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Biomedical subjects

M A Frohman

Publications and source records attributed to M A Frohman.

60 records · Page 4Linked to original sources
PubMed1987

Differential expression of the mouse homeobox-containing gene Hox-1.4 during male germ cell differentiation and embryonic development.

Hox-1.4 is a mouse homeobox-containing gene (initially identified as HBT-1), whose expression appears to be testis-specific in the adult animal. Examination of Hox-1.4 transcripts in RNA from testes of mutant mice deficient in germ cells confirms that Hox-1.4 expression within the testis is germ cell-specific. Enriched populations of spermatogenic cells were used to localize the expression of Hox-1.4 specifically to germ cells that have entered into and progressed beyond the meiotic prophase stage of differentiation and to demonstrate the presence of two different size Hox-1.4 transcripts. Examination of RNA from teratocarcinoma cell cultures and mouse embryos at 10.5-16.5 days of gestation demonstrated the presence of several Hox-1.4 transcripts, which are larger than those present in germ cells. In the midgestation fetus, Hox-1.4 expression is most abundant in the spinal cord.

Alleles↗
PubMed1980

Human adenosine deaminase and its binding protein in normal and adenosine deaminase-deficient fibroblast cell strains.

Reduced or absent adenosine deaminase activity occurs in all tissues of some patients with severe combined immunodeficiency disease. In this report we describe (a) a sensitive and specific radioimmunoassay for fibroblast adenosine deaminase and its binding protein, (b) the importance of various tissue culture media on the expression of fibroblast adenosine deaminase, and (c) the levels of immunoreactive adenosine deaminase compared to its binding protein in normal and homozygous adenosine deaminase-deficient fibroblast cell strains.

Adenosine Deaminase↗
PubMed1979

Radioimmunochemical quantitation of human adenosine deaminase.

Markedly reduced or absent adenosine deaminase activity in man is associated with an autosomal recesive form of severe conbined immunodeficiency disease. To further define the genetic nature of this enzyme defect, we have quantitated immunologically active adenosine deaminase (CRM) in the hemolysate of homozygous deficient patients and their heterozygous parents. A highly specific radioimmunoassay was developed capable of detecting 0.05% of normal erythrocyte adenosine deaminase. Hemolysates from nine heterozygotes (five families) showed a wide range in CRM (32--100% of normal) and variable absolute specific activities with several being at least 1 SD BELOW THE NORMAL MEAN. Hemolysates from four unrelated patients showed less than 0.09% adenosine deaminase activity with CRM ranging from less than 0.06 to 5.6% of the normal mean. In conclusion, heterozygote and homozygote hemolysates from five of the eight families analyzed revealed variable levels of CRM suggesting heterogeneous genetic alteration or expression of the silent or defective allele(s) of adenosine deaminase.

Adenosine Deaminase↗
PubMed1979

Use of protein A--containing Staphylococcus aureus as an immunoadsorbent in radioimmunoassays to separate antibody-bound from free antigen.

Heat killed, formalinized Cowan I strain Staphylococcus aureus (PASA) was examined for its utility as a solid-phase immunoadsorbent in various RIA procedures. Specific antibody could be adsorbed to PASA and then reacted with radiolabeled and unlabeled hormone, or alternatively, PASA could be added to antibody-hormone mixture in order to separate antibody-bound from free antigen. Both methods compared favorably with the more standard double-antibody method in each system tested. Antibodies produced by rabbits, guinea pigs, monkeys, and humans were precipitated equally by PASA and double antibody, whereas antibody raised in sheep was precipitated much less by PASA than by double antibody. Antibody bound to PASA was found to reach equilibrium of binding more slowly than unbound antibody for both rapid (TRH) and slow (rPRL) reactions. Binding of either free of complexed IgG by PASA, however, was extremely rapid, reaching equilibrium in less than 30 sec. This rapid binding was utilized in kinetic experiments which would not have been possible with slower-reacting precipitating agents. The versatility permitted by this propertly constitutes one of the most useful characteristics of PASA. Other important attributes of PASA include its convenience, economy, and wide applicability.

Antibodies↗