Orbitofrontal cortex reflects changes in response-outcome contingencies during probabilistic reversal learning.

In a continuously changing environment, in which behavioral outcomes are rarely certain, animals must be able to learn to integrate feedback from their choices over time and adapt to changing reward contingencies to maintain flexible behavior. The orbitofrontal region of prefrontal cortex (OFC) has been widely implicated as playing a role in the ability to flexibly control behavior. We used a probabilistic reversal learning task to measure rats' behavioral flexibility and its neural basis in the activity of single neurons in OFC. In this task, one lever, designated as 'correct', was rewarded at a high probability (80%) and a second, spatially distinct lever, designated as 'incorrect', was rewarded at a low probability (20%). Once rats reached a learning criterion for reliably selecting the correct lever, reward contingencies of the two levers were switched, and daily sessions were conducted until rats reliably selected the new correct lever. All rats performed the initial Acquisition and subsequent Reversal successfully, with more sessions needed to learn the Reversal. OFC neurons were recorded during five behavioral sessions spanning Acquisition and Reversal learning. The dominant pattern of neural responding in OFC, identified by principal component analysis of the population of neurons recorded, was modulated by reward outcome across behavioral sessions. Generally, activity was higher following rewarded choices than unrewarded. However, there was a correlation between reduced responses to reward following incorrect choices and the establishment of the preference for the correct lever. These results show how signaling by individual OFC neurons may participate in the flexible adaptation of behavior under changing reward contingencies.

Assays for genetic dissection of septin filament assembly in yeast, from de novo folding through polymerization.

In Saccharomyces cerevisiae, septin mutations have severe effects on colony-forming ability, particularly at high temperatures, allowing the full variety of genetic tools available in this model organism to be applied to the study of septin biology. Although many details of septin function remain unknown, one can exploit a small number of easily scored phenotypes-proliferation capacity, cell morphology, septin localization, and septin ring integrity-as sensitive readouts of properly assembled septin filaments. Accordingly, this chapter focuses on genetic approaches targeted toward understanding the molecular mechanisms of de novo septin folding, heterooligomerization, and polymerization into filaments. The same general methods can be used to interrogate septin function, although interpretation of results can be more complicated. As genetic-based methodologies are technically simple but particularly dependent on interpretation, here I focus on the logic underlying the most common interpretations of results using septin mutants.

Small molecule perturbations of septins.

Progress on the study of the molecular and cellular biology of septins would be greatly accelerated by the development of small molecules that directly inhibit higher-order septin assembly in vivo. By comparison, molecules like latrunculin, paclitaxil, benomyl, etc. allow researchers to acutely perturb the actin or tubulin cytoskeletal networks. Two small molecules, forchlorfenuron (FCF; N-(2-chloro-4pyridyl)-N-phenylurea) and 1-ethyl-3-(4-methoxyphenyl)-6-methylpyrimido[5,4-e][1,2,4]triazine-5,7-dione (PubChem CID 906558), have documented effects on septin localization and/or function, although for each molecule there is also strong evidence for off-target effects. In this chapter we provide a summary of ways to utilize FCF to alter higher-order septin assembly properties in living cells.

Dopamine D2/3 receptor antagonism reduces activity-based anorexia.

Anorexia nervosa (AN) is an eating disorder characterized by severe hypophagia and weight loss, and an intense fear of weight gain. Activity-based anorexia (ABA) refers to the weight loss, hypophagia and paradoxical hyperactivity that develops in rodents exposed to running wheels and restricted food access, and provides a model for aspects of AN. The atypical antipsychotic olanzapine was recently shown to reduce both AN symptoms and ABA. We examined which component of the complex pharmacological profile of olanzapine reduces ABA. Mice received 5-HT(2A/2C), 5-HT3, dopamine D1-like, D2, D3 or D2/3 antagonist treatment, and were assessed for food intake, body weight, wheel running and survival in ABA. D2/3 receptor antagonists eticlopride and amisulpride reduced weight loss and hypophagia, and increased survival during ABA. Furthermore, amisulpride produced larger reductions in weight loss and hypophagia than olanzapine. Treatment with either D3 receptor antagonist SB277011A or D2 receptor antagonist L-741,626 also increased survival. All the other treatments either had no effect or worsened ABA. Overall, selective antagonism of D2 and/or D3 receptors robustly reduces ABA. Studies investigating the mechanisms by which D2 and/or D3 receptors regulate ABA, and the efficacy for D2/3 and/or D3 antagonists to treat AN, are warranted.

Early postpartum pup preference is altered by gestational cocaine treatment: associations with infant cues and oxytocin expression in the MPOA.

Cross-fostering studies suggest cocaine-induced deficits in maternal behavior could be associated with altered behavior of offspring following prenatal cocaine-exposure. Neonatal vocalizations are an important offspring cue facilitating early interactions between dam and rodent pup offspring and have been shown to be altered following prenatal cocaine-exposure. It is unclear how variations in acoustic parameters of USVs impact maternal behavior and the mechanism(s) underlying these processes. The present study examined differences in cocaine-exposed and control rodent dam maternal preference of cocaine-exposed or untreated pups in a dual choice apparatus. Relationship of preference-like behavior with pup USVs and dam oxytocin expression was explored. Gestational cocaine-exposure interfered with preference-like behavior of dams on postpartum day 1 with cocaine-exposure associated with decreased time spent on the cocaine-exposed pup side compared to the control pup side, and decreases in preference-like behavior associated in part with decreased number of USVs being emitted by cocaine-exposed pups. On postpartum day 5, decreased oxytocin expression in the medial preoptic area was associated with altered preference-like behavior in cocaine-exposed dams, including frequency and latency to touch/sniff pups. Results indicate cocaine's effects on the mother-infant relationship is likely synergistic, in that cocaine influences mother and offspring both independently and concertedly and that variations within pup vocalizations and the oxytocin system may be potential mechanism(s) underlying this synergistic relationship during the postpartum period.

Intergenerational effects of cocaine on maternal aggressive behavior and brain oxytocin in rat dams.

Gestational cocaine treatment results in significantly increased maternal aggression towards an intruder by postpartum day six, while acute postpartum treatment dose dependently decreases maternal aggressive (MA) behavior. Both increased and decreased aggression in the cocaine-treated dams are correlated with either decreased or increased levels of oxytocin in the amygdala, respectively. The current study was an effort to determine whether the effect of gestational cocaine on maternal aggression is transient or would continue into the postpartum period; whether an intermittent cocaine treatment regimen, which incorporates gestational and postpartum intermittent cocaine treatment, would differ from chronic daily gestational treatment; and finally, whether next generation female offspring of cocaine-treated or control dams would have altered MA behavior and oxytocin system changes attributable to either prenatal drug exposure, rearing condition or both. We now report no increase in maternal aggression following chronic gestational treatment and significantly lower levels of aggression in intermittently treated dams on postpartum day eight, with no significant effects in either group on postpartum day 12. Young adult female offspring of the cocaine-treated and control dams, who reared their own natural litters and were tested on postpartum day eight for maternal aggression, had higher levels of maternal aggression towards an intruder attributable to both prenatal cocaine exposure and rearing condition. Higher aggression in cocaine-reared next generation dams was associated with lower levels of oxytocin in the amygdala. Intergenerational effects of cocaine were apparent with respect to aggression and oxytocin system changes.

Gestational ethanol and nicotine exposure: effects on maternal behavior, oxytocin, and offspring ethanol intake in the rat.

Alcohol consumption and smoking during pregnancy is common, despite the known adverse effects of these drugs on fetal development. Though studies on the effects of each drug separately are published, little is known about the effect of concurrent use of alcohol and nicotine in humans or in preclinical models. In this report, we examined the impact of continuous gestational exposure to both ethanol via liquid diet and nicotine via an osmotic minipump on maternal behavior, offspring ethanol intake, and oxytocin levels in a rat model. Dams were tested for the onset of maternal behavior with litters of unexposed surrogate pups and then killed to examine oxytocin levels within specific brain regions. Drug-exposed offspring reared by surrogate dams were tested for ethanol intake at either adolescence or adulthood, and oxytocin levels were measured in relevant brain regions after behavioral tests. Dams exhibited minor deficits in maternal care, which were associated with lower oxytocin levels in both the ventral tegmental and medial preoptic areas compared to control dams. Prenatal exposure altered sex-specific ethanol intake, with differential effects at adolescence and adulthood. Oxytocin system changes were also apparent in the ventral tegmental and medial preoptic regions of drug-exposed adolescent and adult offspring. These results suggest that dam treatment with ethanol and nicotine can somewhat negatively affect the early rearing environment, and that prenatal exposure to both of these drugs results in drinking behavior differing from what would be expected from either drug alone. Oxytocin's possible involvement in the mediation of these effects is highlighted.

Impact of gestational cocaine treatment or prenatal cocaine exposure on early postpartum oxytocin mRNA levels and receptor binding in the rat.

Prior research reported decreased oxytocin levels in specific brain regions correlated with disruptions in maternal care following gestational cocaine treatment in rats. Similarly, prenatal exposure to cocaine impaired subsequent maternal behavior in adulthood, but behavioral alterations were not associated with decreases in oxytocin levels in the same brain regions as were found in their cocaine-treated rat dams. To determine if other aspects of the oxytocin system are disrupted by cocaine treatment or prenatal exposure to cocaine during critical time points associated with maternal care, oxytocin mRNA transcription and receptor binding were examined on postpartum day two in relevant brain regions following gestational treatment with, or prenatal exposure to, either cocaine or saline. We hypothesized that oxytocin mRNA levels and receptor binding would be differentially affected by cocaine in the early postpartum period of dams and their offspring. Our findings indicate that gestational cocaine treatment resulted in significant increases in oxytocin mRNA levels in only the paraventricular nucleus of cocaine-treated dams, with almost significant increases in both generations in the supraoptic nucleus, but no significant effects of cocaine on receptor binding in either generation of dams. These findings indicate that in addition to oxytocin levels, cocaine treatment or prenatal exposure primarily affects oxytocin mRNA synthesis, with little effect on receptor binding in specific brain regions associated with maternal behavior in the early postpartum period of the rat.

Cocaine treatment alters oxytocin receptor binding but not mRNA production in postpartum rat dams.

Gestational cocaine treatment in rat dams results in decreased oxytocin (OT) levels, up-regulated oxytocin receptor (OTR) binding density and decreased receptor affinity in the whole amygdala, all concomitant with a significant increase in maternal aggression on postpartum day six. Rat dams with no gestational drug treatment that received an infusion of an OT antagonist directly into the central nucleus of the amygdala (CeA) exhibited similarly high levels of maternal aggression towards intruders. Additionally, studies indicate that decreased OT release from the hypothalamic division of the paraventricular nucleus (PVN) is coincident with heightened maternal aggression in rats. Thus, it appears that cocaine-induced alterations in OT system dynamics (levels, receptors, production, and/or release) may mediate heightened maternal aggression following cocaine treatment, but the exact mechanisms through which cocaine impacts the OT system have not yet been determined. Based on previous studies, we hypothesized that two likely mechanisms of cocaine's action would be, increased OTR binding specifically in the CeA, and decreased OT mRNA production in the PVN. Autoradiography and in situ hybridization assays were performed on targeted nuclei in brain regions of rat dams on postpartum day six, following gestational treatment twice daily with cocaine (15 mg/kg) or normal saline (1 ml/kg). We now report cocaine-induced reductions in OTR binding density in the ventromedial hypothalamus (VMH) and bed nucleus of the stria terminalis (BNST), but not the CeA. There was no significant change in OT mRNA production in the PVN following cocaine treatment.

The effects of dopaminergic/serotonergic reuptake inhibition on maternal behavior, maternal aggression, and oxytocin in the rat.

Studies using dopaminergic and serotonergic agonists or antagonists implicate involvement of these systems in various aspects of early maternal behavior and postpartum aggression towards an intruder in rats, both of which are associated with the presence of oxytocin in specific brain regions. It is unclear however, if or how long-term uptake inhibition of either neurotransmitter system alone or in combination, affects oxytocin system dynamics or maternal behavior/aggression. Pregnant women frequently take drugs (antidepressants, cocaine) that induce long-term reuptake inhibition of dopamine and/or serotonin, thus it is important to understand these effects on behavior and biochemistry. Rat dams were treated throughout gestation with amfonelic acid, fluoxetine, or a combination of both, to investigate effects of reuptake inhibition of dopamine and serotonin systems respectively, on maternal behavior, aggression and oxytocin. The more appetitive aspects of maternal behavior (nesting, licking, touching) and activity were increased by the low dose of amfonelic acid, high dose of fluoxetine, or the high dose combination more than other treatments. Aggression was decreased by amfonelic acid and somewhat increased by fluoxetine. Dopamine uptake inhibition appears to have a strong effect on hippocampal oxytocin levels, while receptor dynamics may be more strongly affected by serotonin uptake inhibition.

Reducing complications during hemodialysis using gradient ultrafiltration with gradient sodium dialysate.

The objective of this study was to determine if patient complications and nursing interventions during hemodialysis could be reduced using gradient ultrafiltration and gradient sodium dialysate. Twenty outpatients who had been on hemodialysis for at least 3 months, and using gradient sodium dialysate for at least 1 month, participated. Patients received either ultrafiltration at a constant hourly rate or gradient ultrafiltration, in which the ultrafiltration rate was set higher initially, then decreased step-wise mid-dialysis. Patients received each protocol for 3 months, using a randomized cross-over design. Both protocols used gradient sodium dialysate (150 mEq/L x 3 hrs, 140 mEq/L x 1 hr). There were significantly fewer complications and interventions using gradient ultrafiltration, as compared to constant ultrafiltration. No differences were found in interdialytic weight gain, intradialytic weight loss, or orthostatic blood pressure. These results indicate that gradient ultrafiltration combined with gradient sodium dialysate enhances patient well-being and reduces nursing interventions during hemodialysis.

Treatment products and approaches for phenylketonuria: improved palatability and flexibility demonstrate safety, efficacy and acceptance in US clinical trials.

A new amino acid formulation and a variety of treatment products incorporating it were evaluated for long-term safety, efficacy, and acceptance in 25 subjects with phenylketonuria over a period of 5 years. Palatability of the treatment was improved by reducing the required intake of amino acids, reformulating the mixture to have better taste, and providing vitamins and minerals as tablets. The hypotheses were that these strategies would improve compliance and metabolic control and maintain nutritional status in subjects. Compliance with treatment was determined from mean reported intakes (4-day diet records) and from mean 'received' intakes using receipts of treatment products actually shipped to individuals upon request. Mean amino acid intakes prescribed were significantly reduced from study entry to end, from 1.2 g/kg to 0.7 g/kg (p < 0.001). Reported intakes were similarly reduced from 1.3 g/kg to 0.7 g/kg (p < 0.001). While actually 'received' intakes of amino acid formula were also significantly reduced (p < 0.001), intakes by this measure were much lower than either prescribed or reported, 0.9 g/kg at entry and 0.4 g/kg at the end of the study, suggesting that acceptance of the treatment (usage of products), even when made more palatable, is below clinical expectations. In spite of these findings, mean serum proteins and minerals, height and weight were not significantly reduced during the study, supporting the safety of lowered intakes of amino acids and of nutritionally incomplete products. While the increase in mean serum phenylalanine concentration from 0.38 to 0.48 mmol/L was significant (p < 0.03), this mean rise of 0.1 mmol/L during a corresponding mean age increase of 4.2 years (from 6.9 to 11.1 years) is lower than in other recent reports from longitudinal studies of outcomes during this age range in subjects treated with traditional products. These data support the safety and efficacy of a more palatable and flexible approach to treatment.

Sense of time in children with ADHD: effects of duration, distraction, and stimulant medication.

A recent theory of ADHD predicts a deficiency in sense of time in the disorder. Two studies were conducted to test this prediction, and to evaluate the effects of interval duration, distraction, and stimulant medication on the reproductions of temporal durations in children with ADHD. Study I: 12 ADHD children and 26 controls (ages 6-14 years) were tested using a time reproduction task in which subjects had to reproduce intervals of 12, 24, 36, 48, and 60 s. Four trials at each duration were presented with a distraction occurring on half of these trials. Control subjects were significantly more accurate than ADHD children at most durations and were unaffected by the distraction. ADHD children, in contrast, were significantly less accurate when distracted. Both groups became less accurate with increasing durations to be reproduced. Study II: Tested three doses of methylphenidate (MPH) and placebo on the time reproductions of the 12 ADHD children. ADHD children became less accurate with increasing durations and distraction was found to reduce accuracy at 36 s or less. No effects of MPH were evident. The results of these preliminary studies seem to support the prediction that sense of time is impaired in children with ADHD. The capacity to accurately reproduce time intervals in ADHD children does not seem to improve with administration of stimulant medication.

Molecular recognition in the HIV-1 capsid/cyclophilin A complex.

The HIV-1 capsid protein (CA) makes an essential interaction with the human peptidyl prolyl isomerase, cyclophilin A (CypA), that results in packaging of CypA into the virion at a CA to CypA stoichiometry of approximately 10:1. The 231 amino acid residue capsid protein is composed of an amino-terminal CypA binding domain (1 to approximately 151; CA151) and a carboxyl-terminal dimerization domain (approximately 151 to 231). We find that CypA binds dimeric CA and monomeric CA151 with identical intrinsic affinities (K[d] = 16(+/-4) microM). This result demonstrates that capsid dimerization and cyclophilin A binding are not thermodynamically coupled and suggests that the substoichiometric ratio of CypA in the HIV-1 virion results from the intrinsic stability of the CA/CypA complex. In the known co-crystal structure of the CA151/CypA complex, CypA binding is mediated exclusively by an exposed capsid loop that spans residues Pro85 to Pro93. The energetic contributions to CypA binding were quantified for each residue in this loop, and the results demonstrate that the Gly89-Pro90 dipeptide is the primary cyclophilin A recognition motif, with Pro85, Val86, His87, Ala88, and Pro93 also making energetically favorable contacts. These studies reveal that the active site of CypA, which can catalyze the isomerization of proline residues in vitro, also functions as a sequence-specific, protein-binding motif in HIV-1 replication.

Injuries among children in home and out-of-home care.

UNLABELLED: As the number of children receiving care in out-of-home settings increases in the United States, the risk of injury in such settings has become the subject of intense research. OBJECTIVES: This study examined the relative safety of out-of-home care compared with care in a child's own home. METHODS: This community based prospective cohort study of 656 families in three adjacent counties in the Piedmont region of North Carolina characterizes the patterns and rates of injuries among children less than 5 years of age in three child care settings, home care (HC), center based care (CBC), and other out-of-home care (OOHC). Information about minor and severe injuries was obtained from parents using monthly telephone interviews over a one year period. Statistical modeling designed to handle unbalanced data with correlated observations was used as the primary tool for analysis. RESULTS: Rate of minor injuries was highest in CBC, followed by HC, and then OOHC. However, these differences for OOHC may have been due to reporting biases and errors in rate estimates. There were no significant differences in severe injury rates among the three settings. CONCLUSIONS: The risk of serious injury among children under 5 in CBC is not different from that of children in HC or OOHC despite the fact that the risk of minor injury is higher.

Self-delivery of hemodialysis care: a therapy in itself.

Patient autonomy, sense of control, and well-being are thought to be enhanced by self-care hemodialysis as a therapy for end-stage renal disease. Dialysis in a satellite setting reduces travel time and can diminish therapy intrusiveness. Health-related quality of life (HRQOL), in terms of functional status and well-being, was measured in a group of patients trained for self-care, and then measured again after these patients were transferred to a satellite unit. Comparison was made with an age- and comorbidity-matched cohort of full-care patients. Patients trained for self-care tended to score higher than the full-care patients in the psychosocial domains of HRQOL, such as role function, social function, and emotional well-being, before and after transfer to the satellite unit. Physiological measurements did not differ significantly between groups at any time during the study, indicating that differences in HRQOL were not attributable to differences in metabolic stability. We conclude that patients trained for self-care hemodialysis experience better subjective quality of life than their full-care counterparts. This study highlights both the usefulness of measuring HRQOL as an outcome of hemodialysis therapy and the potential benefits of therapies such as self-care and satellite dialysis.