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M B Colombo

Publications and source records attributed to M B Colombo.

8 recordsLinked to original sources
PubMed1994

Glucose phosphate isomerase (GPI) "Morcone": a new variant from Italy.

Here we report the 4th Italian case of glucose phosphate isomerase (GPI) deficiency. The propositus is a young man suffering from chronic haemolytic anaemia since birth with occasional transfusion requirement. Biochemical characterization of the defective enzyme revealed increased affinity for F-6-P, decreased affinity for G-6-P and marked thermoinstability. Electrophoretic mobility appeared normal. GPI from both parents showed similar but less pronounced biochemical alterations. The variant described here seems to be different from those previously reported. Thus, we propose the provisional name of GPI "Morcone".

Adult↗
PubMed1993

Iron status in red cell pyruvate kinase deficiency: study of Italian cases.

We investigated the iron status of 33 pyruvate kinase (PK) deficient patients, most of the cases reported in Italy. Serum ferritin (SF) was higher than the upper limit of the range of matched controls in 15/25 (60%) non-transfused patients (median 228 micrograms/l, range 58-3160 v 43, 22-310). Liver siderosis and fibrosis were found in 8/9, and cirrhosis in two who died at age 39 and 42 of complications of iron overload. SF was independent of age, sex, or severity of haemolysis. The prevalence of HLA-A3 antigen in PK deficient patients was not significantly different from that of our healthy population (29.6% v 23%). The HLA-A3 positive, non-transfused patients had significantly higher SF values than the HLA-A3 negative ones (median 675 micrograms/l, range 340-3160 v 145, 58-400). A pedigree study of six high SF-probands indicated that iron overload has a multifactorial pathogenesis. In particular, the association of PK deficiency-induced haemolysis, splenectomy and an additional factor (heterozygosity for idiopathic haemochromatosis, ineffective erythropoiesis) leads to severe iron accumulation. We suggest that monitoring iron status would be useful in PK deficient patients, particularly in splenectomized and HLA-A3 positive ones, to identify those at risk of iron overload and prevent the clinical consequences of iron accumulation.

Adolescent↗
PubMed1989

Relative iron deficiency in hereditary spherocytosis.

Seventy-three patients with hereditary spherocytosis (HS) (58 nonsplenectomized, 15 splenectomized) were studied to evaluate iron status and the adequacy of iron availability for erythropoiesis. Splenectomized patients, who had hemoglobin levels in the normal or upper normal range, had higher levels of serum iron, transferrin saturation, and serum ferritin than normal matched controls and normal zinc protoporphyrin (ZnPP) levels. On the contrary, nonsplenectomized patients presenting with mild to severe anemia had higher red cell ZnPP concentrations than both splenectomized subjects and matched normal controls. ZnPP in nonsplenectomized patients correlated inversely with Hb concentration, mean corpuscular volume (MCV), mean red cell hemoglobin concentration (MCHC), transferrin saturation, and serum iron, and directly with reticulocyte count. At multiple regression analysis only Hb concentration was a significant explanatory variable for high ZnPP. The authors conclude that a number of nonsplenectomized HS patients have relative iron deficiency primarily because of expansion of erythropoiesis caused by anemia.

Adolescent↗
PubMed1988

Erythrocyte pyruvate kinase deficiency: 11 new cases.

Eleven new cases of red cell pyruvate kinase (PK) deficiency with congenital haemolytic disease from 10 unrelated Italian families were characterized using the methods recommended by the International Committee for Standardization in Haematology (ICSH). All patients were double heterozygotes for the PK gene. The 10 variants were designated PK 'Lecce,' 'Parma,' 'Verona,' 'Milano,' 'Soresina,' 'Macerata,' 'Sassari,' 'Genova,' 'Mantova' and 'Brescia.' PK 'Sassari' was associated with glucose-6-phosphate dehydrogenase deficiency in two siblings. All mutants displayed multiple biochemical abnormalities except for PK 'Lecce' that only showed decreased red cell PK activity. No relation was found between the severity of anaemia and either the residual PK activity or specific biochemical enzyme abnormalities. Increased serum ferritin levels were detected in most of the patients, suggesting the need for systematically monitoring iron status in this disease.

Adolescent↗
PubMed1985

Triosephosphate isomerase deficiency: 2 new cases.

2 new cases of triosephosphate isomerase (TPI) deficiency associated with severe haemolytic anaemia in 2 unrelated Italian families are described. Only 1 case was extensively investigated. TPI deficiency was detectable in erythrocytes, leucocytes, platelets and plasma. The mutant enzyme showed normal Km for GAP and increased Km for DHAP, with an higher than normal equilibrium constant, decreased thermostability, and abnormal electrophoretic pattern due to the lack of the fastest moving component. The immunological characterization revealed a lower than normal inactivation by specific antiserum, while the double immunodiffusion pattern and the precipitin curve were normal. Lymphocyte, granulocyte and platelet functions were impaired.

Blood Platelets↗
PubMedDate not supplied

Congenital non-spherocytic haemolytic anaemias.

Congenital non-spherocytic haemolytic anaemias are a heterogeneous group of disorders caused by an ineffective normal-type enzyme or, more commonly, by a structurally abnormal and ineffective mutant enzyme. The first part of this paper deals with the laboratory diagnosis of these diseases, which is based on a three-step approach: demonstration of the haemolytic nature of the disease, demonstration that the cause of haemolysis is intracorpuscular and demonstration of the presence of an absolute or relative enzyme deficiency. Moreover, the possible causes of false negative results in standard enzyme assays are briefly commented. The second part focuses on the main clinical, laboratory and biochemical features of the most common enzyme deficiencies of both the Embden-Meyerhof pathway and purine and pyrimidine metabolism, with particular mention of the cases identified in Italy.

5'-Nucleotidase↗