Effect of environmental variables and their interaction on gordiid hairworm larvae (Nematomorpha).

The different stages of the life cycle of parasites are important components of ecosystems. Changes in environmental conditions may affect free-living stages, host-parasite interactions and ecosystem functioning. The larvae of Chordodes nobilii, which belongs to the parasitic phylum Nematomorpha, are susceptible to extreme temperatures and different pollutants, but the effects of pH and moderate temperature variations have not been evaluated yet. Our objective was to assess the effect of temperature, pH and their interaction on the infectivity of C. nobilii larvae to Aedes aegypti larvae over time. Larvae were treated with factorial combinations of temperature (18, 23 and 28°C), pH (7, 8 and 9) and time periods (24 and 48 h). Results show a highly significant interaction among all variables. The highest infectivity was recorded at 18°C and pH 7 at 24 and 48 h, and the lowest one at 28°C and pH 8 at 24 and 48 h. Infectivity differed significantly among the three temperatures only at pH 8 and 48 h, decreasing with increasing temperature. Our study is the first report of the effect of pH on a Nematomorpha species and suggests that the infectivity of C. nobilii larvae may be affected negatively by an increase in temperature and its interaction with pH and time. Since parasites must be considered for a better understanding of the effects of stressors on freshwater ecosystems, our results may help in the design and analysis of studies of anthropogenic impact.

Metastatic liposarcoma of the heart. Case series and brief literature review.

Secondary cardiac tumors are 20-40 times more frequent than primary lesions. Primary cardiac lesions are represented by myxomas when related to benign tumors, and by sarcomas in terms of malignant disease. Metastases to the heart from liposarcomas are very rare. We present three cases of secondary liposarcomas involving the left atrium, the right atrium, and the pericardium.

Prognostic value of dipyridamole echocardiography early after myocardial infarction in elderly patients. Echo Persantine Italian Cooperative (EPIC) Study Group.

OBJECTIVES: This study was conducted to assess the feasibility, safety and prognostic value of dipyridamole echocardiography in elderly patients recovering from an uncomplicated acute myocardial infarction in a subset analysis performed on the patients entered in the subproject "residual ischemia" of the Echo Persantine Italian Cooperative Study (EPIC). BACKGROUND: Coronary heart disease accounts for two thirds of all deaths in the age group > 65 years, and > 50% of all patients admitted to the hospital with acute myocardial infarction are > 65 years old. The prognostic value of dipyridamole-induced left ventricular dysfunction was clearly established in patients evaluated early after acute infarction. METHODS: In a subgroup analysis of the Echo Persantine Italian Cooperative Study (EPIC), we assessed the value of dipyridamole echocardiography in predicting cardiac events in 190 elderly (> or = 65 years) patients (age 68.4 +/- 3.3 years, range 65 to 78; 147 men and 43 women) evaluated early (mean 10 days) after uncomplicated acute myocardial infarction and followed up for 14 +/- 9.8 months. RESULTS: There was no major side effect during dipyridamole echocardiography. A positive test result occurred in 85 patients (44.7%). During follow-up, there were 62 events (14 cardiac deaths, 7 nonfatal reinfarctions, 21 cases of class III or IV angina and 20 revascularization procedures). Of these 62 events, 44 occurred among 85 patients with positive dipyridamole echocardiography and 18 among 105 patients with negative dipyridamole echocardiography (52% vs. 17%, p < 0.001). Spontaneous events (death, reinfarction, angina) occurred in 31 patients with positive and in 11 with negative dipyridamole echocardiography (36% vs. 10%, p < 0.001). Hard events (myocardial infarction or death) occurred in 14 patients with positive and 7 with negative dipyridamole echocardiography (16% vs. 6%, p < 0.05). Death occurred in 11 patients with positive and in 3 with negative dipyridamole echocardiography (13% vs. 3%, p < 0.01). The positive predictive value of positive dipyridamole echocardiography and negative predictive value of negative dipyridamole echocardiography as related to the occurrence of all events in the follow-up period (death, reinfarction, angina, revascularization procedures) were 52% and 83%, respectively. The relative risk (that is, the relative risk of occurrence of future cardiac events in the group with positive dipyridamole echocardiography compared with that in those with negative dipyridamole echocardiography) was 3 for all events and 4.4 for death. CONCLUSIONS: Dipyridamole echocardiography was well tolerated by elderly patients and proved to be very effective in prognostic stratification early after uncomplicated acute myocardial infarction, even when only survival was considered.

Stress echocardiographic results predict risk of reinfarction early after uncomplicated acute myocardial infarction: large-scale multicenter study. Echo Persantine International Cooperative (EPIC) Study Group.

OBJECTIVES: This study sought to assess the value of dipyridamole echocardiography in predicting reinfarction in patients evaluated early after uncomplicated acute myocardial infarction. BACKGROUND: The identification of future nonfatal reinfarction seems an elusive target for physiologic testing. However, a large sample population is needed to detect minor differences in phenomena with a low event rate. METHODS: We assessed the value of dipyridamole echocardiography in predicting reinfarction in 1,080 patients (mean [+/- SD] age 56 +/- 9 years; 926 men, 154 women) evaluated early (10 +/- 5 days) after uncomplicated acute myocardial infarction and followed up for 14 +/- 10 months. RESULTS: Submaximal studies due to limiting side effects occurred in 14 patients (1.3%); these test results were included in the analysis. Results of dipyridamole echocardiography were positive in 475 patients (44%). During follow-up, there were 50 reinfarctions: 45 nonfatal, 5 fatal (followed by cardiac death < or = 4 days after reinfarction). Reinfarction (either nonfatal or fatal) occurred in 30 patients with positive and 20 with negative results (6.3% vs. 3.3%, p < 0.01). Nonfatal reinfarction occurred in 25 patients with positive and 20 with negative results (5% vs. 3.3%, p < 0.05). Reinfarction was fatal in 5 of 30 patients with positive and in none of 20 with negative results (16.6% vs. 0%, p = 0.07). The relative risk of reinfarction was 1.9. CONCLUSIONS: Dipyridamole echocardiographic positivity identifies patients evaluated early after uncomplicated acute myocardial infarction at higher risk of reinfarction, especially fatal reinfarction.

Prognostic value of pharmacological stress echocardiography in patients with known or suspected coronary artery disease: a prospective, large-scale, multicenter, head-to-head comparison between dipyridamole and dobutamine test. Echo-Persantine International Cooperative (EPIC) and Echo-Dobutamine International Cooperative (EDIC) Study Groups.

OBJECTIVES: The study compared the prognostic value of dipyridamole and dobutamine stress echocardiography in patients with known or suspected coronary artery disease. BACKGROUND: Extensive information is available on the relative diagnostic accuracy of the two tests assessed in a head-to-head fashion, whereas comparative data on their prognostic yield are largely preliminary to date. METHODS: Dipyridamole (up to 0.84 mg/kg over 10 min) atropine (up to 1 mg over 4 min) (DIP) and dobutamine (up to 40 microg/kg/min)-atropine (1 mg over 4 min) (DOB) stress tests were performed in 460 patients with known or suspected coronary artery disease. Patients were followed up for 38+/-21 months. RESULTS: The DIP was negative in 253 and positive in 207 patients. The DOB was negative in 242 and positive in 218 patients. During the follow-up, there were 80 cardiac events. For all cardiac events, the negative and positive predictive value were 83% and 17% for DOB, 84% and 19% for DIP, respectively (p = NS). Considering only cardiac death, by univariate analysis Wall-Motion Score Index (WMSI) at DIP peak dose (chi-square 13.80, p<0.0002) was the strongest predictor, followed by WMSI DOB (chi2 = 8.02, p<0.004) and WMSI at rest (chi2 = 6.85, p<0.008). By stepwise analysis, WMSI at DIP peak dose was the most important predictor (RR [relative risk] 7.4, p<0.0001). CONCLUSIONS: In patients at low-to-moderate risk of cardiac events, pharmacological stress echocardiography with either dobutamine or dipyridamole allows effective and grossly comparable, risk stratification on the basis of the presence, severity and extension of the induced ischemia.

Prognostic value of dobutamine-atropine stress echocardiography early after acute myocardial infarction. Echo Dobutamine International Cooperative (EDIC) Study.

OBJECTIVES: The aim of this multicenter, multinational, prospective, observational study was to assess the relative value of myocardial viability and induced ischemia early after uncomplicated myocardial infarction. BACKGROUND: Dobutamine-atropine stress echocardiography allows evaluation of rest function (at baseline), myocardial viability (at low dose) and residual ischemia (peak dose, up to 40 micrograms with atropine up to 1 mg) in one test. METHODS: Dobutamine-atropine stress echocardiography was performed 12 +/- 5 days (mean +/- SD) after a first uncomplicated acute myocardial infarction in 778 patients (677 men; mean age 58 +/- 10 years) with technically satisfactory rest echocardiographic study results. Patients were followed-up for 9 +/- 7 months. RESULTS: Dobutamine-atropine stress echocardiographic findings were positive for myocardial ischemia in 436 of patients (56%) and negative in 342 (44%). During follow-up, there were 14 cardiac-related deaths (1.8% of the total cohort), 24 (2.9%) nonfatal myocardial infarctions and 63 (8%) hospital readmissions for unstable angina. One hundred seventy-four patients (22%) underwent coronary revascularization (bypass surgery or coronary angioplasty). Spontaneous events occurred in 61 of 436 patients with positive and 40 of 342 patients with negative findings on dobutamine-atropine stress echocardiography (14% vs. 12%, p = 0.3). When only spontaneously occurring events were considered, the most important predictor was myocardial viability (chi-square 9.7). Using the Cox proportional hazards model, only the presence of myocardial viability (hazard ratio [HR] 2.0, p < 0.002) and age (HR 1.03, p < 0.001) were predictive of spontaneously occurring events. When only hard cardiac events were considered, age was the strongest predictor (chi-square 3.6, p = 0.056), followed by wall motion score index (WMSI) at peak dose (chi-square 3.3, p = 0.06) and remote ischemia (chi-square 2.25, p = 0.1). When cardiac death was considered, WMSI at peak dose was the best predictor (HR 9.2, p < 0.0001). CONCLUSIONS: During dobutamine stress, echocardiographic recognition of myocardial viability is more prognostically important than echocardiographic recognition of myocardial ischemia for predicting unstable angina, whereas WMSI at peak stress was the best predictor of cardiac-related death. Different events can be recognized with different efficiency by various stress echocardiographic variables.

The atropine factor in pharmacologic stress echocardiography. Echo Persantine (EPIC) and Echo Dobutamine International Cooperative (EDIC) Study Groups.

OBJECTIVES: This study sought to compare, head to head, the two most popular pharmacologic stress echocardiographic tests--dipyridamole and dobutamine--with state of the art protocols in a large multicenter prospective study. BACKGROUND: In the continuing quest for ideal diagnostic accuracy, pharmacologic stress echocardiography has quickly moved over the years from low to high dose regimens and is currently performed with atropine coadministration. METHODS: Dobutamine (up to 40 microgram/kg body weight per min) plus atropine (up to 1 mg over 4 h) and dipyridamole (up to 0.84 mg/kg per min over 10 h) plus atropine (up to 1 mg over 4 h) stress echocardiography was performed on different days, in random order and within 1 week in 360 patients with chest pain syndrome. Thirteen different echocardiographic laboratories, all fulfilling quality control criteria for stress echocardiographic reading, contributed to the study. RESULTS: No major complications occurred during either test. The test was interrupted before achievement of predetermined end points for limiting side effects in 37 dobutamine-atropine and 7 dipyridamole-atropine stress echocardiographic studies (feasibility 90% vs. 98%, p < 0.01). Diagnostic accuracy was assessed in a subset of 110 patients with no obvious rest dyssynergy (akinesia or dyskinesia) who underwent coronary angiography independently of test results and within 1 week of testing. Significant coronary artery disease (> or = 50% diameter reduction in at least one major coronary vessel by quantitative coronary angiography) was found in 92 patients. Sensitivity for detection of coronary artery disease was 84% (77 of 92) for dobutamine-atropine and 82% (75 of 92) for dipyridamole-atropine stress echocardiography (p = NS), with a specificity of 89% (16 of 18) for dobutamine-atropine and 94% (17 of 18) for dipyridamole-atropine stress echocardiography (p = NS). A significant correlation was present between peak wall motion score index during dipyridamole-atropine and dobutamine-atropine stress echocardiography (r = 0.83, p < 0.0001). CONCLUSIONS: Dobutamine-atropine and dipyridamole-atropine stress echocardiography are safe and feasible, although submaximal studies are more frequent with dobutamine. The two stresses have comparable accuracy in the detection of angiographically assessed coronary artery disease, although dobutamine is marginally more sensitive and dipyridamole marginally more specific. Stratification of the ischemic response in the space domain is also comparable with the two stresses.

A patchwork interspersed sequence is present in a high copy number in the sheep genome.

We have isolated a new interspersed sequence present in a high copy number in the ovine genome. This patchwork sequence, named 3.79 AS1, is part of a larger element encompassing similarities to constant region of reverse transcriptase and to art2 shared with the Bovine Dimer Driven Family (BDDF). The 3.79 AS1 sequence includes homologies to amplification promoting sequences (APS), to a potential origin of bidirectional DNA replication (OBR), to the Alu core sequence motif GGAGGC required for RNA polymerase III promoter function and to the ATGGCTGCCAT sequence that has been shown to be able to induce amplification-dependent transformation in murine cells. Fluorescent in situ hybridization experiments using probes derived from both ends of the 3.79 AS1 sequence showed a widespread signal over all sheep chromosomes, except the Y chromosome. We propose that the structural features of the 3.79 AS1 patchwork sequence, that is likely to be a subfamily of Bov B LINE that invaded the Artiodactyl genome prior to the separation of the Bovidae species, facilitated its massive amplification and dispersion in the ovine genome.

Diagnostic and prognostic value of dipyridamole and dobutamine stress echocardiography in patients with Q-wave acute myocardial infarction.

The aim of this study was to compare dipyridamole and dobutamine stress echocardiography, performed early in patients with acute myocardial infarction (AMI) to evaluate residual ischemia, viability, and prognosis. Fifty patients (mean age 55 +/- 9 years, 47 men, 3 women) with AMI, all treated with thrombolytic therapy, underwent standard dipyridamole and dobutamine tests, within the fifth day of the event. Wall motion score index and the 16 segments model were used to evaluate contractility. Forty-seven patients underwent coronary angiography within the tenth day of the event. The mean follow-up was 24 +/- 12 months. No side effects occurred during both tests. Both dipyridamole and dobutamine tests were positive for ischemia, in 32 and 33 of 47 patients, respectively (sensitivity 73% and 75%; specificity 67% and 67%); these tests induced an improvement of contractility in 23 and 38 of 139 abnormal segments at baseline, respectively (sensitivity 52% and 86%; specificity 100% and 100%). Cardiac events occurred in 26 of 50 patients, 22 with a positive dipyridamole test and 21 with positive dobutamine test. Thus, both tests were feasible, safe, and useful to evaluate residual ischemia, viability, and prognosis. No significant differences were found in sensitivity and specificity between tests.

Doppler study of precordial musical murmurs.

Using phonocardiography, continuous- and pulsed-wave Doppler, 51 patients with precordial "musical" murmurs (49 with cardiac abnormalities) and 21 patients with noisy murmurs were examined. With M-mode echocardiography, fine fluttering of the structure generating the murmur was evident in 23 patients with musical murmurs and in 5 with noisy murmurs. A continuous-wave Doppler spectral signal characterized by parallel harmonics (Doppler musical signal) was evident in all patients with musical murmurs and in none with a noisy murmur. With pulsed-wave Doppler, the musical signal had less defined spectral features because of range ambiguity. Such a signal was experimentally reproduced by activating a diapason bathed in saline solution. The source of the musical murmur was established in all 51 patients by Doppler. The musical signal was associated with a valvular regurgitation signal in 36 patients and with a ventricular septal defect in 1 patient. The musical signal always disappeared when the pulsed-wave Doppler sample volume was placed 2 cm away from the generating structure. In 11 patients with musical murmur examined by color Doppler, no abnormal bidirectional flow signal was observed in the structures generating the signal. In 6 of the patients without valvular regurgitation, no flow disturbance was found. In conclusion, Doppler is valuable in determining the source of musical murmurs, and musical murmurs are caused by a vibrating structure even in the absence of flow turbulence.

Role of GABA(B) receptors in the sedative/hypnotic effect of gamma-hydroxybutyric acid.

The present study was aimed at identifying the receptor systems involved in the mediation of the sedative/hypnotic effect of gamma-hydroxybutyric acid (GHB) in DBA mice. Administration of the putative antagonist of the GHB binding site, 6,7,8,9-tetrahydro-5-hydroxy-5H-benzocyclohept-6-ylideneacetic acid (NCS-382; 50-500 mg/kg, i.p.), significantly increased the duration of loss of righting reflex induced by GHB (1000 mg/kg, i.p.). In contrast, the GABA(B) receptor antagonists, (2S)(+)-5,5-dimethyl-2-morpholineacetic acid (SCH 50911; 25-100 mg/kg, i.p.) and (3-aminopropyl)(cyclohexylmethyl)phosphinic acid (CGP 46381; 12.5-150 mg/kg, i.p.), completely prevented the sedative/hypnotic effect of GHB. SCH 50911 (100 and 300 mg/kg, i.p.) was also capable to readily reverse the sedative/hypnotic effect of GHB (1000 mg/kg, i.p.) in mice that had lost the righting reflex. SCH 50911 (100 mg/kg, i.p.) also completely abolished the sedative/hypnotic effect of the GABA(B) receptor agonist, baclofen. These results indicate that the sedative/hypnotic effect of GHB is mediated by the stimulation of GABA(B) receptors and add further support to the hypothesis that the GABA(B) receptor constitutes a central site of action of GHB.

Left atrial leiomyosarcoma: double occurrence and double recurrence--report of one case.

In October 1996 a 67-year-old man underwent transthoracic and transesophageal echocardiography (TEE) because of dyspnea on exertion and was found to have 2 left atrial cardiac masses. The 2 masses were surgically removed from the atrium and showed histopathologic and ultrastructural features of a leiomyosarcoma. Seven months later a double recurrence of left atrial masses was found with TEE; the patient refused surgery and decided instead to receive chemotherapy. In May 1998 he was in stable condition (New York Heart Association class III), but a further growth of the 2 left atrial masses was observed at TEE. We describe the echocardiographic features of the 2 cardiac masses and the clinical and prognostic implications.

Detection of coronary artery stenoses using breath-hold magnetic resonance coronary angiography. Comparison with conventional x-ray angiography.

PURPOSE: To detect coronary artery stenoses, we compare breath-hold magnetic resonance coronary angiography (MRCA) to conventional coronary angiography (CA). MATERIALS AND METHODS: Sixty-five patients with suspected coronary artery disease underwent MRCA and CA within one week. MRCA examination was performed by using the two-dimensional (2D) breath-hold technique with a fast spoil gradient-echo sequence/spiral. Each imaging sequence was obtained within one breath-hold in expiration (14 seconds of apnoea). The assessment of coronary artery stenoses on magnetic resonance (MR) angiograms was independently performed by two blinded readers and compared to conventional CA images. RESULTS: Three hundred and ninety segments were evaluated by the two imaging techniques. MRCA correctly detected 76 of 88 (86%) stenoses, and recognized 242 of 302 (80%) not affected segments. The Pearson correlation coefficient between MRCA and CA in assessing coronary narrowings was very high: r = 0.85. Despite this the mean difference was 4.5 with a standard error of estimate of 0.21, indicating that MRCA slightly overestimates the degree of stenoses. CONCLUSIONS: Our study showed that 2D breath-hold MRCA is an accurate technique in displaying and quantifying the most significant stenoses in the proximal and middle segments of the coronary arteries.

[Management of ventricular arrhythmia in chronic congestive heart failure]. / La terapia delle aritmie ventricolari nello scompenso cardiaco cronico.

PURPOSE: To evaluate efficacy and indications of therapy for ventricular arrhythmias in patients with chronic congestive heart failure. DESIGN: A review of most significant and recent clinical trials was performed. RESULTS: In patients with severe left ventricular dysfunction, the desirable actions of antiarrhythmic drugs are attenuated and their negative inotropic and proarrhythmic actions are enhanced. Treatment should be limited to patients with malignant ventricular arrhythmias, or to patients considered at high risk. When indicated, amiodarone is usually well tolerated and safe. The prevention of sudden death in patients with heart failure should be based on optimized therapy of pump failure, reducing left ventricle work load and modulating neurohormonal systems with ACE-inhibitors and betablockers drugs. Further, an important role is held by anti-ischemic therapy, revascularization procedures, anticoagulant therapy and prevention of electrolytes unbalances. Patients with sustained of high risk arrhythmias, resuscitated from a cardiac arrest, should be considered for transvenous Implantable Cardioverter Defibrillator (ICD) implant. CONCLUSIONS: Ventricular arrhythmias are common in heart failure patients, represent an important cause of sudden death and the choice of treatment is difficult because of the complexity of underlying mechanisms, frequency of adverse reactions and the severity of left ventricular dysfunction.

Perfiles de personalidad de estudiantes de psicología de universidad privada comparados em similitud y congruencia / Personality profiles of psychology students from a privateuniversity compared by similarity and congruence

En continuidad con los estudios del área de Perfiles de la Cátedra de Psicología Experimental I y II, se llevó a cabo un análisis comparativo de Perfiles de Personalidad en estudiantes de psicología. La muestra fue intencional y autoseleccionada, quedó conformada por 153 estudiantes de Psicología. Se ha utilizado un diseño Descriptivo y Comparado. El instrumento utilizado fue el Inventario Multifásico de la Personalidad Minnesota-2 (MMPI-2). Los resultados reportan que existe un patrón de personalidad con similitudes muy acentuadas en los estudiantes de la carrera de psicología, independiente del curso al que pertenecen, y en comparación a los perfiles de años anteriores (n = 152, muestra 2001: n=168, muestra 2007: y n= 101 muestra 2008).

In continuity with the studies of the area of Profiles of the Professorship of Experimental Psychology I and II, a comparative analysis of Profiles of Personality in students of psychology was carried out. The sample was intentional and autoseleccionada, remained conformed by 153 (166) students of Psychology. A Descriptive design has been utilized and Compared. The instrument utilized was the Polyphase Inventory of the Personality Minnesota-2 (MMPI-2). The results report that a boss of personality with similarities exists very accentuated in the students of the career of psychology, independent of the course to which they belong, and in comparison to the profiles of previous years (n = 152 sample 2001; n = 168, sample 2007 and n = 101 sample 2008).

[Glycinamide derivatives of norbornane]. / Glicinamidi derivate dal norbornano.

Three groups of glycinamides derivatived respectively from 4-aminomethyl-2,2,3-trimethylnorbornane, from 1-aminomethyl-2,2-dimethyl-3-methylennorbornane and from 1-aminomethyl-2,2,3-trimethylnorbornane are prepared and described.

[Study on the amide of 2-chlorobornan-4-carboxylic acid]. / Studio sull'amide dell'acido 2-clorobornan-4-carbossilico

During the study of the transpositions undergone by the amide of canphen-4-carboxylic acid on treatment with concentrated hydrochloric acid, the formation of the amide of 2-chlorobornan-4-carboxylic acid alone, arising in two polymorphous forms, has been confirmed. Its reduction produced 2-chloro-4-aminomethylbornane; the detachment of hydrochloric acid at the amide of canphen-1-carboxylic acid.

Modificación de la política de pagos de comisiones estándar a escalar y la satisfacción en vendedores / Changes in the policy of standard commission´s payments to scalar and seller´s satisfaction

Se plantea una investigación con un diseño cuasi-experimental intragrupo prepost evaluación, cuyo objetivo es demostrar que la modificación de la política de pago de comisiones, de estándar a escalar (VI), influye en el nivel de satisfacción (VD) de una muestra de 40 vendedores de una compañía telefónica, que será medida por el “Cuestionario De Satisfacción Laboral S10/12” (Meliá y Peiró, 1998). Se aplicará un análisis estadístico descriptivo e inferencial, para comprobar la relación funcional entre la VI (modificación de la política de pago de comisiones, de estándar a escalar) y la VD (aumento del nivel de satisfacción de los vendedores), recurriendo a la prueba t de Student para una sola muestra, con un nivel de significación de 0,05.

[Doppler echocardiography in assessing mechanical and biological heart valve prostheses]. / Ecocardiografia Doppler nella valutazione di protesi valvolari meccaniche e biologiche.

The study was performed to assess Doppler echocardiographic features of mitral and aortic prosthetic valves of different types with both normal and abnormal function. Two hundred and twenty-three patients with 250 prostheses were studied. Two hundred eight valves (111 mitral, 95 aortic and 2 tricuspid) were considered to be functioning normally after clinical examination, phonocardiography and M-mode and 2D echocardiography. This group enabled us to define normal Doppler echocardiographic findings for different types of prosthesis. In mitral position, peak (p) and mean (m) gradients were lower for disc prostheses and higher for ball and biological prosthetic valves; values of effective orifice area (A), calculated by pressure half-time method, were lower for biological and ball prostheses and higher in disc valves. Results were as follows: St. Jude (p 10.6 mmHg, m 3.9 mmHg, A 2.7 cm2), Duromedics (p 10.6, m 4.3, A 2.8), Björk-Shiley (p 10.4, m 4, A 2.3), Omniscience (p 14.2, m 6.2, A 2.1), Starr-Edwards (p 15.9, m 5.4, A 2.1), Hancock (p 14.7, m 6, A 2), Carpentier (p 13.2, m 5.4, A 1.9). Mild regurgitation, considered "physiological", was found in 2/8 Carpentier valves and in 3/34 St. Jude prostheses. In aortic valves lower peak gradients were found in Lillehei (18.3 mmHg), St. Jude (23.8 mmHg), Björk-Shiley (26 mmHg), Duromedics (27 mmHg) and higher values in Starr-Edwards (30.2 mmHg), Hancock (30 mmHg) and Omniscience (35.5 mmHg) prostheses. Mild regurgitation, considered "physiological", was found in 17% of Omniscience valves, 21% of Hancock, 33% of Duromedics, 45% of St. Jude, 60% of Björk-Shiley prostheses. Hancock mitral valves implanted for over 7 years had a mean gradient higher than valves with a shorter period of implantation (7.6 vs 4.85 mmHg, p less than 0.1), whereas the effective orifice area was similar. Hancock aortic valves implanted for over 7 years had a peak gradient slightly higher than the other group (implantation less than 7 years previously), but the difference was not statistically significant. Forty-two valves (19 aortic and 23 mitral) were considered to be malfunctioning. Regurgitation Doppler signals of malfunctioning valves appeared different from those of "physiological" reverse flow; in the former cases forward gradient was higher than normal prostheses. In stenotic aortic prostheses, peak systolic gradient was greatly increased; in stenotic mitral prostheses, a very significant increase in mean gradient and a great decrease in effective orifice area were found. In 14 patients who underwent surgical re-operation and in the patient who died before operation, Doppler echocardiographic findings were confirmed.(ABSTRACT TRUNCATED AT 400 WORDS)