Biomedical subjects

S H Hamada

Publications and source records attributed to S H Hamada.

3 recordsLinked to original sources

PubMed1989

Cell surface changes during electromagnetic field exposure.

Fibroblasts from 5 1/2-day-old chick embryos go through a sequential series of changes when exposed to a constant electromagnetic field (EMF) of 10 V/cm. These changes include rounding up, becoming bipolar in shape, assuming a cylindrical profile, elongating perpendicular to the EMF, and migrating to the cathode. These morphological changes are associated with changes of the cell surface, which include the formation of filopodia and extensive sheet-like contacts on the cathodic cell surface, the retraction of processes and the formation of focal contacts on the anodic cell surface.

Animals↗

PubMed1979

Phagocytosis and resorption during the reassembly of dissociated embryonic cells of sea urchins.

Time-lapse and electron microscopic observations were made on both epithelial and mesenchymal cells during the reassembly of embryos from dissociated cells of Strongylocentrotus purpuratus. In epithelial cells, where lysosomes are produced through the fusion of saccules formed from Golgi bodies, both phagocytosis of cell debris and resorption of differentiated cell structures were observed. In these cells, the lysosomes migrate and fuse with both autosomes and phagosomes. On the other hand, in the mesenchyme cells, where lysosomes are produced through the direct enlargement of the Golgi body's cisterna, neither phagocytosis nor resorption was observed. The migration of the lysosomes to the epithelial cell margins is the first indication of a re-establishment of cellular polarity after dissociation.

Acid Phosphatase↗

PubMed1978

Cell migration during the reassembly of dissociated embryonic cells of sea urchins.

Disaggregated single cells from the embryos of Strongylocentrotus purpuratus were allowed to reaggregate and reform quasi-normal embryos in culture. In this investigation, emphasis was placed on cell migration and its role during cell segregation. Epithelial cell migration appears to be initiated through the sequential formation of (a) cytoplasmic blebs, (b) microvilli, (c) filopodia and (d) hyaloplasmic lamellae. After functioning as a locomotive structure during cell migration, the lamella enlarges and forms a hyaloplasmic sheet, which makes up part of the blastocoel wall. The blastocoel wall is the first recognizable structure reformed in the reassembling embryo.

Animals↗