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Biomedical subjects

G Ricco

Publications and source records attributed to G Ricco.

At least 55 records · Page 3Linked to original sources
PubMed1984

The oxygen affinity of normal human whole blood measured by double tonometry. II. pH-depending Bohr effect and DPG.

Following another preliminary work on the whole blood oxygen affinity, the Authors have found in this occasion normal values of the pH-depending Bohr effect in healthy subjects of both sexes and different age. Furthermore, the Hb decreasing causes in these cases also a P50 increasing which is mediated by raised DPG levels. However, while in the anemias this effect is constant, many exceptions have been found in physiological conditions. Since these ones have been mainly detected at the maximal DPG levels, the phosphate could modify the affinity not only as allosteric effector, but also by acting on pH and related equilibria as non diffusible free anion. These interferences are difficult to be calculated and often could disturb notably a correct use of the common mathematical model which describes the oxygenation.

Adolescent↗
PubMed1980

gamma chain composition in five Italian newborns heterozygous for Hb F Malta G gamma-117 His leads to Arg.

The percentage of Hb F Malta G gamma-177 His replaced by Arg and the gamma chain composition have been evaluated at birth and at different times after birth in five Italian newborns heterozygous for this variant. The percentage of Hb F Malta ranged at birth from 24% to 31% of the total Hb F, while the average G gamma/A gamma chain ratio was about 7/3, overlapping the values observed in normal newborns. T gamma chains were detected in three out of five newborns, with a percentage of about 10% of the total Hb F. After birth the Hb F Malta declined faster than the total Hb F; thus, the Hb F decrease during the first 45 d of life is mainly due to the switch-off of the G gamma locus containing the Hb F Malta gene.

Aging↗
PubMed1979

Electrophoretic separation of A gamma and G gamma human globin chains in Nonidet P-40.

Electrophoresis in cellulose acetate in the presence of 3% Nonidet P-40 can resolve two neutral genetic variants, A gamma and G gamma human fetal globin chains. The ratio of these two chains, determined by densitometry of the electrophoretic strips, is in excellent agreement with the Gly-Ala ratio obtained by chemical analysis of the cyanogen bromide fragment gamma CB3. It is suggested that the detergent binds preferentially to the hydrophobic amino acid segment 133-141 in the A gamma chain, thus masking either a Lys or an Arg residue at the two extremes.

Electrophoresis, Cellulose Acetate↗
PubMed1979

Human T gamma globin chain is a variant of A gamma chain (A gamma Sardinia).

Isoelectric focusing, cellulose acetate electrophoresis, and carboxymethylcellulose chromatography in the presence of Nonidet P-40 allow the separation of pure gamma chains into two fractions. Amino acid analysis of their cyanogen bromide fragment 3 (gamma CB3) identifies these fractions as the separated G gamma (Gly-136) and A gamma (Ala-136) globin chains. Fingerprint and amino acid analyses of the gamma Tp9 tryptic peptide from the purified A gamma and G gamma fractions from two different patients demonstrate that the commonly occurring gamma Sardinia variant (gamma 75 isoleucine leads to threonine), also known as T gamma chain, has alanine in position 136. From this analysis we suggest that the T gamma gene is an allele of the A gamma locus (A gamma Sardinia) rather than a third gamma locus.

Alleles↗
PubMed1978

Interaction between Hb Hasharon and alpha-thalassemia: an approach to the problem of the number of human alpha loci.

We report the case of an Italian infant girl from Polesine (Po delta region in northern Italy) who was heterozygous for Hb Hasharon and alpha-thalassemia, did not synthesize any normal HbA, and had 3% HbH on electrophoresis. Hematologic and biosynthetic studies on Hb Hasharon carriers of the propositus' family suggest the possibility that the Hb Hasharon gene is linked to an alpha-thalassemia gene. On the other hand, in the Askenazy carriers of Hb Hasharon, Hb Harsharon is probably linked to a normal alpha gene. In comparing Hb Hasharon's behavior with that of other alpha variants, particularly HbG Philadelphia, frequent recombinations between alpha structural genes were suggested. The possible identity between the single alpha locus and the alpha2-thalassemia genotype is discussed.

Female↗
PubMed1976

Significance of a new type of human fetal hemoglobin carrying a replacement isoleucine replaced by threonine at position 75 )E 19) of the gamma chain.

A new type of hemoglobin F, in which isoleucine in position 75 (E 19) of the gamma chain is replaced by a threonine residue, has been found in 29 out of 32 homozygotes for beta thalassemia. The amount of this hemoglobin ranges from traces to 40% of the total Hb F. The same gamma75 Thr chain is also present in the Hb F of 40% of normal newborns and premature infants examined, of one 14-week-old fetus and in one out of 3 patients with aplastic anemia and raised levels of Hb F. Our results strongly suggest that the synthesis of this new chain is under the control of a gamma gene nonallelic with those coding for Agamma and Ggamma chains.

Adult↗
PubMed1975

The relationship between anemia, fecal stercobilinogen, erythrocyte survival, and globin synthesis in heterozygotes for beta-thalassemia.

Erythrocyte survival, fecal stercobilinogen, and the alpha/beta-chain synthesis ratio in recticulocytes and bone marrow (six cases only) were determined and related to the hemoglobin levels in ten heterozygous carriers of beta-thalassemia with different degrees of anemia. Erythrocyte survival values were low, though not related to the degree of anemia, whereas stercobilinogen values and changes in the peripheral blood alpha/beta-chain ratios were so correlated. In the case of bone marrow, on the other hand, the ratio between alpha-chain and beta-chain synthesis was virtually 1, irrespective of the degree of anemia. It is suggested that the severity of anemia in heterozygous carriers is independent of peripheral hemolysis and entirely attributable to destruction of erythroblasts within the marrow.

Anemia↗