Search PubMed⌕ Search

Biomedical subjects

C Lamberti

Publications and source records attributed to C Lamberti.

At least 19 recordsLinked to original sources
PubMed2006

Direct IR observation of vibrational properties of carbonyl species formed on Pd nano-particles supported on amorphous carbon: comparison with Pd/SiO2-Al2O3.

By diluting optically opaque carbon-supported Pd particles in silica Aerosil we succeeded in observing the IR bands of adsorbed carbonyls and extracting information on the particle dispersion. Comparison with literature single crystal data and with silica-alumina supported Pd allowed us to make an assignment in terms of linear and 2-fold bridged carbonyls formed on Pd(111) and Pd(100) faces. Two Pd/C samples have been investigated. The relative intensities of the two carbonyl families observed on the two samples are consistent with the Pd dispersion independently measured with CO chemisorption, TEM and EXAFS analysis.

Aldehydes↗
PubMed2006

Microsatellite instability did not predict individual survival of unselected patients with colorectal cancer.

INTRODUCTION: High microsatellite instability (MSI-H) occurs in about 15% of colorectal cancers (CRC) and clinical as well as pathological features differ from tumours exhibiting low microsatellite instability (MSI-L) or microsatellite stability (MSS). Conflicting data exists about the relevance of MSI in predicting the prognosis and benefit of 5-fluorouracil (5-FU) based chemotherapy in patients with CRC. We investigated the usefulness of MSI as a predictor of distinct clinical attributes influencing recurrence rate and disease-free survival (DFS) subject to the use of adjuvant or palliative chemotherapy with 5-FU in stage II- stage IV CRC. METHODS: We collected data and tumours of 416 consecutive stage I to IV CRC patients from 2000 to 2002, and followed them for a median time of 33 months. Microsatellite loci recommended by the National Cancer Institute were analysed. Cox proportional hazard modelling was used to compare clinical data and survival as well as associations for MSI and 5-FU treatment status of patients with MSI-H, MSI-L or MSS CRC. RESULTS: We identified 52 MSI-H (13%), 21 MSI-L (5%) and 343 MSS (82%) tumours. CRC with MSI-H tended to have a decreased likelihood of metastasising to regional lymph nodes (p=0.055), whilst age of diagnosis and tumour location did not differ. In an analysis that did not take into account the use of chemotherapy, univariate and multivariate analyses failed to show a difference between MSI-H and MSS groups with respect to disease-free and overall survival. Furthermore, survival under application of 5-FU did not correlate with MSI status. CONCLUSION: No clear influence of MSI status on overall survival and response to 5-FU chemotherapy was found.

Aged↗
PubMed2006

On the fraction of CrII sites involved in the C2H4 polymerization on the Cr/SiO2 Phillips catalyst: a quantification by FTIR spectroscopy.

An estimation of the fraction of Cr(II) sites involved in the C(2)H(4) polymerization on a Cr(II)/SiO(2) Phillips catalyst has been obtained by means of in situ alternated CO adsorption and C(2)H(4) polymerization FTIR experiments: about 28% of the total surface sites react fast with C(2)H(4), while a lower fraction, which depends upon the temperature reaction conditions, is more slowly involved, in agreement with XANES results.

Journal Article↗
PubMed2006

[Adjuvant and palliative chemotherapy of colorectal cancer in Germany outside controlled trials].

BACKGROUND AND OBJECTIVE: Colorectal cancer is the second most common malignant tumour in Germany with an unfavorable prognosis especially in a locally advanced or metastasizing stage. Although adjuvant and palliative chemotherapy significantly improve 5-year survival, consensus recommendations have in the past been inadequately transformed into clinical practice. It was the aim of this study to analyse the implementation of existing guidelines in a cohort from a defined area of Germany. PATIENTS AND METHODS: In a multicentre study done between January 2000 and January 2002, tumour stage, primary care, adjuvant or palliative chemotherapy and follow-up of 444 patients (216 males, 228 females) with newly diagnosed colorectal cancer were recorded. RESULTS: 301 patients had colonic and 143 patients rectal cancer. The median age at diagnosis was 65 11.3 years. 36 of 96 (38%) patients with stage II colon cancer and 66 of 87 (76%) with stage III disease received adjuvant chemotherapy. 8 of 51 (16%) patients with rectal cancer stage II and 22 of 38 (58%) patients with stage III underwent adjuvant radio- and chemotherapy. The 68 of 84 (81%) patients with stage IV CRC who received palliative chemotherapy were given almost exclusively 5-FU monotherapy. Initial or sequential combination chemotherapy with oxaliplatin or irinotecan were performed in only 24 of 84 (29%) patients. CONCLUSIONS: Stage III colon cancer was predominantly treated according to the existing standard guidelines. In contrast combined radio- and chemotherapy for rectal cancer stage II and III was only performed in one third of the patients, another third receiving neither adjuvant radiation nor chemotherapy. Initial combined or sequential combined chemotherapy for metastasizing colorectal cancer was rarely performed.

Adult↗
PubMed2006

Frequency of hereditary non-polyposis colorectal cancer among unselected patients with colorectal cancer in Germany.

INTRODUCTION: Hereditary non-polyposis colorectal cancer (HNPCC) is a major form of familial colorectal cancer (CRC). It is diagnosed when either the Amsterdam criteria (AC) are fulfilled or mutations in one of the mismatch repair (MMR) genes have been identified. This project aims at estimating the proportion of HNPCC among unselected patients with CRC. PATIENTS AND METHODS: During a period of 2 years, a total of 351 non-selected patients with CRC were registered prospectively. 92 patients met the Bethesda criteria (9 of them fulfilled the AC) and 259 did not. 348 tumours were examined for microsatellite instability (MSI) and expression of MMR proteins. RESULTS: MSI-H and MSI-L were identified in 17 and 6%, respectively. Loss of MSH2 or MLH1 was found in 1.5 and 8.8%, respectively. Based on the results of tumour tissue analyses, 80 patients with MSI and/or loss of MSH2 or MLH1 expression were identified as candidates for germline mutation screening. DNA of 40/80 patients was available. These patients were screened for MSH2 and MLH1 mutations; 19/40 patients with MSI and normal MSH2 or MLH1 expression were screened for mutations in MSH6. Three patients had relevant MMR gene mutations and six variants of unknown functional relevance were detected. CONCLUSIONS: After adjusting for the cases not evaluable for germline mutations, 1.7% of the CRC patients had HNPCC proven by molecular genetics.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Tracking of left ventricular long axis from real-time three-dimensional echocardiography using optical flow techniques.

Two-dimensional echocardiography (2DE) is routinely used in clinical practice to measure left ventricular (LV) mass, dimensions, and function. The reliability of these measurements is highly dependent on the ability to obtain nonforeshortened long axis (LA) images of the left ventricle from transthoracic apical acoustic windows. Real time three-dimensional echocardiography (RT3DE) is a novel imaging technique that allows the acquisition of dynamic pyramidal data structures encompassing the entire ventricle and could potentially overcome the effects of LA foreshortening. Accordingly, the aim of this paper was to develop a nearly automated method based on optical flow techniques for the measurement of the left ventricular (LV) LA throughout the cardiac cycle from RT3DE data. The LV LA measurements obtained with the automated technique has been compared with LA measurements derived from manual selection of the LA from a volumetric display of RT3DE data. High correlation (r = .99, SEE = 1.8%, y = .94x + 5.3), no significant bias (-0.18 mm), and narrow limits of agreement (SD: 1.91 mm) were found. The comparison between the LA length derived from 2DE and RT3DE data showed significant underestimation of the 2DE based measurements. In conclusion, this study proves that RT3DE data overcome the effects of foreshortening and indicates that the method we propose allows fast and accurate quantification of LA length throughout the cardiac cycle.

Algorithms↗
PubMed2005

FTIR investigation of the H2, N2, and C2H4 molecular complexes formed on the Cr(II) sites in the Phillips catalyst: a preliminary step in the understanding of a complex system.

This work reports the first complete FTIR characterization of H2, N2 and C2H4 molecular complexes formed on the Cr(II) sites in the Phillips catalyst. The use of a silica aerogel as support for Cr(II) sites, substituting the conventional aerosil material, allowed us to obtain a remarkable increase in the signal-to-noise ratio of the IR spectra of adsorbed species. The improvement is directly related to an increase of the surface area of the support (approximately 700 m2 g(-1)) and to an almost complete absence of scattering [Groppo et al., Chem. Mater. 2005, 17, 2019-2027]. The use of this support and the adoption of suitable experimental conditions results, for the first time, in the clear observation of H2 and N2 adducts formed on two different types of Cr(II) sites, thus yielding important information on the coordinative state of the Cr(II) ions, which well agrees with the evidences provided in the past by other probe molecules. Furthermore, we report the first complete characterization of the C2H4 pi-complexes formed on Cr(II) sites. These results are particularly important in the view of the understanding of the polymerization mechanism, since the C2H4 coordination and the formation of pi-bonded complexes are the first steps of the reaction.

Journal Article↗
PubMed2005

EXAFS and XANES investigation of the ETS-10 microporous titanosilicate.

In this work, we report state-of-the-art analysis of both Ti K-edge high-resolution XANES and EXAFS data collected on the ETS-10 molecular sieve at the GILDA BM8 beamline of the ESRF facility. The interatomic distances and the angles obtained in our EXAFS study are in fair agreement with the single-crystal XRD data of Wang and Jacobson (Chem. Commun. 1999, 973) and with the recent ab initio periodic study of Damin et al. (J. Phys. Chem. B 2004, 108, 1328) Differently from previous EXAFS work (J. Phys. Chem. 1996, 100, 449), our study supports a model of ETS-10 where the Ti atoms are bonded with two equivalent axial oxygen atoms. This model is also able to reproduce the edge and the post-edge region of the XANES spectrum. Conversely, the weak but well-defined pre-edge peak at 4971.3 eV can be explained only by assuming that a fraction of Ti atoms are in a local geometry similar to that of the pentacoordinated Ti sites in the ETS-4 structure. These Ti atoms in ETS-10 should be the terminal of the -Ti-O-Ti-O-Ti- chains, of which the actual number is strongly increased by the high crystal defectivity (Ti vacancies).

Journal Article↗
PubMed2005

[Early diagnosis of colorectal tumors].

Colorectal cancer (CRC) is one of the most common causes of cancer mortality in Western countries. Approximately six percent of the population will develop colorectal cancer during life. Individuals older than 50 years or with a family history for colorectal tumors as well as patients with an inflammatory bowel disease have an increased risk for CRC. A significant reduction of colorectal cancer mortality can be achieved by screening of asymptomatic patients and removal of premalignant adenomatous polyp precursors. Colonoscopy is recognized as the gold standard, but in future virtual colonoscopy might be a reasonable addition. Asymptomatic individuals with an average risk for CRC should be screened from the age of 50 and then every 10 years if the examination showed no pathological findings. When the individual or family history indicate a higher risk for a colorectal neoplasia, screening should begin at the age of 40 or 10 years before the earliest tumor occurrence in the family. Families with hereditary CRC require a special surveillance.

Chronic Disease↗
PubMed2005

Population-based registration of unselected colorectal cancer patients: five-year survival in the region of Bonn/Rhine-Sieg, Germany.

INTRODUCTION: Epidemiological data of colorectal cancer are sparse and often incomplete. Therefore, we initiated a population-based examination of five-year survival of colorectal cancer patients. METHODS: For complete registration, diagnosis and tumour stage of all patients in the region of Bonn/Rhine-Sieg were assessed independently according to reports of medical practitioners and pathologists. Each patient was followed by a standardised questionnaire during a period of five years. RESULTS: Between June and November, 1994 348 patients were registered. Median age at diagnosis was 69 years for males (n = 160) and 72 years for females (n = 188). According to the UICC classification 18, 26, 23 and 26 % had stage I-IV tumours, respectively; the tumour stage remained unclear in 7 %. Adjuvant (radio)-chemotherapy was indicated in 89 patients, but only 49 % of these were treated. Five-year overall survival (OS) and relative overall survival were 41 and 54 %, respectively. Although disease-free survival (DFS) was significantly better for early stage colorectal cancer, OS did not differ significantly between stage I and stage III tumours. Young patients diagnosed before the age of 50 had a significantly lower DFS. These data were comparable with other European countries but were lower than data reported in the USA. DISCUSSION: The high rate of patients with stage IV colorectal cancer and the low proportion of patients receiving adjuvant (radio)-chemotherapy according to international or national consensus recommendations were disappointing. Although data were comparable with other European countries more efforts are necessary to establish effective screening programs for asymptomatic patients and to increase the willingness for standardised adjuvant treatment.

Adult↗
PubMed2004

Electronic and vibrational properties of a MOF-5 metal-organic framework: ZnO quantum dot behaviour.

UV-Vis DRS and photoluminescence (PL) spectroscopy, combined with excitation selective Raman spectroscopy, allow us to understand the main optical and vibrational properties of a metal-organic MOF-5 framework. A O(2-)Zn(2+)[rightward arrow] O(-)Zn(+) ligand to metal charge transfer transition (LMCT) at 350 nm, testifies that the Zn(4)O(13) cluster behaves as a ZnO quantum dot (QD). The organic part acts as a photon antenna able to efficiently transfer the energy to the inorganic ZnO-like QD part, where an intense emission at 525 nm occurs.

Journal Article↗
PubMed2004

Quantification of left ventricular modification in weightlessness conditions from the spatio-temporal analysis of 2D echocardiographic images.

Two-dimensional echocardiography (2DE) performed during flights with a parabolic trajectory to simulate weightlessness provides a unique means to study left ventricular (LV) modifications to prevent post-flight orthostatic intolerance in astronauts. However, conventional analysis of 2DE is based on manual tracings and depends on experience. Accordingly, the aim was objectively to quantify, from 2DE images, the LV modifications related to different gravity levels, by applying a semi-automated level-set border detection technique. The algorithm validation was performed by the comparison of manual tracing results, obtained by two independent observers with 20 images, with the semi-automated measurements. To quantify LV modifications, three consecutive cardiac cycles were analysed for each gravity phase (1 Gz, 1.8 Gz, 0 Gz). The level-set procedure was applied frame-by-frame to detect the LV endocardial contours and obtain LV area against time curves, from which end-diastolic (EDA) and end-systolic (ESA) areas were computed and averaged to compensate for respiratory variations. Linear regression (y = 0.91x + 1.47, r = 0.99, SEE:0.80cm2) and Bland-Altman analysis (bias = -0.58 cm2, 95% limits of agreement= +/- 2.14cm2) showed excellent correlation between the semi-automatic and manually traced values. Inter-observer variability was 5.4%, and the inter-technique variability was 4.1%. Modifications in LV dimensions during the parabola were found: compared with 1 Gz values, EDA and ESA were significantly reduced at 1.8 Gz by 8.8 +/- 5.5% and 12.1 +/- 10.1%, respectively, whereas, during 0 Gz, EDA and ESA increased by 13.3 +/- 7.3% and 11.6 +/- 5.1%, respectively, owing to abrupt changes in venous return. The proposed method resulted in fast and reliable estimations of LV dimensions, whose changes caused by different gravity conditions were objectively quantified.

Adult↗
PubMed2002

Fast interactive real-time volume rendering of real-time three-dimensional echocardiography: an implementation for low-end computers.

Real-time three-dimensional echocardiography (RT3DE) is an innovative cardiac imaging modality. However, partly due to lack of user-friendly software, RT3DE has not been widely accepted as a clinical tool. The object of this study was to develop and implement a fast and interactive volume renderer of RT3DE datasets designed for a clinical environment where speed and simplicity are not secondary to accuracy. Thirty-six patients (20 regurgitation, 8 normal, 8 cardiomyopathy) were imaged using RT3DE. Using our newly developed software, all 3D data sets were rendered in real-time throughout the cardiac cycle and assessment of cardiac function and pathology was performed for each case. The real-time interactive volume visualization system is user friendly and instantly provides consistent and reliable 3D images without expensive workstations or dedicated hardware. We believe that this novel tool can be used clinically for dynamic visualization of cardiac anatomy.

Artifacts↗
PubMed2002

Changes in left ventricular size during parabolic flights by two-dimensional echocardiography and level set method.

This study aims to evaluate changes on cardiac chambers size, induced by gravitational stresses. During parabolic flight, seven subjects underwent 2-D transthoracic echocardiography at three different gravity phases (1 Gz, 1.8 Gz, and 0 Gz). LV endocardial borders were detected applying a semi-automatic segmentation procedure based on level set methods. LV cavity area was computed frame-by-frame for a whole cardiac cycle during each gravity phase. Expected modifications in LV area with different gravity were found: at 1.8 Gz, end-diastolic (ED) and end-systolic (ES) areas were significantly (p<0.05) reduced of 10.7 +/- 5.4% and 21.6 +/- 11.1% respectively, compared to 1 Gz values, while they were increased of 11.2 +/- 5.4% and 11.1 +/- 6% during 0 Gz. Fractional area change was augmented of 20.9 +/- 29.1% at 1.8 Gz, while it remained unchanged at 0 Gz, compared with 1 Gz values. Furthermore, LV filling due to atrial contraction was increased at 0 Gz of 39 +/- 35.6%.

Adult↗
PubMed2001

Vibrational structure of titanium silicate catalysts. A spectroscopic and theoretical study.

A thorough analysis of the vibrational features of the titanium silicalite-1 (TS-1) catalyst is presented, based on quantitative IR measurements, Raman and resonant Raman experiments, quantitative XANES, and quantum chemical calculations on cluster and periodic models. The linear correlation of the intensity of the IR and Raman bands located at 960 and 1125 cm(-1) and the XANES peak at 4967 eV with the amount of tetrahedral Ti are quantitatively demonstrated. Raman and resonant Raman spectra of silicalite and TS-1 with variable Ti content are presented, showing main features at 960 and 1125 cm(-1) associated with titanium insertion into the zeolite framework. The enhancement of the intensity of the 1125 cm(-1) feature and the invariance of the 960 cm(-1) feature in UV-Raman experiments, are discussed in terms of resonant Raman selection rules. Quantum chemical calculations on cluster models Si[OSi(OH)(3)](4) and Ti[OSi(OH)(3)](4) at the B3LYP/6-31G(d) level of theory provide the basis for the assignment of the main vibrational contributions and for the understanding of Raman enhancement. The resonance-enhanced 1125 cm(-1) mode is unambiguously associated with a totally symmetric vibration of the TiO(4) tetrahedron, achieved through in-phase antisymmetric stretching of the four connected Ti-O-Si bridges. This vibration can also be described as a totally symmetric stretching of the four Si-O bonds pointing toward Ti. The resonance enhancement of this feature is explained in terms of the electronic structure of the Ti-containing moiety. Asymmetric stretching modes of TO(4) units show distinct behavior when (i) T is occupied by Si as in perfect silicalite, (ii) T is occupied by Ti as in TS-1, or (iii) the oxygen atom belongs to an OH group, such as in terminal tetrahedra of cluster models and in real defective zeolites. Asymmetric SiO(4) and TiO(4) stretching modes appear above and below 1000 cm(-1), respectively, when they are achieved through antisymmetric stretching of the T-O-Si bridges, and around 800 cm(-1) (in both SiO(4) and TiO(4)) when they involve symmetric stretching of the T-O-Si units. In purely siliceous models, the transparency gap between the main peaks at 800 and 1100 cm(-1) contains only vibrational features associated with terminal Si-OH groups, while in Ti-containing models it contains also the above-mentioned asymmetric TiO(4) modes, which in turn are strongly coupled with Si-OH stretching modes. Calculations on periodic models of silicalite and TS-1 free of OH groups using the QMPOT embedding method correctly reproduce the transparency gap of silicalite and the appearance of asymmetric TiO(4) vibrations at 960 cm(-1) in TS-1. Finally, we demonstrate, for the first time, that the distortion of the tetrahedral symmetry around Ti caused by water adsorption quenches the UV-Raman enhancement of the 1125 cm(-1) band.

Journal Article↗
PubMed2001

Expression and DNA binding activity of the Ku heterodimer in bladder carcinoma.

BACKGROUND: The Ku protein is a tightly associated heterodimer, comprised of 70-kilodalton (kD) and 86-kD subunits, that forms the DNA-dependent protein kinase (DNA-PK) complex together with the 470-kD DNA-PKcs catalytic subunit, and is involved mainly in DNA double-strand breaks (DSBs) repair. The objective of the current study was to investigate the expression and DNA-binding activity of the Ku protein in fresh tissues from patients with bladder carcinoma and to compare it with that in nontumor tissues obtained from the same organ. Moreover, the DNA-binding activity of Ku was assessed after exposure of the tumor cells to 1 or 2 grays (Gy) of X-rays. Furthermore, the level of phosphorylated Ku was analyzed in both the nuclear and cytoplasmic compartment of normal tissue after exposure to 2 Gy of X-rays. METHODS: The expression and DNA-binding activity of Ku protein were assessed in tumor samples from patients who all were diagnosed with transitional cell carcinoma (TCC) of the bladder using Western blot analysis and the electrophoretic mobility shift assay, respectively. RESULTS: Enhanced Ku activity and expression were found in tumor tissue compared with normal tissue for each patient. Moreover, variations in Ku activity were found in a dose-dependent manner after the tumor cells were exposed to 1 or 2 Gy of X-rays. A decrease in phosphorylated Ku in the cytoplasm and a parallel increase in the nucleus of normal tissue cells were observed after exposure to X-rays. CONCLUSIONS: The results of the current study suggest a possible role of Ku in regulating the DNA-PK activity of DSBs repair in bladder tumors.

Aged↗