Hostile attributional bias and aggressive behavior in global context.

We tested a model that children's tendency to attribute hostile intent to others in response to provocation is a key psychological process that statistically accounts for individual differences in reactive aggressive behavior and that this mechanism contributes to global group differences in children's chronic aggressive behavior problems. Participants were 1,299 children (mean age at year 1 = 8.3 y; 51% girls) from 12 diverse ecological-context groups in nine countries worldwide, followed across 4 y. In year 3, each child was presented with each of 10 hypothetical vignettes depicting an ambiguous provocation toward the child and was asked to attribute the likely intent of the provocateur (coded as benign or hostile) and to predict his or her own behavioral response (coded as nonaggression or reactive aggression). Mothers and children independently rated the child's chronic aggressive behavior problems in years 2, 3, and 4. In every ecological group, in those situations in which a child attributed hostile intent to a peer, that child was more likely to report that he or she would respond with reactive aggression than in situations when that same child attributed benign intent. Across children, hostile attributional bias scores predicted higher mother- and child-rated chronic aggressive behavior problems, even controlling for prior aggression. Ecological group differences in the tendency for children to attribute hostile intent statistically accounted for a significant portion of group differences in chronic aggressive behavior problems. The findings suggest a psychological mechanism for group differences in aggressive behavior and point to potential interventions to reduce aggressive behavior.

The effect of prenatal or early postnatal irradiation on the production of anti-arsonate antibodies and Cross-reactive idiotypes

Preliminary studies on the long-term effects of prenatal and early postnatal irradiation on the immune response to arsonate were performed using A/J mice. Pregnant mice were irradiated (0·5 Gy, X-rays) or sham-irradiated on a single occasion during gestation (between day 5 and 18 post-conception). Alternatively, newborn mice received the same treatment between day 2 and 7 after birth. Mice were immunized with keyhole limpet haemocyanin-arsonate (KLH-Ars) in adjuvant from 2 months after birth. The levels of specific antibodies to arsonate (anti-Ars) were measured by radioimmunoassay. In addition, the Ars-related cross-reactive idiotype (CRIA) was measured by the haemagglutination technique. In the primary response the titre of anti-Ars was reduced in animals that had been irradiated between day 12 and 15 of gestation. In the second response, in contrast, they had increased levels of anti-Ars. After immunization with KLH-Ars, high levels of CRIA were observed in all groups. However, in mice irradiated 18-20 days after conception the level of CRIA was often much higher than the level of anti-Ars, indicating that a large proportion of the CRIA-positive molecules were not specific for Ars. Thus, in this particular case, some specificity of the immune response was lost after irradiation. The expression of recurrent idiotypes may be a sensitive indicator of immunological perturbations after irradiation. © 1988 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.

Loss of a major idiotype (CRIA) after repopulation of irradiated mice.

The normal immune response of A/J mice against arsonate coupled to hemocyanin is characterized by a major recurrent cross-reactive Id, the CRIA. This Id is encoded by a single gene segment combination: VHidcr11-DFL16.1e-JH2 for the H chain and Vkidcr-Jk1 for the L chain. In this report, we show that lethal irradiation of A/J mice followed by reconstitution with autologous or syngeneic lymphoid cells results in loss of major CRIA Id expression in the response to arsonate. Different protocols were performed to repopulate the irradiated mice. First, lethally irradiated A/J mice were reconstituted by the transfer of syngeneic bone marrow cells. Second, A/J mice were lethally irradiated while their hind limbs were partially shielded. Third, lethally irradiated A/J mice received a transfer of syngeneic spleen cells. The three groups of mice produce high titers of antiarsonate antibodies completely devoid of CRIA DH-JH related idiotopes expression. Moreover, a lack of affinity maturation is observed in the secondary antiarsonate response of all irradiated and reconstituted mice. A transfer of syngeneic peritoneal cells or a transfer of primed T cells in irradiated and reconstituted A/J mice do not restore in a significant manner either the recurrent CRIA expression or the affinity maturation of the antiarsonate response. Our data suggest that the choice of this Id is not solely dictated by the Igh locus.

Cold crucible melting of reactive metals using combined DC and AC magnetic fields

Cold crucible furnace is widely used for melting reactive metals for high quality castings. Although the water cooled copper crucible avoids contamination, it produces a low superheat of the melt. Experimental and theoretical investigations of the process showed that the increase of the supplied power to the furnace leads to a saturation in the temperature rise of the melt, and no significant increase of the melt superheat can be obtained. The computer model of theprocess has been developed to simulate the time dependent turbulent flow, heat transfer with phase change, and AC and DC magnetohydrodynamics in a time varying liquid metal envelope. The model predicts that the supermimposition of a strong DC field on top of the normal AC field reduces the level of turbulience and stirring in the liquid metal, thereby reducing the heat loss through the base of the crucible and increasing the superheat. The direct measurements of the temperature in the commercial size cold crucbile has confirmed the computer redictions and showed that the addition of a DC field increased the superheat in molten TiAl from ~45C (AC field only) to ~81C (DC+AC fields). The present paper reports further predictions of the effect of a dDC field on top of the AC field and compares these with experimental data.

Prooxidant action of knipholone anthrone: Copper dependent reactive oxygen species generation and DNA damage

Knipholone (KP) and knipholone anthrone (KA) are natural 4-phenylanthraquinone structural analogues with established differential biological activities including in vitro antioxidant and cytotoxic properties. By using DNA damage as an experimental model, the comparative Cu(II)-dependent prooxidant action of these two compounds were studied. In the presence of Cu(II) ions, the antioxidant KA (3.1-200 [mu]M) but not KP (6-384 [mu]M) caused a concentration-dependent pBR322 plasmid DNA strand scission. The DNA damage induced by KA could be abolished by reactive oxygen species scavengers, glutathione and catalase as well as EDTA and a specific Cu(I) chelator bathocuproine disulfonic acid. In addition to Cu(II) chelating activity, KA readily reduces Cu(II) to Cu(I). Copper-dependent generation of reactive oxygen species and the subsequent macromolecular damage may be involved in the antimicrobial and cytotoxic activity of KA.

Antioxidant and antiinflammatory effect of Epilobium parviflorum Schreb

Epilobium parviflorum Schreb. (Onagraceae) is used for the treatment of benign prostatic hyperplasia (BPH), but its biological action is not entirely identified. This paper aims to report data on E. parviflorum with respect to its antioxidant and antiinflammatory effects. The aqueous acetone extract of E. parviflorum showed higher antioxidant effect in the DPPH assay than well known antioxidants and inhibited the lipid peroxidation determined by the TBA assay (IC(50) = 2.37 +/- 0.12 mg/mL). In concentrations of 0.2-15.0 microg/mL the extract possessed a protective effect, comparable to catalase (250 IU/mL), against oxidative damage, generated in fibroblast cells. In the COX inhibition assay E. parviflorum decreased the PGE(2) release, so showing inhibition of the COX-enzyme (IC(50) = 1.4 +/- 0.1 microg/mL).

Epilobium parviflorum Schreb. - in vitro study of biological action

Epilobium parviflorum Schreb. (Onagraceae) is used for the treatment of benign prostatic hyperplasia (BPH), which is regarded as an endocrine disorder caused by age-related hormone imbalance and increased oxidative damage [1,2,3]. Epilobium can moderate the obstructive and the irritative symptoms of BPH [1] but its biological action is not entirely identified. E. parviflorum is rich in phytosterols, flavonoids (myricetin, quercetin, kaempferol and their glycosides), phenolic acids, catechins, ellagi- and gallotannins [4]. The potential biological effects of Epilobium parviflorum Schreb. have been investigated, in respect to its antioxidant, anti-inflammatory, enzyme-inhibitory and anti-androgenic effect. The whole-plant water extract showed higher antioxidant effect (IC50=1.65±0.05µg/mL) in DPPH assay than Trolox or ascorbic acid and inhibited the lipid peroxidation examined in TBA assay (IC50=2.31±0.18mg/mL). In concentrations 0.20-15.00µg/mL the extract possessed a protective effect comparable to catalase enzyme (2500 IU/mL), against oxidative damage generated on fibroblast cells. The examination of the COX-inhibitory effect showed that E. parviflorum had an anti-inflammatory effect (IC50=1.38±0.08µg/mL). Investigation of steroid receptor binding ability and the aromatase enzyme-inhibition showed negative results in the concentration range examined.

Cytology And Cytochemistry Of Hemocytes Of Mytilus-Edulis And Their Responses To Experimentally Injected Carbon Particles

Hemocytes of Mytilus edulis were examined cytologically and cytochemically. On the basis of structure, staining reactions, and phagocytic behavior, they were divided into two main groups: basophilic hemocytes and eosinophilic granular hemocytes (granulocytes). The basophilic cells were further divided into small lymphocytes and larger phagocytic macrophages reactive for lysosomal hydrolases. Mitosis was observed in granulocytes and in small lymphoid cells, believed to be the stem cells for the basophilic cell line. A few cells appeared to be intermediate between lymphocytes and small granulocytes. Macrophages were the main cell type involved in the clearance of injected carbon particles. However, granulocytes did show some phagocytic activity. Brown cells displaying apparent amoebocytic behavior were found to contain Fe3+ and Pb2+ in cytoplasmic inclusions, some of which were also reactive for β-glucuronidase and glucosaminidase. These cells appear to have a separate origin from the hemocytes.