PubMed Health⌕ Search

Biomedical subjects

L Masotti

Publications and source records attributed to L Masotti.

At least 19 recordsLinked to original sources
PubMed2007

A new EGFR inhibitor induces apoptosis in colon cancer cells.

The use of agents targeting EGFR represents a new frontier in colon cancer therapy. Among these, mAbs and EGFR tyrosine kinase inhibitors seemed to be the most promising. However they have demonstrated scarce utility in therapy, the former being effective only at toxic doses, the latter resulting inefficient in colon cancer. This paper presents studies on a new EGFR inhibitor, FR18, a molecule containing the same naphthoquinone core as shikonin, an agent with great anti-tumor potential. In HT29, a human colon carcinoma cell line, flow cytometry, immunoprecipitation, and Western blot analysis, confocal spectral microscopy have demonstrated that FR18 is active at concentrations as low as 10 nM, inhibits EGF binding to EGFR while leaving unperturbed the receptor kinase activity. At concentration ranging from 30 nM to 5 microM, it activates apoptosis. FR18 seems therefore to have possible therapeutic applications in colon cancer.

Apoptosis↗
PubMed2006

Histone proteins determined in a human colon cancer by high-performance liquid chromatography and mass spectrometry.

The application of reversed-phase high-pressure liquid chromatography under gradient conditions and electrospray ion trap mass spectrometry (LC-ESI-MS) to the analysis of global modification levels of core histones is described. The optimised LC-ESI-MS method was applied for the first time to the characterisation of histones extracted from HT29, a human colon cancer cell line. Eight histones (H1-1, H1-2, H2A-1, H2A-2, H2B, H3-1, H3-2, H4) were separated on a C4 stationary phase with complete resolution, never reached in previous HPLC-MS methods, by using a gradient elution with the combined presence of heptafluorobutyric acid and formic acid as acidic modifiers in the mobile phase. Heptafluorobutyric acid was found to improve selectivity, whereas the presence of formic acid decreased ion suppression. Histones eluted from the column were detected with an ion trap mass spectrometer with an electrospray source. The peak averaged mass spectra were reconstructed by Mag Tran 1.0 software and the mass of the various isoforms of histones were derived. Method validation was conducted by performing the same sample analysis by coupling LC-ESI to a quadrupole-time-of-flight mass spectrometer (Q-TOF). The number of histone forms and their mass were found to differ not significantly from those obtained by ion trap mass spectrometer. Also the relative modifications abundance within the same histone type was found following the same trend as the two mass analysers. This method was then applied to the characterisation of changes in histone modification in HT29, never analysed by LC-MS before, treated with histone deacetylase inhibitors such as valproate and sodium butyrate, also used in preclinical trials as anticancer drugs. In particular, both the inhibitors produced a significant increase in H4 histone acetylated forms: 89% increase of the diacetyl dimethyl H4 form was observed with 1mM valproate supplementation, whereas 5 mM butyrate led to a 68% increase of the same form. Triacetyl monomethyl H4 (11,377 Da) and triacetyl dimethyl H4 (11,390 Da) were found only in cells treated with butyrate. Selective changes of H3 histone were detected with butyrate, in agreement with recently reported western blotting studies. Modifications in the H2A histone degree of acetylation were revealed by treatment of the cells with butyrate (H2A-1, H2A-2) and valproate (H2A-2). The results of the proposed methodology confirmed that inhibition of histone deacetylases caused histone hyperacetylation, responsible for decondensation and reorganization of interphase dynamic chromatin. This method resulted in selective and sensitive method to monitor variations in the acetylation and methylation state of histones after treatment of HT29 with inhibitors, and is therefore suitable for further application in new drug discovery for tumour therapy.

Acetylation↗
PubMed2005

Prognostic role of C-reactive protein in very old patients with acute ischaemic stroke.

BACKGROUND AND SCOPE: Recent literature has demonstrated that inflammation contributes to all phases of atherosclerosis and brain damage caused by stroke. In acute phase of cerebrovascular diseases biochemical markers of inflammation, such as C-reactive protein (CRP), could represent an indicator of severity of stroke, but few studies have verified this hypothesis, especially in very old patients. The aim of this study was to evaluate the role of CRP on short- and long-term prognosis in 75-year old and over elderly patients with acute ischaemic stroke. MATERIALS AND METHODS: We retrospectively evaluated CRP values (nephelometric method), performed within 12 h from hospital admission, in 196 elderly patients (124 females and 72 males with mean age+/-SD 83.32+/-10.46 years), discharged with diagnosis of acute ischaemic stroke, 68 of them with atherothrombotic large vessel stroke, 38 with lacunar stroke and 90 with cardioembolic stroke. We studied the relationship between CRP values and short-term prognosis [30-day mortality, length of hospitalization (LOS) and physical disability measured by modified Rankin scale and long-term prognosis (12-month mortality and re-hospitalization)]. RESULTS: Mean values of CRP were significantly higher in patients with cardioembolic stroke compared with atherothrombotic large vessel and lacunar stroke, in patients who died in the first 30 days from the acute event compared with survivors. LOS and physical disability score rose with increasing values of CRP for all subtypes of stroke. Higher CRP values were associated with the 12-month re-hospitalization for cerebrovascular events, whereas it did not influence the 12-month cumulative re-hospitalization and 12-month mortality. CONCLUSIONS: Elevation of CRP values at hospital admission could represent a negative prognostic index in elderly patients with ischaemic stroke, in particular, for short-term prognosis.

Aged↗
PubMed2004

9-Hydroxystearic acid upregulates p21(WAF1) in HT29 cancer cells.

Growing evidence supports the critical role of lipid peroxidation products in the control of cell proliferation. In previous studies we demonstrated the efficient restriction of the proliferation rate in several cell lines resulting from the in vitro treatment with endogenous lipid polar components of cell membranes. Among these, 9-hydroxystearic acid (9-HSA), a primary intermediate of lipid peroxidation, induced a significant arrest in G0/G1 in HT29 colon cancer cells. In response to 9-HSA treatment of HT29 we observed cell growth arrest and increase in p21(WAF1) expression both at the transcriptional and the translational levels. Growth of p21(WAF1)-deleted HCT116 human colon carcinoma cells was not inhibited by 9-HSA. We present evidence that p21(WAF1) is required for 9-HSA mediated growth arrest in human colon carcinoma cells.

Antineoplastic Agents↗
PubMed2002

Cytotoxic and cytostatic effects induced by 4-hydroxynonenal in human osteosarcoma cells.

Several studies point to the existence of an inverse correlation between cellular lipid peroxidation and both cell proliferation and neoplastic transformation. Furthermore, numerous results demonstrate that lipid peroxidation products affect central biochemical pathways and intracellular signalling at physiological concentrations. 4-Hydroxynonenal (HNE) is one of the most active products of lipid peroxidation. This work has focused on the evaluation of HNE nuclear content, so far never directly measured, by electrospray-ionization-mass-spectrometry (ESI/MS) and on the correlation between its concentration and the induced effects after exogenous administration. In a human osteosarcoma cell line (SaOS2), HNE exhibited an early cytotoxic effect characterized by apoptosis, cytostatic and differentiating effects characterized by slow growth, increase in alkaline phosphatase (ALP), and alpha5 integrin subunit content with decrease in tumorigenicity.

Aldehydes↗
PubMed2002

Mitochondrial nitric oxide localization in H9c2 cells revealed by confocal microscopy.

This study shows the presence of all three nitric oxide synthases (NOSs) and NOS activity in H9c2 cells cultured under non-stimulated conditions. By using the 4,5 diaminofluoresceindiacetate (DAF-2DA) fluorimetric nitric oxide (NO(*)) detection system we observed NO(*) production in H9c2 cells. As revealed by confocal microscopy, NO(*) fluorescence colocalizes in mitochondria labeled with Mito-Tracker Red CM-H(2)Xros. Upon stimulation with acetylcholine (Ach), which increased NOS activity by 75%, the colocalization coefficient C(green) value, calculated as Pearson's correlation, increased from 0.07 to 0.10, demonstrating an augmented presence of NO(*) in mitochondria. Conversely, the presence of NO(*) in mitochondria decreased following cells pretreatment with l-MonoMethylArginine (L-NMMA), a competitive inhibitor of NOS activity, as indicated by the reduction of the C(green) value to 0.02. This work confirms that the presence of NO(*) in mitochondria can be modulated in response to different fluxes of NO(*).

Acetylcholine↗
PubMed2002

Gas chromatography/mass spectrometric assay of endogenous cellular lipid peroxidation products: quantitative analysis of 9- and 10-hydroxystearic acids.

A sensitive, specific, accurate and reproducible gas chromatography/mass spectrometry method was developed for the assay of 9- and 10-hydroxystearic acids in samples obtained as cell extracts. The preparation of the samples required specific procedures to allow the analysis of both the free and the conjugated hydroxy acids as the corresponding methyl esters. The quantification used propyl-paraben as the internal standard and monitoring of a specific fragment of each isomeric hydroxy acid methyl ester, and allowed quantification of the conjugate and the free fractions of both 9- and 10-hydroxystearic acids. This method is suitable for identification and quantification (LOQ 1.8 and 4.4 ng, respectively) of these important metabolites of lipid peroxidation. In particular the development of an assay for the free 9-hydroxystearic acid methyl ester makes the method a reliable analytical tool for investigations of the role of this metabolite in the mechanisms of tumour cell proliferation.

Calibration↗
PubMed2001

Structural role of the proline residues of the beta-hinge region of p13suc1 as revealed by site-directed mutagenesis and fluorescence studies.

Site-directed mutagenesis, gel filtration, and fluorescence spectroscopy approaches were used to study the molecular hinge mechanism involved in the beta-strand-exchanged dimer formation of the cyclin-dependent protein kinase regulatory subunit p13(suc1) from Schizosaccharomyces pombe. Single and double mutants of residues Pro-90 and Pro-92 (P90V, P92V, and P90V/P92V) were prepared and assayed. Substitution of Pro-90 prevented dimer formation by arm exchange. However, single point mutations did not affect the two-state unfolding transition of wild-type p13(suc1) at equilibrium (i.e., wild type, DeltaG degrees (0,un) = 7.38 +/- 0.35 kcal mol(-1), vs P90V, DeltaG degrees (0,un) = 6.71 +/- 0.18 kcal mol(-1)). On the contrary, the double mutant unfolded with a complex transition, and the reaction was best described by a three-state model (N <==> I <==> U). Resolution of the state-dependent (native vs denatured) intrinsic fluorescence decay amplitudes of p13(suc1) showed that with P90V/P92V these parameters were affected at [GuHCl] significantly less than with wild-type and single mutant proteins. Moreover, with the latter products, fluorescence quenching measurements at 1 M GuHCl revealed linear Stern-Volmer plots with quenching constants typical of tryptophan residues located in a native environment (1.6 M(-1) < K(SV) < 2.3 M(-1)). Dissimilarly, with P90V/P92V a significant deviation from linearity of the Stern-Volmer plot was obtained. Nonlinear least-squares analysis of these data resolved the significant contribution of highly solvent-accessible emitting species (K(SV) = 26 M(-1)) consistent with large exposure of the tryptophan residues. These results are compatible with the existence of an intermediate unfolding state of the double mutation product. Thus, while single residue substitution studies give support to the primary role of Pro-90 in the p13(suc1) dimer formation by domain swapping, double residue substitution studies indicate the important role of the conserved repeat, Pro-x-Pro, for the proper beta-strand spatial organization and stability.

Cell Cycle Proteins↗
PubMed2001

The late effects of proton irradiation on cell growth, cell cycle arrest and apoptosis in a human melanoma cell line.

The aim of this work is the in vitro study of the late effects of single proton irradiation on HTB63 human melanoma cell growth, cell cycle and cell death. The experimental conditions were focused on analyzing the effects of irradiation on the periphery of tumour that can be, in clinical practice, close to critical organs. Confluent cell monolayers were irradiated with single doses ranging from 1 - 20 Gy, using proton beams having an energy of 22.6 MeV at the target. Antiproliferative effect of protons, cell cycle analysis and initiation of cell death, were followed 48 hours after irradiation. The inhibition of melanoma cell growth was observed, especially after single application of 12 and 16 Gy. Cell cycle analysis and cell viability have shown the G2/M and G1/G0 arrest of irradiated cells correlating with the increase of the applied dose. The flow cytometric analysis has shown presence of apoptotic nuclei. These data demonstrate that irradiation with protons, under the chosen experimental conditions, have significant effects on melanoma cell growth inhibition being dose dependent, G2/M cell cycle arrest and appearance of apoptotic nuclei, even 48 hours after irradiation. The results obtained may help the understanding of the relationship between cell proliferation, death and cell cycle regulation of melanomas after proton irradiation.

Apoptosis↗
PubMed2000

Length of hospitalization in elderly patients with community-acquired pneumonia.

Community-acquired pneumonia (CAP) is a serious social and medical problem in the elderly. Mortality, hospitalization and length of stay increase with age. The aim of this study was to determine the risk factors associated with prolonged hospital stay in elderly patients with CAP. Clinical and laboratory data were collected for 115 community-living patients, 65 years old and over, admitted to the geriatric ward of a University Hospital from 1995 to 1998 because of symptoms and signs of pneumonia confirmed by a pulmonary infiltrate on chest x-ray. We divided the patients into two groups, with length of stay more than 13 days (70 patients, cases), and length of stay less than 13 days (45 patients, controls) according to Diagnosis Related Groups criteria for complicated and uncomplicated pneumonia, respectively. A prolonged hospital stay was associated with a higher fever peak and a higher number of days with fever (p<0.005), greater comorbidity (p<0.001), urinary catheterization and secondary urinary infections (p<0.001), higher erythrocyte sedimentation rate (p<0.001), dehydration (p<0.005), and caloric-proteic malnutrition (p=0.01). In conclusion, knowledge of the risk factors for prolonged hospital stay in elderly patients with CAP may be used to identify high-risk patients, prevent the risks with prophylactic measures, and contain the costs of hospitalization.

Aged↗
PubMed2000

Chromosome aberrations, micronuclei, and activity of superoxide dismutases in human lymphocytes after irradiation in vitro.

The goal of this study was to provide data on the dose-dependent production of dicentrics and micronuclei in human lymphocytes irradiated with 22.6 MeV protons and to estimate the possible contribution of intracellular superoxide dismutases (SOD) to the relative biological effectiveness (RBE) of protons. For the dose-response study, heparinized whole blood of a healthy volunteer was irradiated with protons and X-rays employing radiation doses of 0.5-4 Gy. Three biological endpoints were analyzed: chromosomal aberrations, micronuclei, and specific activity of cytosolic (CuZnSOD) and mitochondrial (MnSOD) superoxide dismutases in harvested human blood cells. Dicentric dose-response curves fit a linear-quadratic form (alpha = 0.094 +/- 0.006, beta = 0.032 +/- 0.001) induced with X-rays and (alpha = 0.119 +/- 0.057, beta = 0.029 +/- 0.014) for 22.6 MeV protons. Protons were more effective than X-rays in producing exchanges, particularly at 0.5 and 1 Gy. In contrast to X-ray irradiated samples where a significant increase in the specific activity of MnSOD was recorded (up to a radiation dose of 1 Gy), irradiation with protons markedly reduced its activity. As a consequence of the reduced activity of MnSOD, the chromosomal dose-response curve became quadratic. The RBE for dicentrics varies with dose (from 2.2 to 1.01) and reduced activity of MnSOD is an important contributor to the RBE of protons. SODs, particularly MnSOD, play an important role in defending DNA from reactive oxygen species. A reduced activity of SOD, particularly MnSOD, is an important contributor to the RBE of protons.

Cell Division↗
PubMed2000

A real-time two-dimensional pulsed-wave Doppler system.

An experimental system was developed to acquire and visualise in real-time two-dimensional (2-D) velocity maps. Data acquisition is performed by using a modified commercial echograph based on a 5-MHz, 128-element linear-array transducer with electronic focussing and beam steering. Additional electronics were integrated into the echograph to implement a 2-D Doppler system capable of measuring the velocity component on the scanning plane. Suitable axial and lateral scanning methods were studied to obtain Doppler measurements over a scanning area. A colour image of the estimated velocity field is presented in real time on a personal computer using different visualisation techniques. The system performance was tested experimentally both in vitro and in vivo on a human carotid artery.

Blood Flow Velocity↗
PubMed2000

Arterial blood gas analysis and alveolar-arterial oxygen gradient in diagnosis and prognosis of elderly patients with suspected pulmonary embolism.

BACKGROUND: Arterial blood gas analysis (BGA) remains a first-step diagnostic approach in patients with suspected pulmonary embolism (PE). The aim of this study was to evaluate BGA parameters in elderly patients with suspected pulmonary embolism for diagnosis and 14-day prognosis. METHODS: We performed a retrospective cohort observational study of 6 years (1994-1999) in a 60-bed acute geriatric ward of University Hospital in Siena, Italy. Room air arterial oxygen partial pressure (pO2), arterial carbon dioxide partial pressure (pCO2), pH, arterial oxyhemoglobin saturation (SO2), and alveolar-arterial oxygen gradient [D(A-a)O2] were performed on hospital admission of 75 patients with confirmed PE (CPE) and were compared with data from 43 patients with unconfirmed PE (UCPE). The same parameters of 54 CPE surviving patients were compared with 21 CPE nonsurviving patients. RESULTS: Significantly lower PO2 and SO2, and higher DA-aO2 were found in CPE patients. Respiratory alkalosis was found in one third of the patients in both groups (no significant difference). In the CPE group, there was a significantly lower SO2 in nonsurviving patients, without significant differences for the other parameters. Metabolic acidosis was significantly more frequent in nonsurviving patients. CONCLUSION: More severe hypoxemia, oxyhemoglobin hyposaturation, and higher D(A-a)O2 are associated with the diagnosis of PE in elderly patients. Respiratory alkalosis is less frequent than in younger patients, and metabolic disorders are negative prognostic indicators.

Aged↗