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Biomedical subjects

R M Baine

Publications and source records attributed to R M Baine.

10 recordsLinked to original sources
PubMed1989

Hb Catonsville (glutamic acid inserted between Pro-37(C2)alpha and Thr-38(C3)alpha). Nonallelic gene conversion in the globin system?

Hb Catonsville is an unstable variant in which glutamic acid is inserted into the alpha-globin chain between Pro-37(C2) and Thr-38(C3). The peptide sequence data are consistent with the DNA sequence of the polymerase chain reaction-amplified fragment of the variant globin gene, which shows the insertion of the triplet codon--GAA--into the mutant alpha-globin gene. In the normal alpha-globin gene cluster the codon for glutamic acid is GAG rather than GAA. Thus, there are two features unique to Hb Catonsville, one the insertion of a single residue into the interior of the alpha-globin chain, and two the presence of the alternate codon for glutamic acid. The experimental evidence suggests that Hb Catonsville may be an example of nonhomologous nonallelic gene conversion, an observation not previously reported in this gene family. The mutation occurs in the critical alpha 1 beta 2 interface of the hemoglobin tetramer and leads to a variant with high oxygen affinity, a reduced cooperativity, and Bohr effect.

Alleles↗
PubMed1983

Hemolytic disease of the newborn caused by a new deletion of the entire beta-globin cluster.

We describe a new type of gamma delta beta-thalassemia in four generations of a family of Scotch-Irish descent. The proposita presented with hemolytic disease of the newborn, which was characterized by a microcytic anemia. Initial restriction endonuclease analysis of the DNA showed no grossly abnormal patterns, but studies of polymorphic restriction sites and gene dosage revealed an extensive deletion that removed all the beta- and beta-like globin genes from the affected chromosome. In situ hybridization of chromosome preparations with radioactive beta-globin gene probes showed that only one 11p homolog contained the beta-globin gene cluster in the affected family members.

Adult↗
PubMed1983

Alpha-thalassemia in Ashkenazi Jews.

Members of a Jewish family of Polish origin were found to have hypochromic, microcytic erythrocytes. By restriction endonuclease analysis of DNA, the propositus, a brother, and an aunt were found to have a single alpha-globin gene on each chromosome 16. Five family members have one chromosome bearing two alpha-genes (5' and 3') with a single alpha-gene on the homologous chromosome. Gene mapping indicated that the chromosome bearing a single alpha-gene arose via an unequal crossover between misaligned 5' and 3' alpha-genes and was introduced into the family from three separate sources. In addition, a Jewish man of Hungarian origin was found to have alpha-thalassemia trait with single alpha-genes on both chromosomes 16 and a survey of 25 Jewish subjects yielded one man of German origin with an alpha-gene deletion. Alpha-thalassemia should be considered in the differential diagnosis of disease in Jewish persons with microcytic, hypochromic erythrocytes.

Adult↗
PubMed1978

Microchromatographic methods for hemoglobin A2 quantitation compared.

On 20 consecutive work days during four weeks, one technologist performed 24 microchromatographic determinations of hemoglobin A2 (Hb A2) by each of four methods: the Efremov procedure requiring Tris/HCl buffer, the original Huisman technique with use of glycine developer, and two commercial test kits in which a modified glycine developer is used. The bloood samples tested were obtained from 12 adults with no hematological abnormality and from 12 beta-thalassemia carriers previously diagnosed by familial and hematologic studies. Results by the first method and the two commercial kits (one from Helena Laboratories and one from Isolab, Inc.) did not differ significantly in precision for either the normal or beta-thalassemia trait samples. For both sample types, the second method yielded larger coefficients of variation than those obtained with the other methods. Moreover, the second method was the only one with which values overlapped for normal samples and samples with above-normal Hb A2 concentrations.

Chromatography, Ion Exchange↗
PubMed1976

Trimodality in the proportion of hemoglobin G Philadelphia in heterozygotes: evidence for heterogeneity in the number of human alpha chain loci.

The extent of variability in the number of human hemoglobin (Hb) alpha chain loci has not yet been conclusively determined. There is evidence that in some populations individuals may possess two alpha-chain loci, while in other populations only one locus is present. Electrophoresis of peripheral blood from 53 heterozygotes for Hb G Philadelphia (alpha 68 Asn leads to Lys) revealed that the proportion of Hb G is trimodally distributed, with modes at approximately 20, 30, and 40% Hb G. Familial, hematologic, and statistical studies suggest that hte proportion of Hb G is not random but is genetically controlled and inversely correlated with mean cell volume. Two alternative genetic models are proposed to explain these findings: one assums alpha-thalassemia, while the other postulates variability in the number of alpha-chain loci in the American Black population. Biosynthetic studies of blood from 15 subjects revealed balanced synthesis of alpha and beta globin chains in heterozygotes from all three classes, strongly supporting variable gene dosage rather than alpha-thalassemia as the mechanism underlying the observed trimodality in the proportion of Hb G. Incompatibilities between out results and current concepts of alpha-thalassemia are discussed in the context of differences between Black compared with Oriental and Italian forms of Hb H disease.

Alleles↗