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M Bertolotto

Publications and source records attributed to M Bertolotto.

At least 55 records · Page 3Linked to original sources
PubMed1993

Analysis of echotexture of tendons with US.

To evaluate changes in echotexture of normal tendons at different frequencies and establish an anatomic correlation for fibrillar echoes, normal calcaneal tendons were examined in vitro at 7.5, 10, 13, and 15 MHz in calves (n = 8) and sheep (n = 6) and in vivo in humans (n = 8). Histologic correlation was obtained in vitro with 22-gauge needles that marked the position of echogenic fibrils under ultrasound (US) guidance. The human study group consisted of 25 patients with a clinical diagnosis of calcaneal tendon disease and 15 patients who underwent surgery for rupture of the Achilles tendon. At all four frequencies, normal tendons showed an internal network of fine parallel and linear fibrillar echoes that became more numerous and thinner as US frequency increased. These echoes were caused by specular reflections at the interface between collagen bundles and endotendineum septa. In patients, tendons showed a variety of basic changes in fibrillar pattern: increased fibrillar thickness (33 patients), interruption (17 patients), fragmentation (12 patients), and disappearance of echotexture (15 patients). It is concluded that US holds promise in detection of minimal changes in tendinous structure.

Achilles Tendon↗
PubMed1992

[Color-Doppler echography of the testis. Study technique and vascular anatomy].

Color-Doppler sonography has recently made it possible to image scrotal vascularity non-invasively. This study was undertaken to determine the normal color-Doppler appearance and distribution of scrotal vessels and to define the technical principles of the examination. Color-Doppler imaging was effective in detecting both funicolar and testicular vessels. Among these, capsular (25/25), trans-testicular (10/25), centripetal and recurrent (25/25) arteries were easily identified. Waveforms analysis allowed to differentiate veins from arteries within testis and to distinguish (8/10) supratesticular (high impedance pattern with absent diastolic flow) from intratesticular arteries (low impedance pattern with high levels of diastolic flow). The optimal color depiction of scrotal vascularity needed the appropriate selection of several imaging parameters to increase detection of low-velocity, low-volume flows within the small testicular vessels. Such parameters included: PRF (ranging 1500 to 600 Hz), wall filters (ranging 25 to 50 Hz), color gain (maximized for optimal sensitivity while avoiding excessive color noise), color vs. echo priority (ranging 70 to 90%) and color persistence (adjusted to high values). In conclusion, color-Doppler imaging is capable of reliably showing the normal anatomy of testicular vessels. It could make a reliable substitute for scintigraphy and continuous wave Doppler in diagnosing scrotal conditions that alter blood flow.

Adult↗
PubMed1991

Changes in DNA superhelical density monitored by polarized light scattering.

Linear and circular lambda-DNA at different ethidium bromide concentrations have been studied by means of polarized light scattering, namely the S14, S34, S33 and S13 elements of Mueller matrix. While S33 at low angle appears well correlated with the total light scattering evaluated by optical density measurements at 632.8 nm for linear and circular DNA of the same mass, the magnitude and slope of the S14, S34 and S13 signals display significant changes for the circular lambda-DNA depending on the degree of negative superhelical density as induced by the different ethidium bromide concentrations. At the same time, for linear lambda-DNA the signal remains invariant, making explicit for the differential scattering of polarized light the possibility to obtain additional information by its angular dependence. Strikingly also the effect of 0.2% glutaraldehyde versus ethanol fixation on the native lambda-DNA structural properties appears to confirm earlier findings by other well-established probes. Results are discussed in terms of first physical principles and of their potential bearings towards our understanding of the mechanism controlling gene expression.

Bacteriophage lambda↗
PubMed1991

Polarized light scattering of nucleosomes and polynucleosomes--in situ and in vitro studies.

Nucleosomes, chromatin and nuclei, extracted from rat hepatocytes, are studied by a new "in house" experimental configuration which measures circular intensity differential scattering (CIDS) and other elements of the polarized light scattering matrix. The Mueller matrix elements, S14 and S34, that are related to the geometric parameters of the superhelical arrangement of polynucleosomes point to the existence of a quaternary structure at low ionic strength for chromatin prepared by the cold-water method, which is lost by shearing, and is not found in the soluble chromatin prepared through the nuclease method. Only salt addition to a final concentration of 5 mM MgCl2, 150 mM NaCl and 10 mM Tris HCl (pH 7) yields a sizeable (S14 + S34) signal in the latter chromatin, which is however still different from the corresponding signal of native nuclei and of "cold-water" chromatin. Comfortingly, the (S14 + S34) signal from isolated nucleosomes is consistently very low (nearly zero) as predicted by multiple dipole simulation within the framework of classical electrodynamics. Results are discussed in terms of the topological constraints present in the native long chromatin fiber, which are lost after limited nuclease digestion and after shearing.

Animals↗
PubMed1988

Nuclear architecture, intranuclear DNA distribution, and nuclease digestion.

G0, G1, and mammalian cells and nuclei were shortly digested with either micrococcal nuclease or DNAse I, both before and after mild fixation, either before (G0) or after (G1) partial hepatectomy. Cells were Feulgen stained and examined by high resolution light microscopy. In metabolically active G1 nuclei, intranuclear DNA appears organized at least in two distinct domains, whereby the highly dispersed one is large enough to be detected at the resolution of the light microscope and appears preferentially attacked by limited DNAse I digestion. The action of the enzyme is readily apparent only in the nuclei that are first digested and then fixed. Spectroscopic characterization of the same nuclei reveals that the fixation causes a sizeable removal of proteins, mostly in the soluble chromatin subfraction. Results are discussed in terms of two control levels for gene expression and for higher order DNA structure.

Animals↗
PubMed1985

[Ferritin, CEA and TPA as tumor markers in breast neoplasms].

In order to assess the sensitivity and specificity of Ferritin, CEA and TPA as neoplastic markers in breast carcinomas, 91 patients all classified according to the TNM-UICC system were studied in a cancer clinic. The results of the analyses indicate that ferritin is apparently only influenced by the presence of metastatic neoplasias and that greater sensitivity is obtained if all three markers are employed simultaneously.

Antibody Affinity↗