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Biomedical subjects

J M Yoffey

Publications and source records attributed to J M Yoffey.

At least 37 records · Page 2Linked to original sources
PubMed1977

Comparison of RNA and DNA synthesis, spontaneous and PHa induced, between blood lymphoid cells of newborn infants, older infants, and adults. A study of scintillation counting and by autoradiography.

Spontaneous and PHA induced RNA and DNA synthesis was measured qualitatively by autoradiography and quantitatively by scintillation counting in blood lymphoic cells of newborn infants, older infants, and adults. Spontaneous RNA synthesis was found in transitional cells, large phagocytic lymphoid cells and lymphocytes. Transitional cells and phagocytic lymphoid cells also synthesized DNA spontaneously. Quantitatively, spontaneous RNA synthesis was active in both newborn infants and in adults, but significantly less so in older infants. PHA stimulation for 18 h increased RNA synthesis significantly in blood lymphoid cells of newborn infants and adults, and to a much lesser but still significant degree in older infants. Spontaneous DNA synthesis was significantly greater in newborn infants than in older infants and adults. PHA stimulation for 18 h had no effect on thymidine incorporation in any of the groups studied.

Adult↗
PubMed1977

Establishment in continuous culture of a new type of lymphocyte from a "Burkitt like" malignant lymphoma (line D.G.-75).

The isolation and establishment in vitro of a hitherto undescribed type of lymphocyte designated D.G.-75 is reported. The original inoculum was derived from the pleural effusion of a child with a primary abdominal lymphoma, which clinically and histologically resembled Burkitt's lymphoma. In addition to the absence of the EBV genome and EBV receptors, this line possesses a number of other properties which distinguish it from previously described lymphoblastoid cell lines. It has different growth characteristics and morphology; does not form EAC or E rosettes (representative of B and T) cell surface markers, respectively); possesses IgM-kappa immunoglobulins on the cell surface (B lymphocyte), has an unusually high cap-forming ability and low agglutinability with fluorescent concanavalin A. One homologue of the No.14 chromosome pair possesses extra chromatin material as revealed on chromosome banding. This abnormal chromosome marker is similar to that described in biopsies and cultured tumor cells from patients with African Burkitt's lymphoma.

Agglutination Tests↗
PubMed1976

Cytoplasmic DNA synthesis by cord blood cells of premature and full-term infants: an autoradiographic study.

Cord blood cells from 8 full-term and 12 premature infants as well as blood leukocytes from 10 adults were incubated with 3H-thymidine and were subsequently exposed to autoradiographic emulsion for prolonged periods of 45 and 90 days. Cytoplasmic label -- which were interpreted as evidence of mitochondrial DNA synthesis -- was found in 1.7 per cent of lymphoid cells from adult blood, in 2.9 per cent and 4.5 per cent of lymphoid cells from full-term and premature infants, respectively. Statistical analysis of the data shows that the number of labelled cells is significantly larger in the blood of premature infants than in adults (p less than 0.01).

Adult↗
PubMed1975

Cells in spontaneous DNA synthesis in cord blood of premature and full-term newborn infants. An autoradiographic study.

Cord blood from 16 premature infants and 10 full-term infants, and blood from 10 healthy adults, was incubated for 30 minutes with tritiated thymidine, after which an autoradiographic study was made of spontaneously labeling cells. Apart from a varying number of erythroblasts, myelocytes, and an occasional blast cell, two main types of spontaneously labeling cells were observed: transitional cells and large lymphoid cells, previously shown to be phagocytic. Spontaneously labeling cells were 12 times more frequent in cord blood of premature and full-term infants than in the blood of adults. No transitional cells were seen in adult blood.

Autoradiography↗
PubMed1975

Phagocytic cells in cord blood.

A suspension of fine carbon particles was added to cord blood of healthy premature and full-term infants, and the mixture was incubated for 3 h, after which the uptake of carbon particles by blood leukocytes was examined. The results were compared with those from the blood of adults. A gradient of phagocytic activity was observed. The most active uptake of carbon was by the leukocytes of premature infants, the least active by leukocytes of adults. In cord blood and blood of adults, phagocytic activity was evident in both monocytes and neutrophils. In addition, two types of what have been termed 'lymphocytoid' phagocytes were seen. These resemble lymphocytes in their morphology. One type possesses basophilic cytoplasm, and has been found only in premature cord blood. The presence of lymphocytoid phagocytes affords a further indication of the differences between the circulating lymphocyte population in the prenatal and perinatal period as compared with the adult.

Carbon↗
PubMed1975

Bone marrow lymphocytes.

Some aspects of bone marrow lymphocyte production are reviewed. Attention is drawn in particular to fundamental histogenetic differences in the production of B and T lymphocytes. B lymphocyte precursors are transitional cells.

B-Lymphocytes↗
PubMed1975

Histogenesis of B and T lymphocytes.

There are striking differences in the histogenesis of B and T cells. 1) The formation of B lymphocytes seems to be closely associated with that of other blood cells, whereas the formation of T cells is not. 2) In postnatal life, the bone marrow is a mojor site for the formation of B cells, while T cells are produced mainly in the thymus. 3) B cells are formed in a short production pathway, consisting of two or three mitoses, whereas T cells are formed in a long production pathway, consisting of about eight mitoses. 4) The starting point for the short production pathway is a large transitional cell. The long production pathway starts with a reticulum cell, a large lymphoblast or a cell which has been termed "monocytoid". 5) Plasma proteins have ready access to the cells of the short production pathway in bone marrow, but because of the blood-thymus barrier are not as readily accessible to the tissure involved in T cell formation in the long production pathway in the thymus.

Age Factors↗
PubMed1970

Peyer's patches: immunologic studies.

The immune capabilities of the Peyer's patches have been investigated by the use of an in vitro system. Despite our failure to stimulate Peyer's patch lymphocytes in vivo it appears that Peyer's patches behave immunologically as peripheral lymphoid tissues. Cultures prepared from the dissociated Peyer's patches of normal rabbits respond to sheep erythrocytes. The response is comparable to that obtained with spleen cultures from the same animals and is not dependent on the presence of the epithelial cells which line the lumen. Similar thymic cultures do not respond. Our experiments with cultures prepared from rabbits which have received one or two injections of SRC show that the Peyer's patches contain both IgM and IgG "memory" cells which have migrated from the spleen. The concentration of these cells in the spleen remains several hundredfold higher.

Animals↗