Genomic selection for salinity tolerance in japonica rice

Improving plant performance in salinity-prone conditions is a significant challenge in breeding programs. Genomic selection is currently integrated into many plant breeding programs as a tool for increasing selection intensity and precision for complex traits and for reducing breeding cycle length. A rice reference panel (RP) of 241 Oryza sativa L. japonica accessions genotyped with 20,255 SNPs grown in control and mild salinity stress conditions was evaluated at the vegetative stage for eight morphological traits and ion mass fractions (Na and K). Weak to strong genotype-by-condition interactions were found for the traits considered. Cross-validation showed that the predictive ability of genomic prediction methods ranged from 0.25 to 0.64 for multi-environment models with morphological traits and from 0.05 to 0.40 for indices of stress response and ion mass fractions. The performances of a breeding population (BP) comprising 393 japonica accessions were predicted with models trained on the RP. For validation of the predictive performances of the models, a subset of 41 accessions was selected from the BP and phenotyped under the same experimental conditions as the RP. The predictive abilities estimated on this subset ranged from 0.00 to 0.66 for the multi-environment models, depending on the traits, and were strongly correlated with the predictive abilities on cross-validation in the RP in salt condition (r = 0.69). We show here that genomic selection is efficient for predicting the salt stress tolerance of breeding lines. Genomic selection could improve the efficiency of rice breeding strategies for salinity-prone environments.

Marker-Assisted Introgression of the Salinity Tolerance Locus Saltol in Temperate Japonica Rice

BACKGROUND

Rice is one of the most salt sensitive crops at seedling, early vegetative and reproductive stages. Varieties with salinity tolerance at seedling stage promote an efficient growth at early stages in salt affected soils, leading to healthy vegetative growth that protects crop yield. Saltol major QTL confers capacity to young rice plants growing under salt condition by maintaining a low Na⁺/K⁺ molar ratio in the shoots.

RESULTS

Marker-assisted backcross (MABC) procedure was adopted to transfer Saltol locus conferring salt tolerance at seedling stage from donor indica IR64-Saltol to two temperate japonica varieties, Vialone Nano and Onice. Forward and background selections were accomplished using polymorphic KASP markers and a final evaluation of genetic background recovery of the selected lines was conducted using 15,580 SNP markers obtained from Genotyping by Sequencing. Three MABC generations followed by two selfing, allowed the identification of introgression lines achieving a recovery of the recurrent parent (RP) genome up to 100% (based on KASP markers) or 98.97% (based on GBS). Lines with highest RP genome recovery (RPGR) were evaluated for agronomical-phenological traits in field under non-salinized conditions. VN1, VN4, O1 lines were selected considering the agronomic evaluations and the RPGR% results as the most interesting for commercial exploitation. A physiological characterization was conducted by evaluating salt tolerance under hydroponic conditions. The selected lines showed lower standard evaluation system (SES) scores: 62% of VN4, and 57% of O1 plants reaching SES 3 or SES 5 respectively, while only 40% of Vialone Nano and 25% of Onice plants recorded scores from 3 to 5, respectively. VN1, VN4 and O1 showed a reduced electrolyte leakage values, and limited negative effects on relative water content and shoot/root fresh weight ratio.

CONCLUSION

The Saltol locus was successfully transferred to two elite varieties by MABC in a time frame of three years. The application of background selection until BC₃F₃ allowed the selection of lines with a RPGR up to 98.97%. Physiological evaluations for the selected lines indicate an improved salinity tolerance at seedling stage. The results supported the effectiveness of the Saltol locus in temperate japonica and of the MABC procedure for recovering of the RP favorable traits.

Auxin triggers pectin modification during rootlet emergence in white lupin

Emergence of secondary roots through parental tissue is a highly controlled developmental process. Although the model plant Arabidopsis has been useful to uncover the predominant role of auxin in this process, its simple root structure is not representative of how emergence takes place in most plants, which display more complex root anatomy. White lupin is a legume crop producing structures called cluster roots, where closely spaced rootlets emerge synchronously. Rootlet primordia push their way through several cortical cell layers while maintaining the parent root integrity, reflecting more generally the lateral root emergence process in most multilayered species. In this study, we showed that lupin rootlet emergence is associated with an upregulation of cell wall pectin modifying and degrading genes under the active control of auxin. Among them, we identified LaPG3, a polygalacturonase gene typically expressed in cells surrounding the rootlet primordium and we showed that its downregulation delays emergence. Immunolabeling of pectin epitopes and their quantification uncovered a gradual pectin demethylesterification in the emergence zone, which was further enhanced by auxin treatment, revealing a direct hormonal control of cell wall properties. We also report rhamnogalacturonan-I modifications affecting cortical cells that undergo separation as a consequence of primordium outgrowth. In conclusion, we describe a model of how external tissues in front of rootlet primordia display cell wall modifications to allow for the passage of newly formed rootlets.

Dynamic Development of White Lupin Rootlets Along a Cluster Root

White lupin produces cluster roots in response to phosphorus deficiency. Along the cluster root, numerous short rootlets successively appear, creating a spatial and temporal gradient of developmental stages that constitutes a powerful biological model to study the dynamics of the structural and functional evolution of these organs. The present study proposes a fine histochemical, transcriptomic and functional analysis of the rootlet development from its emergence to its final length. Between these two stages, the tissue structures of the rootlets were observed, the course of transcript expressions for the genes differentially expressed was monitored and some physiological events linked to Pi nutrition were followed. A switch between (i) a growing phase, in which a normal apical meristem is present and (ii) a specialized phase for nutrition, in which the rootlet is completely differentiated, was highlighted. In the final stage of its determinate growth, the rootlet is an organ with a very active metabolism, especially for the solubilization and absorption of several nutrients. This work discusses how the transition between a growing to a determinate state in response to nutritional stresses is found in other species and underlines the fundamental dilemma of roots between soil exploration and soil exploitation.

Genetics of nodulation in Aeschynomene evenia uncovers mechanisms of the rhizobium-legume symbiosis

Among legumes (Fabaceae) capable of nitrogen-fixing nodulation, several Aeschynomene spp. use a unique symbiotic process that is independent of Nod factors and infection threads. They are also distinctive in developing root and stem nodules with photosynthetic bradyrhizobia. Despite the significance of these symbiotic features, their understanding remains limited. To overcome such limitations, we conduct genetic studies of nodulation in Aeschynomene evenia, supported by the development of a genome sequence for A. evenia and transcriptomic resources for 10 additional Aeschynomene spp. Comparative analysis of symbiotic genes substantiates singular mechanisms in the early and late nodulation steps. A forward genetic screen also shows that AeCRK, coding a receptor-like kinase, and the symbiotic signaling genes AePOLLUX, AeCCamK, AeCYCLOPS, AeNSP2, and AeNIN are required to trigger both root and stem nodulation. This work demonstrates the utility of the A. evenia model and provides a cornerstone to unravel mechanisms underlying the rhizobium-legume symbiosis.

Chitotetraose activates the fungal-dependent endosymbiotic signaling pathway in actinorhizal plant species

Mutualistic plant-microbe associations are widespread in natural ecosystems and have made major contributions throughout the evolutionary history of terrestrial plants. Amongst the most remarkable of these are the so-called root endosymbioses, resulting from the intracellular colonization of host tissues by either arbuscular mycorrhizal (AM) fungi or nitrogen-fixing bacteria that both provide key nutrients to the host in exchange for energy-rich photosynthates. Actinorhizal host plants, members of the Eurosid 1 clade, are able to associate with both AM fungi and nitrogen-fixing actinomycetes known as Frankia. Currently, little is known about the molecular signaling that allows these plants to recognize their fungal and bacterial partners. In this article, we describe the use of an in vivo Ca2+ reporter to identify symbiotic signaling responses to AM fungi in roots of both Casuarina glauca and Discaria trinervis, actinorhizal species with contrasting modes of Frankia colonization. This approach has revealed that, for both actinorhizal hosts, the short-chain chitin oligomer chitotetraose is able to mimic AM fungal exudates in activating the conserved symbiosis signaling pathway (CSSP) in epidermal root cells targeted by AM fungi. These results mirror findings in other AM host plants including legumes and the monocot rice. In addition, we show that chitotetraose is a more efficient elicitor of CSSP activation compared to AM fungal lipo-chitooligosaccharides. These findings reinforce the likely role of short-chain chitin oligomers during the initial stages of the AM association, and are discussed in relation to both our current knowledge about molecular signaling during Frankia recognition as well as the different microsymbiont root colonization mechanisms employed by actinorhizal hosts.

A phylogenetic framework of the legume genus Aeschynomene for comparative genetic analysis of the Nod-dependent and Nod-independent symbioses

BACKGROUND

Among semi-aquatic species of the legume genus Aeschynomene, some have the property of being nodulated by photosynthetic Bradyrhizobium lacking the nodABC genes necessary for the synthesis of Nod factors. Knowledge of the specificities underlying this Nod-independent symbiosis has been gained from the model legume Aeschynomene evenia but our understanding remains limited due to the lack of comparative genetics with related taxa using a Nod factor-dependent process. To fill this gap, we combined different approaches to perform a thorough comparative analysis in the genus Aeschynomene.

RESULTS

This study significantly broadened previous taxon sampling, including in allied genera, in order to construct a comprehensive phylogeny. In the phylogenetic tree, five main lineages were delineated, including a novel lineage, the Nod-independent clade and another one containing a polytomy that comprised several Aeschynomene groups and all the allied genera. This phylogeny was matched with data on chromosome number, genome size and low-copy nuclear gene sequences to reveal the diploid species and a polytomy containing mostly polyploid taxa. For these taxa, a single allopolyploid origin was inferred and the putative parental lineages were identified. Finally, nodulation tests with different Bradyrhizobium strains revealed new nodulation behaviours and the diploid species outside of the Nod-independent clade were compared for their experimental tractability and genetic diversity.

CONCLUSIONS

The extended knowledge of the genetics and biology of the different lineages sheds new light of the evolutionary history of the genus Aeschynomene and they provide a solid framework to exploit efficiently the diversity encountered in Aeschynomene legumes. Notably, our backbone tree contains all the species that are diploid and it clarifies the genetic relationships between the Nod-independent clade and the Nod-dependent lineages. This study enabled the identification of A. americana and A. patula as the most suitable species to undertake a comparative genetic study of the Nod-independent and Nod-dependent symbioses.

Cell remodeling and subtilase gene expression in the actinorhizal plant Discaria trinervis highlight host orchestration of intercellular Frankia colonization

Nitrogen-fixing filamentous Frankia colonize the root tissues of its actinorhizal host Discaria trinervis via an exclusively intercellular pathway. Here we present studies aimed at uncovering mechanisms associated with this little-researched mode of root entry, and in particular the extent to which the host plant is an active partner during this process. Detailed characterization of the expression patterns of infection-associated actinorhizal host genes has provided valuable tools to identify intercellular infection sites, thus allowing in vivo confocal microscopic studies of the early stages of Frankia colonization. The subtilisin-like serine protease gene Dt12, as well as its Casuarina glauca homolog Cg12, are specifically expressed at sites of Frankia intercellular colonization of D. trinervis outer root tissues. This is accompanied by nucleo-cytoplasmic reorganization in the adjacent host cells and major remodeling of the intercellular apoplastic compartment. These findings lead us to propose that the actinorhizal host plays a major role in modifying both the size and composition of the intercellular apoplast in order to accommodate the filamentous microsymbiont. The implications of these findings are discussed in the light of the analogies that can be made with the orchestrating role of host legumes during intracellular root hair colonization by nitrogen-fixing rhizobia.

Naturally occurring variations in the nod-independent model legume Aeschynomene evenia and relatives: a resource for nodulation genetics

BACKGROUND

Among semi-aquatic species of the legume genus Aeschynomene, some have the unique property of being root and stem-nodulated by photosynthetic Bradyrhizobium lacking the nodABC genes necessary for the production of Nod factors. These species provide an excellent biological system with which to explore the evolution of nodulation in legumes. Among them, Aeschynomene evenia has emerged as a model legume to undertake the genetic dissection of the so-called Nod-independent symbiosis. In addition to the genetic analysis of nodulation on a reference line, natural variation in a germplasm collection could also be surveyed to uncover genetic determinants of nodulation. To this aim, we investigated the patterns of genetic diversity in a collection of 226 Nod-independent Aeschynomene accessions.

RESULTS

A combination of phylogenetic analyses, comprising ITS and low-copy nuclear genes, along with cytogenetic experiments and artificial hybridizations revealed the richness of the Nod-independent Aeschynomene group with the identification of 13 diploid and 6 polyploid well-differentiated taxa. A set of 54 SSRs was used to further delineate taxon boundaries and to identify different genotypes. Patterns of microsatellite diversity also illuminated the genetic basis of the Aeschynomene taxa that were all found to be predominantly autogamous and with a predicted simple disomic inheritance, two attributes favorable for genetics. In addition, taxa displaying a pronounced genetic diversity, notably A. evenia, A. indica and A. sensitiva, were characterized by a clear geographically-based genetic structure and variations in root and stem nodulation.

CONCLUSION

A well-characterized germplasm collection now exists as a major genetic resource to thoroughly explore the natural variation of nodulation in response to different bradyrhizobial strains. Symbiotic polymorphisms are expected to be found notably in the induction of nodulation, in nitrogen fixation and also in stem nodulation. Subsequent genetic analysis and locus mapping will pave the way for the identification of the underlying genes through forward or reverse genetics. Such discoveries will significantly contribute to our understanding of the molecular mechanisms underpinning how some Aeschynomene species can be efficiently nodulated in a Nod-independent fashion.

The Casuarina NIN gene is transcriptionally activated throughout Frankia root infection as well as in response to bacterial diffusible signals

Root nodule symbioses (RNS) allow plants to acquire atmospheric nitrogen by establishing an intimate relationship with either rhizobia, the symbionts of legumes or Frankia in the case of actinorhizal plants. In legumes, NIN (Nodule INception) genes encode key transcription factors involved in nodulation. Here we report the characterization of CgNIN, a NIN gene from the actinorhizal tree Casuarina glauca using both phylogenetic analysis and transgenic plants expressing either ProCgNIN::reporter gene fusions or CgNIN RNAi constructs. We have found that CgNIN belongs to the same phylogenetic group as other symbiotic NIN genes and CgNIN is able to complement a legume nin mutant for the early steps of nodule development. CgNIN expression is correlated with infection by Frankia, including preinfection stages in developing root hairs, and is induced by culture supernatants. Knockdown mutants were impaired for nodulation and early root hair deformation responses were severely affected. However, no mycorrhizal phenotype was observed and no induction of CgNIN expression was detected in mycorrhizas. Our results indicate that elements specifically required for nodulation include NIN and possibly related gene networks derived from the nitrate signalling pathways.

[Mitral valve prolapse and angina with normal coronary arteries: research of a thrombogenic factor]

The potential thrombotic risk of mitral valve prolapse may, in certain circumstances, require preventive treatment. This study was aimed at determining whether the presence of angina in patients with mitral valve prolapse and healthy coronary vessels was accompanied by a high-risk thrombogenic profile. Forty two patients (19 women and 23 men) with anginal chest pain and angiographically normal coronary vessels were divided into two populations according to the presence (18 patients) or absence (24 patients) of mitral valve prolapse (MVP) shown by angiography. Before angiography, all patients underwent laboratory studies to detect any possible abnormality of plasma coagulation and of prothrombotic physiological fibrinolysis. Study of subgroups, according to sex and/or the presence of MVP, revealed no significant difference in the profile of laboratory parameters. Thus the presence of angiographic MVP in symptomatic patients free of atherosclerosis is not associated with the existence of any particular thrombotic profile and, theoretically, does not require preventive anti-thrombotic treatment.

Cardioprotective effect of trimetazidine in severe ischemic cardiomyopathy

The aim of this study was to assess the value of long-term treatment with 60 mg per day of trimetazidine, a cellular antiischemic agent, in comparison with placebo, in patients with ischemic cardiomyopathy controlled by conventional treatments. Twenty patients, with a mean age of 59.5 +/- 1.6 years, suffering from severe ischemic cardiomyopathy (NYHA IV, 6 patients; NYHA III, 14 patients) confirmed by coronary angiography, were included in the study; four of them suffered from residual angina. All of these patients were receiving long-term treatment with long-acting nitrates associated with digitalis (9 patients), diuretics (15 patients), anticoagulants (13 patients), and antiarrhythmics (11 patients), and were considered to be stabilized at the time of inclusion in the study. The examinations consisted of clinical and laboratory assessment, resting ECG, 24-hour ECG monitoring, X-ray evaluation of cardiac volume (CV), and evaluation of echocardiographic left ventricular shortening (ELVS) and of isotopic ejection fraction (EF). These three parameters were expressed as a percentage variation with respect to the initial value, and their variation between the two groups was compared by means of two-way analysis of variance. Clinically, the therapeutic benefit provided by trimetazidine resulted in: a) an improvement of dyspnea in all patients treated with trimetazicine compared with only one patient with placebo (p less than 0.001), b) resolution of residual angina, which was unchanged with placebo, c) reduced requirements for complementary treatments (a single case versus eight cases in the placebo group; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Therapeutic value of a cardioprotective agent in patients with severe ischaemic cardiomyopathy

Trimetazidine (TMZ) has been shown to have anti-ischaemic properties improving exercise tolerance without haemodynamic effects. A 6-month double-blind placebo-controlled study was carried out in 20 patients, mean age 59 +/- 6 years, to examine the benefit of adding 60 mg of TMZ vs placebo to the classical therapy, excluding those previously treated with calcium-antagonists, conversion enzyme inhibitors, vasodilators and antiplatelet agents. All patients had severe ischaemic cardiomyopathy, confirmed by coronary angiography; six were in NYHA class IV; 14 in NYHA class III; four had mild recurrent angina pectoris. assessment included clinical and biological evaluation, electrocardiography (ECG), 24-h ECG monitoring, cardiac volume evaluation with chest X-ray, left ventricular fractional shortening by echocardiography, left ventricular ejection fraction by radionuclide angiography. Baseline characteristics were similar in placebo (11 patients) and TMZ (nine patients) groups. Eighteen patients (nine in each group) were followed up for 6 months. In eight patients of the placebo group, treatment had to be modified (addition of calcium antagonists: four patients, conversion enzyme inhibitors: two patients; digitalics: one patient; diuretics: one patient). In the TMZ group, digitalic therapy was withdrawn in one patient and added in one patient (P less than 0.01). At 6 months, all TMZ group patients were free from angina; dyspnoea was improved in all TMZ patients and in only one placebo patient (P less than 0.001). Ejection fraction, increased by 9.3% in the TMZ group and decreased by 15.6% in the placebo group (P less than 0.018), CV decreased by 7% with TMZ, increased by 4% with placebo. (P = 0.034).(ABSTRACT TRUNCATED AT 250 WORDS)

[Low molecular weight heparin: an real alternative in thrombolysis in hemodialyzed patients. A trial of coronary thrombolysis]

Fibrinolytic treatments pose serious problems in subjects at high risk for hemorrhage, such as those requiring chronic dialysis. A 36-year-old patient requiring dialysis for the last 14 years due to chronic kidney failure was hospitalized for unstable angina combined with calcified mitral stricture. Prompt coronary arteriography revealed recent intracoronary thrombi. The failure of drug treatment and the surgical indication in light of unstable angina led the authors to use low-molecular-weight heparin b.i.d. for 12 days with monitoring of laboratory parameters (anti-Xa activity, APTT). No thrombotic or hemorrhagic episode was recorded. Control angiography indicating partial lysis of the left and right intracoronary thrombi led to exact evaluation of the residual underlying stenoses. A double aortocoronary bypass was subsequently performed combined with replacement of the mitral valve. This case gives a glimpse of the potential value of low-molecular-weight heparin as a valid alternative to conventional fibrinolysis in subjects requiring dialysis.

[Value of trimetazidine in the long-term treatment of cardiomyopathies of ischemic origin]

The effect of a cellular anti-ischemic, trimetazidine (TMZ) in ischemic cardiomyopathies, was evaluated in a double-blind versus-placebo (P) trial, over a period of six months. 20 patients, mean age: 59.5 years, with advanced ischemic cardiomyopathy, demonstrated by left catheterization and coronary angiography, with a past history of myocardial infarction, received either 60 mg per day of TMZ (nine patients) or the placebo (eleven patients) in addition to a basic treatment of digitalis, diuretics and nitrated medications. A complete, clinical, biological and paraclinical evaluation, including chest X-ray, ultrasonography, isotopic ventriculography and 24 h-ECG, was performed upon inclusion in the study; and after three and six months of treatment. Two patients from the placebo group were not reevaluated at six months. The clinical condition, according to the NYHA classification, improved in all patients from the TMZ group, deteriorated in eight on nine patients from the placebo group (p less than 0.001). The isotopic stroke volume is preserved with TMZ, deteriorated with P. The cardiac volume decreases with TMZ, increasing with P. TMZ is beneficial clinically and functionally in advanced ischemic cardiomyopathies.

[Metabolism of collagen in coronary patients]

The alterations observed in connective tissue of the arterial wall and dermis in atherosclerosis incited us to investigate collagen metabolism in patients with coronary disease. We first studied collagen metabolism in fibroblast cultures, then measured serum levels of type III procollagen aminoterminal peptide. Fibroblast collagen metabolism was investigated in 12 consecutive patients of less than 45 years of age presenting with coronary disease and coronary atherosclerosis was found to be preserved in patients with atherosclerosis, but less type III type I procollagen was synthesized (14.6 +/- 6.6% versus 22.3 +/- 4.3%). This abnormality, found in 83% of our coronary patients, seemed to be unrelated to risk factors or to the severity of atherosclerosis. Serum type III procollagen aminoterminal peptide was assayed comparatively in 36 patients with coronary atherosclerosis confirmed at coronary-ventriculography and in 35 patients free from coronary disease as defined by the W.H.O. criteria. Serum levels of this peptide were significantly higher in patients with coronary atherosclerosis (26.76 +/- 16 ng/ml) than in controls (10.43 +/- 3.18 ng/ml). 61% of coronary patients had a peptide level higher than the normal value (17 ng/ml). No correlation was found between this rise in type III procollagen aminoterminal peptide and the severity of coronary lesions or the importance of risk factors. Thus, collagen metabolism is altered in coronary patients, and this alteration can be detected by a peripheral marker. However, the use of this marker to diagnose the presence or evaluate the course of atherosclerosis requires clarification.

[Effectiveness of double fibrinolytic treatments in subacute deep vein thrombosis of the lower limbs]

The purpose of this study was to evaluate the effectiveness and desirability of a double fibrinolytic treatment in subacute venous thrombosis of the lower limbs. Thirty-four patients (mean age 55.2 +/- 15.4 years) hospitalized for thrombosis of deep lower limb veins were treated with two different fibrinolytic drugs administered successively: 23 patients received streptokinase first followed urokinase, and 11 patients received urokinase first followed by streptokinase. The overall results that improvement of the phlebographic score (Ph.s) was significantly greater in double fibrinolytic treatment (delta Ph.s. = 4.41 +/- 6.45, p less than 0.001) than after a single fibrinolytic treatment (delta Ph.s. = 3.14 +/- 4.76, p less than 0.001). Individual analysis of the results showed that 28% of the patients were improved by a second fibrinolytic treatment. It would appear that two fibrinolytic treatments are truly effective, albeit inconstantly and in most cases partially. We were unable in this study to determine the characteristics of patients likely to benefit from a double treatment.

[Sub-adventitial rupture of the popliteal artery and recurrent ischemia: a diagnostic pitfall in young patients]

In the absence of thromboembolic risk factors, signs of thrombosis in situ, or disorders of coagulation, two possible diagnoses must be envisaged when acute recurring ischemia is observed in a peripheral area of tissue: extrinsic compression or rupture of an arterial coat, especially when the subject is young and in good general health. The case of a 35 year old patient presenting with recurring ischemia in the popliteal artery of the right lower limb due to sub-adventitial rupture of the popliteal artery suggests three comments: the period of latency (3 months) between initial trauma to the popliteal artery and the operation of reverse saphenous vein bypass, the necessity for dynamic manipulations together with angiographic and ultrasound examination, the probable underestimation of the traumatic or functional causes of this disorder (popliteal artery), and the surgical prognosis remains excellent.

[Cardiac complications of dermatopolymyositis. Apropos of 56 cases]

A retrospective study was conducted on 58 patients hospitalized for dermato- or polymyositis between 1967 and 1986, with the view of determining the cardiovascular complications specific to these diseases. The patients' mean age was 51 years, less than 6 months had elapsed between first symptoms and diagnosis, and 31 p. 100 of the patients had died. The electrocardiogram was considered normal in 46 patients, none of whom presented with the slighted clinical evidence of cardiovascular involvement. ECG abnormalities were present in 10 cases, including 5 with disorders of conduction. Five cases of cardiovascular pathology with clinical manifestations were discovered. A 36-year old woman had severe myocardial pathology with marked rhabdomyolysis (CPK greater than 100,000) and complete atrio-ventricular block requiring emergency pacemaker implantation. Three years after the onset of the disease, and whilst the clinical signs of polymyositis had regressed, this patient still had complete AVB and moderately dilated congestive cardiomyopathy. This study shows that cardiac complications of dermato-polymyositis are rare and predominantly consist of disorders of conduction which may become permanent and associated with alterations of left ventricular kinetics. The authors suggest that a high-risk category for patients with disorders of conduction and cardiomyopathy can be identified by echocardiography, but this examination needs mainly be performed in cases when ECG abnormalities are present, since no clinical cardiac pathology was observed in patients of this series with normal electrocardiogram.

[Myocardial infarction, an unrecognized complication of Behçet's disease?]

It the vascular complications of Behcet's disease, especially thrombophlebitis, are well known, coronary involvement in seldom described (less than ten cases in the literature). The two cases reported here, of patients under 45, having presented both a myocardial infarction confirmed by coronary arteriography, lead to bring up first the problem of the causal relationship between disease and necrosis (inflammatory syndrome, thrombogenic tendency, vasospastic aspect), to reach a preventive attitude with, firstly, and extended use of anticoagulants in patients severely affected, in evolutive outbreaks, and then with the easier indication of anti-spastic treatments, mostly calcium blockers.

Prosthetic valve endocarditis: diagnosis and prognosis

From 1972 to 1982, 22 patients were admitted for prosthetic valve endocarditis on homografts (3), bioprostheses (2) or mechanical prostheses (17). Staphylococcus epidermidis was the most common aetiologic agent in early-onset endocarditis and streptococci in late-onset. Echo-cardiographic or cinefluoroscopic findings enhanced diagnosis mainly in advanced stages of the disease. Despite medical therapy and prompt reoperation in most cases, mortality remains high: 66%, 80% in the early group, 50% in the late group; the prognosis was definitely improved, however, by surgical treatment.