Biomedical subjects

K Rock

Publications and source records attributed to K Rock.

4 recordsLinked to original sources

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↗

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↗