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Biomedical subjects

F Fazio

Publications and source records attributed to F Fazio.

At least 235 records · Page 13Linked to original sources
PubMed1987

Cerebral arterial spasm after subarachnoid hemorrhage. A case report with SPECT and iodine-123 HIPDM.

Cerebral arterial spasm following subarachnoid hemorrhage can be responsible for secondary neurological deficits and can influence history, prognosis, and results of surgical treatment. The demonstration of vasospasm can be important for therapy. The use of I-123 HIPDM and SPECT in evaluating regional cerebral blood flow showed the effects on cerebral perfusion of diffuse arterial spasm in a case of subarachnoid hemorrhage and its recovery. There was a parallel with clinical neurological status.

Female↗
PubMed1987

Long-term noninvasive single photon emission computed tomography monitoring of perfusional changes after EC-IC bypass surgery.

The rCBF was evaluated using I-123 HIPDM and single photon emission computed tomography (SPECT) on 14 patients undergoing extracranial-intracranial (EC-IC) bypass surgery because of internal carotid artery (ICA) occlusion. Before surgery, all patients showed cortical areas of hypoperfusion over the affected cerebral hemisphere. Shortly after EC-IC bypass a rCBF increase was observed in six patients. However, at the 6 and 12 month follow-ups, with angiographic control of bypass patency, rCBF studies did not show any significant rCBF change. Long-term noninvasive tomographic monitoring of perfusion changes occurring after EC-IC bypass surgery failed to show a long-lasting improvement in perfusion.

Adult↗
PubMed1987

Regional extravascular density of the lung in patients with acute pulmonary edema.

The regional distribution of extravascular lung density (lung tissue and interstitial or alveolar fluid per unit thoracic volume) and fractional pulmonary blood volume (volume of blood per unit thoracic volume) was measured in five patients with acute interstitial pulmonary edema and two patients with acute alveolar edema. We found a uniform increase in extravascular lung density in the patients with acute interstitial edema but a preferentially dependent distribution in the patients with alveolar edema. Fractional blood volume had an abnormally uniform distribution in patients with interstitial edema. In alveolar edema, there was marked redistribution of blood volume away from severely edematous regions. The results are in agreement with previous experimental work with animal models. The distribution of extravascular lung density and fractional blood volume in subjects with acute interstitial edema is, however, different from that found in subjects with chronic interstitial edema, suggesting that the pathophysiological characteristics of the two conditions may be different.

Acute Disease↗
PubMed1987

Crossed cerebellar diaschisis in patients with cerebral ischemia assessed by SPECT and 123I-HIPDM.

Crossed cerebellar diaschisis (CCD) was investigated in a series of 59 patients (34 completed strokes and 25 reversible ischemic attacks, RIAs) using single photon emission computerized tomography (SPECT) with 123I-HIPDM as a cerebral blood flow (CBF) indicator. CCD was present in 17 (50%) of the patients with completed stroke and in 6 (24%) of the patients with RIAs. CCD was significantly correlated to the clinical severity (p less than 0.001) and to the extension of the supratentorial lesion (p less than 0.05). However, CCD was also recorded in 3 out of 16 patients with normal neurological examination and CT scan, suggesting that a 'functional' hemispheric disturbance may be sufficient to produce a remote effect on the contralateral cerebellar hemisphere. Time elapsed between the clinical onset and SPECT study was not critical, since CCD was recorded in the acute as well as in chronic studies. Follow-up SPECT studies showed that CCD disappeared in 5 out of 18 patients after a successful extra-intracranial bypass, while a spontaneous recovery was observed in only one of 16 nonsurgical patients.

Adult↗
PubMed1987

Development of nonreducible technetium-99m(III) cations as myocardial perfusion imaging agents: initial experience in humans.

A series of 15 nonreducible technetium-99m(III) complexes of formula tr-[99mTcL(Y)2]+ has been prepared by a general synthetic route based on reductive addition of Y to the technetium-99m (99mTc) intermediate [99mTcL(O)]+. In these complexes, selected for potential use as myocardial imaging agents, L represents one of the two tetradentate Schiff base ligands N,N'-ethylenebis(acetylacetone iminato), (en), or N,N'-propylene-1,2-bis(acetylacetone iminato), (pn), while Y represents a monodentate phosphine, phosphite or isonitrile ligand as exemplified by P(CH3)3, P(OCH3)3 and CN-C(CH3)3. Of these 15 complexes, several with octanol/saline partition coefficients in the range 0.04-20 exhibit significant myocardial uptake in rats and dogs. Of these, none exhibit detectable myocardial washout, providing strong support for the hypothesis that myocardial washout occurs only for those 99mTc(III) cations that undergo in vivo reduction to the neutral 99mTc(II) form. Evaluation of the prototypical complex tr-[99mTc(en)(P(CH3)3)2]+ in seven normal volunteers and patients establishes that it is only a mediocre myocardial imaging agent in man.

Animals↗
PubMed1986

Abnormal cardiovascular response to exercise in young asymptomatic diabetic patients with retinopathy.

Heart rate, blood pressure, and left ventricular ejection fraction (LVEF) were measured by means of Au 195 m first-pass angiocardiography, during maximal supine bicycle exercise in 20 young asymptomatic patients with insulin-dependent diabetes (IDD) (10 retinopathic and 10 uncomplicated) and in 10 control subjects. Five patients with retinopathic IDD also had mild subclinical autonomic neuropathy. Exercise capacity was diminished, although not significantly, in patients with retinopathic IDD. Heart rate and LVEF were similar in all groups at rest and at submaximal exercise. At peak exercise patients with retinopathic IDD had significantly lower heart rate (134 +/- 4 bpm) and LVEF (62.9 +/- 3.7%) than those with umcomplicated IDD (158 +/- 8 bpm and 76.6 +/- 2.4%, respectively) and control subjects (152 +/- 6 bpm and 73.5 +/- 1.9%, respectively). LVEF increased vs baseline in all control subjects and patients with uncomplicated IDD, but in only three with retinopathic IDD. Leg muscle blood flow (MBF) was also evaluated at rest and during exercise by 133Xe washout. Exercise MBF was significantly lower in patients with retinopathic IDD (40.5 +/- 2.23 ml X min-1 X 100 gm-1) than in control subjects (49.9 +/- 1.87 ml X min-1 X 100 gm-1) and in those with uncomplicated IDD (49.0 +/- 1.87 ml X min-1 X 100 gm-1). Diffuse microangiopathy, alone or in combination with neuropathy, might be responsible for the impairment of cardiovascular function in diabetes.

Adult↗
PubMed1986

Sequential assessment of regional cerebral blood flow, regional cerebral blood volume, and blood-brain barrier in focal cerebral ischemia: a case report.

Regional CBF (rCBF) and regional cerebral blood volume (rCBV) were evaluated by N,N,N'-trimethyl-N'-(2)-hydroxy-3-methyl-5-[123I]iodobenzyl-1, 3-propanediamine-2 HCl- and 99mTC-labeled red blood cells, respectively, and single-photon emission computerized tomography (SPECT) in a patient with focal cerebral ischemia. Sequential transmission computerized tomography (TCT) and SPECT functional data were compared with clinical findings to monitor the pathophysiological events occurring in stroke. A lack of correlation between rCBF-rCBV distributions and blood-brain barrier (BBB) breakdown was found in the acute phase. In the face of more prolonged alteration of BBB, as seen by TCT enhancement, a rapid evolution of transient phenomena such as luxury perfusion was shown by SPECT studies. Follow-up of the patient demonstrated a correlation between the neurological recovery and a parallel relative improvement of the cerebral perfusion.

Adult↗
PubMed1986

Beclomethasone dipropionate does not affect mucociliary clearance in patients with chronic obstructive lung disease.

Aerosolized steroids may be implicated in the increased incidence of chest infections. To evaluate such a possibility, we utilized a double-blind study to investigate the acute effect of inhaled beclomethasone dipropionate on mucociliary clearance in 10 patients with chronic obstructive lung disease (5 receiving the drug and 5 placebo). Mucociliary clearance was measured by inhalation of a 99mTc-labelled albumin aerosol. The resulting radioactivity was recorded externally by a large-field gamma camera and dedicated computer for 3 consecutive hours without patient repositioning. After 1-hour baseline recording, the subjects inhaled from a commercial pressurized canister either beclomethasone dipropionate (250 micrograms) or vehicle alone. The recording was then continued for 2 more hours. No statistically significant difference was found in clearance rates throughout the entire period of observation between patients receiving beclomethasone and controls. The data suggest that mechanisms other than mucociliary function impairment are responsible for the increased incidence of chest infections which may accompany steroid treatment by the inhalatory route.

Adult↗
PubMed1986

Evaluation in dogs and humans of three potential technetium-99m myocardial perfusion agents.

The biodistribution of the three cationic 99mTc complexes [99mTc(TMP)6]+, [99mTc(POM-POM)3]+, and [99mTc(TBIN)6]+--where TMP represents trimethylphosphite, POM-POM represents 1,2-bis(dimethyoxyphosphino)ethane, and TBIN represents t-butylisonitrile--have been evaluated in humans and dogs. Each agent was studied in three normal volunteers at rest, while [99mTc(POM-POM)3]+ and [99mTc(TBIN)6]+ were each studied in one normal volunteer at exercise. Even though all three agents yield good myocardial images in dogs, none appear suitable for clinical use as myocardial perfusion imaging radiopharmaceuticals. In humans, [99mTc(TMP)6]+ and [99mTc(POM-POM)3]+ clear very slowly from the blood and provide myocardial images only several hours after injection. [99mTc(TBIN)6]+ clears rapidly from the blood, but accumulation in the lung obscures the myocardial image for the first hour after injection; at later times, activity in the liver and spleen masks the apical wall. These results correlate with the blood-binding properties of the three complexes. [99mTc(TMP)6]+ and [99mTc(POM-POM)3]+ bind tightly to the plasma of human blood, but not to the plasma of dog blood; [99mTc(TBIN)6]+ does not bind tightly to the plasma of either dog or human blood. Among the Tc(I) complexes studied to date in humans, [99mTc(TBIN)6]+ appears to be unique in biodistribution pattern, blood-binding properties, and the fact that exercise improves the ultimate myocardial image. All the Tc(I) complexes appear to undergo myocardial accumulation by a mechanism different from that utilized by Tc(III) complexes. Animal studies alone are not adequate to evaluate the potential utility of 99mTc cationic complexes for myocardial perfusion studies.

Animals↗
PubMed1985

Metabolic and kinetic considerations in the use of [125I]HIPDM for quantitative measurement of regional cerebral blood flow.

The metabolic degradation and the kinetics of the cerebral uptake of N,N,N'-trimethyl-N'-(2-hydroxy-3-methyl-5-[125I]iodobenzyl)-1, 3-propanediamine ([125I]HIPDM) have been studied in conscious, adult male Sprague-Dawley rats to determine its suitability as a tracer for the quantitative measurement of regional CBF (rCBF). rCBF was calculated by the indicator fractionation and the tissue equilibration methods in experiments of different durations up to 1 h. The values of rCBF obtained with [125I]HIPDM were compared with those obtained in concurrent measurements with [14C]iodoantipyrine in the same animals. Results of the experiments demonstrate that [125I]HIPDM is an inadequate tracer for use with the indicator fractionation method and that any method that employs [125I]HIPDM for the determination of rCBF must take into account its metabolic degradation, diffusion limitations, and bidirectional flux across the blood-brain barrier. With the tissue equilibration method, consistent determinations of rCBF may be possible with [125I]HIPDM by measurement of the time course of its concentration in arterial blood, corrected for the presence of 125I-labeled metabolic products, and its concentration in the brain at any time up to 1 h after its administration. The method may be adapted to measure rCBF in humans by means of single-photon emission tomography with [123I]HIPDM.

Animals↗
PubMed1984

Quantitative radionuclide angiocardiography using gold-195m.

A limitation of first-pass radionuclide angiocardiography is the limited repeatability because of the relatively long half-life of technetium-99m (Tc-99m). The feasibility, reproducibility and validity of multiple sequential quantitative first-pass studies were assessed in humans using the short-lived isotope gold-195m (Au-195m) (half-life of 30.6 seconds, 262 keV), which can be directly obtained from a generator made of its parent isotope, mercury-195m (half-life of 41.6 hours). Thirty-three subjects (13 normal volunteers and 20 cardiac patients) were studied using a large-field gamma camera equipped with a medium-energy collimator. After Au-195m intravenous injections, repeat first-pass studies were performed in the left anterior oblique projection. A left anterior oblique study was then obtained after i.v. injection of Tc-99m. Left ventricular ejection fraction calculations were performed separately by 2 observers. Reproducibility of Au-195m first-pass studies was excellent. The correlation coefficients for left ventricular ejection fraction from the first and the second Au-195m injections were 0.93 and 0.98 for observers 1 and 2, respectively. The correlation coefficients between Au-195m and Tc-99m first-pass studies were 0.95 and 0.98, respectively.

Adult↗
PubMed1984

Preparation and evaluation of [99mTc]DEPE as a cardiac perfusion agent.

Technetium-99m labeled bis(1,2-diethylphosphino)ethane was evaluated as a cardiac perfusion agent in mice, dogs and normal human volunteers. The agent produced as a single cationic compound was prepared by a simple kit type method and had a rapid myocardial uptake in animals. The cardiac uptake of the agent in dogs averaged 4.6% of administered dose and delineated left and right ventricles by in vivo imaging. In dogs with experimental myocardial infarction, the agent was distributed according to the regional myocardial blood flow, had excellent correlation with myocardial distribution of 85Sr microspheres (r = 0.96, 0.93)] and 201Tl (r = 0.91 and 0.83), and enabled us to detect perfusion defects by in vivo scintigraphy. The agent, however, failed to have a useful degree of cardiac uptake in humans.

Animals↗
PubMed1984

Tomographic assessment of regional cerebral perfusion using intravenous I-123 HIPDM and a rotating gamma camera.

The feasibility of assessing regional cerebral perfusion using the new brain imaging agent N,N,N'-trimethyl-N'-(2)-hydroxy-3-methyl-5-(123I) iodobenzyl)-1,3-propanediamine 2 HCl (I-123 HIPDM) and single photon emission computed tomography (SPECT) was evaluated in normal subjects and patients with cerebrovascular disorders. Following intravenous injection, I-123 HIPDM was rapidly extracted from the circulating blood by the brain (6.7%) and other organs. Its intracerebral distribution, as tomographically assessed by SPECT with a rotating gamma camera, reflected the distribution of blood flow within brain structures (gray and white matter, basal ganglia, etc.). Asymptomatic patients with history of transient ischemic attacks or minor stroke and angiographic evidence of internal carotid artery occlusion showed large cortical areas of reduced I-123 HIPDM distribution with normal or slightly positive CT. After extracranial-intracranial bypass surgery, reperfusion could be shown in previously ischemic areas. This study indicates the clinical usefulness of using I-123 HIPDM and gamma camera SPECT for the functional evaluation of brain disorders.

Adult↗
PubMed1984

Acute effect of inhaled salbutamol on mucociliary clearance in health and chronic bronchitis.

We investigated in a double-blind study the acute effect of the inhaled beta 2-adrenergic agent salbutamol on mucociliary clearance in man. Subjects were 20 patients with chronic bronchitis (10 receiving the drug and 10 placebo) and 6 healthy individuals (3 receiving the drug and 3 placebo). Mucociliary clearance was evaluated after inhalation of a pressurized 99mTc-labelled a albumin aerosol (median mass aerodynamic diameter 2.85 microns). Particle deposition and clearance was determined by external recording with a large-field gamma camera and dedicated computer, for three consecutive hours without moving the subject. After 1 h baseline clearance recording the subject was given either salbutamol (500 micrograms) or vehicle alone from a commercial pressurized nebulizer; recording was then continued for a further 2 h (test period). Both patients and normals treated with salbutamol showed a significant increase in the rate of clearance when compared with their respective control group receiving placebo. Clearance rates (percentage activity cleared per hour) from the lungs in the hour after salbutamol inhalation averaged 33.1% +/- 13.5 (SD) per hour, for patients (control 12.2% +/- 5.6 (SD) per hour, p less than 0.001) and 16.1% +/- 4.3 (SD) per hour for normals (control 7.8% +/- 2.0 (SD) per hour, (p less than 0.005). Significant differences were also found in clearance rate before and after salbutamol inhalation in both treated groups. Cough events did not produce any significant effect on average mucociliary clearance. However, visualization of serial computer images in individual patients showed that cough may generate appreciable upward, downward or even lung-to-lung movements of radioactive boli.

Adult↗
PubMed1983

Regional extravascular lung density and fractional pulmonary blood volume in patients with chronic pulmonary venous hypertension.

Using a technique based on positron transmission and emission tomography, we measured regional extravascular lung density (lung tissue and interstitial water per unit thoracic volume) and fractional pulmonary blood volume (volume of blood per unit thoracic volume) in normal subjects and in patients with cardiomyopathy and chronic pulmonary venous hypertension. We found an increase in extravascular lung density in the patients. Extravascular density was increased in all parts of the lung studied, but higher values were seen in the dorsocaudal portion than in the ventrocaudal portion of the lung (average 151% and 130% of normal, respectively). Fractional blood volume was markedly reduced in the dorsocaudal part of the lung (mean 74% of normal). The increase in extravascular density probably reflects structural changes in the lung as well as accumulation of interstitial fluid. The distribution of extravascular density is consistent with previous radiological and morphological studies, and may reflect a higher tendency to oedema formation in the dependent parts of the lung. The measurements of fractional blood volume suggest that intrapulmonary blood volume is reduced in chronic pulmonary venous hypertension. This may reflect a decrease in the distensibility of the pulmonary vessels due to structural abnormalities, as well as functional changes in the pulmonary vasculature.

Adult↗