Thyroid Hormone Controls the Onset of Androgen Sensitivity in the Developing Larynx ofXenopus laevis

AbstractGonadal differentiation, the onset of androgen-stimulated laryngeal growth and the genesis of a sex difference in laryngeal innervation, all temporally coincide with thyroid hormone (TH)-induced metamorphosis inXenopus laevis.To explore the role TH plays in the ontogeny of theXenopusandrogen-sensitive vocal neuromuscular system, we examined gonadal and laryngeal development in tadpoles in which metamorphosis had been blocked by treatment with the thyroxine synthesis inhibitor propylthiouracil (PTU). PTU treatment did not arrest gonadal differentiation. Testes from PTU-treated male tadpoles had seminiferous tubules and advanced stage male germ cells, while in females stage 1 oocytes were present. In contrast to the gonads, PTU did block morphological development of the larynx. Tadpoles treated with PTU for 50 or 100 days had larynges which structurally resembled those of stage 54 control tadpoles. PTU-treated animals did not exhibit the extensive development of the laryngeal cartilage seen in untreated animals. Laryngeal cartilages of hypothyroid tadpoles exhibited low density and minimal patterning of chondrocytes; the complex lumen and marked expansion of the dilator muscles characteristic of 50- and 100-day untreated animals were absent. Laryngeal growth evoked by exposure to exogenous androgen (dihydrotestosterone) was entirely prevented by PTU treatment. Hypothyroid tadpoles did not exhibit the decline in laryngeal nerve axon number characteristic of age-matched controls, nor were laryngeal nerve axon numbers sexually dimorphic. PTU treatment also interfered with the myelination of laryngeal axons. We conclude that while gonadal differentiation is independent of TH, androgen sensitive laryngeal development and sexually dimorphic laryngeal innervation require exposure to secreted TH

Issues in accelerometer methodology: the role of epoch length on estimates of physical activity and relationships with health outcomes in overweight, post-menopausal women

<p>Abstract</p> <p>Background</p> <p>Current accelerometer technology allows for data collection using brief time sampling intervals (i.e., epochs). The study aims were to examine the role of epoch length on physical activity estimates and subsequent relationships with clinically-meaningful health outcomes in post-menopausal women.</p> <p>Methods</p> <p>Data was obtained from the Woman On the Move through Activity and Nutrition Study (n = 102). Differences in activity estimates presented as 60s and 10s epochs were evaluated using paired t-tests. Relationships with health outcomes were examined using correlational and regression analyses to evaluate differences by epoch length.</p> <p>Results</p> <p>Inactivity, moderate- and vigorous-intensity activity (MVPA) were significantly higher and light-intensity activity was significantly lower (all <it>P </it>< 0.001) when presented as 10s epochs. The correlation between inactivity and self-reported physical activity was stronger with 10s estimates (<it>P </it>< 0.03); however, the regression slopes were not significantly different. Conversely, relationships between MVPA and body weight, BMI, whole body and trunk lean and fat mass, and femoral neck bone mineral density was stronger with 60s estimates (all <it>P </it>< 0.05); however, regression slopes were similar.</p> <p>Conclusion</p> <p>These findings suggest that although the use of a shorter time sampling interval may suggestively reduce misclassification error of physical activity estimates, associations with health outcomes did not yield strikingly different results. Additional studies are needed to further our understanding of the ways in which epoch length contributes to the ascertainment of physical activity in research studies.</p> <p>Trial Registration</p> <p>Clinical Trials Identifier: NCT00023543</p

The role of contextual constraints and chronic expectancies on behavior categorizations and dispositional inferences

The authors examined the roles of chronic expectancies and other contextual information in the dispositional inference process within the domain of ability judgments. Prior to viewing a videotaped performance under either cognitive load or no load, participants in Studies 1 and 2 were given additional information designed to constrain their categorizations of the performance. In Study 2, chronic future-event expectancies also were assessed. Analyses revealed that when under cognitive load, participants' ability inferences were assimilated to the constraint information (Studies 1 and 2) and to chronic expectancies (Study 2). Furthermore, Study 2 analyses revealed that these effects were mediated by participants' behavior categorizations. Evidence suggestive of a proceduralized form of correction for task difficulty (Studies 1 and 2) and an effortful, awareness-based correction for the constraint information and for chronic expectancies also was found. Results are examined in light of recent models of the dispositional inference process

COVID-19 related experiences among college students with and without disabilities: Psychosocial impacts, supports, and virtual learning environments

This cross-sectional analysis estimated differences, based on disability status, in college students' (n = 777) experiences during the COVID-19 pandemic. Data were modeled using t-tests and logistic regression. Most participants were white (86.2%), and women (66.4%). The mode age was 23. A third (35.6%) had at least one disability. Students reported high rates of psychosocial distress, like fear of contracting (59.7%) and spreading (74.3%) COVID-19, worry about friends and family (83.7%), and increased anxiety (72.5%), depression (59.9%), and substance use (24.7%). Forty-two percent (42.2%) were scared they would miss out on their education through virtual classes. About a third feared forgetting assignments (34.1%) and making mistakes (33.9%). Fewer students expressed apprehension about (27.9%) and intimidation by (26.3%) virtual learning. Only 17.2% would continue taking virtual classes after the pandemic. Students with disabilities (M = 12.4, SD = 4.1) experienced more psychosocial stressors compared to students without disabilities (M = 9.9, SD = 4.2), [t(775) = 7.86, p < 0.001]. In adjusted models, disabled students were more than twice as likely to experience worry about medical bills (OR = 2.29), loneliness (OR = 2.09), and increased anxiety (OR = 2.31). They were also more than three times as likely to report increased depression (OR = 3.51) and changes in sexual activity (OR = 3.12). However, students with disabilities (M = 1.5, SD = 1.1) also reported receiving more support compared to their non-disabled classmates (M = 1.1, SD = 1.1), [t(775) = 6.06, p < 0.001]. Disabled students were more likely to feel a sense of contributing to society by following precautions (OR = 1.80) and receive support from family and others (emotional support: OR = 2.01, financial support: OR = 2.04). Interestingly, no significant differences were found in students' feelings associated with online or virtual learning [t(526.08) = 0.42, p = 0.68]. Students with disabilities, though, trended toward reporting negative experiences with virtual learning. In conclusion, students with disabilities were disproportionately affected by COVID-19 stressors, but also expressed more support and a sense of contributing to the common good.Peer reviewedCommunity Health Sciences, Counseling and Counseling PsychologyEducational PsychologyIntegrative Biolog

Trust in and use of COVID-19 information sources differs by health literacy among college students

People’s health information-seeking behaviors differ by their health literacy levels. This study assessed the relationship between health literacy and college students’ levels of trust in and use of a range of health information sources of COVID-19. We collected data from August to December 2020 among college students (n = 763) through an online survey. We used a health literacy measure containing three self-reported survey questions, developed by the CDC. We assessed the extent to which participants trusted and used any of the sixteen different sources of information about COVID-19. Respondents reported high levels of trusting and using COVID-19 information from the CDC, health care providers, the WHO, state/county/city health departments, and official government websites when compared to other sources. After controlling for demographic characteristics (i.e., gender, age, race, ethnicity, and income), those who reported having lower health literacy were significantly less likely to trust and use COVID-19 information from these health authorities when compared to participants who reported having higher health literacy. Students with lower self-reported health literacy indicated not trusting or using official health authority sources for COVID-19 information. Relying on low-quality information sources could create and reinforce people’s misperceptions regarding the virus, leading to low compliance with COVID-19-related public health measures and poor health outcomes.Hlth Sci, Couns and Couns Psyc (HCCP

Probing forebrain to hindbrain circuit functions in Xenopus

journal articleThe vertebrate hindbrain includes neural circuits that govern essential functions including breathing, blood pressure and heart rate. Hindbrain circuits also participate in generating rhythmic motor patterns for vocalization. In most tetrapods, sound production is powered by expiration and the circuitry underlying vocalization and respiration must be linked. Perception and arousal are also linked; acoustic features of social communication sounds-for example, a baby's cry-can drive autonomic responses. The close links between autonomic functions that are essential for life and vocal expression have been a major in vivo experimental challenge. Xenopus provides an opportunity to address this challenge using an ex vivo preparation: an isolated brain that generates vocal and breathing patterns. The isolated brain allows identification and manipulation of hindbrain vocal circuits as well as their activation by forebrain circuits that receive sensory input, initiate motor patterns and control arousal. Advances in imaging technologies, coupled to the production of Xenopus lines expressing genetically encoded calcium sensors, provide powerful tools for imaging neuronal patterns in the entire fictively behaving brain, a goal of the BRAIN Initiative. Comparisons of neural circuit activity across species (comparative neuromics) with distinctive vocal patterns can identify conserved features, and thereby reveal essential functional component

Data from: Distinct neural and neuromuscular strategies underlie independent evolution of simplified advertisement calls

Independent or convergent evolution can underlie phenotypic similarity of derived behavioural characters. Determining the underlying neural and neuromuscular mechanisms sheds light on how these characters arose. One example of evolutionarily derived characters is a temporally simple advertisement call of male African clawed frogs (Xenopus) that arose at least twice independently from a more complex ancestral pattern. How did simplification occur in the vocal circuit? To distinguish shared from divergent mechanisms, we examined activity from the calling brain and vocal organ (larynx) in two species that independently evolved simplified calls. We find that each species uses distinct neural and neuromuscular strategies to produce the simplified calls. Isolated Xenopus borealis brains produce fictive vocal patterns that match temporal patterns of actual male calls; the larynx converts nerve activity faithfully into muscle contractions and single clicks. In contrast, fictive patterns from isolated Xenopus boumbaensis brains are short bursts of nerve activity; the isolated larynx requires stimulus bursts to produce a single click of sound. Thus, unlike X. borealis, the output of the X. boumbaensis hindbrain vocal pattern generator is an ancestral burst-type pattern, transformed by the larynx into single clicks. Temporally simple advertisement calls in genetically distant species of Xenopus have thus arisen independently via reconfigurations of central and peripheral vocal neuroeffectors