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Biomedical subjects

M Di Muzio

Publications and source records attributed to M Di Muzio.

At least 19 recordsLinked to original sources
PubMed2000

Prognostic significance of presence and reduplication of basal lamina in malignant pleural mesothelioma.

The prognosis of patients with malignant pleural mesothelioma (MM) is dependent more on tumor extension and differentiation than on therapeutic effects. Reduplication of the basal lamina (RBL) is an ultrastructural feature of some benign and malignant tumors that has been inversely correlated with aggressiveness and was recently described in MM. To investigate whether RBL is important for predicting the survival of patients with MM, transmission electron microscopy was used to identify the presence of basal lamina or RBL in biopsy specimens obtained by thoracoscopy from 35 patients. Cox's regression analysis was used to study the relation of these ultrastructural features to survival. Better outcomes were found for patients whose tumors expressed either basal lamina (HR 0.48; 95% CI, 0.09-2.47) or RBL (HR 0.38; 95% CI 0.12-1.22) compared with the reference category, where basal lamina or RBL was not found. The expression of basal lamina and RBL is an important novel prognostic factors in MM. HUM PATHOL 31:1341-1345.

Aged↗
PubMed1999

Modulation of integrin expression on mesotheliomas: the role of different histotypes in invasiveness.

The in vitro and in vivo integrin expression in human pleural malignant mesothelioma (MM) of three different histotypes was studied. Cell lines from MM of epithelioid (E1), fibrous (F1), byphasic histotype (B1) and normal mesothelial cells (NM) were analysed for the surface expression of alpha2, alpha3, alpha4, alpha5, alpha6, alphav, beta1, beta3, beta4 subunits and alphavbeta5 integrins. We found that alpha6, beta4 subunits and alphavbeta5, weakly detectable on NM cells, were expressed on MM cells. The beta3 subunit, well expressed on NM cells, was absent on MM cells. Differential expression among histotypes was observed, the MM-E1 was the least and the MM-B1 the most positive. Specimens for each MM histotype, were analysed by immunohistochemistry. The alpha6 and alphav subunits were more evident on the epithelioid histotype. Intense staining for beta3 and beta4 subunits, was found in all MM, particularly in invading cells, while the alpha5, and alphavbeta5 integrins were variously expressed. The different histotypes can affect the in vitro integrin expression and may indicate a preferential involvement of some subunits in vivo during MM tumor progression.

Humans↗
PubMed1999

[The effects of verapamil on the postischemic changes in the coronary microcirculation: the role of nitric oxide].

BACKGROUND: The aim of this study was to evaluate, in the model of isolated working rat heart, the effects of verapamil on postischemic changes in cardiac mechanical function and microvascular coronary permeability, and the possible role of nitric oxide. METHODS: We used 72 male Wistar rats, weighing 250-300 g, divided into six groups: Group A, hearts perfused with modified Krebs-Henseleit solution (KH); Group B, hearts perfused with KH + verapamil 0.25 microM; Group C, hearts perfused with KH + verapamil 0.5 microM; Group D, hearts perfused with KH + verapamil 1 microM; Group E, hearts perfused with KH + NG-nitro-L-arginine methyl ester (L-NAME) 30 microM; Group F, hearts perfused with KH + verapamil 0.25 microM + L-NAME 30 microM. Hemodynamic parameters, necrosis enzyme release and fluoroscein isothiocyanate-albumin extravasation were evaluated. RESULTS: We observed a clear preservation of cardiac mechanical function and microvascular function in Group B (low dose verapamil) compared to groups A (control), C and D (high dose verapamil); the inhibition of nitric oxide-synthase in the presence of verapamil, obtained in Group F, elicited a loss of myocardial protective effects of verapamil. CONCLUSIONS: Our data suggest that low dose verapamil is effective on postischemic damage reduction and most probably nitric oxide plays a determinant role in this effect.

Animals↗
PubMed1998

Effect of chronic hyperoxia on young and old rat carotid body ultrastructure.

Morphologic, physiological, and biochemical changes occur in the carotid body (CB) during postnatal development in relation to physiological requirements. Chronic normobaric hyperoxia attenuates the carotid chemosensory response to hypoxia. During aging there is less of a CB response to hypoxia, which results in a reduced ventilatory adaptation and chemosensory discharge. To test if the oxygen-sensitive mechanism is affected by chronic hyperoxia in an age-dependent fashion, we have studied structural and ultrastructural aspects of young and old rat CBs. Four groups of six male Wistar rats were used. One group of two-month-old rats and another of 25-month-old rats were kept at room air. The other two groups, age matched, were exposed to 98-100% O2, for 60-65 h, in a large Plexiglas chamber. The rats were anesthetized, CBs were fixed in situ with glutaraldehyde (2.5% in phosphate buffer. pH 7.4, 320 mOsm), and were prepared for electron microscopy. Young hyperoxic rats showed focal necrosis in type I cells, along with an increase of endoplasmic reticulum, Golgi apparatus, and of mitochondria volume, with loss of cristae. These changes were less pronounced in the older rat CBs compared with the young rats. In conclusion, hyperoxia seems to affect the oxygen-sensitive mechanism in the carotid body cells, and the reduced effects shown in the old rat CBs suggest an age-related decreased sensitivity to oxygen.

Aging↗
PubMed1998

'Suction split' as a routine method to differentiate epidermolysis bullosa acquisita from bullous pemphigoid.

BACKGROUND AND DESIGN: Epidermolysis bullosa acquisita (EBA) and bullous pemphigoid (BP) are diseases with similar clinical, histological, and immunofluorescent findings. Diagnosis requires the use of immunoelectron microscopy, immunoprecipitation or immunoblotting, but in recent years the differential diagnosis has been based on a cheaper technique named salt split skin. This study demonstrates that with a suction blister the fracture is at the same level as that obtained with the sodium split method and that it is also faster and cheaper. Suction blisters on normal skin and autoimmune perilesional bullous lesions, obtained with a hand vacuum pump, were studied by direct immunofluorescence and electron microscopy to evaluate the level of the split on normal suction split skin. Normal human split skin was also used as a substrate for an indirect immunofluorescent study using sera of patients with BP (68 sera), EBA (10 sera) and cicatricial pemphigoid (CP) (16 sera). Direct immunofluorescent examination was also done on perilesional skin after artificial separation obtained with a hand-vacuum pump in patients with the same diseases listed above (32 BP, 11 CP, 6 EBA). RESULTS: On normal human skin split by suction or sodium chloride (NaCl; 1 mol/l) direct immunofluorescence and electron microscopy demonstrated that the split is at the lamina lucida level. Indirect immunofluorescent study of both normal human skin and perilesional skin split using suction as a substrate showed IgG deposits localized on the floor of the suction blister in all cases of EBA, whereas in over 88% of cases of BP and in over 62% of CP the IgG were localized on the roof. Similar results were obtained with direct immunofluorescence in perilesional skin. CONCLUSIONS: 'Suction split' represents a simple technique to differentiate EBA from BP. This method provides final response in a few hours compared to at least 1-2 days with the sodium split method. Furthermore, the suction split method is cheaper and the tissue can be re-utilized for molecular biology and immunohistochemical studies.

Diagnosis, Differential↗
PubMed1998

[Effect of A1 adenosine receptor blockade on postischemic damage to the coronary microcirculation].

Recent studies suggest that A1 adenosine receptor antagonists may prevent reperfusion injury in the lung and heart. The pathophysiology of this protective effect is unclear; a possible inhibition of superoxide anion release from neutrophils, or leukocyte activation and platelet aggregation are reported. We tested the hypothesis of a blood-independent cardioprotection following A1 adenosine receptor antagonism with 1,3 dipropyl,8-cyclopentylxanthine (DPCPX). Isolated working rat hearts were submitted to 10 and 20 min global ischemia in order to assess functional alterations, necrosis enzyme and purine release in coronary effluent, arrhythmias, heart weight, ultrastructural morphometry and microvascular permeability by FITC-albumin diffusion technique. DPCPX (100 nM) was administered to the perfusion buffer before ischemia. In untreated hearts we detected a significant impairment of function, associated with a significant enzyme and purine release, myocardial edema and ultrastructural damage. In DPCPX-treated hearts functional and histological damage was significantly reduced compared to controls. Moreover, a significant reduction in postischemic endothelial permeability (FITC-albumin diffusion, p < 0.02) and ultrastructural damage was observed. Our data suggest that A1 adenosine receptor antagonism with DPCPX significantly reduces ischemia-reperfusion damage in isolated, crystalloid perfused rat heart by a direct reduction of endothelium damage, fluid diffusion within the interstitium and improvement of coronary microcirculation.

Adenosine↗
PubMed1998

Effect of acute increase of interstitial myocardial fluid on ventricular function in isolated working rat hearts.

An acute increase of myocardial interstitial fluid may affect ventricular function. In the present study we evaluated the effects of acute changes of myocardial tissue fluid on cardiac function and ultrastructural morphometry. Isolated rat hearts were perfused for 100 min in the working heart mode. Hearts were distributed into 5 groups: controls [perfused with Krebs-Henseleit (KH) isotonic buffer to rat plasma, KH, 287 mOsm], moderate hyposmotic perfusion (75% Hyposm: perfusion with 75% diluted KH, 216 mOsm), highly hyposmotic perfusion (60% Hyposm: perfusion with 60% diluted KH, 170 mOsm), afterload increase (Pre-over: isotonic perfused hearts subjected to an increase of afterload from 72 to 145 cm H2O) and ion dilution (Ion-dil: hearts perfused with a 60% KH with 115 mM sucrose, isotonic, 287 mOsm). We evaluated functional changes, markers of cellular necrosis or damage (CPK, LDH and purine release in coronary effluent), heart weight changes (weight gain and ww/dw ratio) and ultrastructural morphometry (analysis of cell damage, interstitial area, and mitochondrial alterations by a computerized image analysis system). The ww/dw ratio increased significantly only in 60% Hyposm (+140%, p < 0.001) and Pre-over (+63%, p < 0.001 vs control) groups. An impaired myocardial function in 60% Hyposm, Pre-over and Ion-dil groups was observed with cardiac failure at 50, 60 and 60 min, respectively. Enzyme release was significant higher in 60% Hyposm and Pre-over groups and was related to heart weight gain (r = 0.85, p < 0.001). Ultrastructural analysis confirmed a significant increase of interstitial space area (ISA) and mitochondrial damage in 60% Hyposm and Pre-over groups (p < 0.001); a significant (p < 0.05) increase was observed in the Ion-dil group; in 75% Hyposm group, a significant increase of mitochondrial damage was detected (p < 0.05). In brief, a higher functional and morphological deterioration was observed in hearts in which a more evident interstitial edema was detected (60% Hyposm and Pre-over groups). We conclude that, in the experimental condition, an acute increase of myocardial interstitial tissue fluid directly compromises left ventricular function and contributes to the ultrastructural damage to the myocardium.

Animals↗
PubMed1997

Neuramide inhibits Epstein-Barr virus-induced transformation activity and proliferation of transformed B lymphocytes.

Neuramide, in Italy, is a prescription drug and contains various polypeptides, with molecular weights ranging between 10,000 and 1,000. It is commonly used in Italy for the clinical therapy of varicella-zoster and other viral herpetic diseases. In the present study, we investigated its effect on the in vitro transformation activity and transformed status of the Epstein-Barr virus (EBV), ab herpesvirus closely associated with infectious mononucleosis (IM), nasopharyngeal carcinoma (NPC) and Burkitt's lymphoma (BL). Antiviral effects of neuramide were evaluated on viral-induced immortalization, transformed status and DNA synthesis. Our results show that simultaneous and/or post-treatment of EBV-infected lymphocytes with neuramide, at a concentration of 2 inhibiting units (IU)/ml, blocks EBV-mediated transformation and related events, whereas pretreatment does not show any inhibiting activity against EBV. Neuramide was also found to be a potent inhibitor of the proliferation of EBV-transformed B lymphocytes in vitro. These results suggest that the molecular mechanisms of action of the drug should be investigated more closely and also support the necessity to further purify the active polypeptides, in order to improve its possible in vivo efficacy in EBV-associated diseases, such as infectious mononucleosis and other lymphoproliferative diseases.

Antimicrobial Cationic Peptides↗
PubMed1997

[Ischemic preconditioning of the myocardium: the role of changes in the permeability of the coronary microcirculation].

In isolated working rat hearts we have evaluated the effects of preconditioning on postischemic coronary endothelial permeability. Isolated Wistar male rat hearts were used and subdivided into three groups: Group A, control hearts submitted to 20 min global normothermic ischemia; Group B, hearts subjected, before ischemia, to preconditioning (three phases of 3 min ischemia, each one followed to 2 min Langendorff reperfusion; Group C, hearts submitted to preconditioning and hypertonic reperfusion (by adding 80 mM sucrose to normal perfusion buffer), in order to increase the effects on postischemic interstitial fluid accumulation (osmotic forces balance). A 65 min working heart reperfusion was also performed to assess functional response. We have evaluate the hemodynamic changes (coronary and aortic flows, systolic aortic pressure, work minute), reperfusion arrhythmias, heart weight changes (ww/dw), myocardial enzyme release (creatine phosphokinase and lactic dehydrogenase) and microcirculation permeability changes (FITC.albumin diffusion), as an index of endothelial function. In Group B, a significant reduction of ischemia-reperfusion damage (functional recovery, enzyme release and arrhythmias) was detected with respect to Group A. In Group C this reduction was significantly more evident with respect to groups A and B. In Groups B and C, a significant reduction in myocardial reperfusion (ww/dw: A: 5.9 +/- 0.5, B: 4.9 +/- 1.1, p < 0.02 vs A, C: 4.4 +/- 0.6, p < 0.01 vs A) edema and FITC-albumin diffusion (A: 32.8 +/- 5.9% area; B: 16.3 +/- 6.1% area, p < 0.01 vs A; C: 13.3 +/- 4.5% area, p < 0.01 vs A), especially in perimyocytic space was also observed. Data show that preconditioning may exert a cardioprotective effect by reducing endothelial postischemic functional alterations (vascular permeability) and reperfusion edema. The importance of fluid diffusion within the interstitium in the development of reperfusion damage is supported by better postischemic recovery in Group C, in which an interference on osmotic load was performed.

Animals↗
PubMed1997

[Endothelium-protective effects of epinine (N-methyldopamine) in myocardial ischemia-reperfusion in the isolated working rat heart].

The effect of cardiac dopaminergic receptors stimulation with epinine (N-methyldopamine) on reperfusion injury was investigated in isolated working rat heart submitted to 15 min of global ischemia. Isolated Wistar rat hearts (n = 75) were used and subdivided into five groups: Group A control hearts, Group B epinine 10 ng/ml, Group C epinine 20 ng/ml, Group D epinine 40 ng/ml, Group E epinine 80 ng/ml. The drug was added to the perfusion buffer at the beginning of experimental procedures. Hemodynamic parameters, heart rhythm (epicardial ECG), heart weight changes, coronary microvascular permeability (FITC-albumin diffusion) and myocytes damage (necrosis enzymes release, immunoperoxidase labeling anti-LDH antibody) were evaluated. After ischemia in groups B and C a significant reduction of functional alterations and myocytes damage was observed with respect to Group A associated with a significant reduction of reperfusion edema (heart weight: Group A +29 +/- 3.5%, Group B +15 +/- 3.8%, Group C 16 +/- 5%, Group D 27 +/- 5%, Group E 33 +/- 4%). At reperfusion time, a significant proarrhythmic effect occurred only in groups D and E. A significant reduction of postischemic endothelial FITC-albumin diffusion was also observed in groups B and C (FITC-albumin diffusion, Group A 32.8 +/- 6% area, Group B 16.33 +/- 5% area, Group C 21.7 +/- 4.5% area, Group D 30 +/- 5% area, Group E 35 +/- 7% area). Our data show that, in isolated working rat heart, the dopaminergic stimulation with low-doses epinine may exert a cardioprotective effect against ischemia-reperfusion damage by modulating endothelial permeability changes and improving coronary microcirculation. The importance of dopaminergic receptors is also suggested by the evidence that at higher doses, when alpha and beta-adrenoceptors stimulation occurs, this cardioprotective effect is significantly reduced or lost.

Animals↗