Search PubMed⌕ Search

Biomedical subjects

M D Cooper

Publications and source records attributed to M D Cooper.

At least 73 records · Page 4Linked to original sources
PubMed1997

An amphibian CD3 homologue of the mammalian CD3 gamma and delta genes.

T cell receptor (TCR) genes have been identified in representatives of both cartilaginous and bony vertebrates. The CD3 chains that serve as signal transducing elements of the TCR complex in mammals have been defined to a limited extent in birds. In these studies a CD3 homologue was identified in an amphibian representative, Xenopus laevis, using degenerate oligomer primers designed from conserved regions of avian and mammalian CD3 gamma/delta subunits. The reverse transcriptase polymerase chain reaction amplified product of Xenopus splenocyte RNA was then used to isolate full-length cDNA clones from a splenic library. When employed as probes, the cDNA clones hybridized with a 1-kb mRNA transcript in Xenopus T cells, but not in other cell types. Comparison of the deduced amino acid sequence indicated a similar degree of homology with mammalian and avian CD3 gamma and delta chains. Genomic analysis indicated that the Xenopus CD3 molecule is encoded by five exons, a structure resembling the mammalian CD3 delta gene rather than the seven exon CD3 gamma gene. Southern blot analysis and sequencing of the 5' flanking region failed to yield evidence of a related Xenopus gene. This amphibian CD3 gene thus appears to represent an ancestral form of the mammalian CD3 gamma and delta genes.

Amino Acid Sequence↗
PubMed1997

Measurement of immunoglobulin synthesis using the ELISPOT assay.

We describe a method for the detection of specific antibody-producing cells from either in vitro or in vivo immunization. These techniques are especially useful for detecting antibodies from developing hybridomas. We have successfully used the system to detect isotype-specific antibodies to a variety of bacterial antigens which were produced by heterohybridomas.

Antibodies, Monoclonal↗
PubMed1997

B cell development and differentiation.

The initial phases of B cell development depend on interactions between the cell surface molecules and secreted products of stromal cells with their receptor-ligand partners on lymphoid progenitors. Recent research in this area has greatly advanced our understanding of B cell development and differentiation. Antigen receptors on pre-B and B cells play key roles in the progression of this differentiation process, as revealed by targeted and inherited gene mutations that disrupt B cell development and by the transgenic repair of these mutations in mice.

Animals↗
PubMed1997

Age-related changes in serum immunoglobulins in patients with familial IgA deficiency and common variable immunodeficiency (CVID).

The concentration of serum immunoglobulins in individuals with IgA deficiency (IgAD) and CVID can vary with age to have practical implications for evaluation, therapy, and genetic analysis. Most IgAD and CVID patients in our clinic population in the Southeastern United States have inherited part or all of two extended MHC haplotypes, referred to as haplotype 1 (HLA-DQB1 0201, HLA-DR3, C4B-Sf, C4A-0, G1-15, Bf-0.4, C2-a, HSP-7.5, TNF alpha-5, HLA-B8, HLA-A1) and haplotype 2 (HLA-DQB1 0201, HLA-DR-7, C4B-S, C4A-L, G11-4.5, Bf-0.6, C2-b, HSP-9, TNF alpha-9, HLA-B44, HLA-A29). In the present study, the clinic records of 68 CVID patients and 73 IgAD patients were reviewed to determine whether patients with familial or MHC-associated IgAD or CVID experience changes in serum immunoglobulin concentrations. An increase in serum immunoglobulin to the normal range was associated with clinical improvement in one patient with CVID and haplotype 2, two patients with IgAD and haplotype 2, and one IgAD patient whose haplotype was not determined. Two patients with haplotype 1 and one with haplotype 2 had a significant decline in serum immunoglobulin: one progressed from normal to IgAD associated with IgG subclass deficiencies, and two progressed from IgAD to CVID. Five of the seven patients with notable changing serum immunoglobulin levels have a family member with either IgAD or CVID. The findings suggest that familial, MHC-associated IgAD and CVID may be either progressive or reversible disorders, and emphasize the value of monitoring immunoglobulin levels in affected individuals and their family members.

Adolescent↗
PubMed1997

Interferons alpha/beta inhibit IL-7-induced proliferation of CD4- CD8- CD3- CD44+ CD25+ thymocytes, but do not inhibit that of CD4- CD8- CD3- CD44- CD25- thymocytes.

Type 1 interferons (IFN-alpha/beta) have recently been shown to inhibit interleukin-7 (IL-7)-induced growth and survival of early B-lineage cells. The CD3- CD4- CD8- (triple negative; TN) thymocytes from normal mice strongly proliferated upon stimulation with IL-7 in suspension, culture. Such an IL-7-induced proliferation was suppressed by the addition of IFN-alpha/beta, but a fraction of the TN thymocytes still showed proliferation. The IL-7-induced growth of TN thymocytes from acid mice, which lack the CD44- CD25- subpopulation, was completely inhibited by the addition of IFN-alpha/beta. The IL-7 induced proliferation of CD4- CD8- thymocytes from T-cell receptor (TCR) transgenic mice, the majority of which are CD3+ CD44- CD25-, was resistant to IFN-alpha/beta-mediated suppression. In fetal thymus organ cultures (FTOC), the addition of IL-7 greatly increased the population of CD4- CD8- CD44+ CD25+ thymocytes and IFN-alpha/beta inhibited this IL-7-driven expansion. In contrast, the addition of IL-7 markedly decreased the percentages of CD4- CD8- CD3- CD44- CD25- cells, and IFN-alpha/beta reversed the effect and increased the subpopulations of CD44- CD25+ and CD44- CD25-. Finally, IFN-beta mRNA was found to be expressed in the thymus. The data suggest that type I interferons inhibit IL-7-driven proliferation of TN thymocytes, but do not block the normal differentiation process.

Animals↗
PubMed1997

Evaluation of penicillin and hyperbaric oxygen in the treatment of streptococcal myositis.

The purpose of this study was to evaluate effects of hyperbaric oxygen (HBO) and penicillin (PCN) therapy in a murine model of streptococcal myositis. The thighs of Swiss Webster mice were inoculated with Streptococcus pyogenes. Four groups were evaluated: (1) control (N = 10), (2) HBO treatment (N = 10), (3) PCN treatment (N = 8), and (4) PCN and HBO treatment (N = 6). Mortality (day of death) and the number of colony-forming units (cfu) were measured. PCN significantly lowered cfu from control (p < 0.05). Cfu in group 4 was significantly lower than PCN alone (p = 0.006). Survival was significantly longer in the PCN group compared with the control (p < 0.01). Survival in the combined treatment group was significantly longer than PCN alone (p < 0.01). These results suggest that (1) HBO treatment alone does not decrease mortality or bacterial proliferation in vivo significantly, (2) PCN therapy alone improves outcome significantly, and (3) the combined treatment of PCN and HBO exerts at least additive effects in both decreasing bacterial counts in vivo and increasing survival in this model.

Animals↗
PubMed1997

Unusual patterns of exon skipping in Bruton tyrosine kinase are associated with mutations involving the intron 17 3' splice site.

Seven individuals with the diagnosis of X-linked agammaglobulinemia were analyzed for mutations in Bruton tyrosine kinase (Btk) gene at both the cDNA transcript and genomic DNA levels. In addition, maternal carrier status was determined in six of the seven families by examining X chromosome-inactivation patterns for B cells in comparison with other types of blood cells. Three categories of mutations were identified: (1) three patients have missense mutations in either the pleckstrin or SH2 domains of Btk; (2) three patients exhibit mutations at or near intron/exon splice sites, two of which represent inherited mutations within the kinase domain; and (3) one patient has inherited a 2.5-kb deletion with the loss of a DNA segment encoding three exons of the kinase domain. Variation in the lengths of Btk transcripts was evident in two patients with splice-site mutations and in the patient with the DNA deletion. Sequences of the different cDNA transcripts from the patients with 3' splice-site mutations reveal complex patterns of exon skipping involving from one to four exons of the kinase domain. These findings implicate 3' splice sites of the penultimate exon in the recognition or processing of upstream exons.

Adolescent↗
PubMed1997

IgA deficiency.

Explore the source record for details and available documents.

Animals↗
PubMed1997

Utilization of advanced hygienist skills in the private practice.

PURPOSE: The purpose of this study was to survey dental hygiene graduates to determine utilization in the private practice setting of expanded functions taught in school. METHOD: A questionnaire was sent to 90 dental hygiene graduates from the classes of 1990-1994, of Indiana University-Purdue University, Fort Wayne. Analysis was done on utilization of specific expanded functions taught in school. Frequency tabulations of procedures performed and adequacy of preparation were done using the SAS software. The results were graphically represented in tables. RESULTS: Equal response from each class resulted in the total response rate of 74%. The expanded functions most frequently performed by dental hygienists were placing sealants followed by making cast impressions. Placing temporary and amalgam restorations were rarely performed. The majority of graduates felt adequately trained to perform these skills. CONCLUSION: Skills being required and taught in school are not being delegated in private practice. This survey shows the need for curriculum revisions and discrepancies between educational requirements and utilization.

Dental Hygienists↗
PubMed1996

Characterization of avian T-cell receptor gamma genes.

In birds and mammals T cells develop along two discrete pathways characterized by expression of either the alpha beta or the gamma delta T-cell antigen receptors (TCRs). To gain further insight into the evolutionary significance of the gamma delta T-cell lineage, the present studies sought to define the chicken TCR gamma locus. A splenic cDNA library was screened with two polymerase chain reaction products obtained from genomic DNA using primers for highly conserved regions of TCR and immunoglobulin genes. This strategy yielded cDNA clones with characteristics of mammalian TCR gamma chains, including canonical residues considered important for proper folding and stability. Northern blot analysis with the TCR gamma cDNA probe revealed 1.9-kb transcripts in the thymus, spleen, and a gamma delta T-cell line, but not in B or alpha beta T-cell lines. Three multimember V gamma subfamilies, three J gamma gene segments, and a single constant region C gamma gene were identified in the avian TCR gamma locus. Members of each of the three V gamma subfamilies were found to undergo rearrangement in parallel during the first wave of thymocyte development. TCR gamma repertoire diversification was initiated on embryonic day 10 by an apparently random pattern of V-J gamma recombination, nuclease activity, and P-and N-nucleotide additions to generate a diverse repertoire of avian TCR gamma genes early in ontogeny.

Amino Acid Sequence↗
PubMed1996

The mouse BP-1 gene: structure, chromosomal localization, and regulation of expression by type I interferons and interleukin-7.

The BP-1/6C3 antigen is a homodimeric, phosphorylated type II membrane integral glycoprotein expressed on immature B-lineage cells, bone marrow stromal cells, thymic cortical epithelial cells, endothelial cells, enterocytes, and renal proximal tubular cells. Biochemical and molecular analysis identified BP-1 as glutamyl aminopeptidase, an ectoenzyme that catalyzes the hydrolysis of acidic amino acid residues from the amino termini of regulatory peptides. We have isolated genomic clones that encode the BP-1 gene (gene symbol Enpep). The gene spans more than 110 kb and contains 20 exons. Except for the first and the last exons, it is composed of small exons ranging from 56 to 171 bp that are separated by introns ranging from less than 100 bp to approximately 10 kb. The zinc binding motif HEXXH and the glutamic acid residue 19 amino acids downstream, which also binds zinc, are encoded in exons 5 and 6. Primer extension analysis revealed a common major transcriptional start site in a pre-B cell line, in a bone marrow stromal cell line, and in kidney cells. The promoter region contains a TATA-like element and potential DNA-binding motifs for lymphocyte-specific transcription factors including Ikaros, BSAP, PU.1, and octamer binding proteins, as well as DNA binding motifs for several ubiquitous transcription factors. An interferon responsive element also located in the promoter region appeared to be functional, since type I interferons (IFN-alpha/IFN-beta) upregulated BP-1 expression in pre-B cell lines. A 2.1-kb promoter fragment, when fused to a luciferase reporter gene, was able to drive luciferase expression in pre-B cells, which normally express BP-1, and the Ag8 cells, in which BP-1 expression is extinguished. The BP-1/ Enpep gene was localized to a distal region of mouse chromosome 3 in a region homologous to human chromosome 4q25. Interestingly, while interleukin-7 (IL-7) induced both cell growth and increased BP-1 expression, IFN-alpha/IFN-beta upregulated BP-1 expression but inhibited IL-7 induced proliferation. This finding indicates that the upregulated BP-1 expression can be disassociated from the cell growth signal.

Amino Acid Sequence↗
PubMed1996

gamma/delta T cell-deficient mice have impaired mucosal immunoglobulin A responses.

Mucosal tissues of mice are enriched in T cells that express the gamma/delta T cell receptor. Since the function of these cells remains unclear, we have compared mucosal immune responses in gamma/delta T cell receptor-deficient (TCRdelta-/-) mice versus control mice of the same genetic background. The frequency of intestinal immunoglobulin (Ig) A plasma cells as well as IgA levels in serum, bile, saliva, and fecal samples were markedly reduced in TCRdelta-/- mice. The TCRdelta-/- mice produced much lower levels of IgA antibodies when immunized orally with a vaccine of tetanus toxoid plus cholera toxin as adjuvant. Conversely, the antigen-specific IgM and IgG antibody responses were comparable to orally immunized control mice. Direct assessment of the cells forming antibodies against the tetanus toxoid and cholera toxin antigens indicated that significantly lower numbers of IgA antibody-producing cells were present in the intestinal lamina propria and Peyer's patches of TCRdelta-/- mice compared with the orally immunized control mice. The selective reduction of IgA responses to ingested antigens in the absence of gamma/delta T cells suggests a specialized role for gamma/delta cells in mucosal immunity.

Animals↗
PubMed1996

Fate of surrogate light chains in B lineage cells.

Biosynthesis of the immunoglobulin (Ig) receptor components and their assembly were examined in cell lines representative of early stages in human B lineage development. In pro-B cells, the nascent surrogate light chain proteins form a complex that transiently associates in the endoplasmic reticulum with a spectrum of unidentified proteins (40, 60, and 98 kD) and Bip, a heat shock protein family member. Lacking companion heavy chains, the surrogate light chains in pro-B cells do not associate with either the Ig(alpha) or Ig(beta) signal transduction units, undergo rapid degradation, and fail to reach the pro-B cell surface. In pre-B cells, by contrast, a significant portion of the surrogate light chain proteins associate with mu heavy chains, Ig(alpha), and Ig(beta) to form a stable receptor complex with a relatively long half-life. Early in this assembly process, Bip/GRP78, calnexin, GRP94, and a protein of approximately 17 kD differentially bind to the nascent mu heavy chains. The 17-kD intermediate is gradually replaced by the surrogate light chain protein complex, and the Ig(alpha) and Ig(beta) chains bind progressively to the mu heavy chains during the complex and relatively inefficient process of pre-B receptor assembly. The results suggest that, in humans, heavy chain association is essential for surrogate light chain survival and transport to the cell surface as an integral receptor component.

Antigens, CD↗
PubMed1996

Clonal stability of blood cell lineages indicated by X-chromosomal transcriptional polymorphism.

The idea that stem cells oscillate between a state of activity and dormancy, thereby giving rise to differentiating progeny either randomly or in orderly clonal succession, has important implications for understanding normal hematopoiesis and blood cell dyscrasias. The degree of clonal stability in individuals also has practical implications for the evaluation of clonal lymphomyeloproliferative diseases. To evaluate the clonality pattern of the different types of blood cells as a function of time we have validated the applicability, sensitivity, and reproducibility of a thermostable ligase reaction to detect transcripts of the G6PD allele on the active X-chromosome in normal heterozygous females. While the ratio of the two X-chromosome-derived allelic transcripts varied widely among hemopoietic tissues in a given individual, this allelic ratio was virtually identical in all types of mature myeloid and lymphoid cells. Longitudinal studies indicated constancy of the G6PD allelic ratio in blood cells over a 912-d period of observation in healthy females. The individual variability observed in this allelic ratio suggests that the progeny of a relatively small number of original embryonic hemopoietic stem cells, approximately eight, contribute to the sustained production of all types of blood cells in healthy individuals.

Alleles↗
PubMed1996

B cells are generated throughout life in humans.

This analysis of B cell development as a function of age reveals a relatively widespread distribution of progenitor B (pro-B), pre-B, and B cells in fetal tissues, and thus supports the idea of a multifocal origin of B lineage cells during embryonic development. From mid-gestation onward, the bone marrow is the major site of B cell generation in humans. A relatively constant ratio of bone marrow precursors to B cells of immature phenotype (CD24highCD10+CD20lowIgD-) is maintained from mid-gestation through the eighth decade of life. The persistence of recombinase gene activity in pro-B cells further attests the sustained production of B cells in bone marrow. Interestingly, a subpopulation of B cells with mature phenotype (CD24lowCD10-CD20highIgD+) accumulates in the bone marrow during childhood, and this becomes the predominant B cell subpopulation in adult bone marrow. This mature population of bone marrow B cells may represent a subpopulation of recirculating B cells that have undergone selection in the periphery.

Adult↗
PubMed1996

Expression and function of Fas antigen on activated murine B cells.

We have studied the expression and function of Fas antigen on murine B lymphocytes. While Fas was present on only a few B cells in the bone marrow, spleen, lymph node or peripheral blood, its expression could be strongly up-regulated by stimulation with soluble CD40 ligand (CD40L). Treatment with anti-IgM and interleukin-4 (IL-4) alone did not induce significant Fas expression but enhanced CD40L-mediated up-regulation of Fas expression. The T cell-derived signal via CD40 is therefore a potent inducer of Fas expression by B lymphocytes. The sensitivity to Fas-mediated apoptosis was found to depend on the duration of B cell activation. B cells activated for 1 day were resistant to Fas-mediated cell death, whereas B cells activated for 3 days were relatively sensitive. Interestingly, different sensitivity to Fas-mediated death signal was observed in 2-day activated B cells. It was found that B cells stimulated with CD40 L alone were more sensitive to Fas-mediated apoptosis than were cells stimulated with CD40L plus anti-IgM or IL-4, and in particular, the combination of the two. The greater sensitivity exhibited by B cells stimulated with CD40L alone seems to be related to limited activation of these cells in the absence of additional stimulation. Co-stimulation of B cells in the presence of CD40L and anti-Fas antibody resulted initially in activation of B lymphocytes, as reflected by the expression of activation markers and cell growth, but this was followed by growth inhibition and cell death. The data demonstrate that the B cell response can be regulated positively and negatively by signaling through CD40 and Fas antigens, respectively.

Animals↗
PubMed1996

Gamma delta T cells are secondary participants in acute graft-versus-host reactions initiated by CD4+ alpha beta T cells.

To examine the role of T cell subpopulations in an acute graft-versus-host (GVH) reaction, gamma delta T cells and alpha beta T cells expressing one of the two prototypic V beta families were negatively isolated from adult blood samples and injected into allogeneic chick embryos. CD4+ alpha beta T cells expressing either V beta 1 or V beta 2 receptors were equally capable of inducing acute GVH reactions, consistent with the idea that alpha beta T cell alloreactivity is determined by CDR3 variability. By themselves, the gamma delta T cells were incapable of inducing GVH reactions. However, host gamma delta T cells were recruited into the donor alpha beta T cell-initiated lesions, where they were activated and induced to proliferate. The data suggest that gamma delta T cells may play a secondary role in GVH reactions.

Acute Disease↗