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Biomedical subjects

S G Phillips

Publications and source records attributed to S G Phillips.

At least 19 recordsLinked to original sources
PubMed1998

Prevalence of articles with honorary authors and ghost authors in peer-reviewed medical journals.

CONTEXT: Authorship in biomedical publications establishes accountability, responsibility, and credit. Misappropriation of authorship undermines the integrity of the authorship system, but accurate data on its prevalence are limited. OBJECTIVES: To determine the prevalence of articles with honorary authors (named authors who have not met authorship criteria) and ghost authors (individuals not named as authors but who contributed substantially to the work) in peer-reviewed medical journals and to identify journal characteristics and article types associated with such authorship misappropriation. DESIGN: Mailed, self-administered, confidential survey. PARTICIPANTS: A total of 809 corresponding authors (1179 surveyed, 69% response rate) of articles published in 1996 in 3 peer-reviewed, large-circulation general medical journals (Annals of Internal Medicine, JAMA, and The New England Journal of Medicine) and 3 peer-reviewed, smaller-circulation journals that publish supplements (American Journal of Cardiology, American Journal of Medicine, and American Journal of Obstetrics and Gynecology). MAIN OUTCOME MEASURES: Prevalence of articles with honorary authors and ghost authors, as reported by corresponding authors. RESULTS: Of the 809 articles, 492 were original research reports, 240 were reviews and articles not reporting original data, and 77 were editorials. A total of 156 articles (1 9%) had evidence of honorary authors (range, 11%-25% among journals); 93 articles (11%) had evidence of ghost authors (range, 7%-16% among journals); and 13 articles (2%) had evidence of both. The prevalence of articles with honorary authors was greater among review articles than research articles (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.2-2.6) but did not differ significantly between large-circulation and smaller-circulation journals (OR, 1.4; 95% CI, 0.96-2.03). Compared with similar-type articles in large-circulation journals, articles with ghost authors in smaller-circulation journals were more likely to be reviews (OR, 4.2; 95% CI, 1.5-13.5) and less likely to be research articles (OR, 0.49; 95% CI, 0.27-0.88). CONCLUSION: A substantial proportion of articles in peer-reviewed medical journals demonstrate evidence of honorary authors or ghost authors.

Authorship↗
PubMed1986

Congenital conductive hearing loss in Apert syndrome.

Acrocephalosyndactyly (Apert syndrome) is a rare craniosynostotic syndrome characterized by acrocephaly, syndactyly of the hands and feet, and--occasionally--conductive hearing loss. We report three cases of conductive hearing loss in Apert syndrome. One patient was found to have bilateral stapes fixation. His daughter (the second case) had chronic bilateral otitis media with effusion. The third case involved a fixed incus and hypomobile stapes. The management of these patients and a review of the literature are presented.

Acrocephalosyndactylia↗
PubMed1982

Binding of epithelial cells to lectin-coated surfaces.

Epithelial cells may relate to their basement membrane substrates via lectin-like interactions. In a model system for study of this type of interaction, lectin-coated bacteriological plastic petri dishes were presented as substrates for epithelial cell adhesion. Of 21 lectins tested by mixed agglutination against two epithelial cell types, Madin-Darby canine kidney (MDCK), and human embryonic kidney cells (HEK), nine gave less than 5% rosettes and 12 gave 5 to 50% rosettes. Wheat germ agglutinin (WGA) and Geodia cydonium lectin gave the highest percentage of rosettes. Wheat germ agglutinin was readily adsorbed to plastic surfaces and maintained specificity in binding interactions. Both MDCK and HEK cells attached as well to WGA coated petri dishes as to conventional tissue culture dishes. Furthermore, both spread over the lectin-coated surfaces. The MDCK cells grew to confluence and could be subcultured and maintained indefinitely on such surfaces, although WGA in solution was toxic to the cells in concentrations as low as 0.1 to 1.0 microgram/ml. Cell attachment to WGA coated dishes was blocked by cycloheximide only if the cells had been preincubated with the inhibitor for several hours. Cell attachment was not inhibited by pretreatment of cells with neuraminidase. Precoating cells with WGA blocked binding to both WGA-coated surfaces and untreated tissue culture dishes. Cells attached to WGA-coated dishes could not be readily dislodged by trypsin-EDTA for the first 2 h after subculture. By 4 h, attachment was again trypsin sensitive, suggesting that the cells synthesized a trypsin-sensitive material that was laid down between the cell surface and the WGA-coated dish. Regeneration of trypsin sensitivity was not blocked by cycloheximide.

Animals↗
PubMed1981

A mitogenic lactose-binding lectin from the sponge Geodia cydonium.

Two lectins with affinity for hog A + H blood group substance were extracted from the Mediterranean sponge Geodia cydonium. One, termed Geodia lectin I, was purified to near homogeneity by lactose elution from a column of hog A + H coupled to Sepharose 4B. Geodia lectin I was a glycoprotein (carbohydrate content about 14%) with m.w. of about 60,000 and an isoelectric point of pH 4.4. Subunits of about 15,000 daltons were linked by disulfide bonds. The lectin precipitated with various snail galactans composed entirely of DGal and LGal, to a slight degree with guaran, which has DGal alpha 1 leads to 6 in a terminal nonreducing position, and with blood group substances. Of 42 sugars tested, only lactose, dGal beta 1 leads to 4 DGlcNAc, DGal beta 1 leads to 3DGlcNAc, DGalNAc, inhibited precipitation. In view of the relatively high concentration of those disaccharides that inhibited relative to other lectins, the specificity of interaction is thought to be via beta-linked DGal residues that are part of a more complex combining site. Geodia lectin I was mitogenic for human peripheral blood lymphocytes with an optimal concentration of about 5.6 micrograms/ml if serum was omitted for the first 24 hr of culture to allow "triggering." Fetal calf serum apparently contained a high concentration of substances that inhibited mitogenicity and hemagglutination by Geodia lectin I, presumably by specifically interacting with the binding site.

Amino Acids↗
PubMed1978

Human semen as a source of epithelial cells for culture.

When washed cells from human semen samples were plated out, epithelial cultures were obtained. The human ejaculates used as starting material contained, in addition to spermatazoa, 10(3) to 10(7) cells of other types, including granulocytes, macrophages, lymphocytes, spermatocytes and epithelial cells. Although no fractionation of cell types was attempted, semen samples yielded epithelial cultures uncontaminated by fibroblasts. The cultured cells appeared characteristically epithelial with a polygonal shape, interdigitating cell membranes, and desmosomes. ABH blood-group antigenic determinants of the donor were expressed with variable frequency as a surface antigen on these cells. About half the trials gave some cell attachment. Most cultures remained as small, tight colonies, but a few reached confluency in about 5 weeks and could be subcultured successfully. Cell proliferation, as monitored by (3H) thymidine incorporation into nuclear macromolecules, ceased in less than 2 months.

Antigens, Surface↗
PubMed1976

Dependence of centriole formation on protein synthesis.

Centriole formation was studied after inhibition of protein synthesis for various portions of the cell cycle. Synchronous populations of mitotic L929 (mouse) cells were plated into petri dishes and the course of procentriole formation was monitored by electron microscope analysis. The frequency with which procentrioles were seen in association with mature centrioles normally increased steadily in the interval from 4 to 12 h after mitosis. The formation of procentrioles was abruptly inhibited by the addition of cycloheximide at any time from mitosis until 12 h postmitosis (S phase). This suggested that the formation of procentrioles was dependent upon protein synthesis immediately before their appearance. Prophase-accociated elongation of procentrioles appeared to occur normally in cells treated with cycloheximide for up to 4 h before prophase, though the mitotic index in treated cultures decreased somewhat. Thus, protein synthesis did not appear to be essential for procentriolar elongation to the mature length.

Cell Division↗
PubMed1976

A galactose-inhibitable mitogen for human lymphocytes from the sponge axinella polypoides.

Of two galactose-binding hemagglutinins isolated from the sponge Axinella polypoides, axinella I was strongly mitogenic for human peripheral blood lymphocytes, and axinella II was not. Purified T cells responded strongly and B cells weakly to axinella I. Mitogenic response, as monitored by rate of 3H-thymidine incorporation on the third day of culture, was specifically inhibited by Dgalactose, Dfucose, raffinose, or 2-deoxy-D-galactose added within 5 hr of the mitogen. Mitogenic response was correlated with degree of lymphocyte agglutination. The effectiveness of a given sugar in inhibiting mitogenic response to axinella I paralleled its potency in inhibiting precipitation of lectin by blood group substances. If an inhibitory concentration of Dgalactose was add 24 to 40 hr after mitogenic activation, rate of 3H-thymadine uptake at 72 hr was two to twenty times above the rate induced in cultures to which no galactose was added. Dgalactose at a subinhibitory concentration (10mug/ml) enhanced 3H-thymidine incorportion incorporation induced by phytohemagglutinin or Con A, an effect reversible by Dgalactose. These findings suggest that axinella I has tow antagonistic effects on human lymphocytes: a) mitogenic activation and b) depressive activity resulting from depletion of essential galactose moieties.

B-Lymphocytes↗
PubMed1973

Independence of centriole formation and DNA synthesis.

The temporal relationship between cell cycle events and centriole duplication was investigated electron microscopically in L cells synchronized by mechanically selecting mitotic cells. The two mature centrioles which each cell received at telophase migrated together from the side of the telophase nucleus distal to the stem body around to a region of the cytoplasm near the stem body and then into a groovelike indention in the early G(1) nucleus, where they were found throughout interphase. Procentrioles appeared in association with each mature centriole at times varying from 4 to 12 h after mitosis. Since S phase was found to begin on the average about 9 h after mitotic selection, it appeared that cells generated procentrioles late in G(1) or early in S. During prophase, the two centriolar duplexes migrated to opposite sides of the nucleus and the daughter centrioles elongated to the mature length. To ascertain whether any aspect of centriolar duplication was contingent upon nuclear DNA synthesis, arabinosyl cytosine was added to mitotic cells at a concentration which inhibited cellular DNA synthesis by more than 99%. Though cells were thus prevented from entering S phase, the course of procentriole formation was not detectibly affected. However, cells were inhibited from proceeding to the next mitosis, and the centriolar elongation and migration normally associated with prophase did not occur.

Cell Division↗
PubMed1973

Repopulation of postmitotic nucleoli by preformed RNA. II. Ultrastructure.

The reconstruction of the nucleolus after mitosis was analyzed by electron microscopy in cultured mammalian (L929) cells in which nucleolar RNA synthesis was inhibited for a 3 h period either after or before mitosis. When synchronized mitotic cells were plated into a concentration of actinomycin D sufficient to block nucleolar RNA synthesis preferentially, nucleoli were formed at telophase as usual. 3 h after mitosis, these nucleoli had fibrillar and particulate components and possessed the segregated appearance characteristic of nucleoli of actinomycin D-treated cells. Cells in which actinomycin D was present for the last 3 h preceding mitosis did not form nucleoli by 3 h after mitosis though small fibrillar prenucleolar bodies were detectable at this time. These bodies subsequently grew in size and eventually acquired a particulate component. It took about a full cell cycle before nucleoli of these cells were completely normal in appearance. Thus, nucleolar RNA synthesis after mitosis is not necessary for organization of nucleoli after mitosis. However, inhibition of nucleolar RNA synthesis before mitosis renders the cell incapable of forming nucleoli immediately after mitosis. If cells are permitted to resume RNA synthesis after mitosis, they eventually regain nucleoli of normal morphology.

Cell Nucleolus↗
PubMed1972

Repopulation of the postmitotic nucleolus by preformed RNA.

This study is concerned with the fate of the nucleolar contents, particularly nucleolar RNA, during mitosis Mitotic cells harvested from monolayer cultures of Chinese hamster embryonal cells, KB6 (human) cells, or L929 (mouse) cells were allowed to proceed into interphase in the presence or absence (control) of 0.04-0 08 microg/ml of actinomycin D, a concentration which preferentially inhibits nucleolar (ribosomal) RNA synthesis 3 hr after mitosis, control cells had large, irregularly shaped nucleoli which stained intensely for RNA with azure B and for protein with fast green. In cells which had returned to interphase in the presence of actinomycin D, nucleoli were segregated into two components easily resolvable in the light microscope, and one of these components stained intensely for RNA with azure B. Both nucleolar components stained for protein with fast green In parallel experiments, cultures were incubated with 0.04-0 08 microg/ml actinomycin D for 3 hr before harvesting of mitotic cells, then mitotic cells were washed and allowed to return to interphase in the absence of actinomycin D. 3 hr after mitosis, nuclei of such cells were devoid of large RNA-containing structures, though small, refractile nucleolus-like bodies were observed by phase-contrast microscopy or in material stained for total protein. These experiments indicate that nucleolar RNA made several hours before mitosis persists in the mitotic cell and repopulates nucleoli when they reform after mitosis

Animals↗