Olfactory Bulbectomy Impedes Social but Not Photic Reentrainment of Circadian Rhythms in Female Octodon degus

Recent studies demonstrated that nonphotic (social) cues markedly accelerate reentrainment to large phase shifts of the light-dark (LD) cycle in female Octodon degus and that such changes are likely effected by chemosensory stimuli. This experiment investigated the effects of olfactory bulbectomies on (1) socially facilitated reentrainment rates of circadian rhythms following a 6-h phase advance of the LD cycle, (2) photic reentrainment rates of circadian rhythms following a 6-h advance of the LD cycle, (3) photic entrainment, and (4) the circadian period (τ) of activity rhythms in constant darkness (DD). Olfactory bulbectomies (BX) blocked socially facilitated reentrainment rates but did not alter reentrainment rates of circadian rhythms to photic cues alone. In addition, BX lowered mean daily locomotor activity levels and decreased the amplitude of the activity rhythm in degus housed in entrained (LD 12:12) conditions but did not alter the phase of activity onset or offset, duration (α) of activity, or mean daily core body temperature. Bulbectomies also failed to modify τ of free-running activity rhythms. This experiment confirms that the olfactory bulbs and che mosensory cues are necessary for socially facilitated reentrainment. In contrast to their effects in nocturnal rodents, BX do not produce significant circadian photic changes in diurnal degus. This is the first experiment to determine that chemosensory stimuli modulate the circadian system in a diurnal rodent.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66499/2/10.1177_074873049701200408.pd

Octodon degus: A diurnal, social and long-lived rodent

Octodon degus is a moderate-sized, precocious, but slowly maturing, hystricomorph rodent from central Chile. We have used this species to study a variety of questions about circadian rhythms in a diurnal mammal that readily adapts to most laboratory settings. In collaboration with others, we have found that a number of fundamental features of circadian function differ in this diurnal rodent compared with nocturnal rodents, specifically rats or hamsters. We have also discovered that many aspects of the circadian system are sexually dimorphic in this species. However, the sexual dimorphisms develop in the presence of pubertal hormones, and the sex differences do not appear until after gonadal puberty is complete. The developmental timing of the sex differences is much later than in the previously studied altricial, rapidly developing rat, mouse, or hamster. This developmental timing of circadian function is reminiscent of that reported for adolescent humans. In addition, we have developed a model that demonstrates how nonphotic stimuli, specifically conspecific odors, can interact with the circadian system to hasten recovery from a phase-shift of the light:dark cycle (jet lag). Interestingly, the production of the odor-based social signal and sensitivity to it are modulated by adult gonadal hormones. Data from degu circadian studies have led us to conclude that treatment of some circadian disorders in humans will likely need to be both age and gender specific. Degus will continue to be valuable research animals for resolving other questions regarding reproduction, diabetes, and cataract development.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/60643/1/octodon_degus.pd

Sex differences and effects of social cues on daily rhythms following phase advances in Octodon degus

Two experiments were designed to determine whether social cues could enhance the rate of resynchronization in body temperature and general activity rhythms in male or female Octodon degus following a 6 h phase advance. The first experiment examined average resynchronization rates for animals in each condition. The second experiment examined resynchronization rates for a smaller group of animals, each treated as its own control. Female phase-shifters resynchronized temperature and activity rhythms significantly faster when housed with an entrained (donor) female than those females housed with another phase-shifting female or housed alone. Females housed with entrained males resynchronized their temperature rhythms significantly slower than females housed with entrained females. No differences in resynchronization rate for phase-shifting males existed between test conditions. However, activity rhythms of male controls (housed alone) reentrained significantly faster than those of female controls. These experiments demonstrate a sex difference in (i) reentrainment rate by photic cues alone; (ii) donors' effect on female phase-shifters' resynchronization; and (iii) phase-shifters' resynchronization response to donor cues. In these studies, resynchronization in the presence of another animal could either have been achieved by entrainment of the pacemaker or by masking of the circadian rhythms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/60641/1/sex_differences.pd

Female meadow voles have a preferred mating pattern predicted by photoperiod, which influences fertility

In a previous study, Meek and Lee (26) found that female meadow voles mated within three distinct time periods after pairing with a male, and fertility was influenced by the time of mating and photoperiod. In the present studies, we tested the hypothesis that different patterns of mating would correlate with high and low fertility. We found two very different patterns of mating were correlated with high fertility. Females housed in long daylengths (long day; 14 h light/day) and mating within 48 h of pairing with a male, received few mounts, intromissions, and intromissions per ejaculatory series, with very short interintromission intervals. All long-day females utilizing this mating pattern ovulated, and 86-100% produced litters. We suggest this pattern of mating is associated with spontaneous estrus. In contrast to long-day females mating within 48 h, females housed in short daylengths (short day; 10 h light/day) and mating between 14-48 h after pairing with a male, received significantly more short mounts and intromissions, with longer interintromission intervals. These short day females all ovulated and 86% produced litters. We suggest that this pattern of mating is associated with an induced estrus. Short-day females that did not exhibit this pattern of mating (66%) produced far fewer litters. We discuss two mechanisms by which fertility may be inhibited in most short-day females.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30434/1/0000055.pd

Sex differences and effects of prenatal exposure to excess testosterone on ventral tegmental area dopamine neurons in adult sheep

Prenatal testosterone (T) excess in sheep results in a wide array of reproductive neuroendocrine deficits and alterations in motivated behavior. The ventral tegmental area (VTA) plays a critical role in reward and motivated behaviors and is hypothesised to be targeted by prenatal T. Here we report a sex difference in the number VTA dopamine cells in the adult sheep, with higher numbers of tyrosine hydroxylase (TH)‐immunoreactive (‐ir) cells in males than females. Moreover, prenatal exposure to excess T during either gestational days 30–90 or 60–90 resulted in increased numbers of VTA TH‐ir cells in adult ewes compared to control females. Stereological analysis confirmed significantly greater numbers of neurons in the VTA of males and prenatal T‐treated ewes, which was primarily accounted for by greater numbers of TH‐ir cells. In addition, immunoreactivity for TH in the cells was denser in males and prenatal T‐treated females, suggesting that sex differences and prenatal exposure to excess T affects both numbers of cells expressing TH and the protein levels within dopamine cells. Sex differences were also noted in numbers of TH‐ir cells in the substantia nigra, with more cells in males than females. However, prenatal exposure to excess T did not affect numbers of TH‐ir cells in the substantia nigra, suggesting that this sex difference is organised independently of prenatal actions of T. Together, these results demonstrate sex differences in the sheep VTA dopamine system which are mimicked by prenatal treatment with excess T.We report a sex difference in ventral tegmental area (VTA) dopamine cells in the adult sheep with higher numbers of tyrosine hydroxylase (TH)‐immunoreactive cells in males than females. Moreover, prenatal exposure to excess T during gestational days 30–90 or 60–90 caused increased numbers of VTA TH‐immunoreactive cells in adult ewes compared to control females. Sex differences were also demonstrated in the substantia nigra, but prenatal T had no effect on TH in this area. Results indicate that sex differences and prenatal exposure to excess T affects both numbers of cells expressing TH and the protein levels in the VTA.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111123/1/ejn12871.pd

Size matters but when, why and for whom?

Pack size of tobacco products, including factory-made cigarettes and loose tobacco, is an important but neglected aspect of tobacco control policy. Understanding the nature of the relationship between pack size and consumption, as well as the underlying mechanisms, is key for informing effective policy and reducing smoking prevalenc

What hispanic parents do to encourage and discourage 3-5 year old children to be active : a qualitative study using nominal group technique

Purpose : Hispanic preschoolers are less active than their non-Hispanic peers. As part of a feasibility study to assess environmental and parenting influences on preschooler physical activity (PA) (Niños Activos), the aim of this study was to identify what parents do to encourage or discourage PA among Hispanic 3-5 year old children to inform the development of a new PA parenting practice instrument and future interventions to increase PA among Hispanic youth. Methods : Nominal Group Technique (NGT), a structured multi-step group procedure, was used to elicit and prioritize responses from 10 groups of Hispanic parents regarding what parents do to encourage (5 groups) or discourage (5 groups) preschool aged children to be active. Five groups consisted of parents with low education (less than high school) and 5 with high education (high school or greater) distributed between the two NGT questions. Results : Ten NGT groups (n = 74, range 4-11/group) generated 20-46 and 42-69 responses/group for practices that encourage or discourage PA respectively. Eight to 18 responses/group were elected as the most likely to encourage or discourage PA. Parental engagement in child activities, modeling PA, and feeding the child well were identified as parenting practices that encourage child PA. Allowing TV and videogame use, psychological control, physical or emotional abuse, and lack of parental engagement emerged as parenting practices that discourage children from being active. There were few differences in the pattern of responses by education level. Conclusions : Parents identified ways they encourage and discourage 3-5 year-olds from PA, suggesting both are important targets for interventions. These will inform the development of a new PA parenting practice scale to be further evaluated. Further research should explore the role parents play in discouraging child PA, especially in using psychological control or submitting children to abuse, which were new findings in this study

Pharmacists’ use of guidelines for the supply of non-prescription medicines: a cross-sectional survey

Objectives: Guidelines support best practice for healthcare practice. In Australia, some non-prescription medicines are only accessible after consultation with a pharmacist and are known as Pharmacist Only medicines. Guidelines for providing some Pharmacist Only medicines are available, however, it is currently unknown if and how these guidelines are used in practice.// The objective was to characterise pharmacists’, intern pharmacists and pharmacy students’ use of guidelines for Pharmacist Only medicines.// Methods: A cross-sectional electronic survey of Australian registered pharmacists, intern pharmacists and pharmacy students was administered in July 2020. Questions explored the participants’ use of Pharmacist Only medicine guidelines (available both in print and online; available online only) in the preceding 12 months. Data were analysed descriptively (i.e. frequencies, percentages).// Key findings: In total, 574 eligible respondents completed the survey. Overall, 396 (69%) reported accessing the online and in-print guidelines in the previous 12 months with 185 (33%) accessing online-only guidelines. The guideline on emergency contraception was used the most out of all guidelines in the past 12 months (278, 48%). Overall, respondents reported accessing guidelines to update knowledge, check their practice reflected best practice and content familiarisation. Respondents’ reasons for not accessing guidelines were due to respondents stating they did not need the information or that they had previously accessed the guidelines more than 12 months ago. These reasons varied between respondent groups.// Conclusions: Access and use of the Pharmacist Only medicines guidelines varied between pharmacists, interns and students. Further understanding of the influences of the use of these guidelines will help inform professional bodies on how best to develop guidelines to increase consistent use in practice and implement interventions to increase use./

Use of a reference text by pharmacists, intern pharmacists and pharmacy students: a national cross-sectional survey

Background: Reference texts assist pharmacists by addressing knowledge gaps and enabling evidence-based decisions when providing patient care. It is unknown whether reference text utilisation patterns differ between pharmacists, intern pharmacists and pharmacy students. To describe and compare the self-reported use and perceptions of a reference text, namely the national formulary, by pharmacists, intern pharmacists and pharmacy students. // Methods: Registered pharmacists, intern pharmacists and pharmacy students living in Australia were surveyed in July 2020. The survey was electronic and self-administered. Questions considered self-reported use of a specific reference text in the preceding 12 months. // Key findings: There were 554 eligible responses out of 774 who commenced the survey: 430 (78%) pharmacists, 45 (8%) intern pharmacists and 79 (14%) pharmacy students. Most participants (529/554, 96%) reported historical use of the text, though pharmacists were significantly less likely than intern pharmacists and students to use it frequently (52/422, 12% versus 16/43, 37% versus 23/76, 30%, P < 0.001). Pharmacists (44%, 177/404) reported using the text as a tool to resolve a situation when providing a service or patient care (177/404, 44%) or as a teaching resource (150/404, 38%). In contrast, intern pharmacists and students most commonly use these to familiarise themselves with the contents (30/43, 70%; 46/76, 61%) or update their knowledge (34/43, 79%; 53/76, 70%). // Conclusions: Access and use patterns varied significantly across career stages. A broader understanding of the use of reference texts may help develop interventions to optimise the content and usability. Varying usage patterns across the groups may inform the tailoring of texts for future use