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O David

Publications and source records attributed to O David.

58 records · Page 4Linked to original sources
PubMedDate not supplied

[The Hbf in Fanconi's anemia (author's transl)].

The Authors studied the HbF in an 8-year-old-girl with Fanconi's anemia. At the admission the patient was anemic (Hb 7,1 g%), thrombocytopenic and leucopenic, HbF was 23% (1,8 g%) with heterocellular distribution. Globin chain synthesis in the peripheral blood displayed an alpha/non alpha ratio of. 1,05. gamma-Chain analysis was performed: at position 136 the gamma G/gamma A ratio was 3:1 at positions 75 threonine was present in the 30% of the chains. The girl was transfused and oximetholone therapy was started. After 2 months of treatment, an increase of the Hb levels was observed. This improvement lasted about 5 months. The amount of HbF remained constant throughout the management. It may be suggested that androgens work only on HbA synthesis while the HbF-producing-cells are irresponsive to the hormonal stimulation.

Androgens↗
PubMedDate not supplied

Catalase against met-Hb excess during oximetries of dilute Hb-A samples.

Functional parameters of diluted Hb-A have been determined before and after addition of catalase and disodium-EDTA to the samples. There are no important differences between the results drawn from catalase added samples and catalase free ones, except for the fact the met-Hb level at pH 7.8 is significantly lower in the samples containing catalase. On the contrary, catalase is almost ineffective against met-Hb at pH 6.8, whereas its activity at pH 7.3 is rather modest. Another limitation is that catalase remains active against met-Hb for not more than 15-20 minutes after addition to the sample, which is just the time necessary for one complete (manual) oximetry.

Catalase↗
PubMedDate not supplied

Use of an enzymatic mixture against met-Hb excess during oximetry of dilute Hb-A solutions.

A mixture of NADH, cytochrome-C-reductase and methylene blue was employed to antagonize ferri(met)-Hb formation during oximetries of dilute samples of human Hb-A. Its efficacy is clear at any pH between 6.8, 7.3 and 7.8, in the presence of 100 mM NaCl. In these cases, ferri(met)-Hb decreases of about 2/3, compared with the enzyme-free controls, and p50 increases. On the contrary, when samples are examined at pH 7.3 with 600 mM NaCl and/or 100 mM NaCl plus 1 mM DPG, ferri(met)-Hb of the samples containing the enzymes also decreases, but not more than 1/2 of its initial value, whereas also p50 decreases. Finally, Bohr effect is lower in the samples containing the enzymes. In conclusion, the enzymatic mixture is very useful, but not easy to be handled; so, some observations for its correct use are required.

Adult↗