Impact of videogame play on the brain's microstructural properties: cross-sectional and longitudinal analyses.

Videogame play (VGP) has been associated with numerous preferred and non-preferred effects. However, the effects of VGP on the development of microstructural properties in children, particularly those associated with negative psychological consequences of VGP, have not been identified to date. The purpose of this study was to investigate this issue through cross-sectional and longitudinal prospective analyses. In the present study of humans, we used the diffusion tensor imaging mean diffusivity (MD) measurement to measure microstructural properties and examined cross-sectional correlations with the amount of VGP in 114 boys and 126 girls. We also assessed correlations between the amount of VGP and longitudinal changes in MD that developed after 3.0±0.3 (s.d.) years in 95 boys and 94 girls. After correcting for confounding factors, we found that the amount of VGP was associated with increased MD in the left middle, inferior and orbital frontal cortex; left pallidum; left putamen; left hippocampus; left caudate; right putamen; right insula; and thalamus in both cross-sectional and longitudinal analyses. Regardless of intelligence quotient type, higher MD in the areas of the left thalamus, left hippocampus, left putamen, left insula and left Heschl gyrus was associated with lower intelligence. We also confirmed an association between the amount of VGP and decreased verbal intelligence in both cross-sectional and longitudinal analyses. In conclusion, increased VGP is directly or indirectly associated with delayed development of the microstructure in extensive brain regions and verbal intelligence.

Retinoic acid enhances the gene expression of human polymeric immunoglobulin receptor (pIgR) by TNF-alpha.

In this study, the detailed mechanisms for the effects of vitamin A on the expression of polymeric immunoglobulin receptor (pIgR) were examined. Expression of the pIgR by tumour necrosis factor (TNF-alpha) was enhanced by the addition of all-trans retinoic acid (ATRA) or 9-cis retinoic acid (9CRA). This enhancement was mediated mainly by RARalpha, and regulated at the transcriptional level. Transcription factor nuclear factor-kappaB (NF-kappaB) binding and activation were not influenced by addition of ATRA. These data imply that RA, in combination with TNF-alpha, could up-regulate the expression of pIgR. In addition, we hypothesize that up-regulation of pIgR by RA is controlled through the RAR-dependent signalling pathway and that it plays a role in enhancement of mucosal immunity.

Involvement of EphA2 in the formation of the tail notochord via interaction with ephrinA1.

Eph receptors have been implicated in cell-to-cell interaction during embryogenesis. We generated EphA2 mutant mice using a gene trap method. Homozygous mutant mice developed short and kinky tails. In situ hybridization using a Brachyury probe found the notochord to be abnormally bifurcated at the caudal end between 11.5 and 12.5 days post coitum. EphA2 was expressed at the tip of the tail notochord, while one of its ligands, ephrinA1, was at the tail bud in normal mice. In contrast, EphA2-deficient notochordal cells were spread broadly into the tail bud. These observations suggest that EphA2 and its ligands are involved in the positioning of the tail notochord through repulsive signals between cells expressing these molecules on the surface.

Replication factors MCM2 and ORC1 interact with the histone acetyltransferase HBO1.

The minichromosome maintenance (MCM) proteins, together with the origin recognition complex (ORC) proteins and Cdc6, play an essential role in eukaryotic DNA replication through the formation of a pre-replication complex at origins of replication. We used a yeast two-hybrid screen to identify MCM2-interacting proteins. One of the proteins we identified is identical to the ORC1-interacting protein termed HBO1. HBO1 belongs to the MYST family, characterized by a highly conserved C2HC zinc finger and a putative histone acetyltransferase domain. Biochemical studies confirmed the interaction between MCM2 and HBO1 in vitro and in vivo. An N-terminal domain of MCM2 is necessary for binding to HBO1, and a C2HC zinc finger of HBO1 is essential for binding to MCM2. A reverse yeast two-hybrid selection was performed to isolate an allele of MCM2 that is defective for interaction with HBO1; this allele was then used to isolate a suppressor mutant of HBO1 that restores the interaction with the mutant MCM2. This suppressor mutation was located in the HBO1 zinc finger. Taken together, these findings strongly suggest that the interaction between MCM2 and HBO1 is direct and mediated by the C2HC zinc finger of HBO1. The biochemical and genetic interactions of MYST family protein HBO1 with two components of the replication apparatus, MCM2 and ORC1, suggest that HBO1-associated HAT activity may play a direct role in the process of DNA replication.

A novel class of orally active non-peptide bradykinin B2 receptor antagonists. 2. Overcoming the species difference between guinea pig and man.

Recently we reported the identification of a series of 8-[[3-(N-acylglycyl-N-methylamino)-2, 6-dichlorobenzyl]oxy]-3-halo-2-methylimidazo[1,2-a]pyridines as the first orally active non-peptide bradykinin (BK) B2 receptor antagonists (1-3). These compounds inhibited the specific binding of [3H]BK to guinea pig ileum membrane preparations expressing B2 receptors with nanomolar IC50's and also displayed in vivo functional antagonistic activities against BK-induced bronchoconstriction in guinea pigs at 1 mg/kg by oral administration. However, it was found that their affinities for the B2 receptors in human A-431 cells (human epidermoid carcinoma) were much lower. Intensive modifications of the terminal substituents at the glycine moiety elucidated the structure-activity relationships (SAR) for human B2 receptors, leading to an extended basic framework which incorporated a novel key pharmacophore. Thus, we overcame the species difference and identified the first clinical candidate 18c (FR167344) with IC50's of 0.66 and 1.4 nM for guinea pig ileum and human A-431 cells, respectively. This compound displayed in vivo functional antagonistic activity against BK-induced bronchoconstriction in guinea pigs with an ED50 value of 0.17 mg/kg by oral administration. This novel non-peptide B2 antagonist is extremely potent both in vitro and in vivo by oral administration and is expected to be the first member of a new class of drug for the treatment of various inflammatory diseases.

A novel class of orally active non-peptide bradykinin B2 receptor antagonists. 3. Discovering bioisosteres of the imidazo[1,2-a] pyridine moiety.

Recently we reported on overcoming the species difference of our first orally active non-peptide bradykinin (BK) B2 receptor antagonists, incorporating an 8-[[3-(N-acylglycyl-N-methylamino)-2, 6-dichlorobenzyl]oxy]-3-halo-2-methylimidazo[1,2-a]pyridine skeleton, leading to identification of the first clinical candidate 4a (FR167344). With this potent new lead compound in hand, we then investigated further refinement of the basic framework by replacement of the imidazo[1,2-a]pyridine moiety and discovered several bioisosteric heterocycles. Extensive optimization of these new heteroaromatic derivatives revealed the detailed structure-activity relationships (SAR) around the imidazo[1, 2-a]pyridine ring and the 2,6-dichlorobenzyl moiety, leading to the discovery of our second clinical candidate 87b (FR173657) which inhibited the specific binding of [3H]BK to recombinant human B2 receptors expressed in Chinese hamster ovary (CHO) cells and guinea pig ileum membrane preparations expressing B2 receptors with IC50's of 1.4 and 0.46 nM, respectively. This compound also displayed excellent in vivo functional antagonistic activity against BK-induced bronchoconstriction in guinea pigs with an ED50 value of 0.075 mg/kg by oral administration. Further modifications of the terminal substituents on the pyridine moiety led to a novel pharmacophore and resulted in the identification of 99 (FR184280), whose IC50 value for human B2 receptors (0.51 nM) was comparable to that of the second-generation peptide B2 antagonist Icatibant.

Molecular maturation and functional expression of mouse polymeric immunoglobulin receptor.

Mouse polymeric immunoglobulin receptor (pIgR) cDNA was stably introduced into a hamster-derived fibroblastic cell line, Chinese hamster ovary (CHO) cell, by the calcium phosphate method. Surface expression of pIgR was detected by immunostaining and FACS analysis. The immunoprecipitated products of cell lysates revealed that the molecular mass of the most mature form of pIgR was approximately 120 kDa. Western blotting and metabolic labeling experiments followed by immunoprecipitation with an anti-mouse secretory component (SC) Ab demonstrated the existence of a 110 kDa immature form of pIgR. The reason for the existence of two forms of pIgR molecule was examined by conducting pulse-chase experiments which revealed the pIgR underwent molecular maturation. During this process, the 110 kDa form of pIgR was converted into a 120 kDa form by glycosylation. Moreover, tunicamycin treatment revealed the core form of pIgR had a molecular mass of approximately 100 kDa. The pIgR expressed on the surface of the transfectant could specifically bind and take up mouse polymeric IgA (MOPC 315), suggesting that, at least in this mouse system, cell type-specific molecules are not necessary for surface pIgR expression and polymeric immunoglobulin (pIg) binding and uptake.

Characterization of 30-kDa fragments derived from beta-conglycinin degradation process during germination and seedling growth of soybean.

The degradation process of beta-conglycinin, a vicilin-type glycosylated storage protein of soybean seeds, during germination and seedling growth was examined by concanavalin A blotting combined with polyacrylamide gel electrophoresis. We detected and analyzed the structures of key intermediary fragments of 30 kDa derived from beta-conglycinin degradation, they were proved to be single-domain type subunits of beta-conglycinin. We show here a degradation process of beta-conglycinin: beta-conglycinin is subjected to limited proteolysis at exposed regions on the molecular surface, like domain junctions, generating 30-kDa single-domain fragments before non-specific proteolysis.

Studies on cardiac ingredients of plants. XIII: Chemical modification of gitoxin to cardiotonic compounds without vascular effect.

Nitrated gitoxins (4) and bufotoxin homologues with various lengths of alkyl chain at C-3 of the steroid nucleus (10) were prepared from gitoxin (1). The pharmacological activities of the resulting compounds (4 and 10) were evaluated by measurement of inhibitory effect on NA+, K(+)-adenosine triphosphatase (ATPase) prepared from dog kidney, positive inotropic effect (PIE) on isolated guinea-pig papillary muscle preparations, and the effect on smooth muscle using the mesenteric artery from spontaneously hypertensive rats. Most of the compounds showed a smaller contractile effect on the arterial muscle. Among these compounds, gitoxin 3"-nitrate (4g) exhibited the most desirable biological activities, such as PIE comparable to that of 1, 1.25 times wider concentration-dependent range than 1, and lack of contractile activity on vascular muscle.

[Anti-tumor activity of zinostatin stimalamer (YM 881) examined by human hepatoma cells in vitro and VX2 liver tumor in vivo].

Anti-tumor activities of zinostatin stimalamer (YM 881) were examined using human hepatoma cell lines (SK-Hep1 and HuH 2) and VX2 liver tumor-bearing rabbits. YM881 inhibited the growth of human hepatoma cells in a dose-dependent manner. The IC50 values of YM881 against SK-Hep 1 and HuH 2 cells were 6.7 and 27 mM, respectively. In VX2 tumor-bearing rabbits, administration of YM 881 suspended in iodinated fatty acid ethylesters of poppyseed oil (YM 881/Lipiodol suspension, 0.2 mg/0.2 ml/body) into the hepatic artery showed significant (p < 0.01, vs sham-operated and Lipiodol-treated groups) inhibitory effects on the growth and pathological changes 1 and 2 weeks after administration. On the other hand, Lipiodol (0.2 ml/body) showed a tendency to inhibit the growth of VX2 tumor (p < 0.1, vs sham-operated group) 1 week after administration, but it showed only moderate effects on the VX2 tumor growth 2 weeks after administration. Minimal necrosis was observed 1 and 2 weeks after administration of Lipiodol, and these pathological findings were similar to those in the sham-operated group. From the present study, it is suggested that YM 881/Lipiodol suspension showed the anti-tumor activity against VX2 tumor-bearing rabbits, presumably due to the inhibition of the growth of hepatoma cell by YM 881 per se. On the other hand, Lipiodol is considered to augment the anti-tumor activity by maintaining high YM881 concentrations in tumor tissue.

Antianginal effects of YM-16151-4 in various experimental angina models.

The antianginal effects of YM-16151-4, a combined calcium entry blocking and beta 1-adrenoceptor blocking agent, were evaluated in various experimental angina models and compared with those of nifedipine and propranolol. In anesthetized dogs, YM-16151-4 (0.3 and 1 mg/kg intravenously, i.v.) increased coronary blood flow and reduced myocardial oxygen consumption (MVO2). In isolated dog coronary arteries, YM-16151-4 concentration-dependently inhibited 3,4-diaminopyridine-induced rhythmic contractions with an IC50 value of 91 nM. In anesthetized rats, YM-16151-4 also inhibited the ST-segment depression induced by vasopressin (0.5 U/kg i.v.) with an ED50 value of 29 mg/kg orally, (p.o.). Nifedipine was also effective in these models, but propranolol was not. In addition, YM-16151-4 (0.3 mg/kg i.v.) inhibited the ST-segment elevation in the epicardial ECG induced by coronary artery occlusion in anesthetized dogs. Propranolol (1 mg/kg i.v.) also inhibited this elevation, but nifedipine (0.003 mg/kg i.v.) did not. In anesthetized dogs, furthermore, the prolongation of PQ-interval induced by YM-16151-4 was almost the same as that induced by propranolol. These results demonstrate that YM-16151-4, in contrast to nifedipine and propranolol, is fully effective in these various types of angina models. Thus, YM-16151-4 is expected to prove a valuable antianginal agent in treatment of various types of angina pectoris, with these antianginal effects resulting from the sum of its calcium entry blocking and beta 1-adrenoceptor blocking activities.

A 5-lipoxygenase inhibitor, FR110302, inhibits ozone-induced airway hyperresponsiveness in guinea pigs and dogs.

Airway hyperresponsiveness is a key feature of asthma, and attenuating airway hyperresponsiveness is an important part of asthma therapy. In the present study we examined the inhibitory effect of a potent 5-lipoxygenase inhibitor, FR110302, on airway hyperresponsiveness induced by ozone exposure in guinea pigs and dogs. Respiratory resistance (Rrs) was measured by a forced oscillation method. Airway responsiveness was determined from the dose-response curve of Rrs to acetylcholine. Guinea pigs were exposed to 2.5 ppm ozone for 1 h. In a control group of guinea pigs, delta log PC100 (the index of the ozone-induced airway hyperresponsiveness) was 0.58 +/- 0.04 (log mg/ml). Treatment with FR110302 (10 or 100 mg/kg p.o.) significantly diminished delta log PC100 (10 mg/kg: 0.22 +/- 0.10; 100 mg/kg; 0.11 +/- 0.06). Dogs were exposed to 3 ppm ozone for 2 h. In a control group of dogs, delta log Dmin (another index of the ozone-induced airway hyperresponsiveness) was 1.24 +/- 0.15 (log unit). Treatment with FR110302 (1 or 3.2 mg/kg p.o.) significantly diminished delta log Dmin (1 mg/kg: 0.60 +/- 0.18; 3.2 mg/kg: 0.27 +/- 0.12). These results suggest that FR110302 may be a useful drug for attenuating airway hyperresponsiveness in asthmatic patients.

Adjuvant effect of interleukin-1 on the development of late asthmatic response in guinea pigs.

The adjuvant effect of silica and IL-1 in the development of late asthmatic responses (LARs) in guinea pigs was studied. Different doses of silica or recombinant human (rh) IL-1 (1 microgram) with Ascaris suum were used for the immunization. The serum IL-1 concentration was measured after the immunization. One week after the immunization, antigen was challenged and respiratory resistance (Rrs) was measured. Rrs increased silica dose dependently in the late phase, and the increment of Rrs in the late phase was significantly correlated with the serum IL-1 concentration (p < 0.05). In addition, rhIL-1 administration showed an increase in Rrs at the late phase. Antigen-specific IgE and IgG1 were also measured and were increased in guinea pigs immunized both with silica and rhIL-1.

Roles of the respiratory Na+ pump in bioenergetics of Vibrio alginolyticus.

Bioenergetic characteristics of Na+ pump-defective mutants of a marine bacterium Vibrio alginolyticus were compared with those of the wild type and revertant. Generation of membrane potential and motility at pH 8.5 in the mutants were completely inhibited by a proton conductor, carbonylcyanide m-chlorophenylhydrazone, whereas those in the wild type or revertant were resistant to the inhibitor. Motility and amino acid transport were driven by the electrochemical potential of Na+ not only in the wild type or revertant but also in the mutants. In the absence of the proton conductor, motility and amino acid transport of the mutants did not significantly differ from those of the wild type or revertant even at pH 8.5, where the Na+ pump has maximum activity. Therefore, the electrochemical potential of Na+ in the mutants seemed to be maintained at a normal level by a respiration-dependent H+ pump and Na+/H+ antiporter. On the other hand, growth of the mutants became defective as the medium pH increased, especially on minimal medium. These results indicate that the Na+ pump is an important energy-generating mechanism when nutrients are limited at alkaline pH.

Vasodilator effects of cepharanthine, a biscoclaurine alkaloid, on cutaneous microcirculation in the rabbit.

Cutaneous microcirculatory responses to intravenous administration of cepharanthine (CT), a biscoclaurine alkaloid, isolated from Stephania cepharantha, were studied in a transparent round chamber installed in a rabbit ear, under conscious conditions. Vital-microscopic observations were made visually with a microscope-closed TV system and microphotoelectric plethysmography. Following the CT administration in doses of 1.0 and 3.0 mg/kg, an enhancement of rhythmic perfusion of microvascular blood due to vasomotion was developed for a period of 1 h or longer, although no appreciable change was observed following CT administration at 10.0 mg/kg. The microvascular dilator effect of CT appeared to have no direct association with systemic hemodynamics, based on the additional measurements of heart rate, blood pressure, carotid blood flow and auricular arterial blood flow.

Effects of acupuncture needle application upon cutaneous microcirculation of rabbit ear lobe.

Microcirculatory effects of the application of an acupuncture needle (32-gauge, silver) to the back, corresponding to Geshu (B17) in human beings, were studied in vivo by microscope, using a transparent ear chamber in conscious rabbits. Although no striking findings were obtained during the needle application for a period of 30 minutes, it was clearly observed that the microvascular blood flow increases gradually in parallel with augmenting spontaneous rhythmic fluctuation of the vessel diameter, namely vasomotion, throughout a continuous observation period longer than 2 hours following release from the needle application. Diameters of arterioles and venules at the full-dilating phases of vasomotion reached levels higher than 200% and 250% of the initial values just before application of the needle, respectively. The clinical efficacy of acupuncture was suggested to be explained at least in part by the increased rhythmic microvascular blood flow in parallel with vasomotion, from the physiological point of view based on the previous investigations.

Assay of alpha-cysteine proteinase inhibitor in serum or plasma.

A new proteinase inhibitor has recently been found in human serum or plasma which specifically inhibits cysteine proteinases such as ficin, papain, bromelain and cathepsin B. However, serum contains alpha 2-macroglobulin which also inhibits these cysteine proteinases and, consequently, interferes with the assay of the new alpha-cysteine proteinase inhibitor. Therefore, assay of the inhibitor in serum has not been established previously. In the present method, the alpha 2-macroglobulin is inactivated by preincubating the serum in methylamine solution at 55 degrees C, while the alpha-cysteine proteinase inhibitor retains its activity. The inhibitory power against cysteine proteinases is found to be due mainly to this protein in human serum. This inhibitor is also found in mammals such as cows, pigs and rats. Vitamin E deficient rats show a very high inhibitor level. Therefore, the present method will enable us to investigate the relation between diseases and the activity of the alpha-cysteine proteinase inhibitor. Also, this method is simple and inexpensive. The necessary amount of serum is only 10 microliter.