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Results for “SALMONELLA TYPHOSA”

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PubMed1994

Effect of nitric oxide gas on the generation of nitric oxide by isolated blood vessels: implications for inhalation therapy.

1. We have investigated, using rat aortic rings, whether exogenous nitric oxide (NO) gas affects the activity or expression of the inducible, Ca(2+)-independent NO synthase. 2. Incubation of rings with lipopolysaccharide (LPS, S. typhosa) for 6 h resulted in a gradual loss of tissue tone, a time-dependent reduction in constrictor response to phenylephrine and significant expression and activity of Ca(2+)-independent NO synthase. 3. Following incubation of LPS-treated rings with NO gas, the expression of inducible NO synthase mRNA was still observed, although the enzyme activity was significantly reduced and there was no reduction in the response to phenylephrine. 4. Therefore, NO gas can inhibit the action but not the induction of an NO synthase likely to play a role in inflammatory states such as adult respiratory distress syndrome (ARDS). 5. These observations may explain the rebound phenomenon observed in some ARDS patients following inhalation therapy with NO gas.

Amino Acid Oxidoreductases↗

PubMed1968

The primary immune response in mice. I. The enhancement and suppression of hemolysin production by a bacterial endotoxin.

The manner in which a single injection of S. typhosa endotoxin effects the primary hemolysin response to sheep erythrocytes in the mouse has been shown to depend on the dosage, route, and time of administration of the endotoxin, as well as on the route employed for the injection of antigen. The normal production of antibody, following an intravenous or an intraperitoneal injection of red blood cells, is suppressed if the bacterial lipopolysaccharide is given before and by the same route as the antigen. The response to an intraperitoneal injection of sheep red cells is also inhibited if preceded by an intravenous injection of endotoxin. By contrast, hemolysin formation to intravenous antigen is enhanced considerably by a previous intraperitoneal injection of endotoxin, and the response both to intravenous and to intraperitoneal injections of the antigen increases if the endotoxin is given by the same route either simultaneously or shortly after the foreign red cells. These findings are discussed in regard to the physiological action of bacterial endotoxins and the early events in antibody formation.

Adjuvants, Immunologic↗

PubMedDate not supplied

The role of protein synthesis in the hypothalamic mechanism mediating pyrogen fever.

The effects of inhibition of protein synthesis by anisomycin on the pathogenesis of fever and normal thermoregulatory processes were investigated in the conscious and unrestrained cat. Subcutaneous administration of 5.0-25.0 mg/kg of anisomycin prevented the fever normally evoked by an intravenous infusion of either 1.0 ml (10(8) organisms) of a 1:10 dilution of S. typhosa or 1.0-5.0 ml (3.5 x 10(5)-2.1 X 10(7) cells/ml) of endogenous pyrogen. In addition, systemic pre-treatment with anisomycin delayed and/or blocked the fever typically elicited by a direct micro-injection into the anterior hypothalamic, preoptic area (AH/POA) at AP 12.5-16.0 of 1.0 microliters of the endotoxin. Anisomycin did not alter the hyperthermic response to an anterior hypothalamic injection of either 1.0-7.0 micrograms/1.0 microliters of serotonin (5-HT) or 100.0 ng/1.0 microliters of prostaglandin (PGE). Inhibition of protein synthesis, furthermore, did not prevent the fall in body temperature usually produced by an intrahypothalamic micro-injection of 2.33-14.0 micrograms/1.0 microliters of either norepinephrine (NE) or dopamine (DA). The thermoregulatory capacity of the cat was unaffected by the administration of comparable doses of anisomycin, i.e., the animal was able to maintain normal body temperature (+/- 0.5 degrees C) when exposed to an ambient temperature of either 10 degrees C or 34 degrees C. These results strongly suggest that the synthesis of new protein within the region of the AH/POA is a functional requisite for the development of a pyrogen-induced fever.

Animals↗

PubMed1990

Comparison of endotoxins and cutaneous burn toxin as immunosuppressants.

Endotoxins of E. coli, S. typhosa and Ps. aeruginosa were injected i.p. into mice a few days before administration of the antigen sheep erythrocytes (SE). Antibody-forming cells (AFC) to SE were later enumerated in relation to dose of endotoxin given. In comparison a toxic lipid protein isolated from burned skin (cutaneous burn toxin or CBT) was similarly applied and found to be more inhibitory of the immune response than any of the three endotoxins. Considering the 50 per cent inhibitory doses on a molar basis CBT was found to be 1000 fold more immunosuppressive than the most inhibitory endotoxin. As the immune suppression which follows severe thermal injury involves failure of interleukin 2 (IL2) function, as a critical index of survival, the CBT was tested for its effects on the culture of a human IL2-dependent cell line in the presence of IL2. CBT inhibited the growth of these cells, however, endotoxin had no effect on their proliferation. Thus CBT, which arises by a thermally induced polymerization of skin lipid protein, is specific to burn injury and has a direct inhibitory effect on the immune response.

Animals↗

PubMed1982

Further studies on the mechanism of marrow granulocytic hyperplasia in mice chronically injected with endotoxin.

Marrow granulocytic hyperplasia occurs regularly in mice injected with endotoxin for 7--30 d, despite minimal elevations of serum colony-stimulating activity (CSA). Alterations in marrow granulocyte-monocyte progenitor (CFU-C) number of changes in marrow cell cycle status do not explain this hyperplasia. We have studied other mechanisms which may explain this increased granulopoiesis. CF1, BDF1 or C57bl/6J mice were infected with 10 micrograms of S. typhosa endotoxin i.p. daily for 7--20 d. Control and endotoxin injected (tolerant) sera, each with identical levels of CSA, were assayed against control marrow cells stimulated with supramaximal amounts to CSA to assess the role of serum potentiators in augmenting granulopoiesis. In six separate experiments, tolerant sera, over a 30-fold concentration range, produced a 1.7--4.0-fold potentiation of colony growth compared to control sera (P less than 0.001). No increased tolerant sera potentiation was seen over a similar concentration range when assayed against tolerant marrow. Tolerant and control splenic conditioned media, both dialysed and non-dialysed, failed to potentiate control marrow colony growth. Tolerant marrow stem cells did not show changes in CSA sensitivity, colony size distribution or differentiation, and tolerant bone or bone marrow cells did not produce increased amounts of CSA. We conclude that serum factors separate from CSA may in part explain the increased granulopoiesis seen in endotoxin injected mice. The failure of tolerant sera to potentiate tolerant marrow growth in vitro may reflect prior in vivo exposure of marrow to these potentiating factor(s).

Animals↗

PubMed1976

Kinetics of haemopoietic recovery in endotoxin-treated mice.

Kinetics of mouse spleen colony forming units were studied after intra-peritoneal injection of 1 mug/blody weight bacterial endotoxin S. typhosa. When these mice were used as unirradiated and sublethally irradiated donors, it was possible to study the effect of the endotoxin injection upon the cells. Use of the treated mice as irradiated recipients of normal cells gave information about the host effect. In treated unirradiated mice, the total nucleated cell and the CFU counts were disturbed, and 2 days later a large fraction of the CFU were found in the DNA synthesis (S) phase. This meant that injection of endotoxin generated factors affecting the kinetics of the CFU and triggering the resting CFU into the proliferative cycle. If then the mice were given supralethal irradiation and used as recipients of normal bone marrow cells, more CFU seeded to the spleen as compared to normal recipients; but the dip and the growth rate of the CFU were not changed. Hence the endotoxin-generated factors had been eliminated in 2 days. A total body sublethal irradiation by 400 rad X-ray 2 days after endotoxin injection reduced the post-irradiation dip in the recovery curve of the CFU, indicating that though the factors affecting the cell kinetics had been eliminated, the cycling CFU behaved like a growing population. During the first week, the growth rate of the CFU remained the same as in control irradiated mice. The growth rate of the spleen CFU of the endotoxin-treated mice slowed down during the second week, and their self-replicating ability was low. Fluctuations in the DNA synthesizing fraction of the spleen CFU suggested a variability in the ratio of the length of the S phase and the cell generation time.

Animals↗