Research on the volatility, phase transitions and thermodynamic stability of five organochlorine compounds.

The present investigation describes the experimental evaluation of relevant physicochemical properties of five organochlorine compounds (OCs), including some that are related to their environmental mobility. The vapor pressures of (2,4'-Dichlorodiphenyl)dichloroethane (2,4'-DDD, CASN:53-19-0), 1,1-Dichloro-2,2-bis(4-chlorophenyl)ethane (4,4'-DDD, CASN:72-54-8) and 2,2-Bis(4-chlorophenyl)acetic acid (4,4'-DDA, CASN:83-05-6), as well as of the bactericide Nitrapyrin (CASN:1929-82-4) and of the rodenticide Crimidine (CASN:535-89-7) were determined at different temperatures. The Knudsen mass-loss effusion technique was employed to determine the sublimation vapor pressures of the referred compounds, apart from Crimidine. For the latter compound, a static method using a capacitance diaphragm manometer enabled the measurement of vapor pressures of both condensed (crystalline and liquid) phases. This technique was also used to measure the vapor pressures of the crystalline phase of Nitrapyrin over a larger temperature range, as well as its vaporization vapor pressures. The results of the standard molar enthalpies, entropies, and Gibbs energies of sublimation for all five compounds and of vaporization for Crimidine and Nitrapyrin, at reference temperatures, were derived. For these two compounds the phase diagram representations of the (p,T) results, in the vicinity of the triple point, were obtained. DSC analysis enabled the determination of the crystalline heat capacities of the five OCs studied and also of their temperatures and enthalpies of fusion. Gas-phase thermodynamic properties were estimated using quantum chemical calculations. The thermodynamic stability of the compounds studied was evaluated and compared in the crystalline and gaseous phases, at 298.15 K, in consideration with estimated results of the standard Gibbs energies of formation. Combined with other physical and chemical properties, the results derived from this study can be used to predict the mobility, and environmental fate of these pollutants.

Phase Transitions Equilibria of Five Dichlorinated Substituted Benzenes.

This work reports an experimental study aiming to determine the thermodynamic properties of five chlorinated compounds with environmental impact. The vapor pressures of the crystalline phases of three isomers of dichlorobenzoic acid (2,4-, 2,5-, and 2,6-) and 2,6-dichlorobenzonitrile were measured at several temperatures using the Knudsen effusion technique. Another technique (a static method based on capacitance diaphragm manometers) allowed the measurement of the vapor pressures of both the crystalline and liquid phases of 2,4-dichlorobenzonitrile between 303.0 and 380.0 K. This latter technique also enabled the measurement of sublimation vapor pressures of 2,6-dichlorobenzonitrile over a larger range interval of temperatures, T = 328.7 and 391.8 K. The standard molar enthalpy, entropy, and Gibbs energy of sublimation (for all the compounds studied) and vaporization (for 2,4-dichlorobenzonitrile) were derived, at reference temperatures, from the experimental vapor pressure results. The temperatures and enthalpies of fusion and the isobaric heat capacities of the five crystalline-substituted benzenes were determined using differential scanning calorimetry. The contributions of the three substituents (-COOH, -CN, and -Cl) to the sublimation thermodynamic properties of the compounds studied were discussed.

Cortisol AuPd plasmonic unclad POF biosensor.

This paper presents the development and feasibility tests of a cortisol immunosensor. The sensor is based on surface plasmon resonance (SPR) using an unclad plastic optical fiber (POF) in which the SPR is used as sensitivity enhancer, promoted by a gold/palladium (AuPd) alloy coating. The AuPd coated fibers were functionalized with an anti-cortisol antibody and passivated with bovine serum albumin (BSA) to be tested in the presence of cortisol as target analyte. The antibody-antigen binding reaction caused a variation of the refractive index on the surface of the AuPd coating, which leads to a shift of the SPR signature wavelength. The sensor was tested for different cortisol concentrations, ranging from 0.005 to 10 ng/mL. The reported biosensor presented a total wavelength shift of 15 nm for the testing range, putting in evidence a high sensitivity. Control tests for selectivity assessment were also performed. Concentrations as high as 10 ng/mL of cortisol, in a sensor functionalized with anti-hCG antibodies, only resulted in 1 nm variation of the resonance wavelength, 15 times lower than the one functionalized with the anti-cortisol antibodies, which indicates a high selectivity for the proposed approach. For this sensing approach the limit of detection (LOD) was determined to be 1 pg/mL. The proposed SPR based POF sensor has a low-cost interrogation method, high sensitivity and low LOD, straightforward signal processing and find important applications in different biological fields.

Thermodynamic Stability of Fenclorim and Clopyralid.

The present work reports an experimental thermodynamic study of two nitrogen heterocyclic organic compounds, fenclorim and clopyralid, that have been used as herbicides. The sublimation vapor pressures of fenclorim (4,6-dichloro-2-phenylpyrimidine) and of clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) were measured, at different temperatures, using a Knudsen mass-loss effusion technique. The vapor pressures of both crystalline and liquid (including supercooled liquid) phases of fenclorim were also determined using a static method based on capacitance diaphragm manometers. The experimental results enabled accurate determination of the standard molar enthalpies, entropies and Gibbs energies of sublimation for both compounds and of vaporization for fenclorim, allowing a phase diagram representation of the (p,T) results, in the neighborhood of the triple point of this compound. The temperatures and molar enthalpies of fusion of the two compounds studied were determined using differential scanning calorimetry. The standard isobaric molar heat capacities of the two crystalline compounds were determined at 298.15 K, using drop calorimetry. The gas phase thermodynamic properties of the two compounds were estimated through ab initio calculations, at the G3(MP2)//B3LYP level, and their thermodynamic stability was evaluated in the gaseous and crystalline phases, considering the calculated values of the standard Gibbs energies of formation, at 298.15 K. All these data, together with other physical and chemical properties, will be useful to predict the mobility and environmental distribution of these two compounds.

Black Wattle (Acacia mearnsii) Condensed Tannins as Feed Additives to Lactating Dairy Cows.

The objective of this study was to evaluate the effects of five levels of condensed tannins (CT) from black wattle (Acacia mearnsii) in the diets of lactating dairy cows on intake, nutrient digestibility, ruminal microbial protein synthesis, milk production, composition, oxidative profile, and blood metabolites. Five Holstein cows (88 ± 26.8 days in milk) were allocated in a 5 x 5 Latin square design for a period of 20 days (14 days of diet adaptation and six for sampling). Treatments were the inclusion levels of CT at 0, 5, 10, 15 and 20 g/kg of dry matter (DM) in the diet. There was no effect of CT on DM intake. The digestibility of DM and neutral detergent fiber changed quadratically, with the maximum values at 12.2 and 11.4 g/kg of DM, respectively. There was no effect on ruminal microbial protein synthesis and milk production; however, milk casein concentration was reduced linearly. There was no effect on the milk oxidative profile. Inclusion of CT at levels up to 20 g/kg of DM did not affect intake or microbial protein synthesis; however, added CT depressed the production of energy corrected milk and milk casein concentration.

Osteoclasts degrade fibrinogen scaffolds and induce mesenchymal stem/stromal osteogenic differentiation.

Fibrinogen (Fg) is a pro-inflammatory protein with pro-healing properties. Previous work showed that fibrinogen 3D scaffolds (Fg-3D) promote bone regeneration, but the cellular players were not identified. Osteoclasts are bone resorbing cells that promote bone remodeling in close crosstalk with osteoblasts. Herein, the capacity of osteoclasts differentiated on Fg-3D to degrade the scaffolds and promote osteoblast differentiation was evaluated in vitro. Fg-3D scaffolds were prepared by freeze-drying and osteoclasts were differentiated from primary human peripheral blood monocytes. Results obtained showed osteoclasts expressing the enzymes cathepsin K and tartrate resistant acid phosphatase colonizing Fg-3D scaffolds. Osteoclasts were able to significantly degrade Fg-3D, reducing the scaffold's area, and increasing D-dimer concentration, a Fg degradation product, in their culture media. Osteoclast conditioned media from the first week of differentiation promoted significantly stronger human primary mesenchymal stem/stromal cell (MSC) osteogenic differentiation, evaluated by alkaline phosphatase activity. Moreover, week 1 osteoclast conditioned media promoted earlier MSC osteogenic differentiation, than chemical osteogenesis inductors. TGF-ß1 was found increased in osteoclast conditioned media from week 1, when compared to week 3 of differentiation. Taken together, our results suggest that osteoclasts are able to differentiate and degrade Fg-3D, producing factors like TGF-ß1 that promote MSC osteogenic differentiation.

Estimations of the thermodynamic properties of halogenated benzenes as they relate to their environment mobility.

In this work, several simple new equations for predicting important environmental mobility properties, at T = 298.15 K, were derived for halogenated benzenes: standard Gibbs energy of hydration, aqueous solubility, octanol-water partition coefficients, and Henry's law constants. A discussion on our previous estimates of other related properties (standard Gibbs energy and vapor pressure of sublimation and of vaporization) and their relation with entropy of fusion is also presented. As we aimed to estimate these properties for any of the ca. 1500 halogenated benzenes that may exist theoretically, an equation for estimating the temperature of fusion was also derived, since some of the proposed predictive equations (solubility of solids and Gibbs energy of sublimation) require its knowledge. For the other estimated properties just the number of each halogen that replaces hydrogen atoms in the halogenated benzene is needed. It was found that the coefficients that multiply the number of halogen atoms in the predictive equations vary linearly with the volume of the halogen atom.

Fibrinogen scaffolds with immunomodulatory properties promote in vivo bone regeneration.

The hypothesis behind this work is that fibrinogen (Fg), classically considered a pro-inflammatory protein, can promote bone repair/regeneration. Injury and biomaterial implantation naturally lead to an inflammatory response, which should be under control, but not necessarily minimized. Herein, porous scaffolds entirely constituted of Fg (Fg-3D) were implanted in a femoral rat bone defect and investigated at two important time points, addressing the bone regenerative process and the local and systemic immune responses, both crucial to elucidate the mechanisms of tissue remodelling. Fg-3D led to early infiltration of granulation tissue (6 days post-implantation), followed by bone defect closure, including periosteum repair (8 weeks post-injury). In the acute inflammatory phase (6 days) local gene expression analysis revealed significant increases of pro-inflammatory cytokines IL-6 and IL-8, when compared with non-operated animals. This correlated with modified proportions of systemic immune cell populations, namely increased T cells and decreased B, NK and NKT lymphocytes and myeloid cell, including the Mac-1+ (CD18+/CD11b+) subpopulation. At 8 weeks, Fg-3D led to decreased plasma levels of IL-1ß and increased TGF-ß1. Thus, our data supports the hypothesis, establishing a link between bone repair induced by Fg-3D and the immune response. In this sense, Fg-3D scaffolds may be considered immunomodulatory biomaterials.

Controlled pericardiocentesis in patients with cardiac tamponade complicating aortic dissection: experience of a centre without cardiothoracic surgery.

BACKGROUND: Cardiac tamponade has been reported in 18.7% of patients with acute type A aortic dissection and its presence is associated with worse outcomes. Emergency aortic repair together with intra-operative pericardial drainage is the recommended treatment approach. However, controversy surrounds how to manage patients with haemopericardium and cardiac tamponade who cannot survive until surgery. PURPOSE: To describe a case series of patients with critical cardiac tamponade complicating aortic dissection admitted to a hospital without cardiothoracic surgery, and in whom preoperative controlled pericardial drainage was performed. METHODS AND RESULTS: Single centre retrospective study: during a nine-year period, 21 patients with Stanford type A aortic dissection were admitted at our centre; six of them (28.6%) presented clinical and echocardiographic signs of cardiac tamponade (four males; mean age 58±17 years). In this subgroup, controlled pericardiocentesis was safely performed with no major immediate complications and it was effective in five patients, improving haemodynamic instability and allowing transfer to the operating room. CONCLUSIONS: Preoperative controlled pericardiocentesis can be lifesaving when managing patients with critical cardiac tamponade (pulseless electrical activity or refractory hypotension) complicating acute type A aortic dissection, namely when cardiac surgery is not immediately available.

Clinical applications of exercise stress echocardiography in the treadmill with upright evaluation during and after exercise.

Exercise stress echocardiography is the most frequently used stress test in our laboratory. Exercise echocardiography is used mainly in the study of patients with coronary artery disease. However, the technique is increasingly being used to study other diseases. In our centre, we use an original methodology, published by us in 2000, in which we evaluate heart function during exercise in the treadmill. After the exercise, patients are maintained in orthostatic position when appropriate or lying down in left lateral decubitus for further evaluation. Since this method seems to increase the quality and the quantity of information obtained in so many clinical arenas, we now present a detailed review of this methodology and its applications.

Synthesis and characterization of a lipidic alpha amino acid: solubility and interaction with serum albumin and lipid bilayers.

The lipidic α-amino acid with 11 carbons in the alkyl lateral chain (α-aminotridecanoic acid) was synthesized via multicomponent hydroformylation/Strecker reaction, which is a greener synthetic approach to promote this transformation relative to previously described methods. Its solubility and aggregation behavior in aqueous solutions was characterized, as well as the interaction with lipid bilayers. Lipidic amino acids are very promising molecules in the development of prodrugs with increased bioavailability due to the presence of the two polar functional groups and nonpolar alkyl chain. They are also biocompatible surfactants that may be used in the food and pharmaceutical industry. In this work we have conjugated the lipidic amino acid with a fluorescent polar group (7-nitrobenz-2-oxa-1,3-diazol-4-yl), to mimic drug conjugates, and its association with serum proteins and lipid bilayers was characterized. The results obtained indicate that conjugates of polar molecules with lipidic α-amino acid, via covalent attachment to the amine group, have a relatively high solubility in aqueous solutions due to their negative global charge. They bind to serum albumin with intermediate affinity and show a very high partition coefficient into lipid bilayers in the liquid-disordered state. The attachment of the polar group to the lipidic amino acid increased strongly the aqueous solubility of the amphiphile, although the partition coefficient into lipid membranes was not significantly reduced. Conjugation of polar drugs with lipidic amino acids is therefore an efficient approach to increase their affinity for biomembranes.

Effusive-constrictive pericarditis: the role of noninvasive imaging.

Effusive-constrictive pericarditis is a rare entity in which clinical suspicion is of paramount importance, and although cardiac catheterization remains the gold standard for diagnosis, noninvasive imaging techniques are very useful in consolidating the diagnosis prior to confirmation by invasive means. The authors describe the case of a 52-year-old man, who had undergone heart surgery in the past, with a long history of heart failure refractory to medical therapy and chronic recurrent pericardial effusion, in whom noninvasive imaging techniques were decisive in arriving at the correct diagnosis of effusive-constrictive pericarditis, which was later confirmed by cardiac catheterization, thus enabling the correct therapeutic approach to be adopted and leading to improvement in clinical status.

[Value of exercise echocardiography in aortic recoarctation--case report]. / Utilidade da ecocardiografia de esforço na recoarctação da aorta--caso clínico.

In this article the authors present a case study of a young man with coarctation of the aorta that underwent surgical correction at 4 months old, for whom the exercise echocardiogram was important in determining the functional importance of recoarctation and the decision of the timing for re-intervention, demonstrating the importance of this technique to discriminate the functional significance of this pathology.

Stress-induced intraventricular gradients in symptomatic athletes during upright exercise continuous wave Doppler echocardiography.

The development of significant intraventricular gradients (IVGs) during exercise has been described anecdotally in athletes. However, the prevalence and clinical effect of this observation are unclear. In addition, the most appropriate exercise technique (upright vs semisupine) for eliciting IVGs also remains unknown. The present study had 2 main aims: (1) to identify the prevalence of exercise IVGs in athletes whose preparticipation cardiovascular screening result for sports practice, according to the European Society of Cardiology guidelines, was positive; and (2) to evaluate the influence of performing exercise echocardiography, as described, on the detection of IVGs. We enrolled 139 consecutive athletes (135 amateurs and 4 professionals, mean age 22 ± 9.9 years; 30 women) who underwent treadmill exercise echocardiography. In each athlete, the IVG was evaluated by continuous wave Doppler during 5 conditions: left lateral decubitus at rest; upright at rest; upright at peak treadmill exercise; upright in the recovery phase; and left lateral decubitus in the recovery phase. All patients had normokinetic regional wall motion at rest and during exercise. According to the detection of IVG during treadmill echocardiography (IVG was considered significant if >30 mm Hg at rest or >50 mm Hg during/after exercise), 2 groups were identified: a group (n = 52), with significant IVG and a group (n = 87) without significant IVG. The IVG was greater in the upright position, both at rest (only 2 athletes from group with IVG) and after exercise (52 athletes, all from group with IVG). The IVG was lower in the recovery phase in the left lateral decubitus position (55 ± 15 mm Hg in 30 athletes, all from group with IVG) than in the upright position in the recovery phase (95 ± 35 mm Hg in 52 athletes, all from group with IVG) and at peak exercise (66 ± 24 mm Hg in 41 athletes from group with IVG). We observed systolic anterior movement of the mitral valve in 33 of the 52 athletes in the group with IVG and in none of the athletes in the group without IVG. In conclusion, in athletes, exercise-induced symptoms and/or ischemia-like electrocardiographic signs are often associated with significant IVG, developing in the absence of wall motion abnormalities. IVG was more evident during post-treadmill upright imaging.

The importance of cardiac magnetic resonance imaging in the diagnosis of myocarditis--a case report.

The authors describe the case of a 16-year-old male, who went to the emergency department with a clinical setting characterized by chest pain, electrocardiographic pattern of inferoposterior acute myocardial infarction and elevated markers of myocardial necrosis. Cardiac catheterization revealed no significant coronary lesions and the transthoracic echocardiogram showed no segmental abnormalities. Myocarditis was suspected, and this diagnosis was confirmed by magnetic resonance imaging. This case demonstrates the difficulty of establishing a definitive diagnosis of myocarditis and the increasing importance of cardiac magnetic resonance imaging in this area.

Efficacy of beta-blocker therapy in symptomatic athletes with exercise-induced intra-ventricular gradients.

BACKGROUND: Upright exercise stress echocardiography (SE) induces significant intraventricular gradient (IVG) and systolic anterior motion (SAM) in a large proportion of symptomatic athletes, who may therefore benefit from a negative inotropic therapy.The purpose of the present study was to assess the effect of chronic oral ß blocker therapy on the occurrence of exercise-induced IVG and mitral valve SAM, in symptomatic athletes. METHODS: We enrolled 35 symptomatic athletes (age = 23 ± 11 years) with IVG (>30 mmHg) during SE off therapy. All repeated SE on chronic oral beta-blocker therapy (atenolol up to 50 mg, bisoprolol up to 10 mg, or metoprolol up to 100 mg daily according to physician-driven choice). RESULTS: On therapy, there was during SE a reduction in IVG (35 off vs 17 on beta blocker, p < 0.01), decrease of IVG (102 ± 34 mmHg off vs 69 ± 24 mmHg on beta blocker, p < 0.01), peak heart rate (178 ± 15 bpm off vs 157 ± 9 bpm on beta blocker), SAM (24 off vs 9 on beta blocker, p < 0.001), symptoms during SE (17 off vs 2 on beta blocker p < 0.001), ST segment depression (13 off vs 2 on beta blocker, p < 0.001). CONCLUSIONS: In athletes with positive screening on medical evaluation for sports practice and IVG on exertion, treatment with oral beta blockers improved symptoms in the large majority of patients. Symptomatic benefit was mirrored by objective evidence of improvement of echocardiographic signs of obstruction (IVG and SAM) and reduction of ischemia-like electrocardiographic changes.

A calorimetric and computational study of aminomethoxybenzoic acids.

The standard (p(0) = 0.1 MPa) molar enthalpies of formation, in the crystalline phase, of five aminomethoxybenzoic acids, at T = 298.15 K, were derived from the standard molar energies of combustion in oxygen, measured by static-bomb combustion calorimetry. Combining these results with literature results of the standard molar enthalpies of sublimation, at T = 298.15 K, the standard molar enthalpies of formation, in the gaseous phase, were derived. Additionally, the enthalpies of formation of the ten possible isomers of aminomethoxybenzoic acid were estimated using accurate Double Hybrid Density Functional Theory (DHDFT) computational methods. The good agreement between the experimental and estimated values of the enthalpies of formation of the five isomers studied experimentally allows us to be confident on the estimated values for the other five isomers. A quantitative evaluation and analysis of the aromatic character of all the studied isomers based on the calculation of Nucleus Independent Chemical Shifts (NICS) was also conducted.

Cyclohexane selective photocatalytic oxidation by anatase TiO2: influence of particle size and crystallinity.

A systematic study is presented on the effect of crystallite size of Anatase (Hombikat, Sachtleben), varied by calcination at different temperatures up to 800 degrees C, on photocatalytic activity in cyclohexane selective oxidation. Two different reactors were used to test the materials: a top illumination reactor and an in situ ATR-FTIR cell. Properties such as crystallinity and associated availability of holes and electrons for surface reactions, as well as the amount of surface OH-groups, are shown to have a significant influence on TiO(2) activity, (surface) selectivity, and stability. Upon increasing the crystallite size, productivity (g(-1)(catalyst)) decreases, while (i) the TOF (moles of cyclohexanone formed per minute per OH-site), (ii) the rate of cyclohexanone desorption, (iii) catalytic site stability, and (iv) the cyclohexanol/cyclohexanone ratio increase. The results are discussed on the basis of a reaction scheme, and a simple reaction rate equation.

The usefulness of contrast during exercise echocardiography for the assessment of systolic pulmonary pressure.

BACKGROUND: The systolic pulmonary artery pressure (PAPs) can be accurately estimated, non-invasively, using continuous-wave Doppler (CWD) ultrasound measurement of the peak velocity of a tricuspid regurgitant (TR) jet. However, it is often difficult to obtain adequate tricuspid regurgitation signals for measurement of PAPs, what could lead to its underestimation. Therefore, utilization of air-blood-saline contrast has been implemented for the improvement of Doppler signal in several clinical contexts. It is now recommended in the evaluation of patients with pulmonary hypertension. Physical activity is severely restricted in patients with PAH, being exertional dypnea the most typical symptom. Exercise stress echo-Doppler imaging allows assessment of the response to exercise. It is an excellent screening test for patients with suspected PAH. Our purpose was to evaluate the value and accuracy of agitated saline with blood contrast echocardiography, in the improvement of the Doppler signal, to quantify PAPs during treadmill exercise-echocardiography. PURPOSE: To evaluate the value of contrast echocardiography, using agitated saline with blood, in the improvement of the Doppler signal used to quantify the pulmonary artery systolic pressure during exercise. METHODS: From a total of 41 patients (pts), we studied 38 pts (93%), 35 women, aged 54 +/- 12 years-old. 27 with the diagnosis of systemic sclerosis, 10 with history of pulmonary embolism and one patient with a suspected idiopathic PAH, who were referred to the Unity of Heart Failure and Pulmonary Hypertension for screening of PAH. According to the Unity protocol, a transthoracic echocardiogram was made, in left decubitus (LD), with evaluation of right ventricle-right atria gradient (RV/RAg). A peripheral venous access was obtained, with a 3-way stopcock and the patients were placed in orthostatism (O), with a new evaluation of RV/RAg. Exercise echocardiography (EE) was begun, with evaluation of RV/RAg at peak exercise (P) and afterwards agitated saline (8 cc with 1 cc of air and 1 cc of blood) was injected, followed by a new evaluation of RV/RAg (PC) and then the interruption of the EE. Pulmonary Hypertension was diagnosed when RV/RAg at the end of the exercise was superior to 40 mmHg. RESULTS: The quality of Doppler signal was deteriorated in 5 pts, maintained in 6 pts and improved in 26 pts, with the use of contrast. In one patient, an interventricular septal defect was diagnosed. In 6 pts, a Doppler signal was only obtained with the use of contrast. In 15 pts, a RV/RAg superior to 40 mmHg was only obtained with the use of contrast. Of these, 9 have already been submitted to right heart cathetherism, that confirmed the diagnosis of pulmonary hypertension in 5 of them (56%). RV/RAg (P) was 44 +/- 11 mmHg and RV/RAg (PC) was 54 +/- 11 mmHg, p < 0,001. CONCLUSION: 1. The method is applicable in a large number of patients. 2. RV/RA gradients obtained at peak exercise are higher with the use of contrast, and the clinical meaning of this difference should be evaluated in a larger number of pts submitted to right heart cathetherism. The high number of false positives should lead to a higher diagnostic threshold. 3. This method seems to have relevant clinical value in the diagnosis of pulmonary arterial hypertension.

Echocardiography during treadmill exercise testing for evaluation of pulmonary artery systolic pressure: advantages of the method.

INTRODUCTION: Determination of pulmonary artery systolic pressure by Doppler echocardiography (based on the pressure gradient between the right ventricle and right atrium - DeltaP RV/RA) or by right heart catheterization is useful in evaluating the severity and prognosis of cardiac disease. The aim of the study was to evaluate DeltaP RV/RA non-invasively during treadmill exercise in patients with tricuspid regurgitation and without coronary artery disease. METHODS: Of a total of 149 patients referred to our echo laboratory, we completed the study in 142 (95%), of whom 120 were women, mean age 52+/-13 years (23 to 82). We studied 68 patients with valvular heart disease (of whom 56 had mitral valve stenosis and sinus rhythm on ECG), 42 with systemic sclerosis, 10 with severe pulmonary hypertension, 12 with a history of pulmonary embolism and 10 healthy controls. The DeltaP RV/RA was determined from the tricuspid regurgitation jet using continuous wave Doppler in left lateral decubitus (LLD) before exercise testing (BLLD), in a standing position (SP), at peak workload (PW) before termination of the test, and in the first 60 seconds of the recovery period in LLD (RLLD). RESULTS: The DeltaP RV/RA in BLLD was 36+/-21 mmHg (range 18 to 147); the SP [symbol: see text]P RV/RA was 32+/-24 mmHg (range 12 to 137), p<0.001 vs. BLLD DeltaP RV/RA; the PW DeltaP RV/RA was 58+/-26 mmHg (range 28 to 177), p<0.0001 vs. SP DeltaP RV/RA; and the RLLD DeltaP RV/RA was 47+/-25 mmHg (range 20 to 152), p<0.001 vs. PW DeltaP RV/RA. The differences between PW DeltaP RV/RA and RLLD DeltaP RV/RA changed therapeutic decisions in 10 patients (18%) with mitral stenosis, and modified the management of 13 patients (30%) with systemic sclerosis (who then underwent right heart catheterization). CONCLUSIONS: Echocardiography during treadmill exercise testing was feasible in most patients. The DeltaP RV/RA decreases in response to the standing position. The DeltaP RV/RA rises considerably with exercise in the majority of patients and is significantly higher at peak workload than in the recovery period. The differences between PW DeltaP RV/RA and RLLD DeltaP RV/RA influenced patient management.