Non-additive effects of genotypic diversity increase floral abundance and abundance of floral visitors.

BACKGROUND: In the emerging field of community and ecosystem genetics, genetic variation and diversity in dominant plant species have been shown to play fundamental roles in maintaining biodiversity and ecosystem function. However, the importance of intraspecific genetic variation and diversity to floral abundance and pollinator visitation has received little attention. METHODOLOGY/PRINCIPAL FINDINGS: Using an experimental common garden that manipulated genotypic diversity (the number of distinct genotypes per plot) of Solidago altissima, we document that genotypic diversity of a dominant plant can indirectly influence flower visitor abundance. Across two years, we found that 1) plant genotype explained 45% and 92% of the variation in flower visitor abundance in 2007 and 2008, respectively; and 2) plant genotypic diversity had a positive and non-additive effect on floral abundance and the abundance of flower visitors, as plots established with multiple genotypes produced 25% more flowers and received 45% more flower visits than would be expected under an additive model. CONCLUSIONS/SIGNIFICANCE: These results provide evidence that declines in genotypic diversity may be an important but little considered factor for understanding plant-pollinator dynamics, with implications for the global decline in pollinators due to reduced plant diversity in both agricultural and natural ecosystems.

An investigation of psychopathology in nonreferred suicidal and nonsuicidal adolescents.

This investigation examined self-reported psychopathology in a school-based sample of 456 suicidal and nonsuicidal adolescents. The sample consisted of four groups: three at-risk for suicidal behavior based on current suicidal ideation as assessed by the Suicidal Ideation Questionnaire (SIQ; Reynolds, 1988), past suicide attempts, or both; and one nonsuicidal comparison group. Psychopathology was examined using ten scales from the Adolescent Psychopathology Scale (APS; Reynolds, 1998a) including: Major Depression, Conduct Disorder, Substance Abuse, Schizophrenia, Adjustment Disorder, Anorexia Nervosa, Borderline Personality Disorder, Obsessive-Compulsive Personality Disorder, Schizotypal Personality Disorder, and Avoidant Personality Disorder. Analyses were conducted separately for males and females using a MANOVA design that examined psychopathology severity among the four groups. Adolescents who engaged in past or current suicidal behavior had higher psychopathology severity scores compared to their nonsuicidal peers. Males with current suicidal thoughts who had attempted suicide had the highest levels of psychopathology severity compared to males in the other three groups. Females with a past suicide attempt or current suicidal ideation had higher psychopathology severity scores compared to nonsuicidal females. Results show greater psychopathology in school-based adolescents who have engaged in past and/or current suicidal behavior. The need for clinicians and mental health professionals working with at-risk youth to focus on concurrent psychopathology along with suicidal behavior is discussed.

Exposure to violence in young inner-city adolescents: relationships with suicidal ideation, depression, and PTSD symptomatology.

This study examined the relationship of exposure to violence to suicidal ideation, depression, and post-traumatic stress disorder (PTSD) symptomatology in 94 young adolescents from an inner-city school. Participants completed self-report measures of the Reynolds Adolescent Depression Scale, the Suicidal Ideation Questionnaire--Junior, Adolescent Psychopathology Scale--Posttraumatic Stress Disorder Subscale, and the Exposure to Violence Questionnaire. Using a hierarchical multiple regression design, exposure to violence demonstrated a unique relationship with PTSD symptomatology. Specifically, the relationship between violence exposure and PTSD symptomatology remained significant after controlling for depression and suicidal ideation severity. Controlling for PTSD symptomatology resulted in nonsignificant relationships between violence exposure and depression and suicidal ideation in adolescents. Additional analyses suggest that PTSD functions as a mediating variable between exposure to violence and depression and suicidal ideation. The implication of these results and suggestions for future research are discussed.

A longitudinal investigation of depression, hopelessness, social support, and major and minor life events and their relation to suicidal ideation in adolescents.

The longitudinal relationship of psychological and social-environmental factors with adolescent suicidal ideation over a 1-year-period was examined in a sample of 374 high school students. Students were assessed twice over a 1-year period with measures of depression, hopelessness, major negative life events, daily hassles, social support, and suicidal ideation. At the initial assessment, daily hassles and negative life events for males and social support and depression for females were significant factors related to suicidal ideation levels 1 year later. Changes in depression and hopelessness were significantly related to changes in suicidal ideation over the 1 year interval for males and females. Differences found between males and females in the relationship of psychological and social-environmental variables with suicidal ideation supports the need to examine gender specific relationships when conducting research on suicidal behavior in adolescents.

Automated routine HLA-B27 typing by flow cytometry.

An increasing demand for HLA-B27 typing as one of the tests used in the diagnosis of ankylosing spondylitis had led us to develop a rapid, automated, flow cytometric assay using whole blood and an HLA-B27 specific monoclonal antibody FD705. This article shows the data from 2093 samples tested during a 2 year period of routine HLA-B27 typing. 21.6% were clearly HLA-B27 positive whilst 73.2% were HLA-B27 negative, the remaining 5.2% required further testing before assignment of HLA-B27 status. Additional work was carried out on blood samples from individuals positive for the newly described subtype HLA-B2708.

Evaluation of the flow cytometric crossmatch. Preliminary results of a multicenter study.

The flow cytometric crossmatch is a technique that is increasingly being used by clinical transplant laboratories. In this multicenter study by the British Society for Histocompatibility and Immunogenetics Flow Cytometry Group, a series of crossmatches were carried out to determine whether different centers obtained same results when performing the same crossmatch. There was greater than 80% agreement among participating laboratories on the results of 35/54 tests. There was no clear agreement in the remaining 20 cases. Quantitative analysis, estimating the number of cell-bound fluorescein molecules, demonstrated that differences in the criteria used by each center to define a positive crossmatch were responsible for some discordant results. When applied, definition of positivity based on the molecules of fluorescein increased concordance from 57.5% to 81.4%.l. These results suggest that a criterion for the interpretation of results based on quantitative analysis of bound antibody may be more reliable than methods in current routine use.

Computerized and clinician assessment of depression and anxiety: respondent evaluation and satisfaction.

This investigation examined differences in subjects' satisfaction and reaction to computer- and clinician-administered versions of the Hamilton Depression and Anxiety Rating Scales in outpatients with affective disorders (n = 121), anxiety disorders (n = 52), other psychiatric disorders (n = 7), and adults without psychiatric disorders (n = 76). Subjects' reactions to clinician- and computer-administered interviews were similar in the areas of overall comfort level and ease in answering questions. Clinicians were rated more positively with regard to determining how subjects really felt, sensitivity to their needs, and asking questions specific to their feelings. Subjects felt less embarrassed giving information to the computer. We found psychiatric subjects to prefer the clinician-administered interview, whereas nonpsychiatric subjects indicated no preference.

Automated HLA-B27 testing using the FACSPrep/FACScan system.

Tissue typing can help in the diagnosis of the seronegative arthropathy ankylosing spondylitis. Using an automatic sample preparation system and flow cytometry (FACSPrep/FACScan) we have developed a test for HLA-B27 screening using whole blood which is both rapid, reproducible, and permits simultaneous screening of large numbers of samples. We have used both indirect (248 cases) and direct (126 cases) monoclonal antibody staining techniques. Results were assessed using median channel shift (CS) from the negative control and relative fluorescence intensity. There is known cross-reactivity between HLA-B27 and HLA-B7 with the monoclonal antibody (MoAb) HLA-ABC-m3. Using this antibody and indirect staining, HLA-B7 samples had a significantly lower CS value than HLA-B27 samples. In 60% of these cases there was a clear distinction between HLA-B27 and HLA-B7. All HLA-B27 and HLA-B7 negative samples had a CS of 0 (P < 0.001). Using direct dual staining with CD3 and HLA-B27, all HLA-B27 and HLA-B7 negative samples had a low CS value (15 maximum), HLA-B7 samples had an intermediate CS value (20-85), and HLA-B27 samples had the highest CS values (70 upward). This system permits large scale rapid negative screening of samples with the elimination of over 60% as negatives (CS < 15). Limitations as a definitive test for HLA-B27 are due to MoAb cross-reactivity with HLA-B7 which necessitates other confirmatory techniques. The substitution of the HLA-ABC-m3 with the recently available HLA-B27 specific MoAb FD705 would substantially increase the value of this technique for routine HLA-B27 typing.

A simple technique for the determination of kappa and lambda immunoglobulin light chain expression by B cells in whole blood.

This article describes the development of a simple technique by which the numbers of surface immunoglobulin expressing cells can be analysed by dual fluorescence flow cytometry in samples of whole blood. We have compared the results obtained using this procedure with those obtained using samples prepared by traditional density gradient centrifugation, and demonstrate an excellent correlation between the two techniques. The method is applicable both to blood samples from normal individuals and from patients with B cell malignancies such as B-CLL and B-NHL. We have also confirmed previous findings that density gradient centrifugation may preferentially deplete certain lymphocyte subsets. This technique offers the following advantages: (i) it is rapid, (ii) it is accurate, (iii) it is reliable, (iv) it is useful in cases of lymphopenia, and (v) it requires only a small volume of blood. It is likely to be applicable to other situations in which the presence of serum factors interfere with antibody staining in whole blood.

T-cell receptor variable (V) gene usage by lymphoid populations in T-cell lymphoma.

A panel of monoclonal antibodies specific for TcR V gene families was used to study TcR V region expression in 28 cases of malignant and reactive T-cell expansions including four cases of mixed cellularity Hodgkin's disease (HD) and five reactive cases. TcR V beta 5 gene products were represented in three cases of lymphoblastic malignancy (V beta 5.1, V beta 5.2) and two cases of peripheral T-cell lymphoma (PTCL) (V beta 5.1). In the PTCL cases, the expanded family was found in the absence of clonal TcR gene rearrangements and in one of these cases with Ig JH and Ck clonal gene rearrangements consistent with the presence of a phenotypically and histologically undetectable clonal B-cell population. In a third PTCL case not investigated for genotype, the TCR V alpha 12 family was overrepresented. Expanded TcR V alpha 2 and V beta 5.1 families were identified in HD and V beta 8 and V beta 5.2/V beta 5.3 families in a reactive lymph node and CD3 and CD8-positive blood lymphocytosis respectively. Further study of PTCL and related entities are needed to establish whether expanded TcR families are common in those cases that fail to exhibit clonal TcR gene rearrangement.

Lack of correlation between IgG T-lymphocyte flow cytometric crossmatches with primary renal allograft outcome.

The flow cytometric crossmatch (FCXM) has been reported to be more sensitive and capable of detecting very low levels of antibodies than the normally used complement dependent cytotoxicity test. We studied both the two colour IgG T cell FCXM and CDC-XM in 146 renal allograft recipients, 111 primary and 35 regrafts, of which 26% (29/111) of 1st and 20% (7/35) of regrafts had a positive FCXM. There was no overall correlation between the FCXM results and early graft outcome in primary renal allografts. The FCXM did not appear to have any advantage over the CDC-XM in predicting graft outcome in unsensitized first grafts. In the small number of regrafts studied, a positive FCXM was associated with a higher degree of graft failure. FCXM can exhibit false negative results if sera are used solely neat although these prozone phenomena do not influence subsequent graft outcome.

Psychometric characteristics of the Adult Suicidal Ideation Questionnaire in college students.

There is a growing concern for identifying individuals at risk for suicidal behaviors. Suicidal ideation, that is, the thoughts and cognitions one has about suicidal behaviors and intent, may be considered a primary marker for the risk of more serious suicidal behaviors. This investigation examined the reliability and validity of the Adult Suicidal Ideation Questionnaire (ASIQ; Reynolds, in press-a), a 25-item self-report suicidal ideation measure designed for adults. Subjects were 474 college students from two Midwestern universities. Results indicated high internal consistency (r alpha = .97) and test-retest (rtt = .86) reliability of the ASIQ with college students. Significant correlations (rs = .38 to .60) were found with measures of depression, hopelessness, anxiety, and self-esteem. For the total sample, a multiple correlation of .67 was found between the ASIQ, the independent variables just noted, and history of prior suicide attempt. Factor analysis of the ASIQ produced a four-factor solution. Psychometric support for the utilization of the ASIQ in clinical and research settings is presented and discussed.

Reliability of children's reports of depressive symptomatology.

The use of self-report measures for the assessment of depression in children has gained wide popularity as a component in the evaluation of children's mental health and well-being. However, the extent to which children are reliable and consistent reporters of their depressive symptoms is sometimes called into question. This study examined the test-retest reliability of children's reports of depressive symptomatology on the Reynolds Child Depression Scale (RCDS; Reynolds, 1989a). The sample consisted of 220 children, in grades 3 through 6, representing a cross-section of ethnic groups. Children were tested twice, with a 4-week interval between testings. Results showed a high degree of stability in children's responses to the RCDS, with a test-retest reliability coefficient of .85 for the total sample, and a mean difference between testings of less than 2 points. Test-retest reliability coefficients were also computed for males and females, for each grade, and for white, black, Hispanic, and Asian children. Overall, the results lend strong support for the reliability and stability of children's self-reported depressive symptomatology as assessed by the RCDS.

Assessment of adolescents' learned helplessness in achievement situations.

Three studies are reported that describe the development, reliability, and initial validation of the Mastery Orientation Inventory (MOI; Reynolds & Miller, in press) as a measure of generalized learned helplessness in adolescents. In Study 1, an initial version of 50 items was administered to a sample of 112 adolescents. A revised 40-item scale with an internal consistency reliability of .94 was then constructed, which correlated significantly with measures of locus of control and depression. Study 2 involved the administration of the 40-item MOI to 645 adolescents. In this study, the reliability of the MOI was .92, and MOI scores were significantly correlated with subjects' depression scores and with self-reported grade point average. Factor analysis of the MOI items produced a strong first factor with high loadings for every item. In Study 3, the 112 subjects who participated in Study 1 were, 3 months later, readministered the MOI, locus of control, and depression measures. As an external criterion variable, 13 teachers provided global ratings of learned helpless/mastery-oriented behaviors for 99 of these subjects. The MOI demonstrated high internal consistency (r alpha = .95) and adequate test-retest (rtt = .77) reliability. Validity was supported by significant correlations between the MOI and the three criterion variables (/rs/ = .49-.58). The results of these investigations provide initial support for the reliability and validity of the MOI as a measure of learned helplessness.

Assessment of depression in persons with mental retardation.

The psychometric characteristics of the Self-Report Depression Questionnaire (SRDQ, Reynolds, in press a), a 32-item self-report measure of depressive symptomatology in persons with mental retardation, were examined. The SRDQ was orally administered to 89 adults living in community-based settings. An internal consistency reliability coefficient of .90, and an 11-week test-retest reliability of .63 were obtained. Criterion-related validity was demonstrated by a high degree of relationship, r = .67, p less than .001, between the SRDQ and individual clinical interviews using the Hamilton Depression Rating Scale. An exploratory factor analysis of the SRDQ items was also presented.

A comparison of the relative efficacy of self-control therapy and a behavioral problem-solving therapy for depression in children.

Twenty-nine children 9 to 12 years old who were identified as moderately to severely depressed using the Children's Depression Inventory were randomly assigned to either a self-control, behavioral problem-solving, or waiting list condition. The self-control treatment focused on teaching children self-management skills. The behavioral problem-solving therapy consisted of education, self-monitoring of pleasant events, and group problem solving directed toward improving social behavior. Subjects were assessed pre- and posttreatment and at 8-week follow-up with multiple assessment procedures and from multiple perspectives. At posttreatment, subjects in both active treatments reported significant improvement on self-report and interview measures of depression while subjects in the waiting list condition reported minimal change. Results were maintained at follow-up. The general success of the experimental treatments was discussed and recommendations for further treatment components were provided.

National standardization of the Auditory Discrimination Test: normative and reliability results.

The Auditory Discrimination Test (ADT), which consists of two alternate forms (Forms 1A and 2A), has been used extensively in clinical, educational, and research settings for nearly 30 years. Until now, two major problems with the clinical and educational use of the ADT have been the lack of representative norms, and the somewhat restricted age range of the test. This article reports on a national standardization of the ADT, and an extension of this test downward for use with four year old children. The sample included over 1.800 children from public and private elementary and preschool settings who were selected from over 30 states across the country. The sample was stratified on the basis of geographic region, age, sex, ethnic background, parent's occupation, and community size. Results indicated developmental differences in auditory discrimination as assessed by the ADT, substantiating the utility of age level norms. In addition, internal consistency reliability was computed for all age levels on the ADT. A median reliability of.78 was found for ADT Form 1A, and.81 for ADT Form 2A, with higher reliabilities found at the younger ages. Overall, the results of this investigation suggest that the ADT is a useful measure of auditory discrimination in young children. Furthermore, the development of national, stratified norms provides renewed utility for the application of test results in norm-referenced decision situations.

Self-control in children: a multimethod examination of treatment outcome measures.

This investigation consisted of a multimethod evaluation of treatment outcome measures that have been developed to assess self-control in children. Subjects were 132 children from the fourth, fifth, and sixth grades. Each child's homeroom teacher and one other classroom teacher independently completed the Self-Control Rating Scale (SCRS), the Teacher's Self-Control Rating Scale (TSCRS), and the 10-item Conners Teacher Rating Scale (TRS). Parents of 41 children completed the Teacher's Self-Control Rating Scale and the Conners Teacher Rating Scale. Children completed the Children's Perceived Self-Control Scale (CPSC) and were administered the Matching Familiar Figure Test (MFF). Results showed high internal consistency reliability for the TSCRS, SCRS, TRS, and MFF latency scores. CPSCS and MFF error scores demonstrated low reliability (r alpha's = .58 and .61, respectively). Interrater reliability between teachers was considered acceptable for the TSCRS but not for the SCRS and TRS. Correlations between teacher and parent ratings on the TSCRS and TRS were low (r's = .37 to .50). Correlations between children's latency scores on the MFF and teachers and parent ratings were very low, r's = .01 to .19, as was the correlation with children's self-ratings on the CPSCS (r = .07). Correlations between rating scales and MFF error scores also were low. The findings suggest that considerable construct confusion does exist between measures designed to assess self-control and impulsivity in children.