Protein-energy malnutrition induces immunosuppression that predisposes to sepsis, but the mechanisms are unclear. This study examines the role of the macrophage in host defense in the malnourished ...state. Swiss-Webster mice (N = 300) were randomly allocated to control (24% casein) or low-protein (2.5% casein) diets for 8 weeks. We studied the ability of two populations of macrophages, peritoneal macrophages, and Kupffer cells to produce superoxide anion after in vivo administration of endotoxin or mycobacterium (bacille Calmette-Guérin). Phorbol diester and Candida albicans were used as stimuli. In another group of mice, we evaluated the ability of interferon gamma to up-regulate superoxide anion release and Candida phagocytosis and killing. Mice under protein-energy malnutrition demonstrated decreased mean body weights, serum protein levels, and cell yields. Superoxide anion production in resident and activated (lipopolysaccharide, interferon gamma, bacille Calmette-Guérin infection) peritoneal macrophages was significantly reduced in the malnourished group. Candida phagocytosis and killing were also both depressed in malnourished mice. Kupffer cells failed to generate superoxide anion in all groups. We conclude that severe protein-energy malnutrition significantly impairs macrophage function, which could diminish response to acute and chronic septic challenges. Interferon gamma up regulated peritoneal macrophage and Kupffer cell microbicidal function, which suggests a therapeutic role for this lymphokine in the malnourished septic host.
Examination of the lipids of three species of nonphotosynthetic bacteria with extensive internal membranes revealed phosphatidyl choline (lecithin) in two species. In one of these there was an ...unusual accumulation of phosphatidyl N-dimethylethanolamine. (The relation between lecithin and membrane elaboration in micro-organisms is discussed.)
Electron microscope autoradiographs were prepared from diabetic rat pancreatic acini that had been incubated with 125I-insulin. Distribution histograms of the distance of the 125I-insulin silver ...grains from the nearest plasma membrane were prepared and compared with a histogram of an 125I line source. After 3 min of incubation, insulin was located predominately on the plasma membrane, but even at this early time 15% of the grains had an intracellular location. After 30 min of incubation, there was a decrease in grains on the plasma membrane and an increase (to 45%) in grains localized in the cell. At both times of incubation, a comparison of the distribution of the insulin grains overlying subcellular organelles to a theoretical random grain distribution pattern indicated that the intracellular distribution of insulin grains was nonrandom. At 3 min, there was a relative concentration of grains over the plasma membrane and vesicles with an average diameter of 100 nm. At 30 min, there was a concentration of grains over the plasma membrane, 100-nm vesicle, and Golgi. These studies suggest that 125I-insulin is internalized into pancreatic acinar cells in a time-dependent manner and then is nonrandomly distributed inside the cell.
Insulin Activity: The Solid Matrix Butcher, R. W.; Crofford, Oscar B.; Gammeltoff, Steen ...
Science (American Association for the Advancement of Science),
10/1973, Volume:
182, Issue:
4110
Journal Article
Letter: Insulin activity: the solid matrix Butcher, R W; Crofford, O B; Gammeltoff, S ...
Science (American Association for the Advancement of Science),
1973-Oct-26, 19731026, Volume:
182, Issue:
4110
Journal Article
