Xwnt-8b: a maternally expressed Xenopus Wnt gene with a potential role in establishing the dorsoventral axis

In amphibian embryos, establishment of dorsal-ventral asymmetry is believed to involve dorsal-ventral differences in vegetally derived mesoderm-inducing signals and/or differences in the competence of animal hemisphere (ectodermal) cells to respond to these signals. Previous studies have shown that certain Wnt proteins can generate an ectopic dorsal axis when misexpressed, and that they do so by modifying the response of ectodermal cells to inducers. None of these Wnt proteins are expressed at an appropriate time to do so in vivo. In this study, we describe the isolation and characterization of a full length cDNA for the Xenopus Wnt gene, Xwnt-8b, whose biological activity and expression pattern suggest that it may be involved in establishment of the dorsoventral axis. Both maternal and zygotic Xwnt-8b transcripts undergo alternative splicing to generate mRNAs which encode two different forms of Xwnt-8b protein. During early cleavage stages Xwnt-8b transcripts are confined primarily to animal hemisphere blastomeres, while zygotically derived Xwnt-8b transcripts are restricted almost exclusively to a band of cells in the prospective forebrain of neurula and tailbud stage embryos. Ectopically expressed Xwnt-8b can completely rescue dorsal development of embryos ventralized by exposure to ultraviolet light, and can induce a complete secondary axis in wild-type embryos. Axis induction is observed only if Xwnt-8b is supplied prior to the onset of zygotic gene transcription. This biological activity, together with the presence of maternal Xwnt-8b transcripts in cells that will be induced to form the dorsal mesoderm, is consistent with the possibility that Xwnt-8b may be the endogenous agent that establishes asymmetry in the response of ectodermal cells to mesoderm-inducing signals, thereby initiating dorsal development.

The thrill of victory, the complexity of defeat: self-esteem and people's emotional reactions to success and failure

Low self-esteem people are assumed to have more severe emotional reactions to failure than are high self-esteem people, but this assumption has not received consistent empirical support. In this article the authors report 2 investigations that found that self-esteem differences of this sort emerge for emotions that directly implicate the self (e.g., pride, humiliation) but not for emotions that do not directly implicate the self (e.g., happiness, unhappiness). Additional evidence suggested that this occurs, in part, because low self-esteem people overgeneralize the negative implications of failure. The relevance of these findings for understanding the nature and functions of self-esteem is considered.

The thrill of victory, the complexity of defeat: self-esteem and people's emotional reactions to success and failure

Low self-esteem people are assumed to have more severe emotional reactions to failure than are high self-esteem people, but this assumption has not received consistent empirical support. In this article the authors report 2 investigations that found that self-esteem differences of this sort emerge for emotions that directly implicate the self (e.g., pride, humiliation) but not for emotions that do not directly implicate the self (e.g., happiness, unhappiness). Additional evidence suggested that this occurs, in part, because low self-esteem people overgeneralize the negative implications of failure. The relevance of these findings for understanding the nature and functions of self-esteem is considered.

Subunits of the Saccharomyces cerevisiae signal recognition particle required for its functional expression

The signal recognition particle (SRP) is an evolutionarily conserved ribonucleoprotein (RNP) complex that functions in protein targeting to the endoplasmic reticulum (ER) membrane. Only two protein subunits of the SRP, Srp54p and Sec65p, and the RNA subunit, scR1, were previously known in the yeast Saccharomyces cerevisiae. Purification of yeast SRP by immunoaffinity chromatography revealed five additional proteins. Amino acid sequencing and cloning of the genes encoding four of these proteins demonstrated that the yeast SRP contains homologs (termed Srp14p, Srp68p and Srp72p) of the SRP14, SRP68 and SRP72 subunits found in mammalian SRP. The yeast SRP also contains a 21 kDa protein (termed Srp21p) that is not homologous to any protein in mammalian SRP. An additional 7 kDa protein may correspond to the mammalian SRP9. Disruption of any one of the four genes encoding the newly identified SRP proteins results in slow cell growth and inefficient protein translocation across the ER membrane. These phenotypes are indistinguishable from those resulting from the disruption of genes encoding SRP components identified previously. These data indicate that a lack of any of the analyzed SRP components results in loss of SRP function. ScR1 RNA and SRP proteins are at reduced levels in cells lacking any one of the newly identified proteins. In contrast, SRP components are present at near wild type levels and SRP subparticles are present in cells lacking either Srp54p or Sec65p. Thus Srp14p, Srp21p, Srp68p and Srp72p, but not Sec65p or Srp54p, are required for stable expression of the yeast SRP.

Positive illusions and well-being revisited: separating fact from fiction

In 1988, we published an article that challenged the notion that accurate perceptions of self and the world are essential for mental health (Taylor & Brown, 1988). We argued instead that people's perceptions in these domains are positively biased and that these positive illusions promote psychological well-being. In the current article, we review our theoretical model, correct certain misconceptions in its empirical application, and address the criticisms made by Colvin and Block.

Familial predisposition to recurrent mutations causing Huntington's disease: genetic risk to sibs of sporadic cases

Huntington's disease (HD) is associated with expansion of a CAG repeat in a new gene. We have recently defined a premutation in a paternal allele of 30 to 38 CAG repeats in the HD gene which is greater than that seen in the general population (< 30 repeats) but below the range seen in patients with HD (> 38). These intermediate alleles are unstable during transmission through the germline and in sporadic cases expand to the full mutation associated with the clinical phenotype of HD. Here we have analysed three new mutation families where, in each, the proband and at least one sib have CAG sizes in the HD range. In one of these families, two sibs with expanded CAG repeats are both clinically affected with HD, thus presenting a pseudorecessive pattern of inheritance. In all three families the parental intermediate allele has expanded in more than one offspring, thus showing a previously unrecognised risk of inheriting HD to sibs of sporadic cases of HD.

Pharmacological activity of VUF 9153, an isothiourea histamine H3 receptor antagonist

The pharmacological activity of the histamine H3 receptor antagonist VUF 9153 (S-[3-(4(5)-imidazolyl)]propyl-N-(4-chlorobenzyl)isothiourea) has been investigated in vitro and in vivo. VUF 9153 displaced [3H]N alpha-methylhistamine binding to rat cortex/hippocampal membranes (pKi = 9.77 +/- 0.03) and antagonised the inhibitory responses to (R)-alpha-methylhistamine against electrical field stimulation in the isolated longitudinal smooth muscle preparation of guinea-pig ileum (pKB = 9.95 +/- 0.07). In these assays, VUF 9153 was 10-50-fold more potent than the prototype H3 receptor antagonist thioperamide. VUF 9153 showed no or very weak activity in in vitro functional assays for histamine H1 or H2 receptors. Systemic administration of VUF 9153 (s.c. or p.o.) dose-dependently inhibited the ex vivo binding of [3H]N alpha-methylhistamine to rat cortex/hippocampal membranes and dipsogenic responses induced by (R)-alpha-methylhistamine. Calculation of ED50 values, at the 1 h pretreatment time used, revealed that VUF 9153 administered s.c. or p.o., was approximately 2-fold weaker than thioperamide. These data indicate that, like thioperamide, VUF 9153 is a potent and selective antagonist for histamine H3 receptors in vitro, possesses the ability to penetrate the blood-brain barrier to access central H3 receptors and can inhibit H3 receptor-mediated functional responses in vivo.

Adolescents' risky behavior and mass media use

OBJECTIVE

To understand better the relationship between adolescents' use of the mass media (including television, radio, and magazines) and their risky or unhealthy behaviors.

DESIGN

Secondary data analysis of a 1987 in-home survey of 2760 randomly selected 14- to 16-year-old adolescents in 10 urban areas in the southeastern United States.

MEASUREMENT

The extent of participation in eight potentially risky behaviors (sexual intercourse, drinking, smoking cigarettes, smoking marijuana, cheating, stealing, cutting class, and driving a car without permission) and the use of a variety of mass media.

RESULTS

Adolescents who had engaged in more risky behaviors listened to radio and watched music videos and movies on television more frequently than those who had engaged in fewer risky behaviors, regardless of race, gender, or parents' education. White male adolescents who reported engaging in five or more risky behaviors were most likely to name a heavy metal music group as their favorite. Adolescents reported reading a wide diversity of magazines, and most reported reading at least one of a few selected magazines. Sports and music magazines were most likely to be read by adolescents who had engaged in many risky behaviors.

CONCLUSIONS

Mass media health promotion efforts could more specifically target adolescents who are engaging in multiple risky behaviors.

Exercise maintenance of persons with arthritis after participation in a class experience

This study investigated factors related to an initial exercise experience to explain exercise maintenance in 120 adults with rheumatoid arthritis or osteoarthritis. Integral secondary analysis was used to incorporate data from a prospective, controlled trial of exercise (Minor et al.: Arthritis Rheum 32:1396, 1989) with data collected at 18 months follow-up. The dependent variable was self-directed exercise (min/wk) reported at 3, 9, and 18 or more months after exercise class participation. Predictor variables included physical, psychosocial, disease, and programmatic factors. The all possible regressions search procedure resulted in three explanatory models (p = .0001). At 3 months the model (R2 = .45) included initial aerobic capacity, depression, and anxiety; and changes in depression and social activity. The 9-month model (R2 = .35) consisted of initial anxiety and physical activity, change in depression, support of friends for exercise, and exercise behavior at prior assessment. At 18 or more months (R2 = .42), model variables were initial aerobic capacity, change in pain, and exercise behavior at the two prior assessments. Neither disease nor program factors appeared as significant. This limited study indicates that factors associated with exercise behavior in this sample are similar to those in the general population; explanatory factors change over time, and changes ascribed to a trial behavior may influence subsequent decision making.

Self-esteem, mood, and self-evaluation: changes in mood and the way you see you

Three studies found that self-esteem moderates the relation between mood and self-evaluation. In Study 1, a standard mood-induction procedure was used to induce positive, negative, or neutral moods in low self-esteem (LSE) Ss and high self-esteem Ss. Afterward, Ss evaluated their specific qualities and characteristics (e.g., How smart are you? How kind are you?). Both self-esteem groups evaluated themselves favorably in a positive mood, but LSE Ss were more apt to lower their self-evaluations in a negative mood. Study 2 found a similar, though weaker pattern using a noncognitive, musical mood induction; Study 3 found that these effects occur with variations in naturally occurring mood over a 6-week period. The authors suggest that the tendency for LSE people to respond to negative moods with self-depreciation contributes to psychological distress.

Transscleral neodymium:YAG cyclophotocoagulation: comparison of 180-degree and 360-degree initial treatments

In order to help clarify how much Neodymium:YAG transscleral cyclophotocoagulation (Nd:YAG CPC) treatment should be given to maximize effectiveness and minimize complications in the treatment of refractory glaucomas, we retrospectively reviewed and compared the results achieved with an initial 180-degree noncontact Nd:YAG CPC treatment with those achieved with an initial 360-degree treatment. Forty-five patients were in the 180-degree group and 21 in the 360-degree group. Mean follow up after the first Nd:YAG CPC treatment was 10.2 +/- 7.5 months. The average pretreatment intraocular pressure (IOP) in the 180-degree group was 33.5 mm Hg. After one treatment, IOP in these patients dropped an average of 8.4 mm Hg and was controlled successfully (5 to 22 mm Hg) in 14 (31%). After a mean of 2.0 treatments, IOP in these patients dropped an average of 15.3 mm Hg, and successful IOP control was ultimately achieved in 35 (78%). The average pretreatment IOP in the 360-degree group was 41.8 mm Hg. After one treatment, IOP in these patients dropped an average of 19.4 mm Hg and was controlled successfully in 11 (52%). After a mean of 1.3 treatments, IOP in these patients dropped an average of 20.7 mm Hg, and successful IOP control was ultimately achieved in 13 (62%). Our study suggests that repeated 180-degree treatments can be successful. However, because we found that IOP was controlled more rapidly with fewer major complications in the 360-degree group, the risk-to-benefit ratio may be better for initial 360-degree treatment.

Self-esteem, mood, and self-evaluation: changes in mood and the way you see you

Three studies found that self-esteem moderates the relation between mood and self-evaluation. In Study 1, a standard mood-induction procedure was used to induce positive, negative, or neutral moods in low self-esteem (LSE) Ss and high self-esteem Ss. Afterward, Ss evaluated their specific qualities and characteristics (e.g., How smart are you? How kind are you?). Both self-esteem groups evaluated themselves favorably in a positive mood, but LSE Ss were more apt to lower their self-evaluations in a negative mood. Study 2 found a similar, though weaker pattern using a noncognitive, musical mood induction; Study 3 found that these effects occur with variations in naturally occurring mood over a 6-week period. The authors suggest that the tendency for LSE people to respond to negative moods with self-depreciation contributes to psychological distress.