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S Sheldon

Publications and source records attributed to S Sheldon.

45 records · Page 3Linked to original sources
PubMed1985

A simple and rapid method for the detection of lymphocytotoxic antibodies using cell panels frozen on Terasaki plates.

A 40 cell panel of lymphocytes selected for HLA-A,B and DR antigens, frozen in Terasaki microtest trays can be used routinely to identify the presence of specific HLA antibodies within two hours. Blind testing using well defined HLA typing sera showed that specificities could be identified to a high degree of significance using this method. The method has proved successful for screening for T cell, including HLA-A,B and B cell, including HLA-DR antibodies. The method is particularly useful for the routine tissue typing laboratory as the frozen panel can be used without the need for complicated and time-consuming cell washing procedures which have been the downfall of previously published methods.

Antilymphocyte Serum↗
PubMed1982

Catabolic half-lives and antigenic relationships of native, altered and commercially prepared human albumins in rabbits.

As determined in rabbits, the in vivo plasma survival, i.e. half-life (t 1/2), of albumin produced by the cold-ethanol procedure did not differ significantly from that of native albumin (p less than 0.5). Plasma survivals of reprocessed and heat-ethanol produced albumins were significantly less than that of the native protein (0.02 less than p less than 0.05). Chemically-modified albumin had a considerably reduced t 1/2 (p less than 0.001) and was the only albumin shown to be antigenically different from the native protein. Variations in t 1/2 s of albumin preparations could not be attributed to differences in their polymer contents.

Animals↗
PubMed1981

Comparison of the patterns of chromosomal late replication. I. Human renal epithelium and lung fibroblasts in vitro.

The patterns of late replication of human fetal lung fibroblasts and renal epithelium in culture were compared using a terminal pulse of 3H-TdR or of BrdU followed by autoradiography or Hoechst and Giemsa staining, respectively. Fifty cells from each of two fetuses were scored with each technique. Statistically significant quantitative differences were found in the pattern of late replication of the two tissues, but these differences were not consistent between the two individuals. In cultures from both of the fetuses examined, the autoradiographic grain counts over a given segment of chromosomes 1, 4, and 5 in the two tissues were shown to differ by a factor of 2 or more, while with BrdU chromosomes 1, 2, 4, and 13 had a labeling frequency that differed by 20% or more over a given band. The results suggest that although there are tissue-specific differences in the patterns of late replication, these differences do not reflect changes in the state of differentiation.

Autoradiography↗
PubMed1981

Comparison of the patterns of chromosomal late replication. II. Chick embryo lung and kidney in vivo and in vitro.

The patterns of late replication were compared on direct chromosomes preparations from cells of chick embryo lung and kidney, as well as in cultures established from these tissues using tritium autoradiography. Fifty cells from each tissue were examined from each of five animals in vivo and three in vitro. Two- to four-fold differences in the frequencies with which a chromosome arm labeled were seen when lung and kidney were compared; however, labeling differences were often equally significant in the opposite direction when cells from another chick embryo were analyzed. The results obtained in vivo were comparable to those seen in vitro, indicating that cell-culture did not alter cell differentiation in a way that could be detected by late replication patterns. Variation in tissue-specific differences in late replication between individuals suggests that these patterns do not reflect differences in the differentiated state.

Animals↗
PubMed1981

Continued presence of nucleoli in human germ cell tumors during mitosis.

A series of human germ cell-derived tumors were examined for the presence of nucleoli which persist through mitosis. Embryonal carcinomas, seminomas, and the cytotrophoblasts of choriocarcinomas had persistent nucleoli in more than 70% of mitoses. The differentiated cells derived from embryonal carcinomas, endodermal sinus tumors, and the more differentiated elements of choriocarcinomas only rarely had persistent nucleoli. These nucleoli appeared to remain transcriptionally active.

Cell Nucleus↗
PubMed1979

Scintillation fluid shortens exposure times in autoradiography.

Premixed, commercially available scintillation fluids were used to reduce exposure time of tritium (3H) and iodine-125 (125I)-labeled whole cells, and of 3H-labeled Giemsa-banded chromosome preparations. Emulsion-coated slides were dipped into scintillator for no longer than 2 min and exposed in the dark at 4 degrees C. Maximal values for percentage of human diploid cell (WI-38) nuclei labeled with 3H-thymidine of moderate specific activity were obtained in 12 hr. Without scintillator the exposure time was 4 days. Exposure time for cells labeled with 125I-serum was reduced from over 90 days to 14 days. The shortened exposure time for banded chromosomes permitted successful prestaining with Giemsa, a sequence that is not possible without scintillator.

Autoradiography↗