Collective movements, initiation and stops: diversity of situations and law of parsimony.

The environment of animals is often heterogeneous, containing zones that may be dedicated specifically to resting, drinking or feeding. These functional zones may spread over a more or a less extensive area. Thus, mobile animals may have to move from one patch to another when resources are locally depleted or when they need to change activity. The mechanisms involved in collective movement appear simple at first glance, but a brief reflection shows the real difficulty of the problem in terms of the numerous environmental, physical, physiological and social parameters involved. This review is mainly concerned with collective movements, which are characterised by a directional and temporal coordination, where individuals mutually influence each other, meaning this coordination mainly depends on social interactions (Huth and Wissel, 1992; Warburton and Lazarus, 1991; Couzin and Krause, 2003; Couzin et al., 2002). In literature, two types of movement are discussed: large-scale movement and small-scale movement. First, we define these types of movement and then discuss the behavioural mechanisms involved. Secondly, we show that short and long movement but also moving and stopping may result from the outcome of parameters modulation underpinning collective decision-making.

EgAP2-1, an AINTEGUMENTA-like (AIL) gene expressed in meristematic and proliferating tissues of embryos in oil palm.

In order to better understand the developmental processes that govern the formation of somatic embryos in oil palm (Elaeis guineensis Jacq.), we investigated the transcription factor genes expressed during embryogenesis in this species. The AP2/EREBP transcription factor family includes the AP2 subgroup, which contains several proteins that play important roles in plant development. We identified and characterized EgAP2-1, which codes for a protein that contains two AP2 domains similar to those of the transcription factor BABYBOOM (BBM) and more generally AINTEGUMENTA-like (AIL) proteins of the AP2 subgroup. In a similar way to related genes from eudicots, ectopic expression of EgAP2-1 in transgenic Arabidopsis plants alters leaf morphology and enhances regeneration capacity. In oil palm, EgAP2-1 transcripts accumulate to the greatest extent in zygotic embryos. This expression pattern was investigated in more detail by in-situ hybridization, revealing that in both zygotic and somatic embryos, EgAP2-1 expression is concentrated in proliferating tissues associated with the early development of leaf primordia, root initials and provascular tissues.

[Diverticulum of the right atrium. A case report and review of the literature]. / Diverticule de l'oreillette droite: description d'un cas et revue de la littérature.

Congenital atrial diverticula are rare, especially those involving the right atrium. This condition was observed in a 52 year old man who presented with palpitations. The diagnosis was made by two-dimensional echocardiography and confirmed by CT scan, magnetic resonance imaging and angiography. In the absence of significant invalidity, no treatment was recommended. Only three other cases of this condition have been previously reported, all of which were referred for surgery for thrombotic complications, arrhythmias and cardiac failure. Anatomo-pathological analysis showed different appearances: fibrous tissue and lipomatous degeneration. In the absence of associated heart disease, these aneurysms are probably congenital.

[Treatment of hypertension and cardiovascular complications]. / Traitement de l'hypertension artérielle et complications cardiovasculaires.

The three approaches (physiopathological, epidemiological and pharmacological) to the management of hypertension should converge to provide a personalized prescription of the most appropriate treatment to prevent and/or cure the cardiovascular complications of hypertension: hypertensive left ventricular hypertrophy and the risks directly related to it (haemodynamic, arrhythmic, ischaemic) may be corrected by certain antihypertensive agents (methyldopa, ACE inhibitors, some calcium antagonists) although there is no proof as yet of the benefits of this intervention (which could suppress the adaptation to the increased wall stress of the left ventricle); malignant hypertension and its cardiovascular complications have almost disappeared with modern antihypertensive therapy. Cardiac failure can be effectively prevented and cured when exclusively related to hypertension. When diastolic pressures are lowered by 8-10 mmHg cerebrovascular risk is reduced by a half and coronary risk by a quarter. Cardiovascular mortality related to hypertension is thus reduced by 20% and total mortality is thereby significantly decreased; the large scale clinical trials which provided these data were performed in the years 1965-1985 with diuretic therapy relayed by (or compared with) betablockers from 1980 onwards. These two families remain the drugs of reference in the prevention and treatment of the cardiovascular complications of hypertension. Personalized description of antihypertensive therapy should take into account the degree of risk and previous cardiovascular complications of the hypertensive patient: betablockers eventually associated with calcium antagonists are to be preferred in cases of hypertension with coronary artery disease and/or arrhythmias, severe hypertension and hypertension complicated by cardiac failure are good indications for ACE inhibitors without prejudicing other therapeutic options necessary in certain contexts, in particular aspirin therapy in patients with previous transient ischemic cerebral attacks.(ABSTRACT TRUNCATED AT 250 WORDS)

[Splenic calcification following cat scratch disease]. / Calcifications spléniques au décours d'une maladie des griffes du chat.

In a 9-year-old girl presenting with symptoms of cat scratch disease, ultrasound of the spleen showed multiple round hypoechogenic nodules which turned into calcifications within a year. Two years later, splenic calcifications were unchanged.

"Non-Q wave," alias "nontransmural," myocardial infarction: a specific entity.

Although Q wave and non-Q wave MI are often referred to as "transmural" and "nontransmural," there is no anatomic evidence to justify this distinction. Nevertheless, a distinction is important, because the two entities have a different prognosis. At the present time, between 25% and 35% of MIs are non-Q wave. They are frequently observed in patients with previous coronary events. They occur in a relatively older population and involve a slightly higher proportion of women than do Q wave MIs. The degree of cardiac damage is less, reflected by a smaller rise in enzyme level and less impairment of left ventricular ejection fraction; early reperfusion may occur, after spontaneous thrombolysis or resolution of coronary spasm. The immediate mortality rate is half that of Q wave MI but identical in the long term. Reinfarction and angina are more frequent because of a peri-infarction zone of ischemia maintained by a high-grade coronary stenosis and inadequate collateral circulation. Early characterization of those MIs likely to progress is important. Diltiazem seems effective in this context if given between 24 and 72 hours of the onset of the event. Other therapeutic approaches need further assessment.