Showing papers in "Differentiation in 1974"

TL;DR: The data obtained suggested that cellular contact between the two inductively correlated tissues was a prerequisite for the transmission mechanism while mitotic cell divisions were mainly responsible for the spread of the inductive message within the responding ectomesenchymal cells.

TL;DR: Cyclic AMP-elevating drugs appear to inhibit growth of guinea-pig epidermal cells and dermal flbroblasts by blocking the cell cycle in G−2, M1, or G.

TL;DR: Instead of chemotaxis, the concept of contact inhibition 1 provides a more satisfactory explanation for the distribution pattern of emigrating neural crest cells.

TL;DR: The ability of various steroids to induce maturation of Xenopus laevis oocytes after incubation or injection has been studied and the morphological and biochemical effects of the injection of the progesterone-receptor complex have been studied.

TL;DR: It is concluded that the induction of CPK is not dependent upon the formation of multinucleated myotubes, and both the brain and muscle isozymes are present in all cultures.

TL;DR: The results of morphological, cytological and functional investigations suggest that the expression of differentiation of ameloblasts is partially conditioned by collagen and/or associated mucopolysaccharides contained in predentin.

TL;DR: The coat phenotypes, and breeding results from known or presumptive XX/XX females, suggest that AKR and CBA cells were numerically balanced when melanoblasts and oocytes were formed during embryonic development, and therefore that the striking deviations from equality observed in mitotic populations of adult chimaeras arose later by differential proliferation or survival of AKR cells, or both.

TL;DR: The glycoproteins of the extracellular interface between the lens rudiment and the optic vesicle of the chicken embryo were demonstrated histochemically and their concentration was measured by microspectrophotometry through-out the period of lens induction, suggesting the involvement of matrix density increase in lens induction.

TL;DR: Intercellular bridges between blastomeres of the squid blastoderm apparently arise from the midbody and eventually break after becoming occluded by a ‘multi-layered membranous plug’.

TL;DR: The most effective treatment for preventing the action of TP was administration of MER-25 6 h before the injection of androgen, and sexual receptivity was significantly reduced in all groups compared with the oil-treated animals.

TL;DR: Rabbit antisera, prepared against new-born chick serum, revealed three foetus-specific proteins in foetal chicken serum, one of which was shown to be ovalbumin, which has some physiochemical properties in common with the mammalian α-foetoprotein.

TL;DR: The data suggest that sorting-out occurs in aggregates prepared from unincubated chick blastoderms, before the onset of gastrulation.

TL;DR: Biochemical and radioautographic data show that protein synthesis is increased markedly at the morula stage of rabbit development and in the late morula an increase in cytoplasmic ribosomes is observed, suggesting that ribosome availability may be rate-limiting for protein synthesis during cleavage.

TL;DR: Re-expression of aldolase B in vitro is correlated with chromosome loss; in vivo, the same correlation appears to exist, but in some cases the data are merely suggestive.

TL;DR: Autoradiographic studies of iris epithelial cells in vivo revealed a significant suppressive effect of irradiation on the frequencies of cells incorporating 3H-thymidine 7 and 14 days after lentectomy, and the possible mechanism of radiation-induced inhibition of lens regeneration is discussed.

TL;DR: To try to understand the mechanism of the dedifferentiation process which occurs during metaplastic transformation of iris epithelial cells into lens cells in newt lens regeneration, the activity of N-acetylglucosaminidase in iris and iri epithelium was studied as a function of time after lentectomy.

TL;DR: In this paper, a group of tetraparental AKR↔CBA/H-T6 mouse chimaeras were found to have an overwhelming preponderance of AKR mitoses.

TL;DR: It has been concluded that dissociated nerve cells cultivated in Rose chambers provide good experimental models for electrophysiological investigations.

TL;DR: It is concluded that the Th type is the morphological expression of the T lymphocytes, and the Bm type that of the B lymphocytes.

TL;DR: Modifications of the permeability at the plasma membrane or cell surface level comprise the major factor for AMD resistance, and there is no difference between resistant and sensitive cells in RNA polymerase sensitivity to AMD, nor in the capacity of chromatin to bind AMD.

TL;DR: It was demonstrated that the embryonic liver contains precursors of B cells, but not T helper cells, and the B precursor cells in the liver require a phase of differentiation and/or proliferation in the spleen to produce a detectable antibody response.

TL;DR: It is concluded that there is no other DNA synthesis, during maturation, than the continuation of the mitochondrial DNA synthesis which is already taking place during oogenesis, and that DNA synthesis is not required for successful maturation.

TL;DR: No differences in these parameters could be ascribed to the t12 gene in homozygous embryos or haploid sperm.

TL;DR: Using an anti-serum raised in rabbits against 12 week old human foetuses, foetal-specific materials were identified in bone marrow cells in a number of neoplastic and non-neoplastic conditions and high levels were found in patients with pernicious anaemia and folic acid deficiency and to a lesser extent, iron deficiency.

TL;DR: The possible effects on Cholinesterase development of combining muscle with dissociated spinal cord cells and with spinal cord explants, and of growing muscle in medium from which non-specific neural factors had been removed, were examined.

TL;DR: These experiments suggest that chondroblasts, cells notoriously sessile, contain considerable amounts of protein (or proteins) that binds ADP in a manner which is indistinguishable from actin, and this protein subserves functions other than those usually associated with contraction.

TL;DR: It was found that the microsomal fraction (mostly E.R.) is enzymatically related to, and is possibly in equilibrium with, a ‘post-microsomal’ lipoprotein fraction which does not present the same morphology as the conventional membrane in the livers of chicken embryos.