Biomedical subjects
J Keith
Publications and source records attributed to J Keith.
Testicular cancer: detection, prevention, and therapeutics.
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Comparisons of female and male early adolescent sex role attitude and behavior development.
This study contrasted female and male early adolescent sex role attitude and behavior development in an ecological context as defined by Bronfenbrenner. Data were the results of a state-wide survey of early adolescents and their parents. Hierarchical multiple regression was used to test both sex role attitude development and behavior development models. Only the models for attitude development were significant. The level of traditionalism of female sex role attitude development was significantly influenced by maternal employment, the level of traditionalism of the father's sex role attitudes in interaction with the amount of time he spent with his daughter, and chronological age. In contrast, the level of traditionalism of male sex role attitude development was significantly influenced by the level of traditionalism of the mother's sex role attitudes in interaction with the level of closeness to the mother that was reported by the son, and both mother's and father's perception of pubertal age. The implications of the findings for human development theory, early adolescence as a stage of development, and sex role theory and research are discussed.
Association of lipids with integral membrane surface proteins of Mycoplasma hyorhinis.
Triton X-114 (TX-114)-phase fractionation was used to identify and characterize integral membrane surface proteins of the wall-less procaryote Mycoplasma hyorhinis GDL. Phase fractionation of mycoplasmas followed by analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed selective partitioning of approximately 30 [35S]methionine-labeled intrinsic membrane proteins into the TX-114 phase. Similar analysis of [3H]palmitate-labeled cells showed that approximately 20 proteins of this organism were associated with lipid, all of which also efficiently partitioned as integral membrane components into the detergent phase. Immunoblotting and immunoprecipitation of TX-114-phase proteins from 125I-surface-labeled cells with four monoclonal antibodies to distinct surface epitopes of M. hyorhinis identified surface proteins p120, p70, p42, and p23 as intrinsic membrane components. Immunoprecipitation of [3H]palmitate-labeled TX-114-phase proteins further established that surface proteins p120, p70, and p23 (a molecule that mediates complement-dependent mycoplasmacidal monoclonal antibody activity) were among the lipid-associated proteins of this organism. Two of these proteins, p120 and p123, were acidic (pI less than or equal to 4.5), as shown by two-dimensional isoelectric focusing. This study established that M. hyorhinis contains an abundance of integral membrane proteins tightly associated with lipids and that many of these proteins are exposed at the external surface of the single limiting plasma membrane. Monoclonal antibodies are reported that will allow detailed analysis of the structure and processing of lipid-associated mycoplasma proteins.
After "the year of the nurse".
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Nucleotide sequence of the structural glycoprotein VP7 gene of Nebraska calf diarrhea virus rotavirus: comparison with homologous genes from four strains of human and animal rotaviruses.
A full-size cloned cDNA copy of the rotavirus gene encoding the structural neutralization glycoprotein (VP7) of Nebraska calf diarrhea virus (NCDV), a strain recently shown to be effective as a vaccine in children, has been sequenced. Comparison of the deduced amino acid sequence of NCDV (serotype 6) VP7 with that of four other rotavirus strains (human WA serotype 1, human HU-5 serotype 2, simian SA-11 serotype 3, and bovine UK serotype 6) indicates that the degree of amino acid homology among VP7 neutralization proteins of these serotypes ranges from 75 to 86%. Four hydrophilic regions at amino acid residues 174-183, 248-256, 287-294, and 310-317 exhibit significant homology and hence may represent common antigenic determinants, while one hydrophilic area at amino acid residues 83-102 exhibits sufficient divergence to suggest it may be involved in serotype specificity.
Presidential address: Conference '85.
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Asking patients to switch clinics.
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Membrane sterols and the development of the preimplantation mouse embryo.
The role of membrane sterols in the compaction and subsequent development of the preimplantation mouse embryo was studied by incubating embryos in 7-ketocholesterol and other oxygenated sterols. These sterols have been shown to inhibit sterol synthesis and deplete membranes of cholesterol in a variety of ther cell types. Compaction and subsequent blastocyst formation were normal when embryos were incubated in physiological sterols but were inhibited by oxygenated sterols to a degree which depended upon the concentration of sterol, duration of incubation and developmental age of the embryos. Precompaction 8-cell embryos were most susceptible to the action of these sterols and failed to compact (as assessed by cell flattening and increased intercellular adhesion) but continued to divide, whilst later stage embryos developed normally, 7-ketocholesterol had a specific effect on the ultrastructure of the smooth endoplasmic reticulum of treated embryos. The developmental and ultrastructural effects induced by the oxygenated sterols could be reversed or prevented by the use of products of the blocked reaction (i.e. mevalonate, desmosterol or cholesterol). These results substantiate the evidence that preimplantation mammalian embryos are capable of synthesizing membrane sterols from the 8-cell stage onwards and emphasize the importance of the sterol composition of membranes for normal cytokinesis and compaction of the mouse embryo.
Localization of N6-methyladenosine in the Rous sarcoma virus genome.
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[Evaluation of left ventricular function in coronary disease following aortocoronary bypass surgery].
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Effects of excess vitamin A on the cranial neural crest in the chick embryo.
Experiments on fertile hens' eggs have shown that an excess of vitamin A has a highly specific effect on the migration of cranial neural crest cells in the early stages of chick embryogenesis. Migration is disrupted and retarded. This is consistent with the causal mechanism proposed by Poswillo for the Treacher Collins syndrome.
Tobacco mosaic virus RNA carries 5'-terminal triphosphorylated guanosine blocked by 5'-linked 7-methylguanosine.
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Identification of the 5' end of Rous sarcoma virus RNA.
The 5'-terminal triphosphate of the 35S RNA isolated from Rous sarcoma virus is blocked by 7-methylguanosine in 5' linkage with the penultimate nucleoside which is methylated in the 2'-O-ribose position, a type of endgroup found in all animal mRNAs investigated during the past year. The specific nuclease-resistant terminal fragment of RSV RNA has the structure 7mG5'ppp5'GmpCp-. This finding supports the belief that RNA of Rous sarcoma virus represents a (+) strand messenger which may be directly translated upon infection.
Characterization of the end groups of RNA of Rous sarcoma virus.
The 3' terminus of the 30-35S RNA of Rous sarcoma virus is adenosine. Its amount indicates an average molecular weight for that RNA of about 3 x 10(6). The 5' terminus of 30-35S RNA of Rous sarcoma virus was not di- or triphosphorylated, whether isolated by the standard procedure or from virus collected within 3 min of its release from the cells.
Hyperthermia as a teratogenic agent.
The common cotton-eared marmoset, a nonhuman primate with a narrow zone of thermoneutrality, was used in an experiment to assess the effects of hyperthermia as a teratogenic agent. Mild heat stress conditions were used. The results of this preliminary study justify further investigation of the effect of hyperthermia on the primate embryo during morphogenesis.
Treatment of Wilms' tumor and factors affecting prognosis.
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Characteristic two-dimensional patterns of enzymatic digests of oncorna and other viral RNAs.
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