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Pulmonary arterial hypertension (PAH) is a rare and severe disorder characterized by progressive pulmonary vasculopathy. Growth differentiation factor (GDF)2 encodes the pro‐protein bone morphogenetic protein (BMP) 9, activated after cleavage by endoproteases into an active mature form. BMP9, together with BMP10, are high‐affinity ligands of activin receptor‐like kinase 1 (ALK1) and BMP receptor type II (BMPR2). GDF2 mutations have been reported in idiopathic PAH with most patients being heterozygous carriers although rare homozygous cases have been described. The link between PAH occurrence and BMP9 or 10 expression level is still unclear. In this study, we describe a pediatric case of PAH also presenting with telangiectasias and epistaxis. The patient carries the novel homozygous GDF2 c.946A > G mutation, replacing the first arginine of BMP9's cleavage site (R316) by a glycine. We show that this mutation leads to an absence of circulating mature BMP9 and mature BMP9‐10 heterodimers in the patient's plasma although pro‐BMP9 is still detected at a similar level as controls. In vitro functional studies further demonstrated that the mutation R316G hampers the correct processing of BMP9, leading to the secretion of inactive pro‐BMP9. The heterozygous carriers of the variant were asymptomatic, similarly to previous reports, reinforcing the hypothesis of modifiers preventing/driving PAH development in heterozygous carriers. [ABSTRACT FROM AUTHOR]

STUDY QUESTIONS: Could anti-Miillerian hormone (AMH) mutations be implicated in the development of idiopathic premature ovarian insufficiency (POI)? SUMMARY ANSWER: Three rare or unknown missense variants of the AMH gene were identified in a cohort of 55 POI patients; all three variants showed a drastically reduced in vitro bioactivity. WHAT IS KNOWN ALREADY: Genetic factors are implicated in 5-15% of cases of POI. However, only a few genes have been shown to be involved in its development. AMH inhibits the recruitment of primordial follicles in the ovary and defective or absent AMH leads to premature depletion of the primordial follicle pool in AMH null mice. STUDY DESIGN, SIZE, DURATION: The whole coding sequence and the exon-intron junction of the AMH gene was sequenced in a cohort of 55 POI patients recruited over a period of 8 years. The studied variants were also sequenced in 197 ethnically matched controls. PARTICIPANTS/MATERIALS, SETTING, METHODS: POI was defined as amenorrhea of more than 4 months with increased FSH before the age of 40. Patients with POI resulting from radio- or chemotherapy, surgery, chromosomal anomalies or FMR1 gene pre-mutation were excluded from the study. Recombinant human wild-type (wt) and mutated AMH proteins were produced in HEK293 T cells. KK-1 cells transfected with the AMH receptor type 2 (AMHR2) and a BMP responsive element coupled to a luciferase reporter vector were stimulated with different concentrations of wt AMH and the three tested variants. MAIN RESULTS AND THE ROLE OF CHANCE: The whole coding sequence of the AMH gene could be performed and analyzed for 50 POI patients: 16 variants were found, including 6 missense variants from which 1 was unknown (R444H) and 2 were very rare (G264R and D288E). The variant D288E was also found in one ofthe patient's mother who also underwent POI at 32 years old. The stimulation of the AMH R2 assessed by the luciferase activity was drastically reduced for the three variants when compared with the wt AMH. LIMITATIONS, REASONS FOR CAUTION: The study is limited by a relatively small number of patients in the POI cohort. WIDER IMPLICATIONS OF THE FINDINGS: This is the first time that the bioactivity of AMH variants related to POI patients is tested in vitro. The functional study showed a drastic reduction of the protein activity for the three variants, supporting their contribution to the development of the ovarian insufficiency. The familial segregation further supports the implication of AMH in the development of POI. [ABSTRACT FROM AUTHOR]

The glycoprotein hormone receptor family is peculiar because, in contrast to other G protein-coupled receptors, a large N-terminal extracellular ectodomain is responsible for hormone recognition. Hormone-receptor pairs have evolved in such a manner that a limited number of positions both at the ‘seat-belt’ domain of the hormone and the leucine-rich repeats of the receptor, play attractive and repulsive interactions for binding and specificity, respectively. Surprisingly, the constitutive activity of the receptor, mostly modulated by highly conserved amino acids within the heptahelical domain of the receptor ( i.e., outside the hormone binding region), also regulates effectiveness of hormone recognition by the extracellular part. In this review we analyze, at the molecular level, these important discriminating determinants for selective binding of glycoprotein hormones to their receptors, as well as natural mutations, observed in patients with gestational hyperthyroidism or ovarian hyperstimulation syndrome, that modify the selectivity of binding. [ABSTRACT FROM AUTHOR]

The recent identification of mutations in the FSH receptor gene, which display an increased sensitivity to hCG and are responsible for the development of spontaneous ovarian hyperstimulation syndrome (OHSS), provides for the first time the molecular basis for the physiopathology of spontaneous OHSS. Based on these recent findings, this paper underlines the differences between spontaneous and iatrogenic OHSS and proposes a model to account for the different chronology between the two forms of the syndrome. In the iatrogenic form, the follicular recruitment and enlargement occur during ovarian stimulation with exogenous FSH, while in the spontaneous form, the follicular recruitment occurs later through the stimulation of the FSH receptor by pregnancy-derived hCG. In both forms, massive luteinization of enlarged stimulated ovaries ensues, inducing the release of vasoactive mediators, leading to the development of the symptoms of OHSS. [ABSTRACT FROM AUTHOR]

A Balb/c mouse was subjected to genetic immunization with a cDNA construct encoding the human thyrotropin receptor (TSHr). The immune response of the mouse resulted in the production of immunoglobulins recognizing the TSHr in three different assays: (1) flow immunocytometry (FACS) with CHO cells expressing the receptor; (2) receptor-dependent stimulation of cAMP production in the same cell line; and (3) competition with labeled TSH for binding to the receptor. One thousand hybridomas were generated from the spleen of the mouse and their supernatants were screened. A single monoclonal, IRI-SAb1, scored positive in all three assays and was studied further. It stimulated 13-fold cAMP production in TSHr-expressing CHO cells, with an EC50 in the low nanomolar range. When compared with bovine TSH, IRI-SAb1 behaved as a partial agonist. Contrary to the expectation from the characteristic of autoantibodies of Graves’ patients, IRI-SAb1 recognized a linear epitope, which was localized in a segment encompassing the first 281 residues of the receptor. [Copyright &y& Elsevier]

Abstract: This work is aimed at the numerical analysis of the vibration response of a plate, carrying one or more concentrated masses, under a stochastic, and convective load. The pressure load is a typical turbulent boundary layer excitation (TBL) and the structural configurations reproduce common experimental situations because the concentrated masses can be considered similar to accelerometer sensors. The models adopt the Corcos TBL model and the concentrated masses are simulated with the Dirac singularity function. The approximations, introduced with the above assumptions on the concentrated masses, and the necessary numerical accuracy, in calculating the structural responses, are discussed. The added masses do not lead to a relevant modification of the global structural response but, on the contrary, the results show that the local effects can be relevant: the paper highlights the differences of the vibration responses from the analogous structural configurations under a stochastic load without convective characteristics. [Copyright &y& Elsevier]

Spontaneous ovarian hyperstimulation syndrome (OHSS) is an extremely rare event. Normally OHSS is seen in the context of IVF. In 2003 a mutation of the FSH receptor (FSHR D567N) was identified for the first time as a cause of spontaneous OHSS. In most FSHR mutations, a hypersensitivity to human chorionic gonadotrophin (HCG) or thyroid-stimulating hormone (TSH) is described. This clinical case presents for the first time two occurrences of spontaneous OHSS in a single woman with a FSHR mutation and two different entities. Pathophysiology of both pregnancies was completely different. During the first pregnancy, elevated HCG and androgen concentrations led to spontaneous OHSS and finally to miscarriage. The second pregnancy with spontaneous OHSS was dominated by a latent hypothyroidism and normal HCG concentrations and ended in a delivery of a healthy female newborn. Due to the unusual courses of the pregnancies, the study looked for a mutation in the FSHR and surprisingly identified the same mutation previously described. This report confirms for the first time the in-vitro findings in a single clinical case that TSH as well as HCG leads to spontaneous OHSS in patients with FSHR D567N mutation. Hypothyroidism has to be treated or ruled out. [ABSTRACT FROM AUTHOR]