Rapid redistribution of clathrin onto macrophage plasma membranes in response to Fc receptor-ligand interaction during frustrated phagocytosis.

We have observed increases in assembled clathrin on the plasma membrane during "frustrated phagocytosis," the spreading of macrophages on immobilized immune complexes. Resident macrophages freshly harvested from the peritoneal cavity of mice and attached to bovine serum albumin (BSA)-anti-BSA-coated surfaces at 4 degrees C had almost no clathrin basketworks on their adherent plasma membrane (less than 0.01 coated patch/micron 2), as observed by immunofluorescence, immunoperoxidase, and platinum-carbon replica techniques, although abundant assembled clathrin was observed in the perinuclear Golgi region. When the cells were warmed to 37 degrees C they started to spread by 4 min and reached their maximum extent by 20 min. Spreading preceded clathrin assembly at the plasma membrane. Clathrin-coated patches were first observed on the adherent plasma membrane at 6 min. Between 12 and 20 min assembled clathrin coats appeared on both adherent and nonadherent plasma membranes with a concomitant decrease in identifiable clathrin in the perinuclear region. A new steady state emerged by 2 h, as perinuclear clathrin began to reappear. At 20 min at 37 degrees C the adherent plasma membranes of macrophages spreading on BSA alone had 0.9 coated patch/micron 2, whereas in cells spread on immune complex-coated surfaces, the clathrin patches increased, dependent on ligand concentration, to a maximum of 2.1 coated patches/micron 2. Because frustrated phagocytosis of immune complex-coated surfaces at 37 degrees C increased the area of adherent plasma membrane, the total area coated by clathrin basket-works increased 5-fold (28 micron 2/cell) as compared with cells plated on BSA alone (5.6 micron 2/cell) and 200-fold as compared with cells adhering to immune complexes at 4 degrees C. We then determined that macrophages cultured on BSA-coated coverslips for 24 h already have abundant surface clathrin. When immune complexes were formed by the addition of anti-BSA IgG to already spread macrophages cultured on BSA-coated coverslips for 24 h, clathrin assembled at the sites of ligand-receptor interaction even at 4 degrees C, before spreading, and a 2.6-fold increase in assembled clathrin was observed on the adherent plasma membrane of cells on immune complexes as compared with cells on BSA alone. Clathrin was reversibly redistributed to the Golgi region, returning to the steady state by 2 h.(ABSTRACT TRUNCATED AT 400 WORDS

A platelet alpha-granule membrane protein (GMP-140) is expressed on the plasma membrane after activation.

We have previously characterized a monoclonal antibody, S12, that binds only to activated platelets (McEver, R.P., and M.N. Martin, 1984, J. Biol. Chem., 259:9799-9804). It identifies a platelet membrane protein of Mr 140,000, which we have designated as GMP-140. Using immunocytochemical techniques we have now localized this protein in unstimulated and thrombin-stimulated platelets. Polyclonal antibodies to purified GMP-140 were used to enhance the sensitivity of detection. Nonpermeabilized, unstimulated platelets, incubated with anti-GMP-140 antibodies, and then with IgG-gold probes, showed very little label for GMP-140 along their plasma membranes. In contrast, thrombin-stimulated platelets exhibited at least a 50-fold increase in the amount of label along the plasma membrane. On frozen thin sections of unstimulated platelets we observed immunogold label along the alpha-granule membranes. We also employed the more sensitive technique of permeabilizing with saponin unstimulated platelets in suspension, and then incubating the cells with polyclonal anti-GMP-140 antibodies and Fab-peroxidase conjugate. Alpha-granule membranes showed heavy reaction product, but no other intracellular organelles were specifically labeled. These results demonstrate that GMP-140 is an alpha-granule membrane protein that is expressed on the platelet plasma membrane during degranulation

Oral health knowledge and behavior among male health sciences college students in Kuwait

BACKGROUND: Health auxiliary personnel have an important role in oral health promotion when they graduate and start working in the health care system. This study aims to find out oral health knowledge and oral health behavior of male Health Sciences College students. METHODS: A questionnaire was distributed to all students at the male Health Sciences College in Kuwait (N = 153) during the academic year 2001/2002. The students filled the anonymous questionnaire in the class after the lecture. The response rate was 84% (n = 128). The questions consisted information on the general background, oral health behavior and oral health knowledge. RESULTS: Oral health knowledge seemed to be limited and very few background factors were associated with it. More than half of the students had visited a dentist during the previous 12 months, but only one third of students were brushing twice a day or more often. CONCLUSIONS: It may be concluded that the male Health Sciences College students seemed to have appropriate knowledge on some oral health topics, but limited knowledge on the others. Their toothbrushing practices are still far behind the international recommendation (twice a day) and also the knowledge, why it should be done so frequently also very limited

Rapid redistribution of clathrin onto macrophage plasma membranes in response to Fc receptor-ligand interaction during frustrated phagocytosis.

We have observed increases in assembled clathrin on the plasma membrane during "frustrated phagocytosis," the spreading of macrophages on immobilized immune complexes. Resident macrophages freshly harvested from the peritoneal cavity of mice and attached to bovine serum albumin (BSA)-anti-BSA-coated surfaces at 4 degrees C had almost no clathrin basketworks on their adherent plasma membrane (less than 0.01 coated patch/micron 2), as observed by immunofluorescence, immunoperoxidase, and platinum-carbon replica techniques, although abundant assembled clathrin was observed in the perinuclear Golgi region. When the cells were warmed to 37 degrees C they started to spread by 4 min and reached their maximum extent by 20 min. Spreading preceded clathrin assembly at the plasma membrane. Clathrin-coated patches were first observed on the adherent plasma membrane at 6 min. Between 12 and 20 min assembled clathrin coats appeared on both adherent and nonadherent plasma membranes with a concomitant decrease in identifiable clathrin in the perinuclear region. A new steady state emerged by 2 h, as perinuclear clathrin began to reappear. At 20 min at 37 degrees C the adherent plasma membranes of macrophages spreading on BSA alone had 0.9 coated patch/micron 2, whereas in cells spread on immune complex-coated surfaces, the clathrin patches increased, dependent on ligand concentration, to a maximum of 2.1 coated patches/micron 2. Because frustrated phagocytosis of immune complex-coated surfaces at 37 degrees C increased the area of adherent plasma membrane, the total area coated by clathrin basket-works increased 5-fold (28 micron 2/cell) as compared with cells plated on BSA alone (5.6 micron 2/cell) and 200-fold as compared with cells adhering to immune complexes at 4 degrees C. We then determined that macrophages cultured on BSA-coated coverslips for 24 h already have abundant surface clathrin. When immune complexes were formed by the addition of anti-BSA IgG to already spread macrophages cultured on BSA-coated coverslips for 24 h, clathrin assembled at the sites of ligand-receptor interaction even at 4 degrees C, before spreading, and a 2.6-fold increase in assembled clathrin was observed on the adherent plasma membrane of cells on immune complexes as compared with cells on BSA alone. Clathrin was reversibly redistributed to the Golgi region, returning to the steady state by 2 h.(ABSTRACT TRUNCATED AT 400 WORDS