Medical education: capitalizing on the lecture method.
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Education, Medical↗
Biomedical subjects
F Vella
Publications and source records attributed to F Vella.
Variability in the interaction of beta-thalassemia with the alpha-chain variants Hb G-Philadelphia and Hb Rampa.
Two unrelated families are reported in which beta-thalassemia trait occurred with a heterozygosity of Hb G-Philadelphia (alpha2 68(E17)Asn leads to Lys beta2) in one family and with Hb Rampa (alpha2 95(G2)Pro leads to Ser beta2) in the other. The percentage of Hb G-Philadelphia was not influenced by the simultaneous presence of a beta-thalassemai determinant, but that of Hb Rampa was descreased from 20% in the simple heterozygote to about 6% in persons with the Hb Rampa-beta-thalassemia combination. Data from in vitro recombination experiments with isolated alpha X, alpha A, and beta A chains, with heme attached, indicated a preferential formation of Hb A over Hb Rampa but not over Hb G-Philadelphia in conditions of relative beta-chain deficiency. This suggests that the rate of assembly of monomers to form dimers or tetramers can be an important mechanism of controlling the quantity of certain hemoglobin variants with critical substitutions in heterozygotes.
Adolescent↗
Variation in hemoglobin A2.
The structure, properties and function of, and some biosynthetic and genetic aspects of, Hb A2 are described. The structural variants of Hb A2 are reviewed and their geographical distribution presented. Hb A2, Hb A2-Flatbush and Hb A2-Babinga are characteristic of negro populations and may have originated in Western or Central Africa. Hb A2-Sphakia is characteristic of Canadian Amerindian and Hb A2-Indonesia of Indonesian/Malay populations. Hb A2-NYU has only been found sporadically and most frequently in persons of Eastern European origin. The other three variants of Hb A2 have only been reported in a single person or in single families. Some conditions which are associated with changes in Hb A2 levels are reviewed.
Africa, Central↗
Some physicochemical properties of hemoglobin-manitoba (alpha2 102Ser replaced by Arg (G9) beta2).
Hb-Manitoba was discovered in 1970 [1] in a Canadian family of British origin. Recently we observed the same variant in a second family, and found that the oxy-derivative of Hb-Manitoba is slightly unstable at 65 degrees C, dissociates less readily at alkaline pH than does Hb-A, and forms asymmetric hybrids with other hemoglobins which are readily detectable by electrophoresis.
Adult↗
Haemoglobin G Norfolk: alpha 85 (F6) Asp leads to Asn.
The characterisation of haemoglobin G Norfolk (alpha2 85 Asp leads to Asn 2) is described. This variant has been identified in the heterozygous state in three apparently unrelated English families of which two are resident in England and the other in Canada.
Amino Acids↗
The human hemoglobin variants in Canada.
This report summarizes the results of a search for abnormal hemoglobin variants by use of a filter paper electrophoresis technique on 228,300 blood samples obtained from various parts of four Canadian provinces. Abnormal variants were found in 438 samples and were of 27 different varieties, including six new ones. In addition, the characteristics of beta-thalassemia were found in 147 samples. The types of variant found, and their geographical and ethnic origin are presented.
Alberta↗
Mechanical stability of human haemoglobins.
The mechanical stability of oxyhaemoglobins A, Agenogi, C, E, F, J Toronto, Little Rock, Riverdale-Bronx, San Diego, Stanleyville-2, and Tak was found to be similar, that of A2, Duarte and D Punjab was slightly subnormal, and of Bucuresti, H, Köln, M Saskatoon, S, Shepherds Bush and Zürich was markedly decreased. Cyanide increased the stability of the latter haemoglobins.
Cyanides↗