Search PubMed⌕ Search

Biomedical subjects

J Pitts

Publications and source records attributed to J Pitts.

52 records · Page 3Linked to original sources
PubMed1987

Patterns of junctional communication in animal tissues.

Gap junctions provide pathways for direct communication between cells in almost all animal tissues. The junctional channels are freely permeable to small ions and molecules but not to macromolecules. A coupled cell population is as a consequence a partial syncytium, within which metabolites, cofactors, small control molecules and inorganic ions can all diffuse freely through the combined cytoplasmic compartment, while intracellular macromolecules remain relatively fixed in space, in the cells where they are synthesized. Little is known about the extent and distribution of these communication compartments in tissues. To further understand their significance, we have mapped the patterns of junctional communication in skin by intracellular injection of the tracer dye Lucifer Yellow. Cells in the dermal layer are widely coupled, with dye spreading through hundreds of cells in a few minutes. Dye spread in the epidermis is much more restricted, passing in the same time into only a few cells. Dermal-epidermal coupling is not normally detected but is occasionally seen in new-born mouse skin when hair follicles are starting to invaginate. Dermal cells are coupled to a band of follicular cells near the base of mature hair follicles, whereas sebaceous glands appear to be coupled units, isolated from surrounding cells.

Animals↗
PubMed1985

The conformation of insulin-like growth factors: relationships with insulins.

The insulin-like growth factors and hystricomorph insulins have been modelled by interactive computer graphics on the assumption that their sequence homology to insulin implies that they will have a similar tertiary structure. These studies suggest that, although the insulin-related molecules can adopt the insulin fold, they are unlikely to form hexamers and if they form dimers they will be of reduced stability. The non-suppressibility of insulin-like growth factors by anti-insulin antibodies is explained in terms of differences of surface residues in the region A8-A10 and B1-B5. Receptor affinity of insulins and insulin-like growth factors for insulin receptors is explicable in terms of a receptor-binding site in the vicinity of B25 Phe on the insulin surface. An equivalent region around B25 Tyr of insulin-like growth factors may be responsible for their binding to type 1 receptors, although binding type 2 receptors must involve a different surface region not shared by insulin.

Amino Acid Sequence↗
PubMedDate not supplied

The use of nurse practitioners in pediatric institutions.

INTRODUCTION: Across the United States nurse practitioners (NPs) are used in widely different ways even when they are employed in similar settings. The purpose of this survey was to describe the use of NPs in pediatric hospitals. METHOD: A survey was conducted of the chief nurse officers in pediatric hospitals associated with the National Association of Children's Hospitals and Related Institutions. Questions were asked about hiring practices, qualifications, specialties of the NPs employed, practice arrangements, patient volume, and reimbursement. The 22-question survey instrument was developed by the authors. The response rate for the survey was 86% (42 of 49 surveys were returned). RESULTS: The results identified that most of the hospitals surveyed reported less than 50,000 clinic visits per year, NPs were used most often in the specialties of neonatology, hematology/oncology, and primary care, more than one half of the surveyed hospitals required a masters degree for NPs, only 22% of NPs had prescriptive authority, and NPs practiced in 88% of surveyed pediatric hospitals. DISCUSSION: Institutional and statutory boundaries continued to limit the practice of the NP. Inconsistent education and practice standards and a lack of understanding and acceptance of the role also inhibit NPs from being used to the fullest potential in pediatric hospitals.

Hospitals, Pediatric↗
PubMedDate not supplied

Relationship between intercellular communication and adriamycin resistance in non-small cell lung cancer.

The adriamycin chemosensitivity and extent of gap junctional intercellular communication were assessed in a panel of seven human non-small cell lung cancer (NSCLC) cell lines. Communication was assessed by autoradiographic detection of transfer of 3H uridine nucleotides between coupled cells. The strength of coupling varied widely between the cell lines and they could be separated into 3 groups: those which exhibited strong coupling, L-DAN and A549; those which exhibited weak coupling, SK-MES-1, Calu-3 and NCI-H125; and an intermediate group, WIL and NCI-H23. Adriamycin chemosensitivity was assessed by both clonogenic and MTT assays. The range of IC50 values as measured by either assay was extremely narrow, with no important differences between the lines. Thus, despite the wide spectrum of intercellular communication observed in these lines, this did not correlate with their adriamycin resistance.

Autoradiography↗