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Biomedical subjects

F A Kapral

Publications and source records attributed to F A Kapral.

At least 37 records · Page 2Linked to original sources
PubMed1981

Immunogenicity of Staphylococcus aureus delta-toxin.

Studies were conducted to determine the immunogenicity of purified Staphylococcus aureus delta-toxin. Rabbits and guinea pigs immunized with delta-toxin incorporated into a multiple antibody, whereas animals given toxin in saline or toxin in saline with Tween 80 did not produce antibody. The immunoglobulin G (IgG) fraction isolated by chromatography on protein A-Sepharose was examined for the presence of anti-delta-toxin antibody by immunoelectrophoresis, immunodiffusion, quantitative precipitation tests, affinity chromatography, and toxin neutralization tests. Although delta-toxin-specific IgG precipitated the toxin in agar gels, the antibody did not neutralize the toxin's hemolytic activity. Delta-toxin binding to human erythrocyte membranes was demonstrated by indirect immunofluorescent staining of toxin-treated erythrocytes.

Animals↗
PubMed1981

Characterization of a bactericidal lipid developing within staphylococcal abscesses.

Extraction of staphylococcal abscesses by the Folch procedure revealed that all of the staphylocidal activity was present in the lipid fraction. Further separation of the lipids indicated that the bactericidal activity resided in the free fatty acid pool. Lipids similarly extracted from mesenteric or epididymal fat tissue, either before of after activation, did not possess comparable activity. Myristic, palmitic, palmitoleic, linoleic, and oleic acids, as well as lysolecithin, also failed to exhibit the properties of the fatty acid fraction obtained from abscess homogenates. These findings suggest the staphylocidal fatty acid is not a common host lipid.

Abscess↗
PubMed1980

Partial characterization of a bactericidal system in staphylococcal abscesses.

Since leukocytes comprise a major portion of staphylococcal abscesses, the properties of the bactericidal material in abscess homogenates were compared with those of bactericidal systems associated with leukocyte lysosomes. The bactericidal material in abscess homogenates was distinguished from the myeloperoxidase system by its resistance to heat (100 degrees C, 30 min), lack of solubility in dilute acid (0.005 N HCl), resistance to strong acid (pH 1), and insensitivity to catalase. It was differentiated from the cationic proteins by its lack of solubility in dilute acid, insensitivity to iron (0.1 mM) or trypsin (5 mg/ml), and greater activity in solutions of increased ionic strength. These characteristics, together with its sensitivity to Ca2+ or albumin, suggested that the material might be lipid. Subsequent studies revealed that all the bactericidal activity resided in the lipid fraction recovered after extraction of abscess homogenates by the Dole procedure.

Abscess↗
PubMed1980

Formation of intraperitoneal abscesses by Staphylococcus aureus.

Certain Staphylococcus aureus strains, when inoculated into the peritoneal cavity of mice, were clumped and surrounded by a thick layer of leukocytes. After being enclosed with a connective tissue capsule, the structures histologically resembled staphylococcal abscesses. Of four strains examined, all were destroyed within abscesses, although at different rates. Abscess homogenates possessed bactericidal activity toward staphylococci, and this activity was associated with the sedimentable fraction of the homogenates. Leukocytes did not appear to be responsible for the bactericidal activity. Appreciable quantities of alpha toxin accumulated in these abscesses even without multiplication of the organisms. This model infection offers opportunities for studying some aspects of staphylococcal host-parasite interactions occurring in localized lesions.

Abscess↗
PubMed1979

Levels of exfoliatin antitoxin in pooled human serum globulin.

The potential value of human serum globulin for treatment of patients with the staphylococcal scalded-skin syndrome was determined by measuring the exfoliatin antitoxin content of globulin pools. Of 16 lots tested, only four had detectable antitoxin activity, and in these the levels were minimal. These findings suggest that pooled serum globulin is not a practical source of exfoliatin antitoxin.

Animals↗
PubMed1978

Increased tissue conductance and ion transport in guinea pig ileum after exposure to Staphylococcus aureus delta-toxin in vitro.

Prior studies had shown that Staphylococcus aureus delta-toxin was able to inhibit water absorption in guinea pig ileum and to elevate the cyclic AMP content of this tissue, but was unable to elicit certain cyclic AMP-mediated changes in Y-1 adrenal or Chinese hamster ovary cells. Because water movement passively follows the net movement of electrolytes in the gut, this study investigated the effect of delta-toxin on ion transport in guinea pig ileum maintained in vitro. The transmural potential difference (PD) of guinea pig ileum was measured and nullified with an automatic voltage clamp. The short circuit flowing under these conditions (I(sc)) was measured, and the conductance was calculated (I(sc)/PD). Unidirectional (22)Na(+) and (36)Cl(-) fluxes were measured. In a glucose-free Ringer solution, delta-toxin caused an immediate spike in PD and I(sc), and the extent and duration of the spike generally increased with increasing toxin concentration. The conductance of ileum was increased by delta-toxin, and this effect on conductance could be blocked by lecithin, a known inhibitor of delta-toxin. Tissue in the presence of glucose did not exhibit a spike in PD or I(sc) when exposed to delta-toxin. In a glucose-free medium, delta-toxin caused a 1.5- to 2.5-fold increase in both the unidirectional absorption and secretion of Na(+) and Cl(-), whereas the net secretion of Na(+) increased above basal levels. The observation that delta-toxin causes a prompt increase in intestinal ion flux lends credence to the concept that the elevation in cellular cyclic AMP, which occurs later, is a secondary response to the toxin. The rapid increase in ion flux may reflect the ability of delta-toxin to augment intercellular movement of ions across the mucosa rather than the stimulation of transcellular processes.

Animals↗
PubMed1978

Pulmonary infection of mice with Staphylococcus aureus.

The survival of Staphylococcus aureus in the lungs of mice was studied under various conditions. Doses of 10(7) to 10(9) washed staphylococci were quantitatively introduced into the lungs after intratracheal inoculation in mice under either ether or sodium pentobarbital anesthesia. Mice were sacrificed at intervals, the lungs were excised and homogenized, and the cocci were enumerated by plate count. The 50% lethal dose was 6 x 10(8) cocci per mouse, and mice died within 24 h but without proliferation of the inoculum. Mice given 10(8) cocci intratracheally under pentobarbital anesthesia regularly survived and eliminated the organisms over a 48-h period. The use of ether anesthesia resulted in persistence of the inoculum for up to 48 h, but the organisms were then eliminated. Inability to proliferate did not appear to result from a lack of iron because pretreatment of the mice with ferric ammonium citrate or Imferon did not alter inoculum survival. Staphylococci inoculated intratracheally in mice infected with influenza virus 3 to 21 days previously showed no enhanced persistence or multiplication. Cocci preclumped with fibrinogen, inocula mixed with 10 times the number of Formalin-killed staphylococci, or inocula of the encapsulated Smith strain did not survive any better than conventional inocula, suggesting that phagocytosis might not be the sole mechanism for elimination. However, a sedimentable fraction from normal or infected lung homogenates proved either inhibitory or cidal for staphylococci in vitro.

Animals↗
PubMed1977

Effect of Staphylococcus aureus delta toxin on Chinese hamster ovary cell morphology and Y-1 adrenal cell morphology and steroidogenesis.

Since Staphylococcus aureus delta toxin previously had been shown to increase the cyclic adenosine 3',5'-monophosphate (cAMP) content of guinea pig ileum, the effect of delta toxin on such cAMP-mediated responses as morphogenesis and steroidogenesis in cultured tissue cells was examined. In contrast to cholera toxin, delta toxin did not cause spindling of Chinese hamster ovary cells. Unlike adrenocorticotropin or cholera toxin, delta toxin was unable to cause rounding of Y-1 adrenal cells or to promote steroid production by the cells. S. aureus alpha toxin and enterotoxin B were also unable to cause rounding of Y-1 adrenal cells. Omission of Ca2+ from the media still allowed for increased steroid production by adrenocorticotropin but not by delta toxin. Delta toxin at concentrations greater than 10 micrograms/ml did cause lysis of both Chinese hamster ovary and Y-1 adrenal cells. These findings suggest that the increase in intestinal cAMP levels caused by delta toxin is mediated through a mechanism different from that initiated by cholera toxin.

Adrenal Gland Neoplasms↗
PubMed1976

Effect of fatty acids on Staphylococcus aureus delta-toxin hemolytic activity.

The lysis of human erythrocytes by Staphylococcus aureus delta-toxin proceeded without a lag and was directly proportional to toxin concentration and temperature of incubation. Lysis was complete within 8 min. Addition of saturated, straight-chain fatty acids of 13 to 19 carbons increased the activity of delta-toxin, whereas those with 21 to 23 carbons were inhibitory. Palmitic acid was the fatty acid most active in augmenting delta-toxin, but its effect could be abolished by the simultaneous addition of either tricosanoic acid or egg lecithin.

Fatty Acids↗
PubMed1976

Inhibition of water absorption in the intestine by Staphylococcus aureus delta-toxin.

Water absorption in intestinal segments was monitored by measuring the concentration of polyethylene glycol, a nonabsorbable reference marker, in a balanced salt solution continuously perfused through the lumen. Staphylococcus aureus delta-toxin inhibited water absorption in rabbit jejunum and ileum perfused in vivo and in guinea pig ileum perfused in vitro. Cholera toxin also interfered with water absorption in guinea pig ileum maintained in vitro, but S. aureus enterotoxin B had no demonstrable effect on this tissue.

Animals↗
PubMed1976

Increased cyclic adenosine 3',5'-monophosphate content in guinea pig ileum after exposure to Staphylococcus aureus delta-toxin.

To compare Staphylococcus aureus delta-toxin with cholera toxin, which is known to increase cellular cyclic adenosine 3',5'-monophosphate (cAMP), studies were undertaken to determine the effect of delta-toxin on the cAMP content of guinea pig ileum maintained in vitro. Concentrations of delta-toxin as low as 0.40 mug/ml increased cAMP levels in guinea pig ileum after 2 h of incubation. Histological damage was seen in ileum exposed for 2 h to delta-toxin concentrations of 100 mug/ml. As little as 3 mug of delta-toxin increased vascular permeability in guinea pig skin. Permeability changes became evident within 5 min and were maximal within 6 h, whereas those produced by cholera toxin required 24 h to become maximal. Benadryl did not interfere with the ability of these toxins to alter vascular permeability. Purified egg lecithin reduced the effectiveness of delta-toxin in the skin but did not inhibit cholera toxin. Delta-toxin in concentrations as low as 0.1 mug/ml caused dislodgement of HeLa cells in tissue cultures. Therefore, delta-toxin appears unique in being the only bacterial toxin, currently known to alter water absorption in the ileum, that is capable of both increasing cAMP levels and being cytotoxic. These findings suggest a possible role for delta-toxin in the pathogenesis of staphylococcal enteritis.

Animals↗
PubMed1976

Subcutaneous multiplication of exfoliatin-producing staphylococci.

After subcutaneous inoculation of approximately 10(6) cocci, changes in staphylococcal populations were followed by the enumeration of organisms in excised tissues. In contrast to conventionaal Staphylococcus aureus strains, exfoliatin-producing strains were able to multiply in the subcutaneous tissues of neonatal and adult mice. Although strains capable of producing large quantities of exfoliatin were better able to proliferate than strains producing lesser amounts of toxin, it was not determined whether exfoliatin was directly responsible for the observed multiplication. Two variants exhibiting a partial loss in exfoliatin production showed minor changes in proliferative capability. A third strain, after being cured of its exfoliatin plasmid, manifested a marked reduction in exfoliatin production and was unable to multiply subcutaneously. With some strains multiplication proceeded for several hours but was then followed by a decline in the number of viable organisms. Histological sections of subcutaneous lesions revealed a rapid influx of neutrophils, but leukocytes accumulated in the region regardless of whether the organisms multiplied or were eliminated.

Animals↗
PubMed1972

Neutralization of Staphylococcus aureus exfoliatin by antibody.

Alum-precipitated exfoliatin was found to be an efficient antigen for eliciting high titers of neutralizing antibody in rabbits. Antitoxin thus produced, and transferred passively, was shown to protect neonatal mice against challenge with two to three lethal doses of preformed exfoliatin even when administration was delayed until 15 min before exfoliation began in control animals. The same dose of antitoxin afforded some protection against six to eight lethal doses of exfoliatin provided it was given before or at the time of challenge. Antitoxin, in the doses given, did not protect against infection with an exfoliatin-producing Staphylococcus aureus strain although the onset of exfoliation was delayed.

Animals↗
PubMed1971

Product of Staphylococcus aureus responsible for the scalded-skin syndrome.

Certain Staphylococcus aureus strains of phage group 2 produced a protein distinct from the alpha and delta toxins which was capable of causing generalized exfoliation in neonatal mice and presumably is responsible for the scalded-skin syndrome in humans. This protein, named "exfoliatin," was purified and found to have a molecular weight of approximately 24,000. Exfoliatin was acid-labile, rather heat-stabile, and antigenic.

Animals↗