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A Nappi

Publications and source records attributed to A Nappi.

At least 55 records · Page 3Linked to original sources
PubMed1991

[Morpho-functional evaluation of hypertensive patients with renal artery stenosis. Correlations between angiography and dynamic scintigraphy].

Renovascular hypertension is the most important and common cause of secondary hypertension. We studied 10 patients with arterial hypertension and different degrees of renal artery stenosis to assess the usefulness of dynamic radionuclide renography in evaluating renal perfusion and function, and to compare functional radionuclide results to the morphological findings of renal angiography. Computer-assisted dynamic renal imaging with 99mTc diethylenetriaminepentaacetic acid (DTPA) and 131I ortho-iodohippurate (OIH), and renal arteriography were also employed in all patients. In all patients, radionuclide results matched angiographic findings in quality. In particular, 3 patients with hemodynamically insignificant renal artery stenosis exhibited normal perfusion and function at dynamic radionuclide renography. Seven patients had significant renal artery stenosis and associated functional changes at dynamic radionuclide renography. Quantitative comparison of all patients showed a significant correlation (r = 0.866, p less than 0.001) between the degree of renal artery stenosis, quantified as the percentage of narrowing as compared to adjacent/contralateral normal vessel diameter, and the results of split renal function, as assessed during OIH studies and expressed per kidney as a percentage of the net total counts of both kidneys. In conclusion, our results demonstrated dynamic radionuclide renography to be a valuable tool in the assessment of functional changes secondary to renal artery stenosis in hypertensive patients, providing complementary results to arteriography.

Adolescent↗
PubMed1983

Increased methyl esterification of membrane proteins in aged red-blood cells. Preferential esterification of ankyrin and band-4.1 cytoskeletal proteins.

The enzymatic carboxyl methyl esterification of erythrocyte membrane proteins has been investigated in three different age-related fractions of human erythrocytes. When erythrocytes of different mean age, separated by density gradient centrifugation, were incubated under physiological conditions (pH 7.4, 37 degrees C) in the presence of L-[methyl-3H]methionine, the precursor in vivo of the methyl donor S-adenosylmethionine, a fourfold increase in membrane-protein carboxyl methylation was observed in the oldest cells compared with the youngest ones. The identification of methylated species, based on comigration of radioactivity with proteins stained with Coomassie blue, analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis, shows, in all cell fractions, a pattern similar to that reported for unfractionated erythrocytes. However in the membrane of the oldest erythrocytes the increase in methylation of the cytoskeletal proteins, bands 2.1 and 4.1, appears to be significantly more marked compared with that observed in the other methylated polypeptides. Furthermore the turnover rate of incorporated [3H]methyl groups in the membrane proteins of the oldest cells markedly increases during cell ageing. Particularly in band 4.1 the age-related increase in methyl esterification is accompanied by a significant reduction of the half-life of methyl esters. The activity of cytoplasmic protein methylase II does not change during cell ageing, while the isolated ghosts from erythrocytes of different age show an age-related increased ability to act as methyl-accepting substrates, when incubated in presence of purified protein methylase II and methyl-labelled S-adenosylmethionine, therefore the relevance of membrane structure in determining membrane protein methylation levels can be postulated. Finally the possible correlation of this posttranslational protein modification with erythrocyte ageing is discussed.

Adult↗
PubMedDate not supplied

Left ventricular dysfunction in coronary artery disease: comparison between rest-redistribution thallium 201 and resting technetium 99m methoxyisobutyl isonitrile cardiac imaging.

BACKGROUND: We compared rest-redistribution thallium 201 and resting technetium 99m methoxyisobutyl isonitrile (MIBI) cardiac imaging in 29 men with angiographically proven coronary artery disease and regional ventricular dysfunction. Left ventricular ejection fraction at radionuclide angiography was 35% +/- 9%. METHODS AND RESULTS: Regional left ventricular wall motion was assessed on gated 99mTc MIBI images according to a 3-point scale (0 = normal, 1 = hypokinetic, 2 = akinetic or dyskinetic). 201Tl and 99mTc MIBI uptake values were analyzed quantitatively. A total of 435 myocardial segments were classified on the basis of wall motion analysis into three groups: group 1 (normal wall motion; n = 201), group 2 (hypokinetic; n = 132), and group 3 (akinetic or dyskinetic; n = 102). 201Tl and 99mTc MIBI uptake values were significantly higher in groups 1 and 2 compared with group 3 (p < 0.05) and in group 1 compared with group 2 (p < 0.05). When 201Tl and 99mTc MIBI uptake values were directly compared, no significant differences in group 1 and 2 were observed. In group 3, 99mTc MIBI uptake (67% +/- 14%) was significantly lower (p < 0.001) than initial (72% +/- 11%) and delayed 201Tl uptake (73% +/- 12%). CONCLUSION: Thus rest-redistribution 201Tl and resting 99mTc MIBI cardiac imaging reflect the severity of left ventricular dysfunction in coronary artery disease. However, in segments with severely impaired regional ventricular function, 201Tl uptake is significantly higher than 99mTc MIBI uptake.

Adult↗
PubMedDate not supplied

Adenosine coronary vasodilation quantitative technetium 99m methoxy isobutyl isonitrile myocardial tomography in the identification and localization of coronary artery disease.

BACKGROUND: Exercise and dipyridamole 99mTc-labeled methoxy isobutyl isonitrile (MIBI) myocardial scintigraphy have been widely used for the diagnosis of coronary artery disease (CAD). However, only limited data on adenosine 99mTc-labeled MIBI cardiac imaging are currently available. This study was designed to assess the accuracy of quantitative adenosine-rest 99mTc-labeled MIBI tomography in the diagnosis and localization of CAD. METHODS AND RESULTS: Fifty-seven consecutive patients with suspected CAD who underwent coronary angiography and 22 normal volunteers were studied. All patients underwent 99mTc-labeled MIBI tomography after administration of adenosine (140 micrograms/kg intravenously for 6 minutes) and at rest. A total of 171 vascular coronary territories were analyzed quantitatively. All patients with CAD (> or = 50% luminal stenosis) (n = 55) had abnormal 99mTc-labeled MIBI tomograms. The normalcy rate was 86% by quantitative analysis. Overall sensitivity, specificity, and diagnostic accuracy for detection of individual stenosed vessels were 84%, 87%, and 85%, respectively. In patients with one-vessel CAD (n = 24), sensitivity and diagnostic accuracy in the detection of individual stenosed vessels were significantly (p < 0.05) higher compared with patients with multivessel CAD (n = 31). Moreover, 75% of patients with one-vessel disease showed a scintigraphic pattern characterized by the presence of perfusion defects in only one coronary artery territory, and 74% of patients with multivessel disease showed a scintigraphic pattern characterized by the presence of perfusion defects in two or more coronary artery territories. Sensitivity, specificity, and diagnostic accuracy for detecting individual diseased vessels were similar in patients without previous myocardial infarction (n = 18) compared with those with previous myocardial infarction (n = 39). In myocardial territories related to noninfarcted areas (n = 124), sensitivity and specificity in the detection of stenosed vessels were 75% and 88%. In infarcted areas (n = 47), sensitivity and specificity in the detection of stenosed vessels were 98% and 80% (differences not significant vs noninfarcted areas). CONCLUSIONS: Adenosine-controlled coronary vasodilation combined with quantitative 99mTc-labeled MIBI tomography is accurate for identifying patients with CAD and localizing individual stenosed coronary arteries.

Adenosine↗
PubMedDate not supplied

Technetium 99m-labeled tetrofosmin myocardial tomography in patients with coronary artery disease: comparison between adenosine and dynamic exercise stress testing.

BACKGROUND: Pharmacologic coronary vasodilation with adenosine, combined with myocardial scintigraphy, is a useful test for the diagnosis of coronary artery disease (CAD) in patients unable to exercise. It has been demonstrated recently that exercise 99mTc-labeled tetrofosmin cardiac imaging can be used for the detection of CAD. However, no data are available comparing 99mTc-labeled tetrofosmin adenosine and exercise tests in the same patients. METHODS AND RESULTS: The results of adenosine and exercise 99mTc-labeled tetrofosmin myocardial tomography were compared in 41 patients (37 men and four women; mean age 53 +/- 8 years) with suspected or known CAD who underwent coronary angiography. All patients were submitted, on separate days, to three injections of 99mTc-labeled tetrofosmin (740 MBq intravenously): one at rest, one during bicycle exercise, and one during adenosine infusion (140 micrograms/kg/min for 6 minutes with injection of 99mTc-labeled tetrofosmin at 4 minutes). A total of 902 myocardial segments were analyzed quantitatively. One patient had normal coronary vessels, 19 patients had single-vessel CAD, 12 patients had two-vessel CAD, and nine patients had three-vessel CAD (> 50% coronary stenosis) on coronary angiography. Adenosine induced a significant increase in heart rate (88 +/- 16 beats/min at peak vs 72 +/- 11 beats/min at rest; p < 0.01). Systolic and diastolic blood pressure was not significantly different after adenosine infusion compared with rest. Double product was 22931 +/- 7039 at peak exercise and 11229 +/- 3413 after adenosine (p < 0.01). Agreement on the presence of abnormal single-photon emission computed tomography by adenosine and exercise was 100% by quantitative analysis. In all segments a significant relationship between exercise and adenosine 99mTc-99m-labeled tetrofosmin uptake was observed (r = 0.90; p < 0.001). Segmental agreement for regional 99mTc-labeled tetrofosmin uptake score between exercise and adenosine was observed in 737 (82%) of the 902 segments (kappa value of 0.66). Concordance between the two studies for identification of perfusion status was observed in 809 (90%) of the segments (kappa value of 0.80). Sensitivity and specificity for detection of stenosed vessels were not different for dynamic exercise stress testing and adenosine 99mTc-labeled tetrofosmin cardiac tomography. CONCLUSIONS: Despite different hemodynamic effects, adenosine and dynamic exercise 99mTc-labeled tetrofosmin single-photon emission computed tomographic imaging provides similar information in the diagnosis and localization of CAD.

Adenosine↗
PubMedDate not supplied

[Ambulatory monitoring of left ventricular function with a radionuclide detector system].

The recent development of new radionuclide detectors allows noninvasive outpatient monitoring of left ventricular function. This study was aimed at describing a new radionuclide technique useful to monitor cardiac function and at evaluating its potential clinical applications. We studied 14 normal subjects, 30 patients with coronary artery disease and 25 patients with dilated cardiomyopathy. Left ventricular function was continuously monitored in control conditions at rest, during daily physical activity of different intensity (walking on a level surface and climbing stairs), and during bicycle exercise. Left ventricular ejection fraction (EF) variability during recording in control conditions at rest was 0.2 +/- 1.8%. A significant relationship between outpatient EF at rest and conventional equilibrium radionuclide angiography was observed (r = 0.97, n = 69, p less than 0.001). In normal subjects both daily physical activity and exercise stress test induced an increase in heart rate and EF. In patients with coronary artery disease and in patients with dilated cardiomyopathy a heterogeneous EF response was observed during physical activity and exercise stress test. Our results demonstrate that this technique can be used for the ambulatory monitoring of left ventricular function in both normal subjects and patients with different types of cardiomyopathies.

Adult↗