The domain-variant indirect association between electrophysiological response to reward and ADHD presentations is moderated by dopaminergic polymorphisms.

BACKGROUND: Understanding the etiopathogenesis of attention-deficit/hyperactivity disorder (ADHD) may necessitate decomposition of the heterogeneous clinical phenotype into more homogeneous intermediate phenotypes. Reinforcement sensitivity is a promising candidate, but the exact nature of the ADHD-reward relation - including how, for whom, and to which ADHD dimensions atypicalities in reward processing are relevant - is equivocal. METHODS: Aims were to examine, in a carefully phenotyped sample of adolescents (N = 305; Mage = 15.30 years, SD = 1.07; 39.7% girls), whether functional dopaminergic polymorphisms implicated in both reward processing and ADHD (1) are differentially associated with event-related potentials (ERPs) of reward anticipation at distinct levels of ADHD risk (nno risk = 174, nat-risk = 131, ndiagnosed = 83); and (2) moderate the indirect effect of dispositional affectivity on the association between ERPs and ADHD domains. RESULTS: In adolescents at-risk for or with ADHD, carrying a hypodopaminergic allele was associated with enhanced ERPs of attention allocation to cue and attenuated ERPs of anticipatory attention to feedback. No associations were observed in adolescents not at-risk for or without ADHD. Controlling for age and sex, both the negative indirect effect of positive affectivity (PA) on the association between ERPs and inattention and the positive indirect effect of PA on the association between ERPs and hyperactivity/impulsivity were supported only for those with high activity dopamine transporter (DAT) alleles. CONCLUSIONS: Reward and affective processing are promising intermediate phenotypes relevant to disentangling ADHD developmental pathways. Consistent with developmental multifinality, through the successive effects of reward anticipation and positive affectivity, functional dopaminergic variants may confer protection against inattention or risk for hyperactivity/impulsivity.

The Association Between Prenatal Maternal Stress and Adolescent Affective Outcomes is Mediated by Childhood Maltreatment and Adolescent Behavioral Inhibition System Sensitivity.

Prenatal maternal stress is linked to offspring outcomes; however, there is little research on adolescents, behavioral, transdiagnostic outcomes, or the mechanisms through which relations operate. We examined, in N = 268 adolescents (Mage = 15.31 years; SD = 1.063; 57.8% boys) whether prenatal maternal stress is associated with adolescent affective outcomes; whether this association is mediated, serially, by childhood home atmosphere and adolescent behavioral inhibition system (BIS) sensitivity; and whether mediational effects are moderated by adolescent attention-deficit/hyperactivity disorder or maternal internalizing symptomology. Prenatal maternal daily stress and major life events were associated with adolescent outcomes through childhood negative atmosphere/neglect and BIS sensitivity, with no evidence of moderation. Results have implications regarding the effect of prenatal maternal stress on offspring outcomes and regarding corresponding sensitive periods.

Effect of short-term feeding duration of diets containing commercial whole-cell yeast or yeast subcomponents on immune function and disease resistance in channel catfish, Ictalurus punctatus.

Juvenile channel catfish, Ictalurus punctatus, were fed diets supplemented with yeast or yeast subcomponents (YYS) as commercial preparations of ß-glucan (MacroGard(®) and Betagard A(®)), mannan oligosaccharide (Bio-Mos(®) Aqua Grade), or whole-cell Saccharomyces cerevisiae (Levucell SB20(®)) at the manufacturers' recommended levels. Fish were fed experimental diets for 1 or 2 weeks prior to disease challenge (pre-challenge feeding periods) and sampled at the end of each feeding period to measure haematological and immune parameters and to determine the effects of dietary YYS on resistance to Edwardsiella ictaluri, the causative agent of enteric septicaemia disease (ESC). Feeding of experimental diets continued for 3 weeks post-challenge. In channel catfish fed diets supplemented with MacroGard(®), Betagard A(®), or Levucell SB20(®), survival in the 1 week pre-challenge feeding group and antibody titres in the 2 week feeding group were significantly higher post-E. ictaluri challenge in relation to catfish fed with the control diet. In fish fed these same three diets, survival to ESC was significantly higher after 1 week vs. 2 weeks feeding, while the antibody response was significantly higher after 2 weeks vs. 1 week. Lysozyme activity was also higher in the 1 week feeding group, but the increased activity was unrelated to diet. Feeding YYS-supplemented diets for a shorter duration of 1 week prior to challenge may prove beneficial in increasing resistance to ESC in channel catfish. However, we cannot discount that feeding YYS diets during the recovery period may have contributed to 'glucan overload' and reduced survival in the 2 week feeding group.

Effect of dietary alpha-tocopherol + ascorbic acid, selenium, and iron on oxidative stress in sub-yearling Chinook salmon (Oncorhynchus tshawytscha Walbaum).

A three-variable central composite design coupled with surface-response analysis was used to examine the effects of dietary alpha-tocopherol + ascorbic acid (TOCAA), selenium (Se), and iron (Fe) on indices of oxidative stress in juvenile spring Chinook salmon. Each dietary factor was tested at five levels for a total of fifteen dietary combinations (diets). Oxidative damage in liver and kidney (lipid peroxidation, protein carbonyls) and erythrocytes (erythrocyte resistance to peroxidative lysis, ERPL) was determined after feeding experimental diets for 16 (early December) and 28 (early March) weeks. Only TOCAA influenced oxidative stress in this study, with most measures of oxidative damage decreasing (liver lipid peroxidation in December and March; ERPL in December; liver protein carbonyl in March) with increasing levels of TOCAA. We also observed a TOCAA-stimulated increase in susceptibility of erythrocytes to peroxidative lysis in March at the highest levels of TOCAA. The data suggest that under most circumstances a progressive decrease in oxidative stress occurs as dietary TOCAA increases, but higher TOCAA concentrations can stimulate oxidative damage in some situations. Higher levels of TOCAA in the diet were required in March than in December to achieve comparable levels of protection against oxidative damage, which may have been due to physiological changes associated with the parr-smolt transformation. Erythrocytes appeared to be more sensitive to variation in dietary levels of TOCAA than liver and kidney tissues. Using the March ERPL assay results as a baseline, a TOCAA level of approximately 350-600 mg/kg diet would provide adequate protection against lipid peroxidation under most circumstances in juvenile Chinook salmon.

Preliminary examination of oxidative stress in juvenile spring Chinook salmon Oncorhynchus tshawytscha of wild origin sampled from transport barges.

Migrating juvenile wild Chinook salmon Oncorhynchus tshawytscha, collected and loaded onto transport barges at Lower Granite Dam on the Snake River, were sampled from barges at John Day Dam, 348 km downstream, at 5 day intervals beginning in late April and ending in late May. An increase in lipid peroxidation and decrease in vitamin E in liver were observed from early to late in the barge transportation season. These changes seemed unrelated to changes in plasma cortisol or corresponding glucose levels, which declined from early to late in the season, or the concentration of n-3 highly unsaturated fatty acid (HUFA) concentrations in tissue but may be related to water temperature, which increased during the transport season, or other changes associated with the parr-smolt transformation.

Genetic fingerprinting of Flavobacterium columnare isolates from cultured fish.

AIMS: To evaluate the intraspecific diversity of the fish pathogen Flavobacterium columnare. METHODS AND RESULTS: Genetic variability among Fl. columnare isolates was characterized using restriction fragment length polymorphism analysis of the 16S rDNA gene, intergenic spacer region (ISR) sequencing, and amplified fragment length polymorphism (AFLP) fingerprinting. Thirty Fl. columnare cultures isolated from different fish species and geographical origins as well as reference strains were included in the study. Fifteen isolates belonged to genomovar I while eleven were ascribed to genomovar II. Analysis of the ISR sequence confirmed the genetic differences between both genomovars but revealed a higher diversity among genomovar I isolates. The maximum resolution was provided by AFLP fingerprinting, as up to 22 AFLP profiles could be defined within the species. CONCLUSIONS: We confirmed the division of Fl. columnare isolates from cultured fish into different genogroups. We showed that both genomovars I and II are present in channel catfish from the US. We described a unique genetic group represented by four Fl. columnare isolates from tilapia in Brazil which appears to be related to both genomovars. We were able to further subdivide the species by analysing the ISR. Finally, the use of AFLP allowed us to fingerprint the species at clone level without losing the higher genetic hierarchy of genomovar division. SIGNIFICANCE AND IMPACT OF THE STUDY: This paper reports on an extensive assessment of the use of molecular tools for the study of the epidemiology of the fish pathogen Fl. columnare.

Managing organizational challenge and change: closing an inpatient unit.

The effects of a turbulent health care delivery market have impacted the day-to-day reality of acute care hospitals. One effect is that the supply of acute care hospital beds currently exceeds the demand, a trend that is expected to continue to the year 2000 and beyond. Nursing administrators at St. Marys Hospital Medical Center made the decision to close an inpatient unit in order to better match acute care bed supply to existing demand. Decision support for closure, organizational change, and lessons learned from the closure process are discussed.