(n.) The structureless, protoplasmic tissue of the embryo; the primitive basis of an organ yet unformed, from which it grows.
Example Sentences:
(1) They are capable of synthesis and accumulation of glycogen and responsible for its transfer to sites of more intense metabolism (growth, bud, blastema).
(2) Blastemas implanted with 2 dorsal root ganglia and simultaneously denervated 14 days after amputation exhibited control levels of cell cycle activity 6 days later, as measured by 3H-thymidine pulse labeling.
(3) A search for specific proteins involved in newt limb regeneration, using monoclonal antibodies against forelimb blastemas, led to the detection of an antigen in the regenerate epithelium.
(4) Between different tumours, heterogeneity in the degree of epithelial differentiation in the blastema was found.
(5) After amputation, limbs of both early and late stages form a regenerative blastema and support lens formation from the outer cornea.
(6) More difficult are clear therapeutic recommendations for the very rare forms of endocrinically active genital tumors which stem from sex cords or which are composed of different components of the complex ovarian blastema.
(7) By 15 days, a dense accumulation of blastema cells is present beneath the apical cap, and these cells are preferentially oriented in a circumferential direction.
(8) Not all cells of the adult newt blastema are randomly distributed and actively progressing through the cell cycle.
(9) Thus, it appears that denervation of medium-bud-stage limb blastemas promotes the lengthening of G1 and premature exiting of cells from the cycle into the G0-1 phase.
(10) Computer-assisted morphometric analysis showed only minor differences between proximal tubular cells from 18-day embryos and tubular cells from 7-day cultures of blastema taken from 11-day embryos.
(11) In the absence of skin, epidermal wound healing failed to occur and blastemas could not develop.
(12) At the contact between the ureter and the mesonephretic blastema, the cells of the primary ureter have special characteristics: existence of an abundant "coat", numerous "villous processes" and a dense network of fibres of collagen.
(13) Serial angiograms and tissue biopsies documented the transition from nodular renal blastema to Wilms' tumor.
(14) After amputation, NvKII mRNA is expressed both in proximal and distal blastemas, although at higher levels distally, indicating that this keratin is regeneration associated.
(15) Since others have shown that denervation at the time of amputation blocks subsequent mitosis in internal stump tissues yet allows normal levels of DNA synthesis for eight days, we conclude that X-irradiation and denervation prevent cell division in potential blastema cells by different mechanisms.
(16) In a study of 71 female foetuses, gonadal blastema was observed at 1.5 cm crown rump length (CRL).
(17) Furthermore, staining with three fucose-binding lectins revealed that the linkage between terminal alpha-fucose residues to the constituent oligosaccharide chains varied between epithelial cells, blastema and stroma.
(18) However, in differentiation phase blastemas, laminin immunoreactivity was concentrated in specific locations.
(19) The fasciculata cells are the direct continuation of the subcapsular blastema.
(20) These results indicate that the limb tissues of the early stage limbs contain non-neural inductive factors at a low level and that after limb amputation and blastema formation the level of these factors becomes high enough to promote lens formation from implanted cornea, even after denervation.
Blastemal
Definition:
(a.) Relating to the blastema; rudimentary.
Example Sentences:
(1) (2) Septa and the papillonodules, when present, are the only solid portion of the tumor and contain blastemal cells admixed with their normal and aberrant derivatives.
(2) Both the characteristic pattern of epidermal mitotic stimulation which normally follows amputation and the later increase in blastemal mitoses are suppressed by irradiation.
(3) When epithelium-free blastemal mesenchyme is grafted onto injured flank musculature, ectopic limb regeneration occurs and the AEC derived from flank epidermis exhibits mAb 9G1 reactivity.
(4) The histologic analysis of the patient's tumor, including both light and electron microscopic analysis, indicated that this tumor satisfies the histologic criteria for an adult Wilms' tumor, namely, blastemic cells that are immature renal parenchymal cells, embryonic tubular structures, and a scanty stromal component consisting of loosely arranged spindle cells.
(5) Recent work has demonstrated that denervated blastemal cells accumulate in the G1 phase of the cycle.
(6) Using microdensitometry techniques the points in the cycle where blastemal cells become blocked after X-irradiation or denervation of the regenerating amphibian limb have been identified.
(7) In-situ-hybridization allowed precise localization of the markedly increased IGF-II mRNA to blastemal cells.
(8) In Wilms' tumour, binding of PAL-E was not restricted to the endothelium; staining of blastemal cells was observed in seven out of eight cases examined.
(9) The PNA stained the surface of the blastemal cells after sialidase digestion in the original tumor, heterotransplants, and cultured cells.
(10) The thicker underlying reticular lamina was markedly attenuated in these regions near the blastemal apex.
(11) After amputation of the limb of an adult urodele amphibian at any point along the proximodistal axis, blastemal cells (the progenitor cells of the regenerate) give rise only to the missing structures.
(12) The abortive blastems disappear only slowly, because the degeneration of their neoblasts is partly compensated by the continual immigration of new regeneration cells which come from the posterior region.
(13) Such regressions were followed by blastemal formation and middle- to late-bud blastemas were found at the end of 11 or 14 days treatments with retinol palmitate.
(14) Wilms' tumour (nephroblastoma), a childhood embryonal kidney tumour, is believed to arise from malignant transformation of abnormally persistent metanephric blastemal cells.
(15) Blastemal cells from the central portion of the regenerate were observed at varius stages of chrondrogenesis with those immediately beneath the wound epithelium least advanced in this respect.
(16) The molecular weights of the newt proteins detected by these antibodies are very similar to those of human keratins 8 and 18, further supporting the immunocytochemical evidence that the newt homologs of these keratins are expressed in blastemal cells.
(17) To better characterize the cells involved in newt limb regeneration, blastemal cells from accumulation and differentiation phase blastemas were grown in dissociated cell culture, and their morphology and antigenic phenotype determined using a variety of antibodies directed against intermediate filaments, cell adhesion molecules, and extracellular matrix molecules.
(18) However, blastemal cells demonstrated coexpression of CYTO and VIM intermediate filaments when grown in a serum-free medium on a matrix material.
(19) The effects of vitamin A on blastemal epidermis were studied during the early postamputational period of forelimb regeneration in Triturus alpestris.
(20) These observations emphasize the potential value of a monoclonal anti-polysialic acid antibody in identifying blastemal metanephric cells and their epithelial differentiatives in Wilms' tumor.