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Hormone signalling during critical periods organises the adult circadian timekeeping system by altering adult hormone sensitivity and shaping fundamental properties of circadian rhythmicity. However, the timing of when developmental oestrogens modify the timekeeping system is poorly understood. To test the hypothesis that alterations in postnatal oestrogenic signalling organise adult daily activity rhythms, we utilised aromatase knockout mice (Ar KO), which lack the enzyme required for oestradiol synthesis. Ar KO and wild-type ( WT) males and females were administered either oestradiol (E) or oil (OIL) daily for the first 5 postnatal days (p1-5E and p1-5 OIL, respectively) because this time encompasses the emergence of clock gene rhythmicity and light responsiveness in the suprachiasmatic nucleus, a bilateral hypothalamic structure regarded as the 'master oscillator'. After sexual maturation, gonadectomy and exogenous oestradiol supplementation, locomotor parameters were assessed. We determined that altered oestrogenic signalling in early life exerts organisational control over the expression of daily and circadian activity rhythms in adult mice. Specifically, p1-5E reduced total wheel running activity in male and female Ar KO and female WT mice but had no effect on WT male activity levels. In females, wheel running was consolidated by p1-5E to the early versus late evening, a phenomenon characteristic of male mice. The time of peak activity was advanced by p1-5E in WT and Ar KO females but not males. P1-5E shortened the length of the active phase (alpha) in WT males but had no effect on Ar KO males or females of either genotypes. Finally, p1-5E altered the magnitude of photic-induced shifts, suggesting that developmental oestrogenic signalling impacts adult circadian functions. In the present study, we further define both a critical period of development of the adult timekeeping system and the role that oestrogenic signalling plays in the expression of daily and circadian activity rhythms throughout life. [ABSTRACT FROM AUTHOR]

There are sex differences in free-running rhythms, activity level and activity distribution that are attributed, in part, to the action of gonadal hormones. We tested the hypothesis that non-classical estrogenic signaling pathways at estrogen receptor subtype 1 ( ESR1) modify the amplitude and phase of activity. We used ESR1 knock-out mice ( ERKO) and non-classical estrogen receptor knock-in mice ( NERKI). ERKO animals are unable to respond to estrogen at the ESR1 and NERKI animals lack the ability to respond to estrogens via the estrogen response element-mediated pathway, but can still respond via non-classical mechanisms. We compared intact male and female ERKO, NERKI and wildtype ( WT) mice with respect to total wheel-running activity, activity distribution across the 24-h day, phase angle of activity onset and free-running period ( τ) and the duration of activity in constant conditions. WT females had significantly greater activity than WT males, and this activity was more consolidated to the dark phase of the light:dark cycle. These sex differences were absent in the NERKI and ERKO animals. Among females, NERKI and ERKO animals had greater activity during the light phase than WT counterparts. Additionally, we have identified a novel contribution of non-classical estrogen signaling pathways on the distribution of activity. Our data suggest that total activity is ESR1-dependent and daily activity patterns depend on both classical and non-classical actions of estrogens. These data will aid in identifying the mechanisms underlying sex differences in sleep-wake cycles and the influence of steroid hormones on circadian patterns. [ABSTRACT FROM AUTHOR]

Radiography makes an essential contribution to the processes of examination, diagnosis and treatment planning in dentistry. While the use of film-based imaging still predominates in dentistry, digital imaging is gaining wider acceptance and the use of this modality is anticipated to expand in the future. Two concerns associated with this transition have been raised in the literature. The first of these is the dissatisfaction experienced by many dental professionals with quality of digital radiographs when compared to plain film. In addition, there are indications that practitioners feel limited in their understanding of those factors impacting on digital image quality. One key area highlighted in the literature as having a significant influence on digital radiographic quality and interpretation concerns the performance of the display device. Within the last decade, research derived from the fields of medical radiology and physics have demonstrated that suboptimally performing displays degrade image quality, thereby increasing the potential for compromised diagnostic outcomes. In the field of medicine, this has resulted in the establishment of standards applicable to computer displays used in diagnostic radiology. Conversely, limited guidelines exist in the field of dentistry. The aim of this review is to provide an outline of these standards and highlight the important relationship between computer display performance and digital image quality. [ABSTRACT FROM AUTHOR]

Preclinical research and learning theory suggest that a longer duration of varenicline treatment prior to the target quit date (TQD) would reduce smoking rates before cessation and improve abstinence outcomes. A double-blind randomized controlled trial tested this hypothesis in 60 smokers randomized to either an Extended run-in group (4 weeks of pre-TQD varenicline) or a Standard run-in group (3 weeks of placebo, 1 week of pre-TQD varenicline); all the participants received 11 weeks of post-TQD varenicline and brief counseling. During the pre-quit run-in, the reduction in smoking rates was greater in the Extended run-in group than in the Standard run-in group (42% vs. 24%, P < 0.01), and this effect was greater in women than in men (57% vs. 26%, P = 0.001). The rate of continuous abstinence during the final 4 weeks of treatment was higher among women in the Extended group compared to women in the Standard run-in group (67% vs. 35%). Although these data suggest that extension of varenicline treatment reduces smoking during the pre-quit period and may further enhance cessation rates, confirmatory evidence is needed from phase III clinical trials. [ABSTRACT FROM AUTHOR]

Diurnal and nocturnal animals differ with respect to the time of day at which the ovulatory surge in luteinizing hormone occurs. In some species this is regulated by the suprachiasmatic nucleus (SCN), the primary circadian clock, via cells that contain vasoactive intestinal polypeptide (VIP) and vasopressin (AVP). Here, we evaluated the hypothesis that chronotype differences in the timing of the luteinizing hormone surge are associated with rhythms in expression of the genes that encode these neuropeptides. Diurnal grass rats ( Arvicanthis niloticus) were housed in a 12/12-h light–dark cycle and killed at one of six times of day (Zeitgeber time 1, 5, 9, 13, 17, 21; ZT 0 = lights-on). In-situ hybridization was used to compare levels of vip, avp and VIP receptor mRNA ( vipr2) in the SCN of intact females, ovariectomized females, ovariectomized females given estradiol and intact males. We found a sex difference in vip rhythms with a peak occurring at ZT 13 in males and ZT 5 in intact females. In all groups avp mRNA rhythms peaked during the day, from ZT 5 to ZT 9, and had a trough in the dark at ZT 21. There was a modest rhythm and sex difference in the pattern of vipr2. Most importantly, the patterns of each of these SCN rhythms relative to the light–dark cycle resembled those seen in nocturnal rodents. Chronotype differences in timing of neuroendocrine events associated with ovulation are thus likely to be generated downstream of the SCN. [ABSTRACT FROM AUTHOR]

OBJECTIVE: It is widely recognised that individuals residing in regional or rural areas have poorer health outcomes than those from metropolitan areas. Factors associated with these poorer health outcomes include geographical isolation, population declines, limited health care provision and higher levels of inactivity compared to urban areas. The mental, social and physical health of individuals and communities in rural areas can be improved through active participation in sport and recreation activities. Unfortunately, participation in such activities can potentially lead to injury. There is a suggestion that there is an increased risk of sports injuries in rural areas due to the lack of health professionals and coaching personnel, fewer available volunteers to organise and deliver sport, and the general attitude towards injuries in rural settings. RESULTS: There is very limited information about the number and types of injuries sustained during participation in sports activities in rural and regional settings. This is largely related to a lack of formal sporting structures and support mechanisms including research funding and trained personnel. CONCLUSION: A range of factors need to be implemented to improve safety for sporting and recreational participants in these areas. These include improved monitoring of injury occurrence, stronger promotion of safety initiatives and wider implementation of education strategies. [ABSTRACT FROM AUTHOR]

Abstract: Desmosomes are major intercellular adhesion junctions that provide stable cell–cell contacts and mechanical strength to epithelial tissues by anchoring cytokeratin intermediate filaments of adjacent cells. Desmogleins (Dsg) are transmembrane core components of the desmosomes, and belong to the cadherin supergene family of calcium-dependent adhesion molecules. Currently, there are three known isoforms of Dsgs (Dsg1, Dsg2, and Dsg3), encoded by distinct genes that are differentially expressed to determine their tissue specificity and differentiation state of epithelial cells. In this study, we cloned a novel mouse desmoglein gene sharing high homology to both mouse and human Dsg1 . We propose to designate the previously published mouse Dsg1 gene as Dsg1- α and the new gene as Dsg1-β. Analysis of intron/exon organization of the Dsg1-α and Dsg1-β genes revealed significant conservation. The full-length mouse Dsg1-β cDNA contains an open reading frame of 3180 bp encoding a precursor protein of 1060 amino acids. Dsg1-β protein shares 94% and 76% identity with mouse Dsg1-α and human DSG1, respectively. RT-PCR using a multitissue cDNA panel demonstrated that while Dsg1-α mRNA was expressed in 15- to 17-day-old embryos and adult spleen and testis, Dsg1-β mRNA was detected in 17-day-old embryos only. To assess subcellular localization, a FLAG-tagged expression construct of Dsg1-β was transiently expressed in epithelial HaCaT cells. Dsg1-β-FLAG was found at the cell–cell border and was recognized by the anti-Dsg1/Dsg2 antibody DG3.10. In summary, we have cloned and characterized a novel member of the mouse desmoglein gene family, Dsg1-β. [ABSTRACT FROM AUTHOR]

Examines the characteristics of mouse desmogleins 1 (Dsg1) and desmogleins 2 (Dsg2), adhesion component of desmosomes. Messenger RNA expression patterns of desmogleins during mouse embryonic development; Expression of Dsg1 and Dsg2 in all developmental stage; Role in cell-cell adhesion during development.

We have made a derivative of bacteriophage λ that makes no OOP antisense RNA. The mutant phage carries a point mutation that inactivates the OOP promoter, Po. The phages λ+ and λPo¯ have identical plaque morphologies, one-step growth curves, and frequencies of lysogenization of a sensitive host. OOP RNA synthesis is weakly repressed by the Escherichia coli LexA protein. Consonant with this inducibility of OOP RNA synthesis by ultraviolet light, we find a two-fold greater phage burst following ultraviolet induction of a A than of a λPo¯ prophage. In λ+ infections, OOP RNA causes two cleavage events in cll mRNA: one is in the 3'-end of the coding region, and the second is in the intercistronic region between the cll and O genes. The cll gene fragments are subject to additional hydrolytic events, and cll mRNA levels are several-fold lower in λ+ than in λPo¯ infections late in the infection cycle. However, O mRNA levels are almost unaffected by the Po¯ mutation. [ABSTRACT FROM AUTHOR]

Objectives To review the incidence of testicular cancer within the Royal Air Force (RAF) compared with the national incidence. Methods The medical statistics for RAF personnel (supplied by the Central Statistics Office, categorized by occupation) were reviewed for the incidence of testicular cancer and compared to the national rate. Results A significantly elevated incidence of testicular neoplasm was detected in RAF personnel, which was well above the national rate. The increased incidence appeared most marked in those personnel working directly with aircraft. Conclusion The only cause of the significantly higher incidence of testicular cancer in RAF personnel is probably related to working with aircraft. This concurs with a finding that aircraft technicians in the US Navy had an increased incidence of testicular cancer, and the exposure to hydrocarbon carcinogens in the workplace was implicated. [ABSTRACT FROM AUTHOR]