Biomedical subjects

M Lattuada

Publications and source records attributed to M Lattuada.

12 recordsLinked to original sources

PubMed2005

Modelled microgravity does not modify the yield of chromosome aberrations induced by high-energy protons in human lymphocytes.

The aim was to evaluate the effect of modelled microgravity on radiation-induced chromosome aberrations (CAs). G0 peripheral blood lymphocytes were exposed to 60 MeV protons or 250 kVp X-rays in the dose range 0-6 Gy, and allowed to repair DNA damage for 24 h under either normal gravity or microgravity modelled by the NASA-designed rotating-wall bioreactor. Cells were then stimulated to proliferate by phytohaemagglutinin (PHA) under normal gravity conditions and prematurely condensed chromosomes were harvested after 48 h. CAs were scored in chromosomes 1 and 2 by fluorescence in-situ hybridization. Proliferation gravisensitivity was examined by cell growth curves and by morphological evaluation of mitogen-induced activation. Cell replication rounds were monitored by bromodeoxyuridine labelling. Modelled microgravity markedly reduced PHA-mediated lymphocyte blastogenesis and cell growth. However, no significant differences between normal gravity and modelled microgravity were found in the dose-response curves for the induction of aberrant cells or total interchromosomal exchange frequency. Rotating-wall bioreactor-based microgravity reproduced space-related alterations of mitogen stimulation in human lymphocytes but did not affect the yield of CAs induced by low-linear energy transfer radiation.

Cell Proliferation↗

PubMed2005

Impact of pyrexia on neurochemistry and cerebral oxygenation after acute brain injury.

BACKGROUND: Postischaemic pyrexia exacerbates neuronal damage. Hyperthermia related cerebral changes have still not been well investigated in humans. OBJECTIVE: To study how pyrexia affects neurochemistry and cerebral oxygenation after acute brain injury. METHODS: 18 acutely brain injured patients were studied at the onset and resolution of febrile episodes (brain temperature > or = 38.7 degrees C). Intracranial pressure (ICP), brain tissue oxygen tension (PbrO2), and brain tissue temperature (Tbr) were recorded continuously; jugular venous blood was sampled intermittently. Microdialysis probes were inserted in the cerebral cortex and in subcutaneous tissue. Glucose, lactate, pyruvate, and glutamate were measured hourly. The lactate to pyruvate ratio was calculated. RESULTS: Mean (SD) Tbr rose from 38 (0.5) to 39.3 (0.3) degrees C. Arteriojugular oxygen content difference (AJD(O2)) fell from 4.2 (0.7) to 3.8 (0.5) vol% (p < 0.05) and PbrO2 rose from 32 (21) to 37 (22) mm Hg (p < 0.05). ICP increased slightly and no significant neurochemical alterations occurred. Opposite changes were recorded when brain temperature returned towards baseline. CONCLUSIONS: As long as substrate and oxygen delivery remain adequate, hyperthermia on its own does not seem to induce any further significant neurochemical alterations. Changes in cerebral blood volume may, however, affect intracranial pressure.

Acute Disease↗

PubMed2003

Good short-term agreement between measured and calculated tracheal pressure.

BACKGROUND: Tracheal pressure (P(tr)) is required to measure the resistance of the tracheal tube and the breathing circuit. P(tr) can either be measured with a catheter or, alternatively, calculated from the pressure-flow data available from the ventilator. METHODS: Calculated P(tr) was compared with measured P(tr) during controlled ventilation and assisted spontaneous breathing in 18 healthy and surfactant-depleted piglets. Their lungs were ventilated using different flow patterns, tidal volumes (V(T)) and levels of positive end-expiratory pressure. RESULTS: In terms of the root mean square error (RMS), indicating the average deviation of calculated from measured P(tr), the difference between calculated and measured P(tr) was 0.6 cm H(2)O (95%CI 0.58-0.65) for volume-controlled ventilation; 0.73 cm H(2)O (0.72-0.75) for pressure support ventilation; and 0.78 cm H(2)O (0.75-0.80) for bi-level positive airway pressure ventilation. CONCLUSION: The good agreement between calculated and measured P(tr) during varying conditions, suggests that calculating P(tr) could help setting the ventilator and choosing the appropriate level of support.

Air Pressure↗

PubMed2001

Estimation of fractal dimension of colloidal gels in the presence of multiple scattering.

Colloidal dispersions of fluorinated polymer particles with a refractive index very close to that of water, have been used to investigate the effect of multiple scattering on the estimated fractal dimension of colloidal gels, at high-particle volume fractions. The extent of multiple scattering was varied by using cuvettes of different internal diameters, from 3 to 18 mm. Three gelation systems with different sizes and volume fractions of primary particles have been characterized by static light scattering SLS. The obtained results indicate that multiple scattering affects only the magnitude of the scattered radiation, but not the estimated fractal dimension of the gels. This result confirms the conclusion of the theoretical study reported by Chen et al. [Phys. Rev. B 37, 5232 (1988)]. As a further confirmation, the same gels have been formed in a specially designed cell, with only 0.1 mm thickness (where multiple scattering is negligible) and characterized using small-angle neutron scattering (SANS). It is found that the fractal dimension estimated from SANS measurements, without multiple scattering, is the same as that estimated from SLS measurements, in the presence of substantial multiple scattering.

Journal Article↗

PubMed1995