Biomedical subjects

K Rock

Publications and source records attributed to K Rock.

7 recordsLinked to original sources

PubMed1999

Distinct proteolytic processes generate the C and N termini of MHC class I-binding peptides.

Most of the MHC class I peptides presented to the immune system are generated during the course of protein breakdown by the proteasome. However, the precise role of the proteasome, e.g., whether this particle or some other protease generates the carboxyl (C) and amino (N) termini of the presented 8- to 10-residue peptides, is not clear. Here, we show that presentation on Db of ASNENMETM, a peptide from influenza nucleoprotein, and on Kb of FAPGNYPAL, a peptide from Sendai virus nucleoprotein, was blocked by the proteasome inhibitor, lactacystin. Using plasmid minigene constructs encoding oligopeptides of various lengths, we found that presentation of ASNENMETM from C-terminally extended peptides that contain this antigenic peptide plus three or five additional amino acids and presentation of FAPGNYPAL from a peptide containing FAPGNYPAL plus one additional C-terminal residue required the proteasome. In contrast, the proteasome inhibitor did not reduce presentation of cytosolically expressed ASNENMETM or FAPGNYPAL or N-terminally extended versions of these peptides, suggesting involvement of aminopeptidase(s) in trimming these N-extended variants. Accordingly, when the N termini of these 3N-extended peptides were blocked by acetylation, they were resistant to hydrolysis by cellular aminopeptidases and pure leucine aminopeptidase. Moreover, if introduced into the cytosol, Ag presentation of these peptides occurred to a much lesser extent than from their nonacetylated counterparts. Thus, the proteasome is essential for the generation of ASNENMETM and FAPGNYPAL peptides from the full-length nucleoproteins. Although it generates the C termini of these presented peptides, distinct aminopeptidase(s) can trim the N termini of these presented peptides to their proper size.

Aminopeptidases↗

PubMed1996

The use of the edema bar for the treatment of burn patients.

The edema bar is a new device that therapists can add to their repertoire of treatment approaches for burn patients. This article looks at the challenges therapists encounter while working with burn patients and describes the edema bar's design, its application to the burn rehabilitation process, and the multidisciplinary approach to its use.

Burns↗

PubMed1992

Effects of time of day and appropriateness on food intake and hedonic ratings at morning and midday.

In societies such as the U.S.A. many foods are considered appropriate or inappropriate for particular meals. Although some previous work has indicated that hedonic ratings reflect these cultural patterns, little is known about the impact of time of day and "appropriateness" in particular on food acceptance and intake. The purpose of the present study was to explore the role of appropriateness on consumption and hedonic ratings of breakfast and non-breakfast foods. Experiment 1 examined these factors in the context of four meals in which the type of menu (breakfast or lunch) was factorially combined with time of day (breakfast time or lunchtime). Experiment 2 examined hedonic ratings obtained in the morning and afternoon using samples of the same foods and rating methods used in Experiment 1. Experiment 3 replicated Experiment 2 but employed the rating methods used in Birch et al. (1984). Results from the three experiments indicated that the appropriateness or inappropriateness of when foods were served had no effect upon hedonic ratings and no clear impact on food intake. Postmeal hunger ratings in Experiment 1, however, provided some support for the salience of appropriateness. These results suggest that appropriateness may be more relevant to food selection than to consumption or palatability per se.

Adult↗

PubMed1989

Motivating middle managers. How to develop their mission potential.

Today's unstable healthcare environment is prompting not-for-profit hospitals to explore ways to preserve a fading altruistic posture. Holy Cross Hospital, Salt Lake City, sees middle management as a key to preserving a mission-oriented commitment to the delivery of healthcare. It is tapping the potential of its middle managers through a specialized management development program linked to mission objectives that attempts to assess and enhance individual abilities. The hospital formed a management development committee to identify several managerial characteristics that could have the greatest positive impact on preserving the hospital's mission objectives. The committee identified six major categories for focus: mission and philosophy; leadership style and influence; staffing, coaching, and developing employees; implementation functions; decision-making functions; and quality assurance issues. The hospital developed a self-assessment questionnaire for middle managers. As a self-evaluation tool, the questionnaire may not accurately represent each manager's specific level of knowledge, but it shows each manager's perceived needs and provides a basis for the development of instructional resources. It has also been useful in raising managers' consciousness of their performance.

Hospital Administrators↗

PubMed1978

The role of H-2 linked genes in helper T-cell function. II. Isolation on antigen-pulsed macrophages of two separate populations of F1 helper T cells each specific for antigen and one set of parental H-2 products.

A method was established for isolating antigen-specific murine helper T cells by selective binding to antigen-pulsed macrophage (Mphi) monolayers. Sheep erythrocyte (SRBC)-primed T cells, which remained strongly adherent to SRBC-pulsed syngeneic Mphi after 20 h in culture, were markedly enriched for helper activity when tested in the in vitro antitrinitrophenol (TNP) response to TNP-SRBC. Successful binding and enrichment occurred only if the Mphi were pulsed with the specific antigen to which the T-cell donors had been primed. The genetic control governing helper function in this system was then examined by using primed F1 T cells isolated on Mphi monolayers from congenic strains bearing parental H-2 haplotypes. SRBC-primed BDF1 (H-2b X H-2d) T cells, which bound to SRBC-pulsed H-2d Mphi, subsequently functioned as helper cells in cultures containing H-2d B cells and Mphi, but not in those containing H-2b B cells and Mphi. They remained unable to collaborate with B cells of the H-2B haplotype even in the presence of additional H-2d Mphi, indicating that H-2 restriction occurs at least at the level of the B cell. Similary, primed BDF1 T cells isolated on H-2b Mphi cooperated preferentially with H-2b B cells and Mphi. In both cases, the haplotype preference of the T cell was not due to alloreactive suppressor activity. These results suggest that primed F1 mice contain individual populations of helper T cells, each of which recognize antigen in association with a parental H-2 gene product(s) expressed during both Mphi-T cell and T cell-B cell interactions.

Animals↗

PubMed1977

Studies on cell recognition in the developing brain.

Several lines of evidence demonstrate cell-cell receptors on the surface of developing brain cells. Plasma membrane vesicles with regional and temporal binding specificities can be prepared. Active factors that block cell aggregation can be extracted from these membranes and partially purified. Quantitative studies of cell-cell adhesion demonstrate a gradient of adhesive specificity along the dorsoventral axis of the developing retina.

Animals↗

PubMed1976

A gradient of adhesive specificity in developing avian retina.

Cell-cell adhesion was examined in the developing chick neural retina. A dorsoventral gradient of adhesive specificity in dissociated cells was detected which exhibits a complementarity such that the highest cell-cell affinities are exhibited between cells derived from the extremes of the gradient. If a nasotemporal gradient exists it must exhibit significantly lower cell-cell affinity. The relevance of these findings to pattern formation in the nervous system is discussed.

Age Factors↗