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Biomedical subjects

A Masotti

Publications and source records attributed to A Masotti.

At least 19 recordsLinked to original sources
PubMed2001

Exploring the photocatalytic properties and the long-lifetime chemosensor ability of Cl(2)[Ru(Bpy)(2)L] (L = 2,5,8,11,14-pentaaza[15])-2,2'-bipyridilophane).

In this work a new water-soluble long-lifetime chemosensor, containing a polyamine unit connected to a complexed Ru(II) metal center, is described. Its crystal structure has been characterized by X-ray analysis. The polyamine macrocyclic unit is capable of anchoring cationic or anionic substrates, according to its protonation state. Examples of electron transfer involving the ruthenium complex core and the bound substrate are presented. The photocatalytic ability of such a system is illustrated by the oxidation of iodide to iodine promoted by light absorption at 436 nm.

Journal Article↗
PubMed2001

Protonation and Zn(II) coordination by dipyridine-containing macrocycles with different molecular architecture. A case of pH-controlled metal jumping outside-inside the macrocyclic cavity.

The synthesis of the macrocyclic ligand 4,4'-(2,5,8,11,14-pentaaza[15])-2,2'-bipyridylophane (L3), which contains a pentaamine chain linking the 4,4'-positions of a 2,2'-dipyridine moiety, is reported. Protonation and Zn(II) complexation by L3 and by macrocycle L2, containing the same pentaamine chain connecting the 6,6'-positions of 2,2'-dipyridine, were studied by means of potentiometric, UV-vis, and fluorescent emission measurements. While in L2 all the nitrogen donor atoms are convergent inside the macrocyclic cavity, in L3 the heteroaromatic nitrogen atoms are located outside. Both ligands form mono- and dinuclear Zn(II) complexes in aqueous solution. In the mononuclear Zn(II) complexes with L2, the metal is coordinated inside the macrocyclic cavity, bound to the heteroaromatic nitrogen donors and three amine groups of the aliphatic chain. As shown by the crystal structure of the [ZnL2](2+) complex, the two benzylic nitrogens are not coordinated and facile protonation of the complex takes place at slightly acidic pH values. Considering the mononuclear [ZnL3](2+) complex, the metal is encapsulated inside the cavity, not coordinated by the dipyridine unit. Protonation of the complex occurs on the aliphatic polyamine chain and gives rise to translocation of the metal outside the cavity, bound to the heteroaromatic nitrogens.

Journal Article↗
PubMed2001

Arrhythmogenic right ventricular dysplasia: cardiomyopathy current opinions on diagnostic and therapeutic aspects.

Right Ventricular Dysplasia constitutes a genetic cardiomyopathy characterized by fibrous-adipose substitution of the right and rarely of the left ventricular myocardium. This disorder is associated with ventricular arrhythmias ranging from frequent ventricular ectopic beats, nonsustained and sustained ventricular tachycardia of left bundle branch morphology and sudden death. Therefore, the syndrome has been labelled Arrhythmogenic RVD Cardiomyopathy. Diagnostic criteria, preliminary genetic data, and clinical manifestations are summarized and critical addressed, using data from the literature and from our own experience. The most important aspects of the ECG in this syndrome are reviewed and stressed with particular attention to initial versus advanced clinical subsets. The typical anatomical abnormalities and biopsy or pathology material are presented.

Arrhythmogenic Right Ventricular Dysplasia↗
PubMed1999

Identification of domains responsible for von Willebrand factor type VI collagen interaction mediating platelet adhesion under high flow.

We have identified type VI collagen (Col VI) as a primary subendothelial extracellular matrix component responsible for von Willebrand factor (vWF)-dependent platelet adhesion and aggregation under high tensile strength. Intact tetrameric Col VI was the form of the collagen found to be capable of promoting vWF-mediated platelet adhesion/aggregation under this shear condition, whereas removal of the predominant portion of the terminal globules by pepsin treatment abrogated its activity. The inability of the pepsin-digested Col VI to support any platelet interaction at high flow was because of the failure of the A3(vWF) domain to bind to this form of collagen, suggesting a stringent requirement of a tridimensional conformation or of intactness of its macromolecular structure. In contrast, the A1(vWF) domain bound to both intact and pepsin-digested Col VI tetramers but, in accordance with the cooperating function of the two vWF domains, failed to support platelet adhesion/aggregation under high shear onto Col VI by itself. The putative A1(vWF) binding site resided within the A7(VI) module (residues 413-613) of the globular amino-terminal portion of the alpha3(VI) chain. Soluble recombinant A7(VI) polypeptide strongly perturbed the vWF-mediated platelet adhesion to Col VI under high shear rates, without affecting the binding of the vWF platelet receptor glycoprotein Ibalpha to its cognate ligand A1(vWF). The findings provide evidence for a concerted action of the A1(vWF) and A3(vWF) domains in inducing platelet arrest on Col VI. This is accomplished via an interaction of the A1(vWF) domain with a site contained in the alpha3 chain A7(VI) domain and via a conformation-dependent interaction of the A3(vWF) domain with the intact tetrameric collagen. The data further emphasize that Col VI microfilaments linking the subendothelial basement membrane to the interstitial collagenous network may play a pivotal role in the hemostatic process triggered upon damage of the blood vessel wall.

Animals↗
PubMed1999

Risk of infection associated with microbiological quality of public swimming pools in Bologna, Italy.

Twelve public swimming pools in Bologna (Emilia-Romagna region, Italy) were investigated for the microbiological quality of water and surfaces of the pool edges, showers and changing rooms. At the same time a cross-sectional study was carried out on the health of 238 users (bathers) compared with 238 controls who practised sports other than swimming. Data regarding duration and frequency of exposure, behaviour and recent medical history were gathered by means of a questionnaire. All participants also underwent a medical examination. Compliance of the pool water to the microbiological standards set by Italian regulations was generally good; compliance was total when free chlorine residual was within the recommended limits. However, when analysis was extended to the various surfaces, potentially pathogenic bacteria such as P. aeruginosa and C. albicans were isolated. Eye burning and diarrhoea were the only declared symptoms and verrucas the only diagnosed disease showing statistically significant differences between bathers and controls. Verrucas tended to increase in proportion to exposure. Athlete's foot had a very high prevalence among both bathers (34 %) and controls (27.3%) and controls (27%). The environmental and epidemiological investigations both confirmed the risk of infection, mainly associated with the contamination of surfaces.

Bacterial Infections↗
PubMed1999

Gemcitabine and cisplatin versus mitomycin, ifosfamide, and cisplatin in advanced non-small-cell lung cancer: A randomized phase III study of the Italian Lung Cancer Project.

PURPOSE: To compare gemcitabine and cisplatin (GC) with mitomycin, ifosfamide, and cisplatin (MIC) chemotherapy in patients with stage IIIB (limited to T4 for pleural effusion and N3 for supraclavicular lymph nodes) or stage IV non-small-cell lung cancer (NSCLC). The end points were the evaluation of quality of life (QoL), response rates, survival, and toxicity. PATIENTS AND METHODS: Three hundred seven patients were randomized to receive either gemcitabine 1,000 mg/m(2) on days 1, 8, and 15 plus cisplatin 100 mg/m(2) on day 2, every 28 days, or mitomycin 6 mg/m(2), ifosfamide 3,000 mg/m(2), and mesna on day 1 plus cisplatin 100 mg/m(2) on day 2, every 28 days. The whole-blood cell count was repeated on day 1 in both arms and weekly in the GC arm before each gemcitabine administration. RESULTS: No major differences in changes in QoL were observed between the two treatment arms. The objective response rate was 38% in the GC arm compared with 26% in the MIC arm (P =.029). The median survival time was 8.6 months in the GC arm and 9.6 months in the MIC arm (P =.877, log-rank test). Grade 3 and 4 thrombocytopenia was significantly worse in the GC arm (64% v 28%, P <.001), whereas grade 3 and 4 alopecia was reported more commonly in the MIC arm (39% v 12%, P <. 001). CONCLUSION: We report an increased response rate without changes in QoL and a similar overall survival, time to progression, and time to treatment failure for the GC when compared with the MIC regimen in the treatment of advanced NSCLC.

Adult↗
PubMed1998

Characterization of the initial alpha-thrombin interaction with glycoprotein Ib alpha in relation to platelet activation.

We have evaluated the properties of alpha-thrombin interaction with platelets within 1 min from exposure to the agonist, a time frame during which most induced activation responses are initiated and completed. Binding at 37 degrees C was rapidly reversible and completely blocked by a monoclonal antibody, LJ-Ib10, previously shown to be directed against the alpha-thrombin interaction site on glycoprotein (GP) Ib alpha. By 2-5 min, however, binding was no longer fully reversible and was only partially inhibited by the anti-GP Ib alpha antibody. Results were similar at room temperature (22-25 degrees C), whereas the initial characteristics of alpha-thrombin interaction with platelets were preserved for at least 20 min at 4 degrees C. Equilibrium binding isotherms obtained at the latter temperature were compatible with a two-site model, but the component ascribed to GP Ib alpha, completely inhibited by LJ-Ib10, had "moderate" affinity (kd on the order of 10(-8) M) and relatively high capacity, rather than "high" affinity (kd on the order of 10(-10) M) and low capacity as currently thought. The parameters of alpha-thrombin binding to intact GP Ib alpha on platelets at 4 degrees C corresponded closely to those measured with isolated GP Ib alpha fragments regardless of temperature. Blocking the alpha-thrombin-GP Ib alpha interaction caused partial inhibition of ATP release and prevented the association with platelets of measurable proteolytic activity. These results support the concept that GP Ib alpha contributes to the thrombogenic potential of alpha-thrombin.

Adenosine Triphosphate↗
PubMed1998

Phase-II randomized study of pre-operative IL-2 administration in operable NSCLC.

Lymphocytopenia is a prognostic factor for shorter survival in advanced lung cancer and it is likely related to an interleukin-2 (IL-2) deficiency occurring during cancer progression. Major surgery itself for cancer is known to induce lymphocytopenia in the postoperative period. Postoperative lymphocyte decrease in colorectal cancer can be prevented by preoperative administration of recombinant human (rhIL-2), indicating that it is possible to drive appropriately important host defence agents during critical events, such as major surgery. The aim of this study is to verify if recombinant human interleukin-2 (rhIL-2) administered preoperatively is able to prevent the lymphocyte decrease occurring after radical surgery in operable lung cancer. This phase II study included 40 patients with operable NSCLC screened as stage II or IIIA, randomized to receive rhIL-2, 9000000 IU subcutaneously twice daily for 3 days before surgery (treated group, 20 patients) or not (control group, 20 patients). At baseline, there were no significant differences in total lymphocyte number and lymphocyte subsets (T-cell, T-helper, CD8+, natural killer, CD4/CD8 ratio) between groups. Postoperatively the control group showed a decrease in total lymphocyte count, T-lymphocyte count, T-helper cell number and CD4/CD8 ratio, significant at the 14th postoperative day relative to baseline values. In contrast, in the rhIL-2 treated group, at the 3rd and at the 14th postoperative days, a significant increase was observed over both baseline and control group values of total lymphocyte count, T-cells and T-helper cells. NK cell number increased significantly only over the control group. CD4/CD8 ratio was increased at the 14th postoperative day significantly over both baseline and control values. At pathological staging after surgery, four patients in the rhIL-2 group and four in the control group resulted in stage pIIIB; one patient in the rhIL-2 group resulted in stage IV (contralateral metastasis). Indeed, 15/20 rhIL-2 treated patients and 16/20 control patients were radically operated. After a 24-month follow-up, 12/20 rhIL-2 treated patients were alive and 8/15 radically operated were disease-free; 8/20 control patients were alive and 4/16 radically operated were disease-free. Toxicity was mild to moderate and easy manageable; treatment was suspended in one patient due to skin rash with hypotension grade II. The preoperative administration of rhIL-2 is feasible and prevents lymphocyte decrease occurring postoperatively after surgery for lung cancer. Further studies are required to assess the impact on survival.

Adult↗
PubMed1998

Positive immunostaining with MLuC1 of bone marrow aspirate predicts poor outcome in patients with small-cell lung cancer.

BACKGROUND: Immunocytochemistry has been proven able to identify tumor cells in bone marrow aspirate (BMA) of patients with SCLC. However, few data exist about the clinical significance of the procedure. PATIENTS AND METHODS: 108 BMA taken from 60 patients were incubated with the MoAb MLuC1 (cluster 6) and stained by the APAAP (alkaline phosphatase-antialkaline phosphatase) method. The serum levels of LDH, TPA, NSE and CEA were also studied in relation to bone marrow involvement by means of discriminant analysis. RESULTS: Immunocytochemistry of the aspirate with MLuC1 detected positive cells in 23 patients (38%) (38 of 108 samples) vs. 13% of the conventional biopsies studied without MLuC1 (P < 0.001). With respect to bone marrow positivity, three groups of patients were identified: those with no positive cells in the aspirate and negative biopsy (group A); those with less than 10 positive cells in the aspirate and negative biopsy (group B); and those with more than 10 positive cells or clumps in the aspirate or positive biopsy (group C). Group C patients had poorer median survivals than those in the other two groups (5.5 vs. 11 months, respectively, P = 0.01). Discriminant analysis showed that the four serum markers were poor discriminators of the degree of bone marrow involvement, with only 55% of grouped cases being correctly classified. CONCLUSIONS: These results show that detection of bone marrow involvement i) can be improved by the use of MLuC1 ii) is not predictable by conventional tumor markers, and iii) is related to poor outcome.

Antibodies, Monoclonal↗
PubMed1997

Intrapleural administration of recombinant interleukin-2 in non-small cell lung cancer with neoplastic pleural effusion.

The aim of this study was to assess the feasibility and effectiveness of intrapleural administration of recombinant human interleukin-2 (rhIL-2) for treatment of malignant pleural effusions. From May 1993 to May 1995, 21 patients with non-small cell lung cancer (NSCLC) and cytologically documented malignant pleural effusion entered the study. After complete needle drainage of the effusion, a dose of 9 x 10(6) international units (IU) rhIL-2 was injected intracavitarily. The drug was injected on the first and second day each week for 3 weeks, in relation to the presence of effusion. Complete response (according to the criteria reported by Paladine st al.) was achieved in 7 of the 21 patients (33%), and partial response in 6 of the 21 patients (29%), with a median duration of 8 months (range 4-10 months). The treatment was well tolerated by all patients. Intracavitary administration of low-dose recombinant human interleukin-2 in malignant pleural effusion due to non-small cell lung cancer is an effective and well tolerated therapeutic strategy.

Adenocarcinoma↗
PubMed1996

More on false thrombocytopenias: EDTA-dependent pseudothrombocytopenia associated with a congenital platelet release defect.

We report herein the case of a 54-year-old woman with a moderate bleeding tendency, diagnosed as an EDTA-dependent pseudothrombocytopenia associated with a congenital platelet release defect. The patient, at the age of 12, had a misleading diagnosis of idiopathic thrombocytopenic purpura and all the recurrent bleeding problems she had during her life were referred to that disease. The recent correct diagnosis of a false thrombocytopenia stimulated further laboratory investigation on the cause of the patient's bleeding tendency with the consequent identification of a congenital platelet deficiency of the arachidonic acid pathway. This finding is of relevant importance for the management of the patient in case of elective surgery or hemorrhagic emergency.

Arachidonic Acid↗
PubMed1996

Porcine von Willebrand factor binding to human platelet GPIb induces transmembrane calcium influx.

Porcine von Willebrand factor (P-vWF) binds to human platelet glycoprotein (GP) Ib and, upon stirring (1500 rpm/min) at 37 degrees C, induces, in a dose-dependent manner, a transmembrane flux of Ca2+ ions and platelet aggregation with an increase in their intracellular concentration. The inhibition of P-vWF binding to GP Ib, obtained with anti GP Ib monoclonal antibody (LJ-Ib1), inhibits the increase of intracellular Ca2+ concentration ([Ca2+]i) and platelet aggregation. This effect is not observed with LJ-Ib10, an anti GP Ib monoclonal antibody which does not inhibit the vWF binding to GP Ib. An anti GP IIb-IIIa monoclonal antibody (LJ-CP8) shown to inhibit the binding of both vWF and fibrinogen to the GP IIb-IIIa complex, had only a slight effect on the [Ca2+]i rise elicited by the addition of P-vWF. No inhibition was also observed with a different anti GP IIb-IIIa monoclonal antibody (LJ-P5), shown to block the binding of vWF and not that of fibrinogen to the GP IIb-IIIa complex. PGE1, apyrase and indomethacin show a minimal effect on [Ca2+]i rise, while EGTA completely blocks it. The GP Ib occupancy by recombinant vWF fragment rvWF445-733 completely inhibits the increase of [Ca2+]i and large aggregates formation. Our results suggest that, in analogy to what is seen with human vWF under high shear stress, the binding of P-vWF to platelet GP Ib, at low shear stress and through the formation of aggregates of an appropriate size, induces a transmembrane flux of Ca2+, independently from platelet cyclooxygenase metabolism, perhaps through a receptor dependent calcium channel. The increase in [Ca2+]i may act as an intracellular message and cause the activation of the GP IIb-IIIa complex.

Animals↗
PubMed1995

Detection at diagnosis of tumor cells in bone marrow aspirates of patients with small-cell lung cancer (SCLC) and clinical correlations.

BACKGROUND: Immunocytochemistry has often been used to identify tumor cells in bone marrow aspirate (BMA) of SCLC patients in order to improve the results of conventional histomorphology. However, whether the detection of bone marrow microlocalisation at diagnosis had implications for prognosis has not been clear. PATIENTS AND METHODS: Eighty-four slides (44 patients) and 66 bone marrow biopsies (from 42/44 patients) were evaluated. Cytospins of BMA were incubated with the monoclonal antibody (MAb) NCC-LU-243, recognising the cluster 1 antigen (NCAM) and then stained by the APAAP (alkaline phosphatase-anti-alkaline phosphatase) method. The relationship among BMA and PS (performance status), NSE (neuron-specific enolase), stage, survival was also studied. RESULTS: 33/84 (39%) BMA were positive for NCAM, compared with 8/66 (12%) bone marrow biopsies (p = 0.009), (17/44 and 6/42 patients, respectively). Moreover, BMA was positive for NCAM in 6/19 patients with limited disease. The presence of positive BMA did not correlate with PS, NSE or stage, but patients with positive BMA had shorter survivals than those with negative BMA (median survival: 7 and 12 months, respectively, p = 0.007). CONCLUSIONS: Bone marrow involvement detected by immunocytochemistry appears to be related to survival but not to parameters of tumor burden (NSE, stage), suggesting that this technique might help to select patients with better prognoses for new therapeutic strategies.

Antigens, CD↗
PubMed1995

Clinical and bronchoscopic features of endobronchial tuberculosis.

Clinical and bronchoscopic features of endobronchial tuberculosis were retrospectively investigated in 24 patients. A barking cough was the most frequent chief complaint in 50% of patients. The typical apico-subclavian localization of pulmonary tuberculosis in adults was found in only 50% of patients; in one patient the lung fields were clear. Bronchoscopic features consisted of exudative lesions in 38% of cases, ulcerative lesions in 25%, granulomatous lesions in 25%, and ulcerative-granulomatous tumour-like lesions in 12%. In 12% of patients, a residual fibrotic stenosis was seen. It was concluded from our data that patients whose cough is barking and resistant to antitussive agents should be evaluated for endobronchial tuberculosis, and, therefore, the use of fibreoptic bronchoscopy is mandatory. We also conclude that diagnosis of endobronchial tuberculosis demands the use of corticosteroid therapy.

Adult↗
PubMed1994

Localization and characterization of an alpha-thrombin-binding site on platelet glycoprotein Ib alpha.

Glycoprotein (GP) Ib alpha is required for expression of the highest affinity alpha-thrombin-binding site on platelets, possibly contributing to platelet activation through a pathway involving cleavage of a specific receptor. This function may be important for the initiation of hemostasis and may also play a role in the development of pathological vascular occlusion. We have now identified a discrete sequence in the extracytoplasmic domain of GP Ib alpha, including residues 271-284 of the mature protein, which appears to be part of the high affinity alpha-thrombin-binding site. Synthetic peptidyl mimetics of this sequence inhibit alpha-thrombin binding to GP Ib as well as platelet activation and aggregation induced by subnanomolar concentrations of the agonist; they also inhibit alpha-thrombin binding to purified glycocalicin, the isolated extracytoplasmic portion of GP Ib alpha. The inhibitory peptides interfere with the clotting of fibrinogen by alpha-thrombin but not with the amidolytic activity of the enzyme on a small synthetic substrate, a finding compatible with the concept that the identified GP Ib alpha sequence interacts with the anion-binding exosite of alpha-thrombin but not with its active proteolytic site. The crucial structural elements of this sequence necessary for thrombin binding appear to be a cluster of negatively charged residues as well as three tyrosine residues that, in the native protein, may be sulfated. GP Ib alpha has no significant overall sequence homology with the thrombin inhibitor, hirudin, nor with the specific thrombin receptor on platelets; all three molecules, however, possess a distinct region rich in negatively charged residues that appear to be involved in thrombin binding. This may represent a case of convergent evolution of unrelated proteins for high affinity interaction with the same ligand.

Adenosine Triphosphate↗
PubMed1994

Acute respiratory failure.

Respiratory failure is a severe impairment of pulmonary gas exchange, consequence of lung failure leading to hypoxaemia and/or pump failure causing hypercapnia. Acute respiratory failure (acute lung injury and asthma) or acute on chronic respiratory failure (COPD and chest wall disorders) are the two terms proposed to characterize different onset and development. Mechanical ventilation, is often a necessary life-saving treatment in many critically ill patients, it is associated with complications such as infection or barotrauma. Other innovative techniques are mask ventilation and proportional assist ventilation (PAV). The major aim of mask ventilation is to prevent complications related to tracheal intubation, particularly respiratory tract infections and barotrauma.

Acute Disease↗