Abrupt change of Antarctic moisture origin at the end of Termination II.

The deuterium excess of polar ice cores documents past changes in evaporation conditions and moisture origin. New data obtained from the European Project for Ice Coring in Antarctica Dome C East Antarctic ice core provide new insights on the sequence of events involved in Termination II, the transition between the penultimate glacial and interglacial periods. This termination is marked by a north-south seesaw behavior, with first a slow methane concentration rise associated with a strong Antarctic temperature warming and a slow deuterium excess rise. This first step is followed by an abrupt north Atlantic warming, an abrupt resumption of the East Asian summer monsoon, a sharp methane rise, and a CO(2) overshoot, which coincide within dating uncertainties with the end of Antarctic optimum. Here, we show that this second phase is marked by a very sharp Dome C centennial deuterium excess rise, revealing abrupt reorganization of atmospheric circulation in the southern Indian Ocean sector.

Predicting activities without computing descriptors: graph machines for QSAR.

We describe graph machines, an alternative approach to traditional machine-learning-based QSAR, which circumvents the problem of designing, computing and selecting molecular descriptors. In that approach, which is similar in spirit to recursive networks, molecules are considered as structured data, represented as graphs. For each example of the data set, a mathematical function (graph machine) is built, whose structure reflects the structure of the molecule under consideration; it is the combination of identical parameterised functions, called "node functions" (e.g. a feedforward neural network). The parameters of the node functions, shared both within and across the graph machines, are adjusted during training with the "shared weights" technique. Model selection is then performed by traditional cross-validation. Therefore, the designer's main task consists in finding the optimal complexity for the node function. The efficiency of this new approach has been demonstrated in many QSAR or QSPR tasks, as well as in modelling the activities of complex chemicals (e.g. the toxicity of a family of phenols or the anti-HIV activities of HEPT derivatives). It generally outperforms traditional techniques without requiring the selection and computation of descriptors.

A Pleistocene ice core record of atmospheric O2 concentrations.

The history of atmospheric O2 partial pressures (Po2) is inextricably linked to the coevolution of life and Earth's biogeochemical cycles. Reconstructions of past Po2 rely on models and proxies but often markedly disagree. We present a record of Po2 reconstructed using O2/N2 ratios from ancient air trapped in ice. This record indicates that Po2 declined by 7 per mil (0.7%) over the past 800,000 years, requiring that O2 sinks were ~2% larger than sources. This decline is consistent with changes in burial and weathering fluxes of organic carbon and pyrite driven by either Neogene cooling or increasing Pleistocene erosion rates. The 800,000-year record of steady average carbon dioxide partial pressures (Pco2) but declining Po2 provides distinctive evidence that a silicate weathering feedback stabilizes Pco2 on million-year time scales.

Interaction of FliI, a component of the flagellar export apparatus, with flagellin and hook protein.

FliI is a key component of the flagellar export apparatus in Salmonella typhimurium. It catalyzes the hydrolysis of ATP which is necessary for flagellar assembly. Affinity blotting experiments showed that purified flagellin and hook protein, two flagellar axial proteins, interact specifically with FliI. The interaction of either of the two proteins with FliI, increases the intrinsic ATPase activity. The presence of either flagellin or hook protein stimulates ATPase activity in a specific and reversible manner. A Vmax of 0.12 nmol Pi min-1 microgram-1 and a Km for MgATP of 0.35 mM was determined for the unstimulated FliI; the presence of flagellin increased the Vmax to 0.35 nmol Pi min-1 microgram-1 and the Km for MgATP to 1.1 mM. The stimulation induced by the axial proteins was fully reversible suggesting a direct link between the catalytic activity of FliI and the export process.

Characterization of the alpha and beta-subunits of the F0F1-ATPase from the alga Polytomella spp., a colorless relative of Chlamydomonas reinhardtii.

The isolation and partial characterization of the oligomycin-sensitive F0F1-ATP synthase/ATPase from the colorless alga Polytomella spp. is described. Purification was performed by solubilization with dodecyl-beta-D-maltoside followed by Sepharose Hexyl ammonium chromatography, a matrix that interacts with the F1 sector of mitochondrial ATPases. The alpha-subunit, which migrates on SDS-polyacrylamide gels with an apparent molecular mass of 55 kDa, was identified by the N-terminal sequencing of 47 residues. This subunit exhibited a short extension at its N-terminus highly similar to the one described for the unicellular alga Chlamydomonas reinhardtii (Nurani, G. and Franzén L.-G. (1996) Plant Mol. Biol. 31, 1105-1116). In whole mitochondria, the alpha-subunit was susceptible to limited proteolytic digestion induced by heat. An endogenous protease removed the first 22 residues of the mature alpha-subunit. Subunit beta was also identified by N-terminal sequencing of 31 residues. This subunit of 63 kDa exhibited a higher apparent molecular mass than alpha, as judged by its mobility on denaturing polyacrylamide gel electrophoresis. This beta-subunit is 7-8 kDa larger than the beta-subunits of other mitochondrial ATPases. It is suggested that the beta-subunit from Polytomella spp. may have a C-terminal extension similar to that described for the green alga C. reinhardtii (Franzén, L.-G. and Falk, G.(1992) Plant Mol. Biol. 19, 771-780). In addition, it was found that the C-terminal extension of the beta-subunit of C. reinhardtii showed homology with the endogenous ATPase inhibitors from various sources and with the epsilon-subunit from the F0F1-ATP synthase from Escherichia coli, which is considered to be a functional homolog of the inhibitor proteins. The data reported here provide the first biochemical evidence for a close relationship between the colorless alga Polytomella spp. and its photosynthetic counterpart C. reinhardtii. It is also suggested that the C-terminal extensions of the beta-subunits of the ATP synthases from these algae, may play a regulatory role in these enzymes.

Unisite ATP hydrolysis by soluble Rhodospirillum rubrum F1-ATPase is accelerated by Ca2+

At saturating concentrations of ATP, soluble F1 from the Rhodospirillum rubrum (RF1) exhibits a higher rate of hydrolysis with Ca2+ than with Mg2+. The mechanisms involved in the expression of a higher catalytic activity with Ca2+ were explored by measuring the ATPase activity of RF1 at substiochiometric concentrations of ATP (unisite conditions). At a ratio of 0.25 [gamma-32P]ATP per RF1, the enzyme exhibited a 50 times higher hydrolytic rate with Ca2+ than with Mg2+. The rate of [gamma-32P]ATP binding to RF1 was in the same range with the two divalent metal ions. Centrifugation-filtration of RF1 exposed to substoichiometric [gamma-32P]ATP concentrations and Mg2+ through Sephadex columns yielded an enzyme that contained [gamma-32P]ATP and [32P]phosphate in a stoichiometry that was close to one. In the presence of Ca2+, the eluted enzyme did not contain [gamma-32P]ATP nor [32P]phosphate. This indicated that the rate of product release was faster with Ca2+ than with Mg2+. It was also observed that the ratio of multisite to unisite hydrolysis rates was of similar magnitude with both divalent cations. This suggests that they do not affect differently the cooperative mechanisms that may exist between catalytic sites. In consequence, the higher ATPase activity of RF1 in presence of Ca2+ strongly suggests that the retention time of products is decreased in the presence of this cation. Copyright 1998 Elsevier Science B.V.

Cardiac metaiodobenzylguanidine uptake in patients with moderate chronic heart failure: relationship with peak oxygen uptake and prognosis.

OBJECTIVES: This prospective study was undertaken to correlate early and late metaiodobenzylguanidine (MIBG) cardiac uptake with cardiac hemodynamics and exercise capacity in patients with heart failure and to compare their prognostic values with that of peak oxygen uptake (VO2). BACKGROUND: The cardiac fixation of MIBG reflects presynaptic uptake and is reduced in heart failure. Whether it is related to exercise capacity and has better prognostic value than peak VO2 is unknown. METHODS: Ninety-three patients with heart failure (ejection fraction <45%) were studied with planar MIBG imaging, cardiopulmonary exercise tests and hemodynamics (n = 44). Early (20 min) and late (4 h) MIBG acquisition, as well as their ratio (washout, WO) were determined. Prognostic value was assessed by survival curves (Kaplan-Meier method) and uni- and multivariate Cox analyses. RESULTS: Late cardiac MIBG uptake was reduced (131+/-20%, normal values 192+/-42%) and correlated with ejection fraction (r = 0.49), cardiac index (r = 0.40) and pulmonary wedge pressure (r = -0.35). There was a significant correlation between peak VO2 and MIBG uptake (r = 0.41, p < 0.0001). With a mean follow-up of 10+/-8 months, both late MIBG uptake (p = 0.04) and peak VO2 (p < 0.0001) were predictive of death or heart transplantation, but only peak VO2 emerged by multivariate analysis. Neither early MIBG uptake nor WO yielded significant insights beyond those provided by late MIBG uptake. CONCLUSIONS: Metaiodobenzylguanidine uptake has prognostic value in patients with wide ranges of heart failure, but peak VO2 remains the most powerful prognostic index.

Effect of systemic hypertension on renal function and left ventricular hypertrophy in heart transplant recipients.

To evaluate the incidence, risk factors and effects of systemic hypertension on renal function and left ventricular hypertrophy after cardiac transplantation, 85 transplant recipients on triple drug, low dosage, immunosuppressive therapy were studied. After a mean follow-up period of 12.5 +/- 8.7 months, a high incidence of hypertension was observed in 57 (67%) of the patients, and 42 (71%) of the 57 had developed new hypertension. None of the pretransplant and posttransplant cardiovascular risk factors were significantly associated with posttransplant hypertension. Faster deterioration of renal function, as assessed by intraindividual variations of serum creatinine values, was demonstrated in hypertensive patients and appeared as an early indicator of cyclosporine nephrotoxicity in patients at risk for hypertension. Serial echocardiographic evaluations demonstrated an early increase in left ventricular mass and fractional shortening in both hypertensive and normotensive heart transplant recipients. Fractional shortening further diminished significantly in normotensive patients but remained elevated in hypertensive patients, demonstrating sustained enhanced contractility in this group. Further studies will help to determine the exact relation between cyclosporine dosages and hypertension and their respective roles in the development of renal insufficiency and left ventricular hypertrophy after cardiac transplantation.

[Pleuro-pulmonary paragonimiasis]. / La paragonimose pleuropulmonaire.

Paragonimiasis is a food borne zoonosis due to a trematode belonging to the genus Paragonimus. Although present throughout the world, about 90% of the cases occur in Asia where around 20 million people are infected. The parasitic cycle is complex with two different intermediate hosts. Man is infected by ingesting the raw or undercooked flesh of the second host - a freshwater crab or prawn - or possibly of a paratenic mammal host (wild boar), which contains the infective larval stage metacercariae that reaches the lung which is the main target organ. Epidemiological, pathological, and clinical aspects are reviewed. The main symptoms are protracted cough, and recurrent "benign" hemoptysis. Abnormal pleuro-pulmonary imaging features are constant, but protean and non-specific, leading to frequent confusion with tuberculosis. Diagnosis is easily achieved by ova search in the sputum or pleural fluid, or by serology. Evolution is usually considered benign, although not well known. Finally, praziquantel is the effective first choice treatment. Some paradoxical aspects of this disease are underlined such as: underdiagnosis despite a very simple diagnostic procedure, or opposite tendencies according to location, either extinction or re-emergence.

Epoch-based Entropy for Early Screening of Alzheimer's Disease.

In this paper, we introduce a novel entropy measure, termed epoch-based entropy. This measure quantifies disorder of EEG signals both at the time level and spatial level, using local density estimation by a Hidden Markov Model on inter-channel stationary epochs. The investigation is led on a multi-centric EEG database recorded from patients at an early stage of Alzheimer's disease (AD) and age-matched healthy subjects. We investigate the classification performances of this method, its robustness to noise, and its sensitivity to sampling frequency and to variations of hyperparameters. The measure is compared to two alternative complexity measures, Shannon's entropy and correlation dimension. The classification accuracies for the discrimination of AD patients from healthy subjects were estimated using a linear classifier designed on a development dataset, and subsequently tested on an independent test set. Epoch-based entropy reached a classification accuracy of 83% on the test dataset (specificity = 83.3%, sensitivity = 82.3%), outperforming the two other complexity measures. Furthermore, it was shown to be more stable to hyperparameter variations, and less sensitive to noise and sampling frequency disturbances than the other two complexity measures.

Flagellar genes from Rhodobacter sphaeroides are homologous to genes of the fliF operon of Salmonella typhimurium and to the type-III secretion system.

A flagellar region of the genome of Rhodobacter sphaeroides was cloned and sequenced. Three ORFs were identified and arranged in the same order as fliH, fliI and fliJ of Salmonella typhimurium (St). ORF2 is highly similar to FliI from St (49% similarity) showing Walker's A and B motifs. Similar scores were found with proteins of the type-III secretion system of virulence factors. ORF3 shows 16.4 and 11.1% similarity to FliJ from St and Bacillus subtilis, respectively. This work also shows that ORF3 is similar to HrpJ5 from Pseudomonas syringae (19.2% similarity). It was found that ORF2 and ORF3 start immediately downstream from the adjacent coding region, suggesting a single transcriptional unit.

Serum lipid abnormalities in heart transplant recipients: predominance of HDL2-like particles in the HDL pattern.

Accelerated coronary atherosclerosis is a major risk limiting long-term survival after heart transplantation and is commonly associated with dyslipoproteinemia even in subjects who were not dyslipoproteinemic before intervention. The purpose of this study was to analyse the abnormalities in the lipid profiles of 2 different groups of heart-transplanted males: 18 subjects with underlying ischemic heart disease (IHD) and 19 subjects with non-obstructive cardiomyopathy of unknown aetiology (CM). Both groups were compared to 33 healthy males. All patients were under immunosuppressive therapy including prednisone, cyclosporin A and azathioprine. A moderate hyperlipidemia was found in all transplant recipients, associated with high HDL-cholesterol concentrations in the CM group (1.80 +/- 0.37 vs. 1.29 +/- 0.23 mmol/l) and normal HDL-cholesterol levels in the IHD group (1.40 +/- 0.23 mmol/l). HDL subfractionation showed a marked increase in HDL2-cholesterol (CM: 1.12 +/- 0.32; IHD: 0.69 +/- 0.28; control: 0.40 +/- 0.17 mmol/l) while HDL3-cholesterol was significantly lower than in the control group. Analysis of HDL particle sizes showed in all transplant subjects an increase of an intermediate size particle HDL2a (diameter 9.0 +/- 0.10 nm) which is a minor form in control subjects. In the CM group, both the common HDL2b (10.2 +/- 0.13 nm) and HDL2a were abundant in 13 of 17 patients. The pattern was more heterogeneous in the IHD group but witnessed to a high frequency of HDL2a particles either alone (5/14) or associated with larger HDL2b (4/14) or with small HDL3 (4/14).(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction between roxithromycin and cyclosporin in heart transplant patients.

Cyclosporin is an immunosuppressive agent commonly used in transplant patients. It is actively metabolised by the cytochrome P450 system and interactions with drugs metabolised by the same system are predictable. This is particularly relevant since cyclosporin has a low therapeutic index and its renal toxicity is concentration-related. Roxithromycin, a new, well-tolerated macrolide with a weak interactive profile, uses the same isoenzyme of the P450 system as cyclosporin. To evaluate its interaction potential in clinical practice, 8 heart transplant recipients treated with cyclosporin for at least 1 month received roxithromycin for 11 days (150 mg twice daily). Bi-weekly controls of plasma cyclosporin concentrations and creatinine levels were carried out before, during and after roxithromycin treatment. A slight nonsignificant rise in cyclosporin concentrations was observed, but creatinine levels remained stable during roxithromycin treatment. Values of cyclosporin concentrations diminished after withdrawal of roxithromycin. Cyclosporin dosage adjustment was not necessary. There was a minor pharmacokinetic interaction, which can be considered safe for the usual therapeutic dosage of roxithromycin used.

Modified technique for correction of tricuspid atresia.

This study presents a new technique for correction of tricuspid atresia. All 13 patients operated upon had the same form of the anomaly, with the great arteries normally related. The principle is to conserve the pulmonary valve and anulus of the patient in its anatomic position and to exclude the hypoplastic right ventricle. Because there is no need for closing the ventricular septal defect, the risk of heart block and residual left-to-right shunts is avoided. Deaths are related to questionable indications for two patients and to a bilateral pneumothorax for the third one. The long-term follow-up (5 years for the first patient) shows good results for the 10 survivors. Six of them are in Class 1 of the New York Heart Association and four are in Class II.

Aortic dissection. Prevalence, cause, and results of late reoperations.

From January 1977 to September 1992, 143 patients underwent an emergency operation for type A acute aortic dissection. Because of the location of the intimal tear, the replacement of the ascending aorta was extended to the transverse arch in 42 patients (29.3%). One hundred ten patients (78%) survived the operation. During the same period, 32 patients had to be reoperated on once (n = 24) twice (n = 6), or three times (n = 2) for a total of 42 reoperations. Nineteen patients had had the initial repair in our institution, and 13 had been operated on elsewhere. Reoperation was indicated for aortic valve disease (n = 4), recurring dissection (n = 7) threatening aneurysmal evolution of a persisting dissection (n = 28), or false aneurysm (n = 3). The redo procedure involved the aortic root and/or ascending aorta in 15 cases (group I), the transverse arch alone in 7 cases (group II), the transverse arch and the descending aorta or the descending aorta alone in 10 cases (group III), or the thoracoabdominal aorta in 10 cases (group IV). The risk factors for reoperation have been analyzed in the 110 survivors initially operated on in our institution. Seven of 18 patients with Marfan's syndrome (38.8%) versus 12 of 92 without Marfan's syndrome (13%) were reoperated on (p = 0.023). None of the 30 patients surviving arch replacement at initial repair required a reoperation, versus 19 of 80 (23.7%) patients surviving a replacement limited to the ascending aorta (p = 0.013). The overall mortality rate of reoperation was 21.8% (7/32) with a risk of 16.6% (7/42) at each procedure (group I, 13.3%; group II, 0%; group III, 20%; group IV, 30%). Hospital mortality was influenced by emergency operation (5/10) (p < 0.005) and thoracoabdominal replacement (3/10) (p < 0.035). The late survivals after reoperation are 65.1% +/- 17.6% at 1 year and 55% +/- 19.63% at 5 years (Kaplan-Meier, confidence interval 95%). The late survivals, after the initial repair, of the patients undergoing reoperation are 89.6% +/- 11.0%, 79.3% +/- 14.7%, 53.9% +/- 18.1%, and 35.9% +/- 21.8% at 1, 5, 10, and 12 years, respectively. In conclusion, aortic dissection is an evolving process that may require one or several reoperations after the initial repair. At initial emergency operation, the resection of the entry site, when located on or extending to the transverse arch, has reduced the risk of reoperation, in our experience. Elective reoperation must be considered before the occurrence of complications, especially in patients with Marfan's syndrome.(ABSTRACT TRUNCATED AT 400 WORDS)

Valve extension with glutaraldehyde-preserved autologous pericardium. Results in mitral valve repair.

Preliminary experimental studies in our laboratory have shown that autologous pericardium treated with glutaraldehyde prevents late deterioration and calcification of the tissue. For this reason, glutaraldehyde-treated autologous pericardium has been used in a series of 64 patients who underwent operations for leaflet extension of the mitral valve between 1980 and 1989. Ages ranged from 2.5 to 60 years (mean 19 +/- 15). The causes of mitral valve insufficiency were rheumatic fever (69%), bacterial endocarditis (17%), congenital (8%), endomyocardial fibrosis (4.5%), and trauma (1.5%). The autologous tissue was fixed in a 0.62% glutaraldehyde solution for 15 minutes and rinsed in saline for an additional 15 minutes. Patching techniques varied depending on the site and the extent of the lesion. Associated mitral valve repair techniques (Carpentier's techniques) were mandatory in all patients. The period of follow-up extended from 6 months to 9 years (mean 3.1 +/- 2.5 years). There were no operative deaths in this series, and there was one late death (2%). In the six patients (12%) who underwent reoperation, there has been no case of calcification of the pericardial patch. Postoperative mitral valve function was assessed by bidimensional color Doppler echocardiographic techniques. Mitral valve insufficiency was trivial or absent in 80% of the patients. This experience permits us to conclude that leaflet extension is a simple and safe technique in valve reconstruction, allowing repair of mitral valves that otherwise would need to be replaced. It permits use of an adult-size prosthetic ring in children. Glutaraldehyde-treated autologous pericardium is the material of choice for this type of repair.

Cold cerebroplegia. A new technique of cerebral protection during operations on the transverse aortic arch.

Profound hypothermia associated with circulatory arrest is the commonest method of cerebral protection during operations on the aortic arch. This technique allows a limited time to perform the aortic repair, however. It also necessitates prolonged cardiopulmonary bypass to rewarm the patient. This may be the cause of coagulation disorders or infection. Selective perfusion of the carotid arteries can also be used. When the perfusion is derived from the main arterial line, however, the repair of the aorta requires that the vessel be crossclamped, and cannot be performed in an "open, bloodless" manner. To avoid the disadvantages of both techniques, we have developed a new technique of cerebral protection. After a regular cardiopulmonary bypass has been established, the carotid arteries are cannulated and perfused with blood cooled at 6 degrees to 12 degrees C, through a separate heat exchanger, while the core temperature is maintained at moderate hypothermia (25 degrees to 28 degrees C, rectal). To perform the "open" distal repair, the cardiopulmonary bypass is discontinued while the carotid perfusion is maintained (250 to 350 ml/min). When the distal repair is completed, cardiopulmonary bypass is resumed and the carotid perfusion is discontinued. Between 1984 and June 1989, 54 patients (mean age 55 years) were operated on with this method (45 elective operations, 9 emergency procedures). Mean duration of cardiopulmonary bypass was 121 minutes (65 to 248), and mean duration of circulatory arrest was 22 minutes (10 to 51). The electroencephalogram, routinely recorded, showed return of the cerebral activity after a mean time of 12 minutes and normal activity after a mean time of 66 minutes. There was no intraoperative death. Hospital mortality rate was 13% (7/54). One death was related to neurologic disorders. All patients but one awakened normally within 8 hours after operation. Two patients (4.3%) experienced a transient neurologic episode (lateral hemianopia) 9 and 11 days postoperatively. There was no hemorrhagic complication (24-hour average blood loss: 840 +/- 540 ml). In our experience the technique of "cold cerebroplegia" has been demonstrated to provide excellent cerebral protection. It requires no prolonged cardiopulmonary bypass and does not limit the time necessary to perform the aortic repair. It may be considered as a safe alternative to profound hypothermia associated with circulatory arrest.

Valve repair with Carpentier techniques. The second decade.

Among 206 consecutive patients having undergone mitral valve repair with a prosthetic ring between 1972 and 1979 in our institution, the 195 patients (94.5%) who survived the operation were studied to assess the long-term function of this method of repair. Patients' ages ranged from 18 to 79 years (mean age 48.7 years). Mitral valve insufficiency was due to degenerative disease in 113 patients (58%), rheumatic disease in 74 (38%), ischemia and other causes in eight patients (4%). A total of 188 patients (9.7%) were in New York Heart Association class III or IV preoperatively and 94 (48%) had atrial fibrillation. The patients were divided into three functional groups: type I (normal leaflet motion), 35 patients (18%); type II (leaflet prolapse), 147 patients (75%); and type III (restricted leaflet motion), 13 patients (7%). The techniques included prosthetic ring annuloplasty (185 patients), leaflet resection (158 patients), chordal shortening (89 patients), leaflet mobilization (10 patients) and papillary muscle reimplantation (2 patients). Long-term follow-up was available in 189 patients (96.8%), for a rate of 2316 patients per year. The 15-year actuarial and valve-related survival rates were 72.4% and 82.8%, respectively. At 15 years, 93.9% of the patients were free from thromboembolism, 96.6% free from endocarditis, 95.6% free from anticoagulant-related hemorrhage, and 87.38% free from reoperation. Actuarial rate of freedom from reoperation was higher in the group with degenerative disease (92.7%) than in the group with rheumatic disease (76.12%). Among the 157 survivors, 117 (74%) were in New York Heart Association class I and class II and 105 (66%) were in sinus rhythm. Doppler echocardiographic studies showed normal ventricular contractility in 134 patients (84.5%), absence of mitral regurgitation in 112 (74%), trivial regurgitation in 27 (17%), and significant regurgitation in 4 patients (2.5%).

Surgical treatment of asymptomatic and mildly symptomatic mitral regurgitation.

OBJECTIVE: The purpose of this study was to review the risk-benefit ratio of mitral valve repair in patients with severe mitral regurgitation and no or mild symptoms. METHODS: From January 1989 to December 1994, 584 patients were operated on for mitral regurgitation. Of these, 175 patients were in New York Heart Association class I or II with grade 3 to 4 isolated chronic mitral regurgitation. They comprise our study population. Mean age was 51.3 +/- 14.3 years. Principal causes of mitral regurgitation were degenerative in 128 (73%) and rheumatic in 26 patients (15%). Leaflet prolapse was the mechanism responsible for regurgitation in 152 patients (86%). Mitral valve repair was performed in 174 patients, and one patient required initial valve replacement. Mean follow-up was 34.3 +/- 18.8 months. RESULTS: Three patients died, for an overall mortality of 1.7%. Five patients were reoperated on, for an actuarial freedom from reoperation of 97.0% +/- 0.8% at 5 years. Actuarial freedom from thromboembolism and endocarditis was 96.3% +/- 1.7% and 99.4% +/- 0.6%, respectively, for an event-free survival of 91.0% +/- 2.0% at 5 years. Left atrial diameter decreased from 54.3 +/- 11.6 mm to 43.6 +/- 10.5 mm (p < 0.001). Left ventricular end-systolic and end-diastolic diameters decreased from 40.0 +/- 6.8 mm and 64.8 +/- 7.0 mm to 34.6 +/- 6.7 mm (p < 0.001) and 52.7 +/- 7.4 mm (p < 0.001), respectively. Mean residual mitral regurgitation was 0.44 +/- 0.6. CONCLUSION: Mitral valve repair for chronic mitral regurgitation in patients having mild or no symptoms was performed with low mortality and morbidity, good valve function, and preserved late left ventricular performance. Early repair may be advocated on the basis of severity of regurgitation and valve repairability, regardless of symptoms.