Factors Determining the Restoration of Circadian Behavior by Hypothalamic Transplants

The expression of locomotor activity by golden hamsters is temporally controlled by circadian oscillators contained within the suprachiasmatic nucleus (SCN). A genetic mutation has been found that alters the freerunning period of the locomotor activity rhythm from the wild-type value of ~24 hours to ~20 hours in homozygous mutants. It has been shown previously that a transplant of fetal hypothalamic tissue containing the SCN to a host rendered arrhythmic by a complete lesion of the SCN restores rhythmicity with the freerunning period which is normally expressed by the donor genotype. To investigate the mechanisms by which the SCN controls the temporal organization of behavior, we made partial lesions to the SCN of hosts of one genotype, and then placed hypothalamic implants from fetal donors of a different genotype into the lesion site. By varying the size of the host's partial SCN lesion and the duration of time between lesioning and transplantation, we have attempted to alter the relative amount of host and donor control over the expression of locomotor activity. We found that the expression of donor rhythmicity requires the presence of a lesion to the host SCN, and that the incidence of donor expression increased as a function of host SCN lesion size. Neither the duration of time between lesioning and transplantation, nor the location of the transplant within the third ventricle had independent effects on the incidence of donor rhythm expression; however, there was a strong suggestion of an effect of their interaction

Prescription of bite-wing and panoramic radiographs in pediatric dental patients: An assessment of current trends and provider compliance

BACKGROUND: The aim of the authors was to evaluate prescription patterns for bite-wing and panoramic radiographs (PRs) for pediatric and adolescent dental patients after the implementation of the most recent guidelines from the American Dental Association and US Food and Drug Administration. METHODS: The authors accessed paid insurance claims data for all 50 states from January 1, 2013, through June 30, 2019, for patients 18 years and younger and extracted a 5% random sample population. The authors performed statistical analyses to evaluate various imaging metrics for pediatric dentists (PDs) and general practitioners (GPs). RESULTS: A total of 2,123,735 bite-wing images were ordered during 4,734,249 office visits. The average (standard deviation [SD]) time interval between bite-wing examinations ordered by GPs was 13.9 (7.4) months, and for PDs the average (SD) was 13.0 (6.7) months (P < .0001). When divided by age group, 3.5% of all bite-wings were obtained from patients aged 0 through 4 years. For PRs, the authors included 286,824 images in this study. The average (SD) time interval between PRs ordered for the same patient was 3.4 (1.3) years for PDs and 3.3 (1.4) years for GPs. One percent of all PRs were ordered for patients aged 0 through 4 years, with 403 images attributed to PDs and 2,348 to GPs. CONCLUSIONS: PDs were more likely to comply with the guidelines on radiograph prescriptions for pediatric and adolescent patients than GPs. PRACTICAL IMPLICATIONS: Inclusion of patient caries risk with insurance claims data could be considered for more appropriate administration of dental radiography. Future guidelines should be developed to include more explicit recommendations for prescribing PRs

Evolution of Melanopsin Photoreceptors: Discovery and Characterization of a New Melanopsin in Nonmammalian Vertebrates

In mammals, the melanopsin gene (Opn4) encodes a sensory photopigment that underpins newly discovered inner retinal photoreceptors. Since its first discovery in Xenopus laevis and subsequent description in humans and mice, melanopsin genes have been described in all vertebrate classes. Until now, all of these sequences have been considered representatives of a single orthologous gene (albeit with duplications in the teleost fish). Here, we describe the discovery and functional characterisation of a new melanopsin gene in fish, bird, and amphibian genomes, demonstrating that, in fact, the vertebrates have evolved two quite separate melanopsins. On the basis of sequence similarity, chromosomal localisation, and phylogeny, we identify our new melanopsins as the true orthologs of the melanopsin gene previously described in mammals and term this grouping Opn4m. By contrast, the previously published melanopsin genes in nonmammalian vertebrates represent a separate branch of the melanopsin family which we term Opn4x. RT-PCR analysis in chicken, zebrafish, and Xenopus identifies expression of both Opn4m and Opn4x genes in tissues known to be photosensitive (eye, brain, and skin). In the day-14 chicken eye, Opn4m mRNA is found in a subset of cells in the outer nuclear, inner nuclear, and ganglion cell layers, the vast majority of which also express Opn4x. Importantly, we show that a representative of the new melanopsins (chicken Opn4m) encodes a photosensory pigment capable of activating G protein signalling cascades in a light- and retinaldehyde-dependent manner under heterologous expression in Neuro-2a cells. A comprehensive in silico analysis of vertebrate genomes indicates that while most vertebrate species have both Opn4m and Opn4x genes, the latter is absent from eutherian and, possibly, marsupial mammals, lost in the course of their evolution as a result of chromosomal reorganisation. Thus, our findings show for the first time that nonmammalian vertebrates retain two quite separate melanopsin genes, while mammals have just one. These data raise important questions regarding the functional differences between Opn4x and Opn4m pigments, the associated adaptive advantages for most vertebrate species in retaining both melanopsins, and the implications for mammalian biology of lacking Opn4x

Electrochemically synthesized polymers in molecular imprinting for chemical sensing

This critical review describes a class of polymers prepared by electrochemical polymerization that employs the concept of molecular imprinting for chemical sensing. The principal focus is on both conducting and nonconducting polymers prepared by electropolymerization of electroactive functional monomers, such as pristine and derivatized pyrrole, aminophenylboronic acid, thiophene, porphyrin, aniline, phenylenediamine, phenol, and thiophenol. A critical evaluation of the literature on electrosynthesized molecularly imprinted polymers (MIPs) applied as recognition elements of chemical sensors is presented. The aim of this review is to highlight recent achievements in analytical applications of these MIPs, including present strategies of determination of different analytes as well as identification and solutions for problems encountered

Effects of circadian disruption on physiology and pathology: from bench to clinic (and back)

Nested within the hypothalamus, the suprachiasmatic nuclei (SCN) represent a central biological clock that regulates daily and circadian (i.e., close to 24 h) rhythms in mammals. Besides the SCN, a number of peripheral oscillators throughout the body control local rhythms and are usually kept in pace by the central clock. In order to represent an adaptive value, circadian rhythms must be entrained by environmental signals or zeitgebers, the main one being the daily light?dark (LD) cycle. The SCN adopt a stable phase relationship with the LD cycle that, when challenged, results in abrupt or chronic changes in overt rhythms and, in turn, in physiological, behavioral, and metabolic variables. Changes in entrainment, both acute and chronic, may have severe consequences in human performance and pathological outcome. Indeed, animal models of desynchronization have become a useful tool to understand such changes and to evaluate potential treatments in human subjects. Here we review a number of alterations in circadian entrainment, including jet lag, social jet lag (i.e., desynchronization between body rhythms and normal time schedules), shift work, and exposure to nocturnal light, both in human subjects and in laboratory animals. Finally, we focus on the health consequences related to circadian/entrainment disorders and propose a number of approaches for the management of circadian desynchronization.Fil: Chiesa, Juan José. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Duhart, José Manuel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Casiraghi, Leandro Pablo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Paladino, Natalia. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bussi, Ivana Leda. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Golombek, Diego Andrés. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Unmitigated agency and unmitigated communion: An analysis of the negative components of masculinity and femininity

The negative components of masculinity and femininity, conceptualized by Spence and her colleagues (1979) as unmitigated agency and unmitigated communion, were explored by examining dominant and submissive acts used in their expression. In three separate sessions, subjects (N=129) completed scales designed to measure these constructs, a Dominance Act Report, and a Submissiveness Act Report. Dominant acts used in the expression of unmitigated agency involved the formation of separations (e.g., making decisions without consulting the others involved in them), narcissistic self-assertion (e.g., telling others to perform one's menial tasks), and self-protection (e.g., bluffing one's way out of an embarrassing situation). Submissive acts used in the expression of unmitigated communion involved failing to make normatively appropriate agentic responses (e.g., walking out of a store knowing that one had been short-changed) and subjugating personal desires to group wishes (e.g., giving up vacation plans in deference to the preferences of others). Discussion focuses on elaborating the concepts of unmitigated agency and unmitigated communion.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45594/1/11199_2004_Article_BF00288234.pd