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Biomedical subjects

L Marsili

Publications and source records attributed to L Marsili.

At least 37 records · Page 2Linked to original sources
PubMed1995

Interspecies differences in mixed function oxidase activity in birds: Relationship between feeding habits, detoxication activities and organochlorine accumulation.

The relationship between feeding habits and interspecies differences in the detoxication ability of the mixed function oxidase (MFO) system was investigated in birds. The role of MFO (particularly aldrin epoxidase activity) in the detoxication/bioaccumulation of organochlorines was also investigated. Euriphagic (yellow-legged herring gull (Larus cachinnans), black-headed gull (Larus ridibundus), jackdaw (Corvus monedula), magpie (Pica pica) and stenophagic (cormorant (Phalacrocorax carbo), coot (Fulica atra) and sparrow (Passer italiae)) species were collected in northern and central Italy. The following liver microsomal monooxygenase activities were measured: aldrin epoxidase, ethoxyresorufin dealkylation (EROD), benzyloxyresorufin dealkylation (BROD) and pentoxyresorufin dealkylation (PROD). NADPH-and NADH-cytochrome c reductase (NAD(P)H-CYT-CRED) and NADH-ferricyanide reductase (NADH-FERRIRED) activities were also measured in the liver microsomal fraction. Glutathione concentration (GSH) was measured in the liver cytosolic fraction. As a marker of liver damage gamma-glutamyl transpeptidase (GGTP) activity was assayed in the serum. The residues of organochlorines (HCB, pp'DDTs and PCBs) were determined in muscle samples. Omnivorous species, particularly the yellow-legged herring gull, had the highest aldrin epoxidase activities. In the yellow-legged herring gull the activity was approximately twice as high as in the jackdaw (p < 0.05), black-headed gull (p < 0.05) and coot (p < 0.05). Values five times lower were detected in the specialist fish-eater, the cormorant (p < 0.001). The lowest values of aldrin epoxidase activity were detected in the sparrow. Feeding habits were found to be related to evolutionary interspecies differences in MFO activity. A significant statistical correlation (r = 0.656) was found between the 'omnivore index' and MFO detoxication activity expressed as aldrin epoxidation. Organochlorines, and particularly PCBs, were higher in cormorants and yellow-legged herring gulls from a polluted lagoon than in the other species analysed (black-headed gull p < 0.01; sparrow p < 0.001; jackdaw p < 0.01; coot p < 0.001). Levels of pp'DDE were much higher in the cormorant and sparrow than in the other birds. Knowledge of the different species-specific detoxication abilities was found to be a useful tool for the identification of species potentially at risk in environments with high pollution by chlorinated hydrocarbons, or in general contaminants metabolized by the MFO system.

Journal Article↗
PubMed1994

[Characterization of hypertrophic cardiomyopathy with magnetic resonance].

We selected 15 patients with hypertrophic cardiomyopathy (HCM) and 5 with secondary myocardial hypertrophy (SMH). All patients were examined by means of Magnetic Resonance Imaging (MRI) and echocardiography. The MR study was performed with gated T1- and T2-weighted spin echo sequences and cine MRI. We correlated echocardiographic and MRI measurements and found a correlation coefficient (R) of 0.72 for apex thickness, r = 0.84 for posterior wall thickness, 0.76 for the lateral wall and 0.89 for the area at papillary level. Cine MR acquisitions showed signal loss in the systolic phase at the outflow tract in 9 obstructive HCM patients, which was consistent with echocardiographic color Doppler findings. The signal intensity of myocardial tissue was analyzed with MRI. The values were correlated with those of the skeletal muscle. We performed the paired sample t-test on T1- and T2-weighted spin echo sequences between the signal at the septum and that of the free wall in the 15 HCM patients. The analysis showed significant differences on T2-weighted sequences (p < 0.02). Unpaired t-test was performed between the 15 HCM and the 5 SMH patients; the analysis showed significant differences on both T1- (p < 0.01) and T2-weighted sequences (p < 0.04).

Adult↗
PubMed1993

[Angiography with magnetic resonance of the ++carotid arteries. Evaluation of clinical results obtained with low magnetic field equipment].

Magnetic Resonance Angiography (MRA) is the latest diagnostic technique for the noninvasive evaluation of cardiovascular conditions. This technique has proved to be especially useful in the study of carotid arteries. All the clinical studies reported to date have been obtained at high or medium field strength; our purpose is to assess the clinical value of MRA in the evaluation of carotid arteries at low field strength. All the exams were performed with an 0.2 T permanent magnet, using the 2D time of flight (TOF) technique, the only one which is currently available on our equipment. Forty-two patients with clinical diagnosis of cerebrovascular insufficiency were examined. In all cases MRA findings were confirmed with digital subtraction angiography (DSA), which was considered the gold standard. The double-blind evaluation of the results showed high agreement of the two techniques in 70 of 84 carotid arteries. A mild tendency to overestimation was observed in 4 normal cases considered as mild stenoses on MRA, in 2 cases with mild stenosis considered as discrete stenoses on MRA and in 1 case of severe stenosis considered as an occlusion on MRA. Underestimation was seen in 1 case of mild stenosis considered as normal on MRA, in 2 cases of discrete stenosis which appeared as mild stenoses on MRA and in 2 cases of occlusion considered as severe stenoses. Our study showed high agreement between MRA and DSA results, which means that high quality exams can be obtained even at low field strength. Further progress can be expected when 3D TOF and phase-contrast techniques will be introduced.

Adult↗
PubMed1993

Detection of internal carotid artery stenosis. Comparison of 2D-MR angiography, duplex scanning, and arteriography.

The purpose of this study was to compare digital subtraction angiography (DSA) and duplex scanning with 2D-Magnetic Resonance Angiography (MRA) to evaluate the accuracy of MRA in determining carotid stenosis. All three methods were applied to 101 carotid arteries in 51 patients. Diameter stenosis of the internal carotid artery was categorized as follows: 0 to 39%, 40% to 59%, 60% to 94%, 95% to 99%, and occlusion (100%). All images were read in blind fashion by different physicians. DSA is still considered the "gold standard" investigation. In 78 arteries the degree of stenosis according to MRA correlated exactly with that of conventional angiography. In the remaining 23, carotid arteries MRA upgraded the stenosis in 13 and downgraded it in 8. The principal problem is the overestimation of the lesion, which was particularly revealing in lesions of more than 60%. Furthermore to date MRA is not able to evaluate the presence of ulceration. For this reason 2D-MRA alone is not a reliable method for evaluating the presence of carotid artery stenosis.

Angiography, Digital Subtraction↗
PubMed1993

Magnetic resonance angiography: current clinical applications.

Magnetic Resonance Angiography (MRA) is the newest non-invasive procedure for the evaluation of the vascular system. The basis to obtain images of vessels from Magnetic Resonance (MR) data rely upon the specific signal alteration determined by flowing blood. By using special techniques only these signals are evidenced, with cancelling of the surrounding stationary tissues. Clinical applications are reviewed in this paper. They include: Evaluation of intracranial vessels with important adjunct information to those obtained by conventional MR images; Definition of cerebrovascular disease including the carotid artery with good correlation with Digital Subtraction Angiography (DSA); Evidence of abdominal vessels, with clear imaging of abdominal aortic aneurysms; Definition of renal arteries; although problems exist, the technique may become useful in the future for the screening of renovascular hypertension; Visualization of peripheral vessels; initial results indicate a potential application in the evaluation of peripheral run-off distal to occlusions.

Carotid Artery Diseases↗
PubMed1992

Carotid arteries: evaluation with low-field-strength MR angiography.

Magnetic resonance (MR) angiography of neck vessels was performed with a 0.2-T permanent magnet by using a two-dimensional, time-of-flight technique. Thirty-one patients were included in the study. The imaging parameters used included a repetition time of 60 msec, an echo time of 10 msec, a 90 degrees flip angle, and a 192 x 256 matrix; 40-50 sequential two-dimensional sections were acquired through the neck. Stenosis was graded on a scale of 1-5. Correlation of digital and MR angiography was made in the clinically nonrelevant cases (stenoses of grades 1 and 2), with overestimation to grade 3 in six cases. Two grade 3 stenoses were overestimated as grade 4. Severe stenoses were correctly characterized in all but one case, which was underestimated because of a segmental short extension of the stenotic lesion. Obstructions were found in two cases. Areas with a lack of signal were observed in four patients with severe stenosis and in two with tortuous arteries. Correct diagnosis, however, was achieved with analysis of the maximum intensity projection animation display. Low-field-strength MR angiography has the same clinical value as that performed with high field strengths.

Adult↗
PubMed1992

Arteriography in diagnosing hepatocellular carcinoma.

The diagnostic role of arteriography in the evaluation of hepatocellular carcinoma is pointed out. In the identification of large lesions angiography achieves a sensitivity of 100%. However, when evaluating small lesions (under 5 or 3 cm in diameter), the sensitivity is reported to be 82-89%. To increase the sensitivity, different special techniques have been developed which require angiographic placement of a catheter. These include CT arteriography, CT arterial portography and CT after intraarterial injection of iodized oil. Particularly with the two latter techniques, the sensitivity in identification of small hepatocellular carcinoma reaches a value of 91-95%. Angiography can also be proposed for the characterization of neoplastic lesions in cirrhotic livers. Its specificity is 72% in the differential diagnosis of hepatocellular carcinoma and adenomatous hyperplastic nodules. Small grade I hepatocellular carcinoma can simulate this benign lesion at angiography, as well as at histology. Finally, angiography may still play a role in the preoperative staging of hepatocellular carcinoma both for the diagnosis of satellite lesions and for the identification of vascular invasion.

Angiography↗
PubMed1991

Evaluation of hematoma by MRI in follow-up of aorto-femoral bypass.

We selected a population of 20 patients with atherosclerotic disease, submitted to implantation of aorto-femoral bypass graft. These patients were studied by MRI with T1- and T2-weighted sequences (w.s.) using a 0.5 T superconductive magnet. Investigation was performed at 1 wk, 1, 3, and 6 mo after dacron implantation, to evaluate the normal evolution of hematoma and the potential development of complications. At the first week examination, hematoma presented medium signal intensity on T1 w.s. and high signal intensity on T2 w.s.; at 1 mo control the amount of hematoma was slightly reduced and we found persistence of high signal intensity on T2 w.s.; progressive reduction of size and signal intensity on T2 w.s. was noted at 3 mo control, in patients operated for peripheral vascular disease; on the other hand we found persistence of high signal intensity in T2 w.s. in patients treated for abdominal aortic aneurysms; only after 6 mo it was evident in all patients fibrotic evolution of the collection and low signal intensity in both T1 and T2 w.s. Thus, MRI study was useful in the evaluation of patency, morphology, and in detection of intraluminal thrombosis, but also in the characterization of periprosthetic hematoma.

Aged↗
PubMed1990

Abdominal aortic aneurysm evaluation: comparison of US, CT, MRI, and angiography.

We studied 26 cases of abdominal aortic aneurysm with magnetic resonance imaging (MRI), computed tomography (CT), ultrasonography (US), and angiography. Data acquired were compared to those obtained at surgery. Diameter of the aneurysm was correctly defined in all cases by CT and MRI, while angiography underestimated the diameter of lesions without peripheral calcifications. Involvement of renal arteries was present in four cases and correctly diagnosed with MRI and angiography in all of them. CT did provide this information in three cases and US were not useful. Also, iliac arteries involvement was depicted by CT, MRI, and angiography in 10 out of 10 patients. Coronal sections of MRI provided comparable images to those of angiography. By comparing these different techniques we verified the good reliability of MRI as investigation tool for an accurate evaluation of aneurysms; its only limit lying in the poor capability of detecting calcifications.

Aged↗
PubMed1982

Novel rifamycins. I-Synthesis and antibacterial activity of 3-hydrazinorifamycin derivatives.

A number of semisynthetic rifamycin derivatives, modified at position 3, belonging to general structures (II), (III), (IV), (V), (VI), (VII) and (VIII) (see Scheme), have been prepared. The synthesis, structure, and antimicrobial evaluation of the new compounds are described. All the derivatives have in vitro antibacterial activities comparable with that of rifampicin.

Bacteria↗