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Biomedical subjects

D Solter

Publications and source records attributed to D Solter.

At least 127 records · Page 7Linked to original sources
PubMed1977

Ultrastructural localization of membrane phosphatases in teratocarcinoma and early embryos.

Ectodermal cells of the two- and three-germ layer-thick mouse egg-cylinders are considered to be the progenitors of embryonal carcinoma cells in embryo-derived teratocarcinomas. In an attempt to find differences between the tumor cells and equivalent embryonic cells, we have studied the electron microscopic cytochemical localization of alkaline phosphatase, 5'-nucleotidase, and Mg2+-activated adenosine triphosphatase (ATPase) in embryo-derived teratocarcinomas and mouse egg-cylinders. Alkaline phosphatase was detected in both embryonic and tumor cells, but its activity appeared much more intense in the tumor cells. No ATPase was demonstrated in embryonic ectodermal cells of 6-day-old embryos and only in occasional cells of 7- and 8-day-old embryos. No 5'-nucleotidase activity could be demonstrated in 6- to 8-day-old cylinders. There was marked ATPase and 5'-nucleotidase activity in the membranes of embryonal carcinoma cells. These data point out some differences on the plasma membrane between the embryonal carcinoma cells and equivalent embryonic cells. The potential significance of these differences is discussed with regards to the transformation of embryonic cells in tumor cells. (Am J Pathol 87:297-310, 1977).

Adenosine Triphosphatases↗
PubMed1977

[Treatment of fractures of the femoral shaft].

The femoral shaft fracture, although not frequent, is still a severe injury. In this work 367 fractured femoral shafts treated during the last six years are reviewed. Three hundred and forty-seven patients were treated by operation of whom 276 were treated with intramedullary nail and previously boring of the medullar channel, almost all of them by open reduction. In 59 cases compression plate was applied. In the same time 20 femoral shaft fractures were treated conservatively. Amoung other complications infection and pseudoarthrosis should be particulary mentioned which occurred in 5,2% and 3,3% respectively. The comparison between operative and conservative menagement was done by analysis of final results which included duration of the treatment and period necessary for the restitution of the function. On the basis of these results the authors conclude that majority of femoral fractures should be treated by intramedullary nailing.

Adult↗
PubMed1976

Ultrastructural localization of cytoplasmic phosphatases in preimplantation mouse embryos.

The appearance and localization of the cytoplasmic phosphatases [acid phosphatase (AcPase) as a marker of lysosomes, TPPase as a marker of the Golgi apparatus, and NDPase (IDPase) as enzymatic marker of the endoplasmic reticulum (ER)] were cytochemically studied on the ultrastructural level in secondary oocytes and in preimplantation mouse embryos. The detectable AcPase activity, located on the inner surface of the membrane delimiting some cytoplasmic vacuoles (lysosomes and autophagic vacuoles), appears at the eight-cell stage and grows pregressively stronger up to the blastocyst stage. Golgi-associated reaction for TPPase was detectable in oocytes, dropped in one-cell embryos and became negative in the two-cell embryos. The reaction for TPPase and IDPase was present in plasma membranes of oocytes and early embryos and appeared in the delimiting membrane of some cytoplasmic vesicles in eight-cell embryos. Some activity of IDPase was found in small segments of the ER at the morula and blastocyst stage. The observed results suggest that the lysosomes are the first organelles in early embryos showing activity of the marker enzymes of the phosphatase type, while the activity of other marker enzymes is mainly concentrated in the plasma membrane of blastomeres. It cannot be excluded, however, that positive reaction for TPPase and IDPase in the plasma membrane results from nonspecific action of other phosphatases.

Acid Phosphatase↗
PubMed1975

Mouse embryo development in vitro: effects of inhibitors of RNA and protein synthesis on blastocyst and post-blastocyst embryos.

The effect of inhibitors of RNA synthesis (Cordycepin, Actinomycin D) and protein synthesis (Cycloheximide) on the development and growth of mouse blastocysts in vitro was explored. Blastocysts exposed in vitro for 24 hours to 50 mu-g/ml Cordycepin, 0.005 mu-g/ml Actinomycin D, or 0.1 mu-g/ml Cycloheximde grew and began to attach to the dish in the similar manner as did the controls. Cell number, 3-H-thymidine-labeling index and mitotic index in treated blastocysts were also similar to controls. Cell number, 3-H-thymidine-labeling index and mitotic index in treated blastocysts were also similar to controls. Control blastocysts grown in vitro for six days attached to the dish, trophoblastic layer was spread and inner cell mass continued to grow and formed an egg-cylinder like structure. Blastocysts grown in constant presence of 50 mu-g/ml of Cordycepin in themedium or those exposed to inhibitor only for the first 24 hours failed to develop inner cell mass derivatives in culture, although the growth of trophoblastic cells was as in controls. The same results were obtained if blastocysts were exposed to 0.005 mu-g/ml of Actinomycin D or to 0.1 mu-g/ml of Cycloheximide either continuously or for the first 24 hours. Higher concentrations of Actinomycin D (0.05 mu-g/ml) or Cycloheximde (1 mu-g/ml) were toxic for the blastocysts causing their degeneration within 24-48 hours. Our results suggested that appropriate concentrations of RNA or protein synthesis inhibitors could prevent the development of inner cell mass derivatives with essentially no effect on the development of primary trophoblast. This would indicate that the process of differentiation of inner cell mass cells is much more sensitive to metabolic inhibitors than the differentiation of giant trophoblastic cells.

Animals↗
PubMed1975

Immunosurgery of mouse blastocyst.

Mouse blastocysts with and without zonae pellucidae are susceptible to complement-dependent antibody cytotoxicity. Exposure of blastocysts to rabbit anti-mouse serum together with complement results in the death of all cells; however, when blastocysts are exposed to antiserum alone and then transferred to guinea pig complement, only the trophoblastic cells are killed. These results suggest that the mouse blastocyst is not permeable for certain antibodies. The inner cell masses can easily be separated from the remnants of trophoblastic cells and are then able to grow and differentiate in vitro. This method of immunosurgery can be used to obtain large quantities of pure inner cell masses in a relatively short period of time.

Animals↗