Genomic and phenotypic characterization of an atypical Aeromonas salmonicida strain isolated from a lumpfish and producing unusual granular structures.

Aeromonas salmonicida strains are roughly classified into two categories, typical and atypical strains. The latter mainly regroup isolates that present unusual phenotypes or hosts, comparatively to the typical strains that belong to the salmonicida subspecies. This study focuses on an uncharacterized atypical strain, M18076-11, isolated from lumpfish (Cyclopterus lumpus) and not part of the four recognized Aeromonas salmonicida subspecies. This isolate presents an unreported phenotype in the A. salmonicida species: the formation of large granular aggregates. Granules are formed of a heterogeneous mix of live and dead cells, with live cells composing the majority of the population. Even if no mechanism was determined to cause cellular aggregation, small globular structures at the cell surface were observed, which might affect granular formation. Pan-genome phylogenetic analysis indicated that this strain groups alongside the masoucida subspecies. However, phenotypic tests showed that these strains have diverging phenotypes, suggesting that M18076-11 might belong to a new subspecies. Also, a pAsal1-like plasmid, which was only reported in strains of the subspecies salmonicida, was discovered in M18076-11. This study sheds light on unsuspected diversity in A. salmonicida subspecies and stresses the need of thorough identification when a new strain is encountered, as unique traits might be discovered.

[Acute myocarditis revealing a pheochromocytoma]. / La myocardite aiguë, un mode de révélation peu fréquent du phéochromocytome Revue de la littérature à propos d'une observation.

We report a 29-year-old woman with an acute myocarditis documented by MRI as presenting manifestation of a pheochromocytoma, and we review the literature.

Echocardiographic assessment of the interventricular delay of activation and correlation to the QRS width in dilated cardiomyopathy.

The aim of the study was to define criteria for left ventricular pacing in dilated cardiomyopathy (DCM) using an echocardiographic evaluation of interventricular electromechanical delay (IMD) and a correlation of IMD to QRS duration. Standard 12-lead ECG and echocardiography with pulsed Doppler tissue imaging (DTI) were recorded in 35 DCM patients (mean age 58 +/- 11 years) with QRS duration from narrow (80 ms) to broad (222 ms) patterns. The timefor left ventricular activation was evaluated from the onset of QRS to the onset of aortic flow (Q-Ao) by standard pulsed Doppler (SP) or to the onset of mitral annulus systolic wave (Q-Mit) (DTI). The time for right ventricular activation was determinedfrom the onset of QRS to the onset of pulmonary flow (Q-Pulm) (SP) or to the onset of tricuspid annulus systolic wave (Q-Tri) (DTI). (Q-Ao)-(Q-Pulm) and (Q-Mit)-(Q-Tri) determined IMD for each method, respectively. QRS width and IMD showed correlation coefficients of r = 0.86 ([Q-Ao]-[Q-Pulm]) and r = 0.82 ([Q-Mit]-[Q-Tri]) (P < or = 0.001 ). Mean IMD of 77 +/- 15 ms (SP) and 88 +/- 26 ms (DTI) were noted for QRS width above 150 ms. Left ventricle delayed activation was positively correlated to QRS widening with both methods, (r = 0.90, [Q-Ao]), (r = 0.83, [Q-Mit]) (P < or = 0.001). In conclusion, QRS duration is a good marker of an interventricular mechanical asynchrony. According to IMD correction, left ventricular pacing may be mainly proposed to symptomatic DCM patients with QRS duration > 150 ms.

[Incidence and timing of thyroid dysfunction with long-term amiodarone therapy]. / Incidence et délai d'apparition des dysthyroïdies sous traitement chronique par amiodarone.

The aim of this retrospective study was to assess the incidence, timing and classical presentations of thyroid dysfunction in patients treated long-term with amiodarone. Ninety patients (sex ratio M/W 67/33, mean age 71 years) were followed up for 48 months. The daily dose of amiodarone was 200 mg after loading doses during the hospital stay for atrial fibrillation. The average treatment period was 33 +/- 19 months. Hypothyroidism, observed in 5.5% of cases, occurred at variable intervals with few clinical manifestations. Hyperthyroidism was more common (12.2%), occurred increasingly with time, and was clinically symptomatic with recurrent supraventricular arrhythmias in 36% of cases. Long-term amiodarone therapy causes undesirable thyroid side-effects for nearly 1 out of 5 patients. Hyperthyroidism is more common than hypothyroidism and may be explained by increased iodine intake. The increasing incidence of hyperthyroidism with time suggests a cumulated dose relationship, a situation which is not observed with hypothyroidism.

Transient ST segment elevation in right precordial leads induced by psychotropic drugs: relationship to the Brugada syndrome.

Psychotropic Drugs and ST Segment Elevation. Transient ST segment elevation in right precordial leads with use of psychotropic drugs is reported in two cases of overdose and one case of therapeutic administration. Flecainide did not reproduce ST segment elevation. The relationship of these abnormalities to the Brugada syndrome and the electrophysiologic hypothesis are discussed.

[MRI quantification of regional variations of left ventricular parietal stress in normal subjects]. / Quantification par imagerie par résonance magnétique des variations régionales de la contrainte pariétale du ventricule gauche chez le sujet normal.

The object of this study was to analyse regional variations in end systolic left ventricular wall stress in normal subjects using three-dimensional magnetic resonance imaging (MRI) with excellent spatial resolution. Eight to 12 contiguous short axis sections of the left ventricle were acquired from the apex to the base in apnoea with a rapid echo-gradient sequence in 15 healthy volunteers. The end systolic wall stress was calculated by three methods: Grossman's formula (CR) using the wall thickness and radius of curvature, Janz's formula (CS) using the surfaces, and a three-dimensional approach (C3D) providing a precise calculation of the radius of curvature. The values of wall stress obtained by CS and CR were lower (p < 0.001) at the apex (3.2 and 3.3 10(3) newton/m2 respectively) than at the base (6.9 and 7.1 10(3) newton/m2). There was no difference between the base and apex with the C3D method (8.0 and 9.0 10(3) newton/m2 respectively, NS). The same results were observed at the inferior, lateral, anterior and septal segments with an increase at the base using the CS and CR formulae, the C3D remaining homogeneous in the left ventricle except for the interventricular septum. The lateral wall stress was significantly lower with respect to the interventricular septum in all sections from the apex to the base, irrespective of the method of calculation used. The differences in regional wall stress from the base to the apex reported in healthy subjects seem to be related to an underestimation of left ventricular wall thickness and an underestimation of the radius of curvature rather than to a physiological phenomenon.

Regional assessment of wall curvature and wall stress in left ventricle with magnetic resonance imaging.

Left ventricular functional abnormalities are associated with regional increases of wall stress and modifications of wall curvature. This study describes the integration of the short-axis and long-axis wall curvatures for determining peak systolic wall stress. Quantification was realized with cine magnetic resonance imaging (MRI) from the location of the endocardial and epicardial borders of the left ventricle on pairs of consecutive short-axis sections. Fifteen normal volunteers were subjected to cine MRI, and different methods of calculating peak systolic wall stress were compared. A short-axis analysis showed a 55 +/- 13% increase of the circumferential mean of the peak systolic wall stress between apical and basal sections. Regarding the curvature, no significant increase of wall stress was observed except on the septal wall (31 +/- 18%). Short-axis studies proved to be insufficient for determining the regional variations of left ventricular wall stress and for providing normal reference values for the location of abnormal regions in patients.

Global left ventricular cardiac function: comparison between magnetic resonance imaging, radionuclide angiography, and contrast angiography.

RATIONALE AND OBJECTIVES: Cardiac magnetic resonance imaging (MRI) has been shown to be a robust and noninvasive method to assess left ventricular (LV) cardiac function. This study sought to assess volumes and mass calculated with MRI using fast techniques for acquisition and postprocessing, and to compare results in terms of cost-effectiveness with those of radionuclide angiography (RNA) or contrast angiography (CA). METHODS: Thirty-five patients and 15 healthy volunteers were studied. All patients underwent an MRI examination during the same period that they underwent ventriculography (26 patients) or radiography (25 patients). From 7 to 11 short-axis slices were acquired with a breath-hold fast-gradient echo-segmented sequence from apex to base. Contours were drawn with an automated border detection software. RESULTS: Ejection fraction (EF) correlated well between modalities (r = 0.77, P<0.001, for MRI and RNA; r = 0.72, P< 0.001, for MRI and CA). CONCLUSIONS: Cardiac MRI is a fast and accurate technique for estimation of LV volumes, EF, and mass.

[Measurement of the left ventricular mass using MRI with automatic determination of the endocardial and epicardial contours]. / Mesure de la masse ventriculaire gauche en IRM par détermination automatique des contours endocardiques et épicardiques.

This study describes a method of automatic border detection of the left ventricular endocardium and epicardium associating three methods of segmentation (increase of region, border detection and adaptive threshold), applicable to the evaluation of ventricular mass and volume by magnetic resonance imaging. Despite slight underestimation, the spin-echo sequence used in 9 small pigs provided a value of left ventricular mass close to that observed ex vivo (r = 0.97, SEE = 6.05 g). Clinical validation using a rapid gradient-echo sequence was undertaken and compared with manual border detection carried out by three independent, trained operators. The study population included healthy subjects and patients with global or segmental left ventricular dysfunction with or without ventricular deformation. The correlations between automatic and manual detection were satisfactory both for calculation of left ventricular mass (r = 0.93, SEE = 13 g) and measurement of surfaces (r = 0.91, SEE = 1.4 cm2). The concordance of the two methods was confirmed by the Bland and Altman test. Cardiac magnetic resonance imaging may provide accurate and reproducible measurements of left ventricular mass within acceptable acquisition and image processing times for routine use. Although the clinical value of such a method is accepted both for establishing the prognosis and guiding management, studies of the cost/efficacy ratio should be undertaken to situate magnetic resonance imaging with respect to other non-invasive techniques of investigation of left ventricular function.

Apparent segregation of null alleles ascribed to deletions of the ornithine transcarbamylase gene in congenital hyperammonaemia.

Ornithine transcarbamylase (OTC) deficiency is an X-linked disorder of the urea cycle mapped to chromosome Xp21.1. Here, we show that apparent segregation of null alleles at the OTC locus and flanking polymorphic loci mimicked false maternity or false paternity in three affected families. Based on these observations, we suggest giving consideration to gene deletion when dealing with segregation of null alleles in OTC deficiency.