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F Jacob

Publications and source records attributed to F Jacob.

85 records · Page 5Linked to original sources
PubMed1976

Cell lines derived from teratocarcinomas.

A variety of cell lines have been isolated in vitro from transplantable teratocarcinomas. Some of them correspond to embryonal carcinoma (EC) cells. They are malignant and represent the stem cells from which all differentiated tissues derive in the tumor or in vitro. EC cells share some biochemical and antigenic properties with multipotential embryonic cells. From one of these EC cell lines, variants have been isolated in vivo and in vitro. Some are of EC type but restricted in their pattern of differentiation; others are altered in their tumorigenicity or in their antigenic characteristics. Another class of such variants corresponds to non-EC types. The most interesting ones correspond to tumoral lines of extra-embryonic tissues. All these cell lines constitute a valuable material for the study of mouse development and differentiation.

Acid Phosphatase↗
PubMed1976

[Anaphylactoid complications related to the use of 40,000- molecular weight dextran].

The intravenous administration of Dextran 40,000 (Rheomacrodes) was responsible in eight cases, for grave accidents, arising at the beginning of the injection. These were five cases of cardiovascular collapse and three of cardiac arrest. In 50 p. 100 of the cases, there was associated generalised erythma. The course was lethal in one case.

Anaphylaxis↗
PubMed1975

Structural similarities between a product of the T/t-locus isolated from sperm and teratoma cells, and H-2 antigens isolated from splenocytes.

Molecules specified by the H-2-linked T/t locus in the mouse are expressed on H-2-negative cells such as early embryos, sperm, and teratoma cells. By means of enzymatic radioiodination of cells and immunoprecipitation of lysates with congenic antiserum, one of these molecules, known as F9, has been obtained from sperm and teratoma cells and compared to H-2 isolated from murine splenocytes. Our studies indicate that both H-2 and F9 have identical molecular weights and subunit structure, including the presence of a B2-microglobulin-like subunit. These findings, taken together with previous studies of TL alloantigens, suggest that a number of gene products of the 9th linkage group show structural homology with each other and, in addition, with immunoglobulin. The genes in question may therefore have arisen from a primitive gene concerned with cellular recognition.

Animals↗
PubMed1975

Vitamin B12 nutrition and metabolism in the baboon (Papio cynocephalus).

1. Measurement of the vitamin B12 content of baboon tissues showed that the liver contained the highest concentration, followed by the pituitary, kidney, heart, spleen and pancreas. 2. The dietary vitamin B12 requirement of the baboon for the maintenance of satisfactory body stores was between 1 and 2 mug/d. 3. Satisfactory liver vitamin B12 stores were invariably associated with serum levels above 125 pg/ml, whereas liver levels were usually low when the serum level was below 50 pg/ml. 4. Increased methylmalonic acid (MMA) excretion after a valine load occurred when the liver vitamin B12 level was less than 0-40 mug/g. L- and DL-valine were approximately equally effective as precursors of MMA, whereas sodium propionate, whether given orally or intraperitoneally, was less effective. 5. The distribution of radioactivity along the wall of the intestinal tract after an oral dose of [57-Co]cyanocobalamin suggested that the distal half of the small intestine was the main site of vitamin B12 absorption. However, the utilization of vitamin B12 put direct into the middle part of the small intestine was much lower than that of an oral dose. 6. The unsaturated vitamin B12-binding capacity of baboon serum was not related to the serum vitamin B12 level. There was a significant difference between the unsaturated vitamin B12-binding capacities of the two subspecies of baboon (Papio cynocephalus cynocephalus and P. cynocephalus anubis) studied.

Animal Nutritional Physiological Phenomena↗
PubMed1975

[Mouse teratocarcinoma: differentiation in cultures of a multipotential primitive cell line (author's transl)].

A line of primitive cells of teratocarcinoma is able of differentiating during in vitro cultures. The differentiated cell types correspond to derivatives of the three germ layers. They appear according to a reproducible schedule. The differentiated cell types exhibit a normal karyotype. They have lost their tumorigenicity and have a limited life span. Agregates containing various numbers of primitive cells have been prepared and plated in culture dishes. Their study shows that the first differentiated cell types appear only when the agregates are greater than a certain critical mass. Primitive cells carry on their surface the F9 but not the H-2 antigen. During differentiation in culture, the H-2 antigen appears rapidly on certain cells. The fraction of H-2-carrying cells increases as a function of time while that of F9-carrying cells decreases.

Animals↗
PubMedDate not supplied

Diversity of the mechanisms of resistance to beta-lactam antibiotics.

The sensitivity of a bacterium to beta-lactam antibiotics depends upon the interplay between 3 independent factors: the sensitivity of the essential penicillin-binding enzyme(s), the quantity and properties of the beta-lactamase(s) and the diffusion barrier that the outer-membrane of Gram-negative bacteria can represent. Those three factors can be modified by mutations or by the horizontal transfer of genes or portions of genes.

Anti-Bacterial Agents↗
PubMedDate not supplied

AIDS agreement.

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France↗