Hypothalamic-pituitary-adrenal axis activity is not elevated in a songbird (Junco hyemalis) preparing for migration.

During spring, increasing daylengths stimulate gonadal development in migratory birds. However, late-stage reproductive development is typically postponed until migration has been completed. The hypothalamic-pituitary-adrenal (HPA) axis regulates the secretion of glucocorticoids, which have been associated with pre-migratory hyperphagia and fattening. The HPA-axis is also known to suppress the hypothalamic-pituitary-gonadal (HPG) axis, suggesting the possibility that final transition into the breeding life history stage may be slowed by glucocorticoids. We hypothesized that greater HPA-axis activity in individuals preparing for migration may foster preparation for migration while simultaneously acting as a "brake" on the development of the HPG-axis. To test this hypothesis, we sampled baseline corticosterone (CORT), stress-induced CORT, and negative feedback efficacy of Dark-eyed Juncos (Junco hyemalis) in an overwintering population that included both migratory (J.h. hyemalis) and resident (J.h. carolinensis) individuals. We predicted that compared to residents, migrants would have higher baseline CORT, higher stress-induced CORT, and weaker negative feedback. Juncos were sampled in western Virginia in early March, which was about 2-4wk before migratory departure for migrants and 4-5wk before first clutch initiation for residents. Contrary to our predictions, we found that migrants had lower baseline and stress-induced CORT and similar negative feedback efficacy compared with residents, which suggests that delayed breeding in migrants is influenced by other physiological mechanisms. Our findings also suggest that baseline CORT is not elevated during pre-migratory fattening, as migrants had lower baseline CORT and were fatter than residents.

Nucleus basalis-enabled stimulus-specific plasticity in the visual cortex is mediated by astrocytes.

Although cholinergic innervation of the cortex by the nucleus basalis (NB) is known to modulate cortical neuronal responses and instruct cortical plasticity, little is known about the underlying cellular mechanisms. Using cell-attached recordings in vivo, we demonstrate that electrical stimulation of the NB, paired with visual stimulation, can induce significant potentiation of visual responses in excitatory neurons of the primary visual cortex in mice. We further show with in vivo two-photon calcium imaging, ex vivo calcium imaging, and whole-cell recordings that this pairing-induced potentiation is mediated by direct cholinergic activation of primary visual cortex astrocytes via muscarinic AChRs. The potentiation is absent in conditional inositol 1,4,5 trisphosphate receptor type 2 KO mice, which lack astrocyte calcium activation, and is stimulus-specific, because pairing NB stimulation with a specific visual orientation reveals a highly selective potentiation of responses to the paired orientation compared with unpaired orientations. Collectively, these findings reveal a unique and surprising role for astrocytes in NB-induced stimulus-specific plasticity in the cerebral cortex.

Impact of preoperative respiratory distress on outcomes of slide tracheoplasty.

OBJECTIVES: Children with congenital tracheal stenosis born in the developing world face a high risk of mortality due to limited access to proper treatment. Patients who required preoperative respiratory support were suspected to have poor survival after slide tracheoplasty; however, this was not clearly demonstrated in the previous studies. This study aims to investigate the impact of preoperative respiratory conditions on outcomes of slide tracheoplasty. METHODS: From 2016 to 2022, children who underwent slide tracheoplasty were retrospectively reviewed. Patients with respiratory distress requiring emergency operations (group A) were compared with patients in stable condition who were scheduled for surgery (group B). RESULTS: Perioperative results revealed that group A (n = 43) had a longer bypass time (P < 0.001), operation time (P = 0.01), postoperative ventilation time (P < 0.001) and length of intensive care unit stay (P = 0.00125) than group B (n = 60). The early mortality rate was 7.8%, and the actuarial 5-year survival rate was 85.3%. The cumulative incidence test revealed that group A was highly significant for overall mortality [sudistribution (SHR) 4.5; 95% confidence interval (CI) 1.23-16.4; P = 0.023]. Risk factors for overall mortality were prolonged postoperative ventilation time (hazard ratio 3.86; 95% CI 1.20-12.48; P = 0.024), bronchial stenosis (hazard ratio 5.77; 95% CI 1.72-19.31; P = 0.004), and preoperative tracheal mucositis (hazard ratio 5.67; 95% CI 1.51-21.31; P = 0.01). Four patients needed reintervention during a follow-up of 28.4 months (interquartile range 15.3-47.3). CONCLUSIONS: Preoperative respiratory distress negatively affected the outcomes of patients who required slide tracheoplasty. Therefore, early detection of congenital tracheal stenosis and aggressive slide tracheoplasty are crucial and obligatory to enhance long-term survival in this lethal congenital airway disease.

Lactobacillus rhamnosus Infective Endocarditis in an Elderly Male.

Lactobacilli are facultative anaerobic, gram-positive, rod-shaped bacteria found in the normal flora of the oral cavity and the gastrointestinal and genitourinary tracts. This report presents a case of Lactobacillus rhamnosus infective endocarditis and provides echocardiographic evidence of its pathogenic potential. Furthermore, we provide an account of the first successful treatment with daptomycin to our knowledge. Additionally, we examine the limited literature available on this microbiological entity and attempt to relate this data to our case.

miR-132, an experience-dependent microRNA, is essential for visual cortex plasticity.

Using quantitative analyses, we identified microRNAs (miRNAs) that were abundantly expressed in visual cortex and that responded to dark rearing and/or monocular deprivation. The most substantially altered miRNA, miR-132, was rapidly upregulated after eye opening and was delayed by dark rearing. In vivo inhibition of miR-132 in mice prevented ocular dominance plasticity in identified neurons following monocular deprivation and affected the maturation of dendritic spines, demonstrating its critical role in the plasticity of visual cortex circuits.