Perceived levels of self-disclosure, mental health, and helpfulness of group leaders.

Studied the relationship between therapist self-disclosure, mental health, and helpfulness as perceived by group members and determined if a member's perception of the group leader is a function of the member's own level of self-disclosure and mental health. Data were collected from 6 university encounter groups by using ranks for group member variables and rating scales for perceptions of group leaders. Perceptions of group leader self-disclosure, mental health, and helpfulness were all positively correlated. No differences occurred in the perceptions of group leaders as a result of the members' ranked levels of self-disclosure and mental health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"I Am Us": Negative Stereotypes as Collective Threats.

Collective threat is the fear that an ingroup member's behavior might reinforce a negative stereotype of one's group. In a field study, self-reported collective threat was higher in stereotyped minorities than in Whites and was linked to lower self-esteem in both groups. In 3 experimental studies, a potentially poor performance by an ingroup member on a stereotype-relevant task proved threatening, as evidenced by lower self-esteem among minority students in 2 experiments and women in a 3rd experiment. The latter study demonstrated the generality of collective threat. Collective threat also undermined academic performance and affected self-stereotyping, stereotype activation, and physical distancing from the ingroup member. Results further suggest that group identification plays a role in whether people use an avoidance or challenge strategy in coping with collective threat. Implications for theories of social identity and stigmatization are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identification of group VS116 strains among Borrelia burgdorferi sensu lato grown from the hard tick, Ixodes ricinus (Linnaeus, 1758) by off-coupled restriction fragment length polymorphism analysis

The degree of chemical shift similarity for homologous proteins has been determined from a chemical shift database of over 50 proteins representing a variety of families and folds, and spanning a wide range of sequence homologies. After sequence alignment, the similarity of the secondary chemical shifts of C alpha protons was examined as a function of amino acid sequence identity for 37 pairs of structurally homologous proteins. A correlation between sequence identity and secondary chemical shift rmsd was observed. Important insights are provided by examining the sequence identity of homologous proteins versus percentage of secondary chemical shifts that fall within 0.1 and 0.3 ppm thresholds. These results begin to establish practical guidelines for the extent of chemical shift similarity to expect among structurally homologous proteins.     

Amino acid sequence, spectral, oxygen-binding, and autoxidation properties of indoleamine dioxygenase-like myoglobin from the gastropod mollusc Turbo cornutus

Myoglobin was isolated from the radular muscle of the archaeogastropod mollusc Turbo cornutus (Turbinidae). This myoglobin is a monomer carrying one protoheme group; the molecular mass was estimated by SDS-PAGE to be about 40 kDa, 2.5 times larger than that of usual myoglobin. The cDNA-derived amino acid sequence of 375 residues was determined, of which 327 residues were identified directly by chemical sequencing of internal peptides. The amino acid sequence of Turbo myoglobin showed no significant homology with any other usual 16-kDa globins, but showed 36% identity with the myoglobin from Sulculus diversicolor (Haliotiidae) and 27% identity with human indoleamine 2,3-dioxygenase, a tryptophan-degrading enzyme containing heme. Thus, the Turbo myoglobin can be counted among the myoglobins which evolved from the same ancestor as that of indoleamine 2,3-dioxygenase. The absorbance ratio of gamma to CT maximum (gamma/CT) of Turbo metmyoglobin was 17.8, indicating that this myoglobin probably possesses a histidine residue near the sixth coordination position of heme iron. The Turbo myoglobin binds oxygen reversibly. Its oxygen equilibrium properties are similar to those of Sulculus myoglobin, giving P50 = 3.5 mm Hg at pH 7.4 and 20 degrees C. The pH dependence of autoxidation of Turbo oxymyoglobin was quite different from that of mammalian myoglobin, suggesting a unique protein folding around the heme cavity of Turbo myoglobin. A kinetic analysis of autoxidation indicates that the amino acid residue with pKa = 5.4 is involved in the reaction. The autoxidation reaction was enhanced markedly at pH 7.6, but not at pH 5.5 and 6.3 in the presence of tryptophan. We suggest that a noncatalytic binding site for tryptophan, in which several dissociation groups with pKa > or = 7.6 are involved, remains in Turbo myoglobin as a relic of molecular evolution.     

Interacting effects of control, motivation, group practice, and problem difficulty on attempted leadership.

"Fifty-one groups of five subjects each were studied on ten brief trials to examine the effects of differing motivation and amount of control in the tendency to attempt leadership in a group situation." Results suggest "that a member's attempted leadership is higher, the higher his control and the higher the group's motivation." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Possibility for detecting HIV-1 in bone transplant by PCR using the HIV-1 microtiter plate assay

It is known that HIV can be transmitted by allogenous bone transplantation. Hitherto neither chemical nor physical methods have existed to allow reliable disinfection and sterilization of bone specimens without reducing osteogenetic potency. Only demonstration or exclusion of the presence of HIV-1 in a bone specimen guarantees that infection will not occur. The method now presented for HIV detection is based on a polymerase chain reaction (PCR). This HIV microtiter-plate assay combines amplification of DNA molecules with a staining reaction. In cultures containing HIV-infected cells definite detection of viruses was possible when 50-100 cells per specimen were infected. Examination of 137 HIV-negative and 25 HIV-positive bone specimens showed sensitivity of 96% and specificity of 97.8% for the test. In subsequent studies, after drying on filter paper viral DNA was again demonstrable by the PCR. This means safe handling and uncomplicated transportation of non-infectious specimens to a central analysis laboratory are possible. This HIV test offers the possibility of quick and safe demonstration that specimens are free of HIV and is therefore likely to enhance the safety of bone transplantation considerably.     

The catalytic mechanism of beta-lactamases: NMR titration of an active-site lysine residue of the TEM-1 enzyme

Beta-Lactamases are widespread in the bacterial world, where they are responsible for resistance to penicillins, cephalosporins, and related compounds, currently the most widely used antibacterial agents. Detailed structural and mechanistic understanding of these enzymes can be expected to guide the design of new antibacterial compounds resistant to their action. A number of high-resolution structures are available for class A beta-lactamases, whose catalytic mechanism involves the acylation of a serine residue at the active site. The identity of the general base which participates in the activation of this serine residue during catalysis has been the subject of controversy, both a lysine residue and a glutamic acid residue having been proposed as candidates for this role. We have used the pH dependence of chemical modification of epsilon-amino groups by 2,4,6,-trinitrobenzenesulfonate and the pH dependence of the epsilon-methylene 1H and 13C chemical shifts (in enzyme selectively labeled with [epsilon-13C]lysine) to estimate the pKa of the relevant lysine residue, lysine-73, of TEM-1 beta-lactamase. Both methods show that the pKa of this residue is > 10, making it very unlikely that this residue could act as a proton acceptor in catalysis. An alternative mechanism in which this role is performed by glutamate-166 through an intervening water molecule is described.     

The effects of strychnine, bicuculline, and ketamine on ''immersion-inhibited'' dorsal horn convergent neurons in intact and spinalized rats

Dinucleoside(5',5') polyphosphates (ApnA, ApnG, GpnG, n=3-6) are new group of hormones controlling important biological processes. Because some of the dinucleoside(5',5') polyphosphates are commercially not available purification of chemical synthesised dinucleoside(5',5') polyphosphates became necessary in order to test their physiological and pharmacological properties. It was the aim of this study to find a method which allows purification of 0.1-0.2 g quantities of dinucleoside polyphosphates by analytical HPLC columns yielding products with impurities lower than 1.0%. Adenosine(5')-polyphospho-(5')guanosines were synthesised by mixing the corresponding mononucleotides. The reaction results in a complex mixture of ApnA, ApnG and GpnG (with n=3-6 in all cases). The reaction mixture was concentrated on a preparative C18 reversed-phase column. The concentrate was displaced on a reversed-phase stationary. As a result of displacement chromatography, anion-exchange chromatography in gradient modus yielded baseline separated dinucleoside polyphosphates (homogeneity of the fractions>99%). The identity of the substances were determined by matrix assisted laser desorption ionisation mass spectrometry.     

Perceived entitativity, stereotype formation, and the interchangeability of group members.

The authors investigated the effects of perceived entitativity of a group on the processing of behavioral information about individual group members and the extent to which such information was transferred to other group members. The results of 3 experiments using a savings-in-relearning paradigm showed that trait inferences about a group member, based on that member's behavior, were stronger for low entitative groups and for collections of individuals. However, the transference of traits from 1 group member to other members of the group was stronger for high entitative groups. These results provide strong evidence that the perception of high entitativity involves the abstraction of a stereotype of the group and the transfer of that stereotype across all group members. Implications for group impression formation and stereotyping are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cloning, chromosomal localization, and tissue expression of autotaxin from human teratocarcinoma cells

Autotaxin, a potent human tumor cell motility-stimulating exophosphodiesterase, was isolated and cloned from the human teratocarcinoma cell line NTera2D1. The deduced amino acid sequence for the teratocarcinoma autotaxin has 94% identity to the melanoma-derived protein, 90% identity to rat brain phosphodiesterase I/nucleotide pyrophosphatase (PD-I alpha), and 44% identity to the plasma cell membrane marker PC-I. Utilizing polymerase chain reaction screening of the CEPH YAC library, we localized the autotaxin gene to human chromosome 8q23-24. Northern blot analysis of relative mRNA from multiple human tissues revealed that autotaxin mRNA steady state expression is most abundant in brain, placenta, ovary, and small intestine.     

A case pf spontaneous deletion in the FMR1 gene in a patient with the Martin-Bell syndrome]

Current models of Cr(VI) carcinogenesis suggest an important role for Cr(IV) as an intermediate, toxic, carcinogenic species, but direct chemical evidence has been lacking. This is because Cr(IV) is a highly reactive oxidation state of Cr and few Cr(IV)-based compounds are known that can be used as a model compound containing a biological ligand. This study reports the isolation of such a stable Cr(IV) complex. The Cr(IV)-GSH complex has been synthesized through the reaction of Cr(VI) with GSH. Its electron paramagnetic resonance (EPR) spectrum exhibits g = 1.9629 and a peak-to-peak line width of 480 G in aqueous medium as well as in the powder form. Magnetic susceptibility measurements showed that the compound has a magnetic moment of 2.53 Bohr magneton per Cr, establishing that the Cr ion has two unpaired electrons, hence its identity as Cr(IV). The Cr(IV)-GSH complex is able to generate hydroxyl (.OH) radical in the presence of molecular oxygen in aqueous medium. Catalase inhibited the .OH radical generation while H2O2 enhanced it, indicating that the .OH radical was generated via a Fenton-like reaction, H2O2 being generated as an intermediate in the reduction of molecular oxygen. Metal ion chelators, deferoxamine and 1,10-phenanthroline, attenuated the generation of Cr(IV)-mediated .OH radical. In the case of deferoxamine, a deferoxamine-derived free radical was generated as shown by EPR measurements. The results imply that Cr(IV) may play an important role in the mechanism of Cr(VI)-induced carcinogenesis and Cr(IV)-GSH can be used as a model compound to study the role of Cr(IV) in this mechanism.     

Biomimetic metabolism of artelinic acid by chemical cytochrome P-450 model systems

PURPOSE: To study the reaction of artelinic acid with chemical model systems of cytochrome P-450 as a means of obtaining authentic samples of the putative metabolites necessary for identification of the mammalian metabolites of artelinic acid. METHODS: Artelinic acid was reacted with different organic complexes of iron(II). The reaction products were isolated and characterized by NMR and thermospray mass spectroscopy. RESULTS: Five compounds which are putative metabolites of artelinic acid were isolated from these reactions and unambiguously identified, while the identity of two other compounds await final confirmation. CONCLUSIONS: Standards of possible metabolites of artelinic acid can be produced by the reaction of the compound with ferrous complexes that may simulate cytochrome P-450 catalyzed metabolism of xenobiotics. This approach may provide a simple and versatile method for the formation of metabolites of artemisinin compounds which is more advantageous than previous approaches with fungal-based systems.     

Membership has its (epistemic) rewards: Need for closure effects on in-group bias.

Three studies examined the impact of the need for cognitive closure on manifestations of in-group bias. All 3 studies found that high (vs. low) need for closure increased in-group favoritism and out-group derogation. Specifically, Study 1 found a positive relation between need for cognitive closure and both participants' ethnic group identification and their collective self-esteem. Studies 2 and 3 found a positive relation between need for closure and participants' identification with an in-group member and their acceptance of an in-group member's beliefs and attitudes. Studies 2 and 3 also found a negative relation between need for closure and participants' identification with an out-group member and their acceptance of an out-group member's beliefs and attitudes. The implications of these findings for the epistemic function of in-groups are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Salience of gender and sex composition of ad hoc groups: An experimental test of distinctiveness theory.

Examined whether the salience of an individual group member's gender would depend on the group's sex composition. According to W. J. McGuire's (1984) distinctiveness theory, even for "momentary" or ad hoc groups, gender would be more salient in the spontaneous self-concepts of members of the minority sex in mixed-sex groups than in other conditions. To test this prediction experimentally, 192 undergraduates (aged 17–55 yrs) were divided into 3-person groups in which the sex composition was manipulated. This resulted in 4 types: all male, all female, lone male, and lone female. Within these group contexts, Ss responded to 2 open-ended probes of spontaneous self-concept (i.e., "Tell me what you are" and "Tell me what you are not"), with order counterbalanced, and subsequently completed a structured measure of gender identity (Personal Attributes Questionnaire). Chi-square analyses of whether gender was mentioned on the "Tell me about yourself" probe supported the distinctiveness theory. (18 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Centrality in sociocognitive networks and social influence: An illustration in a group decision-making context.

Social influence in consensus formation was examined using a notion of sociocognitive network. Given the robustness of shared information in determining group decisions, the authors propose the concept of a sociocognitive network that captures the degree of members' knowledge-sharing prior to group interaction. A link connecting a given pair of members represents the amount of information that the pair shares before interaction. As in a regular social network, a member's status can be defined by the centrality in the network; the more information a member shares with others, the more cognitively central the member is in the group. The authors hypothesized that a cognitively central member would acquire pivotal power in a group and exert more influence on consensus than would peripheral members, independently of the member's preference majority or minority status. The results of two studies supported these predictions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ego identity status, adjustment, and academic achievement.

81 male undergraduates were interviewed to determine their identity-status, were administered the Zuckerman Mood Affect Adjective Checklist (MAACL), and their GPAs and Scholastic Aptitude Test (SAT) scores were obtained. Analyses of variance showed: (a) no differences between groups on MAACL subscales of identity, depression, and anxiety; (b) that SAT scores were not associated with identity status; and (c) that the relationship between identity achievement and GPA is strong. It is concluded that identity status and college performance cannot be attributed to differences in adjustment, and that college students who have achieved a strong identity perform better, are more task-oriented, and their work is more meaningful to them. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relationships among asymmetry in task dependence, perceived helping behavior, and trust.

Social relations analyses involving 132 working relationships among 60 individuals from 29 teams revealed that an increase in a team member's task dependence on another team member was associated with higher levels of perceived help from and interpersonal trust in that specific team member, provided the other member was highly task dependent on the focal member. The degree to which an actor perceived a relationship with a partner to be helpful partially mediated the relationship between task dependence and trust. These findings highlight the importance of attending to asymmetries in task dependence and provide valuable insights into mechanisms that can explain the development of trust in organizational work teams. (PsycINFO Database Record (c) 2010 APA, all rights reserved)