Blue Blocks Research Articles

Evans blue blocks P2X-purinoceptors in rat vas deferens.

In rat vas deferens, Evans blue 100 microM increased contractions elicited by high K+ and by noradrenaline but markedly reduced contractions elicited by the P2X-purinoceptor-selective agonist alpha,beta-methylene ATP (3 microM). The concentration-response curve of alpha,beta-methylene ATP was shifted to the right by Evans blue 30 microM and the maximal contraction was increased. In tissues incubated with nifedipine 10 microM, Evans blue 100 microM tended to increase the residual contraction elicited by noradrenaline and abolished the residual response to alpha, beta-methylene ATP (3 microM). The concentration-response curve of alpha,beta-methylene ATP was progressively shifted to the right by increasing concentrations of Evans blue in the presence of nifedipine; maximal contractions were increased by Evans blue 10 and 30 but not 100 microM. From the shifts to the right caused by Evans blue 30 microM, apparent pKB values of 5.9 (no nifedipine) and 6.0 (nifedipine present) were calculated. It is concluded that Evans blue blocks P2X-purinoceptors in rat vas deferens and in addition causes a non-receptor-specific enhancement of contractions.

Structural characterization of [VO(salicylhydroximate)(CH 3OH)] 3: Applications to the biological chemistry of vanadium(V)

The biological chemistry of vanadium has garnered increased attention due to the recent isolation of vanadium enzymes capable of nitrogenase [l] and bromoperoxidase [2,3] activities. The latter enzymes, isolated from marine algae, contain a mononuclear V(V) active site [4] that does not appear to require redox chemistry in the catalytic mechanism. It is well established that bacteria and algae often produce low molecular weight chelating agents (siderophores) which will sequester metal ions and facilitate the transport of these nutrients into the cell [5]. The two major classes of siderophores are based on catecholate and hydroxamate metal ligands [6]. Because vanadium bromoperoxidase is isolated from algae and bacteria, we felt that it would be interesting to examine the coordination chemistry of vanadium with hydroxamate ligands that might form the basis of vanadium sequestering agents for these organisms. In the process of our studies, we have isolated an intriguing trinuclear cluster composed of V03+ and salicylhydroxamic acid and report herein the structure and solution chemistry of this molecule. [VO(salicylhydroximate)(CHsOH)] a (1) can be prepared in 70% yield by the room temperature reaction of one equivalent of VO(acetylacetonate)z or VCla with salicylhydroxamic acid and three equivalents of NaOCHs or NaOH in methanol. Air acts as the oxidant to form deep blue solutions of 1. Slow evaporation of a methanol solution gave deep blue blocks which were suitable for X-ray crystallographic analysis. Crystallographic data for 1: monoclinic, space group P2Jc, a = 11.006(3), b = 15.722(7), c = 2 1.240(6) A; fi = 111.40(2)‘; v = 3422(2) A3, Z = 4; l(Mo Kor) =0.7107 A; crystal dimensions 0.42 X 0.49 X 0.52 mm3; p = 8.19 cm-l. The intensities of 4504 reflections were measured at room temperature (0 G26 < 453 on a P2r diffractometer using MO Ka radiation. The structure was solved using the SHELX-86 program. All nonhydrogen atoms were refined using anisotropic thermal parameters. Hydrogen atoms were located, but not refined, and placed at fixed distances (0.95 A) from bonded carbon atoms. All calculations were carried out using the SHELX-86 program. For Fig. 1. An ORTEP diagram of 1 with thermal ellipsoids at 30% probability. Selected mean bond lengths (A) and angles (“) for chemically equivalent bonds with range in parentheses: V=O, 1.59 (1.582-1.602); V-O,, 1.85 (1.8421.861); v-o,, 2.08 (2.061-2.096); V-O,., 2.12 (2.0902.143); V-On, 1.86 (1.858-1.868); V-N, 2.02 (2.0142.030); On-N, 1.37 (1.362-1.376); Cn-N, 1.33 (1.3181.339); Cn-0, 1.26 (1.260-1.275); V-V, 4.66 (4.6524.671); O=V-0,, 91 (88.1-92.7); O=V-O,, 108 (107.5108.6); O=V-On, 94 (93.8-94.7); O=V-N, 98 (97.098.1); O=V-0,, 165 (163.1-166.7); V-N-On, 120 (119.5-120.6); N-0,-V, 120 (119.4-120.2).

Responses of Mongoloid children to colored block presentation.

In an earlier study, Gramza and Witt (1969) examined choices of colored blocks in the play of 4- and 5-yr.-old normal children. The present study investigated the responses of a group of Mongoloid children presented with the same colored blocks. Only limited behavioral research has been done with Mongoloids and apparently no investigation has focused upon color preferences or block play in Mongolo~d children. The objectives of this study were to provide comparative data concerning the effects of color on block choices of Mongoloids and to examine block play itself in Mongoloid children. The test group consisted of 5 males and G females with a CA range of 66 to 95 mo. (144 = 81.5 mo.), an MA range of 23 to 53 mo. (M = 33.5 mo.) and an IQ (StanfordBinet Scale) range of < 30 to 56. Each was given Trials I, 11, and IV (limited availability of Ss prompted arbitrary exclusion of Trial 111) using red, blue, green and gray blocks exactly as described by Gramza and Witt (1969); as in the earlier study, blocks were presented in single color piles in Trials I and I1 while one multicolor block pile was presented in Trial IV. The only modifications of the earlier experimental method were verbal instructions were given at the imitative as well as the receptive language level and a passive instructor remained in the room with S during each session. No significant indications of preference for any one color or position were detected in Ss' use of blocks. In Trials I and I1 when single color piles were presented, in 7 of 17 cases where Ss made block choices, only a single color was used in each case; in the multicolor pile presentation of Trial IV, in all 9 cases where Ss chose blocks, more than one color was used. No clear trend was present in the number of blocks used per S/per trial. The following two major patterns were observed in the use Ss made of the blocks: G Ss (MA range 26 to 38 mo.) used blocks in a nonstructured fashion and in this group 2 Ss vigorously threw and scattered blocks about the test room while 4 SS simply relocated blocks in a manner thar lacked any discernable order; 5 Ss (MA range 23 to 53 mo.) used blocks in an ordered way which resulted in linear, square and vertically stacked groupings.

GLIA IN THE LEECH CENTRAL NERVOUS SYSTEM: PHYSIOLOGICAL PROPERTIES AND NEURON-GLIA RELATIONSHIP.

GLIA IN THE LEECH CENTRAL NERVOUS SYSTEM: PHYSIOLOGICAL PROPERTIES AND NEURON-GLIA RELATIONSHIP.