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Abstract: An initial administration of 60% nitrous oxide (N2O) evokes hypothermia in rats and if the administration continues for more than 1–2h, acute tolerance typically develops such that the initial reduction in core temperature (Tc) reverses and Tc recovers toward control values. Calorimeter studies at normal ambient temperature indicate that hypothermia results from a transient reduction in heat production (HP) combined with an elevation in heat loss. Acute tolerance develops primarily due to progressive increases in HP. Our aim was to determine whether rats provided a choice of ambient temperatures would behaviorally facilitate or oppose N2O-induced hypothermia. A gas-tight thermally-graded alleyway (range, 6.7–37.0°C) enabled male Long–Evans rats (n=12) to select a preferred ambient temperature during a 5-hour steady-state administration of 60% N2O and a separate paired control gas exposure (order counterbalanced). Tc was measured telemetrically from a sensor surgically implanted into the peritoneal cavity >7days before testing. Internal LED lighting maintained the accustomed day:night cycle (light cycle 0700–1900h) during sessions lasting 45.5h. Rats entered the temperature gradient at 1100h, and the 5-h N2O or control gas period did not start until 23h later to provide a long habituation/training period. Food and water were provided ad libitum at the center of the alleyway. The maximum decrease of mean Tc during N2O administration occurred at 0.9h and was −2.05±0.25°C; this differed significantly (p<0.0001) from the corresponding Tc change at 0.9h during control gas administration (0.01±0.14°C). The maximum decrease of the mean selected ambient temperature during N2O administration occurred at 0.7h and was −13.58±1.61°C; this differed significantly (p<0.0001) from the corresponding mean change in the selected ambient temperature at 0.7h during control gas administration (0.30±1.49°C). N2O appears to induce a regulated hypothermia because the selection of a cool ambient temperature facilitates the reduction in Tc. The recovery of Tc during N2O administration (i.e., acute tolerance development) could have been facilitated by selection of ambient temperatures that were warmer than those chosen during control administrations, but interestingly, this did not occur. [Copyright &y& Elsevier]

Studies using core temperature (Tc) have contributed greatly to theoretical explanations of drug tolerance and its relation- ship to key features of addiction, including dependence, withdrawal, and relapse. Many theoretical accounts of tolerance propose that a given drug-induced psychobiological disturbance elicits opponent responses that contribute to tolerance development. This proposal and its theoretical extensions (e.g., conditioning as a mechanism of chronic tolerance) have been inferred from dependent variables, such as Tc, which represent the summation of multiple underlying determinants. Direct measurements of determinants could increase the understanding of opponent processes in tolerance, dependence, and withdrawal. The proximal determinants of Tc are metabolic heat production (HP) and heat loss (HL). We developed a novel system for simultaneously quantifying HP (indirect calorimetry), HL (direct gradient layer calorimetry), and Tc (telemetry) during steady-state administrations of nitrous oxide (N2O), an inhalant with abuse potential that has been previously used to study acute and chronic tolerance development to its hypothermia-inducing property. Rats were administered 60% N2O (n = 18) or placebo gas (n = 16) for 5 h after a 2-h placebo baseline exposure. On average, N2O rapidly but transiently lowered HP and increased HL, each by ∼16% (P < 0,001). On average, rats reestablished and maintained thermal equilibrium (HP = HL) at a hypothermic Tc (-1.6°C). However, some rats entered positive heat balance (HP > HL) after becoming hypothermic such that acute tolerance developed, i.e., Tc rose despite continued drug administration. This work is the first to directly quantify the thermal determinants of Tc during administration of a drug of abuse and establishes a new paradigm for studying opponent processes involved in acute and chronic hypothermic tolerance development. [ABSTRACT FROM AUTHOR]

This study examined the relation of infant emotional responses of anger and sadness to cortisol response in 2 goal blockage situations. One goal blockage with 4-month-old infants (N = 56) involved a contingency learning procedure where infants' learned response was no longer effective in reinstating an event. The other goal blockage with 6-month-old infants (N = 84) involved the still face procedure where infants' reactions to their mothers' lack of responsivity were not effective in reestablishing interaction. For both blockages, sadness was related to cortisol response, though anger was not--the greater the sadness, the higher the cortisol response. This differential relation is consistent with other evidence indicating the more positive role of anger as opposed to sadness in overcoming an obstacle. [ABSTRACT FROM AUTHOR]

This study examined the relation of visual self-recognition to personal pronoun use and pretend play. For a longitudinal sample (N=66) at the ages when self-recognition was emerging (15, 18, and 21 months), self-recognition was related to personal pronoun use and pretend play such that children showing self-recognition used more personal pronouns and demonstrated more advanced pretend play than did children not showing self-recognition. The finding of a relation among these measures provides additional evidence that in the middle of the 2nd year of life a metarepresentation of self emerges in the human child. [ABSTRACT FROM AUTHOR]

This study examined relations between reactivity (i.e., peak response) and regulation (i.e., response dampening) in 6-month-old infants' cortisol and behavioral responses to inoculation (N = 62). Data showed that reactivity and regulation were unrelated for both cortisol and behavior. The independence of reactivity and regulation suggests that measures of both are needed to characterize infant cortisol or behavioral response to stress more completely. For both reactivity and regulation, cortisol and behavior were unrelated, suggesting that measures of both are needed to assess infant stress more adequately. There was considerable variation in the timing of the peak cortisol response, suggesting that obtaining only a single poststressor cortisol sample does not provide a sensitive measure of cortisol reactivity. [ABSTRACT FROM AUTHOR]

This study examined individual differences in 4-year-old children's (N = 60) expression of the self-conscious emotions of embarrassment and shame and their relation to differences in cortisol response to stress. Results indicated the presence of two different types of embarrassment--one that reflected negative evaluation of the self, and the other a nonevaluative type that reflected simply exposure of the self when the individual was the object of attention of others. Results also indicated a relation between a higher cortisol response to stress and the greater expression of the self-conscious emotions of evaluative embarrassment and shame that reflected negative self-evaluation. [ABSTRACT FROM AUTHOR]

Previous research has suggested that a relationship exists between craniofacial morphology and tooth wear. Theprimary objective of this study was to determine whether an individual's craniofacial morphology during childhood is relatedto the degree of tooth wear that occurs in that same individual's adult dentition. Pretreatment orthodontic records taken duringthe mixed dentition (T1) and follow-up records takenan average of 20years later (T2) were available for 165 orthodontic patients.Incisal/occlusal tooth wear was measured on a tooth-by-tooth basis from T1 and T2 casts using a four-category scoring system.Measures of craniofacial morphology were made from the T1 lateral cephalometric radiograph. Multiple regression analysisindicated that adult wear was associated with the T1 cephalometric measures of ANB (p = 0.017) and the interaction betweenramal height and sex (p = 0.039). These results suggest that the craniofacial morphology observed during childhood has a smallbut significant relationship to adult tooth wear. [ABSTRACT FROM AUTHOR]

SUMMARY After cockroaches were trained to traverse an illuminated runway with darkness as the rewarding event, they were given brief "primes" of darkness in the startbox. Runway performance was enhanced, but these priming effects declined as postprime delay (i.e., the delay before a roach was permitted to leave the startbox) was increased. A second experiment found that the response enhancement was greater after primes of long duration than after primes of short duration. The present work suggests a possible distinction between the priming properties of food and water on the other hand, and darkness, brain stimulation, and an imprinting object on the other. [ABSTRACT FROM AUTHOR]

The effect of maternal soothing to infant inoculation as well as everyday distress on infant cortisol and behavioral responses to stress was examined in two longitudinal samples of 55 and 74 infants, respectively, between 2 and 6 months of age. There was no evidence that maternal soothing was effective in reducing infants' cortisol or behavioral responses to stress. The absence of this relation occurred despite evidence for cross-time stability and cross-situation consistency in maternal soothing. That maternal soothing plays little role in lowering infant responses to stress leaves open the possibilities that other maternal behaviors may mediate children's distress or that infant temperament may be related to infant stress. [ABSTRACT FROM AUTHOR]

Investigates whether early differences in reactivity to stress are related to self-recognition at 18 months of age. Information on adrenocortical and behavioral stress; What objective self-awareness involves; Role of maturational factors in the variation in the timing of self-recognition; Details on the relation between brain function and development.

Introduction: Patients may express views about their orthodontic care by posting publicly available reviews on the Internet. This study analyzed online reviews of orthodontists with an emphasis on the types and frequency of complaints expressed in negative reviews.Methods: A random sample of 10.6% of the American Association of Orthodontists membership was evaluated to identify members practicing in a North American office that is limited to orthodontics and has an online presence. Information regarding those orthodontists and their offices was collected. For offices with Google and/or Yelp reviews, all negative (1- or 2-star) reviews were saved for content analysis. If an office posted a response to a negative review, those responses were also collected for analysis.Results: Of the 807 eligible orthodontists, 92.4% had reviews on Google and/or Yelp. Average ratings of orthodontists were very positive (ie, 4- and 5-star reviews constituted >97% of Google reviews and >88% of Yelp reviews), yielding an average orthodontist rating of 4.72 on Google and 4.42 on Yelp. However, approximately half of those orthodontists (50.9%) also had at least 1 negative review. The 3 most frequently mentioned categories of complaints were regarding quality of care and/or service, interpersonal interactions, and money and/or financial issues. An analysis of the specific kinds of complaints is described. Orthodontists posting responses to negative reviews had significantly better average ratings than those who did not, but this association does not demonstrate a causal relationship.Conclusions: Understanding the complaints orthodontic patients express in online reviews may suggest strategies to improve patient satisfaction and an orthodontist's online reputation. [ABSTRACT FROM AUTHOR]

Introduction: The objectives of this research were to identify the beliefs and practices of orthodontists about mouthguard use in orthodontic patients and to survey orthodontic patients currently playing school-sponsored basketball and/or football about mouthguards.Methods: Fifteen orthodontists were interviewed about mouthguard use in their patients. Patients (aged 11-18 years) playing organized school basketball (n = 53) or football (n = 22) from 13 of those 15 orthodontic practices participated in an online survey about mouthguards.Results: Approximately half of the orthodontists interviewed had initiated discussions about mouthguards with their patients. Although boil-and-bite mouthguards were recommended most often by orthodontists with only a single orthodontist recommending a stock type, stock was the most commonly used type (football [59%], basketball [50%]) followed by boil-and-bite (football [27%], basketball [35%]). Only 2 of the 75 patients surveyed (<3%) reported using a custom mouthguard. All football players reported using a mouthguard, as mandated by this sport. Basketball does not mandate mouthguard use, and only 38% of basketball players reported wearing one. Players who used mouthguards cited forgetting as the most frequent reason for not always using one. A greater percentage of football (91%) than basketball (32%) players reported that their coach recommended a mouthguard (P <0.001).Conclusions: Orthodontists differ in how they approach mouthguard use by their patients, which likely reflects a lack of evidence-based guidelines. The beliefs, recommendations, and practices of orthodontists concerning mouthguard use and the use of mouthguards by orthodontic patients are discussed. Research directions to improve mouthguard use are suggested. [ABSTRACT FROM AUTHOR]