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Biomedical subjects

F Mauri

Publications and source records attributed to F Mauri.

At least 19 recordsLinked to original sources
PubMed2006

Raman spectrum of graphene and graphene layers.

Graphene is the two-dimensional building block for carbon allotropes of every other dimensionality. We show that its electronic structure is captured in its Raman spectrum that clearly evolves with the number of layers. The D peak second order changes in shape, width, and position for an increasing number of layers, reflecting the change in the electron bands via a double resonant Raman process. The G peak slightly down-shifts. This allows unambiguous, high-throughput, nondestructive identification of graphene layers, which is critically lacking in this emerging research area.

Journal Article↗
PubMed2005

Pericardial tamponade as initial presentation of papillary thyroid carcinoma.

We herein describe a 19-year-old woman who presented with pericardial effusion that resulted in heart tamponade. The clinicopathological study revealed papillary carcinoma of the thyroid metastasized to the heart. Although malignant pericardial effusion is a known complication of thyroid cancer, it is rarely the first manifestation and shows a relatively favourable prognosis despite widespread metastases if adequate treatment is given.

Adult↗
PubMed2001

Atomic structure of icosahedral B4C boron carbide from a first principles analysis of NMR spectra.

Density functional theory is demonstrated to reproduce the 13C and 11B NMR chemical shifts of icosahedral boron carbides with sufficient accuracy to extract previously unresolved structural information from experimental NMR spectra. B4C can be viewed as an arrangement of 3-atom linear chains and 12-atom icosahedra. According to our results, all the chains have a CBC structure. Most of the icosahedra have a B11C structure with the C atom placed in a polar site, and a few percent have a B (12) structure or a B10C2 structure with the two C atoms placed in two antipodal polar sites.

Journal Article↗
PubMed2001

Differential expression of transforming growth factors-beta1, -beta2 and -beta3 in human colon carcinoma.

Transforming growth factor (TGF)-beta is a protein family which affects multiple cellular functions including survival, proliferation, differentiation and adhesion. Among the three known isoforms, TGF-beta1 is commonly overexpressed in solid malignancies. Recent studies in knock-out mice demonstrated non-redundant roles of different TGF-beta isoforms in development. The present study was performed to assess tumour-associated expression of the three TGF-beta isoforms in colon carcinoma. We report that colon carcinoma progression is associated with gradual and significant increases in expression of TGF-beta1 and TGF-beta2 mRNA and proteins. By contrast, TGF-beta3 expression was detected in normal colonic mucosa and, at slightly higher levels, in tumour tissues. In addition, plasma levels of both TGF-beta1 and TGF-beta2 were significantly higher in cancer patients when compared with unaffected individuals. Taken together, our results indicate distinct expression patterns of the three TGF-beta isoforms in colon carcinoma cells and possible systemic effects of TGF-beta1 and TGF-beta2 in tumour patients.

Adult↗
PubMed2000

Primary neuroendocrine carcinoma with ganglion cell differentiation in a crural lymph node.

A primary neuroendocrine carcinoma with ganglion cell differentiation is described in a crural lymph node. The patient, a 48-year-old woman, presented a palpable lymph node of the crural region in March 1994. Histologically, the lesion was composed mostly of small cells immunoreactive for cytokeratins, neuron specific enolase and synaptophysin. The small cells merged gradually with areas containing ganglion cells immersed in a fibrillar matrix resembling neuropil. Ganglion cells expressed neuron-specific enolase, synaptophysin, neurofilament proteins and S-100 protein. Moreover, a minority of them featured cytokeratin expression. Electron microscopy was performed in the small cell component. These cells featured attenuated desmosomes and electron dense granules with an average size of 120 nm within bundles of intermediate filaments. Clinically, no tumour was found elsewhere despite extensive work-up over the 76-month follow-up period. Although similarities with previous cases of primary neuroendocrine carcinoma of lymph node, ganglion cell differentiation has never been described.

Carcinoma, Neuroendocrine↗
PubMed2000

Efficacy of rescue thrombolysis in patients with acute myocardial infarction: preliminary findings.

Thrombolysis reduces mortality in patients with acute myocardial infarction (AMI) who are hospitalized within 6 hours from the onset of symptoms. AMIs involving a small area of myocardium show a lower mortality in comparison with AMI involving a large area. The present study was aimed at evaluating the safety and efficacy of rescue thrombolysis in patients with large AMI who had failed thrombolysis. Ninety patients (69 Males and 21 Females), mean age 56.7 +/- 9 years, hospitalized for suspected AMI within 4 hours from the onset of symptoms, suitable for thrombolysis (First episode), and showing pain and persistent ST segment elevation 120 minutes after starting thrombolysis, were randomized (double-blind) into two groups. Group A (45 patients: 10 females and 35 males) received an additional thrombolytic treatment (rTPA 50 mg), 10 mg as bolus plus 40 mg in 60 minutes. Group B (45 patients: 11 females and 34 males) received placebo. Positive noninvasive markers were defined as follows: (1) resolution of chest pain, (2) > or = 50% reduction in ST segment elevation, (3) double marker of creatine kinase (CK) and CK-MB activity 2 hours after the start of thrombolysis, and (4) occurrence of reperfusion arrhythmias within the first 120 minutes of thrombolytic therapy. Blood pressure, heart rate, and ECG were continuously monitored. An echocardiogram was carried out at entry, and before discharge, to control ejection fraction and segmentary kinetics. Adverse events such as death, re-AMI, recurrent angina, incidence of major and minor bleeding, and emergency CABG/PTCA were checked. The groups were similar in terms of age, sex, diabetes, smoking habits, hypertension, and adjuvant therapy (beta-blockers). No significant difference was observed between the two groups regarding the time elapsed from the onset of symptoms to thrombolysis and AMI localization. Thirty-five patients (77.7%) showed reperfusion (10-50 minutes) after commencement of additional rTPA. Of the patients receiving placebo, 12 (26.6%) showed reperfusion within 35-85 minutes. Group A showed an earlier and lower CK and CK-MB peak than the control group, (respectively, p = 0.0001-0.009 and 0.002). Mortality (17.7%, 16 patients) was higher in group B than in the additional rTPA group, i.e., 6.6% (3 patients) in group A versus 28.8% (13 patients) in Group B (p = 0.041). Seven patients from group A showed nonfatal re-AMI. Angina was observed in 18 patients (40%) from group A and 3 (6.6%) from group B (p = 0.006). Ten of these patients underwent urgent PTCA (9 from group A and 1 from group B), and 3 from group A underwent urgent CABG. Minor bleeding was higher in group A than in group B (44.4% versus 15.5%, p = 0.047). Major bleeding was observed in group A (nonfatal stroke). At predischarge, the echocardiogram ejection fraction was higher in group A than in group B (46 +/- 8% versus 38 +/- 7%, p = 0.0001). Our data suggest that an additional dose of thrombolytic drug in patients with unsuccessful thrombolysis is feasible and also that the bleeding increase is an acceptable risk in comparison with the advantages obtained in reducing AMI extension. Rescue thrombolysis can allow a gain in time to perform mechanical revascularization in patients admitted to hospital without an interventionist cardiology laboratory or in those who have to be referred to another hospital for urgent CABG.

Acute Disease↗
PubMed2000

[The safety and efficacy of systemic salvage thrombolysis in acute myocardial infarct].

BACKGROUND: Thrombolysis reduces mortality in patients with acute myocardial infarction hospitalized within 6 hours of the symptom onset. Infarctions involving a small area of the myocardium show a lower mortality in comparison to those involving a large area. The aim of this study was to evaluate the safety and efficacy of rescue thrombolysis in patients with large acute myocardial infarction who had failed standard thrombolysis. METHODS: From January 1995 to December 1997, ninety patients (69 males, 21 females, mean age 56.7 +/- 9 years), hospitalized for suspected acute myocardial infarction within 4 hours of the symptom onset, suitable for thrombolysis (first episode), and who experienced pain and showed persistent ST segment elevation 120 min after starting thrombolysis, were randomized (single blind) into two groups: Group A (n = 45) received an additional thrombolytic treatment (rt-PA 50 mg), 10 mg as a bolus plus 40 mg in 60 min; Group B (n = 45) received conventional therapy. Positive non-invasive markers were defined as follows: resolution of chest pain; > 50% reduction in ST segment elevation; double marker of creatine phosphokinase (CPK) and CK-MB activity 2 hours after the start of thrombolysis; occurrence of reperfusion arrhythmias within the first 120 min of thrombolytic therapy. Blood pressure, heart rate and ECG were continuously monitored. Echocardiogram was carried out at entry and before discharge to control ejection fraction and segmental wall motion. Adverse events such as death, reinfarction, recurrent angina, incidence of major and minor bleeding, and emergency bypass surgery or coronary angioplasty were checked. RESULTS: Thirty-five patients (77.7%) showed reperfusion (10-50 min) after the start of additional rt-PA. In patients who did not receive additional thrombolysis, only 12 (26.6%) showed reperfusion 65-115 min after the end of rt-PA infusion. Group A showed an earlier and lower CK and CK-MB peak than Group B (p = 0.0001, p = 0.009, and p = 0.002, respectively). Mortality (n = 16, 17.7%) was higher in Group B (n = 13) than in Group A (n = 3) (28.8 vs 6.6%, p = 0.041). Seven patients from Group A showed non-fatal reinfarction. Angina was observed in 18 (40%) patients from Group A and 3 (6.6%) from Group B (p = 0.006). Ten of these patients underwent urgent coronary angioplasty (9 from Group A and 1 from Group B) and 3 from Group A urgent bypass surgery. Minor bleeding was higher in Group A than in Group B (44.4 vs 15.5%, p = 0.047). A major bleeding was observed in Group A (non-fatal stroke). At predischarge echocardiogram ejection fraction was higher in Group A than in Group B (46 +/- 8 vs 38 +/- 7%, p = 0.0001). CONCLUSIONS: Our data suggest that an additional dose of a thrombolytic drug in patients with unsuccessful thrombolysis is feasible, and the bleeding increase is an acceptable risk in comparison with the advantages obtained from a reduced infarct extension. Rescue thrombolysis could save time and allow mechanical revascularization to be carried out in patients admitted to a hospital without interventional cardiology laboratory or in those who have to be refereed to other hospitals for urgent bypass surgery.

Aged↗
PubMed1999

Intermittent 6-month low-dose dobutamine infusion in severe heart failure: DICE multicenter trial.

BACKGROUND: Patients with end-stage heart failure are often refractory to maximal oral therapy, and they have high mortality rates, poor quality of life, and frequent hospitalizations with elevated health care costs. Intermittent dobutamine therapy has been suggested as an additional option in this clinical setting. METHODS AND RESULTS: Thirty-eight patients clinically stable for at least 48 hours with standard treatment, New York Heart Association (NYHA) functional class III or IV, cardiac index </=2.2 L/min/m(2), and left ventricular ejection fraction </=30% were randomly assigned to ambulatory intermittent dobutamine or optimal standard treatment. Dobutamine was infused at 2.5 microgram/kg/min with a portable pump 48 hours/week for 6 months. The primary study end point was the reduction of hospitalizations for worsening of congestive heart failure (CHF); changes in NYHA functional class, 6-minute walking test, and mortality rates were secondary end points. During the 6-month follow-up, all patients in dobutamine and control groups underwent weekly clinical visits with serum sodium and potassium measurement. Baseline characteristics were age 65 +/- 2 years, NYHA class III/IV 17/21, ejection fraction 22% +/- 1%, and cardiac index 1.89 +/- 0.1 L/min/m(2), without differences between treatment groups. Hospitalizations for all causes over a 6-month period were 17 and 11 in control and dobutamine groups; 11 of 17 and 7 of 11 were for worsening CHF. Four control patients but none in the dobutamine group had 2 or more hospitalizations for worsening of CHF. There were no significant differences in NYHA functional class and in 6-minute walking test. Three patients in the control group died and 5 in the dobutamine group died. Two patients in the dobutamine group underwent heart transplantation. Protocol was discontinued in the dobutamine group for severe ventricular arrhythmias (1 patient), infusion system failure (1 patient), and consent withdrawal (1 patient). In 3 patients in the dobutamine group, drug dose was increased to 5 microgram/kg/min because of CHF. CONCLUSIONS: Six-month intermittent low-dose dobutamine administration was well tolerated by patients with severe CHF; it did not improve the functional status and did not significantly increase the mortality rate as found with higher dobutamine doses in other studies. Hospitalizations for all causes and for worsening of CHF tended to be fewer in the dobutamine group.

Adult↗
PubMed1998

Ten-year follow-up of the first megatrial testing thrombolytic therapy in patients with acute myocardial infarction: results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto-1 study. The GISSI Investigators.

BACKGROUND: We conducted a 10-year follow-up of the 11 712 patients with acute myocardial infarction randomized in the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto-1 study, the first large trial assessing thrombolytic therapy. METHODS AND RESULTS: Information on survival at 10 years was obtained for the 93% of all randomized patients through the census offices of their towns of residence. The difference in survival produced by streptokinase and sustained up to 1 year was still significant at 10 years (log-rank test, P=0.02), with the absolute benefit of 19 (95% CI 1 to 37) lives saved per 1000 patients treated. The time dependence of the extent of the benefit was confirmed, as the higher mortality rate reductions found in patients treated earlier were still present at 10 years. In the overall population, most of the benefit was obtained before hospital discharge (RR 0.81, 95% CI 0.72 to 0.90), since no difference in survival between thrombolyzed and control patients discharged alive was found at 10 years (RR 0.98, 95% CI 0.90 to 1.06). However, a slight albeit nonsignificant divergence of the survival curves of patients randomized within the first hour was observed [90 (95% CI 34 to 146) lives saved per 1000 at 10 years versus 72 (95% CI 37 to 107) lives saved at hospital discharge]. CONCLUSIONS: The benefits of a single intravenous infusion of 1.5 million units of streptokinase in prolonging survival of patients with acute myocardial infarction is sustained up to 10 years, with a still-evident trend in favor of the patients admitted earlier.

Age Factors↗
PubMed1998

Determination of anandamide amidase activity using ultraviolet-active amine derivatives and reverse-phase high-performance liquid chromatography.

Anandamide amidase catalyzes the hydrolysis of anandamide (AEA) to arachidonic acid (AA) and ethanolamine (EA). Recently, we published a method for determining anandamide amidase activity based on the measurement of arachidonic acid with direct UV detection at 204 nm. However, this method cannot be used to determine the hydrolysis of non-UV-active AEA analogs. It also cannot be used to study AEA amidase inhibitors that contain the arachidonic acid tail, and which are also enzyme substrates. Here we report a novel, more general method for measuring amidase activity by o-phthaldialdehyde (OPA) precolumn derivatization and reverse-phase high-performance liquid chromatography (HPLC). The hydrolysis product, ethanolamine, after separation from protein was derivatized with OPA to form a UV-active isoindole derivative which was then detected at 230 nm. The detection limit for derivatized ethanolamine was 1.0 pmol and retention times were typically less than 8 min. Our new method can detect non-UV-active analogs through derivatization of the amine product. It can thus be used after careful selection of the HPLC conditions in competition experiments between AEA and AEA analogs possessing different head groups. The most effective competitive inhibitor tested was (R)-N-(1-methyl-2-hydroxyethyl)arachidonylamide (AM356), which is resistant to enzymatic hydrolysis and yet inhibits AEA hydrolysis in a competition experiment by 43%. Moreover, this method offers several advantages over existing methodologies using radioisotopes or solvent extraction procedures. Our work to date has shown that small structural changes in the AEA molecule can result in significant variation in both affinity and turnover rate for each analog with respect to AEA amidase.

Amidohydrolases↗
PubMed1997

Investigation of physicochemical changes to L-asparaginase during freeze-thaw cycling.

L-Asparaginase derived from Erwinia chrysanthemi which is being investigated as an alternative to E. coli for the treatment of lymphoblastic leukaemia has been found in our laboratory to lose activity upon exposure to consecutive freeze-thaw cycles. An investigation was undertaken using several techniques to characterize fully the physicochemical changes L-Asparaginase is undergoing during freeze-thaw cycling leading to the loss of its activity. A total protein assay suggested that the loss of some enzyme activity was a result of protein precipitation. Circular dichroism (CD) studies showed a decrease of alpha-helical structure with a concomitant increase in beta sheet and random coil content, suggesting alterations in the secondary structure leading to unfolding, the first step of denaturation processes. The elution profiles obtained from size-exclusion chromatography (SEC) studies indicated the formation of several species during the process of freezing and thawing. Sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) studies showed bands corresponding to 1-3 kDa and 32 kDa, suggesting that some of the species are fragments and shortened monomers resulting from cleavage of monomers. The molecular weight distribution obtained using SEC-linked light scattering indicated a substantial fraction of polydispersed fragments ranging from 900 Da to 3 kDa and a small fraction of aggregates corresponding to 300 kDa. A scheme was proposed to explain the cascade of events leading to the loss of soluble protein and accompanying loss of enzyme activity. Tetramers of the enzyme dissociate into monomers some of which are cleaved into small fragments. The shortened monomers then aggregate and precipitate.

Asparaginase↗
PubMed1997

Expert pathology consultation through the Internet: melanoma versus benign melanocytic tumours.

Twenty consecutive cases of melanocytic lesions were chosen from the archives of the archives of the institute of Anatomic Pathology at Santa Chiara Hospital, Trento. Representative images were acquired at a spatial resolution of 512 x 512 pixels, saved in IPEG format and delivered to the remote pathologist by multimedia internet electronic mail. Six cases were diagnosed as benign melanocytic lesions by the local pathologist. Of the 20 cases transmitted, each with an average of 5.3 images, the remote pathologist suggested a diagnosis of malignancy in nine cases while 10 cases were thought to be benign. In one case the images were not considered sufficient for diagnosis. Overall, the diagnostic agreement between local and remote pathologist was 79% (kappa = 0.58, P = 0.002). This preliminary study suggest that telepathology by internet electronic mail can be a valuable tool for remote consultation in dematopathology, as well as for other diagnostic fields where expert consultation is necessary.

Computer Communication Networks↗