I. Ortalli

Publications (39)38.36 Total impact

• Article: Conformational changes in hemoglobin triggered by changing the iron charge

  S. Croci, K. Achterhold, I. Ortalli, F. G. Parak
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  ABSTRACT: In this work the hemoglobin conformational changes induced by changing the iron charge have been studied and compared with Myoglobin. Mössbauer spectroscopy was used to follow the change of the iron conformation. In order to compare the conformational relaxation of hemoglobin and myoglobin, and to study a possible influence of the quaternary structure, an intermediate metastable state of hemoglobin has been created by low temperature X-ray irradiation of methemoglobin. The irradiation reduces the Fe(III) of the heme groups to Fe(II) Low Spin, where the water is still bound on the sixth coordination. Heating cycles performed at temperatures from 140K to 200K allow the molecules to overcome an activation energy barrier and to relax into a stable conformation such as deoxy-hemoglobin or carboxy-hemoglobin, if CO is present. Slightly different structures (conformational substates) reveal themselves as a distribution of energy barriers (ΔG#). The distribution of the activation energy, for the decay of the Fe(II) Low Spin intermediate, has been fitted with a Gaussian. For comparison, published myoglobin data were re-analysed in the same way. The average energy value at characteristic temperature is very similar in case of myoglobin and hemoglobin. The larger Gaussian energy distribution for myoglobin with respect to hemoglobin shows that more conformational substates are available. This may be caused by a larger area exposed to water. In hemoglobin, part of the surface of the chains is not water accessible due to the quaternary structure.
  Hyperfine Interactions 04/2012; 185(1):103-110. · 0.21 Impact Factor
• Article: Hemoglobin oxidative stress

  S. Croci, I. Ortalli, G. Pedrazzi, G. Passeri, P. Piccolo
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  ABSTRACT: Venous blood obtained from healthy donors and from patients suffering from breast cancer have been treated with acetylphenylhydrazine (APH) for different time. Mössbauer spectra of the packed red cells have been recorded and compared. The largest difference occurs after 50 min of treatment with APH where the patient samples show a broad spectral pattern indicating an advanced hemoglobin oxidation. These results may have some relevance in early cancer diagnosis.
  Hyperfine Interactions 04/2012; 126(1):47-52. · 0.21 Impact Factor
• Article: Te125 Mössbauer studies of some binary magnetic Me2Te3 type semiconductors

  I. Ortalli, V. Fano, P. Gibart
  physica status solidi (a) 02/2006; 15(1):K45 - K49. · 1.21 Impact Factor
• Article: Acetylphenylhydrazine induced haemoglobin oxidation in erythrocytes studied by Mössbauer spectroscopy.

  S Croci, G Pedrazzi, G Passeri, P Piccolo, I Ortalli
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  ABSTRACT: The oxidative action of acetylphenylhydrazine (APH) on red blood cells obtained from healthy donors and from patients with breast cancer has been investigated by Mössbauer spectroscopy. Whole blood was incubated with APH for different time periods and the Mössbauer spectra of the packed red cells were recorded and compared. The evolution with time of the oxidation products has been followed. The largest difference in red cells analysis between healthy persons and patients was found after about 50 min of treatment where Mössbauer spectra of patient samples show a much broader spectral pattern due to an advanced haemoglobin oxidation.
  Biochimica et Biophysica Acta 12/2001; 1568(1):99-104. · 4.66 Impact Factor
• Article: Study of dental materials by laser beam scanning.

  V Fano, W Y Ma, I Ortalli, K Pozela
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  ABSTRACT: Several properties of dental materials are characterized by dimensional variation induced by different parameters. In this work a non-contact method used for measurement of linear dimensional variation is shown. The accuracy is +/- 1 micron for sample length ranging from 1 to 70 mm.
  Biomaterials 09/1998; 19(16):1541-5. · 7.40 Impact Factor
• Article: [The effects of hematin and Mössbauer gamma radiation in cellular inactivation].

  I Ortalli
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  ABSTRACT: In the present work we report the results of an investigation on cultures of bone marrow mononuclear cells collected from normal donors and patients with chronic myelogenous leukaemia and cultures of the human osteosarcoma cell line "MG-63" and the human osteoblastic cell line "HOBIT". We have examined the combined effects of hematin and 14.4 KeV gamma-radiation from a Mössbauer source. Growth stimulation has been observed when hematin is added to normal cultures, while growth inhibition is observed when hematin is added to tumor cultures. Different degrees of growth inhibition were observed in both cultures when hematin alone and hematin plus gamma-rays were administered to the cultures. No significant effect could be attributed to irradiation alone, while hematin plus irradiations show a large inhibition that expected for pure additive effects.
  Acta bio-medica: Atenei Parmensis 02/1998; 69(1-2):27-35.
• Article: Convection during the vertical Bridgman growth of Hg1−xCdxTe

  V. Fano, I. Ortalli, K. Pozela, G. Meletti
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  ABSTRACT: Two different structures, obtained with specific growth parameters, in Hg1–x Cd x Te single crystals synthesized by the vertical Bridgman technique, are shown. A structure (small vertical line-shaped defects) located in the central part of the charge along the growth axis can be ascribed to convection induced by melt–solid interface curvature. The other structure, obtained in the first-to-freeze region of the ingot, when the temperature of the cold zone of the furnace is constant and a few degrees lower than the solidification one, can be ascribed to the convection rolls frozen in the solid matrix.
  Journal of Materials Science 01/1998; 33(6):1627-1632. · 2.02 Impact Factor
• Article: Polymerization shrinkage of microfilled composites determined by laser beam scanning.

  V Fano, I Ortalli, S Pizzi, M Bonanini
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  ABSTRACT: An He-Ne scanning laser beam was used to measure for the first time the linear shrinkage of light-cured microfilled composites. A low-power beam, which has a wavelength (632.8 nm) different from the polymerization wavelength (approximately 450 nm), was used. In these conditions no shrinkage is induced by the laser light. This method of measurement makes it possible to analyse small samples with a very low error (1.1 microns). Five different materials were tested using 10-20 mg specimens, and the shrinkage process was examined in detail over 2 days. All these materials showed shrinkage of more than 50% of their original length after 1 min of irradiation and approximately 99% of the total shrinkage occurred 4 h after irradiation.
  Biomaterials 04/1997; 18(6):467-70. · 7.40 Impact Factor
• Article: Effects of hematin and Mössbauer gamma-radiation on human osteosarcoma cell lines

  I. Ortalli, G. Pedrazzi, V. Fano, W. Y. Ma, S. Z. Cai, N. Giuliani, M. Passeri
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  ABSTRACT: In the present work we report an investigation on cultures of the human osteosarcoma cell line «MG-63» and the human osteoblastic cell line «HOBIT». We have examined the combined effects of hematin and 14.4keV gamma-radiation from a Mössbauer source. Preliminary results seem to confirm the trend already observed for the bone marrow system. Different degrees of growth inhibition were observed when hematin alone and hematin plus gamma-rays were administered to the cultures. It was previously found that hematin has no toxic effects on normal cells up to a concentration of 10−4 M, but the same concentration produces various degrees of inhibition on cultures of tumor cells. While no significant effect could be attributed to irradiation alone, hematin plus irradiations show a larger inhibition than that expected for pure additive effects.
  Il Nuovo Cimento D 01/1996; 18(2):359-363.
• Article: Porosity in composite resins.

  V Fano, I Ortalli, K Pozela
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  ABSTRACT: Porosity in the pastes of composite resins before and after polymerization has been measured. The influence of the diameter of the extrusion orifices and the spatulation of the chemically-activated pastes has been evaluated. Considering that thin layers of these materials are transparent, the investigation has been carried out mainly by analysis of approximately 300 microns or lower thickness layers, that are still transparent under the microscope. Generally, there was a significant dependence of the porosity on the orifice diameter. However, this rule showed some exceptions. As far as the chemically-activated pastes were concerned, in all examined cases the number of small size (10-40 microns) porosities increased after spatulation.
  Biomaterials 12/1995; 16(17):1291-5. · 7.40 Impact Factor
• Article: Convection in the bridgman growth of narrow-gap semiconductors

  R. Breschi, V. Fano, I. Ortalli
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  ABSTRACT: The free convection in the melt during the crystal growth of small-gap semiconductors, and its influence on the electrical properties are discussed. Dimensionaless parameters of the fluid flow, electrical properties of PbTe, Pb1−x Sn x Te and Hg1−x Cd x Te single crystals, grown by vertical Bridgman technique at very low velocity, and some structures, found in these materials, support the presence of free convection.
  Il Nuovo Cimento D 08/1995; 17(9):1067-1075.
• Article: Distribution of components in single crystals grown from completely mixed melts of Hg1−xCdxTe and Pb1−xSnxTe systems

  V. Fano, W. Y. Ma, I. Ortalli, G. Meletti
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  ABSTRACT: A method is given to calculate the maximum compositional gradient in single crystals, grown by unidirectional solidification, of binary or pseudobinary materials. The calculation is based on the data obtained from the phase diagrams. Compositional gradients of HgTe-CdTe and PbTe-SnTe systems along the growth axis are shown.
  Il Nuovo Cimento D 01/1995; 17(2):205-208.
• Article: Iron-nickel superstructure in metal particles of Alfianello meteorite

  R. B. Scorzelli, I. Souza Azevedo, I. Ortalli, G. Pedrazzi, A. Bonazzi
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  ABSTRACT: We report on Mssbauer spectroscopy in metal particles of the Alfianello meteorite. The FeNi 50-50 ordered phase (tetrataenite) was detected in coexistence with a high proportion of the corresponding disordered phase. The order-disorder process is discussed in terms of shock events.
  Hyperfine Interactions 11/1994; 83(1):479-482. · 0.21 Impact Factor
• Article: Investigations on five iron meteorites

  A. Bonazzi, K. Jiang, I. Ortalli, G. Pedrazzi, X. Zhang
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  ABSTRACT: In the present paper, we report an analysis of five iron meteorites belonging to the private collection of the mineralogy museum of the University of Parma (Italy). The collection is made up of eighteen samples, collected over two centuries. Up to now, they have never been studied by spectroscopical techniques and their classification was estimated on the basis of morphological inspection. Electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), and Mssbauer spectroscopy (MS) have been used to analyse the samples.
  Hyperfine Interactions 11/1994; 91(1):541-545. · 0.21 Impact Factor
• Article: Some comments on the effectiveness of the therapy for Β-thalassemia

  K. Jiang, W. Y. Ma, I. Ortalli, G. Pedrazzi, X. Zhang, G. C. Izzi
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  ABSTRACT: In the present study, twenty-five samples of red blood cells (RBCs) and two samples of lyophilized serum, drawn from thirteen patients with -thanassemia major, have been examined by Mssbauer spectroscopy. All these patients undergo long-term therapy by regular blood transfusion and deferoxamine. The samples were obtained at the end of one cycle of treatments, before the successive blood transfusion. The results show, within the experimental errors, that the ferritin-like iron appears to be absent in the RBCs of the patients but it is still present in the serum.
  Hyperfine Interactions 01/1994; 91(1):859-863. · 0.21 Impact Factor
• Article: Thermal contraction of Silicone-based impression materials

  V. Fano, W. Y. Ma, I. Ortalli, K. Pozela
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  ABSTRACT: Linear thermal contraction of impression materials has been measured in the 40–18°C temperature range immediately after the polymerization shrinkage. Samples of 2 cm in length have been analysed by a scanned laser beam micrometer and the coefficient of thermal contraction has been calculated. Silicone-based specimens of different viscosities have been tested. The temperature-induced shrinkage has been compared with the time-dependent shrinkage.
  Il Nuovo Cimento D 11/1993; 15(12):1533-1538.
• Article: Dimensional stability of silicone-based impression materials.

  V Fano, P U Gennari, I Ortalli
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  ABSTRACT: This study attempts to demonstrate that the polymerization reaction is not the only factor that affects the shrinkage of silicone-based impression materials because evaporation of the constituents also contributes to the shrinkage. These factors can be evaluated by the study of time-dependent dimensional changes. This is shown both by chemical kinetics and by experimental testing of condensation and addition polymerizing impression materials with different viscosities. Comparison of the different materials shows that the two contributions, polymerization shrinkage, and evaporation shrinkage, can be assessed separately by analysis of the time-dependent shrinkage diagrams. The instability due to the polymerization reaction is complete after a few hours, but the contribution of the constituent evaporation, if present, can have a significant long-term role.
  Dental Materials 04/1992; 8(2):105-9. · 3.13 Impact Factor
• Article: Gamma-rays from Mössbauer sources: a low-dose approach to cancer therapy

  I. Ortalli, G. Pedrazzi, K. Jiang, X. Zhang, C. Carlo-Stella, V. Rizzoli
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  ABSTRACT: A new approach to cancer treatment using low-energy gamma-rays is discussed. Cultures of bone marrow mononuclear cells collected from normal donors and patients with chronic myelogenous leukaemia have been studied after the addition of hematin, at different concentrations, and irradiation by a Mössbauer gamma-ray source. Growth stimulation has been observed when hematin is added to normal bone marrow cultures, while growth inhibition is observed when hematin is added to leukaemic cultures. The effect becomes then more pronounced when hematin is used in combination with Mössbauer gamma-rays.
  Il Nuovo Cimento D 03/1992; 14(4):351-358.
• Article: Investigation of oxyhemoglobin in leukaemic patients

  I. Ortalli, G. Pedrazzi
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  ABSTRACT: Oxyhemoglobin from human normal adults and from leukaemic patients has been studied by Mössbauer spectroscopy to investigate the possibility to distinguish, through differences in the Fe2+ electronic structure, normals and leukaemic patients.
  Hyperfine Interactions 06/1990; 58(1):2377-2379. · 0.21 Impact Factor
• Article: Study of the Torino meteorite

  I. Ortalli, G. Pedrazzi
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  ABSTRACT: Mössbauer spectroscopy has been applied to the study of the Torino H6 meteorite. An identification of the principal components has been attempted.
  Hyperfine Interactions 06/1990; 57(1):2275-2278. · 0.21 Impact Factor