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Biomedical subjects

M Solursh

Publications and source records attributed to M Solursh.

At least 145 records · Page 8Linked to original sources
PubMed1978

A scanning electron microscope study of cell shape and cell appendages in the primitive streak region of the rat and chick embryo.

This report provides a scanning electron microscopic account of cell shapes and cell appendages that are observed in the primitive streak region of the rat and chick embryos. Epiblast cells become progressively elongated in the primitive streak region until flask cells predominate medially. The flask cells have a broad basal end directed toward the endoderm. In addition to fine filopodia, broad lamellipodia are found anchoring the flask cells to subjacent cells. The primary mesenchyme cells are at first round in shape and closely packed, but laterally are flattened and more dispersed. The mesenchyme cells are associated with each other by filopodia and lamellipodia and with the epiblast and endoderm by filopodia. On the basis of this description it is suggested that cell movement through the primitive streak occurs by cell extension, attachment by basal lamellipodia, and cell shortening that results in the movement of individual cells in a cell stream.

Animals↗
PubMed1978

Regional differences in mesenchymal cell morphology and glycosaminoglycans in early neural-fold stage rat embryos.

Rat embryos with two to four pairs of somites (day 9 of gestation) were examined by scanning electron microscopy and Alcian blue staining. The neural folds, which represent only future brain region at this stage, form a pair of elongated hemispheres with a deep neural groove between them. In transverse section the neural ectoderm is biconvex; the cranial mesenchyme cells beneath them are widely separated by extracellular matrix (ECM) and are joined to each other and to the ectodermal basement membrane by fine cytoplasmic processes and strands of ECM material. In contrast, mesenchyme cells close to the primitive streak are closely packed, having broad areas of surface contact and only small amounts of ECM. The nature and distribution of ECM, cell surface, and basement membrane glycosaminoglycans (GAG) were investigated by staining with Alcian blue at specific pH values in combination with enzyme pretreatments, and at various critical electrolyte concentrations. The results indicate that the GAG of the ectodermal basement membrane, mesenchymal ECM and mesenchymal cell surfaces are in continuity with each other and consist largely of hyaluronate and chondroitin sulphates. Differences in morphology and histochemistry of neural fold and primitive streak regions are discussed in relation to their possible morphogenetic significance.

Animals↗
PubMed1975

An effect of accumulated matrix on sulfation among cells in a cartilage colony: an autoradiographic study.

In this report an autoradiographic approach is used to compare synthetic activities of cells within differentiated cartilage colonies. While amino acid incorporation is umiform throughout the colony, H-3-uridine is incorporated more actively by cells having little matrix, cells which are typically in the peripheral regions of a colony. On the other hand S-35-O4 is incorporated most actively by cells in the colony centers. This difference in sulfation appears to occur independently of the mitotic state of the cells, since it is apparent in both growing and near-stationary cultures. Instead, there is a correlation between the accumulation of extracellular matrix and more active levels of sulfation. In support of the idea that matrix creates a microenvironment more favorable to chondrogenesis is the observation that a brief treatment with hyaluronidase, which removes about 60% of the S-35-O4 from prelabeled cultures, depresses isolation of labeled glycosaminoglycans. The possible role of extracellular matrices in altering the expression of differentiated functions by creating a more favorable microenvironment is considered.

Amino Acids↗
PubMed1975

Determination of limb bud chondrocytes during a transient block of the cell cycle.

The process of determination is studied by using a cell culture system derived from dissociated chick embryo limb buds. When limb bud cells obtained from embryos younger than stage 25 (undertermined) are temporarily prevented from passing through the cell cycle (either by maintaining the cells on a petri dish or in the presence of high concentrations of cyclic AMP, both of which depress thymidine-H(3) incorporation), some cells subsequently form cartilage colonies. These results support the hypothesis that a temporary block at some stage in the cell cycle causes mesoblasts to acquire the capacity to differentiate into cartilage cells.

Aminopterin↗