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Biomedical subjects

C Prince

Publications and source records attributed to C Prince.

26 records · Page 2Linked to original sources
PubMed1991

Lymphocyte and macrophage subpopulations in pelvic ileal pouches.

This study aimed to characterise the mucosal cellular infiltrate in ileal reservoirs with and without pouchitis (reservoir ileitis). Intraepithelial lymphocyte counts were performed in biopsy specimens obtained from ileal pouches and compared with counts in normal ileum and normal colon. T lymphocyte and macrophage subpopulations were characterised immunohistochemically in pouch biopsy specimens using a panel of monoclonal antibodies. Normal ileum was used as a control. Intraepithelial lymphocyte densities (expressed as intraepithelial lymphocyte/100 epithelial cells) in pouches with and without pouchitis were significantly less than in normal ileum, and approached counts found in normal colon. There was no significant increase in counts even in pouchitis. There were no significant differences in the helper/inducer to suppressor/cytotoxic T cell (CD4:CD8) ratios between normal ileum and pouches with or without pouchitis, either in the epithelium or in the lamina propria. The proportions of RFD9+ (epithelioid cells and tingible body macrophages) and 3G8+ (CD16) macrophages were significantly higher in pouchitis compared with pouches without pouchitis or normal ileum. There were no significant differences between the three groups in the proportions of cells positive for the other macrophage markers (CD68, RFD1-dendritic cells, and RFD7-mature macrophages). The significance of low intraepithelial lymphocyte counts in ileal pouches is unknown, but this may be an adaptive response to the new luminal environment. Since an increase in RFD9+ macrophages occurs in inflammatory bowel disease, but does not occur as a non-specific response to an acute infective process, their presence in pouchitis suggests that effector mechanisms similar to those triggering the original ulcerative colitis may be operating in pouchitis.

Adolescent↗
PubMed1989

Rippled-pattern trichomatricoma. Histological, immunohistochemical and ultrastructural studies of an immature hair matrix tumor.

A hair matrix tumor showing an unusual tumor cell arrangement was found at the base of a solitary trichoepithelioma. Coexisting with solid epithelial islands and immature hair follicle-like stroma resembling the Verocay bodies of neurilemmoma or "ripplemarks" on waves were found. In other areas myxomatous degeneration of the stroma changed the rippling into a cribriform pattern. In some parts of the tumor there was a dense melanin pigment associated with MEL5 stained melanocytes. S-100 and CD1 (OKT6) antigen stains demonstrated Langerhans cells scattered in the parenchyma and less frequently in the stroma. The majority of tumor cells were considered immature pilar cortical cells because of the following: 1. HKN-6 was strongly positive; 2. a large number of melanocytes were associated with tumor cells in some foci; 3. ultrastructurally immature tumor cells, which had electron-dense tonofilaments and many desmosomes, were transformed without production of trichohyalin granules into semikeratinized cells which showed nuclear degeneration and loss of electron density in tonofilaments. This tumor, however, has not attained the degree of differentiation observed in trichoblastoma (1) another example of an immature cortical cell tumor. Squamous eddy-like or horn pearl-like foci of incomplete keratinization and large keratin-filled cysts were also present within the immature parenchyma, indicating that some immature cells were differentiating toward non-cortical cells, as found in the outer sheath. We would like to designate this tumor "rippled pattern trichomatricoma", a new entity.

Adult↗
PubMed1985

Spatio-temporal integration in the substrate for self-stimulation of the prefrontal cortex.

The number of stimulation pulses required to maintain a half maximal rate of self-stimulation of the prefrontal cortex (PFC) was determined for various currents. Over a restricted range, the effects of decreasing the stimulation frequency could be compensated for by increasing the current. This finding cannot easily be reconciled with the hypothesis that the rewarding impact of PFC stimulation is unaffected by increments in current. The minimum current that would support self-stimulation of the PFC at high frequencies was larger than has been reported at medial forebrain bundle sites.

Animals↗
PubMed1984

Large melanoacanthomas: a report of five cases.

Five patients with melanoacanthoma are reported. The skin lesions consisted of a single, round plaque measuring several centimeters in diameter. Histologic findings were characterized by formation within an acanthotic epidermis, of many islands of small basaloid cells and highly dendritic melanocytes. Electron microscopic examination of one lesion revealed a disturbance of melanin transfer from the highly dendritic melanocytes to the neighboring keratinocytes.

Aged↗