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Biomedical subjects

J R Coleman

Publications and source records attributed to J R Coleman.

At least 127 records · Page 7Linked to original sources
PubMed1968

Growing points of DNA in cultured mammalian cells.

A fraction of DNA, known to be replicating, was examined in the electron microscope. Characteristic branch points were identified as sites at which replication had been taking place. No localized strand separations, nor other structural alterations were discernible at these points.

Centrifugation, Density Gradient↗
PubMedDate not supplied

Resting and pure tone evoked metabolic responses in the inferior colliculus of young adult and senescent rats.

Metabolic responses from three sectors of the inferior colliculus (IC) divided according to frequency representation were examined bilaterally in young (YA) and aged adult (AA) rats using the 2-deoxyglucose method under quiescent or pure tone stimulus conditions. Resting IC metabolism in YA rats is characterized by elevated glucose uptake in the ventromedial (high frequency) relative to intermediate and dorsolateral sectors. AA resting incorporation is not reduced in any sector and is more uniform than YA uptake. Monaural high frequency stimulation (50 kHz) in YA animals evokes discrete contralateral banding along the ventromedial IC border, while stimulation in the optimal auditory sensitivity range of the rat at 8 kHz activates the intermediate sector of the contralateral IC. Although 50 kHz evoked ventromedial uptake is slightly reduced in AA rats contralaterally, the overall uptake within the three sectors does not differ significantly between ages under either of the monaural stimulus conditions; therefore senescent stability is exhibited. However, in AA rats the focus to 8 kHz stimulation has less clearly defined borders even though uptake within the intermediate sector is undiminished compared to YA animals, while 50 kHz elicited activity is typically reduced to a discontinuous band in the ventromedial sector of AA animals. These senescent changes may represent compensation in IC metabolism to changes in cochlear processing which are reflected in the activity of ascending auditory pathways.

Acoustic Stimulation↗
PubMedDate not supplied

Permeability measurement of macromolecules and assessment of mucosal antigen sampling using in vitro converted M cells.

INTRODUCTION: M cells are located in the epithelial layer covering the gut-associated lymphoid tissue and are responsible for delivery of macromolecules and microorganisms to the underlying lymphoid cells. It has been shown that the human colonic cell line Caco-2 can be converted to M cells in vitro following coculture with isolated lymphocytes from murine Peyer's patches. Studies were undertaken to evaluate and characterize the transepithelial transport of select macromolecules across these in vitro derived M cells. METHODS: Caco-2 cells were converted to M cells as reported previously. The morphology of Caco-2 cells and M cells was compared by transmission electron microscopy (TEM). The transport properties of macromolecules such as horseradish peroxidase, FITC-conjugated polystyrene beads, and radiolabeled dextrans were examined. The activation of murine antigen-specific T cells following transport of the antigen ovalbumin across the M-cell barrier was assessed by measuring cytokine production. RESULTS: M cells were shown to be irregular in shape and have fewer and shorter microvilli compared to the Caco-2 cell progenitors. These cells were still able to form tight junctions and monolayers on polycarbonate membranes. Time-course studies demonstrated that the transport of polystyrene beads and large-molecular-weight dextrans at physiological temperature across M-cell-containing monolayers was size dependent and more rapid than across Caco-2 cell monolayers. The transport of dextrans was also shown to be temperature and concentration dependent. Befitting the role of the M cell in mucosal defense, protein antigen could be delivered by these cells in order to be processed and presented to antigen-specific CD4+ T lymphocytes. DISCUSSION: The M-cell permeability model is a functional and practical system for evaluating the transport properties of macromolecules and assessing the potential for intestinal mucosal antigen sampling to elicit immunological responses.

Animals↗
PubMedDate not supplied

Integrated case management: the 21st century challenge for HMO case managers: Part I.

As HMOs approach the new millennium, their care and cost management strategies still will be under attack by policy-makers, legislative bodies, the media, American businesses, and the medical professions. The HMO industry will continue to be held accountable for the efficiency of its services, the quality of its care, and the performance and outcome measures that are the results of managing both the care and medical costs of its membership. This first of a two-part series put forward the concept of an integrated CM model to manage the total care of needs of HMO members at the turn of the century. This model consists of three care management approaches commonly used in mature HMOs: demand management, CM, and DM, as illustrated in Figure 1 and defined in Table 1. This article also described the new challenges facing HMOs, physicians, and nurse case managers and how they are navigating the difficult process of mapping demand management and CM approaches to the medical, social, and environmental needs of HMO members. With the costs of chronic conditions consuming 61% of the nation's annual health bill and increased numbers of the elderly joining HMOs, HMOs strongly need to implement DM approaches for economic survival reasons alone. Part two of this series will focus on the newest care management approach: disease state management.

Case Management↗