Traction therapy in patients with herniated lumbar intervertebral discs.
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Humans↗
Biomedical subjects
L Walker
Publications and source records attributed to L Walker.
Management of heart disease in the elderly in the Plymouth health district.
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Aged↗
Flow cytometric staining of pancreatic endocrine cells.
Few distinct surface markers have been identified for endocrine cells, but antibodies directed against hormonal epitopes are widely available. In this study, human fetal pancreatic beta cells were identified on the flow cytometer by intracellular staining for insulin. A paraformaldehyde based permeabilization scheme was used which preserves surface staining and helps maintain cell integrity while allowing antibodies access to compartments within the cell interior. Cells were first stained for surface antigens, fixed in paraformaldehyde, and then permeabilized in phosphate buffered saline containing 0.2 percent Tween. Intracellular staining was accomplished using a fluorescein conjugated anti-insulin monoclonal antibody. In this manner, major histocompatibility complex Class II antigen expression was documented on beta cells exposed to interferon gamma. This study demonstrates the feasibility of using hormonal content to identify endocrine cells by flow cytometry while simultaneously staining for surface antigens.
Biomarkers↗
Human fetal islet response to interferon gamma.
Investigation was made of the ability of human fetal islets to express major histocompatibility complex class I and class II gene products after in vitro exposure to 1,000 U/ml Interferon Gamma (IFN) for 48 hours as well as the effect of such exposure on insulin secretion and autologous mixed islet lymphocyte response. Flow cytometry analysis revealed that the mean fluorescence activity of both HLA-ABC (class I) and HLA-DR (class II) was significantly (p < 0.01) increased vs the control after IFN incubation. (class I: Control = 125 +/- 35 SD, IFN = 995 +/- 418 S.D.; class II: Control = 70 +/- 30 SD, IFN = 300 +/- 74 S.D.). Cells containing surface expression of DR and intracellular insulin by flow cytometry following depletion of phagocytic cells were also quantified and increased from 0 to 0.67 percent following exposure to IFN. Autologous splenocytes responded to cells previously incubated with IFN with a three fold increase in 3H-thymidine uptake. Interferon gamma exposed, DR positive insulin containing cells contained one third the insulin of DR negative insulin containing cells (2.1 +/- 1.5 vs 6.6 +/- 3.4 microU/cell) but were nevertheless capable of stimulated insulin secretion. Thus, pharmacologic events leading to increased fetal pancreatic interferon concentrations initiate both immune and nonimmune processes that may predispose susceptible individuals to diabetes.
Cell Division↗