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Biomedical subjects

M Pistolesi

Publications and source records attributed to M Pistolesi.

At least 37 records · Page 2Linked to original sources
PubMed1996

Value of perfusion lung scan in the diagnosis of pulmonary embolism: results of the Prospective Investigative Study of Acute Pulmonary Embolism Diagnosis (PISA-PED).

To assess the value of perfusion lung scan in the diagnosis of pulmonary embolism, we prospectively evaluated 890 consecutive patients with suspected pulmonary embolism. Prior to lung scanning, each patient was assigned a clinical probability of pulmonary embolism (very likely, possible, unlikely). Perfusion scans were independently classified as follows: (1) normal, (2) near-normal, (3) abnormal compatible with pulmonary embolism (PE+: single or multiple wedge-shaped perfusion defects), or (4) abnormal not compatible with pulmonary embolism (PE-: perfusion defects other than wedge-shaped). The study design required pulmonary angiography and clinical and scintigraphic follow-up in all patients with abnormal scans. Of 890 scans, 220 were classified as normal/or near-normal and 670 as abnormal. A definitive diagnosis was established in 563 (84%) patients with abnormal scans. The overall prevalence of pulmonary embolism was 39%. Most patients with angiographically proven pulmonary embolism had PE+ scans (sensitivity: 92%). Conversely, most patients without emboli on angiography had PE- scans (specificity: 87%). A PE+ scan associated with a very likely or possible clinical presentation of pulmonary embolism had positive predictive values of 99 and 92%, respectively. A PE- scan paired with an unlikely clinical presentation had a negative predictive value of 97%. Clinical assessment combined with perfusion-scan evaluation established or excluded pulmonary embolism in the majority of patients with abnormal scans. Our data indicate that accurate diagnosis of pulmonary embolism is possible by perfusion scanning alone, without ventilation imaging. Combining perfusion scanning with clinical assessment helps to restrict the need for angiography to a minority of patients with suspected pulmonary embolism.

Adolescent↗
PubMed1996

Lazaroid U-74389F attenuates phorbol ester-induced lung injury in rabbits.

We examined the effect of the antioxidant lazaroid U-74389F on acute lung injury induced in rabbits by phorbol myristate acetate (PMA). Thirty minutes after receiving either U-74389F (15 mg.kg-1 i.v.) or U-74389F vehicle, rabbits (n = 60) were given PMA (60 micrograms.kg-1 i.v.). PMA vehicle injected rabbits (n = 20) served as controls. Over a 5 h period after PMA or PMA vehicle injection, we measured arterial pH, arterial oxygen tension (Pa,O2), arterial carbon dioxide tension (Pa,CO2), and the plasma concentration of the neutrophil chemoattractant interleukin-8 (IL-8). At postmortem, lungs were inspected for macroscopic injury and examined histologically. Malondialdehyde levels were assayed in lung tissue as an index of lipid peroxidation. In bronchoalveolar lavage (BAL), total and differential cell counts, protein and IL-8 concentrations were measured. Compared to normal controls, rabbits challenged with PMA alone developed arterial acidosis, hypercapnia and hypoxaemia, accompanied by significant rise in plasma IL-8 concentration. U-74389F pretreated animals did not develop significant arterial blood gas abnormalities and had significantly lower IL-8 concentration in plasma. U-74389F did not prevent PMA-induced lipid peroxidation. However, macroscopic signs of lung injury and the degree of alveolar haemorrhage and protein extravasation were significantly less severe in pretreated rabbits than in those given PMA alone. In addition, U-74389F significantly reduced IL-8 concentration and neutrophil number in BAL. By histological assessment, 80% of lung neutrophils were localized in alveolar spaces of animals receiving PMA alone. Conversely, in U-74389F pretreated animals, 75% of neutrophils were distributed within extra-alveolar blood vessels and alveolar septa. We conclude that lazaroid U-74389F attenuates lung injury in rabbits given PMA by preventing neutrophil migration into pulmonary alveoli. This effect may, in part, be related to downregulation of IL-8 production.

Animals↗
PubMed1996

Mitochondria act as a reservoir for the basic amine HIPDM in the lung.

The lungs are a site for the uptake, accumulation, and storage of exogenous basic amines. The compound N-N-N'-trimethyl-N'-(2-hydroxy-3-methyl-5-iodobenzyl)-1,3 propanediamine (HIPDM) is a basic amine that can be labelled with radioactive iodine and detected by external counting. Intravenously injected 123I-HIPDM is extracted by the human lung, where it is retained in a slowly effluxable pool. In the present study, we measured HIPDM lung kinetics and subcellular distribution in rabbits given i.v. 125I-HIPDM. Rabbits were killed from 2 min to 5 h after injection, and the radioactivity retained in their lungs was measured. Subcellular lung fractions (nuclear, mitochondrial, lysosomal, microsomal and postmicrosomal supernatant) were assayed for HIPDM radioactivity, protein content, and distribution of specific marker enzymes. HIPDM lung clearance in rabbits was nearly identical to that of humans. Virtually all the HIPDM radioactivity in lungs (98+/-1%) was associated with subcellular membranous structures. The highest HIPDM specific radioactivity was found in the mitochondrial fraction, and the subcellular distribution profile closely resembled that of the mitochondrial marker enzyme succinate cytochrome c reductase. No redistribution of HIPDM among subcellular compartments was observed over a 5 h period after injection. The data indicate that mitochondria act as reservoir for HIPDM in the lungs and contribute to the pulmonary persistence of this compound. HIPDM can be used to investigate the pulmonary uptake of basic amines in health and in lung disease.

Animals↗
PubMed1995

Radiologic evaluation of emphysema in patients with chronic obstructive pulmonary disease. Chest radiography versus high resolution computed tomography.

To objectively reappraise the role of the chest radiograph (CXR) in the clinical assessment of emphysema, we compared a standardized reading of CXR with both a visual scoring and a quantitative analysis of high resolution computed tomography (HRCT) of the chest in 46 consecutive patients with chronic obstructive pulmonary disease (COPD) and fixed expiratory airflow limitation. CXR were scored for signs of overinflation and pulmonary vascular deficiency by three independent observers. HRCT scans were independently scored for extent of emphysema and for both severity and extent of emphysema. In 28 of 46 patients, inspiratory and expiratory HRCT scans were analyzed quantitatively by measuring the mean CT number in Hounsfield Units (HU) and the percentage of lung area with CT numbers < -900 HU. Quantitative CT data were compared with reference values obtained in seven normal nonsmokers. The CXR score of emphysema showed a highly significant interobserver reproducibility and correlated linearly (p < 0.001) with HRCT visual scores and quantitative data from both inspiratory and expiratory CT scan. CXR score correlated with functional indices of airflow obstruction, overinflation, and impaired lung diffusing capacity in a way comparable to that obtained by using qualitative and quantitative CT data. Patients with no signs of emphysema on CXR had mean expiratory CT numbers within normal range and a fraction of lung area with CT numbers < -900 HU on expiratory scan not exceeding 15% of total cross-sectional area. The latter value was consistently greater than 15% in patients with CXR score > 0.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Imaging strategies in the detection and evaluation of ARDS.

Considerable evidence has accumulated indicating that the chest radiograph is the most reliable imaging technique to evaluate the severity of lung edema in patients with established ARDS. Recently, the radiographic approach has been validated by direct comparison of an x-ray score of edema with the densitometric analysis of lung CT scan images. CT scanning may prove useful in quantitating the amount of residual healthy lung and in evaluating the effectiveness of PEEP in patients with acute respiratory failure. The application of CT scanning in these patients should be further expanded. Special effort should be made to evaluate unanesthetized, spontaneously breathing patients and to correlate CT quantitative data with the simultaneous analysis of portable chest radiographs in order to enhance the physician's ability to extract valuable, physiologic information from the chest film in critically ill patients. In order to improve the survival rate of patients with ARDS, methods are needed which detect ARDS at its earliest clinical stage. A number of radioisotopic techniques have been developed, based on the evaluation of the leakiness of the alveolar-capillary barrier either from the vascular or from the airspace side. Clearance of aerosolized DTPA from airspaces, although extremely sensitive, is not specific for ARDS in as much as factors other than lung injury may equally affect the rate of DTPA clearance from the lung. External detection of transvascular protein flux may serve as noninvasive means to assess the integrity of the lung microvascular endothelial barrier.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood-Air Barrier↗
PubMed1993

The assessment of respiratory function in a patient with dyspnoea and severe hypoxaemia.

In the investigation of dyspnoea and severe hypoxaemia the clinical relevance of multiple diagnostic techniques was studied. The patient was sequentially studied utilizing several techniques. The degree of lung impairment by spirometry, diffusing capacity for carbon monoxide, haemodynamics, pulmonary gas exchange, ventilation-perfusion relationships assessed by the multiple inert gases elimination techniques, ventilation and perfusion lung scans, gallium 67 scintigraphy, bronchoalveolar lavage and high resolution computerized tomography, twice over a period of 12 months during recovery under treatment. A marked impairment of pulmonary gas exchange was first explained by diffusion impairment and ventilation-perfusion mismatch. The multiple inert gas elimination technique allowed determination of the cause of hypoxaemia by ventilation-perfusion inequality. A pathological correlate of the ventilation-perfusion inequality was the appearance of honeycomb lungs detected by high resolution computed tomograph and active alveolitis by bronchoalveolar lavage. All results were consistent with a diagnosis of fibrosing alveolitis. The patient was evaluated again during treatment. Some functional improvement occurred despite persistence of the same pathological findings. In conclusion, this study demonstrates the value of information derived from different tests. Physiological correlations complemented by pathological observations expand understanding of the pathogenesis of disease. These procedures contribute to understanding mechanisms responsible for functional impairment.

Bronchoalveolar Lavage Fluid↗
PubMed1991

Evaluation of pulmonary vascular pressures in cardiac patients: the role of the chest roentgenogram.

In 77 patients (34 with left heart valvulopathy, 17 with dilated cardiomyopathy, and 26 with chronic coronary artery disease) pulmonary vascular pressures were estimated from the chest film by means of a new scoring system. Standard chest x-ray films taken immediately before diagnostic right and left cardiac catheterization were analyzed independently by three readers without knowledge of the hemodynamic findings. The radiographic signs were subdivided into three groups as follows, and to each one a score derived from a retrospective statistical analysis was attributed: (A) signs of interstitial edema, (B) patterns of pulmonary blood flow distribution, and (C) alterations in the pulmonary arteries. The sum of the scores of groups A and B x-ray findings correlated well with pulmonary wedge pressure, and the sum of the scores of groups A, B, and C correlated more strongly with the mean pulmonary artery pressure. These results confirm that it is possible, in patients with chronic heart disease, to assess accurately the pulmonary artery and wedge pressures by means of the noninvasive and easily performed chest roentgenogram.

Blood Pressure↗
PubMed1991

The value of portable chest roentgenography in adult respiratory distress syndrome. Comparison with computed tomography.

In 17 patients with adult respiratory distress syndrome, we used data derived from computed tomographic (CT) scan densitometric analysis to validate the value of portable chest roentgenograms in objectively estimating the amount of pulmonary edema. Chest roentgenograms and CT scans were taken in the same ventilatory conditions (apnea at 10 cm H2O of positive end-expiratory pressure [PEEP]); blood gas samples and hemodynamic parameters were collected at the same time. Roentgenographic analysis was undertaken by independent observers using two standardized scoring systems proposed in the literature. CT scan analysis was performed using the CT number frequency distribution and the gas lung volume (measured by helium dilution technique) to estimate quantitatively the lung density, the lung weight, and the percentage of normally aerated and nonaerated tissue. Knowing the mean CT number of the pulmonary parenchyma in a group of normal subjects, we also inferred the ideal lung weight expected in the study population and computed the excess tissue mass as the difference between actual and ideal lung weight. Both the roentgenographic scoring systems showed direct correlation with the pulmonary impairment as detected by CT scan densitometric analysis (CT number, percentage of nonaerated tissue, lung weight, and excess tissue mass; p less than 0.01) and inverse relation with the percentage of normally aerated tissue (p less than 0.01). We also found a relationship between roentgenographic scores and the impairment in gas exchange as detected by shunt fraction (p less than 0.05). We conclude that standardized reading of portable chest roentgenograms by means of scoring tables is a valuable tool in estimating the amount of pulmonary edema in a patient with adult respiratory distress syndrome.

Absorptiometry, Photon↗
PubMed1991

Nuclear medicine in ARDS: clinical applications.

ARDS is still characterized by an exceedingly high mortality rate. Methods are then needed to detect ARDS at the earliest clinical stage. Over the last decade, radioisotopic techniques have developed, aimed at demonstrating an abnormal neutrophil sequestration in the lung or detecting functional alterations of the pulmonary alveolar-capillary barrier, which likely precede the onset of respiratory distress. Preliminary application of these techniques in patients with ARDS yielded conflicting results in terms of sensitivity and specificity. On the contrary, lung vascular abnormalities have been consistently observed in patients with ARDS studied by perfusion lung scanning. They consist of focal, non segmental perfusion defects, mostly peripheral and dorsal, with redistribution of blood flow to non-dependent lung regions. This scintigraphic pattern may be considered typical of ARDS since it is not observed in other acute lung disorders. Perfusion abnormalities on lung scans are detectable from the very early stage of ARDS and correlate with the severity of the syndrome as reflected by gas exchange, central hemodynamics, and chest radiography. Perfusion lung scanning may then be used in the early detection and evaluation of vascular injury in ARDS.

Endothelium, Vascular↗
PubMed1989

Lung tissue binding of iodobenzyl-propanediamine: involvement of beta-adrenergic receptors.

The basic compound N-N-N'-trimethyl-N'-(2-hydroxy-3-methyl-5-iodobenzyl)-1,3- propanediamine (HIPDM) accumulates in human and rabbit lungs, where it forms a slowly effluxable pool. In isolated perfused rat lung, HIPDM is taken up by a saturable, energy-independent mechanism, which is competitively inhibited by imipramine, chlorpromazine and propranolol. To ascertain whether beta-adrenergic receptors are involved in the binding process of HIPDM to lung tissue, the ability of unlabelled HIPDM to displace the beta-adrenergic receptor ligand [125I]iodocyanopindolol (ICYP) from rabbit lung beta-receptors was examined. Lung microsomal membrane fractions (75 micrograms ml-1) were incubated at 37 degrees C for 3 h with 68 pM ICYP (with or without 1 microM of (+/-)-propranolol) in the presence of HIPDM (10(-10)-10(-3) M). Bound and free radioactivity were separated through glass-fibre filters and the retained radioactivity was counted in a gamma-spectrometer. HIPDM competed with ICYP for beta-adrenoceptors (13% displacement at 10(-5) M. 50% at 5 x 10(-5) M, and 90% at 2 x 10(-4) M). The inhibition curve of ICYP binding by HIPDM was similar to that observed for (-)-noradrenaline. Although the results of the in vitro studies cannot be extrapolated to in vivo conditions, they suggest that beta-adrenergic receptors may be involved in the observed lung uptake of the basic amine HIPDM.

Animals↗
PubMed1988

Objective radiographic criteria to differentiate cardiac, renal, and injury lung edema.

To assess the value of the chest radiograph in differentiating various types of pulmonary edema, we retrospectively analyzed 119 films of patients with pulmonary edema caused by left heart decompensation (group 1;N = 56), renal failure (group 2; N = 19), and lung microvascular injury (group 3; N = 44). Chest radiographs were examined independently by two trained observers, unaware of the clinical diagnosis, according to a standardized reading table. The two observers assigned chest films to the corresponding group with an accuracy of 86% and 90%, respectively. To test the observers' objectivity, we used radiographic findings as input variables for discriminant analysis. Computer-generated numerical functions identified pulmonary edema etiology with an accuracy of 88% when considering the three groups together. When groups were compared as pairs, percentages of correct classification were 91% (group 1 vs. group 2), 93% (group 1 vs. group 3), and 100% (group 2 vs. group 3). Thus, a standardized reading of chest radiographs may be considered a reliable clinical method for identifying pulmonary edema etiology.

Heart Failure↗
PubMed1988

Theoretical and practical considerations of measuring extravascular lung water.

The volume of extravascular lung water is currently measured in vivo from the difference in mean transit times of the extrapolated first-pass dilution curves of two indicators, one diffusible and the other confined to the intravascular space. To overcome the limitations of this method, one can prolong the measurement interval, introduce a highly diffusible indicator, or both. In the first case, recirculating indicators are measured and included in the computation by deconvolution of the mean transit time through the lung. In the second case, heat is used as the water indicator. In the third case, not yet explored, recirculating heat would be measured and long thermal transit times uncovered. In view of the complexity of the deconvolution method and the pitfalls of the thermal dilution method, a radiographic score of pulmonary edema may be more useful clinically to assess the volume of extravascular lung water in patients with heart disease or adult respiratory distress syndrome.

Animals↗
PubMed1988

Factors affecting regional pulmonary blood flow in chronic ischemic heart disease.

To assess the effect of left heart disease on pulmonary blood flow distribution, we measured mean pulmonary arterial and wedge pressures, cardiac output, pulmonary vascular resistance, pulmonary blood volume, and arterial oxygen tension before and after treatment in 13 patients with longstanding ischemic heart failure and pulmonary edema. Pulmonary edema was evaluated by a radiographic score, and regional lung perfusion was quantified on a lung scan by the upper to lower third ratio (U:L ratio) of pulmonary blood flow per unit of lung volume. In all cases, redistribution of lung perfusion toward the apical regions was observed; this pattern was not affected by treatment. After treatment, pulmonary vascular pressures, resistance, and edema were reduced, while pulmonary blood volume did not change. At this time, pulmonary vascular resistance showed a positive correlation with the U:L ratio (r = 0.78; P less than 0.01), whereas no correlation was observed between U:L ratio and wedge pressure, pulmonary edema, or arterial oxygen tension. Hence, redistribution of pulmonary blood flow, in these patients, reflects chronic structural vascular changes prevailing in the dependent lung regions.

Blood Volume↗
PubMed1988

Reabsorption kinetics of albumin from pleural space of dogs.

The reabsorption of albumin from the pleural space was measured in eight dogs receiving 0.5 ml intrapleural injection of 131I-labeled albumin and a simultaneous intravenous injection of 125I-labeled albumin. Plasma curves for both tracers were obtained over 24 h. The 125I-albumin curve served as input function of albumin for interstitial spaces, including pleura, whereas the 131I-albumin curve represented the output function from pleural space. The frequency function of albumin transit times from pleural space to plasma was obtained by deconvolution of input-output plasma curves. Plasma recovery of 131I-albumin was complete by 24 h, and the mean transit time from pleura to plasma averaged 7.95 +/- 1.57 (SD) h. Albumin reabsorption occurred mainly via lymphatics as indicated by experiments in 16 additional dogs in which their right lymph ducts or thoracic ducts were ligated before intrapleural injection. A pleural lymph flow of 0.020 +/- 0.003 (SD) ml.kg-1.h-1 was estimated, which is balanced by a comparable filtration of fluid into the pleural space. This suggests that, under physiological conditions, the subpleural lymphatics represent an important control mechanism of pleural liquid pressure.

Absorption↗
PubMed1988

Intrapleural liquid flow down a gravity-dependent hydraulic pressure gradient.

We studied the vertical movement of 2 mg technetium-labeled albumin injected intrapleurally in 0.5 ml saline (15% of pleural liquid volume) in eight spontaneously breathing anesthetized dogs subject to a sudden change in posture (prone to supine or vice versa). The albumin movements were evaluated through a large field gamma camera placed laterally to the animal and detecting total (AT) and regional activities from two superimposed equal areas (At and Ab, top and bottom, respectively). The At/Ab ratio decreased from 2.1 to 1.3 in four animals up to 20 min from the change in posture and from 0.9 to 0.5 in four more animals studied from 50 to 90 min from turning maneuver. The rate of change in At and Ab was similar in the two groups of animals and unaffected by the acquisition posture. AT decreased by 7.7 and 3.5% for the two groups, respectively, reflecting albumin clearance from the pleural space. The opposite time course of regional activities and the independence of their rate of change of the At/Ab ratio and of the animal posture suggest a top-to-bottom albumin transfer occurring through a bulk flow of liquid estimated at 0.006 ml.kg-1.h-1. The data are consistent with a measured vertical pleural liquid pressure gradient that does not reflect a hydrostatic condition.

Animals↗