Gene therapy for restenosis after balloon angioplasty and stenting

Percutaneous coronary revascularization is an increasingly attractive alternative to medical therapy and surgical revascularization for coronary artery disease. The leading drawback of this procedure continues to be restenosis-the process of late arterial renarrowing at the site of initially successful intervention. Restenosis after balloon angioplasty seems to be determined primarily by the direction and magnitude of vessel wall remodeling. In contrast, the major limitation of stent implantation is the initiation of neointimal tissue proliferation within and adjacent to the stent. The goal of this review is to summarize recent laboratory and clinical investigations of the transmission of mitogenic signals from the membrane to the nucleus in smooth muscle cells. The mechanisms responsible for restenosis after balloon angioplasty and stenting and the possibility of transferring specific genes into somatic vascular cells with molecular tools to inhibit smooth muscle cell proliferation also will be reviewed.

Emerging antithrombotic treatments for acute coronary syndromes

In the last few years the hypothesis of coronary thrombosis, frequently triggered by plaque ulceration or fissuration, has gained wide acceptance as one of the key events in the pathophysiology of acute coronary syndromes. Plaque ulceration may activate both platelets and the coagulation cascade via exposure of a variety of substances, such as von Willebrand factor and tissue factor. It has been demonstrated that aspirin reduces mortality and improves the prognosis of patients with such syndromes. More recently, newer drugs have been identified for the treatment of acute coronary syndromes; in particular, platelet glycoprotein IIb/IIIa inhibitors have been found to be more effective than aspirin in a variety of clinical conditions, such as unstable angina, acute myocardial infarction, and coronary angioplasty. Other drugs with different mechanisms of action will be soon available for large scale clinical trials.

Exercise capacity in hypertrophic cardiomyopathy depends on left ventricular diastolic function

Some studies have demonstrated that left ventricular (LV) diastolic function is the principal determinant of impaired exercise capacity in hypertrophic cardiomyopathy (HC). In this study we sought the capability of echocardiographic indexes of diastolic function in predicting exercise capacity in patients with HC. We studied 52 patients with HC while they were not on drugs;12 of them had LV tract obstruction at rest. Diastolic function was assessed by M-mode and Doppler echocardiography by measuring: (1) left atrial fractional shortening, and the slope of posterior aortic wall displacement during early atrial emptying on M-mode left atrial tracing; and (2) Doppler-derived transmitral and pulmonary venous flow velocity indexes. Exercise capacity was assessed by maximum oxygen consumption by cardiopulmonary test during cycloergometer upright exercise. Maximum oxygen consumption correlated with the left atrial fractional shortening (r = 0.63, p <0.001), the slope of posterior aortic wall displacement during early atrial emptying (r = 0.55, p <0.001), age (r = -0.50; p <0.001), pulmonary venous diastolic anterograde velocity (r = 0.41, p <0.01), and the systolic filling fraction (r = -0.43; p <0.01). By stepwise multiple linear regression analysis, left atrial fractional shortening and the pulmonary venous systolic filling fraction were the only determinants of the maximum oxygen consumption (multiple r = 0.70; p <0.001). Exercise capacity did not correlate with Doppler-derived transmitral indexes. Thus, in patients with HC, exercise capacity was determined by passive LV diastolic function, as assessed by the left atrial M-mode and Doppler-derived pulmonary venous flow velocities.

Activation of the protein kinase Akt/PKB by the formation of E-cadherin-mediated cell-cell junctions. Evidence for the association of phosphatidylinositol 3-kinase with the E-cadherin adhesion complex

E-cadherins are surface adhesion molecules localized at the level of adherens junctions, which play a major role in cell adhesiveness by mediating calcium-dependent homophylic interactions at sites of cell-cell contacts. Recently, E-cadherins have been also implicated in a number of biological processes, including cell growth and differentiation, cell recognition, and sorting during developmental morphogenesis, as well as in aggregation-dependent cell survival. As phosphatidylinositol (PI) 3-kinase and Akt play a critical role in survival pathways in response to both growth factors and extracellular stimuli, these observations prompted us to explore whether E-cadherins could affect intracellular molecules regulating the activity of the PI 3-kinase/Akt signaling cascade. Using Madin-Darby canine kidney cells as a model system, we show here that engagement of E-cadherins in homophylic calcium-dependent cell-cell interactions results in a rapid PI 3-kinase-dependent activation of Akt and the subsequent translocation of Akt to the nucleus. Moreover, we demonstrate that the activation of PI 3-kinase in response to cell-cell contact formation involves the phosphorylation of PI 3-kinase in tyrosine residues, and the concomitant recruitment of PI 3-kinase to E-cadherin-containing protein complexes. These findings indicate that E-cadherins can initiate outside-in signal transducing pathways that regulate the activity of PI 3-kinase and Akt, thus providing a novel molecular mechanism whereby the interaction among neighboring cells and their adhesion status may ultimately control the fate of epithelial cells.

Activated platelets and leucocytes cooperatively stimulate smooth muscle cell proliferation and proto-oncogene expression via release of soluble growth factors

BACKGROUND

Previous studies indicate that platelets and leucocytes might contribute to the development of neointimal hyperplasia following arterial injury. The present study was aimed at further investigating the role of platelets and leucocytes, alone or in combination, in promoting vascular smooth muscle cell (SMC) proliferation in vitro, focusing on the relative contribution of different soluble growth factors released by these cells, and on the ability to induce proto-oncogene expression, such as c-fos.

METHODS

SMCs from rabbit aortas, made quiescent by serum deprivation, were stimulated with either activated platelets, leucocytes, or both, separated from SMCs by a membrane insert. SMC proliferation was evaluated by measuring the incorporation of 3H-thymidine. The relative contribution of different platelet-derived mediators to SMC growth was evaluated by adding either ketanserin, a 5-HT2 receptor antagonist, R68070, a TxA2 receptor antagonist, BN52021, a platelet activating factor (PAF) receptor antagonist, and trapidil, a platelet derived growth factor (PDGF) receptor antagonist. The role of different leucocyte sub-populations (neutrophils and monocytes + lymphocytes) was also determined in additional experiments.

RESULTS

SMC proliferation was significantly increased by activated platelets to 360 +/- 9% of control values (P < 0.05). This effect was reduced by ketanserin, R68070, BN 52021 or trapidil. Whole leucocytes, neutrophils or lymphocytes + monocytes also increased SMC proliferation with respect to control experiments. Simultaneous stimulation of SMCs by platelets and whole leucocytes was associated with a significant greater increase in SMC proliferation as compared to SMC stimulated with platelets or leucocytes alone. c-fos expression, almost undetectable in unstimulated SMCs, was markedly increased by activated platelets or leucocytes.

CONCLUSIONS

Activated platelets promote SMC proliferation in vitro via release of soluble mediators, including serotonin, thromboxane A2 PAF and PDGF; activated leucocytes also induce a significant SMC proliferation and exert an additive effect when activated together with platelets; SMCs stimulated with activated platelets and leucocytes show an early expression of the proto-oncogene c-fos.

The small GTPases Rab5a, Rab5b and Rab5c are differentially phosphorylated in vitro

Rab GTPases play a fundamental role in the regulation of membrane traffic. Three different Rab5 isoforms have been reported but no differences in their function in endocytosis have been discovered. As the Rab5 isoforms show a conserved consensus site for Ser/Thr phosphorylation, we investigated whether this site was phosphorylated. Here, we report that the three Rab5 proteins are differentially recognized by different kinases. Rab5a is efficiently phosphorylated by extracellular-regulated kinase 1 but not by extracellular-regulated kinase 2, while cdc2 kinase preferentially phosphorylates Ser-123 of Rab5b. These findings strongly suggest that phosphorylation could be important to differentially regulate the function of the Rab5 isoforms.

Rest-injected 201thallium in the evaluation of myocardial viability

In recent years 201thallium scintigraphy at rest has been used for evaluating myocardial viability in patients with chronic ischemic coronary artery disease and left ventricular dysfunction. Based on the assumption that reversible myocardial dysfunction arises from chronic hypoperfusion (hibernation), resting 201thallium scintigraphy is performed by acquiring two sets of images, one early after tracer injection and a second following 3 to 4 hours to allow for the redistribution process to take place. However, redistribution of 201thallium following injection at rest rarely occurs, and in many studies it does not significantly contribute to the identification of reversibly dysfunctional myocardium. In fact, current interpretation of resting 201thallium scintigraphy is based on the measurement of regional tracer uptake on the redistribution images, using a fixed threshold value (most commonly from 50 to 65% of maximal uptake) that arbitrarily identify viable (presumably reversible) and nonviable (presumably irreversible) dysfunctional myocardium. The practical implication of this approach is relevant as it implies that analysis of a single set of images is adequate for viability information. As with other nuclear techniques, sensitivity of 201thallium scintigraphy for predicting functional recovery following revascularization is very high, but specificity is suboptimal, reflecting the identification of substantial residual tracer uptake in territories that will remain dysfunctional at rest following successful revascularization. Inadequate timing of follow-up functional evaluation, ongoing degeneration of hibernating myocytes, admixture of necrotic and normal myocardium in dysfunctional areas are among factors that likely explain this discrepancy. It remains to be evaluated in future studies whether revascularization of these areas that contain viable myocardium but where resting function does not change, may also contribute to the beneficial effects of revascularization in patients with left ventricular dysfunction.

A network of mitogen-activated protein kinases links G protein-coupled receptors to the c-jun promoter: a role for c-Jun NH2-terminal kinase, p38s, and extracellular signal-regulated kinase 5

The expression of the c-jun proto-oncogene is rapidly induced in response to mitogens acting on a large variety of cell surface receptors. The resulting functional activity of c-Jun proteins appears to be critical for cell proliferation. Recently, we have shown that a large family of G protein-coupled receptors (GPCRs), represented by the m1 muscarinic receptor, can initiate intracellular signaling cascades that result in the activation of mitogen-activated protein kinases (MAPK) and c-Jun NH2-terminal kinases (JNK) and that the activation of JNK but not of MAPK correlated with a remarkable increase in the expression of c-jun mRNA. Subsequently, however, we obtained evidence that GPCRs can potently stimulate the activity of the c-jun promoter through MEF2 transcription factors, which do not act downstream from JNK. In view of these observations, we set out to investigate further the nature of the signaling pathway linking GPCRs to the c-jun promoter. Utilizing NIH 3T3 cells, we found that GPCRs can activate the c-jun promoter in a JNK-independent manner. Additionally, we demonstrated that these GPCRs can elevate the activity of novel members of the MAPK family, including ERK5, p38alpha, p38gamma, and p38delta, and that the activation of certain kinases acting downstream from MEK5 (ERK5) and MKK6 (p38alpha and p38gamma) is necessary to fully activate the c-jun promoter. Moreover, in addition to JNK, ERK5, p38alpha, and p38gamma were found to stimulate the c-jun promoter by acting on distinct responsive elements. Taken together, these results suggest that the pathway linking GPCRs to the c-jun promoter involves the integration of numerous signals transduced by a highly complex network of MAPK, rather than resulting from the stimulation of a single linear protein kinase cascade. Furthermore, our findings suggest that each signaling pathway affects one or more regulatory elements on the c-jun promoter and that the transcriptional response most likely results from the temporal integration of each of these biochemical routes.

Interaction cloning and characterization of the cDNA encoding the human prenylated rab acceptor (PRA1)

Rab proteins are small GTPases involved in the regulation of intracellular membrane traffic in mammalian cells. In order to find Rab-interacting proteins we performed a two-hybrid screening using a human brain cDNA library. Here we report the isolation of a full-length human cDNA clone coding for a protein of 185 amino acids. This protein interacts strongly with the Rab4b, Rab5a, and Rab5c proteins and weakly with Rab4a, Rab6, Rab7, Rab17, and Rab22 in the two-hybrid assay. Comparison with the Data Bank revealed that this clone represents the human homolog of the previously isolated rat Prenylated Rab Acceptor (rPRA1). Analysis of mRNA expression shows a single abundant mRNA of about 0.8 kb ubiquitously expressed. Western blot analysis of the overexpressed protein shows a band of the expected size equally distributed between cytosol and membranes.

[Therapy with nitro derivatives and the development of tolerance: a comparative study with stress ECG and dipyridamole ECG]

The ECG stress test represents the most commonly-used technique to evaluate the occurrence of nitroglycerin tolerance. It acts by increasing cardiac O2 demand with resulting insufficient blood flow through a stenotic coronary artery and development of cardiac ischemia. However, other tests are also potentially suitable, such as the ECG-dipyridamole test. The aim of the present study was to evaluate the acute response of ECG-dipyridamole and ECG-stress tests to nitroglycerin. In particular, the development of nitroglycerin tolerance during chronic therapy was evaluated with both tests in patients with stable angina. Eleven patients (8 men and 3 women) with CAD proven by a previous coronarography, a known history of stable angina within at least six months and a positive response to both the tests were studied. At the end of a seven-day wash-out period, all patients were positive to initial ECG-stress and ECG-dipyridamole tests; after 3 days a new evaluation was carried out (Effort 0 and Dip 0) and this confirmed the previous results. We performed a randomized trial in two phases: acute and chronic therapy. In the acute phase, all patients underwent ECG-stress and ECG-dipyridamole tests (Effort 1 and Dip 1) in a randomized fashion one day apart, four hours after administration of a 10 mg/24 h nitroglycerin patch. The chronic phase consisted of 25 days of continuous treatment with a nitroglycerin patch. The two tests (Effort 2 and Dip 2) were always repeated after four hours of the morning therapy. Nitroglycerin does not modify the hemodynamic response to dipirydamole in either acute or chronic treatment. Lastly, our data confirm the efficacy of nitroglycerin on stress and dipyridamole tests after acute administration. Nitroglycerin tolerance is confirmed by both tests although with different patterns. ECG stress test showed nitroglycerin tolerance because time to ischemia and max ST deteriorated during chronic therapy. Moreover, the ECG-dipyridamole test showed nitroglycerin tolerance because five patients with a negative acute test (Dip 1) became positive during chronic therapy (Dip 2).

Determinants of aortic artifacts during transesophageal echocardiography of the ascending aorta

BACKGROUND

The origin of artifacts of the ascending aorta during transesophageal echocardiography has not been widely studied. This study was undertaken to investigate in vivo whether anatomic features could determine the appearance of artifacts.

METHODS AND RESULTS

Transesophageal echocardiograms of 46 patients studied for suspected dissection with proven diagnosis (30 patients with and 16 without ascending aortic dissection) were reviewed. The incidence of artifacts was 46%, and it was similar in patients with and those without dissection (chi-square 0.516; P = not significant). Artifacts were located in the aortic lumen twice as far from the transducer as the atrial-aortic interface. The aortic diameter was larger in patients with than in those without artifacts (6.4 +/- 1.1 vs 4.2 +/- 0.9 cm, P <.001). An aortic diameter >5 cm and an atrial-aortic ratio </=0.6 predicted the artifact appearance with good sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy; these parameters reached a value of 100% by analysis only of patients without dissection.

CONCLUSIONS

An ascending aortic diameter >5.0 cm that exceeds the left atrial diameter with an atrial-aortic ratio </=0.6 creates in vivo the conditions for the reverberation of the atrial-aortic interface within the aorta. Therefore, in patients with such anatomic features, artifacts must be suspected in the presence of linear structures within the aorta.

Influence of left ventricular cavity size on clinical presentation in hypertrophic cardiomyopathy

The aim of this study was to assess whether left ventricular (LV) cavity size relates to functional impairment and syncope in patients with hypertrophic cardiomyopathy (HC). LV diastolic dysfunction influences functional limitation in HC. A reduced LV end-diastolic dimension may underlie impaired diastolic properties and be implicated in hemodynamic syncope. Eighty-two consecutive patients with HC (off drugs, in sinus rhythm) underwent echocardiography to measure LV end-diastolic dimension in the short-axis view (indexed to the body surface area) and radionuclide angiography (n = 50) to calculate peak filling rate (normalized to stroke counts/s). Patients in New York Heart Association functional classes II to IV had smaller LV end-diastolic dimension (23.2 +/- 2.6 vs 25.5 +/- 2.5 mm/M2, p = 0.0001) and lower peak filling rate (4.3 +/- 1.4 vs 5.1 +/- 1.3 stroke counts/s, p = 0.036) than those in New York Heart Association class I. LV end-diastolic diameter was correlated to peak filling rate (r = 0.37; p = 0.008). The most potent predictors of functional limitation were LV end-diastolic dimension (relative risk [RR] 0.63, confidence interval [CI] 0.45 to 0.88; p = 0.008), age (RR 1.09, CI 1.03 to 1.17; p = 0.003), and LV thickness score (RR 1.08, CI 1.02 to 1.13; p = 0.003). LV cavity size was smaller in patients with functional limitation irrespective of obstruction and hypertrophy. Patients with differed from those without a history of syncope for a smaller LV end-diastolic dimension (23.2 +/- 2.5 vs 25.0 +/- 2.7 mm/M2, p = 0.008), which was the only independent predictor of syncope (RR 0.77, CI 0.63 to 0.95; p = 0.013). Thus, a small LV cavity size is associated with functional limitation and history of syncope in HC.

Determinants of efficacy of atrial pacing in preventing atrial fibrillation recurrences

INTRODUCTION

Several studies have shown that single or dual site atrial pacing is effective in reducing the frequency of recurrent atrial fibrillation (AF) in selected patients. However, it is still unclear what the best predictors are of long-term efficacy of atrial pacing.

METHODS AND RESULTS

Forty-seven patients with paroxysmal AF requiring demand pacing underwent electrophysiologic study and dual chamber pacemaker implant. After 4 months of follow-up, patients were divided into two groups according to the presence (group 1) or absence (group 2) of symptomatic AF recurrences. Atrial pacing markedly reduced AF recurrences in all patients. Twenty-four patients were free of arrhythmia. The basal state conduction times (CTs) and the incremental conduction times (ICTs), during programmed electric stimulation between the high right atrium (HRA) and the coronary sinus ostium (CSos), but not between the HRA and the His-bundle region, were significantly longer in group 1. There was no statistical difference in the effective refractory period (ERP) recorded at the HRA, the low right atrium (LRA), and the CSos between the two groups, whereas the differences between the greatest and least recorded ERPs measured from the HRA, LRA, and CSos (deltaERP) were significantly greater in group 1 patients. Two parameters were selected by discriminant multivariate analysis, namely deltaCTos (ICT-CT between HRA and CSos) and deltaERP. The first had a greater relative importance in predicting AF recurrence (r2 = 0.33 and r2 = 0.1, respectively).

CONCLUSION

Single site atrial pacing is effective in reducing AF recurrences, with decreasing efficacy in patients with greater right atrial conduction delay and wider refractoriness dispersion.

Age-related decrease in cardiac tolerance to oxidative stress

Oxygen radical-mediated injury has been implicated in the process of cardiac aging. We investigated the tolerance to oxidative stress of hearts from rats of different age. Langendorff-perfused hearts from 3-12-month-old rats received a 30 min infusion of the reactive oxygen specie hydrogen peroxide (H2O2, 60 microM), followed by a 15 min wash-out. H2O2 infusion resulted in a significantly larger increase in end-diastolic pressure in hearts of 6- and 12-month-old rats than 3 months (P<0.01). In addition, developed pressure and rate-pressure product decreased more evidently in 12-month-old hearts (P<0.01 vs 3 and 6 months). Arrhythmia analysis showed higher score in hearts of 12- and 6-month-old rats with respect to 3-month-old animals (P<0.05). Cardiac release of oxidized glutathione (an index of the ability of the heart to inactivate oxygen metabolites) was significantly lower in hearts from rats of 6 and 12 months than in younger animals (P<0.001). Finally, cardiac concentrations of the scavenger enzymes glutathione peroxidase and Mn-superoxide dismutase also significantly decreased with age. In conclusion, in rat heart metabolic and functional tolerance toward oxidative stress decreases with age. This phenomenon may contribute to the development of cardiovascular alterations with increasing age.

Pathophysiology of heart failure

Heart failure is a leading cause of mortality and morbidity in Western countries. Common etiology is mostly represented by ischemic and hypertensive heart disease. Clinically, heart failure can be defined as an impaired cardiac performance, unable to meet the energy requirements of the periphery. Pathophysiologically, the clinical onset of heart failure symptoms already represents an advanced stage of disease when compensatory mechanisms triggered by the underlying decrease in contractility are no longer capable of maintaining adequate cardiac performance during exercise and, subsequently, under resting conditions. Independent of its underlying etiology, cardiac failure is always characterized by an impairment in the intrinsic contractility of myocytes. As a consequence of reduced contractility, a number of central and peripheral compensatory mechanisms take place that are capable of effectively counteracting reduced intravascular intrinsic performance for a long period of time. Among them, recruitment of preload reserve, enhanced neurohormonal stimulation and cardiac hypertrophy are the most important. All of them, however, also carry unfavorable effects that contribute to further deterioration of cardiac function. In fact, increased end-diastolic volume determines increased wall stress that further reduces systolic performance; sympathetic and angiotensin stimulation increases peripheral resistance and contributes to increase volume expansion; hypertrophic myocytes demonstrate impaired intrinsic contractility and relaxation, and hypertrophy causes a clinically relevant deterioration of ventricular relaxation and compliance that substantially participates in increased end-diastolic pressure, and, therefore, to limited exercise performance. Diastolic dysfunction usually accompanies systolic dysfunction, although in some cases it may represent the prevalent mechanism of congestive heart failure in patients in whom systolic performance is preserved. Biological causes of reduced contractility in heart failure are not completely elucidated. Changes in myosin composition and in sarcoplasmic ATPase activity, causing reduced Ca2+ availability during contraction, have been reported, although their exact contribution is not clear. Recently, impaired endothelial function has also been described in heart failure, and new appealing hypotheses have been made regarding the causative role of circulating cytokines like tumor necrosis factor in the pathogenesis of heart failure.

Feasibility and safety of two French electrode catheters in the performance of electrophysiological studies

The aim of this study was to analyze prospectively the feasibility and safety of using 2 Fr versus 6 Fr standard electrode catheters for diagnostic electrophysiological study.

METHODS

Two hundred and five consecutive patients were randomized to receive the 6 Fr approach (3 quadripolar, 6 Fr, electrode catheters inserted through the left or right femoral vein and placed in the high right atrium, right ventricular apex, and His bundle area) or the 2 Fr approach (3 quadripolar, 2 Fr, electrode catheters inserted through a single, 7 Fr, triple lumen, guiding catheter and positioned at the same sites as the 6 Fr approach).

RESULTS

Introduction time was shorter in the 2 Fr group (133.3 +/- 65 s, range 87-669 s) than in the 6 Fr group (242.8 +/- 91.8 s, range 168-1024 s, P < 0.001). The overall fluoroscopy time was longer in the 2 Fr group (141.2 +/- 40.1 s, range 78-312 s) than in the 6 Fr group (126.4 +/- 39.7 s, range 58-341 s, P = 0.009). However in the last 100 patients there was no more difference between the two groups (137.6 +/- 28.2 s vs 128.4 +/- 23.2 s, P = 0.07). There was no significant difference between 2 Fr and 6 Fr groups in the mean atrial (5.9 +/- 2.2 mV, range 2.2-11.3 mV, vs 6.1 +/- 2.3 mV, range 2.4-12.4 mV, P = 0.57) and ventricular (5.6 +/- 2.1 mV, range 1.9-9.7 mV, vs 5.7 +/- 2.2 mV, range 2.3-10.5 mV, P = 0.66) activation potential amplitudes recorded during sinus rhythm, or in the rate of stable His bundle potential recording (P = 0.3), and catheter dislodgment (P = 0.54). The overall number of complications was significantly higher in the 6 Fr group than in the 2 Fr group (29 vs 5, P = 0.001), as well as the number of entry site related complications (3 vs 12, P = 0.02) and catheter manipulation related complications (2 vs 17, P < 0.001).

CONCLUSIONS

The results of this study show that the use of 2 Fr electrode catheters reduces the rates of entry site and catheter manipulation related complications during EPS. Despite their small size, these catheters allow quick and precise positioning of the electrode.

[The heterogeneity of myocardial sympathetic innervation in normal subjects: an assessment by iodine-123 metaiodobenzylguanidine scintigraphy]

123I-radiolabeled metaiodobenzylguanidine (123I-MIBG) cardiac imaging has been used to evaluate the distribution of sympathetic nervous system (SNS) in the heart. Different heart diseases have shown impaired cardiac SNS distribution as reflected by MIBG activity. The aim of this study was to assess the cardiac distribution of SNS in normal subjects, using MIBG imaging. Ten normal subjects (1 male and 9 females, mean age 46 +/- 9 years) with no cardiac abnormalities underwent myocardial 123I-MIBG scintigraphy, Tc-99m methoxyisobutylisonitrile (MIBI) cardiac perfusion imaging and equilibrium radionuclide angiography (RNA). Regional myocardial MIBG and MIBI activities were quantitatively evaluated using a region of interest analysis. For this purpose, the left ventricle was divided into 6 myocardial regions as anterior, apical, inferior, septum, lateral and posterolateral. In particular, myocardial MIBG and MIBI activities were measured as myocardium to mediastinum ratio. Regional left ventricular function was assessed by RNA. Myocardial MIBG uptake was homogeneous in anterior (2.2 +/- 0.5), inferior (2.5 +/- 0.7), septal (2.4 +/- 0.4), lateral (2.3 +/- 0.4), and posterolateral (2.3 +/- 0.4) regions. Conversely, MIBG uptake was significantly lower in the apical region (1.9 +/- 0.3) compared to all other left ventricular segments (p < 0.05). Regional myocardial perfusion, as measured by MIBI uptake, was homogeneous in all regions. No regional left ventricular wall motion abnormalities were observed by RNA. In conclusion, our data suggest that a decreased MIBG uptake may be observed in the left ventricular apical region of normal subjects reflecting reduced sympathetic innervation of the apex. This finding is not related to myocardial perfusion or wall motion abnormalities. The knowledge of cardiac sympathetic innervation in normal subjects may be helpful to assess SNS abnormalities in heart disease.

Identification of viable myocardium in patients with chronic coronary artery disease using rest-redistribution thallium-201 tomography: optimal image analysis

With the widely used 50% threshold, sensitivity is high, but specificity is low in detecting viable myocardium on 201Tl SPECT. In this study, we sought to identify the best threshold for semiquantitative 201Tl analysis.

METHODS

Rest-redistribution 201Tl SPECT was performed in 46 patients with chronic coronary artery disease before and after myocardial revascularization. Regional function was evaluated by two-dimensional echocardiography before and after myocardial revascularization using a 3-point scale (1 = normal, 2 = hypokinetic, 3 = a/dyskinetic). Myocardial segments with abnormal systolic function were defined as viable if the systolic function score decreased > or = 1 after myocardial revascularization. A second group of 12 patients with chronic coronary artery disease constituted the validation population. Sensitivity-specificity curves, as well as receiver operating characteristic curves, for rest and redistribution mages were generated by varying the 201Tl uptake threshold.

RESULTS

A 65% threshold uptake using resting images was found to be the best for detecting a/dyskinetic segments that improve after myocardial revascularization from those that do not improve. Sensitivity was lower with a 65% threshold (75%) than with a 50% threshold (90%, p < 0.05), but specificity was higher (76% versus 26%, p < 0.05) resulting in better accuracy (76% versus 57%, p < 0.05) and positive predictive value (77% versus 55%), while the negative predictive value was not different (69% versus 75%, p not significant). The area under the receiver operating characteristic curve was significantly (p < 005) larger for rest (0.80 +/- 0.05) as opposed to redistribution (0.72 +/- 0.05) images. Similar results were obtained in a subgroup of patients with low ejection fraction. Significant correlations between the percentage of revascularized viable segments and both the change in ejection fraction and in postrevascularization ejection fraction were found. When these findings were applied in the validation group, a gain in specificity, accuracy and positive predictive value was obtained with the 65% threshold compared with the 50% threshold.

CONCLUSION

This study demonstrated that analysis of resting images and use of the 65% 201Tl uptake threshold is preferable for separating viable from not viable dyssynergic myocardial segments in patients with chronic coronary artery disease.

Effects of vitamin E and HMG-CoA reductase inhibition on cholesteryl ester transfer protein and lecithin-cholesterol acyltransferase in hypercholesterolemia

BACKGROUND

The enzyme lecithin-cholesterol acyl transferase (LCAT) esterifies free cholesterol on high-density lipoprotein (HDL) and the cholesteryl ester transfer protein (CETP) transfers cholesteryl ester to very-low-density lipoprotein (VLDL) and low-density lipoproteins (LDL). Using statins, contradictory findings have been made regarding CETP activity in normolipidemic individuals and in those with familial dysbetalipoproteinemia. In contrast, LCAT activity appears to be unaffected by simvastatin. Antioxidants have also been proposed for the use of anti-atherosclerotic treatment, because the oxidation of LDL may have a key role in the pathophysiology of atherogenesis.

OBJECTIVE

To investigate, in hypercholesterolemic patients, whether a combination of pravastatin with the antioxidant, vitamin E, has greater effects on the activity of CETP and of LCAT than does pravastatin alone.

METHODS

This placebo-diet-controlled multicenter trial included 220 hypercholesterolemic patients who were assigned randomly to groups to receive: diet and 20-40 mg pravastatin (n = 52), diet and alpha-tocopherol (n = 60), or diet associated with placebo (n = 52). Plasma LCAT activity was determined using excess exogenous substrate, containing [3H]cholesterol. Plasma CETP activity was measured in the supernatant fraction after precipitation of endogenous apo B-containing lipoproteins with phosphotungstate-Mg2+. The exchange of cholesteryl esters between [14C]cholesteryl ester-labeled LDL and unlabeled HDL was measured during a 16-h incubation, while LCAT was inhibited.

RESULTS

The addition of pravastatin to the diet induced a significant decrease in plasma CETP activity (P < 0.05); this effect was less evident in the group cotreated with vitamin E. For the first time, it was shown that CETP concentrations increased significantly after vitamin E alone (P < 0.05). No significant differences in the plasma activity of LCAT were observed among the groups.

CONCLUSIONS

Pravastatin reduced CETP activity, but not that of LCAT. Addition of vitamin E prevented the decrease in CETP activity and had no effect on LCAT activity. The mechanism responsible for these effects is unknown, but could involve the prevention of radical-induced damage to CETP by vitamin E.

Pattern of left ventricular filling in hypertrophic cardiomyopathy. Assessment by Doppler echocardiography and radionuclide angiography

AIMS

The left ventricle in hypertrophic cardiomyopathy is anatomically and functionally non-uniform. This study was undertaken to verify whether a heterogeneity in the pattern of diastolic filling can be detected along the left ventricular inflow tract in hypertrophic cardiomyopathy.

METHODS AND RESULTS

Early (E) and late (A) diastolic velocities were recorded by Doppler echocardiography at mitral and at mid-ventricular level in 16 normal volunteers and 30 patients with hypertrophic cardiomyopathy. Patients with hypertrophic cardiomyopathy also underwent radionuclide angiography to assess left ventricular function. E wave decreased significantly in normal volunteers (80 +/- 15 to 60 +/- 14 cm x s(-1); P<0.001), but it increased in hypertrophic cardiomyopathy (76 +/- 22 to 87 +/- 28 cm x s(-1) P=0.04), whereas the A wave decreased similarly in both. By multivariate analysis, systolic asynchrony and the ejection fraction of left ventricular lateral wall were directly related to the pattern of early filling progression (r=0.656, F=9.467; P<0.002). Moreover, systolic asynchrony showed a univariate direct correlation with changes in E velocity (r=0.42; P=0.02).

CONCLUSION

Many patients with hypertrophic cardiomyopathy have an acceleration of filling within the left ventricular inflow tract; this phenomenon is directly related to systolic asynchrony and ejection fraction of the left ventricular lateral wall, suggesting increased suction.

[Effects left ventricle asynchrony on systolic and diastolic function in patients with non-ischemic heart failure]

INTRODUCTION

The asynchrony of the left ventricle--i.e., its nonuniform contraction and relaxation--is an important factor for left ventricular function. Heart failure is often related to abnormal systolic function, sometimes associated with a diastolic dysfunction. We studied the relationship of left ventricular asynchrony to left ventricular function in patients with nonischemic heart failure.

MATERIAL AND METHODS

Radionuclide angiography at rest was performed in 25 patients with nonischemic heart failure and in 26 age and sex matched normal subjects. In addition to ejection fraction and peak filling rate, two indices of left ventricular asynchrony were calculated: the coefficient of variation of regional time to end systole and the coefficient of variation of regional time to peak filling rate. These factors indicate how disperse are the regional values of time to end systole and of time to peak filling rate. In fact, the higher the value, the greater the asynchrony.

RESULTS

A significant (r = .46, p < .05) inverse correlation was found between the ejection fraction and the coefficient of variation of regional time to end systole in both the normal subjects and the heart failure patients, while the ejection fraction correlated significantly (r = .46, p < .05) with the coefficient of variation of regional time to peak filling rate only in the patients. Moreover, the peak filling rate was inversely correlated (r = .57, p < .05) with the coefficient of variation of regional time to peak filling rate in the heart failure patients but not in the normal subjects.

CONCLUSIONS

These results suggest that left ventricular systolic and diastolic asynchrony may contribute to impair left ventricular systolic and diastolic function in patients with nonischemic heart failure.

Combined evaluation of rest-redistribution thallium-201 tomography and low-dose dobutamine echocardiography enhances the identification of viable myocardium in patients with chronic coronary artery disease

The purpose of this study was to evaluate whether combined evaluation by discriminant analysis of rest-redistribution thallium-201 tomography and low-dose dobutamine echocardiography enhances the accuracy in identifying viable myocardium in patients with chronic coronary artery disease. Rest-redistribution 201Tl has high sensitivity but low specificity in identifying viable myocardium, while the opposite is true for low-dose dobutamine echocardiography. Forty-six patients underwent low-dose dobutamine echocardiography and rest-redistribution 201Tl tomography on the same day. Rest echocardiography was repeated at least 30 days (mean 40+/-20) after myocardial revascularization. Discriminant analysis was applied to the results of 201Tl tomography and dobutamine echocardiography to classify a/dyskinetic segments as viable or non-viable. In 92 a/dyskinetic segments that were revascularized, rest-redistribution 201Tl tomography yielded an accuracy of 75%, while the accuracy of dobutamine echocardiography was 70% (P<0.05). When discriminant analysis was used, the combined evaluation gave an accuracy of 83% (P<0.05 vs both tests). These findings demonstrate that low-dose dobutamine echocardiography and 201Tl imaging are useful and complementary techniques for identifying viable myocardium in patients with chronic coronary artery disease. Combined evaluation by discriminant analysis significantly improves accuracy, although the cost-effectiveness of such an approach remains to be determined.

Genetic mapping of the mouse Rab7 gene and pseudogene and of the human RAB7 homolog

Rab proteins are small GTP-ases localized to distinct membrane compartments in eukaryotic cells and regulating specific steps of intracellular vesicular membrane traffic. The Rab7 protein is localized to the late endosomal compartment and controls late steps of endocytosis. We have isolated, by library screening, the 5' region, including the promoter, of the mouse Rab7 gene and a Rab7 pseudogene. We have mapped, by genetic linkage analysis, the mouse Rab7 gene on Chromosome (Chr) 6 and the Rab7-ps1 pseudogene on Chr 9, where the Rab7 gene has been previously reported to map. By radiation hybrid mapping, we have located the human RAB7 gene on Chr 3, in a region homologous to the mouse Chr 6, where the Rab7 gene maps.

Signalling of the Ret receptor tyrosine kinase through the c-Jun NH2-terminal protein kinases (JNKS): evidence for a divergence of the ERKs and JNKs pathways induced by Ret

The RET proto-oncogene encodes a functional receptor tyrosine kinase (Ret) for the Glial cell line Derived Neurotrophic Factor (GDNF). RET is involved in several neoplastic and non-neoplastic human diseases. Oncogenic activation of RET is detected in human papillary thyroid tumours and in multiple endocrine neoplasia type 2 syndromes. Inactivating mutations of RET have been associated to the congenital megacolon, i.e. Hirschprung's disease. In order to identify pathways that are relevant for Ret signalling to the nucleus, we have investigated its ability to induce the c-Jun NH2-terminal protein kinases (JNK). Here we show that triggering the endogenous Ret, expressed in PC12 cells, induces JNK activity; moreover, Ret is able to activate JNK either when transiently transfected in COS-1 cells or when stably expressed in NIH3T3 fibroblasts or in PC Cl 3 epithelial thyroid cells. JNK activation is dependent on the Ret kinase function, as a kinase-deficient RET mutant, associated with Hirschsprung's disease, fails to activate JNK. The pathway leading to the activation of JNK by RET is clearly divergent from that leading to the activation of ERK: substitution of the tyrosine 1062 of Ret, the Shc binding site, for phenylalanine abrogates ERK but not JNK activation. Experiments conducted with dominant negative mutants or with negative regulators demonstrate that JNK activation by Ret is mediated by Rho/Rac related small GTPases and, particularly, by Cdc42.

Effects of myocardial revascularization on regional thallium-201 uptake and systolic function in regions with reverse redistribution on tomographic thallium-201 imaging at rest in patients with chronic coronary artery disease

OBJECTIVES

There is growing evidence that myocardial segments with reverse redistribution are viable in patients with chronic coronary artery disease. The aim of this study was to assess the effects of myocardial revascularization on systolic function and thallium-201 uptake in such segments.

METHODS

Rest-redistribution thallium-201 tomography before and after myocardial revascularization was performed in 47 patients with chronic coronary artery disease. Regional function was evaluated by two-dimensional echocardiography before and after revascularization according to a 3-point scale (1 = normal, 2 = hypokinetic, 3 = a/dyskinetic). Improvement of dysfunctional segments was defined when systolic function score decreased > or =1 after revascularization. Reverse redistribution was defined as >8% decrease in relative thallium-201 uptake between rest and redistribution images.

RESULTS

Reverse redistribution was found in 27 (57%) of 47 patients, corresponding to 60 (11%) of 564 myocardial segments. Of such segments, 24 (40%) had normal systolic function, 19 (32%) were hypokinetic, and 17 (28%) were a/dyskinetic. Thirty-six segments underwent myocardial revascularization, and reverse redistribution was no longer present in 86% of them subsequent to the procedure. Of 26 dyssynergic segments with reverse redistribution subjected to revascularization, 18 (69%) improved at follow-up.

CONCLUSIONS

The findings of the present study indicate that reverse redistribution is a reversible phenomenon and is often associated with improvement of systolic function following revascularization in patients with chronic coronary artery disease.

[Early detection of heart involvement using serial cardiologic controls in the follow-up of patients with AIDS]

New effective therapies have been producing longer survival times for HIV-patients. Thus non-infectious complications of late stage of HIV infection (such as the development of left ventricular dysfunction) have emerged; in fact cardiac involvement has been identified frequently at autopsy and is described in 80% of patients with acquired immunodeficiency syndrome (AIDS) as an evidence of the virus cardiotrophism, while clinical findings of left ventricular dysfunction were only detected in about 15% of the patients. It is possible that the development of heart failure had been underestimated in those years; in fact signs and symptoms of cardiac involvement had been often misinterpreted as the results of non cardiac causes (pulmonary failure or infections) also determining a delay in the beginning of cardiac therapy. The aim of this study was to follow 16 human immunodeficiency-virus positive patients during a 3-year period to evaluate the usefulness of early detection of heart failure in order to start a specific therapy as soon as possible. The follow-up consisted of a clinical and electrocardiographic control every 4 months. Echocardiography was carried out when involvement of the cardiac muscle was suspected. During the follow-up we could reveal an early involvement in 5/16 patients (31.2%) and in 2 of them (40%) early therapy caused clinical and echocardiographic regression of left ventricular dysfunction. The present study demonstrates that periodical clinical and echocardiographic controls are useful in patients with HIV infection.

New-onset angina preceding acute myocardial infarction is associated with improved contractile recovery after thrombolysis

BACKGROUND

Ischaemic preconditioning reduces myocardial infarct size in animal models. Clinical data suggest that episodes of angina immediately before acute myocardial infarction may be associated with smaller infarct size in man. However, it is unclear whether ischaemic episodes preceding acute myocardial infarction also affect contractile recovery in patients.

OBJECTIVE

In this study we investigated the recovery of regional myocardial function after thrombolysis in two groups of patients at their first Q-wave acute myocardial infarction; in one group (n = 42) myocardial infarction occurred unheralded, whereas patients of the second group (n = 48) had experienced new-onset angina in the 48 h that preceded infarction. Echocardiographic analysis of myocardial regional function in the infarct area was done at 2, 24 and 72 h after thrombolysis, and at 1 week, and 1 and 3 months follow-up.

RESULTS

Peak level of MB-creatine kinase was significantly lower in patients with new-onset angina (96 +/- 47 as compared with 221 +/- 108 IU.l-1, P < 0.01), as was the area under the MB-creatine kinase curve (1321 +/- 876 as compared to 3879 +/- 1555 U.l-1/36 h, P < 0.01). Hypokinetic segments were fewer in patients with pre-infarction angina. Similarly, wall motion score improved significantly earlier in patients who had new-onset angina before acute myocardial infarction. Thus, contractile recovery was more rapid in patients with previous angina than in those in whom infarction occurred unheralded. Complications during the in-hospital outcome and other variables considered during the 4-week follow-up were similar between groups.

CONCLUSIONS

Patients who experienced new-onset angina before acute myocardial infarction showed better recovery of regional function after thrombolysis. Our study supports the hypothesis that brief periods of ischaemia immediately before myocardial infarction may precondition the human heart, thus improving contractile recovery.

Noninvasive evaluation of left ventricular diastolic function in hypertrophic cardiomyopathy

Diastolic dysfunction is common in hypertrophic cardiomyopathy (HC). Previous studies suggest that Doppler transmitral flow velocity profiles, and the left atrial (LA) M-mode echogram can be used noninvasively to evaluate left ventricular (LV) diastolic function. However, this has not been proved in HC. In this study we determined the relation of Doppler transmitral flow velocity profiles and the LA M-mode echograms to invasive indexes of LV diastolic function in patients with HC. We studied 25 patients with HC, while off drugs, and calculated LA global and active fractional shortening and the slope of both early and late displacement of the posterior aortic wall during LA emptying by M-mode echocardiography. We calculated peak velocity of early (E) and atrial (A) filling, E to A ratio, and E-wave deceleration time by pulsed Doppler echocardiography, and simultaneous radionuclide angiography, LV pressures, time constant of isovolumic relaxation tau, and the constant of chamber stiffness k by cardiac catheterization. The time constant of isovolumic relaxation tau correlated with the slope of early posterior aortic wall displacement (r = 0.59; p <0.01). LV end-diastolic pressure correlated with global LA fractional shortening (r = -0.75; p <0.001); the constant of chamber stiffness k correlated with active LA fractional shortening (r = -0.53; p <0.02). In a subset of 13 patients, in whom echocardiography and cardiac catheterization were performed simultaneously, similar results were found. LA M-mode recordings provide a more reliable noninvasive assessment of diastolic function in HC than mitral Doppler indexes.

A short burst of oxygen radicals at reflow induces sustained release of oxidized glutathione from postischemic hearts

Oxygen radical generation induced by postischemic reperfusion can overwhelm endogenous radical scavenging systems, resulting in "oxidative stress." Release of oxidized glutathione (GSSG) upon reflow has been taken as evidence for the occurrence of oxidative stress in postischemic hearts. However, demonstration that GSSG release is due to oxygen radicals and not to other consequences of ischemia/reperfusion is lacking. To address this issue, isolated rabbit hearts underwent 30 min of global ischemia at 37 degrees C. At reflow, control hearts were perfused with standard buffer for 45 min (n = 8); treated hearts received the oxygen radical scavenger superoxide dismutase (hSOD) for 15 min, followed by 30 min of standard perfusion (n = 8). During reperfusion control hearts showed a prominent release of GSSG, which peaked 5 min after reflow. Interestingly, GSSG release was still significantly elevated 45 min into reperfusion, at a time when oxygen radical generation has long ceased. In contrast, in hSOD-treated hearts GSSG release was negligible. Prevention of oxidative stress was also associated with significantly greater recovery of function. Thus, GSSG release occurs in postischemic hearts as a direct consequence of oxygen radical generation, and it may outlast the initial oxidant load.

Antithrombotic effects of recombinant human, active site-blocked factor VIIa in a rabbit model of recurrent arterial thrombosis

The extrinsic coagulation pathway is activated when circulating factor VII (FVII) gains access to tissue factor (TF) exposed as a consequence of vascular injury. Increasing evidence indicates that this TF-dependent activation of the coagulation plays an important role in the pathophysiology of intravascular thrombus formation. In the present study, we tested the effects of recombinant human, active site-blocked activated FVII (FVIIai) in a rabbit model of carotid artery thrombosis. Cyclic flow variations (CFVs), due to recurrent thrombus formation, were obtained in stenotic rabbit carotid arteries with endothelial injury. Carotid blood flow velocity was measured by a Doppler flow probe. After 30 minutes of CFVs, the animals received FVIIai (100 microg x kg(-1) x min(-1) intracarotid infusion for 10 minutes, n=9). If CFVs were abolished, animals were followed for 30 additional minutes, after which recombinant human activated FVII (FVIIa) was infused into the carotid artery (100 microg x kg(-1) x min(-1) for 10 minutes) to determine whether FVIIai could be displaced from TF by FVIIa, thus restoring CFVs. To establish the duration of action of FVIIai, an additional group of animals received FVIIai at the same dose as above, and after CFVs were inhibited, they were followed until CFVs were restored or for up to 6 hours. To determine whether CFVs could be restored by epinephrine after their abolition with FVIIai, increasing doses of epinephrine were administered to a third group of 6 animals. FVIIai abolished CFVs in 8 of 9 rabbits (P<.01). This effect was reversible, as FVIIa administration restored CFVs in all animals. Prothrombin times and activated partial thromboplastin times did not change significantly throughout the study. One single 10-minute infusion exerted complete antithrombotic effects for at least 6 hours, despite the fact that at this time point, plasma FVIIai levels were well below threshold concentrations. Epinephrine restored CFVs in 3 of 6 animals in which CFVs were inhibited by FVIIai. FVIIai exerts potent antithrombotic effects in this model; these effects were prolonged even after FVIIai was almost completely cleared from the circulation, probably as a result of the tight binding of FVIIai to TF. Thus, FVIIai might represent an antithrombotic substance of potential interest.

In vivo gene transfer: prevention of neointima formation by inhibition of mitogen-activated protein kinase kinase

BACKGROUND

The mitogen-activated protein kinase kinase (MAPKK) is a protein downstream ras which is rapidly activated in cells stimulated with various extracellular signals. These proteins are believed to play a pivotal role in integrating and transmitting transmembrane signals required for cell growth.

METHODS AND RESULTS

To study the effect of inhibition of MAPKK on smooth muscle cell (SMC) proliferation in vivo after vascular injury, we performed experimental balloon angioplasty using the standard Clowes technique in male Wistar rats 14-weeks old. The animals did not receive any treatment after vascular injury (N = 6) or were randomly assigned to receive, after balloon injury, a 30% (w/v) pluronic gel solution applied to the injured carotid artery, containing respectively: 1) no plasmid DNA (n = 10); 2) RSV-lacZ (encoding the beta-galactosidase gene) as control gene without effects on SMC proliferation (n = 10); 3) Tg-CAT (encoding cloramphenicol acetyl-transferase gene under the control of thyreoglobulin promoter) as an additional control gene without effects on SMC proliferation (n = 7): 4) a negative mutant of Mitogen-Activated Protein Kinase Kinase (MAPKK-) (n = 13). Fourteen days after vascular injury, carotid arteries were removed and cross sections were cut and stained with hematoxylin/eosin. Morphometric analysis demonstrated, in the MAPKK- treated rats, a significant reduction of both neointima (0.096+/-.018 mm2 vs. 0.184+/-0.019 mm2, p < 0.01) and neointima/media ratio (0.603+/-0.103 vs. 1.471+/-0.161, p < 0.01) compared to control DNA.

CONCLUSIONS

The inhibition of MAPKK, by a dominant inhibitor mutant gene, prevents the SMC proliferation after vascular injury in vivo.

Ceruloplasmin impairs endothelium-dependent relaxation of rabbit aorta

This study evaluated the effects of ceruloplasmin, the copper-containing blue oxidase of vertebrate plasma, on the relaxation of rabbit aortic rings after endothelial release of nitric oxide (NO). Ceruloplasmin at physiological, i.e., micromolar, concentrations inhibited relaxation of rabbit aorta induced by endothelium-dependent agonists like acetylcholine or ADP, whereas it was ineffective toward vasodilation due to direct stimulation of smooth muscle cells by nitroglycerin. The effect was reversible and specific for native, fully metalated ceruloplasmin, since relaxation was not impaired by the heat-treated or metal-depleted derivatives. A trapping mechanism, involving a direct interaction of NO or other NO-containing species (like nitrosothiols and iron-dinitrosyls) with the copper sites and/or with the free thiol of ceruloplasmin, could be safely excluded on the basis of spectroscopic and chemical analyses of the protein exposed to authentic NO, nitrosothiols, or iron-dinitrosyls. The data presented in this paper constitute the first evidence of impairment of the endothelium-dependent vasodilatation by a plasma protein and may shed some light on the still uncertain physiological role of ceruloplasmin.

Occurrence of the same peroxidative compounds in low density lipoprotein and in atherosclerotic lesions from a homozygous familial hypercholesterolemic patient: a case report

Oxidative modification of low density lipoprotein (LDL) and its byproducts may play a fundamental role in atherosclerosis. We report an in vitro analysis of LDL peroxidative compounds in an homozygous familial hypercholesterolemic (HFH) patient who subsequently died. During the autopsy, we analyzed lipids extracted directly from different atherosclerotic plaques, and we also provided an immunocytochemical analysis using the specific monoclonal antibody MDA2 (directed against malondialdeyde-lysine epitopes of oxidized LDL). The results showed that the same species of peroxidative compounds were present both in LDL in vitro and in lipids extracted directly from atherosclerotic lesions. Moreover, the immunocytochemistry analysis revealed a positive staining of atherosclerotic plaques, confirming the presence of LDL oxidation-specific epitopes. Although observation of a single case is necessarily limited, our findings are consistent with the hypothesis that oxidative modification of LDL is involved in human atherogenesis.

Effects of high-cholesterol and atherogenic diets on vascular relaxation in spontaneously hypertensive rats

Hypercholesterolemia is associated with more rapid development of atherosclerosis, and hypertension is frequently associated with abnormal vascular function. Therefore, to investigate the role of hypercholesterolemia and hypertension on vascular function, we studied three groups of male rats (aged 6 wk): normotensive Wistar-Kyoto rats (WKY) as a control group and spontaneously hypertensive rats (SHR) receiving either standard diet (SD; SHR-SD) or high-cholesterol (1%) diet (ChD; SHR-ChD). Vascular reactivity was tested on isolated aortic rings at 4 wk and at 3 and 6 mo of diet. At 3 mo, endothelium-dependent relaxation to acetylcholine (ACh) and ADP was significantly reduced in SHR-ChD but not in SHR-SD compared with WKY. At 6 mo, relaxations to ACh were further impaired in both SHR groups compared with WKY. Endothelium-independent vasodilation to nitroglycerin (NTG) was not different in the three groups of animals throughout 6 mo of diet. In additional experiments, we evaluated vascular reactivity in rats fed with ChD enriched with an excess of vitamin D [atherogenic diet (AD)] capable of producing vascular atherosclerotic lesions. In particular, we studied three additional groups of WKY and SHR rats fed with SD, AD, or AD plus a nonhypotensive dose of the calcium antagonist nitrendipine (Nit). Vasodilation to ACh and ADP was significantly blunted in WKY-AD compared with WKY-SD, whereas it was partially improved in WKY-Nit. There were no differences in endothelium-independent relaxation to NTG in the three WKY groups. In contrast, SHR-AD showed a marked reduction of endothelium-dependent and -independent vasodilation, but only endothelium-dependent vasodilation was preserved by addition of Nit to the diet. These data suggest that the development of vascular dysfunction in rat genetic hypertension is accelerated by ChD, in absence of detectable vascular lesions. Our study also shows that AD alters both vascular smooth muscle and endothelium-dependent relaxation. Low doses of Nit partially preserve endothelium-dependent vasodilation but do not affect the impairment of smooth muscle function in these rats.

Heart rate variability in patients with hypertrophic cardiomyopathy: association with clinical and echocardiographic features

Autonomic dysfunction has been reported in patients with hypertrophic cardiomyopathy. To evaluate the influence of different clinical and echocardiographic features of the disease on sympathovagal balance, as assessed by heart rate variability, 33 patients with hypertrophic cardiomyopathy and 33 healthy volunteers underwent echocardiographic examination and 24-hour electrocardiogram Holter recording. Measures of vagal modulation of heart rate were lower in patients with hypertrophic cardiomyopathy than in controls, particularly in those exhibiting syncope, exertional chest pain, dyspnea, or moderate or severe mitral regurgitation. Furthermore, the age-corrected multiple regression analysis showed that the parasympathetic cardiac control was inversely related to left atrial dimension and directly related to left ventricular end-systolic dimension. Therefore in hypertrophic cardiomyopathy the parasympathetic withdrawal is more evident in patients with symptoms than in those without; the reduction in left ventricular end-systolic dimension and the increase in left atrial size are the echocardiographic features that most influence the sympathovagal balance.

Laparoscopic inguinal hernioplasty: a community hospital's experience

Although controversial, laparoscopic inguinal hernia repair has become increasingly popular among surgeons. The overall advantages of this procedure over conventional hernia repair have not as yet been substantiated. One hundred and three consecutive laparoscopic, transabdominal, preperitoneal inguinal hernia repairs in 91 patients were evaluated retrospectively. Patients' satisfaction was assessed using the Visick grading system. The mean follow-up was 18.3 months. One case was converted to an open procedure. Eighty-eight patients (91%) were discharged on the day of surgery. Eighty-seven patients (96%) were satisfied with the operation (Visick grades I & II). Twenty-nine patients who previously underwent a traditional open herniorraphy stated that they would have preferred the laparoscopic method if they had the choice. Early complications included wound infection (n = 1), urinary retention (n = 1) and intestinal obstruction necessitating a laparotomy (n = 1). All patients were ambulating without significant pain after a mean of 7.6 days, and returned to work after 2.4 weeks on average. There was one case of recurrence. In conclusion, patients are satisfied with the laparoscopic hernioplasty technique, which is associated with a low morbidity and short term recurrence rate. Laparoscopic hernioplasty should be considered a viable and valuable alternative to the open method. It appears especially attractive for recurrent or bilateral hernias.

Activation of cAMP-PKA signaling in vivo inhibits smooth muscle cell proliferation induced by vascular injury

Injury of the arterial wall induces the formation of the neointima. This structure is generated by the growth of mitogenically activated smooth muscle cells of the arterial wall. The molecular mechanism underlying the formation of the neointima involves deregulated cell growth, primarily triggered by the injury of the arterial wall. The activated gene products transmitting the injury-induced mitogenic stimuli have been identified and inhibited by several means: transdominant negative expression vectors, antisense oligodeoxynucleotides, adenovirus-mediated gene transfer, antibodies and inactivating drugs. Results of our study show that local administration of 3',5'-cyclic AMP and phosphodiesterase-inhibitor drugs (aminophylline and amrinone) to rats markedly inhibits neointima formation after balloon injury in vivo and in smooth muscle cells in vitro. The growth inhibitory effect of aminophylline was completely reversed by the inhibition of cAMP-dependent protein kinase A (PKA). These findings indicate an alternative approach to the treatment of diseases associated with injury-induced cell growth of the arterial wall, as stimulation of cAMP signaling is pharmacologically feasible in the clinical setting.

[Evaluation of left ventricular function in patients with mammary carcinoma after treatment with epidoxorubicin using a high-dose, short-term protocol]

Anthracyclines are effective chemotherapeutic agents against various malignancies but their therapeutic value is limited by well-known dose-related cardiotoxicity, mainly induced by oxygen free radicals. Left ventricular diastolic and systolic functional abnormalities precede the clinical evidence of cardiotoxicity. The aim of this study was to evaluate the possible cardiotoxicity of epidoxorubicin administered as "high-dose short-term" protocol. Twenty patients (mean age 50.4 +/- 7.9 years) without cardiac disease, affected by advanced breast cancer were studied. All patients were treated with epidoxorubicin as neoadjuvant chemotherapy according to the new protocol "high-dose short-term" (cumulative dose 475.8 +/- 35.6 mg/m2, range 450-600 mg/m2, in 4-6 weeks). The effectiveness of cancer chemotherapy was monitored by clinical evaluation and mammography performed before and after treatment. All patients underwent color Doppler echocardiography and resting radionuclide angiocardiography in baseline condition and 30 +/- 10 days after the last cycle of chemotherapy. All patients showed a significant reduction of tumor lesion after chemotherapy. Left ventricular systolic and diastolic function parameters obtained by echocardiography (fractional shortening 33.1 +/- 4.5% vs 32.4 +/- 4.8%; ejection fraction 63.6 +/- 6.2% vs 62.9 +/- 5.7%; E/A ratio 1.73 +/- 0.64 vs 1.82 +/- 0.67; E wave deceleration time 204 +/- 24.6 ms vs 208.5 +/- 31.7 ms;isovolumetric relaxation time 79 +/- 15.7 ms vs 80 +/- 17.8 ms) and radionuclide angiocardiography (ejection fraction 62.4 +/- 7% vs 61.8 +/- 5.9; peak ejection rate 2.87 +/- 0.44 VTD/s vs 2.74 +/- 0.46 VTD/s; peak filling rate 2.72 +/- 0.54 VTD/s vs 2.6 +/- 0.58 VTD/s) did not show significant changes after treatment. In conclusion, our results suggest that epidoxorubicin administration using the "high-dose short-term" protocol in patients with breast cancer does not induce early significant abnormalities of left ventricular systolic and diastolic function.