Electron microscopy of phages in serotypes of Actinobacillus actinomycetemcomitans.

Actinobacillus actinomycetemcomitans, Actinobacillus ureae, Haemophilus aphrophilus, Haemophilus paraphrophilus, Haemophilus influenzae, Haemophilus parainfluenzae, Pasteurella haemolytica and Pasteurella multocida strains were examined by transmission electron microscopy for the presence of bacteriophages. Phages were detected in serotype a (SUNY 75) and e (UOH 1705) and in the fresh clinical isolates UOH Q1243 and UOH Q1247 of A. actinomycetemcomitans.

Application of multivariate analyses of enzymic data to classification of members of the Actinobacillus-Haemophilus-Pasteurella group.

Outer membrane vesicles and fragments from Actinobacillus actinomycetemcomitans, Actinobacillus lignieresii, Actinobacillus ureae, Haemophilus aphrophilus, Haemophilus paraphrophilus, Haemophilus influenzae, Haemophilus parainfluenzae, Pasteurella haemolytica, and Pasteurella multocida were isolated and examined semiquantitatively for 19 enzyme activities by using the API ZYM micromethod. The enzyme contents of vesicles and fragments were compared with the enzyme contents of whole cells of the same organisms. Enzymic data were analyzed by using principal-component analysis and soft independent modeling of class analogy.

Effects of endotoxins from Bacteroides intermedius and Escherichia coli on cytotoxic and lysosomal activity in peritoneal macrophages from endotoxin responder and low responder mouse strains.

Peritoneal macrophages from normal mice strains (C3H/Tif and C57BL/6J) and from the endotoxin (lipopolysaccharide, LPS) low responder strain (C3H/Hej were exposed to two structurally different endotoxins from Bacteroides intermedius and Escherichia coli in vitro. Intracellular activity of a lysosomal enzyme (acid phosphatase) and macrophage mediated cytotoxic activity against a tumor cell line (L929) were tested. Both endotoxins caused increased levels of acid phosphatase activity in normal mice macrophages.

The use of frozen monocytes in phagocytosis studies.

Human monocytes were isolated from peripheral blood by Lymphoprep density-gradient centrifugation and adherence to fibronectin. The cells were loosened by ethylene-diamino-tetra-acetate (EDTA), frozen by different freezing methods, thawed, washed and compared to unfrozen cells. After freezing, thawing and washing, cell recovery was calculated and found to vary with the freezing procedure.

The use of frozen erythrocytes in macrophage studies. 2. Attachment and phagocytosis mediated by the two immunological receptors of the macrophages.

Sheep erythrocytes opsonized with IgG or C3b were frozen in various cryoprotective agents, thawed, and compared to corresponding unfrozen erythrocytes exposed to the cryoprotectants and to unfrozen erythrocytes not exposed to the cryoprotectants (controls) as test particles in macrophage attachment and phagocytosis assays. Fc-receptor-mediated attachment and phagocytosis were not influenced by the use of any cryoprotective agent tested or by freezing the erythrocytes. This was also the case with C3b-receptor-mediated attachment.

The use of frozen erythrocytes in macrophage studies. 1. Attachment to the foreign surface receptor of the macrophages.

The attachment of red cells to mouse peritoneal macrophages in vitro was tested with erythrocytes (from sheep and man) which had been subjected to different cryoprotective agents and freezing procedures. The experiments showed that with dimethylsulfoxide (DMSO) as the cryoprotective agent no difference in macrophage attachment was seen whether the erythrocytes were frozen or not. With the other cryoprotectants tested, macrophages were more efficient in attaching frozen than unfrozen erythrocytes.

The use of frozen erythrocytes in the single radial haemolysis test (SRHT) for antibodies to rubella virus.

The cryoprotection of erythrocytes from newborn chickens was investigated. The cryoprotective agents tested were neutralized polyvinylpyrrolidone (PVP), dimethylsulfoxide (DMSO) and glycerol. Best results were obtained with 10 per cent DMSO, whereas 20 per cent DMSO and glycerol were unfit for use.

Cryopreservation of sheep red blood cells. 4. Titrations of the first complement component with frozen EAC4 cells.

The cryoprotection of the sheep erythrocyte intermediate EAC4 cells, used as reagent in titration of the first complement component, Gl, was investigated. The cryoprotective agents tested were untreated polyvinylpyrrolidone (PVP), purified PVP, neutralized PVP and a hydroxyethylated potato starch of high viscosity, Avelex 1030, hydrolyzed for 40 min. Recovery of EAG4 cells after thawing was 80–90 %, with best results using untreated, purified or neutralized PVP.

Cryopreservation of hen red blood cells.

The cryoprotection of hen erythrocytes, used as reagent in virus titration, was investigated. The cryoprotective agents tested were neutralized polyvinylpyrrolidone (PVP), dimethylsulfoxide (DMSO) and glycerol. Good results were obtained with PVP, especially with PVP K15 (average molecular weight 10 000), and with DMSO, especially when used in a final concentration of 10 %, whereas glycerol was unfit for use in the concentrations tested.

Cryopreservation of sheep red blood cells. 3. Complement titrations with frozen sensitized cells.

The effect of different suspending and washing procedures for recovery of sensitized sheep erythrocytes (EA) after freezing at −196°C was investigated. Best results were obtained using gelatin-veronal-buffered saline-sucrose containing 0.15 mM-Ca and 1 mM-Mg (GVBSM-sucrose) as the suspending and first washing buffer.

Cryopreservation of sheep red blood cells. 2. Purified polyvinylpyrrolidone and hydrolyzed starch as protective agents.

The protection of sheep erythrocytes against damage at low temperature (−196°C) was investigated using purified polyvinylpyrrolidone (PVP) and hydrolyzed starch as cryoprotective agents. Identical results were obtained with untreated PVP, neutralized PVP and PVP purified by chromatography. With hydrolyzed starch the cryoprotection was dependent on the type and concentration of the starch used and on the extent of hydrolysis of the starch prior to use.

Cryopreservation of sheep red blood cells. 1. Experiments with polyvinylpyrrolidone and other protective agents.

The protection of sheep erythrocytes at freezing temperatures was investigated using glycerol, dimethylsulfoxide (DMSO), glucose and four different types of polyvinylpyrrolidone (PVP) as cryoprotective agents. Depending on type (molecular weight) and concentration good protection was obtained with PVP, whereas glycerol, DMSO and glucose were unsatisfactory. Recovery of cells after thawing was most successful when the cells had been frozen at a concentration of 1–2 × 10 cells/ml.