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Biomedical subjects

G Efremov

Publications and source records attributed to G Efremov.

15 recordsLinked to original sources
PubMed1981

Effectiveness of one tube osmotic fragility screening in detecting beta-thalassaemia trait.

The effectiveness of the one tube method of osmotic fragility with three buffered solutions (0.32% saline, 0.36% saline, and tyrode) as a screening test for beta-thalassaemia trait was evaluated in several groups of subjects from Greece, Yugoslavia, and Thailand. The results clearly demonstrated that 0.36% saline is the most sensitive and effective solution since it could detect 96 to 100% of heterozygotes with beta-thalassaemia, compared to about 80% with both 0.32% saline and tyrode. However, 0.36% saline gave false positive results in normal subjects and was also positive in haematological disorders which influence osmotic fragility. The screening test with 0.36% saline was applied more precisely in 1371 subjects. The test was false positive in 41 (9.1%) of 455 normal subjects while of 438 confirmed heterozygotes with beta-thalassaemia it was positive in 431 (98%) and negative in only seven (2%). The test was also found to be positive in 80% of patients with iron deficiency anaemia and alpha-thalassaemia trait, in 68% of patients with Hb E trait, in 40% of patients with Hb S trait, and in 78% of heterozygotes with rare haemoglobin variants. The increased sensitivity and effectiveness of 0.36% saline in detecting beta-thalassaemia trait and other disorders influencing osmotic fragility as compared to 0.32% saline and tyrode solutions was also confirmed in a study of 384 unselected schoolchildren.

Evaluation Studies as Topic↗
PubMed1981

[Alpha thalassemia in Macedonia].

The frequency of alpha thalassemia in SR Macedonia was determined with studies of Hb Bart's in 1.140 newborn babies. Hb Bart's was found in 83 infants. Distribution of the levels of Hb Bart's in these neonates, as determined by column chromatography on CM Sephadex, was trimodal. The mean values for Hb Bart's in the three groups were 0.5% (SD = 0.22), 1.61% (SD = 0.48), and 4.88% (SD = 0.81). The first group is believed to result from asynchronism of the neonatal "switch off" of gamma chains and activation of beta chain production. The second and the third group represent alpha thal2 and alpha thal1, respectively. Thus, the incidence of beta thal2 in SR Macedonia is 2.4%, and that of alpha thal1 0.8%. Hb H disease was found in three out of 16.000 school children. This form of alpha thalassemia was also found in five out of 2.800 patients examined for the course of anemia. Biosynthetic studies of family members of the eight individuals with Hb H disease showed that one parent is heterozygous alpha thal1 while the other is heterozygous alpha thal2. All individuals with alpha thalassemia had a reduced rate of synthesis of the alpha chains. The mean alpha/beta total activity ratio in individuals with Hb H disease was 0.51 (+/- 0.08), in heterozygous alpha thal1 0.74 (+/- 0.06), and in heterozygous alpha thal2 0.86 (+/- 0.06). Experiments with in vitro translation of globin mRNK isolated from patients with Hb H disease showed lower alpha/beta ratios (0.06) than the intact cell ratios. These results support previously published data that in Hb H disease and alpha thalassemia trait, there is quantitative deficit in alpha globin mRNK, which is a consequence of deleted alpha globin genes.

Adolescent↗
PubMed1965

Differences in cattle globins.

1. Comparisons have been made between electrophoretic mobilities of the cattle haemoglobins, HbA, HbB, HbC, HbD and HbF, at pH8.9. The fastest was HbB, then came in decreasing order HbF, HbC, HbA and HbD. 2. Globins were prepared from the main fractions of the five haemoglobins by CM-cellulose chromatography and investigated by starch-gel electrophoresis in four different buffer systems. In three of these (pH2.0 and 11.8) the globins appeared as two bands on stained starch gels. The slowest bands, the alpha-chains, showed the same rate of migration in all five globins. The faster bands, the non-alpha-chains, differed, that of HbF being the fastest and that from HbC the slowest. The other three were intermediate with, however, very small difference between the non-alpha-chains from HbA and HbD. 3. At pH1.8 in an acetate-phosphate-hydrochloric acid-urea buffer three bands appeared in all five globins of which the two slowest were indistinguishable in rates of migration, whereas the rates of migration of the third and fastest bands differed. Explanations for the occurrence of three bands are discussed.

Animals↗