Impact of prosthetic mitral rings on aortomitral apparatus function: a cardiac magnetic resonance imaging study.

BACKGROUND: The circumference of the aortic annulus adjusts proportionally with changes in left ventricular volume. These dimensional changes in the aortic annulus improve the left ventricular outflow tract (LVOT) hemodynamics and enhance the anterior mitral valve leaflet (AML) movement. In this study, we investigated the impact of circumferential and partial circumference prosthetic mitral rings on aortomitral apparatus function. METHODS: Forty patients who underwent coronary artery bypass graft surgery and restrictive annuloplasty of the mitral valve annulus through either a partial circumference flexible ring (group A = 20 patients) or a circumferential rigid ring (group B = 20 patients) were evaluated using cardiac magnetic resonance imaging. Imaging was performed at the end of a 2-year follow-up period. Variations in LVOT diameter, transmitral valve gradient, and effective mitral valve area were measured and compared. RESULTS: Mean variation in LVOT diameter was significantly higher in group A compared with group B (12.7% +/- 4% versus 3.6% +/- 5%, p = 0.0005). Transmitral valve gradient was higher in group B than in group A (6.2 +/- 3 mm Hg versus 4.6 +/- 2 mm Hg, p = 0.007), whereas effective mitral valve area was larger in group A than group B (3.9 +/- 4 cm(2) versus 3.1 +/- 6 cm(2), p = 0.009). The long-axis cardiac magnetic resonance imaging of patients in group B demonstrated that movement at the base of the AML was hindered with the AML pivotal point appearing to shift posteriorly. CONCLUSIONS: This study demonstrated that the use of circumferential annular rings significantly impairs overall aortomitral apparatus function by reducing outflow diameter and AML movement.

Evaluation of boldenone formation and related steroids transformations in veal faeces by liquid chromatography/tandem mass spectrometry.

It is established that bovine urine can result positive for boldenone and androstadienedione in consequence of faecal contamination. The simple transfer of steroids to urine is one minor aspect of faecal contamination. A high de novo production of steroids in faeces after deposition and in faeces-contaminated urine is almost certainly due to microbial activity, although the precursor compounds and transformations leading to the presence of these illegal steroids are unclear. We developed a simple in vitro method - incubation of faecal matter suspended in 0.9% saline - to induce steroid transformations in faeces, and analyzed the products by liquid chromatography/tandem mass spectrometry, without the need for prior extraction. Norethandrolone was the internal standard. The linearity (R(2): 0.987-0.999), sensitivity (LODs: 0.3 to 1.0 ng/mL; LOQs: 1.0 to 3.0 ng/mL), precision (intra-day CVs: 2.6-8.2; inter-day CVs: 4.5-11.5) and accuracy (percentage recovery: 89-120%) were calculated for the studied steroids. Androstenedione, androstadienedione, alpha- and beta-boldenone, testosterone and epitestosterone transformations were investigated. Mutual interconversion of steroids was observed, although 17beta-hydroxy steroids had low stability compared with 17alpha-hydroxy and 17-keto steroids. The results suggest that this simple in vitro system may be an effective way of studying hormone transformations in faeces and, after analogue studies, in faeces-contaminated urine.