Gravitational instability in a planet-forming disk.

The canonical theory for planet formation in circumstellar disks proposes that planets are grown from initially much smaller seeds. The long-considered alternative theory proposes that giant protoplanets can be formed directly from collapsing fragments of vast spiral arms induced by gravitational instability-if the disk is gravitationally unstable. For this to be possible, the disk must be massive compared with the central star: a disk-to-star mass ratio of 1:10 is widely held as the rough threshold for triggering gravitational instability, inciting substantial non-Keplerian dynamics and generating prominent spiral arms.

[Coronary artery disease risk stratification prior to kidney transplantation].

Patients with end-stage renal disease have a high risk of cardiovascular events, and are often referred for non-invasive screening prior to kidney transplantation. Several European and North American professional organizations have issued guidelines on what tests to perform and which patients may benefit most from them. There is some discrepancy between the various guidelines and their application varies broadly across medical centers and countries.

[Congenital heart diseases in clinical practice].

Congenital heart diseases are abnormalities in the heart's structure that are present at birth. Some are known to be associated with genetic disorders. They affect 8 out of every 1,000 newborns.

Left atrium reclassified: application of the American Society of Echocardiography/European Society of Cardiology cutoffs to unselected outpatients referred to the echocardiography laboratory.

Objectives: We sought to determine whether categorization of abnormal left atrial (LA) size based on volumes indexed to body surface area (LAVi) results in reclassification of LA dilatation if the classic antero-posterior diameter (LAd) was measured. The American Society of Echocardiography/European Society of Cardiology recommended LAVi over linear measurements and recently published cutoffs to qualify LA dilatation. However, many laboratories continue to use the LAd because it appears easier to measure.

Effects of progestins on estrogen-induced increase in C-reactive protein in postmenopausal women.

Background: C-reactive protein (CRP) represents an independent risk factor for coronary disease and stroke. Because oral estrogens increase CRP levels, with inflammatory and thrombotic consequences, we determined whether the co-administration of a progestin might modify the estrogenic effect on CRP.

Methods: In a non-randomized, non-blinded study, we measured C-reactive protein serum concentrations with high-sensitivity technique (hs-CRP) in 163 healthy postmenopausal women divided into groups as follow: 52 not taking hormones (referent group), and 111 taking hormone replacement therapy (HRT) (42 of whom treated with unopposed estrogen, and 69 with an estrogen/progestin combination).