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Biomedical subjects

S H Boyer

Publications and source records attributed to S H Boyer.

At least 55 records · Page 3Linked to original sources
PubMed1976

Increased nerve-growth-factor beta-chain cross-reacting material in familial dysautonomia.

To determine whether dysautonomia arises from alteration in nerve-growth factor (NGF), we measured serum levels of NGF subunits in normal and dysautonomic subjects using a biologic assay based on neurite outgrowth from chick ganglions, a binding assay based on displacement of radiolabeled betaNGF from rabbit-ganglion microsomes, and radioimmunoassays of chi, gamma and betaNGF subunits via antiserum to mouse NGF polypeptides. A threefold increase (P less than 0.001) in serum antigen levels of the biologically active subunit (betaNGF) was found for dysautonomic as compared with normal subjects. By all other assays, the groups were alike. The marked discrepancy in betaNGF levels between antigenic and functional (biologic and binding) measurements suggests a qualitative abnormaltiy of betaNGF in dysautonomia. Alternatively, elevation of betaNGF antigen can be regarded as secondary to disease. This alternative seems less likely since we must then suppose that the normalcy of functional assays in spurious.

Adolescent↗
PubMed1976

Human Y-chromosome-specific reiterated DNA.

Radiolabeled reiterated DNA specific for the human Y chromosome has been obtained by extensive reassociations between [3H]DNA prepared from men and excess DNA from women. These highly purifed labeled sequences reassociate only with DNA from individuals with a Y chromosome. The percentage of Y-chromosome-specific DNA isolated from individuals with differing numbers of Y chromosomes is a function of the number of chromosomes present. The purifed Y-chromosome-specific sequences may represent between 7 and 11 percent of the human Y chromosome.

Base Sequence↗
PubMed1976

Enrichment of erythrocytes of fetal origin from adult-fetal blood mixtures via selective hemolysis of adult blood cells: an aid to antenatal diagnosis of hemoglobinopathies.

Red cell lysis in isotonic solutions containing NH4Cl, NH4HCO3, and a carbonic anhydrase enzyme inhibitor (acetazolamide) is a function of erythrocyte enzyme activity and permeability of cells to the inhibitor. Erythrocyte carbonic anhydrase activity is at least fivefold greater and acetazolamide permeability about tenfold less for adults than for newborns. In this setting, greater than 99.9% of red cells from adults can be hemolyzed at a time when greater than 25% of those from newborns remain intact. This easily applied method may be useful when antenatal diagnosis of hemoglobinopathies is otherwise precluded by contaimination with maternal erythrocytes. The feasibility of differential hemolysis via NH4Cl--HCO3-mediated, acetazolamide-modulated reactions is shown by the successful isolation of the few fetal-origin erythrocytes present in grossly nonbloody amniotic fluids and, in one instance, by approximately 3300-fold enrichment of apparently authentic fetal-origin red cells from the arm blood of a woman in her 18th wk of pregnancy.

Acetazolamide↗
PubMed1975

Fetal hemoglobin restriction to a few erythrocytes (F cells) in normal human adults.

During adult life, the quantity of fetal hemoglobin (HbF) present in F cells--that is, rare erythrocytes which are reactive with rabbit antiserum to human HbF during microscopic immunodiffusion--is sufficient to account for all of the small quantity (less than 0.7 percent) of HbF normally present in whole blood. Thus, erythrocytes are normally heterogeneous with respect to the presence of HbF.

Adult↗
PubMed1975

Variations in the frequency of fetal hemoglobin-bearing erythrocytes (F-cells) in well adults, pregnant women, and adult leukemics.

Fetal hemoglobin (HbF) in adult life is usually restricted to a few erythrocytes called F-cells. Their presence can be detected and the quantity of HbF per F-cell estimated by pericellular immunodiffusion reactions with anti-HbF. In normal adults F-cell frequency (range: 1 F-cell per 25 erythrocytes to 1 per 6800) and the mean amount of HbF per F-cell (range: approximately 14 to 28% of mean cell hemoglobin), although they are variables, remain constant over many months. Frequencies are similar in men and women. For a given individual, F-cell lifetimes are probably similar to those of other erythrocytes. F-cell production is not appreciably influenced by short term exposure to high altitude (approximately 4300 m) hypoxia. F-cell frequencies are briefly but substantially increased in many women during midpregnancy. In some women, presumptive 5- to 15-fold increases in F-cell production result in observed 3- to 7-fold increases in F-cell frequency during the 23rd to 31st weeks of gestation. These increases in F-cell frequency arise from selective alterations in maternal erythropoiesis and not from transplacental bleeding from the fetus. Substantial increases in F-cell frequency also occur in most adults with acute leukemia. In both pregnancy and leukemia, F-cell contributions of HbF are sufficient to account for modest elevations found in hemolysate HbF levels.

Adult↗
PubMed1972

Hemoglobin Malmö Beta-97 (FG-4) histidine--glutamine: a cause of polycythemia.

A striking history of familial polycythemia led to a search for an abnormal hemoglobin. None could be demonstrated by routine electrophoretic methods, but the propositus' hemolysate had increased oxygen affinity. Manipulation of the conditions of electrophoresis, and chromatographic methods, permitted identification of hemoglobin Malmö. Studies of hemolysates demonstrated a normal Bohr effect, decreased heme-heme interaction (n=1.58), and a p50 of 1.3 mm Hg at 10 degrees C and pH 7.2. The amino acid substitution occurs in the same position (FG-4) as that of hemoglobin Chesapeake, but in the beta-chain rather than the alpha-chain. The two types of hemolysate have different pathophysiologic properties, and carriers of hemoglobin Malmö exhibit more striking hematologic abnormalities.

Amino Acid Sequence↗
PubMed1971

Silent hemoglobin alpha genes in apes: potential source of thalassemia.

Small quantities of unusual hemoglobins were found in 1 of 37 chimpanzees and 2 of 6 gorillas. In each genus these hemoglobins contain unique alpha chains that differ from the ordinary by eight to nine scattered amino acid changes. The unusual chains arise from a hitherto undetected hemoglobin (3)alpha locus. No (3)alpha products are found in most apes; accordingly, (3)alpha is considered synthetically inactive in all but a few reversion mutants. Indirect evidence that the inactive (3)alpha locus is juxtaposed to an active alpha locus together with the supposition that (3)alpha exists in man provides a setting wherein thalassemia might be produced by nonhomologous recombination between two loci.

Amino Acid Sequence↗