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Biomedical subjects

F Spinelli

Publications and source records attributed to F Spinelli.

At least 37 records · Page 2Linked to original sources
PubMed1993

Myocardial blood flow distribution in patients with ischemic heart disease or dilated cardiomyopathy undergoing heart transplantation.

BACKGROUND: The present investigation was designed to obtain an absolute measurement of myocardial blood flow and of its transmural distribution in ischemic heart disease and idiopathic dilated cardiomyopathy and to provide a reference standard for cardiac imaging in nuclear cardiology. METHODS AND RESULTS: Regional myocardial blood flow and its transmural distribution were estimated by the reference microsphere method in eight patients with idiopathic dilated cardiomyopathy (n = 4) or ischemic heart disease (n = 4) during heart transplant procedure. Before aortic clamping, 99mTc-labeled human albumin microspheres were injected into the left atrium while arterial blood was sampled from the aorta at a constant rate. No complications were observed during or after the procedure. From the excised heart, myocardial slices for gamma camera imaging and well counting analysis were obtained. Myocardial blood flow was assessed by a well counter, correlated with the extent of fibrosis expressed as collagen per total tissue proteins obtained from 4-hydroxyproline and glycine as determined by high-performance liquid chromatography. Microsphere distribution, as seen by gamma camera images in a different slice, was correlated with the extent of fibrosis assessed by histological analysis of the same myocardial specimen. Mean transmural myocardial blood flow was 0.49 +/- 0.17 and 0.38 +/- 0.15 mL.min-1 x g-1 in idiopathic dilated cardiomyopathy and ischemic heart disease, respectively (P < .01). Endocardial-to-epicardial flow ratio was lower in ischemic heart disease than in idiopathic dilated cardiomyopathy patients (0.99 +/- 0.33 versus 1.16 +/- 0.30, P < .05). Mean myocardial fibrosis was 9 +/- 6% in idiopathic dilated cardiomyopathy and 25 +/- 28% in ischemic heart disease. In both groups, no correlation was found between myocardial blood flow values and the extent of fibrosis. In ischemic heart disease, regional myocardial blood flow was not significantly affected by the severity of coronary stenosis (< or = 70% or > 70%) either in the endocardium (0.44 +/- 0.24 versus 0.36 +/- 0.16 mL.min-1 x g-1, P = NS) or in the epicardium (0.50 +/- 0.33 versus 0.38 +/- 0.33 mL.min-1 x g-1, P = NS). By gamma camera imaging, transmural microsphere distribution appeared more homogeneous in idiopathic dilated cardiomyopathy than in ischemic heart disease (mean coefficient variation, 18% and 27%, respectively; P < .02); the severity of perfusion impairment did not correlate with the extent of fibrosis evaluated by histological criteria. CONCLUSIONS: Heart transplant surgery offers a valuable model to assess absolute myocardial perfusion in human heart failure. Myocardial blood flow is markedly depressed in failing hearts of both ischemic heart disease and idiopathic dilated cardiomyopathy patients; a different transmural myocardial blood flow distribution is observed in ischemic heart disease than in idiopathic dilated cardiomyopathy, with prevalent endocardial perfusion in the latter but not the former condition. In patients with end-stage heart failure, myocardial blood flow appears to be similarly impaired in fibrotic and viable regions. Mechanisms other than myocardial fibrosis and coronary lesions appear to operate in determining myocardial blood flow impairment in heart failure.

Adult↗
PubMed1991

In vivo detection of somatostatin receptors in patients with functionless pituitary adenomas by means of a radioiodinated analog of somatostatin ([123I]SDZ 204-090).

The recent availability of a Tyr3-substituted octreotide (SDZ 204-090) for radioiodination has allowed somatostatin (SRIH) receptor binding to be studied in vivo, and receptor-positive tumors of different origins to be visualized with a gamma-camera. This prompted us to investigate whether this compound could be used for external imaging of functionless pituitary adenomas displaying SRIH receptors. Eight patients with functionless pituitary adenomas, three patients with acromegaly, and three with macroprolactinoma were injected iv with 123I-labeled Tyr3-octreotide and then scanned with a gamma-camera. Positive scans were obtained in the three acromegalics and in two of the eight patients with functionless pituitary tumors. The patients with macroprolactinoma had negative scans. The diagnosis of functionless pituitary adenomas was confirmed by light and electron microscopic examination as well as immunocytochemical studies. In vitro binding of [125I]Tyr11-SRIH to cell membranes was evaluated in four functionless and three GH-secreting adenomas removed from seven of the patients. All of the GH-secreting as well as one of the four functionless adenomas had high affinity SRIH-binding sites, without differences in number or affinity, whereas SRIH-binding sites were not detected in the others. Positive scans were observed only in patients bearing tumors with high affinity SRIH-binding sites. In conclusion, [123I]Tyr3-octreotide appears to be a promising tool for singling out, in vivo, patients with functionless pituitary tumors displaying SRIH receptors who might potentially benefit from octreotide treatment.

Adenoma↗
PubMed1986

Observations on the natriuretic response to intravenous infusions of atrial natriuretic factor in water-loaded anaesthetized rats.

Natriuresis induced by infusions of atrial natriuretic factor (ANF) in water-loaded rats typically occurred in time sequences ('peak-and-shoulder' patterns) with an overlap of two different natriuretic responses. The first response was abrupt, short-lived and potentiated by angiotensin converting enzyme (ACE) inhibition. The second response was a gradual onset of natriuresis which lasted only as long as the ANF infusion and was directly correlated to the level of arterial blood pressure. This phenomenon explains the apparent loss of responsiveness to ANF bolus injections during a late phase. Atrial natriuretic factor facilitated excretion of intravenous salt loads, and the effect was also observed with low salt doses (1 microgram/h) which were below threshold for natriuresis when given alone. The data available so far suggest that ANF, apart from its effect on collecting-duct permeability, interferes with several control and feedback systems involved in sodium input into the collecting-duct system.

Animals↗
PubMed1986

[Interruption of the vena cava inferior. A comparative study of the Adams de Weese clip and the Kimray Greenfield filter].

Efficacy of two methods for interruption of inferior vena cava was compared after insertion of 95 Adams de Weese clips by the sub or trans-peritoneal route and of 72 Greenfield filters usually by a jugular approach. Introducing Greenfield's filter to produce caval interruption did not require modification of operative indications. In contrast, it allowed caval blockade to be performed in more elderly patients, generally in a poorer condition, at the price of higher mortality, due more to the clinical circumstances of the interruption rather than the caval blockade itself. Postoperative follow up showed fewer caval thromboses after Greenfield's filter (15%) than after the pericaval clip (35%).

Adult↗
PubMed1984

Usefulness of xerotomography in the diagnosis of acute pulmonary embolism.

The Authors report their experience in the study of pulmonary embolism by xerotomography. The use of tomography for the study of pulmonary vascularization is well known, but this method is by far less frequently used than pulmonary angiography and pulmonary perfusion and ventilation scintigraphy. The enhancement of contrasts and contours and the ample area of exposure are the features which render the images obtained by xerotomography similar to those achieved by pulmonary angiography. Our experience up to the present time allows us to state that xerotomography may represent a valid diagnostic means in cases of acute pulmonary embolism, when scintigraphy is not feasible or following scintigraphy, when doubts regarding the clinical diagnosis still remain.

Acute Disease↗
PubMed1983

[Anastomosis of the low popliteal and leg arteries without clamping].

Using an Esmarch's bandage and a lower thigh tourniquet makes it possible to suppress flow and backflow in arteries below the knees. Distal anastomosis without proximal and distal clamps can then be performed on arteries with pathological wall but with adequate residual lumen. The elective indication is bypass on partially calcified arteries of the leg.

Arteries↗
PubMed1983

The autonomic innervation of the human greater saphenous vein.

The existence of a double catecholaminergic and cholinergic innervation was demonstrated in the human greater saphenous vein. Catecholamine-containing nerve fibres are organized in a network-like plexus localized at the adventitial-medial border. Acetylcholinesterase-containing nerve fibres are arranged in a plexus found at the adventitial-medial border as well. Catecholamine and acetylcholinesterase-containing nerve fibres, while localized in close apposition since they occupy the same portion of the vein, represent two distinct and independent populations of nerve fibres coming likely from the sympathetic and parasympathetic sections of the autonomic nervous system respectively. Our findings demonstrating a close relationship between catecholaminergic and cholinergic nerve fibres within the wall of the human greater saphenous vein offer morphological support to physiological and pharmacological results reported in the literature of a presynaptic control exerted by cholinergic nerves on norepinephrine release at the level of the saphenous vein.

Acetylcholinesterase↗
PubMed1983

Assessment of sarcoidosis activity by 67gallium lung scan. A study with follow-up.

71 consecutive patients with histologically confirmed sarcoidosis, in various clinical stages of activity, were submitted to 67Ga lung scan, and 23 of them were studied with two or more scans at intervals of 4-6 months. In patients on steroid therapy, the drug was suspended 7 days before scan to avoid the steroids interfering with the gallium (Ga) uptake mechanism. In order to assess the usefulness of 67Ga in the evaluation of sarcoid activity, six other parameters of activity were considered, ranging from angiotensin-converting enzyme levels to progressive symptoms, from deteriorating X-ray or pulmonary function tests to clinical or laboratory evidence of prominent extra thoracic involvement. Our work suggests that Ga scan is more sensitive than chest X-ray in determining the degree and variation of pulmonary sarcoidosis activity, in evaluating the response to therapy, and in foreseeing the relapses. In some cases it gives information not detectable with other noninvasive criteria. The detection of patients with active disease, after discontinuation of steroids 7 days before scan, raises doubts about the opportunities of scanning patients on steroids, and suggests that further studies on this point are needed.

Adolescent↗
PubMed1980

Tomographic assessment of cerebral perfusion using a single-photon emitter (krypton-81m) and a rotating gamma camera.

Continuous carotid infusion of short-lived krypton-81m (t1/2 13 sec) yields an assessment of regional cerebral perfusion. This assessment can be obtained in three dimensions if activity is recorded with a rotating gamma camera and a computer to reconstruct krypton-81m distribution in tomographic sections. These showed several advantages over conventional views: (a) visualization of blood-flow distribution within brain structures (gray and white matter, basal ganglia); (b) more accurate location and evaluation of areas of relatively reduced or increased perfusion; (c) better definition of patterns of collateral circulation; (d) greater sensitivity and specificity in detecting and defining blood-flow changes during physiological activation studies. A limitation of the krypton-81m technique is its invasiveness. However, this study shows that the combination of new advances in radiochemistry with single-photon emission computed tomography may result in accessible methods for assessing, noninvasively and in three dimensions, the behavior of cerebral function in man.

Brain Diseases↗
PubMed1980

[Sequential scintigraphic evaluation in renal transplantation (author's transl)].

In a series of 57 renal transplantation of a sequential scintigraphy was carried out within the tenth day from surgical operation. According to the various scintigraphic findings and on the basis of the possible acute renal failure, the patients were subdivided into 7 groups and the data were correlated with clinical and hystological findings.

Acute Kidney Injury↗