The usefulness of carvedilol and nebivolol in preventing contrast nephropathy in rats.

BACKGROUND: Oxidative stress and vasoconstriction appear to be important components of contrast nephropathy (CN) pathogenesis, and both carvedilol and nebivolol are known to have vasodilatory and antioxidant effects. AIMS: This study aimed to investigate whether carvedilol and nebivolol play preventive roles against developing CN and to compare the effects of each. MATERIALS AND METHODS: Wistar albino rats were divided into control (C, n = 6), contrast material (CM, n = 6), carvedilol (CV, n = 7), carvedilol + contrast material (CV + CM, n = 7), nebivolol (N, n = 7), and nebivolol + contrast (N + CM, n = 7) groups. Following 3 days of dehydration, 6 mL/kg diatrizoate was administered to each rat. Carvedilol was given at a dose of 2 mg/kg and nebivolol at a dose of 1 mg/kg by way of oral gavage. After scarification, total antioxidant capacity (TAC), malondialdehyde (MDA), and superoxide dismutase (SOD) were studied in renal tissue. Histopathological findings were graded as mild (+), moderate (++), and severe (+++). RESULTS AND DISCUSSION: Most of the histopathological findings and MDA levels were significantly higher in the CM group than that in the C, CVCM, and NVCM groups, whereas there was no significant difference between the C, CVCM and NVCM groups. TAC level in the CM group was significantly lower than in all other groups. There was no difference in SOD among groups. CONCLUSIONS: Carvedilol and nebivolol both prevent development of nephropathy related to CMs by decreasing oxidative stress. Neither is superior to the other.

The first histopathological evidence of trimetazidine for the prevention of contrast-induced nephropathy.

AIM: We aimed to investigate the prophylactic effects of trimetazidine (TMZ) against contrast-induced nephropathy (CIN) in rat kidneys. METHODS AND RESULTS: 28 Wistar rats were divided into 4 groups of 7 rats each (control (C), contrast media (CM) TMZ, trimetazidin+contrast media groups (TMZ + CM). The administration of TMZ solution was done on d2, d3 and d4. Fifth day, contrast media was administered at a single dose. On d6 scarification was performed. The oxidant/antioxidant parameters were measured and histopathological scores were performed in kidney tissues. Most of the histopathological scores were significantly higher in the CM group as compared to other groups. Moreover, the scores of the TMZ + CM and C groups were not statistically different. CM group, had significantly higher levels of MDA compared to the C and CM + TMZ groups (562.82 ± 38.15 vs. 419.15 ± 49.01 and 507.34 ± 14.16 01 nmol/mg protein respectively) (p<0.001). CM group had significantly lower levels of SOD as compared to C, CM + TMZ and TMZ groups (p<0.05). CONCLUSION: To the best of our knowledge, this study for the first time, histopathologically demonstrated the effectiveness of TMZ for the prevention of CIN.

The effect of L-carnitine on oxidative stress responses of experimental contrast-induced nephropathy in rats.

This study was conducted to investigate the prophylactic effects of carnitine against contrast-induced nephropathy (CIN) and its relation to oxidant/antioxidant status in kidney, liver, heart, spleen and lung tissues in a CIN rat model. Twenty-eight adult male Wistar rats were divided into 4 groups, the control, contrast media (CM), carnitine and contrast media+carnitine (CM+carnitine) groups. Animals were placed in individual metabolism cages, and on the 2nd day, rats were deprived of water for 24 hr. On the 3rd day, contrast media were administered to groups CM and CM+carnitine. L-carnitine was administered on days 2, 3 and 4. Histopathological changes were evaluated in the right kidney after euthanization. Superoxide dismutase (SOD) and catalase (CAT) activities and glutathione (GSH) and malondialdehyde (MDA) levels were measured in renal, liver, heart, spleen and lung tissues. The SOD activities in the renal (P<0.05), liver (P<0.001) and spleen (P<0.05) tissues were increased in the carnitine group. The CAT activities in the spleen tissue were decreased (P<0.01) only in the CM group. Renal (P<0.05), liver (P<0.001), spleen (P<0.001) and lung tissue (P<0.01) GSH levels were found to be higher in the carnitine group. In renal, liver and lung tissues, the MDA levels increased in the CM group (P<0.001). The histopathological findings showed that L-carnitine may have a preventative effect in alleviating the negative effects of CIN. Similar to this, L-carnitine may play a major role in the stability of the antioxidant status in the kidney, liver, spleen and lung of the CIN rat model.

Dipyridamole stress echocardiography and ultrasonic myocardial tissue characterization in predicting myocardial ischemia, in comparison with dipyridamole stress Tc-99m MIBI SPECT myocardial imaging.

The purpose of this study was to validate whether dipyridamole stress ultrasonic tissue characterization with cyclic variation of integrated backscatter (CVIBS) compared with dipyridamole stress echocardiography and dipyridamole stress Tc99m-MIBI SPECT myocardial perfusion scintigraphy could predict myocardial ischemia in patients with chronic coronary artery disease. Twenty patients (16 M, 4 F) who had coronary angiography for stable angina pectoris were included in the study. Mean age was 62 +/- 8 years. The left ventricle was divided into 16 segments. Regional wall motion analysis and CVIBS measurements were obtained from 16 myocardial segments at rest and after dipyridamole (0.84 mg/kg) infusion. After 10 minutes, Tc-99m MIBI (10 mCi) was injected and SPECT myocardial imaging was performed. After 3 hours, 25 mCi Tc-99m MIBI was reinjected and rest images were obtained. A total of 320 ventricular wall segments were evaluated. Two hundred and six ventricular wall segments were supplied by stenotic coronary arteries and 114 segments were supplied by normal coronary arteries. Dipyridamole stress Tc-99m MIBI SPECT studies showed abnormal myocardial perfusion in 176 segments and normal perfusion in 144 segments. Transient regional wall motion abnormality was detected in 116 segments. A significant decrease in CVIBS after dipyridamole stress was detected in 184 segments. The sensitivity and specificity of dipyridamole stress echocardiography, Tc-99m MIBI SPECT, and CVIBS were 56% and 100%, 85% and 92%, and 89% and 100%, respectively, compared with the results from coronary angiography. Dipyridamole stress ultrasonic tissue characterization with CVIBS may provide more sensitive detection of myocardial ischemia than dipyridamole stress echocardiography and may be as valuable as dipyridamole stress myocardial perfusion scintigraphy.

A new echocardiographic method for the assessment of the severity of aortic regurgitation: color M-mode flow propagation velocity.

PURPOSE: Echocardiographic Doppler methods widely used in assessment of the severity of aortic regurgitation (AR) are considered sensitive and reliable. However, they all have limitations for quantitation of AR. The color M-mode Doppler flow propagation velocity (FPV) method has been shown to provide useful insights in the evaluation of left ventricular diastolic function and appears to be minimally affected with preload changes. Clinical data regarding the value of FPV in the determination of the significance of valvular insuffiencies are lacking. The purpose of this study was to evaluate the use of FPV in measurement of the severity of AR and to compare its reliability with angiography and other echocardiographic methods. METHODS: Twenty-nine patients (13 male, 16 female) who had cardiac catheterization for various reasons before echocardiographic evaluation were included. The mean age was 53.6 +/- 13.4 years. At the time of cardiac catheterization, the degree of AR was assessed as mild in 10 patients, as moderate in 12, and as severe in 7. In all patients, FPV measurements of AR were obtained with color M-mode Doppler in the apical 5-chamber view. Regurgitation jet height and its ratio to left ventricular outflow obtained in the parasternal long axis with color flow Doppler, pressure half-time, and slope of AR obtained with continuous wave Doppler in apical 5-chamber view were other echocardiographic methods chosen for comparison. RESULTS: The mean values of FPV were 93.1 +/- 18.4 cm/s, 49.8 +/- 8.0 cm/s, and 31.7 +/- 4.9 cm/s in severe, moderate, and mild AR groups, respectively (P <.001). Significant correlation was observed between angiographic grades, FPV, pressure half-time, slope, and jet height and ratio to left ventricular outflow (P <.0001, r = 0.93; P <.0001, r = -0.81; P <.0001, r = 0.76; P <.0001, r = 0.92, respectively). CONCLUSION: FPV is a simple, practical, and reliable method for the quantification of AR.

Transthoracic echocardiographic documentation of disappearance of massive pulmonary artery thromboemboli after fibrinolytic therapy.

In this paper, we report two cases of acute massive pulmonary thromboemboli with pulmonary artery thrombus, in which disappearance of thrombus followed fibrinolytic therapy were documented at transthoracic echocardiographic follow-up. Data from these limited experiences suggest that, transthoracic echocardiography might be useful as a first diagnostic screening in cases of suspect pulmonary thromboembolism and thrombolytic therapy might be considered in patients with pulmonary artery thrombus with pulmonary embolism.