an effect on the downstream analysis of the generated data, mostly due to subsequences common to multiple BACs. The experimental design strategy we develop in this article offers combinatorial solutions based on approximation algorithms for the well-known max n-cut problem and the related max n-section problem on hypergraphs. Our algorithms, when applied to a number of sample cases give more than a 2-fold performance improvement over random partitioning.