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Biomedical subjects

M Bianchi

Publications and source records attributed to M Bianchi.

At least 343 records · Page 19Linked to original sources

The biological effect of very high energy hadrons.

The meristems of Vicia faba bean roots were irradiated at different depths in water in a 250 GeV/c positive hadron beam from the CERN Super Proton Synchrotron (SPS). The growth during the 10 days following irradiation was determined and compared with results obtained from 60Co gamma-ray exposures. The data indicate a Relative Biological Efficiency (r.b.e.) near to one, independent of the contribution of secondaries to the dose. However, some anomalies in the radiation response of the irradiated beans were noted.

Cobalt Radioisotopes↗

Erythrocyte superoxide dismutase, catalase and glutathione peroxidase activities in beta-thalassaemia (major and minor).

The 'antioxidant' enzymes superoxide dismutase (SD), catalase and glutathione peroxidase (GSH-Px) were found greatly elevated in red blood cells of subjects with beta-thalassaemia minor and similar to normal values in red blood cells of subjects with beta-thalassaemia major. These findings allows us to speculate that red cells in beta-thalassaemia minor react to the increased oxidant threat with augmented antioxidant enzyme activities. The normal levels of antioxidant enzymes in beta-thalassaemia major seem to be due to the presence of normal red cells owing to multiple transfusions.

Catalase↗

Superoxide dismutase, catalase and glutathione peroxidase activities in maternal and cord blood erythrocytes.

The "antioxidant" enzymes superoxide dismutase, catalase and glutathione peroxidase were assayed in a biological model with low oxygen tension (red cells from cord blood of newborn infants). Catalase and glutathione peroxidase activities in red cells of newborns were significantly lower when compared with their mothers and with normal controls. In contrast, superoxide dismutase activity was unchanged. Thus, normal activities of superoxide dismutase seem to be necessary in order to protect red blood cells from superoxide radicals during foetal life, while even low activities of catalase and glutathione peroxidase are sufficient to protect red blood cells from hydrogen peroxide. No correlation was found between the "antioxidant" enzyme activities present in cord blood erythrocytes and the bilirubin concentrations during the first days of life.

Adult↗

RBE and OER values of negative pion beams from growth inhibition of Vicia faba roots.

Two pion beams of different momentum width have been used to expose meristems of Vicia Faba roots under aerobic and hypoxic conditions. The measurements of the resulting 10 days growth inhibition after exposures at various locations on the pion beam axes have been made and RBE and OER values evaluated for 50% effects compared to 60Co gamma-rays. The results have been related to the fractional doses from star products defined by telescope measurements of stopped pions along the same beams. It has been found that the RBE value increases with the fractional "star dose" up to a maximum after which the RBE decreases. The OER values, however, were found to decrease with increasing "star dose" fraction rather rapidly after which it was found to be independent of the "star dose" contribution.

Dose-Response Relationship, Radiation↗

Neurogenic activity--angiotensin II interaction during the development and maintenance of renal hypertension in the rat.

1. Pentolinium tartrate (a ganglionic blocker) was injected in conscious rats during the early and late phases of two-kidney renal hypertension produced by aortic ligation. 2. In the early phase ( 5 days after aortic ligation), ganglionic blockade resulted in a decrease in blood pressure equal to that obtained in normotensive rats. Later, at days 12 and 40, for equally severe hypertension, ganglion blockade resulted in a greater decrease in blood pressure. 3. A 30 min infusion of [Sar1, Ala8]angiotensin II during the pentolinium-induced nadir in blood pressure resulted in a further decrease in blood pressure at day 5. Later, at days 12 and 40, this effect was smaller. 4. A 300 min infusion of [Sar1, Ala8]angiotensin II normalized the blood pressure in hypertensive rats at day 40. This delay response may be secondary to a central effect of the antagonist, reducing neurogenic tone or peripheral antagonism of locally generated angiotensin II in the blood vessel walls. 5. At day 40, removal of the small left kidney resulted in a greater decrease in blood pressure. This suggests the presence of a renal factor other than renin in the chronic phase of this hypertension.

Angiotensin II↗