Alpha 2-macroglobulin 'fast' forms inhibit superoxide production by activated macrophages

Mouse peritoneal macrophages activated by bacillus Calmette-Guerin (BCG) were incubated with human alpha 2-macroglobulin converted to its 'fast' form with either trypsin or methylamine before being stimulated with phorbol myrystate acetate. Both alpha 2-macroglobulin-trypsin and alpha 2-macroglobulin-methylamine inhibited macrophage production of superoxide anion (O2-) while native alpha 2-macroglobulin had little effect except at high concentration. The alpha 2-macroglobulin 'fast' forms, which bind with a Kd of about 8 nM, inhibited 50% generation of O2- (ID50) at a concentration of 7 nM while alpha 2-macroglobulin inhibited O2- production with an ID50 of 141 nM. The 'fast' forms of alpha 2-macroglobulin may play a role in the feedback regulation of inflammatory reactions.     

α2-macroglobulin ‘fast’ forms inhibit superoxide production by activated macrophages

Mouse peritoneal macrophages activated by bacillus Calmette-Guerin (BCG) were incubated with human α₂-macroglobulin converted to its ‘fast’ form with either trypsin or methylamine before being stimulated with phorbol myrystate acetate. Both α₂-macroglobulin-trypsin and α₂-macroglobulin-methylamine inhibited macrophage production of superoxide anion (O₂⁻) while native α₂-macroglobulin had little effect except at high concentration. The α₂-macroglobulin ‘fast’ forms, which bind with a K_d of about 8 nM, inhibited 50% generation of O₂⁻(ID₅₀) at a concentration of 7 nM while α₂-macroglobulin inhibited O₂⁻ production with an ID₅₀ of 141 nM. The ‘fast’ forms of α₂-macroglobulin may play a role in the feedback regulation of inflammatory reactions.     

The number of Na:K pump sites on red blood cells from HK and LK lambs

Lambs of known genotype with respect to the locus determining cation composition of red cells were obtained by selective matings. Numbers of K⁺ pump sites per cell were determined on HK and LK lambs 10–20 days postnatal by simultaneously determining [³H]ouabain binding and inhibition of active K⁺ transport. Red cells from HK lambs were indistinguishable from adult HK cells with regard to the K⁺ pump flux and number of pump sites. Cells from genetically LK lambs had pump fluxes and numbers of pump sites intermediate between those from adult HK and LK sheep. The results suggest that the change in cation composition and in the K⁺ pump during the first 60 days in genetically LK lambs can be correlated with a reduced number of K⁺ pump sites.     

Placentation in the garter snake, Thamnophis sirtalis

The structure and polysaccharide constitution of the jelly capsule of the egg of Rana pipiens is described. Microscopic examination of the jelly capsule revealed the presence of five discrete jelly layers that differed clearly in their response to selected cytochemical tests. These layers were classified as M1-through M5 from the inner to the outermost layer. A sixth layer occasionally could be observed between M3 and M4. All layers contain neutral mucopolysaccharides. In addition layers M1 and M3 contain sulphated mucopolysaccharides, M2 and M4 contain non-sulphated acid mucopolysaccharides, and layer M5 contains both sulphated and non-sulphated acid mucopolysaccharides. M2 may also contain a small quantity of sulphated mucopolysaccharides. The layer that occasionally appears between M3 and M4 is probably an area in which free acidic groups are in higher concentration than in adjacent areas rather than being a discrete jelly layer. Neither hyaluronic acid nor sialic acid was localized by the methods employed. The possible significance of some of these constituents is discussed.     

Dry Heat or Gaseous Chemical Resistance of Bacillus subtilis var. niger Spores Included Within Water-soluble Crystals

Inclusion of spores of Bacillus subtilis var. niger in water-soluble crystals increased the resistance of the spores to dry heat and to a gaseous mixture of methyl bromide and ethylene oxide. Resistance of spores in glycine crystals to dry heat at 125 C was increased 5 to 24 times compared to unprotected spores. There appeared to be a positive correlation between the size of the crystal and the degree of resistance. The resistance to dry heat of spores included in sodium chloride crystals was about six times greater than unprotected spores. A gaseous mixture of methyl bromide (964 mg/liter) and ethylene oxide (642 mg/liter) at 37% relative humidity was ineffective in sterilizing spores enclosed within these water-soluble crystals, as was ethylene oxide alone. However, if the relative humidity was sufficiently high to dissolve the crystals during exposure to the vapor, viable-spore counts were drastically reduced or were negative. The surfaces of crystals grossly contaminated with dry spores were sterilized by exposure to gaseous ethylene oxide. Sterilization of heat-labile or moisture-labile materials with a critical requirement for sterility, as in planetary probes or drugs, may be complicated by the presence of spores in naturally occurring water-soluble crystals. This phenomenon is similar to the protection afforded spores entrapped in solid plastics.     

Sporicidal Activity of Sodium Hypochlorite at Subzero Temperatures

Sodium hypochlorite was an excellent disinfectant at low temperatures. With the addition of ethylene glycol to prevent freezing, hypochlorite solutions at low free available chlorine concentrations, were effective against Bacillus subtilis var. niger spores from 0 to -40 C. The effectiveness of this decontaminant was influenced by temperature, pH, and concentration, with pH 7.2 the optimum for decontamination at all temperatures and concentrations.     

Sporicidal Activity of Peracetic Acid and β-Propiolactone at Subzero Temperatures

A method was developed to evaluate and measure the sporicidal activity of peracetic acid (PAA) and beta-propiolactone (BPL) at subzero temperatures as low as -40 C. Bacillus subtilis var. niger spores were used as the test organism. Both PAA and BPL were sporicidal at low temperatures, with PAA the more active. The temperature coefficients of the two chemicals are generally low over a range of 20 to -20 C, but increase significantly at temperatures below this. Results showed an initial lag in the PAA death rates that was directly dependent on the temperature. BPL did not show this lag time.     

Certification of Probability of Sterilization of Liquid by Filtration

Four types of hydrosol filters, two reusable (diatomaceous cylinder and fritted-glass funnel) and two disposable (asbestos pad and membrane filter) were challenged with a heavy bacterial suspension to assess their ability to produce sterile filtrates. Two of the four diatomaceous earth filters, the four fritted-glass funnels, and all of the asbestos pads tested generally gave sterile filtrates. However, only one type of filter, one of the membranes in its manufacturer's own holder, consistently gave sterile filtrates. The two other types of membranes usually gave sterile filtrates if tested in one manufacturer's holder, but all types invariably gave contaminated filtrates when tested in another manufacturer's holder. Contaminated filtrates were generally attributed to a poor reusable filter or to a faulty holder used with a disposable filter. If a high degree of certainty is required for sterile heat-labile filtrate, it is suggested that the liquid be passed through two or more filters in a previously tested and proven system.     

The role of membrane phosphoglycerate kinase in the control of glycolytic rate by active cation transport in human red blood cells

When the internal Na of human red cells is raised, both K influx and lactate production increase and become more sensitive to the inhibitory action of ouabain. This occurs with either glucose or purine nucleoside as substrate. Fresh whole hemolysates enriched with Na and Mg will convert intermediates above the triose phosphate dehydrogenase step to lactate at a rate which is slowed by ouabain. Intermediates beyond the phosphoglycerate kinase step (PGK) are metabolized at a very rapid rate which is not affected by ouabain. No metabolic effects of ouabain were found in ghost-free hemolysates. Hemoglobin-free ghosts were shown to have both triose phosphate dehydrogenase and PGK activity. The rate of this two-enzyme sequence was found to be a function of the ADP concentration, being maximal when ADP > 0.35 mM. Initial addition of ATP to the ghost system rendered the forward rate of the sequence sensitive to the inhibitory action of ouabain. When the sequence was run in reverse, no inhibitory effect of ouabain could be demonstrated. It is concluded that membrane PGK is a point at which the Na-K transport system can influence the metabolic rate and that this action is possibly exerted via a compartmentalized form of ADP which is an immediate substrate for the ghost PGK.