Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pyrogens”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1989

Immunoadjuvants enhance the febrile responses of rats to endogenous pyrogen.

The febrile responses of male Sprague-Dawley rats to a semipurified endogenous pyrogen produced from human monocytes were characterized by establishing fever dose-response curves. The animals were then injected intravenously with a number of substances that possessed the common properties of stimulating the phagocytic activity of the cells of the reticuloendothelial system and of acting as immunoadjuvants. The substances used were zymosan, lipopolysaccharide endotoxin, and muramyl dipeptide. Three days after any of these immunoadjuvants were injected, the fever sensitivity of the rats was remeasured. In each case, the slope of the fever dose-response curve tripled, and in some instances the response threshold for fever response was reduced by factors of three to eight. Furthermore, the maximum increase in body temperature produced by the endogenous pyrogen was more than doubled after immunoadjuvant treatment. By contrast latex beads, which are also phagocytized by the cells of the reticuloendothelial system but do not subsequently increase their phagocytic index nor do they enhance immune responses, had no effect on the fever sensitivity of rats in response to endogenous pyrogen. In the light of these findings, it is suggested that the febrile responses of rats to endogenous pyrogen are mediated in some manner by cells that possess some of the properties of reticuloendothelial cells. The location of these putative cells must be close to the circulation, because the immunoadjuvants used in this study were, for the most part, large molecular weight molecules that could not cross the blood-brain barrier easily.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1975

[Mechanisms of release of leucocytic pyrogen].

Mechanisms of the production and release of leucocytic pyrogen (LP) from peritoneal polymorphonuclear leucocytes (PMN) from rabbits were studied in vitro. The following results were obtained. 1) The fever curves of the microsomal and the lysosomal fractions had a later onset and were longer lasting than those from the extracellular fluid. The fever curves of the supernatant of 105,000 g showed the typical response of endogenous pyrogen characterized by a rapid onset and short lasting fever, as shown by the extracellular fluid. 2) The pyrogenicity of LP was the most potent at 60 min while the 105,000 g supernatant was most potent at 30 min after PMN incubation at 37 degrees C. 3) The extracellular protein attained the maximum level at 30 min after incubation of PMN, while the protein content in the supernatant of 105,000 g of PMN decreased gradually to the constant level at 30 min. 4) It was observed that the lysosomal degradation was stimulated with bacterial pyrogen (LPS) at 37 degrees C but LPS did not directly affect the lysosomal fraction of PMN.

Animals↗
PubMed1981

Interactions between bacterial pyrogen and proteolipid extracted fom the cerebrum (II).

Our previous finding that the cerebral proteolipid could inactivate the pyrogenicity of lipopolysaccharide (LPS) in vitro was also studied by Sephadex LH-20 column chromatography and the following results were obtained. When rabbit cerebral proteolipid was chromatographed, two main protein peaks were obtained. One appeared in the chloroform (C)/methanol (M) 6:1 and the other C/M 4:1 effluent, designated as fraction IV and fraction V, respectively. When the incubation mixture of proteolipid and LPS was chromatographed, a new protein peak appeared in the C effluent. The new protein peak was suggested to be a complex of proteolipid protein and LPS, because pyrogenicity could be detected in the protein fractions only after treatment with 2% SDS. Fraction V but not fraction IV inactivated the pyrogenicity of LPS in vitro. By re-chromatography of the incubation mixture of fraction V and LPS, a complex of protein and LPS was also eluted in the C effluent. On the other hand, by rechromatography of the incubation mixture of fraction IV and LPS, such a complex was not detected in the C effluent. The present results suggest that the proteolipid apoprotein eluted in the C/M 4:1 effluent on a Sephadex LH-20 column plays an important role in the inactivation of the pyrogenicity of LPS.

Animals↗
PubMed1991

[False positive and false negative results in testing for pyrogenic impurities].

Causes of the occurrence of pyrogenic impurities in injection and infusion preparations as well as false-positive and false-negative results possible in the pyrogen test are reported. Possibilities of excluding pyrogenic impurities in the preparations concerned and of avoiding false-positive and false-negative results in the pyrogen test are discussed.

Animals↗
PubMed1989

[The pyrogenal test in assessing body immune reactivity in acute diseases of the respiratory organs].

The authors studied the reaction of hypersensitivity of the delayed type to administration of pyrogenal in 94 patients with different acute diseases of the respiratory organs. Different changes of the pyrogenal test were accompanied by changes of leucocytosis, ESR, lymphocyte count, A, G, M immunoglobulins. An inverse relationship was found between the pyrogenal test and number of A and M immunoglobulins. The pyrogenal test may be used in outpatient conditions for preliminary evaluation of cellular immunity.

Acute Disease↗
PubMed1989

[Ultramicroscopic organization of the vascular plexus in the rabbit cerebral lateral ventricles and its changes under the effect of pyrogens].

By means of electron microscopical methods organization of various components of the vascular plexus in the rabbit cerebral lateral ventricles--ependymal and supraependymal cells, as well as capillaries, making the base of the hemato-encephalic and hemato-liquor barriers of the plexus have been studied. Injection of bacterial pyrogen (pyrogenal) to the animals is accompanied with an increasing permeability in the barriers of the vascular plexus for certain blood cells (lymphocytes, monocytes), their activation and transformation into plasma cells and macrophages. Under pyrogenal effect in the ventricle cavities activation of the supraependymal cells and intensification of their interaction with the underlying ependyma take place. In the ependymal layer local dilatation of intercellular spaces and intensification of exocytic processes are observed. The changes revealed demonstrate an active reaction of some elements of the vascular plexus to fever, dependent on injection of the bacterial pyrogens into the organism.

Animals↗
PubMed1977

A comparison of pyrogenicity and related properties seen in a suspension of Corynebacterium parvum and a gramnegative organism.

When the pyrogenic properties of C. parvum and a gramnegative organism, S. typhimurium, were compared it was found that the onset of the pyrogenic response to C. parvum was delayed relative to that of S. typhimurium and that secondary responses rarely occurred. In further experiments the interaction of C. parvum and S. typhimurium was studied. Although synergism was not demonstrated, the kinetics of the response to mixtures of the two vaccines was anomalous while pre-treatment of rabbits with C. parvum resulted in the elimination of the secondary pyrogenic response to S. typhimurium suspension. The implications of these results are discussed in terms of the known characteristics of endogenous pyrogen, lipopolysaccharide and peptidoglycan.

Animals↗
PubMed1977

Studies on pyrogenic tolerance to bacterial lipopolysaccharide in rabbits.

The development of pyrogenic tolerance was studied in rabbits treated with varying doses of E. coli lipopolysaccharide (LPS). The following results were obtained. 1) Development of pyrogenic tolerance seemed to proceed in two steps: that is, the first in which tolerance appeared rapidly and the second in which tolerance proceeded more gradually or steadily in response to repeated injections of a constant dose. 2) Tolerance induced by the latter method was not absolute; the rabbits were still sensitive to increased doses of LPS. 3) Rabbits immunized with E. coli vaccine lost their pyrogenic sensitivity of parent LPS to some extent. 4) Following intracisternal injection of LPS into tolerant rabbit, pyrogenic response was not decreased but rather enhanced in comparison with control. 5) The contents of nor-epinephrine and serotonin in the brain did not differ between normal and tolerant rabbits. 6) The mechanisms of endotoxin tolerance remain to be further studied.

Animals↗
PubMed1978

[Effect of different leukocyte pyrogen fractions on hemopoiesis].

Fractionation of leukocyte pyrogen on a column of Sephadex G-75 made it possible to obtain separately the fraction stimulating the hemopoiesis and the fraction possessing the pyrogenic activity and inhibiting the hemopoiesis. Judging by the elution profile of Sephadex column G-75, substances of high molecular weight produced a stimulating action, and of low molecular weight--pyrogenic and inhibitory action. Possibly pyrogenic and inhibitory activities are connected with different substances. The nature of the inhibitory factor requires further investigation. It may be supposed that it is a substance of chalone type.

Animals↗
PubMed1980

[Acute and chronic effects of pyrogen on mitochondrial monoamine oxidase (MAO) activity and respiratory activity in the rabbit liver (author's transl)].

Pyrogen acted on mitochondrial outer membrane or structure to increase the penetration of substrate to mitochondrial MAO. Mitochondrial respiratory activity did not change significantly after acute administration of pyrogen. With chronic administration of pyrogen, the ADP/O ratio of liver mitochondria was increased. These results suggest that the acute administration of pyrogen affects the mitochondrial outer membrane, while the chronic administration affects both the outer and inner membranes.

Animals↗
PubMed1980

[Formation of endogenous pyrogen by mononuclear phagocytes].

Incubation of alveolar macrophages of rabbits and peritoneal macrophages of the abdominal cavity washing of albino mice does not lead to endogenous pyrogen release. Peritoneal macrophages obtained after peritoneal administration to mice of thioglycollate, glycogen or heterologous blood cells do not discharge pyrogen either during incubation without additional stimulation. Macrophages isolated after intraperitoneal administration of heterologous blood cells do not exhibit pyrogenic activity possibly because of a long period of time elapsed after phagocytosis of foreign agents. The triggering of pyrogen formation by macrophages can be effected by means of in vitro phagocytosis of corpuscular particles: staphylococci or heterologous blood cells.

Animals↗
PubMed1980

[Comparison of the Limulus test with the pyrogen test in rabbits].

The Limulus test was compared with the official pyrogen test in rabbits for detecting pyrogens in medical devices for single use. 46 samples were examined. Two of them were positive in the rabbit test and also in the Limulus test; 5 samples were only positive in the Limulus test. This is in agreement with published papers. Against endotoxins of gram-negative bacteria the Limulus test is more sensitive than the common test in rabbits, but not sensitive for other pyrogens. Therefore, the Limulus test cannot replace the official rabbit test in the quality control of medical devices. We recommend the Limulus test as a quick, simple and highly sensitive screening method for gram-negative bacterial endotoxins, the most common pyrogen contaminants in drugs.

Animals↗
PubMed1994

Modulation of pyrogen-induced upregulation of endothelial cell adhesion molecules (CAMs) by interleukin-4: transcriptional mechanisms and CAM-shedding.

The pyrogens interleukin 1 (IL-1), tumor necrosis factor (TNF), and bacterial lipopolysaccharides (LPS) are known to increase endothelial cell (EC) adhesiveness for leukocytes by stimulating surface expression of various adhesion molecules. IL-4, a product of activated T-cells, was shown to affect pyrogen-mediated regulation of EC adhesion molecule surface expression. In the present study, we investigated the effect of IL-4 on pyrogen-induced upregulation of the cell adhesion molecules (CAMs) ICAM-1 (intercellular cell adhesion molecule-1), ELAM-1 (endothelial leucocyte adhesion molecule-1), and VCAM-1 (vascular cell adhesion molecule-1) in cultured human umbilical vein EC (HUVEC). Surface expression of adhesion molecules was quantified by flow cytometry, HUVEC mRNA content was estimated by Northern blot analysis, and ICAM-1 antigen in conditioned media was measured by ELISA. Incubation of HUVEC with IL-1 (100 U/ml), TNF (500 U/ml), and LPS (10 micrograms/ml) caused significant increase in ICAM-1, ELAM-1, and VCAM-1 surface expression; IL-1 caused about an eightfold increase in ICAM-1 expression, about a 13-fold increase in ELAM-1 surface expression, and about a fourfold increase in VCAM-1 expression. Coincubation of pyrogens with IL-4 (500 U/ml) differentially influenced their proadhesive effects on the HUVEC surface. In the presence of IL-4, IL-1-induced ICAM-1 upregulation was reduced, ELAM-1 upregulation was not significantly influenced by IL-4, and induction of VCAM-1 was enhanced by IL-4.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1993

[The pyrogenic activity of native and recombinant human interleukin-1 beta].

Comparative doses (100-180 ng/kg) of highly purified human native interleukin-1 beta (nIL-1 beta) and human recombinant IL-1 beta (rIL-1 beta) intravenously injected were found to cause similar changes in body temperature in rabbits. Under these conditions, stabilization of rIL-1 beta by human serum albumin (HSA) fails to affect rIL-1 beta pyrogenic activity. nIL-1 beta, 0.05-2.0 ng, injected into the PO/AH region of the brain causes dose-dependent fever in the animals. With intrahypothalamic nIL-1 beta (versus i.v. injection), the pyrogenic activity of rIl-1 beta is much lower than that of nIL-1 beta. Moreover, pyrogenicity appears to be dependent on the type of rIL-1 beta, namely on free or stabilized by HSA. The former has about 100-fold and the latter a 25-fold lower activity than the native cytokine (in terms of a dose-pyrogenic effect relationship). The findings are discussed in the light of the existence of various interleukin IL-1 beta pools.

Animals↗
PubMed1977

Studies of the sensitivity and reproducibility of pharmacopoeial pyrogen testing.

Rabbits generally numbering 27 or 36 in each experiment were injected in 1970 with doses of the pyrogenic preparation Pyrago (HUMAN) and in 1971-72 and 76 with doses of the International Pyrogen Standard (I.P.St.). The maximum temperature rises were registered, randomized and interpreted according to the requirements of the BP, USP, P. Hung. and P. Nord. 0.29 degrees C mean temperature rises proved to be non-pyrogenic according to BP and P. Hung; whereas according to the USP and P. Nord. in some percents 'to be rejected' qualifications were also established. At more increasing mean temperature rises 0.49 degrees C and 0.58 degrees C, increasing pyrogenic and decreasing 'passable' qualifications were obtained. Beginning with 0.70 degrees C and at 0.86 degrees C and 1.08 degrees C, 'passable' groups disappeared. Exclusion of the rabbits showing low sensitivity (before randomization) barely influenced the results with 3.5 ng kg-1 I.P.St. in the experiment in which the mean temperature rise was 0.49 degrees C. If, however, the mean temperature rise was higher (0.57 degrees C or 0.69 degrees C), such a selection practically resulted in the disappearance of 'passable' qualifications in the triplet groups and a great predominance of 'to be rejected' qualifications in the large groups.

Animals↗
PubMed1995

Pyrogen reactions to human serum albumin during plasma exchange.

Reactions to human serum albumin (HSA) in therapeutic plasma exchange (TPE) are rare. Nevertheless, older literature describes possible adverse effects, including specific immune responses to albumin or other proteins, and reactions due to contaminating organisms or pyrogen. During an eight day period three patients in our unit had unusual reactions after infusion of 1.5-2 L of HSA. Patient 1 had trembling that persisted for 20 min. Patient 2 had shaking for 40 min despite calcium gluconate infusion, and fever to 100.8 degrees F. Patient 3 had severe rigors that subsided after 90 min when meperidine was finally given, and fever to 103.5 degrees F. Record reviews revealed that all three patients had received HSA from the same lot, and that only one other TPE patient had received HSA from that lot. Neither our pharmacy nor the manufacturer was aware of other reactions associated with that lot. Material from a bottle only partially infused to patient 3 was negative in culture and was negative for pyrogen when retested by the manufacturer. Nevertheless, because patients 1 and 2 had each had multiple previous uneventful TPEs and because all three patients tolerated subsequent TPEs without incident when another brand of HSA was used, we conclude that these patients had pyrogen reactions to the implicated HSA lot. This experience illustrates the value of cluster recognition in arousing suspicion of unusual reactions to HSA and the value of recorded lot numbers in pursuing such suspicions. Apheresis personnel should be aware of the potential for pyrogen reactions with HSA and should record lot numbers of all fluids infused during TPE.

Adult↗
PubMed1985

Dose-dependent reduction of lipopolysaccharide pyrogenicity by polymyxin B.

Lipopolysaccharides (LPS) from Gram-negative bacteria are potent pyrogens in mammals. Polymyxin B (PB), a cationic polypeptide antibiotic, binds lipid A, the active moiety of LPS, with high affinity and abrogates several biological responses to LPS. We studied the effect of PB on pyrogenicity of purified LPS from E. coli 0111:B4 in rabbits. PB reduced the pyrogenic response to LPS in a dose-dependent manner at mass ratios (PB:LPS) from 5:1 to 100:1. Previous reports have suggested that PB is effective only at much higher doses. In our hands, PB itself is pyrogenic, unless previously gamma-irradiated. Our results confirm in vivo the anti-endotoxic action of PB.

Animals↗
PubMed1984

Effects of leukocytic pyrogen and sodium salicylate on hypothalamic thermosensitive neurons in vitro.

The effects of leukocytic pyrogen and sodium salicylate (Sal) were studied on the single-unit activities of neurons in the preoptic and anterior hypothalamus (PO/AH) recorded in tissue slices in vitro. The pyrogen applied to the immediate vicinity of the recorded neurons decreased the firing rate of the majority of warm-sensitive neurons, but had no effect on the activities of thermally insensitive neurons. The pyrogen-induced inhibition of warm-sensitive neurons was reversibly blocked by local application of Sal. The results support the view that the pyretic and antipyretic effects of intrahypothalamic pyrogen and Sal are caused by their offsetting actions on the PO/AH thermosensitive neurons.

Animals↗