An innexin-dependent cell network establishes left-right neuronal asymmetry in C. elegans

Gap junctions are widespread in immature neuronal circuits, but their functional significance is poorly understood. We show here that a transient network formed by the innexin gap-junction protein NSY-5 coordinates left-right asymmetry in the developing nervous system of Caenorhabditis elegans. nsy-5 is required for the left and right AWC olfactory neurons to establish stochastic, asymmetric patterns of gene expression during embryogenesis. nsy-5-dependent gap junctions in the embryo transiently connect the AWC cell bodies with those of numerous other neurons. Both AWCs and several other classes of nsy-5-expressing neurons participate in signaling that coordinates left-right AWC asymmetry. The right AWC can respond to nsy-5 directly, but the left AWC requires nsy-5 function in multiple cells of the network. NSY-5 forms hemichannels and intercellular gap-junction channels in Xenopus oocytes, consistent with a combination of cell-intrinsic and network functions. These results provide insight into gap-junction activity in developing circuits.     

Therapeutic potential of Smilax fluminensis ethanolic extract: antitumoral activity in murine melanoma cells

The aim of the study was to investigate the in vitro and in vivo antitumor activity of leaves ethanol extract from Smilax fluminensis on murine melanoma. The extract was performed by ethylic alcohol and submitted to classical chemical analysis. Cytotoxicity test were performed on neoplastic cells, where antitumor activity was expressed in GI₅₀ (concentration that inhibits 50% of cell growth) and the determination of selectivity index using a normal cell line. In addition, BALB/c mice models were used to evaluate the in vivo antitumor activity of extract in two different concentrations against B16-F10 melanoma cells. The tumor inhibition ratio was determined and the histopathological analyses of nodules and liver were compared. The chemical analysis indicated a major presence of phenolic compounds and flavonoids. Cytotoxicity test results that S. fluminensis extract was active in B16-F10 line (GI₅₀: 4.37 µg/mL), being the extract considered a promising antineoplastic agent. In the experimental model, the inhibition percentage of tumoral growth was between 78.77 and 83.49%. Histopathology analysis of nodules showed necrotic cells reduction, adipocytes presence, melanin deposition, vascularization, and inflammatory process in a concentration-dependent manner. On the liver, the animals treated with the extract on both concentrations showed normal hepatic organization, normal hepatocytes, and absence of inflammatory focus. The results indicate that S. fluminensis extract demonstrated both in vitro and in vivo antitumor activity, reducing the tumoral growth in B16-F10 and could therefore be a promising antineoplastic agent.

     

Highwire regulates synaptic growth in Drosophila

The formation, stabilization, and growth of synaptic connections are dynamic and highly regulated processes. The glutamatergic neuromuscular junction (NMJ) in Drosophila grows new boutons and branches throughout larval development. A primary walking behavior screen followed by a secondary anatomical screen led to the identification of the highwire (hiw) gene. In hiw mutants, the specificity of motor axon pathfinding and synapse formation appears normal. However, NMJ synapses grow exuberantly and are greatly expanded in both the number of boutons and the extent and length of branches. These synapses appear normal ultrastructurally but have reduced quantal content physiologically. hiw encodes a large protein found at presynaptic terminals. Within presynaptic terminals, HIW is localized to the periactive zone surrounding active zones; Fasciclin II (Fas II), which also controls synaptic growth, is found at the same location.     

Benzimidazole-2-carboxamides as novel NR2B selective NMDA receptor antagonists

A novel series of benzimidazole-2-carboxamide derivatives was prepared and identified as NR2B selective NMDA receptor antagonists. The influence of some structural elements, like H-bond donor groups placed on the benzimidazole skeleton and the substitution pattern of the piperidine ring, on the biological activity was studied. Compound 6a showed excellent analgetic activity in the mouse formalin test following po administration.     

Discrete residues in the c(2)b domain of synaptotagmin I independently specify endocytic rate and synaptic vesicle size

It has been demonstrated that synapses lacking functional synaptotagmin I (Syt I) have a decreased rate of synaptic vesicle endocytosis. Beyond this, the function of Syt I during endocytosis remains undefined. Here, we demonstrate that a decreased rate of endocytosis in syt(null) mutants correlates with a stimulus-dependent perturbation of membrane internalization, assayed ultrastructurally. We then separate the mechanisms that control endocytic rate and vesicle size by mapping these processes to discrete residues in the Syt I C(2)B domain. Mutation of a poly-lysine motif alters vesicle size but not endocytic rate, whereas the mutation of calcium-coordinating aspartate residues (syt-D3,4N) alters endocytic rate but not vesicle size. Finally, slowed endocytic rate in the syt-D3,4N animals, but not syt(null) animals, can be rescued by elevating extracellular calcium concentration, supporting the conclusion that calcium coordination within the C(2)B domain contributes to the control of endocytic rate.     

A System for Cost and Reimbursement Control in Hospitals

This paper approaches the design of a regional or statewide hospital rate-setting system as the underpinning of a larger system which permits a regulatory agency to satisfy the requirements of various public laws now on the books or in process. It aims to generate valid interinstitutional monitoring on the three parameters of cost, utilization, and quality review. Such an approach requires the extension of the usual departmental cost and budgeting system to include consideration of the mix of patients treated and the utilization of various resources, including patient days, in the treatment of these patients. A sampling framework for the application of process-based quality studies and the generation of selected performance measurements is also included.     

Functional characterization of the creatine phosphokinase reactions in heart mitochondria and myofibrils]

The kinetic properties of MM-isozyme of creatine phosphokinase (CPK) bound to heart myofibrils have been determined experimentally. It has been shown that CPK isozymes bound to the heart myofibrils and mitochondria are electrophoretically different, but have very similar kinetic properties. For both isozymes the ATP formation reaction is preferable. However, in heart mitochondria the kinetic properties of CPK are compensated for by a tight functional coupling with ATP-ADP translocase. Due to this coupling the ATP formed in the course of oxidative phosphorylation can be used completely for creatine phosphate production in mitochondria. On the other hand, the kinetic properties of myofibrillar CPK isozyme are such that they provide for the effective utilization of creatine phosphate produced in mitochondria for rephosphorylation of AKP formed in the myofibrils during contraction. It is concluded that in the heart cells energy can be transferred from the mitochondria to the myofibrils by creatine phosphate molecules.