Eigenvalues variations for Aharonov-Bohm operators

22 pagesWe study how the eigenvalues of a magnetic Schr{ö}dinger operator of Aharonov-Bohm type depend on the singularities of its magnetic potential. We consider a magnetic potential defined everywhere in $\mathbb{R}^2$ except at a finite number of singularities, so that the associated magnetic field is zero. On a fixed planar domain, we define the corresponding magnetic Hamiltonian with Dirichlet boundary conditions, and study its eigenvalues as functions of the singularities. We prove that these functions are continuous, and in some cases even analytic. We sketch the connection of this eigenvalue problem to the problem of finding spectral minimal partitions of the domain

Electrotonic Coupling in the Pituitary Supports the Hypothalamic-Pituitary-Gonadal Axis in a Sex Specific Manner

Gap junctions are present in many cell types throughout the animal kingdom and allow fast intercellular electrical and chemical communication between neighboring cells. Connexin-36 (Cx36), the major neuronal gap junction protein, synchronizes cellular activity in the brain, but also in other organs. Here we identify a sex-specific role for Cx36 within the hypothalamic-pituitary-gonadal (HPG) axis at the level of the anterior pituitary gland (AP). We show that Cx36 is expressed in gonadotropes of the AP sustaining their synchronous activity. Cx36 ablation affects the entire downstream HPG axis in females, but not in males. We demonstrate that Cx36-mediated coupling between gonadotropes in the AP supports gonadotropin-releasing hormone-induced secretion of luteinizing hormone. Furthermore, we provide evidence for negative feedback regulation of Cx36 expression in the AP by estradiol. We thus conclude that hormonally-controlled plasticity of gap junction communication at the level of the AP constitutes an additional mechanism affecting female reproduction

Multimodality imaging in marantic endocarditis associated with cancer: a multicentric cohort study

International audienceAims We aimed to assess the role of multimodality imaging (MMI) in the diagnosis of marantic endocarditis (ME) associated with cancers and to describe clinical characteristics, management, and outcome of these patients. Methods and results In a retrospective multicentric study including four tertiary centers for treatment of endocarditis in France and Belgium, patients with a diagnosis of ME were included. Demographic, MMI (echocardiography, computed tomography (CT) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F -FDG PET/CT) and management data were collected. Long-term mortality was analyzed. Between November 2011 and August 2021, 47 patients with a diagnosis of ME were included. Mean age was 65 +/- 11 years. ME occurred in 43 cases (91%) on native valves. Vegetations were detected by echocardiography in all cases and in 12 cases (26%) by CT. No patient had an increased cardiac 18F -FDG valve uptake. The most common cardiac valve involved was aortic (34 cases, 73%). 22 patients (46%) had a known cancer before ME and 25 cases (54%) were diagnosed thanks to multimodality imaging. 18-FDG PET/CT was performed in 30 patients (64%) and allowed a new diagnosis of cancer in 14 patients (30%). Systemic embolism was frequent (40 patients, 85% of cases). 41 patients (87%) were treated medically with anticoagulation therapy. One year mortality was 55% (26 patients). Conclusions ME remains associated with high risk of complications and death

FLT3L governs the development of partially overlapping hematopoietic lineages in humans and mice

International audienceFMS-related tyrosine kinase 3 ligand (FLT3L), encoded by FLT3LG, is a hematopoietic factor essential for the development of natural killer (NK) cells, B cells, and dendritic cells (DCs) in mice. We describe three humans homozygous for a loss-of-function FLT3LG variant with a history of various recurrent infections, including severe cutaneous warts. The patients' bone marrow (BM) was hypoplastic, with low levels of hematopoietic progenitors, particularly myeloid and B cell precursors. Counts of B cells, monocytes, and DCs were low in the patients' blood, whereas the other blood subsets, including NK cells, were affected only moderately, if at all. The patients had normal counts of Langerhans cells (LCs) and dermal macrophages in the skin but lacked dermal DCs. Thus, FLT3L is required for B cell and DC development in mice and humans. However, unlike its murine counterpart, human FLT3L is required for the development of monocytes but not NK cells