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Biomedical subjects

G Schiliro

Publications and source records attributed to G Schiliro.

At least 37 records · Page 2Linked to original sources

Population structure of Sicily: beta-thalassemia and HbS.

The population structure of two alleles with similar characteristics, HbS and beta-thalassemia, was studied in the same area in Sicily. It was observed that beta-thalassemia has uniform frequencies over the island, and that HbS shows a South-North cline. A singularity exists for HbS in the town of Butera, where the frequency of the S gene is six times higher than the island average. It was suggested that HbS entered Sicily from Greece (or directly from North Africa) when the beta-thalassemia allele was already established in the Island.

Alleles↗

Structure and expression of two beta genes in a beta thalassemia homozygote.

Two beta globin gene alleles have been cloned and characterized from a patient with beta + thalassemia. Both beta genes have single base mutations in the small intervening sequence (IVS 1); one 6 nucleotides and the other 110 nucleotides from the 5' end of IVS 1. Both genes lead to abnormal splicing of beta globin mRNA precursors when expressed in HeLa cells. Despite the fact that both alleles produce some normal beta globin mRNA transcripts, the patient has clinically severe beta + thalassemia (Cooley's anemia).

Base Sequence↗

Beta-chain contact sites in the haemoglobin S polymer.

The amino acid residues involved in the areas of contact that stabilise the haemoglobin S polymer fibre seem to be the same ones that stabilise the basic unit of the deoxyhaemoglobin S crystal: the Wishner-Love double strand. The haemoglobin S fibre is probably formed by a unique packing of these double strands.

Binding Sites↗

Sickle cell disease in Sicily.

The chemical and physical properties of haemoglobin S derived from homozygotes for this haemoglobin in Sicily were examined, as well as some erythrocytic characteristics. Sicilian Hb S was identical to that found in USA black patients in electrophoretic mobility on both starch and citrate agar media, solubility, mechanical precipitation rate of oxyhaemoglobins, and minimum gelling concentration, as well as by peptide mapping and amino-acid analysis of all beta-chain peptides. Taken together with the presence in Sicily of African blood group markers and certain historical considerations, it seems clear that the source of Hb S in Sicily is Africa. While the clinical severity in nine Sicilian children did not seem remarkably different from the disease in the USA, the most severe and fatal complications were not seen. Mean Hb F Was 10.5% and 2,3-diphosphoglycerate (2,3-DPG) values were higher in Sicilian homozygotes than in black USA counterparts (21.79 mumol/g Hb vs 15.16). Red cell AT values were also slightly higher in Sicilian patients. The presence of concomitant thalassaemia was excluded by both family studies and globin chain synthetic ratios. In conclusion, haemoglobin S in Sicilian homozygotes is identical to Hb S found in USA blacks. Although the severity of the disease seems quite similar in both groups of patients, other erythrocytic properties were found to be different. Whether these factors influence severity remains to be elucidated.

Adenosine Triphosphate↗

Haemoglobin Lepore Boston-Washington in Sicily: clinical, haematological, and biosynthetic studies.

In the south-east of Sicily 23 children from 14 unrelated families have been diagnosed as suffering from haemoglobin Lepore. Such a high incidence shows that Sicily is an important focus of haemoglobin Lepore. The results of haematological and biosynthetic studies in 18 carriers of Hb Lepore and in five double heterozygotes for Hb Lepore and beta-thalassaemia are presented. In the carriers the haematological and biosynthetic data are compared with carriers of beta-thalassaemia, while the five double heterozygotes are compared with beta o- and beta +-thalassaemia major subjects. In the carriers of Hb Lepore no synthesis of delta beta-chains was observed in peripheral blood cells; in fact we found a peak in the bone marrow. Double heterozygotes with circulating nucleated red cells showed delta beta-chain synthesis in peripheral blood.

Bone Marrow↗

Alpha thalassaemia in Sicily: haematological and biosynthetic studies.

Eight Sicilian patients with Hb H disease and their families have been studied. The standard haematological tests and the alpha/beta chain synthesis ratios showed significantly different results in the patients with Hb H disease as compared with alpha thalassaemia carriers, except for Hb A2 values. There was no significant difference in the mean RBC, MCV, Hb A2, Hb A1 and Hb F of alpha thalassaemia carriers compared with normal controls. On the contrary significant difference was found between the mean alpha/beta chain synthesis ratio of alpha thalassaemia carriers and that of the normal controls; however, the extensive overlapping of alpha/beta values between these two conditions make this parameter insufficiently discriminant. No correlation was found between MCV, MCH, RBC and alpha/beta chain synthesis ratio in patients with alpha thalassaemia trait, suggesting that the ratio cannot be used to distinguish between carriers of a mild gene ('silent' carrier) and carriers of the more severe alpha thalassaemia gene. A possible genetic model for alpha thalassaemia in Sicily is presented.

Adolescent↗

Glucose-6-phosphate dehydrogenase deficiency in Sicily. Incidence, biochemical characteristics and clinical implications.

This report deals with the incidence, type and clinical implications of G6PD deficiency in Sicily. Of 3347 male subjects examined, 56 were deficient in G6PD. They were distributed throughout the island. The G6PD levels in RBC were almost zero; in leukocytes, platelets and saliva they were found to be 26%, 18% and 16%, respectively, of controls. The Michaelis constant for NADP and G6PD was lower than for controls. Conversely, the utilization of the analogous Ga16P and 2dG6P was higher. The thermostability of the enzyme was lower and the pH optima (6.5 and 9.5) were different from the controls. An identical electrophoretic pattern was found both in normal and deficient subjects. This pattern is superimposable on that described as Mediterranean variant. The analysis among 270 subjects admitted to our Clinic with hemolysis due to G6PD deficiency demonstrated that the most frequent disease is favism, followed by neonatal jaundice, while hemolysis due to drugs is very rare. Ingestion of fresh fava beans was the most frequent cause of favism, but cases occurred after breast feeding and inhalation of pollen.

Adolescent↗

Lymphocyte changes in beta-thalassaemia major.

Lymphocyte subpopulations were studied in 20 hypertransfused patients with beta-thalassaemia major, some of whom had been splenectomised. B-lymphocytes were normal but T-lymphocytes were decreased in all patients. The T-cell count was lower in the splenectomised patients than in the nonsplenectomised ones. In the former, the active rosette-forming lymphocytes were also diminished, but the difference was not significant. In all patients the percentage of null cells was greater and the activity of K-cells increased compared with controls.

Adolescent↗

Quantitation of human globin chain synthesis by cellulose acetate electrophoresis.

We have developed a method for the separation and quantitation of human alpha-, beta-, and gamma-globins utilizing cellulose acetate electrophoresis. The relative rates of synthesis of globin chains in reticulocytes in peripheral blood is determined by: (i) incubating intact cells with [35S]methionine; (ii) preparing globin from the hemolysates; (iii) performing electrophoresis of the globin on cellulose acetate strips; and (iv) autoradiography or direct determination of the radioactivity incorporated into each globin chain. The method is simple and rapid, requires only small amounts of hemolysate (30 micrograms of globin), and provides excellent resolution and reproducible quantitation of alpha-, beta A-, beta S-, and gamma-globin chains for up to 24 peripheral blood samples at one time. Measurements by this method in patients with thalassemia variants and sickle-cell disorders correlate well with analysis of the same samples by carboxymethyl cellulose chromatography. This methodology may permit more widespread analysis of globin synthesis in the thalassemia syndromes and may also be useful in the analysis of globins synthesized from human globin mRNA in cell-free systems.

Anemia, Hemolytic, Autoimmune↗