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G Giraudi

Publications and source records attributed to G Giraudi.

29 records · Page 2Linked to original sources
PubMed1983

[Studies on iodine exchange in thermal therapy with salsobromoiodic water].

We have attempted a quantitative evaluation of the iodine taken in with the thermal waters from Salsomaggiore during therapeutic bathing, inhalation (dry and damp spray), or ingestion. For this purpose to 127I we have applied the metabolic parameters obtained through a 131I inhalation test and a 125I ingestion test. Of the iodine inhaled by aerosol 45% becomes exhaled; by 24 hours 2% is in the serum and in the extra-thyroid area of iodine distribution, 16% in the thyroid, 16% in the urine. By adding the amount of iodine exhaled to that found in the metabolic cycle of iodine, we find that about 21% of the inhaled iodine is still missing. This amount is trapped in the respiratory tract from where it disappears only very gradually. At the end of the 24 hours, therefore, in the metabolic cycle of the iodine we find 34% of that inhaled, whereas we find 87% of that ingested. The level of iodine in the serum reached in thermal therapeutic inhalation, never stays at a level which might alter the functioning of a normal thyroid. The amount of inhaled iodine which is excreted with the urine is usually eliminated during the first excretions. Experimental studies suggest that the iodine taken in during bathing in the thermal-pools mainly comes from iodine released from the water through the addition of hypochlorites, and is then inhaled through breathing the air just above the water.

Balneology↗
PubMed1983

Kinetics of the reaction between testosterone and antitestosterone antiserum.

In order to characterize from a kinetic viewpoint the antibody population mainly involved in the binding of testosterone by its homologous antiserum, the kinetics of the association reaction between [1,2,6,7-3H]-testosterone and rabbit antiserum anti-testosterone-3-(O-carboxymethyl)oxime-bovine serum albumin (Ab R2603-1) was followed at pH 7.4 and at constant ionic strength, at temperatures ranging from 2 degrees C to 37 degrees C and at concentration near to work conditions for testosterone radioimmunoassay; dextran coated charcoal suspension was used for the bound/free separation. In the examined concentration range, the observed kinetics trends can be explained by assuming the existence of two classes of antibody binding sites, Ab1 and Ab2. The kinetics of the dissociation reaction of the testosterone-antibody complex was also followed after the addition of a large excess of unlabeled testosterone. At 22.0 degrees C, association and dissociation rate constants are 2.1.10(7) s-1M-1 and 3.7.10(-3) s-1, respectively, for the Ab1 class of antibody binding sites, and 3.6.10(6) s-1M-1 and 7.0.10(-4) s-1 for the Ab2 class. Equilibrium constants obtained from kinetic data were very similar for both classes of antibody binding sites and in good agreement with the equilibrium values obtained from linear Scatchard plot. The order of magnitude of the second order rate constants and the high activation enthalpy for the forward and reverse reaction suggest a mechanism more complex than a simple second order.

Animals↗
PubMedDate not supplied

Thyroid hormones in tissues from human embryos and fetuses.

This study was intended to quantify T3 and T4 in various human tissues at different stages of gestation as a contribute in the evaluation of the role of thyroid hormones in fetal development, particularly before the maturation of fetal thyroid function. Moreover, for a better comprehension of the influence of thyroid hormone status in tissues, the study was extended to adults. Embryonic specimens were obtained from voluntary abortions between 6 and 12 weeks of gestation, fetal and neonatal specimens from fetuses and neonates between 15 and 36 weeks of gestation after spontaneous abortion or stillbirth, and adult specimens from men (age range: 45-65 years) after death for cardiovascular diseases. Thyroid hormones were measured by the method of Gordon and coworkers. In embryos T3 and T4 were measured in limbs, carcasses, brain and liver: considering all values measured in the period 9-12 weeks, a mean concentration of 0.11 ng/g for T3 and 1.28 ng/g for T4 was obtained. In pooled limbs of 6-8 weeks T3 was barely measurable (0.01 ng/g). In the carcasses there was an increase in T3 and T4 concentrations of 40 and 20 times respectively from the 9th to the 12th week, when thyroid follicles organization takes place. In fetuses and adults T3 and T4 were measured in brain, heart, kidney, liver, lung, skeletal muscle and skin (mean concentrations: 0.86 ng/g for T3 and 7.44 ng/g for T4 in fetuses and neonates; 1.36 ng/g for T3 and 12.75 ng/g for T4 in adults). Hormones concentration increased with gestational age; the T3/T4 ratio increased until 22-24 weeks, when the prevalent increment in T4 occurs. T3 concentration up to 30 weeks was generally higher in tissues than in cord serum of the corresponding age. During the last month of gestation T3 increment was faster in serum. T4 level was always predominant in serum. In conclusion, T3 and T4 have been detected in the limbs of embryos before the onset of thyroid hormone secretion. Concentrations were 1/150 and 1/70, of the normal maternal blood values respectively. It is conceivable that these hormones are of maternal origin, and the question of whether such small quantities may play a role in fetal development is open.

Brain↗
PubMedDate not supplied

Functionalized biopolymers as soluble macromolecular chelating agents.

Two different conjugates of bovine serum albumin (BSA) with lysine and a derivative of imidazole have been synthesized to obtain watersoluble macromolecules with binding properties against bivalent transition metal ions. Syntheses have been carried out using the 60 aminogroups or the 99 carboxylic groups on BSA for the coupling reactions, with such molar ratios able to produce highly substituted BSA. The skill of each conjugate to bind metal ions in aqueous medium was studied through the use of titration curves with some metal ions, characterized by a good affinity for the free ligand. Both the conjugates allow us to recover a high number of metal ions per protein molecule, close to the number of ligand molecules on the BSA surface in the case of the lysine conjugate, whereas in the case of the imidazole conjugate M3L complexes are performed.

Biopolymers↗
PubMedDate not supplied

The complexation of mercury (II) and organomercurial compounds by 8-hydroxyquinoline-bovine serum albumin conjugates.

The complexing properties of conjugates between 8-hydroxyquinoline and bovine serum albumin (Ox-BSA) towards inorganic and organic mercury were studied. Two Ox-BSA conjugates (different substitution ratio) were prepared and their complexing properties were studied. Through the use of titration curves with mercury (II), methylmercury and ethylmercury an evaluation of the complex stoichiometry and stability was obtained, showing that Ox-BSA has good affinity for all investigated mercuric compounds and that the stability increases in the order: Hg (II) < CH3Hg+ < C2H5Hg+, whatever conjugate is considered. Complexes show a stoichiometry of 1:1 between mercury and 8-hydroxyquinoline residues, except with the high substituted conjugate and Hg2+ ion. The skill of the high substituted conjugate to bind inorganic and organic mercury in the presence of NaCl was also studied. Organic mercuric complexes do not show significant modification due to NaCl. Nevertheless, considering inorganic mercury, the number of retained metal ions per protein molecule increases if the NaCl concentration becomes higher than 0.1 M, probably because at high NaCl concentrations 1:1 complexes between mercury and 8-hydroxyquinoline are preferred to 1:2 complexes.

Animals↗