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Biomedical subjects

S De Castro

Publications and source records attributed to S De Castro.

At least 19 recordsLinked to original sources
PubMed2006

A case series of young stroke in Rome.

In this hospital case series study we enrolled 394 consecutive ischemic stroke patients aged 14-47 years, all of whom were submitted to a diagnostic protocol. We evaluated the incidence of cerebral ischemia in young adults, as well as the risk factors and the etiopathogenesis of this pathology. Modified diagnostic criteria adopted from the TOAST and Baltimore-Washington Cooperative Young Stroke Study were used for the etiologic classification. The crude annual incidence rate was 8.8/100,000 (95% CI 7.7-9.9), which is in keeping with the rates reported in comparable registries. Risk factors were distributed as follows: smoking in 56% of patients, hypertension in 23%, dyslipidemia in 15%, migraine in 26%, and diabetes mellitus in 2%. Oral contraceptives were being taken by 38% of the women enrolled. The etiology of stroke in the patients was as follows: cardioembolism in 34%, atherothrombosis in 12%, non-atherosclerotic vasculopathies in 14% (including arterial dissection in 12%), other determined causes in 13%, lacunar stroke in 2.5%, migraine in 1%, and undetermined causes in 24%. Despite its biased sampling frame, this large hospital case series, in which risk factor distribution and etiopathogenesis were investigated, stresses the need for an adequate diagnostic approach in young ischemic patients.

Adolescent↗
PubMed2006

TSAO derivatives, inhibitors of HIV-1 reverse transcriptase dimerization: recent progress.

There is an urgent need for the development of new and safer drugs for the treatment of HIV (human immunodeficiency virus) infection, active against the currently resistant viral strains or directed to novel targets in the viral replicative cycle that may be useful for multiple drug combination. TSAO derivatives are a peculiar group of highly functionalized nucleosides that belong to the so-called nonnucleoside RT inhibitors (NNRTIs). HIV-1 reverse transcriptase (RT) is a key enzyme that plays an essential and multifunctional role in the life cycle of the virus and thus represents a key target for antiviral chemotherapeutic intervention. The dimeric form of the enzyme is absolutely required for all enzymatic activities. Thus, the process of dimerization and subsequent maturation into the p66/p51 heterodimer is essential for a fully functional RT and constitutes a target for therapeutic intervention, however to date such agents have not been developed. TSAO molecules are a peculiar group of non-nucleoside RT inhibitors that exert a unique selectivity for HIV-1 through a specific interaction with the p51 subunit of HIV-1 RT. They interact at the p66/p51 heterodimer interface of the enzyme. They were the first small non peptidic molecules shown to interfere with the dimerization process of the enzyme. This review covers the recent work within this family of compounds aimed at enhancing their interaction with the dimer interface of HIV-1 RT.

Binding Sites↗
PubMed2006

Noninvasive testing for coronary artery disease in women.

Coronary artery disease is a major cause of morbidity and mortality for women in North America and Europe. Given the significance of coronary disease as a public health problem among women, accurate diagnosis of this condition is of great importance. Several noninvasive testing modalities are available for the diagnosis of coronary heart disease. An understanding of gender-based differences related to noninvasive cardiac testing is useful in order to optimally utilize these tests and improve detection and clinical outcomes in women.

Carotid Arteries↗
PubMed2004

Limits for the central production of Theta+ and Xi(--)pentaquarks in 920-GeV pA collisions.

We have searched for Theta+(1540) and Xi(--)(1862) pentaquark candidates in proton-induced reactions on C, Ti, and W targets at midrapidity and square root of s = 41.6 GeV. In 2 x 10(8) inelastic events we find no evidence for narrow (sigma approximately 5 MeV) signals in the Theta+ --> pK0(S) and Xi(--) --> Xi- pi- channels; our 95% C.L. upper limits (UL) for the inclusive production cross section times branching fraction B dsigma/dy/(y approximately 0) are (4-16) mub/N for a Theta+ mass between 1521 and 1555 MeV, and 2.5 mub/N for the Xi(--). The UL of the yield ratio of Theta+/Lambda(1520) < (3-12)% is significantly lower than model predictions. Our UL of B Xi(--)/Xi(1530)0 < 4% is at variance with the results that have provided the first evidence for the Xi(--).

Journal Article↗
PubMed2002

Barkas effect for antiproton stopping in H2.

We report the stopping power of molecular hydrogen for antiprotons of kinetic energy above the maximum (approximately 100 keV) with the purpose of comparing with the proton one. Our result is consistent with a positive difference in antiproton-proton stopping powers above approximately 250 keV and with a maximum difference between the stopping powers of 21%+/-3% at around 600 keV.

Journal Article↗
PubMed2001

Bulls-eye display and quantitation of myocardial perfusion defects using three-dimensional contrast echocardiography.

Three-dimensional (3-D) myocardial contrast echocardiography (MCE) is able to derive parallel cutting planes of the left ventricle (LV). However, assessment of the site and extent of myocardial perfusion abnormalities has to rely on the reader's 3-D mental reconstruction from the tomograms, and a manual approach has to be employed for quantitative analysis. The objective of this study was to explore the display and quantitative capability of a bulls-eye format from contrast 3-D MCE in the assessment of perfusion abnormalities derived from a canine model of acute myocardial infarction (MI). Three-dimensional MCE data were acquired sequentially in a rotational scanning format during triggered harmonic imaging with an intravenous contrast agent. Reconstructed short-axis views of the LV were aligned in a bulls-eye format with the apex as the inner most ring. The total LV was divided into 120 sectors. The number of sectors with lack of contrast enhancement was used to derive the percent of the LV (%LV) with perfusion defect and was compared with the extent of MI calculated from postmortem triphenyl tetrazolium chloride (TTC) staining. The perfusion defect regions shown on bulls-eye images corresponded correctly with the territories of the occluded coronary arteries. Three-dimensional MCE perfusion defect mass (19.2 +/- 6.0 %LV) correlated well with anatomic MI mass (19.3 +/- 5.6 %LV; r = 0.92, SEE = 2.3%, mean differential = 0.1 +/- 2.4%). We conclude that bulls-eye display of contrast 3-D MCE demonstrates the site and extent of perfusion abnormalities in an easily appreciable manner. It also allows fast and accurate assessment of endangered myocardium.

Animals↗
PubMed2001

Current status of three-dimensional echocardiography.

Volume rendered three-dimensional echocardiography (3DE), a rapidly emerging imaging method, offers clinicians and surgeons a new perspective for visualizing the heart. Using both transthoracic and transesophageal approach this new methodology enables qualitative and quantitative information of cardiac disorders to be obtained. 3DE image projections have allowed visualization of intracardiac structures and great vessels and delineation of their pathology in a comprehensive manner. Experimental and clinical studies suggest that 3DE is likely to play a valuable role in the evaluation of various cardiac and flow disorders and in planning interventions and surgery. In addition, 3DE has been applied to derive quantitative measurements of volume, mass and dimensions of the left and right ventricles and also other cardiac lesions, such as atrial and ventricular septal defects. Every aspect of 3DE is in continuous evolution. Faster and more highly automated image processing could make the technique more easily applicable in the clinical scenario.

Echocardiography, Three-Dimensional↗
PubMed2000

Global left ventricular shape is not altered as a consequence of physiologic remodeling in highly trained athletes.

It is uncertain whether left ventricular (LV) shape is altered as a consequence of intensive athletic conditioning. We assessed LV dimensions and shape by Fourier analysis from digitized LV endocardial borders in 22 elite rowers and 14 untrained controls. Athletes had greatly increased LV cavity dimension, wall thickness, volume, and mass; however, LV shape was normal in athletes, and associated with normal ejection fraction and diastolic filling pattern.

Adolescent↗
PubMed2000

The echocardiography laboratory in the informatic era.

This article overviews the latest progress in echocardiography in this informatic era. We will present new, different techniques available in clinical settings for qualitative and quantitative evaluation of global and regional left ventricular function, showing their helpfulness in clinical work. We will also report our personal experiences with 3-dimensional (3-D) echocardiography in quantification of left ventricular total mass and left-ventricular dysfunctional mass, and in evaluation of left-ventricular parietal stress. Finally, we will show how the organization of a modern echocardiography laboratory is changing after informatic progress: we will report our personal experiences about transmission of echocardiography data between 2 work stations, located in different places; in this way we can realize an informatic web, which can go out from the single echocardiography laboratories and move toward intradepartment and interdepartment services.

Echocardiography, Three-Dimensional↗
PubMed2000

Patent foramen ovale and its embolic implications.

This study investigates the usefulness of the echocardiographic characteristics of patent foramen ovale (PFO) in the stratification of stroke recurrence risk in patients with acute ischemic cerebral disease. Shunting at rest and a highly mobile fossa ovalis membrane are more frequently detected in stroke patients with PFO as the only identifiable cause of embolism. For PFO patients with both rest patency and membrane mobility > 6.5 mm, the risk of stroke/transient ischemic attack recurrence was 7.6% (95% CI, 0-18.0) at 12 months and 12.5% (95% CI, 0-26.1) at 24 months (p = 0.05). The association of both rest patency and high membrane mobility seems to identify those stroke patients with PFO at higher risk for further brain embolism.

Case-Control Studies↗
PubMed2000

Three-dimensional transesophageal echocardiography (TEE) and other future directions.

As faster imaging systems enter the market, three-dimensional echocardiography is gearing up to become a useful tool in assisting the clinician to image the heart in many innovative projections. What started out as a novel idea of displaying a three-dimensional anatomic picture of the heart now provides a multitude of views of the heart and its structures. Information gained from anatomic and dynamic data has helped clinicians and surgeons in making clinical decisions. In the future, this imaging modality may become a routine imaging modality for assessing cardiac pathology and may serve to increase understanding of the dynamics of the heart.

Echocardiography, Doppler, Color↗
PubMed2000

Harmonic imaging with Levovist for transthoracic echocardiographic reconstruction of left ventricle in patients with post-ischemic left ventricular dysfunction and suboptimal acoustic windows.

BACKGROUND: Attempts to perform transthoracic 3-dimensional echocardiography (3DE) are often encumbered by poor definition of chamber borders in adult patients who have technically suboptimal acoustic windows. METHODS: To assess whether harmonic imaging (HI) and contrast agents can facilitate transthoracic 3DE assessment of the left ventricle, we used fundamental imaging (FI), HI alone, and HI coupled with the echo-enhancing contrast agent Levovist in 15 consecutive patients with post-ischemic left ventricular (LV) dysfunction and technically difficult windows. Dynamic 3DE image data sets were obtained at 5-degree angles (36 slices) from a transthoracic apical view. From these data a total of 240 myocardial segments were analyzed with the use of dynamic short-axis paraplane slices at basal, middle, and apical LV levels (standard 16 segment model). For border definition, each segment was scored in random sequence on the following scale by 2 independent investigators: 0 = not seen, 1 = suboptimal visualization, and 2 = well defined. RESULTS: Our results showed a significant increase in the number of well-visualized segments when harmonic mode combined with Levovist injection was compared with FI and HI alone. CONCLUSION: Harmonic imaging alone improves LV assessment by 3DE when compared with FI. Contrast imaging in which Levovist is added to HI further improves the capability of transthoracic tomographic 3DE in the visualization of LV myocardial segments. This could allow 3DE by transthoracic windows to be used more widely in adults for the evaluation of LV volume and function.

Adult↗
PubMed2000

Diagnostic accuracy of transthoracic and multiplane transesophageal echocardiography for valvular perforation in acute infective endocarditis: correlation with anatomic findings.

We evaluated the diagnostic accuracy of transthoracic and multiplane transesophageal echocardiography (TTE and TEE, respectively) for assessing valvular perforation during active infective endocarditis by correlating the results of TTE and TEE with anatomic findings of 88 valves examined at surgery or autopsy. Compared with TEE, TTE has a low diagnostic sensitivity in the detection of this complication and, in the presence of hemodynamic instability, multiplane TEE should be performed directly.

Adult↗
PubMed2000

Modification of cardiac function in cirrhotic patients with and without ascites.

OBJECTIVES: Abnormalities in cardiac function have been reported in liver cirrhosis, suggesting a latent cardiomyopathy in these patients. In this study we investigated cardiac function in cirrhotic patients and in controls. METHODS: A total of 20 cirrhotic patients without previous or ongoing ascites, 20 cirrhotic patients with moderate-to-severe ascites, and 10 healthy controls were studied by two-dimensional Doppler echocardiography. Cardiac dimensions and left and right ventricular function were evaluated. The left ventricular geometric pattern was calculated according to Ganau's criteria. Diastolic function was evaluated by the peak filling velocity of E wave and A wave, E/A ratio, and deceleration time of E wave. The pulmonary systolic arterial pressure was also estimated in patients with tricuspid insufficiency. RESULTS: Right and left atrium and right ventricle diameters were significantly enlarged in cirrhotic patients versus controls. E/A ratio was decreased (p < 0.05) in patients with ascites (0.9 +/- 0.2) versus those without ascites (1.3 +/- 0.4) and controls (1.3 +/- 1). The estimated pulmonary systolic arterial pressure was slightly elevated in patients with ascites (35 +/- 5 mm Hg, six patients) versus those with no ascites (28 +/- 5, 10 patients) and controls (27 +/- 8, 6 controls, analysis of variance, p < 0.05). The pattern of left ventricular geometry was normal in the majority of patients. Nitrite and nitrate levels were increased in cirrhotics irrespective of the presence of ascites. CONCLUSIONS: Liver cirrhosis is associated with enlarged right cardiac chambers. Diastolic dysfunction and mild pulmonary hypertension are evident in cirrhotic patients with ascites. These changes do not depend on variations in the left ventricular geometry.

Ascites↗
PubMed2000

Morphological and functional characteristics of patent foramen ovale and their embolic implications.

BACKGROUND AND PURPOSE: Transesophageal echocardiography (TEE) has detected a high prevalence of patent foramen ovale (PFO) in stroke patients, but the clinical implications of the distinctive characteristics of this patency are still a matter of debate. METHODS: We studied 350 patients with acute ischemic stroke or transient ischemic attack (TIA) within 1 week of admission. Of these, 101 (29%) were identified by contrast TEE to have a PFO; 86 patients (25%) were cryptogenic stroke patients, and 163 were excluded because of the presence of a definite or possible arterial or clinical evidence of a source of emboli or small-vessel disease. Thirteen PFO subjects without a history of embolism were designated as the control group. All PFO and cryptogenic stroke patients were followed up by neurological visits. RESULTS: Compared with controls, PFO patients with acute stroke or TIA more frequently presented with a right-to-left shunt at rest and a higher membrane mobility (P:<0. 05). Patients with these characteristics were considered to be at high risk. During a median follow-up period of 31 months (range, 4 to 58 months), 8 PFO and 18 cryptogenic stroke patients experienced recurrent cerebrovascular events. The cumulative estimate of risk of cerebrovascular event recurrence at 3 years was 4.3% (95% confidence interval [CI], 0% to 10.2%) for "low-risk" PFO patients, 12.5% (95% CI, 0% to 26.1%) for "high-risk" PFO patients, and 16.3% (95% CI, 7. 2% to 25.4%) for cryptogenic stroke patients (high-risk PFO versus low-risk PFO, P:=0.05). CONCLUSIONS: The association of right-to-left shunting at rest and high membrane mobility, as detected by contrast TEE, seems to identify PFO patients with cerebrovascular ischemic events who are at higher risk for recurrent brain embolism.

Aorta↗