Sterility and Gene Expression in Hybrid Males of Xenopus laevis and X. muelleri

BACKGROUND: Reproductive isolation is a defining characteristic of populations that represent unique biological species, yet we know very little about the gene expression basis for reproductive isolation. The advent of powerful molecular biology tools provides the ability to identify genes involved in reproductive isolation and focuses attention on the molecular mechanisms that separate biological species. Herein we quantify the sterility pattern of hybrid males in African Clawed Frogs (Xenopus) and apply microarray analysis of the expression pattern found in testes to identify genes that are misexpressed in hybrid males relative to their two parental species (Xenopus laevis and X. muelleri). METHODOLOGY/PRINCIPAL FINDINGS: Phenotypic characteristics of spermatogenesis in sterile male hybrids (X. laevis x X. muelleri) were examined using a novel sperm assay that allowed quantification of live, dead, and undifferentiated sperm cells, the number of motile vs. immotile sperm, and sperm morphology. Hybrids exhibited a dramatically lower abundance of mature sperm relative to the parental species. Hybrid spermatozoa were larger in size and accompanied by numerous undifferentiated sperm cells. Microarray analysis of gene expression in testes was combined with a correction for sequence divergence derived from genomic hybridizations to identify candidate genes involved in the sterility phenotype. Analysis of the transcriptome revealed a striking asymmetric pattern of misexpression. There were only about 140 genes misexpressed in hybrids compared to X. laevis but nearly 4,000 genes misexpressed in hybrids compared to X. muelleri. CONCLUSIONS/SIGNIFICANCE: Our results provide an important correlation between phenotypic characteristics of sperm and gene expression in sterile hybrid males. The broad pattern of gene misexpression suggests intriguing mechanisms creating the dominance pattern of the X. laevis genome in hybrids. These findings significantly contribute to growing evidence for allelic dominance in hybrids and have implications for the mechanism of species differentiation at the transcriptome level

Exploring Referral and Service Utilization Patterns Within an Outpatient Interdisciplinary Pediatric Chronic Pain Program

Aimee K Hildenbrand,1– 3 Christina M Amaro,1,4 Benjamin Bear,1 Catherine M Soprano,3,5 Katherine S Salamon2,3 1Center for Healthcare Delivery Science, Nemours Children’s Health, Wilmington, DE, USA; 2Division of Behavioral Health, Nemours Children’s Hospital Delaware, Wilmington, DE, USA; 3Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA; 4Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA; 5Division of Diagnostic Referral, Nemours Children’s Hospital Delaware, Wilmington, DE, USACorrespondence: Aimee K Hildenbrand, Nemours Center for Healthcare Delivery Science, 1600 Rockland Road, RC-1, Suite 160, Wilmington, DE, 19803, USA, Tel +1 302 298 7874, Email [email protected]: We examine referral sources and clinical characteristics for youth presenting to an outpatient interdisciplinary pediatric chronic pain program.Patients and Methods: Referral data were extracted from the electronic health record. PROMIS Pediatric Anxiety and Pain Interference Scales were administered at an initial evaluation visit.Results: The program received 1488 referrals between 2016 and 2019, representing 1338 patients, with increasing volume of referrals over time. Referrals were primarily from orthopedics (19.6%), physical medicine and rehabilitation (18.8%), neurology (14.4%), and rheumatology (12.6%). Patients referred were primarily female (75.4%), White (80.1%), English-speaking (98.4%) adolescents (median=15.0 years). Of those referred, 732 (54.7%) attended an interdisciplinary evaluation (ie, with ≥ 2 disciplines). Adolescent anxiety was within the expected range by self-report (N=327, MT-score=55.67) and parent proxy-report (N=354, MT-score=57.70). Pain interference was moderately elevated by self-report (N=323, MT-score=61.52) and parent proxy-report (N=356, MT-score=64.02). There were no differences between patients referred who attended versus did not attend an interdisciplinary evaluation based on age, sex, ethnicity, or language. A smaller than expected proportion of referred Black patients (44%, P=0.02) and patients referred from orthopedics (40%) or pulmonology (11%) attended an evaluation, whereas a larger than expected proportion of those referred from physical medicine and rehabilitation (78%) were evaluated (P< 0.001).Conclusion: Results highlight the demand for outpatient interdisciplinary pediatric chronic pain treatment. Findings can inform decisions related to staffing and service design for pediatric hospitals that aim to establish or grow outpatient pediatric chronic pain programs.Keywords: chronic pain, interdisciplinary, pediatric, referral, treatmen

Transthyretin as a thyroid hormone carrier: function revisited

Thyroid hormones are essential for normal mammalian development and for normal metabolism. Thyroxine (T4) is the principal product synthesized by the thyroid follicles, and triiodothyronine (T3), the biologically active hormone, derives mainly from tissue T4 deiodination. More than 99% of the circulating hormone is bound to plasma proteins, mainly to thyroxine-binding globulin, transthyretin and albumin in man, and to transthyretin and albumin in rodents. The role of plasma proteins in the transport of hormones to target tissues has, for a long time, been controversial. The liver and the choroid plexus are the major sites of transthyretin synthesis, tissues from which transthyretin is secreted into the blood and the cerebrospinal fluid, respectively. Transthyretin has been proposed to mediate thyroid hormone transfer into the tissues, particularly into the brain across the choroid-plexus-cerebrospinal fluid barrier. Studies in a transthyretin-null mice strain have shown conclusively that transthyretin is not indespensable for thyroid hormones' entry into the brain and other tissues, nor for the maintenance of an euthyroid status. An euthyroid status is also observed in man totally deprived of thyroxine-binding globulin and in rats without albumin. Taken together, these results exclude dependence of thyroid hormone homeostasis on any major plasma carrier per se. This evidence agrees with the free hormone hypothesis which states that the biologically significant fraction, that is taken up by the tissues, is the free circulating hormone

Sources of Science Teaching Self-Efficacy for Preservice Elementary Teachers in Science Content Courses

Self-efficacy beliefs play a major role in determining teachers’ science teaching practices and have been a topic of great interest in the area of preservice science teacher education. This qualitative study investigated factors that influenced preservice elementary teachers’ science teaching self-efficacy beliefs in a physical science content course. The primary data sources included Science Teaching Efficacy Belief Instrument-B (STEBI-B) responses, two semi-structured interviews, classroom observations, and artifacts. Analysis of STEBI-B data was used to select 18 participants with varying levels of self-efficacy beliefs: low, medium, and high. Four categories representing course-related factors contributing towards participants’ science teaching self-efficacy beliefs were found: (1) enhanced science conceptual understandings, (2) active learning experiences, (3) teaching strategies, and (4) instructor as a role model. While some course elements such as hands-on learning experiences and inquiry-based teaching strategies seemed to impact all groups positively, the low-group participants were particularly benefited from the ways in which science concepts were presented and the pace at which learning progressed. One implication from this study is that science educators could include elements within science content courses to potentially support preservice teachers with varied initial levels of science teaching self-efficacy