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Biomedical subjects

D Brown

Publications and source records attributed to D Brown.

At least 559 records · Page 31Linked to original sources
PubMed1993

Cytoplasmic tails of human complement receptor type 3 (CR3, CD11b/CD18) regulate ligand avidity and the internalization of occupied receptors.

To evaluate the role of the cytoplasmic tails of CD11b and CD18 in ligand binding and internalization of the human complement receptor type 3 (CR3, CD11b/CD18), wild type, and truncation mutants of CD11b and CD18 cDNA were expressed in COS fibroblastoid cells and assayed for surface membrane expression, ligand binding, and internalization. Truncated CD11b (alpha 1119T) and CD18 (beta 728T) subunits retaining, respectively, two and five residues of the putative cytoplasmic tails were generated by in vitro mutagenesis. Binding of alpha 1119T beta and alpha beta 728T heterodimeric receptors to iC3b was increased by 330% and 210%, respectively, relative to wild type CR3, suggesting that both cytoplasmic tails of CR3 negatively control receptor avidity. Internalization of antibody cross-linked wild type CR3 occurred predominantly through coated pits. Truncation of the cytoplasmic tail of CD18 but not of CD11b markedly reduced coated pit internalization of CR3, an effect also produced by a single F754A mutation involving one of two putative NPXF internalization signals in CD18.

Amino Acid Sequence↗
PubMed1993

Identification of pig chromosomes in pig-mouse somatic cell hybrid bivariate flow karyotypes.

To identify pig chromosomes in pig-mouse somatic cell hybrids, dual-laser flow karyotypes and GTG-banded metaphase spreads of pig, mouse, and 7 pig-mouse hybrid cell lines were compared. Pig chromosomes no. 1, 2, 5, 6, 10, 11, 13, 14, 16, 18, X and Y were tentatively assigned to individual peaks in the pig flow karyotype on the basis of DNA content vs. relative chromosome length. In the 7 hybrid cell lines, 7 out of 8 peaks distinct from those of the mouse cell line could be correlated with the presence of pig chromosomes no. 5, 9, 10, 11 or 16, 14, 15, and 18, whereas 1 peak appeared to correspond to the presence of 1 middle-size chromosome (3, 4, or 7). Other pig chromosomes present in the hybrids could not be detected with certainty due to superposition with mouse peaks and mouse chromosome rearrangements.

Animals↗
PubMed1993

The effect of adrenalectomy on the restraint stressed induced suppression of MHC class II expression by murine peritoneal macrophages.

Restraint stress suppresses the expression of MHC class II (I-A) glycoproteins by murine peritoneal macrophages. In order to evaluate the role of the pituitary adrenal axis, the effect of restraint stress on I-A expression by macrophages from adrenalectomized mice was evaluated. Adrenalectomy resulted in elevated levels of ACTH but abrogated the increase in corticosterone that results from restraint stress. The expression of I-A by macrophages from adrenalectomized mice was similar to that of sham operated mice or untreated mice. Adrenalectomy ameliorated the suppressive effects of restraint but the expression of I-A was below that of macrophages from adrenalectomized control mice. These results suggest that other factors in addition to corticosterone may effect I-A expression by murine peritoneal macrophages. A survey of other neuropeptides and catecholamines indicated that the addition of ACTH or epinephrine to macrophage cultures resulted in a suppression of I-A expression.

Adrenalectomy↗