Biomedical subjects

S G Phillips

Publications and source records attributed to S G Phillips.

22 records · Page 2Linked to original sources

PubMed1971

Nucleoli of diploid cell strains. Thei normal ultrastructure and the effects of toyocamycin and actinomycin D.

Nucleoli of cultured Chinese hamster or mouse cells in early passages had a loosely reticular substructure. Within the reticulum small, irregularly shaped, light fibrillar zones occurred which were contiguous with denser fibrillar zones. These denser zones appeared to be connected in some places to the particulate material which composed the mass of the nucleolus. Generally, electron-transparent spaces separated the particulate zones from the fibrillar areas. Treatment with toyocamycin, an agent which is reported to cause a blockage in the processing of ribosomal RNA, greatly inhibited the accumulation of newly synthesized RNA in the cytoplasm, as monitored by radioautography. Toyocamycin treatment caused the gradual disappearance of the granules from the particulate region of the nucleoli, and resulted ultimately in the nucleoli appearing homogeneously fibrillar. Actinomycin D treatment, which inhibited virtually all RNA synthesis, caused a segregation, and finally a disaggregation, of nucleolar components.

Animals↗

PubMed1971

Distinctive characteristics of nucleoli of two established cell lines.

Nucleoli of cultured cells of the established lines KB and L were found to possess a distinctive fine structural organization. The major portion of the nucleolar volume was composed of compact, particulate material. Spheroidal fibrillar zones about 0.4 micro in diameter occurred within the particulate mass. These fibrillar zones had a central light area and a denser rim. Toyocamycin treatment, which sharply inhibited the appearance of newly synthesized RNA in the cytoplasm, caused the gradual disappearance of the fibrillar material from nucleoli. Actinomycin D treatment, which inhibited virtually all RNA synthesis, caused varying types of segregation of nucleolar components. The morphology of nucleoli of KB and L cells and the reorganization of these nucleoli in response to drugs appear to be different from those of nucleoli of freshly initiated Chinese hamster and mouse cell lines.

Animals↗

PubMed1969

Sites of nucleolus production in cultured Chinese hamster cells.

Chinese hamster cell strains in the early passages in culture display wide variation in number of nucleolus-like bodies per cell, though such strains are characteristically euploid. A variety of criteria indicate that the nucleolus-like bodies are true nucleoli. Their Azure B- and fast green-staining properties indicate the presence of RNA and protein; they have typical nucleolar fine structure, including both fibrous and granular components; radioautography reveals that their patterns of uptake of uridine-(3)H into RNA are similar to those reported for nucleoli of other cell types; actinomycin D, at a level which selectively inhibits ribosomal RNA synthesis, greatly reduces their RNA synthesis and also causes segregation of fibrous and granular nucleolar components. Colchicine was used to experimentally fragment the nuclei of these cells into a number of separate karyomeres, each presumably containing some, or only one, of the chromosomes of the complement. Almost all the karyomeres contain nucleolus-like bodies which, by the same criteria applied to the multiple nucleolus-like bodies of uninuclear cells, appear to be true nucleoli. The nucleoli of individual karyomeres of the same cell often differ from each other in fine structure while the multiple nucleoli of a uninuclear cell generally resemble each other. The evidence presented in this study indicates that Chinese hamster cells contain many nucleolus-producing sites scattered through the genome.

Animals↗

PubMedDate not supplied

Acetylcodeine as a marker of illicit heroin abuse in oral fluid samples.

A method was developed using liquid chromatography linked to atmospheric pressure ionization-tandem mass spectrometry (LC-MS-MS) for the measurement of the opiates, morphine, codeine, 6-monoacetylmorphine (6-MAM), acetylcodeine (AC), and heroin in oral fluid collected from patients attending a substance abuse clinic. Of the 513 oral fluid samples tested, 297 showed detectable concentrations of 1 or more of the opiates and their respective percentage incidence being morphine (97%), codeine (82%), 6-MAM (77%), acetylcodeine (55%), and heroin (45%). A high percentage of these opiate-positive samples (40%) had detectable concentrations of all opiates tested. Significant correlations (p < 0.0001) were found between AC and 6-MAM (r = 0.95), heroin and 6-MAM (r = 0.81), and heroin and AC (r = 0.84). Although none of the subjects in this study were being treated with prescription heroin, nine showed detectable concentrations of heroin with no detectable AC. The mean concentration of heroin in these latter samples was very low compared with samples showing detectable AC (24 vs. 2571 microg/L). Several studies have reported the usefulness of measuring AC in urine for detection of illicit heroin abuse. This study demonstrates that the same marker can also be applied to oral fluid. The additional measurement of heroin in oral fluid is of limited use in monitoring subjects attending a substance abuse clinic.

Biomarkers↗