Latent inhibition of a conditioned taste aversion in fetal rats.

The etiology of schizophrenia's cognitive symptoms may have its basis in prenatal alterations of glutamate N-methyl-D-aspartate (NMDA) receptor functioning. Therefore, the current study investigated the effects of ketamine (an NMDA receptor blocking drug) on both a conditioned taste aversion (CTA) and latent inhibition (LI; a model of attentional capacity) in rat fetuses. We first sought to determine if a CTA could be diminished by nonreinforced preexposure to a CS in fetal rats (i.e., LI). We injected E18 pregnant Sprague-Dawley rats with 100% allicin (garlic taste) or an equal volume of saline. Some of the pregnant dams also received ketamine (100 mg/kg, i.p.). One day later (E19), the dams received a second injection of the CS, followed by either lithium chloride (the US) or saline. Finally, on E21 pups received oral lavage with allicin and observations of ingestive orofacial motor responses were recorded. When allicin had been paired with LiCl in utero, E21 fetuses exhibited a conditioned suppression of orofacial movements, indicative of an aversion to this taste. Preexposure to the garlic taste on E18 produced a LI of this CTA. Ketamine significantly disrupted the formation of the CTA and had some impact on LI. However, the direct effect of ketamine on LI is less certain since the drug also blocked the original CTA.

Exploring a practitioner-athlete relationship and facilitated learning throughout a psychological skills training program.

Psychological skills training (PST) programs have been consistently reported as an important part of preparation for optimal performance in high performance sport. However, there is much less research about the quality and characteristics of the working relationship between a sport psychology practitioner (SPP) and an athlete and, importantly, how that relationship facilitates learning. Therefore, the purpose of the present paper was to explore the working relationship between a SPP and a volleyball player and how that working relationship facilitated the learning processes utilized by this player, as she prepared for the demands of her sport and life. An instrumental case study methodology with a qualitative description approach was employed to illustrate different aspects of the evolving relationship and the athlete's experiences. The results of this case reflect an approach that combined features of both a directive approach in teaching specific psychological skills and a less directive and more collaborative approach, which, in turn, allowed an athlete to begin to learn how to guide their own learning.

Experience and Management of Fear in Men's World Cup Alpine Ski Racing.

Alpine ski racers, specifically in the discipline of downhill, may experience fear competing in such a high-risk environment. The purpose of this study was to explore Canadian national team men's experience and management of fear in World Cup alpine ski racing. This study uses an interpretive phenomenological analysis, conducted with five male members of the Canadian national ski team. Three themes emerged: contextual influences, preparation and process, and risk vs. reward. The findings indicate one's experience and management of fear may be influenced by contextual factors (e.g., weather, course profile) and confidence, and that confidence is influenced by the same situational factors that influence fear as well as athlete preparation. There currently exists a discrepancy between the athletes' approaches to training and racing, making it difficult to master fear management strategies. As a result of the discrepancy created between training and racing, there are several implications for how the national team environment and training is structured, and we present recommendations for how these findings can be applied to training.

Chronic dietary magnesium-L-threonate speeds extinction and reduces spontaneous recovery of a conditioned taste aversion.

Elevation of brain magnesium enhances synaptic plasticity and extinction of conditioned fear memories. This experiment examined the generalizability of this phenomenon by studying the effects of a novel magnesium compound, magnesium-L-threonate (MgT), on conditioned taste aversion (CTA) extinction and spontaneous recovery (SR). Adult male Sprague-Dawley rats were maintained on a 23-hour water deprivation cycle and acquired a CTA following the taste of a CS [0.3% saccharin+16 mg/ml MgT (SAC+MgT)] paired with a US [81 mg/kg (i.p.) lithium chloride (LiCl)]. Following CTA acquisition, rats drank a water+MgT solution for up to 1 hour/day over the next 31 days. For 14 additional days, some animals continued water+MgT treatment, but others drank water only to allow MgT to be eliminated from the body. We then employed 2 different extinction paradigms: (1) CS-Only (CSO), in which SAC was presented, every-other day, or (2) Explicitly Unpaired (EU), in which both SAC and LiCl were presented, but on alternate days. EU extinction procedures have been shown to speed CTA extinction and reduce spontaneous recovery of the aversion. Throughout extinction, half of the rats in each group continued to drink MgT (now in SAC or supplemental water+MgT solution), whereas the other half drank SAC only/water only until SAC drinking reached ≥90% of baseline (asymptotic extinction). Rats receiving MgT just before/during extinction drank less SAC on the first day of extinction suggesting that they had retained a stronger CTA. MgT enhanced the rate of extinction. Furthermore, the MgT-treated rats showed a relatively modest SR of the CTA 30 days later - indicating that the extinction procedure was more effective for these animals. Our data suggest that long-term dietary MgT may enhance the consolidation/retention of a CTA, speed extinction, and inhibit SR of this learned aversion.

Stimulation of the dorsal periaqueductal gray enhances spontaneous recovery of a conditioned taste aversion.

Due to its relevance to clinical practice, extinction of learned fears has been a major focus of recent research. However, less is known about the means by which conditioned fears re-emerge (i.e., spontaneously recover) as time passes or contexts change following extinction. The periaqueductal gray represents the final common pathway mediating defensive reactions to fear and we have reported previously that the dorsolateral PAG (dlPAG) exhibits a small but reliable increase in neural activity (as measured by c-fos protein immunoreactivity) when spontaneous recovery (SR) of a conditioned taste aversion (CTA) is reduced. Here we extend these correlational studies to determine if inducing dlPAG c-fos expression through electrical brain stimulation could cause a reduction in SR of a CTA. Male Sprague-Dawley rats acquired a strong aversion to saccharin (conditioned stimulus; CS) and then underwent CTA extinction through multiple non-reinforced exposures to the CS. Following a 30-day latency period after asymptotic extinction was achieved; rats either received stimulation of the dorsal PAG (dPAG) or stimulation of closely adjacent structures. Sixty minutes following the stimulation, rats were again presented with the saccharin solution as we tested for SR of the CTA. The brain stimulation evoked c-fos expression around the tip of the electrodes. However, stimulation of the dPAG failed to reduce SR of the previously extinguished CTA. In fact, dPAG stimulation caused rats to significantly suppress their saccharin drinking (relative to controls) - indicating an enhanced SR. These data refute a cause-and-effect relationship between enhanced dPAG c-fos expression and a reduction in SR. However, they highlight a role for the dPAG in modulating SR of extinguished CTAs.

Pigment epithelium-derived factor decreases outflow facility.

PURPOSE: Pigment epithelium-derived factor (PEDF) regulates blood-retinal barrier function. As a constituent of aqueous humor, the role of PEDF in conventional outflow function is unknown. The goals of the study were to examine the effects of PEDF on barrier function of cultured Schlemm's canal (SC) endothelia and outflow facility in mouse eyes in situ. METHODS: To model the inner wall of SC, transendothelial electrical resistance (TEER) of human SC and porcine angular aqueous plexus (AAP) cells was monitored. To examine an intact conventional outflow pathway, enucleated eyes from culled C57BL/6 mice were perfused with PEDF using a computer-controlled system. Purified PEDF (0.1 and 1 µg/mL) was perfused at four different pressure steps (4, 8, 15, 20 mm Hg), measuring flow to determine outflow facility (slope of flow/pressure relationship). RESULTS: Pigment epithelium-derived factor increased TEER of porcine AAP cells in a dose-dependent fashion (0.3-3 µg/mL), and 1 µg/mL recombinant PEDF or conditioned media from pigmented retinal pigment epithelial monolayers stabilized TEER of human SC monolayers over time (0-48 hours). In perfusion experiments, we observed a 43.7% decrease in outflow facility (0.016 vs. 0.029 µL/min/mm Hg, P = 4.5 × 10⁻5) in eyes treated with 1 µg/mL PEDF compared to vehicle-perfused controls, and a 19.9% decrease (0.021 vs. 0.027 µL/min/mm Hg, P = 0.003) at 100 ng/mL PEDF. CONCLUSIONS: Pigment epithelium-derived factor increased barrier function in both the in vitro and in situ models of the inner wall of SC. Modification of PEDF signaling in SC cells may be therapeutically exploited to increase outflow facility in people with ocular hypertension or decrease outflow facility in those with hypotony.

Long-term outcomes after percutaneous radiofrequency ablation for renal cell carcinoma.

OBJECTIVES: To assess the long-term oncological efficacy of radiofrequency ablation (RFA) for treatment of renal cell carcinoma (RCC). METHODS: In this institutional review board-approved, retrospective study, the records and imaging studies for all RCC patients treated with percutaneous RFA before 2005 were reviewed and analyzed. RESULTS: A total of 48 RCCs in 41 patients were treated with RFA. Median size of RCC treated was 2.6 cm (range: 0.7-8.2 cm). Of the 48 treated RCCs, 5 (12%) had recurrent tumor after a single ablation session. The median size of the index lesion in the cases with recurrence was 5.2 cm (interquartile range [IQR]: 4-5.3) compared with 2.2 cm (IQR: 1.7-3.1, P = .0014) without local recurrence. There were no recurrences when RCCs less than 4 cm were treated. Seventeen (41%) patients with 18 treated RCCs died during the follow-up period at a median time of 34 (IQR: 10-47) months. One patient (2%) died of metastatic RCC, whereas 16 died of unrelated causes. Twenty-four patients with 30 RCCs treated with RFA survived. For the remaining 30 RCCs, median follow up was 61 months (IQR: 54-68). No patients in this group of survivors had metastatic RCC, 1 had recurrence diagnosed at 68 months. The long-term recurrence-free survival rate was 88% after RFA. CONCLUSIONS: RFA can result in durable oncological control for RCCs less than 4 cm. RFA is an effective treatment option for patients with RCCs less than 4 cm who are poor surgical candidates. For patients with larger RCCs alternative treatments should be considered.

Away-from-home food intake and risk for obesity: examining the influence of context.

OBJECTIVE: This study examined sociodemographic and cultural determinants of away-from-home food consumption in two contexts and the influence of frequency of away-from-home food consumption on children's dietary intake and parent and child weight status. METHODS AND PROCEDURES: Parents of children (N=708) in grades K-2 were recruited from 13 elementary schools in Southern California. Parents were asked through a questionnaire the frequency with which they eat meals away from home and the restaurant they frequented most often. The height and weight of the parents and their children were measured to calculate BMI. RESULTS: Consuming foods at least once a week from relatives/neighbors/friends (RNF) homes was associated with children's dietary intake and children's risk for obesity. For example, children of parents with weekly or greater RNF food consumption drank more sugar-sweetened beverages. Parents of families who ate at restaurants at least weekly reported that their children consumed more sugar-sweetened beverages, more sweet/savory snacks, and less water compared with families who did not frequent restaurants this often. The type of restaurant visited did not affect diet intake or obesity. More acculturated families exhibited less healthy dietary behaviors than less acculturated families. DISCUSSION: Restaurants remain an important setting for preventing child and adult obesity, but other settings outside the home need to be considered in future intervention research. This may especially involve eating in the homes of RNF.