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Biomedical subjects

F Jacob

Publications and source records attributed to F Jacob.

At least 55 records · Page 3Linked to original sources

Carbohydrate structure and cell differentitation: unique properties of fucosyl-glycopeptides isolated from embryonal carcinoma cells.

From embryonal carcinoma cells labeled with fucose, two main classes of glycopeptide products of Pronase digestion can be distinguished by Sephadex G-50 column chromatography: one eluted near the excluded volume and a smaller one. The large fucosyl-glycopeptides are scarcely present in differentiated cells derived from embryonal carcinoma cells (i.e., fibroblastlike cells, myoblasts, and parietal yolk-sac carcinoma). During in vitro differentiation of embryonal carcinoma cells, these large glycopeptides disappear almost completely. The small glycopeptides were analyzed by paper electrophoresis, concanavalin A-Sepharose affinity chromatography, and digestion with an endoglycosidase. The major components of these glycopeptides from embryonal carcinoma cells appear to be different from complex glycopeptides known to occur in adult cells. The glycopeptide pattern of mouse preimplantation embryos resembles that of embryonal carcinoma cells. These results suggest that the carbohydrate profile changes fundamentally during early stages of mammalian development.

Cell Differentiation

Metabolic cooperation between mouse embryonal carcinoma cells and their differentiated derivatives.

Metabolic cooperation has been used as an index of intercellular communication between mouse embryonal carcinoma (EC) and other cell types. EC cells do not cooperate with differentiated cells of various properties or origins. In contrast they cooperate with cells of all other EC lines tested, including a human teratocarcinoma line, but with different efficiencies. This might reflect differences either in cell-cell interactions or in the formation of gap junctions. During in vitro differentiation, EC cells appear to remain isolated from differentiated cell types.

Cell Adhesion

Absence of reaction of a xenogenic anti-H-2 serum with mouse embryonal carcinoma cells.

A rabbit antiserum raised against papain-solubilized H-2 antigens has been used to investigate the eventual expression of H-2 antigens and related molecules on embryonal carcinoma cells and on other types of mouse cells. No material reacting with this serum could be detected on cells carrying the F9 antigen. It is concluded that no H-2 antigen or cross-reacting material is expressed on these cell types.

Animals

The presence of F9 antigen on the surface of mouse embryonic cells until day 8 of embryogenesis.

The fate of F9, a surface antigen common to embryonal carcinoma cells and cleavage embryos, as well as to male germ line cells has been studied in post-implantation mouse embryos. The antigen is readily detected on the surface of 7-day and 8-day, but not on 9-day embryonic cells, using anti-F9 serum absorption experiments and indirect immunofluorescence staining. In addition, it is shown that an anti-F9 serum absorbed with 8-day (but not with 9-day) embryonic cells does not react with cleavage embryos (morulae). It is concluded that the antigenic determinants, which are recognized on the surface of morulae by the anti-F9 serum, persist until day 8 of embryogenesis, but are not detected on day 9, either due to their absence, masking or quantitative reduction.

Animals

Idiopathic dilatation of the right atrium revealed in childhood by dysrhythmias.

A 7-year-old male presented with apparently banal but repetitive episodes of paroxysmal supraventricular tachycardia, along with other manifestations of atrial hyperexcitability. Isolated dilatation of the right atrium was discovered. This disorder is usually latent or benign, but sometimes it is serious because of conduction defects. Lack of relevant studies means the basis of the disorder is not understood.

Cardiomegaly

Surface antigen in early differentiation.

Addition of Fab fragments from rabbit antiserum to surface antigen F9 to 2-cell stage mouse embryos in culture does not alter cleavage; however, the addition prevents culture does not alter cleavage; however, the addition prevents the formation of compact morulae and blastocysts. A similar effect is observed when Fab fragments are added to already compact 8-cell stage or even older morulae, but disappears at the beginning of blastocoel formation. This effect is reversible: uncompact 30-cell embryos washed free of Fab become compact in a few hours, produce blastocysts, and upon reimplantation into pseudopregnant mothers can produce mice. Development is not altered by divalent anti-F9 antibodies, by Fab fragments from sera directed against other embryo surface antigens, or by succinyl concanavalin A.

Animals

Sparing effect of folic acid deficiency on the development of vitamin B12 deficiency in baboons fed a vitamin B12 deficient diet.

The effect of a vitamin B12 and folic acid deficient diet on juvenile and adolescent baboons (Papio cynocephalus anubis) was studied. The baboons developed clinical and hematological signs characteristics of folacin deficiency, although they were less severe in juvenile baboons. The signs disappeared when folic acid was replaced in the diet. The serum vitamin B12 levels increased in all baboons fed the vitamin B12 and folic acid deficient diet. When folic acid was added to the diet, the levels gradually decreased in adolescent baboons, liver vitamin B12 levels decreased to a lesser extent when fed a vitamin B12 and folic acid deficient diet than when fed a vitamin B12 deficient diet. In juvenile baboons fed a vitamin B12 and folic acid deficient diet, for 7 months and a vitamin B12 deficient diet for a further 11 months, liver vitamin B12 levels did not decrease at any time but were similar to those in baboons fed a vitamin B12 and folic acid supplemented diet.

Aging

Absorption analysis of H-2D and K antigens on spermatozoa.

The presence of H-2D and K antigens on mouse spermatozoa has been investigated by absorption followed by testing on the proper target lymphocytes. It is concluded that, in addition to Ia antigens, H-2D and K antigens are indeed expressed on mouse sperm cells.

Animals