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Biomedical subjects

G Albertini

Publications and source records attributed to G Albertini.

At least 37 records · Page 2Linked to original sources

Thermodynamic and structural effects of propranolol on DPPC liposomes.

Some thermodynamic and structural aspects of propranolol-DPPC liposomes interaction were investigated by DSC and X-ray diffraction: the lamellar arrangement of the lipid matrix remains intact even at high concentrations of the drug (until 1:1 drug/lipid molar ratio). However, the bilayer thickness increases significantly and the chains become perpendicular to the lamellar planes, for increasing drug content. At still higher propranolol concentrations a hexagonal phase occurs followed by a lamellar phase, in which the liposomes are destroyed. Moreover, the presence of propranolol has been found to impart fluidity to the lipid matrix.

1,2-Dipalmitoylphosphatidylcholine↗

Studies of structural modifications induced by gamma-irradiation in distearoylphosphatidylcholine liposomes.

An investigation of the structural and thermodynamical modifications induced by gamma-irradiation in model membranes is reported. Differential scanning calorimetry and X-ray diffraction were used to study the different phases and associated transitions of distearoylphosphatidylcholine multilamellar liposomes after 60Co gamma-irradiation. Changes were observed in the shape of the calorimetric peaks and in the corresponding phase transition temperatures. In particular a shoulder was observed at about 20 kGy. The three phases characteristic of lecithins with identical acyl chains were detected also for the highest radiation dose. The formation of lysolecithin and stearic acid upon phospholipid degradation was observed. The lysolecithin concentration increases as a function of irradiation dose, until a saturation value is reached at 40 kGy. These results correlate quite well with those obtained for interlayer and interchain distances and for the width of the main phase transition calorimetric peak. At the highest dose (approximately equal to 80 kGy) cross-linked adjacent radicals and other molecular species are also formed. Appreciable differences, and some similarities, in the behaviour of DSPC and DPPC liposomes under gamma-irradiation were observed.

1,2-Dipalmitoylphosphatidylcholine↗

Clinical pharmacology of tritoqualine: a comparative study against dexchlorpheniramine in allergic rhinitis.

The effect of tritoqualine on seasonal allergic rhinitis caused by grass pollen was compared to that of dexchlorpheniramine maleate (DCPM) in 21 patients randomly allocated into two parallel groups. There were rapid improvements of all symptoms considered after treatment with either tritoqualine or DCPM. A significant reduction of plasma histamine concentrations was observed during the treatment with tritoqualine whereas no modification occurred with DCPM. Finally, it was shown that tritoqualine did not modify reaction times to visual and auditive stimuli whereas DCPM induced a significant slowing-down of the reaction time to visual stimuli. From this pilot study tritoqualine appears to have the same efficacy for the treatment of seasonal allergic rhinitis as classic anti-H1 antihistamines, but without central nervous system side-effects.

Adolescent↗

X-ray diffractometry and calorimetry studies of structural modifications induced by gamma-irradiation in phosphatidylcholine multilamellar liposomes.

Experimental results are reported on structural and thermodynamic modifications induced by gamma-irradiation in model membranes. Differential scanning calorimetry (DSC) and X-ray diffraction were used to study the different phases and associated transitions of dipalmitoylphosphatidylcholine after 60Co gamma-irradiation. Changes were observed in the shape of calorimetric peaks and in the corresponding enthalpy. The repetition distance of the layers increases while the distances related to the aliphatic chains decrease as a function of gamma-irradiation time. Moreover, an increase in the hexagonal symmetry with increasing dose was detected. No disappearance of a pre-transition was detected even at high doses.

Calorimetry↗