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Examines the changes in the histamine concentration in chicken oviduct during the egg-laying cycle. Determination of histamine concentration in the isthmus; Characterization of the oviduct of a laying hen; Profile of plasma sex steroid hormones.

Abstract: The present study was designed to (1) assess the role of triiodothyronine (T3) with regard to in vitro steroid hormone secretion by chicken ovarian follicles; (2) determine whether T3 influences the in vivo function of the pituitary-ovarian axis in the hen; and (3) detect expression of thyroid hormone receptor (TR) mRNA in chicken ovarian follicles. In the first experiment, laying hens were decapitated 22.5h before ovulation. White prehierarchical follicles (1–8mm) and fragments of theca and granulosa layers of the 3 largest yellow preovulatory follicles F3-F1 (22–35mm) were incubated in a medium supplemented with T3 (0, 0.1, 1, 10, 100, or 1000ng/mL) or ovine luteinizing hormone (LH) (10ng/mL) in combination with doses of T3 (1, 10, and 100ng/mL). Triiodothyronine decreased basal and LH-stimulated estradiol secretion by white follicles and the theca layer of all preovulatory follicles. On the other hand, it increased progesterone secretion by F2 and F1 follicles. In the second experiment, hens were injected 1h after ovulation with saline (control) or T3 (10μg/100g body weight, intraperitoneally). Results indicated that exogenous T3 decreased plasma concentrations of LH and estradiol and increased plasma concentrations of progesterone. In the third experiment, using reverse transcription polymerase chain reaction (RT-PCR) analysis, expression of thyroid hormone receptor (TRα and TRβ0), mRNA was detected in all of the ovarian compartments. The expression of TRα mRNA was relatively greater in comparison with TRβ0. There were no differences between white ovarian follicles in the expression of TRα and TRβ0 mRNA. A considerably higher TRα and lower TRβ0 expression was detected in the granulosa layer of preovulatory follicles in comparison with the theca layer. In conclusion, the data indicate that thyroid hormones acting via nuclear receptors are involved in regulation of the pituitary-ovarian axis and processes associated with follicle growth and maturation. [Copyright &y& Elsevier]

The term "recurrent constellations of embryonic malformations" (RCEM) is used to describe a number of multiple malformation associations that affect three or more body structures. The causes of these disorders are currently unknown, and no diagnostic marker has been identified. Consequently, providing a definitive diagnosis in suspected individuals is challenging. In this study, genome-wide DNA methylation analysis was conducted on DNA samples obtained from the peripheral blood of 53 individuals with RCEM characterized by clinical features recognized as VACTERL and/or oculoauriculovertebral spectrum association. We identified a common DNA methylation episignature in 40 out of the 53 individuals. Subsequently, a sensitive and specific binary classifier was developed based on the DNA methylation episignature. This classifier can facilitate the use of RCEM episignature as a diagnostic biomarker in a clinical setting. The study also investigated the functional correlation of RCEM DNA methylation relative to other genetic disorders with known episignatures, highlighting the common genomic regulatory pathways involved in the pathophysiology of RCEM., Competing Interests: Declaration of interests B.S. is a shareholder in EpiSign Inc. involved in commercial uses of EpiSign technology., (Copyright © 2024 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Context: Hyperinsulinemic hypoglycemia (HI) can be the presenting feature of Kabuki syndrome (KS), which is caused by loss-of-function variants in KMT2D or KDM6A. As these genes play a critical role in maintaining methylation status in chromatin, individuals with pathogenic variants have a disease-specific epigenomic profile -an episignature., Objective: We evaluated the pathogenicity of three novel partial KDM6A duplications identified in three individuals presenting with neonatal-onset HI without typical features of KS at the time of genetic testing., Methods: Three different partial KDM6A duplications were identified by routine targeted next generation sequencing for HI and initially classified as variants of uncertain significance (VUS) as their location, and hence their impact on the gene, was not known. Whole genome sequencing (WGS) was undertaken to map the breakpoints of the duplications with DNA methylation profiling performed in two individuals to investigate the presence of a KS-specific episignature., Results: WGS confirmed the duplication in proband 1 as pathogenic as it caused a frameshift in the normal copy of the gene leading to a premature termination codon. The duplications identified in probands 2 and 3 did not alter the reading frame and therefore their significance remained uncertain after WGS. Subsequent DNA methylation profiling identified a KS-specific episignature in proband 2 but not in proband 3., Conclusions: Our findings confirm a role for KDM6A partial gene duplications in the etiology of KS and highlight the importance of performing in-depth molecular genetic analysis to properly assess the clinical significance of VUS's in the KDM6A gene., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society.)

Analysis of genomic DNA methylation by generating epigenetic signature profiles (episignatures) is increasingly being implemented in genetic diagnosis. Here we report our experience using episignature analysis to resolve both uncomplicated and complex cases of neurodevelopmental disorders (NDDs). We analyzed 97 NDDs divided into (1) a validation cohort of 59 patients with likely pathogenic/pathogenic variants characterized by a known episignature and (2) a test cohort of 38 patients harboring variants of unknown significance or unidentified variants. The expected episignature was obtained in most cases with likely pathogenic/pathogenic variants (53/59 [90%]), a revealing exception being the overlapping profile of two SMARCB1 pathogenic variants with ARID1A/B:c.6200, confirmed by the overlapping clinical features. In the test cohort, five cases showed the expected episignature, including (1) novel pathogenic variants in ARID1B and BRWD3; (2) a deletion in ATRX causing MRXFH1 X-linked mental retardation; and (3) confirmed the clinical diagnosis of Cornelia de Lange (CdL) syndrome in mutation-negative CdL patients. Episignatures analysis of the in BAF complex components revealed novel functional protein interactions and common episignatures affecting homologous residues in highly conserved paralogous proteins (SMARCA2 M856V and SMARCA4 M866V). Finally, we also found sex-dependent episignatures in X-linked disorders. Implementation of episignature profiling is still in its early days, but with increasing utilization comes increasing awareness of the capacity of this methodology to help resolve the complex challenges of genetic diagnoses., Competing Interests: Declaration of interests B.S. is a shareholder in EpiSign Inc, company involved in commercialization of EpiSign technology., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)