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D H Hayes

Publications and source records attributed to D H Hayes.

60 records · Page 4Linked to original sources
PubMed1966

The effect of high ionic strength on the sedimentation properties of the biologically active component of bacterial ribonucleic acid.

1. The sedimentation properties of the fraction of bacterial RNA which stimulates the incorporation of amino acids into acid-insoluble material in vitro depend on the ionic strength of the sedimentation medium. 2. The different distributions of stimulatory activity found in centrifuged linear sucrose gradients loaded with bacterial RNA and containing 0.1m- or 0.6m-sodium chloride resemble closely the different sedimentation profiles of rapidly labelled RNA observed under the same conditions. 3. These findings agree with those of previous work of a similar nature (Willson & Gros, 1964) and demonstrate that the component of bacterial RNA preparations which stimulates the incorporation of amino acids into acid-insoluble peptides in vitro is contained in their rapidly labelled fraction.

Carbon Isotopes↗
PubMedDate not supplied

Partial deproteinization of ribosomal subunits by treatment with high concentrations of sodium chloride: physical and chemical characterization of protein depleted particles.

Sedimentation of E. coli ribosomal subunits through sucrose gradients containing high concentrations of NaCl (0.1 - 1.0 M) brings about removal of a specific fraction of their proteins. The alterations in the structural properties of the subunits caused by dissociation of these proteins are studied. They appear to be, at least partly the result of removal of constraints on RNA conformation imposed by the released proteins.

Centrifugation, Density Gradient↗
PubMedDate not supplied

Effects of partial deproteinization on the functional properties of 50S ribosomal subunits of E. coli.

Sedimentation of E. coli 50S ribosomal subunits through sucrose gradients containing 10 mM Mg2+ and high concentrations of NaCl (0.1-1.0 M) leads to removal of proteins L16 and L25. Analyses of the structural and functional properties of the protein depleted particles shows that removal of L16 and L25 from the 50S subunit causes loss of its ability to bind tRNA, to associate with the 30S subunit and to catalyze peptide bond formation. Reassociation of both L16 and L25 with core particles lacking these proteins is necessary for recovery of peptidyl transferase activity.

Centrifugation, Density Gradient↗
PubMedDate not supplied

Biopsy technique has no impact on local recurrence after breast-conserving therapy.

Image-guided core needle breast biopsy (IGCNBB) is an incisional biopsy technique that has been associated with tumor cell displacement. Theoretically tumor cell displacement may affect local recurrence rates in patients treated with breast-conserving therapy (BCT). We performed a study to determine if the biopsy method impacted local control rates following BCT. Patients with nonpalpable breast cancer (invasive and intraductal) diagnosed at our institution and treated with BCT between July 1993 and July 1996 were selected to provide a follow-up period in which the majority of local recurrences should be detected. Patients were divided into two groups based on their method of diagnosis. Group I patients were diagnosed by IGCNBB and group II patients were diagnosed by wire localized excisional breast biopsy (WLEBB). Factors potentially affecting local recurrence rates were retrospectively reviewed. Two hundred eleven patients were treated with BCT, 132 were diagnosed by IGCNBB and 79 by WLEBB. The two patient groups were similar when compared for prognostic factors and treatment. All patients' BCT included histologically negative margins. There were 4 (3.0%) local recurrences in Group I at a median follow-up of 44.4 months and 2 (2.5%) local recurrences in group II at a median follow-up of 50.1 months. This difference was not significant. Breast cancer patients diagnosed by IGCNBB can be treated by BCT with acceptable local control rates. Additional surveillance of our institutional experience and others' is mandatory to validate IGCNBB as the preferred biopsy method for nonpalpable mammographic abnormalities.

Age Distribution↗