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Biomedical subjects

A Biggi

Publications and source records attributed to A Biggi.

At least 37 records · Page 2Linked to original sources
PubMed1990

[A study of the variations in myocardial perfusion induced by systemic thrombolysis in acute myocardial infarct using sequential scintigraphy with 201-thallium].

To assess scintigraphic changes induced by intravenous streptokinase therapy, serial rest redistribution thallium-201 perfusion imaging was performed in 62 patients with acute myocardial infarction lasting less than 6 hours. Twenty-seven patients randomized to treatment with intravenous streptokinase (group A) and 35 to conventional therapy (group B) underwent thallium-201 scintigraphy as soon as possible after admission to the coronary care unit (early study). Regional myocardial perfusion was assessed using thallium-201 scintigraphy 7-9 days later in each patient (late study). The size of the perfusion defect was evaluated using a semi-quantitative score. The size of the perfusion defect decreased in serial scans in both group A (preintervention score: 12.1 +/- 6.8; redistribution score: 11.4 +/- 6.8; late study: 8.8 +/- 7.0) and group B (12.8 +/- 6.5; 12.3 +/- 6.7; 10.6 +/- 7.5, respectively). No statistical difference in myocardial perfusion was found between the two groups, on late study. Peak serum creatine kinase MB (CKMB) was earlier in group A than in group B (1030.8 +/- 326.6 vs 1361.0 +/- 271.1: p less than 0.001). The fast CKMB release group (onset of symptoms-peak of CKBM less than or equal to 900 minutes) exhibited higher thallium-201 uptake when compared to the slow CKMB release group, at the time of late study (perfusion defect score: 6.1 +/- 5.7 vs 10.7 +/- 7.3: p = 0.03). Reversibility was observed in 21/62 patients (34%). Reversibility corresponded to unchanged or improved perfusion defect score on late study in 18/21 patients (86%). Nevertheless 20/41 (49%) patients not showing redistribution of thallium-201 within pre-treatment defect had an improvement in regional perfusion on late study. Reversibility was observed in 9/14 (64%) patients with fast CKMB release and in 12/47 (26%) patients with slow CKMB release. We conclude that the early peak of CKMB is associated with a higher uptake of thallium-201 on late study. Furthermore, the reversibility of perfusion defect on redistribution imaging forecasts evolution of scintigraphic perfusion, but, when this is not present, it doesn't rule out late improvement of thallium-201 myocardial uptake. The low sensitivity and specificity of redistribution imaging and the procedure related delay in instituting therapy make thallium-201 scintigraphy unreliable in the evaluation of myocardial reperfusion following thrombolysis.

Adult↗
PubMed1990

[Acute cholecystitis. Early diagnostic study using cholescintigraphy with Tc99m-IDA].

34 patients admitted for suspected acute cholecystitis were evaluated using 99mTc IDA cholescintigraphy. The results of these studies are reviewed and compared with other diagnostic tests and the subsequent clinical diagnosis. Cholescintigraphy proved to be a safe, simple, highly accurate and sensitive technique. Therefore, 99mTc-IDA cholescintigraphy is proposed as the initial procedure of choice in the evaluation of patients with suspected acute cholecystitis.

Acute Disease↗
PubMed1989

[A clinical case of severe megaloblastic anemia during treatment with primidone].

The case of a patient who developed megaloblastic anemia caused by folate deficiency during treatment with primidone is reported. The serum level of folic acid was significantly low. Two causes able to produce folate deficiency have been discovered: chronic assumption of primidone, and low dietary intake of folic acid. The anemia was completely reversed by oral supplementation of folic acid. It has already been recognized that additional nutritional deficiency is required to precipitate a frank megaloblastic anemia during therapy with antiepileptic drugs.

Administration, Oral↗
PubMed1988

Role of renal hemodynamics in the exaggerated natriuresis of essential hypertension.

Extracellular fluid volume expansion is known to produce exaggerated natriuresis in essential hypertension. In order to assess the role of hemodynamic and intrarenal physical factors upon natriuretic response to central volume expansion, two hour water immersion (WI) experiments were made in six uncomplicated essential hypertensives and six normotensive healthy controls. Before and during WI we measured mean arterial pressure (MAP), urine flow (V/min), sodium (UNaV) and potassium (UKV) excretion, glomerular filtration rate (GFR), effective renal plasma flow (ERPF) and intrarenal (wedged) venous pressure (IRVP). In comparison with normotensive controls, the exaggerated natriuretic response in hypertensives (P less than 0.05 for UNaV during WI) was associated with an enhanced vasodilating response as demonstrated by a greater increase in ERPF (P less than 0.05) and by a more pronounced fall in calculated renal precapillary resistances (P less than 0.05). A more significant increase in IRVP was found in hypertensive group (P less than 0.05). Glomerular filtration rate (GFR) did not change in either group during WI. MAP, unchanged in normotensives, was significantly reduced in hypertensives (P less than 0.05), while remaining in the hypertensive range. These findings suggest that intrarenal physical factors play a major role in determining the exaggerated natriuresis during WI in hypertensive man.

Adult↗
PubMed1988

Circulating opioid peptides during water immersion in normal man.

1. This study was designed to evaluate variations in plasma beta-endorphin, methionine-enkephalin, adrenocorticotropic hormone and serum prolactin in healthy volunteers during head-out water immersion. 2. Water immersion induced an increase in methionine-enkephalin plasma levels, which was associated with a significant fall in mean arterial pressure and heart rate. 3. Conversely, a suppression of plasma beta-endorphin, adrenocorticotropic hormone and serum prolactin was detected during water immersion. 4. We suggest that a dopaminergic inhibitory control mechanism may be involved in regulating circulating levels of beta-endorphin, adrenocorticotropic hormone and prolactin in normal subjects undergoing extracellular fluid volume expansion produced by water immersion.

Adrenocorticotropic Hormone↗
PubMed1987

Dopamine blockade abolishes the exaggerated natriuresis of essential hypertension.

We studied natriuresis during central hypervolaemia by immersing eight normal subjects and eight patients with uncomplicated essential hypertension up to the neck in water, either in the absence (study 1) or presence (study 2) of dopamine blockade by metoclopramide. Water immersion without metoclopramide induced an exaggerated natriuresis in hypertensives compared with normotensives (P less than 0.001). This occurred in the presence of identical hormonal (plasma renin activity, plasma aldosterone and prolactin), renal (creatinine clearance) and pressor responses in both groups (study 1). The marked natriuresis seen during water immersion alone in normotensives was significantly blunted (P less than 0.02) but not abolished during water immersion with addition of metoclopramide. On the other hand, the exaggerated natriuresis found in hypertensives during water immersion alone was completely abolished during water immersion plus dopamine blockade by metoclopramide (study 2). Similar hormonal, renal and pressor changes were detected in both normotensive and hypertensive subjects during water immersion plus metoclopramide administration. Our data demonstrate that metoclopramide abolishes the exaggerated natriuretic response seen in hypertensives during volume expansion produced by water immersion, and suggest that dopamine may play a critical role in mediating the hypernatriuresis of essential hypertension.

Adult↗
PubMed1986

Renal hemodynamics and natriuresis during water immersion in normal humans.

The renal vascular and functional responses to acute "central hypervolemia" by water immersion to the neck were determined in six normal subjects. During isotonic-isooncotic expansion by water immersion there was a significant increase in urine flow from 1.1 +/- 0.1 to 6.9 +/- 1.0 ml/min (p less than 0.05) and sodium excretion from 99.1 +/- 8.8 to 300 +/- 28 mu Eq/min (p less than 0.05). Glomerular filtration rate did not change while renal blood flow significantly increased during water immersion. Deep intrarenal venous pressure (IRVP) increased from 18.2 +/- 1.4 to 32 +/- 1.7 mmHg (p less than 0.05) while mean arterial pressure was unchanged. This marked natriuresis seen during water immersion was associated with reduced renal vascular resistance and increased deep intrarenal venous pressure demonstrating that continued natriuresis could relate to increased capillary hydrostatic pressure.

Adult↗
PubMed1986

Dopamine blockade and natriuresis during water immersion in normal man.

Natriuresis was studied during water immersion in eight normal subjects either in the absence or in the presence of dopamine blockade by domperidone. Creatinine clearance showed no significant changes; urine flow remained significantly above control values during water immersion, implying persistent suppression of antidiuretic hormone. The marked natriuresis seen during water immersion alone was significantly blunted (P less than 0.05) but not abolished during water immersion plus domperidone. Suppression of the renin-aldosterone system by water immersion alone was not significantly different from that obtained during water immersion plus dopamine blockade. On the contrary, plasma prolactin levels, previously suppressed during water immersion alone, were significantly stimulated during water immersion plus domperidone, thus indirectly suggesting a role of dopamine in mediating the blunted natriuresis seen during water immersion.

Adult↗
PubMed1985

Cardiovascular, baroreflex and humoral responses in hypertensive patients during nicardipine therapy.

Cardiovascular, baroreflex and humoral responses were evaluated in 8 patients with essential hypertension during a control period and then after oral treatment for 5 days with nicardipine hydrochloride 60 mg/d, a calcium channel antagonist. Systolic, diastolic and mean arterial cuff pressures fell after the treatment from 145.7, 98.6 and 114 mmHg control to 136.5, 86.1 and 102.9 mmHg. Heart rate increased from 71 to 78.7 beats/min indicating activation of the baroreflex control mechanism. Neurally mediated changes in the cardiovascular responses to an increase in carotid baroceptor activity and to dynamic exercise were not affected by the drug, nor was the renin-aldosterone system. Thus, a clinically dose of nicardipine significantly reduced mean arterial pressure, whilst preserving circulatory homeostasis.

Adult↗
PubMed1985

Renin-aldosterone system suppression during water immersion in renovascular hypertension.

We studied renin-aldosterone system behaviour in five renovascular hypertensive patients during central hypervolaemia by water immersion to the neck. Water immersion significantly suppressed the high peripheral renin levels of the patients despite an autonomic renin secretion from the stenotic kidney, a significant reduction of mean blood pressure and an increase in distal tubule sodium concentration. The effect of immersion on plasma aldosterone appeared to be primarily mediated via suppression of plasma renin activity (PRA). Our data suggest that: (a) the renin secretion is mainly modulated by cardiopulmonary receptors activity; (b) the neurogenic reflex control of plasma renin activity is very effective in renovascular hypertension.

Adult↗
PubMed1985

Low-pressure receptor activity and exaggerated natriuresis in essential hypertension.

Urinary sodium excretion, central hemodynamics, and mean arterial pressure (MAP) were studied in 7 normal subjects and 19 hypertensive patients during both central hypervolemia by water immersion to the neck (NI) and extracellular volume expansion by i.v. saline infusion. During 2-hour NI, 12 out of the 19 hypertensives exhibited a significant fall in MAP (p less than 0.001). Exaggerated natriuresis did not occur in these patients (ns). In the remaining 7 hypertensive patients in whom, during NI, MAP was unchanged, exaggerated natriuresis was found (p less than 0.001). During saline infusion, MAP was either unchanged or increased and exaggerated natriuresis was found in all hypertensive patients (p less than 0.001) previously submitted to NI. Our findings suggest that a high MAP is a major determinant of exaggerated natriuresis in arterial hypertension.

Adolescent↗
PubMed1984

[Contribution of computerized radioisotope angiocardiography to the diagnosis of arrhythmogenic dysplasia of the right ventricle].

Radionuclide angiography phase analysis was performed in two patients presenting with recurrent right-sided ventricular tachycardia without angiographic evidence of valvular or ischemic heart disease. A dilated, poorly contracting (EF = 20%) right ventricle with localized dyskinetic areas was found in contrast with normal left ventricular function. The suggested diagnosis of Arrhythmogenic Right Ventricular Dysplasia was confirmed by right ventricular angiography performed in one patient. The diagnostic interest of radionuclide angiography phase analysis in patients with Arrhythmogenic Right Ventricular Dysplasia is stressed.

Adult↗
PubMed1982

Comparison of calculated and measured free thyroid hormones in serum in health and in abnormal states.

To evaluate a theoretical model for calculating free thyroid hormones, based on the law of mass action, we compared values for both calculated and measured free thyroxin and free triiodothyronine in a group of normal subjects. To determine whether the concentrations of circulating free hormones were also predictable from equilibrium considerations in abnormal states, we compared calculated and measured free thyroid hormone values in an additional population including pregnant women and hyperthyroid, hypothyroid, and "sick euthyroid" patients. Predictions based on the model were accurate in all these states except pregnancy, where there was some discrepancy between calculated and measured values for both hormones. In pregnant women with large abnormalities in thyroid-hormone-binding proteins, euthyroidism was accompanied by significantly lower free hormone concentrations, leading us to conclude that, in pregnancy, equilibrium may be reached at concentrations lower than those in other healthy subjects. Values for calculated and measured free thyroid hormones in "sick euthyroids" showed no discrepancy; however, we cannot exclude the possibility that non-dialyzable compounds are present that interfere with the hormone-protein binding.

Adult↗
PubMed1982

[Effects of passive semiorthostatic cardiopulmonary hematic centralization (by immersion in water) on hydrosaline elimination and on the renin-angiotensin-aldosterone system in essential hypertension].

In 25 patients with essential hypertension and 9 control subjects we have studied the effects of central hypervolemia during water immersion on both renin-angiotensin-aldosterone system and renal function (diuresis volume and urine excretion of Na, k and osmoles). Reduction of blood pressure, plasma renin activity and aldosterone was found to be similar in both groups; renal excretion of water, Na, K and osmoles was significantly higher in the hypertensive group compared to the controls. These urinary features may be related to a reduced proximal tubular reabsorption by cardiorenal reflex due to cardiopulmonary volume receptors stimulation without any change of GFR measured as the creatinine clearance. The urinary pattern, observed during water immersion in hypertensive group without any change of plasma sodium, osmolality or protein concentration, was comparable to "exaggerated natriuresis"; this may suggest that also "exaggerated natriuresis" is due either to renal vasodilatation or to renal tubular sympathetic activity reduction secondary to a cardiorenal reflex by cardiopulmonary volume expansion.

Adolescent↗