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Biomedical subjects

M D Cooper

Publications and source records attributed to M D Cooper.

At least 469 records · Page 26Linked to original sources
PubMed1966

The IgA system. I. Studies of the transport and immunochemistry of IgA in the saliva.

1. Five patients with congenital or acquired agammaglobulinemia, lacking detectable IgA in serum or saliva, were transfused with 1 to 2 liters of normal plasma. In 2 of these patients IgA was demonstrated in parotid saliva collected after transfusion, but in none of the 5 was salivary IgG or IgM found. This observation indicates the selective transport of IgA into saliva. 2. The observation by others of an immunochemical difference between serum and sahvary IgA globulin was confirmed. In contrast to serum IgA, salivary IgA is attached to a protein having antigenicity which migrates as a gamma(1) globulin. We have termed this protein component "transport piece". 3. The transport piece has been found in an unbound form in the saliva of persons completely lacking IgA: agammaglobulinemic patients, ataxia-telangiectasia patients, a healthy person lacking IgA, and a newborn infant. Free transport piece still occurs in the normal child's saliva after IgA production begins. By adulthood there is usually no free transport piece in the saliva. 4. Heat-aggregated salivary IgA, like heat-aggregated serum IgA, does not fix complement. 5. Our findings offer support for the view that there is a distinct local antibody system for the protection of the mucous surfaces.

Agammaglobulinemia↗
PubMed1966

Restoration of gamma globulin production in agammaglobulinemic chickens.

Chickens irradiated and bursectomized in the newly hatched period consistently develop agammaglobulinemia and form no circulating antibodies; if the birds are treated immediately after operations by intra-abdominal injection of unirradiated autologous bursa cells, immunoglobulin production, lymphoid germinal centers, and plasma cells are restored; however, the birds fail to produce antibody to specific antigenic challenge.

Agammaglobulinemia↗
PubMed1966

The functions of the thymus system and the bursa system in the chicken.

The bursa of Fabricius and the thymus are "central lymphoid organs" in the chicken, essential to the ontogenetic development of adaptive immunity in that species. Surgical removal of one or both of these organs in the newly hatched chicken, followed by sublethal X-irradiation the next day, has permitted recognition of two morphologically distinct cell systems in the "peripheral lymphoid tissues" of the spleen, gut, and other organs, and clear definition of the separate functions of each cell system. The thymus-dependent development is represented morphologically by the small lymphocytes of the circulation and the white pulp type of development in the tissues. As in mammals, the thymus-dependent tissues of the chicken are basic to the ontogenesis of cellular immunity: graft versus host reactions, responses of delayed hypersensitivity and homograft rejection; and play a less clearly defined role in the antibody response to at least some antigens. Thymectomized-irradiated chickens are deficient in all these responses, and grow more slowly than any of the other experimental groups. In these animals germinal centers, plasma cells, and capacity for immunoglobulin synthesis remain intact. The bursa-dependent development is represented morphologically by the larger lymphocytes of the germinal centers and the plasma cells, and functionally by the immunoglobulins. Bursectomized-irradiated chickens are agammaglobulinemic and unable to produce detectable antibody despite intense, repeated stimulation with bovine serum albumin and Brucella abortus organisms. The thymus-dependent development in these animals seems to be normal; they have adequate numbers of lymphocytes in the circulation and tissues, are able to reject skin homografts, though more slowly than usual, and to exercise graft versus host reactions. The short life span of these chickens has precluded adequate study of responses of delayed hypersensitivity. There was no evidence of significant impairment of reticuloendothelial function in either the bursectomized-irradiated or the thymectomized-irradiated group, as judged by the clearance of colloidal gold and I(131)-tagged keyhole limpet hemocyanin.

Animals↗
PubMedDate not supplied

Identification of a T lineage antigen in the catfish.

A murine monoclonal antibody produced against catfish thymocytes and immunoglobulin-negative lymphocytes in the blood identified a catfish T cell antigen designated CfT1. The CfT1 antigen was found to be expressed on thymocytes, a subpopulation of the lymphoid cells in blood and other lympho-hemopoietic tissues, and a T cell line, but was not expressed by erythrocytes, thrombocytes, myeloid cells, B cells or macrophage cell lines. Stimulation of blood mononuclear cells with the T cell mitogen, concanavalin A, resulted in an increased frequency of CfT1+ cells. Conversely, lipopolysaccharide stimulation increased the number of IgM+ B cells and decreased the frequency of CfT1+ cells. The CfT1 antigen was defined as a single chain protein of M(r) 35,000 lacking N- and O-linked sugars. The CfT1 molecule thus provides a T lineage-specific marker in this bony fish representative.

Animals↗
PubMedDate not supplied

Improved strategies for postoligomerization synthesis of oligodeoxynucleotides bearing structurally defined adducts at the N2 position of deoxyguanosine.

Improved methodology has been developed for preparation of oligodeoxynucleotides bearing adducts on the N2 position of guanine in which the adduction reaction is carried out in homogeneous solution rather than while the oligonucleotide is immobilized on a solid matrix. The methodology utilizes a new synthon, 2-fluoro-O6-(trimethylsilylethyl)-2'-deoxyinosine (3). Nucleoside 3 is stable to the conditions of oligonucleotide synthesis, but the O6 protection is eliminated under very mild conditions following displacement of the 2-fluoro group by amine nucleophiles. Oligonucleotides containing 3 could be removed from the solid support by treatment with 0.1 M NaOH (8 h, rt) without disruption of 3. Reaction of the crude, partially deprotected oligonucleotide with (R)-2-amino-2-phenylethanol in homogeneous solution, followed by removal of the remaining protective groups with NH4OH (60 degrees C, 8 h) and then 0.1% acetic acid, gave the adducted oligonucleotide in good purity and yield. Alternatively, fully deprotected oligonucleotide containing 3 could be prepared by use of labile phenoxyacetyl-type protecting groups on the exocyclic amino groups.

Base Sequence↗
PubMedDate not supplied

Clonal origin of haematopoietic colonies in the postnatal mouse liver.

The liver of the neonatal mouse continues to show haematopoietic activity for up to 2 weeks after birth and morphological analysis has shown that this activity becomes focused in discrete haematopoietic colonies by the end of the first week postnatal. Furthermore, each colony contains cells of one haematopoietic lineage only, that is, erythroid, myeloid or pre-B-lymphoid cells. This pattern of differentiation suggests that each colony is derived from a single committed precursor cell, which, if true, would represent the first demonstration of non-mixed haematopoietic colonies in normal development and would provide a useful system for studying the factors affecting the clonal diversity of haematopoietic stem cells and their lineage-committed progeny. Here we have analysed the haematopoietic foci in the liver of neonatal mouse chimaeras, using a newly developed ubiquitous in situ cell marker system which clearly demonstrates the clonal origin of these colonies.

Animals↗