No abstract

Human placental stem villi (PSV) present contractile properties. In vitro mechanics were investigated in 40 human PSV. Contraction of PSV was induced by both KCl exposure (n = 20) and electrical tetanic stimulation (n = 20). Isotonic contractions were registered at several load levels ranging from zero-load up to isometric load. The tension-velocity relationship was found to be hyperbolic. This made it possible to apply the A. Huxley formalism for determining the rate constants for myosin cross-bridge (CB) attachment and detachment, CB single force, catalytic constant, myosin content, and maximum myosin ATPase activity. These molecular characteristics of myosin CBs did not differ under either KCl exposure or tetanus. A comparative approach was established from studies previously published in the literature and driven by mean of a similar method. As compared to that described in mammalian striated muscles, we showed that in human PSV, myosin CB rate constants for attachment and detachment were about 103 times lower whereas myosin ATPase activity was 105 times lower. Up to now, CB kinetics of contractile cells arranged along the long axis of the placental sheath appeared to be the slowest ever observed in any mammalian contractile tissue.

Background: Breast cancer may present genomic alterations leading to homologous recombination deficiency (HRD). PARP inhibitors have proven their efficacy in patients with HER2-negative (HER2-) metastatic breast cancer (mBC) harbouring germline (g) BRCA1/2 mutations in 3 phases III trials. The single-arm phase II RUBY trial included 42 patients, 40 of whom received at least one dose of rucaparib. RUBY study assessed the efficacy of rucaparib in HER2-mBC with either high genomic loss of heterozygosity (LOH) score or non-germline BRCA1/2 mutation. Patients and methods: The primary objective was the clinical benefit rate (CBR), and the study was powered to see 20% CBR using a 2-stage Simon design. Results: The primary-end point was not reached with a CBR of 13.5%. Two LOH-high patients, without somatic BRCA1/2 mutation, presented a complete and durable response (12 and 28.5 months). Whole-genome analysis was performed on 24 samples, including 5 patients who presented a clinical benefit from rucaparib. HRDetect tended to be associated with response to rucaparib, without reaching statistical significance (median HRDetect responders versus non-responders: 0.465 versus 0.040; p Z 0.2135). Finally, 220 of 711 patients with mBC screened for LOH upstream from RUBY presented a high LOH score associated with a higher likelihood of death (hazard ratio Z 1.39; 95% CI: 1.11e1.75; p Z 0.005). Conclusion: Our data suggest that a small subset of patients with high LOH scores without germline BRCA1/2 mutation could derive benefit from PARP inhibitors. However, the RUBY study underlines the need to develop additional biomarkers to identify selectively potential responders.

L'influence de Tubificidae du genre Tubifex sur le relargage des différentes formes du phosphore (particulaire, organique dissous et orihophosphates) a été étudiée au laboratoire, en conditions contrôlées. Lorsque le milieu est oxygéné, les vers entraînent une augmentation du phosphore particulaire dans la colonne d'eau mais aux dépens des orthophosphates, de sorte que le relargage de phosphore total n'est guère supérieur à celui du témoin. En milieu appauvri en oxygène, la différence est plus nette mais elle est surtout due au phosphore particulaire plus abondant. Ce phosphore particulaire semble provenir d'une agitation plus importante car la défécation est réduite par le déficit en oxygène. Le transfert apparent orthophosphates-phosphore particulaire pose le problème de la biodisponibilité de ce dernier qui conditionne l'action positive ou négative des Tubifex sur la nutrition algale.A laboratory study of the effect of Tubifex tubifex MiUI. (Tubificidae, Oligochaeta) on the release of phosphorus through the sediment

Locomotory and respiratory movements of Tubifex tubifex (Muller, 1774) were observed in aquaria by filming living worms and analysing the videotapes . Worm galleries formed a network and the tubificids moved in all directions in their muddy substratum . Over half stayed in the mud for about 2 minutes ; most stayed at the surface less than one hour. Many specimens were able to stay deep in the mud for more than five hours . The periodic return of tubificids to the surface, the duration of their stay there, the length of the body protuding from the mud and tail waving are a function of their respiratory needs .