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At least 145 records · Page 8Linked to original sources
PubMed1993

Human small cell lung cancer cell lines express functional atrial natriuretic peptide receptors.

Small cell lung cancer cell (SCLC) lines, NCI-H82, NCI-H660, and NCI-H1284, and HeLa cells were analyzed for the presence of atrial natriuretic peptide (ANP) receptors. In these SCLC cell lines and HeLa cells, ANP A receptor mRNA was identified by Southern blot analyses of polymerase chain reaction products and RNase protection assays using poly(A)(+)-selected RNA. Saturable binding assays revealed that HeLa cells had 2000 to 5000 high affinity atrial natriuretic peptide receptors per cell with a dissociation constant of 140 pM. In the SCLC cell lines, the binding was saturable but too low to accurately estimate the number of binding sites. After addition of human ANP, radioimmunoassays revealed accumulation of cyclic GMP in SCLC cells as well as HeLa cells in a dose-dependent fashion. The half-maximal stimulation concentration of cyclic GMP accumulation in HeLa and these SCLC cell lines was approximately 2 nM. Tetrazolyl blue assays and tritiated thymidine incorporation did not show any remarkable growth inhibition or growth stimulation of SCLC cell lines after addition of human ANP up to 3.3 microM, more than 1000-fold greater than the half-maximal stimulation concentration of cyclic GMP accumulation. Our results indicate that human SCLC cells express functional ANP receptors but ANP addition produced no detectable change in their growth pattern.

Atrial Natriuretic Factor↗
PubMed1976

Functionally atrialized parchment-like right ventricle with extensive myocardial fibrosis of left ventricle.

A 18-year-old female with unusual type of parchment-like right ventricle died of intractable congestive heart failure was reported. A catheter study revealed the absence of systolic contraction of the right ventricle. The pressure tracing curve in the right ventricle was virtually the same as in the right atrium. At autopsy, there was an extensive myocardial fibrosis of the left ventricle in addition to the almost total absence of the myocardium of the right ventricle. The case was considered to be a unique type of idiopathic cardiomyopathy.

Adolescent↗
PubMed1991

Effects of hyperglycaemia on kidney function, atrial natriuretic factor and plasma renin in patients with insulin-dependent diabetes mellitus.

In normoalbuminuric patients with insulin-dependent diabetes mellitus, plasma atrial natriuretic factor (ANF), cyclic GMP and active renin and the renal clearances of [99Tcm]-diethylenetriaminepentaacetic acid (DTPA) lithium and sodium were studied on a hyperglycaemia day and a euglycaemia day. Baseline euglycaemia was achieved by an overnight variable insulin infusion, which during study days was fixed at the rate necessary to maintain euglycaemia in the morning. After a baseline euglycaemic clearance period of 90 min, measurements were repeated in a new 90-min period beginning 150 min later. On the hyperglycaemia day i.v. infusion of 20% glucose was started at the end of the euglycaemic baseline period, increasing blood glucose (5.3 +/- 1.3 vs 12.1 +/- 1.2 mmol l-1, p less than 0.01). On the euglycaemia day blood glucose declined (5.1 +/- 1.0 vs 4.2 +/- 1.0 mmol l-1, p less than 0.02). Glomerular filtration rate (GFR) was unchanged by acute hyperglycaemia (127 +/- 16 vs 129 +/- 24 ml min-1, NS), but nearly normalized during maintained euglycaemia on the euglycaemia day (124 +/- 17 vs 105 +/- 16 ml min-1, p less than 0.01). When comparing the hyperglycaemic study period with the similarly timed period on the euglycaemia day, GFR was elevated by hyperglycaemia (129 +/- 24 vs 105 +/- 16 ml min-1, p less than 0.01), while the renal clearances of lithium and sodium were similar. Consequently, the calculated absolute proximal reabsorption rate of sodium and water was elevated during hyperglycaemia. Hyperglycaemia reduced the slight decline in plasma concentrations of ANF and cyclic GMP observed on the euglycaemia day. Active renin, glucagon and plasma osmolality were unchanged. In conclusion, marked changes in glomerular filtration rate are induced by changes in blood glucose concentration, but the effect is delayed and thus not directly related to renal tubular transport of glucose. Hyperglycaemia does not affect renal clearances of lithium and sodium, while proximal tubular reabsorption is markedly stimulated. These changes are not related to changes in ANF, renin, glucagon or plasma osmolality.

Adult↗
PubMed1989

Functional atrial natriuretic peptide receptor in human adrenal tumor.

The effects of synthetic human atrial natriuretic peptide (ANP) on the release of catecholamines, aldosterone, or cortisol were observed in human adrenal tumors obtained surgically from patients with pheochromocytoma, primary aldosteronism, or Cushing's syndrome, respectively. Each tumor tissue or adjacent normal cortical tissue was sectioned into slices, which were incubated in medium-199 in the presence or absence of adrenocorticotrophin (ACTH) and ANP. The amounts of epinephrine, norepinephrine, aldosterone, or cortisol released into the medium were measured. Existence of ANP receptors on the adrenal tissues was examined by binding assays, affinity labeling, and immunohistochemistry. Release of catecholamines from pheochromocytoma tissues was inhibited by ANP, and the presence of the ANP receptor on pheochromocytoma was further demonstrated by both binding assays and affinity labeling; Scatchard analysis revealed a single class of binding sites for ANP with a Kd of 1.0 nM and a Bmax of 0.4 pmol/mg of protein and the molecular size was estimated as 140 and a 70 kDa under nonreducing and reducing conditions, respectively. The presence of ANP receptors in pheochromocytoma was demonstrated by immunohistochemistry. ANP inhibited both basal and ACTH-stimulated aldosterone secretion in the slices of normal cortex, and localization of ANP receptors in zona glomerulosa cells was also demonstrated. However, ANP did not inhibit basal and ACTH-stimulated aldosterone and cortisol secretion in both tissue slices from aldosteronoma and Cushing's adenoma. Consistent with these observations, the absence of ANP receptors in adenoma tissues was determined by binding assays, affinity labeling, and immunohistochemistry.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex↗
PubMed1997

Clinical variables affecting recovery of left atrial mechanical function after cardioversion from atrial fibrillation.

OBJECTIVES: We sought to evaluate the effect of clinical factors on recovery of atrial function after cardioversion for atrial fibrillation. BACKGROUND: Lack of effective mechanical atrial function (EMAF) after cardioversion of atrial fibrillation predisposes to thromboembolic complications and delays improvement in functional capacity. METHODS: Fifty-two patients underwent cardioversion (group I, electrical cardioversion, n = 40; group II, pharmacologic or spontaneous cardioversion, n = 12) for atrial fibrillation. Serial transmitral inflow Doppler variables were recorded after cardioversion until EMAF (atrial filling velocity > 0.50 m/s) was seen. Clinical variables (age, duration of atrial fibrillation, left ventricular ejection fraction, left atrial diameter, underlying cardiovascular disease, antiarrhythmic drug therapy and mode of cardioversion) were tested for an association with the outcomes of recovery of atrial function by day 3 and day 7. RESULTS: Effective mechanical atrial function recovered in 68% of patients by day 3 and in 76% by day 7 after cardioversion. The mode of cardioversion was significantly associated with recovery of atrial function by day 3 in bivariate and multivariate analyses (odds ratio 0.12, 95% confidence interval 0.01 to 1.0, for electrical cardioversion). None of the variables had an association with recovery of atrial function by day 7. Group I patients took a longer time to recover atrial function than group II patients (p = 0.012). In addition, group I patients had a significantly lower peak atrial filling velocity (mean [+/-SD] 0.39 +/- 0.19 m/s vs. 0.56 +/- 0.16 m/s) and a higher early filling to atrial filling velocity ratio (2.5 +/- 1.2 vs. 1.5 +/- 0.5) after cardioversion. CONCLUSIONS: A high proportion of patients recover EMAF within 1 week after cardioversion. Patients who undergo electrical cardioversion display a greater degree and a longer duration of mechanical atrial dysfunction than those who convert pharmacologically or spontaneously.

Age Factors↗
PubMed1998

Assessment of left atrial appendage function after cardioversion of atrial fibrillation: relation to left atrial mechanical function.

Although several flow patterns in the left atrial appendage have been described, mechanical determinants of its function have not been elucidated in human beings. We attempted to investigate changes in left atrial appendage function after cardioversion of atrial fibrillation and examine the potential relation between appendage function and left atrial mechanical function. Twenty patients without mitral valvular disease underwent transesophageal and transthoracic echocardiography at 24 hours and 1 week after cardioversion of atrial fibrillation. Left atrial appendage function was assessed by the pulsed Doppler measurements of left atrial appendage emptying and filling velocities corresponding to early and late ventricular diastole, respectively. Left atrial mechanical function was evaluated by the transmitral A-wave velocity, percent atrial contribution of the total left ventricular filling (percent atrial filling), and the pulmonary venous A-wave velocity. Left ventricular function was also estimated with conventional M-mode echocardiography. The late appendage emptying and filling velocities markedly increased during 1 week after cardioversion (p < 0.0001, respectively). This finding was associated with an increase in left atrial mechanical function. Changes in the late emptying and filling velocities significantly correlated with changes in the transmitral A-wave velocity (r = 0.59, p < 0.01), percent atrial filling (r = 0.61, p < 0.005), and the pulmonary venous A-wave velocity (r = 0.56, p < 0.05). In contrast, little change was observed in the early emptying and filling velocities. There was no relation between the indexes of left ventricular function and those of appendage function. In conclusion, unless there was an alteration of the loading conditions, left atrial appendage function improved over several days after cardioversion, and its function was related to left atrial mechanical function.

Adult↗
PubMed1995

Clinical significance of fibrillatory wave amplitude. A clue to left atrial appendage function in nonrheumatic atrial fibrillation.

Seventy-eight patients with chronic nonrheumatic atrial fibrillation were studied by transesophageal echocardiography with regard to the left atrial appendage function and its relation to the coarseness of atrial fibrillation on electrocardiogram. These 78 patients (52 men and 26 women; mean age, 66 +/- 10 years; range, 40 to 94 years) were classified into two groups according to the presence of coarse (group 1, n = 46; those with the greatest amplitude of fibrillatory wave in lead V1 > or = 1 mm) or fine (group 2, n = 32; those without the coarse fibrillatory wave in lead V1) atrial fibrillation on a standard 12-lead electrocardiogram within 1 month of echocardiographic studies. There were no significant differences in age, sex, mean duration of atrial fibrillation, left ventricular end-diastolic dimension, left ventricular end-systolic dimension, left ventricular ejection fraction, and left atrial dimension between the two groups. In group 1, however, the left atrial appendage ejection fraction (24.4 +/- 14.2% vs 32.6 +/- 14.8%; p < 0.05) and the peak emptying velocity (21.7 +/- 12.6 cm/s vs 30.4 +/- 14.3 cm/s; p < 0.01) were lower than those in group 2. There were higher incidences of left atrial appendage spontaneous echo contrast (26/46 vs 7/32; p < 0.005) and thrombus (8/46 vs 0/32; p < 0.05) in group 1 patients. The coarse atrial fibrillation revealed a sensitivity of 80.0%, a specificity of 58.1%, a positive predictive value of 60.9%, and a negative predictive value of 78.1% for the presence of left atrial appendage spontaneous echo contrast and/or thrombus formation. In conclusion, in patients with coarse nonrheumatic atrial fibrillation, the left atrial appendage function is usually poor and the incidence of spontaneous echo contrast and thrombus formation appears to be higher in these patients.

Adult↗
PubMed1990

Comparative values of the precordial and transesophageal approaches in the echocardiographic evaluation of atrial baffle function after an atrial correction procedure.

Previous methods used to assess atrial baffle function after correction of transposition of the great arteries have included precordial echocardiography and cardiac catheterization. To evaluate whether single plane transesophageal echocardiography might provide additional information, its findings were correlated with information derived from both precordial echocardiography and cardiac catheterization in 15 patients (14 Mustard procedures, 1 Senning procedure) aged 4.2 to 33 years (mean 16.3). Precordial ultrasound with combined imaging, color flow mapping and pulsed Doppler ultrasound visualized the supramitral portion of the common systemic venous atrium in every case but could identify only superior limb obstruction in three of six patients, mid-baffle obstruction in zero of two and inferior limb obstruction in zero of two patients. Transesophageal studies with use of the same range of ultrasound methods demonstrated superior limb obstruction (severe in four, mild in two) in six of six patients, mid-baffle obstruction in two of two and inferior limb obstruction in two of two patients. The entire pulmonary venous atrium was equally well interrogated by either ultrasound approach, with both identifying three cases (two mild, one moderate) of mid-pulmonary venous atrium obstruction. However, individual pulmonary vein velocity profiles could only be recorded by transesophageal pulsed Doppler ultrasound. Precordial studies identified baffle leaks (1 large, 2 small) in only three patients, whereas transesophageal studies identified 11 such baffle leaks (1 large, 10 small), which were multiple in two patients. It is concluded that transesophageal echocardiography provides a more detailed and accurate assessment of atrial baffle morphology and function than is provided by either precordial ultrasound or cardiac catheterization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2003

Relationship between left atrial appendage function and left atrial thrombus in patients with nonvalvular chronic atrial fibrillation and atrial flutter.

The relationship between the left atrial appendage (LAA) function, as assessed by transesophageal echocardiography, and the incidence of left atrial thrombus was evaluated in 62 patients with nonvalvular chronic atrial fibrillation (AF; n=50) and atrial flutter (AFL; n=12). It was hypothesized that in both AF and AFL not only the LAA flow velocity (LAAFV), but also the frequency of the LAA movement (the LAA flow time, LAAFT) is a major contributing factor to thrombus formation. LAAFT was defined as the average duration of LAA flow with emptying and filling waves. The patients with AF were divided into 2 groups: lone AF (n=14) and non-lone AF (n=36). LAA thrombus was found in 6 patients with none-lone AF. LAAFV was lower and LAAFT was shorter in patients with thrombus as compared with patients without thrombus (12.0+/-2.2 cm/s vs 24.1+/-10.6 cm/s, 68.7+/-1.5 ms vs 72.9+/-3.3 ms, p<0.01, respectively). Patients with AFL had higher LAAFV and longer LAAFT than those with chronic AF. The present data suggest that, in addition to LAAFV, LAAFT characterized LAA function and might serve as a predictor of thrombus formation in chronic AF. With respect to LAA function, patients with lone AF or AFL are at low risk for thrombus formation.

Aged↗