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 415 records · Page 23Linked to original sources
PubMed1979

[Changes in rabbit thymus lymphoid tissue after administration of pyrogenal and hydrocortisone].

After a single administration of pyrogenal (0.2 and 5 mkg/kg) and hydrocortisone (100 mg/kg) histological changes in the rabbit thymus have been studied and compared with the level of 11-oxycorticosteroids (11-OCS) in blood of the animals under investigation. Hydrocortisone, while producing a considerable rise in the level of 11-OCS, increases the number of degenerating cells, inhibits mitotic activity and decreases the amount of lymphocytes per stipulated area unit in the cortical substance. Changes produced in the thymus after pyrogenal administration are similar to those produced by hydrocortisone administration but are pronounce much weaker, that is connected with concentration of corticosteroids circulating in blood.

11-Hydroxycorticosteroids↗
PubMed1979

Experience of changing pyrogenicity in albumin solutions.

A number of production lots of an intravenous preparation of 4.3 g/dl of human albumin failed to EP pyrogen test when tested in three rabbits. Several lots were reprocessed and subsequently proved satisfactory but over thirty lots were placed in storage and monitored by both the EP test and by using the LAL test over a period up to 650 days. The majority of the lots showed a steady fall in the pyrogen response by both tests. These lots were removed from storage and reprocessed by sterile filtration and dispensing into new glass containers. Further examination of the product showed it to be satisfactory in all regards. The product of several lots was used in treatment episodes involving the use of cell separators and shown to be satisfactory in clinical use. The remaining lots were also issues for general clinical use without incident.

Animals↗
PubMed1980

Release of an endogenous pyrogen from guinea pig leukocytes: the role of T lymphocytes and correlation with suppression (desensitization) of delayed hypersensitivity.

The pathogenesis of fever in delayed hypersensitivity (DH) was studied in guinea pigs immunized with either ovalbumin or bovine gamma-globulin in complete Freund's adjuvant. In vitro incubation of sensitized lymphocytes with the specific antigen used for immunization resulted in the elaboration of a lymphokine-like factor that activated either monocytes or neutrophils to release endogenous pyrogen (EP), the protein that causes fever. Specifically sensitized T cells appeared to be responsible for release of this EP-inducing factor. Desensitization of the dermal DH response to antigen was produced by several large injections of antigen and was associated with a reduced capacity of lymphocytes from such animals to activate phagocytic cells to release EP. This may explain the reduced fever (pyrogenic tolerance) that occurs when repeated injections of antigen are given to sensitized animals. Fever and the dermal response to DH seem to be closely linked reactions that have evolved to defend the host against invading pathogens. In both reactions, phagocytic cells appear to be activated by lymphokines derived from T lymphocytes specifically responding to microbial antigens.

Animals↗
PubMed1984

[Formation of endogenous pyrogen by mononuclear phagocytes].

Production of endogenous pyrogen by human and rabbit blood monocytes in response to stimulation with agents of different origin was studied by inhibitory analysis under comparable conditions. Actinomycin D and cytochalasin B were applied. New evidence was obtained about an important role in the mechanism of activation of mononuclear phagocytes of initial interaction between a stimulating agent and the leukocyte membrane and of the biphasic process of endogenous pyrogen production.

Animals↗
PubMed1978

[Effect of chronic pyrogenal stress on the mitotic regime and quantity of DNA-synthesizing cells in the epithelium of the cornea and tongue of white rats].

The effect of prolonged stress on mitotic regimen and the number of DNA-synthesizing cells in the corneal and tongue epithelium was studied on a model of pyrogenal stress. A five-day pyrogenal administration led to a 1.7-fold reduction of te number of mitoses in the corneal and tongue epithelium. Reduction in number of dividing cells was not associated with the change in the rate of mitosis. The percentage of pathological mitoses in the corneal epithelium of intact rats was 6.1, and it failed to change in stress. In control rats the labeled nuclei index in the corneal and tongue epithelium constituted 12.6 and 10.8. It was similar with the corresponding indices in experimental animals (12.2 and 12.2).

11-Hydroxycorticosteroids↗
PubMed1978

Enhanced lethality and tissue levels of chloroquine in rats pretreated with pyrogen.

The lethality, and concentrations of chloroquine in plasma, brain liver and heart, in control and pyrogen-treated rats were investigated. Pyrogen treatment increased the lethality, the convulsive activity, plasma and myocardial concentrations of chloroquine significantly. The results suggest that the initiation of therapy with chloroquine in acute febrile conditions may require smaller than usual dosage.

Animals↗
PubMed1976

Correlation between the immunoadjuvant activities and pyrogenicities of synthetic N-acetylmuramyl-peptides or -amino acids.

A total of 14 different N-acetylmuramyl-peptides or -amino acids with or without configurations inherent to bacterial cell wall peptidoglycans were synthesized and their pyrogenicities on intravenous injection into rabbits were tested. N-Acetylmuramyl-peptides, and especially N-acetylmuramyl-L-alanyl-D-isoglutamine and N-acetylmuramyl-L-alanyl-D-isoglutaminyl-L-lysine, which were previously shown to be adjuvant-active in both induction of delayed-type hypersensitivity and stimulation of increased serum antibody levels to ovalbumin in guinea pigs, exhibited distinct pyrogenicity at as low dose as 16 mug per rabbit. However, none of the adjuvant-inactive analogues or diastereomers of the above N-acetylmuramyl-dipeptide or related compounds caused any significant febrile response in rabbits, even at a dose of 250 mug per animal.

Adjuvants, Immunologic↗
PubMed1977

Comparison of the pyrogen tests in rabbits and with limulus lysate.

In the past years an assortment of samples of plasma proteins, enzymes, vaccines and blood substitutes were tested comparatively in rabbits (pyrogen test, European Pharmacopoeia) and with the LAL test (Pyrogent, Byk-Mallinckrodt, Inc.). Specificity and sensitivity were tested with endotoxins and lipid A of gram-negative bacteria. The limulus amebocyte lysate (LAL) test gave similar results or was tenfold more sensitive than the assay in rabbits. More than 300 samples of drugs were examined by both tests. All preparations positive in the rabbit test were positive in the LAL test too. In the testing of plasma proteins the LAL test was more sensitive. The examination of 45 samples of vaccines for pyrogens gave the same result in both assays. Streptokinase does not inhibit the LAL test unspecifically. The LAL test is not an alternative but an additional method in the detection of lipopolysaccharides in drugs.

Animals↗
PubMed1977

Comparability of pyrogen tests.

The results of the rabbit pyrogen test carried out in different but similarly equipped Institutes on 36 batches of plasma substitute are comparable. If extreme variations occur in the results of the test the cause is not likely to be found in the conditions and execution of the work, as is shown by testing material from the same bottle. When the material is taken from the same bottle the results obtained by the different Institutes are similar. One explanation of the non-comparable results seems to lie in the cleaning of the bottles. It is therefore essential that manufacturers utilize properly washed bottles. Another cause of non-comparable results seems to be linked with the time factor; as it is known from the literature, pyrogen can disappear during storage.

Animals↗
PubMed1997

Are known pyrogenic cytokines responsible for fever in influenza?

The levels of interleukin (IL)-1 beta, IL-6, tumour necrosis factor (TNF)-alpha, and macrophage inflammatory protein (MIP)-1 alpha released from human peripheral blood leucocytes (PBL) following interaction with influenza virus clone 7a (virulent, produces high fever in ferrets) and A/Fiji (attenuated, produces relatively low fever in ferrets) were low and similar for the two viruses. Neither strain induced interferon (IFN)-gamma and release of IL-8 (which occurs on incubation of PBLs alone) was reduced after interaction with the two viruses. The levels of IL-1 and IL-6 detected in the plasma of infected ferrets were low and did not correlate with the onset, duration or magnitude of the fevers produced by clone 7a and A/Fiji. Relatively large amounts (100,000 pg/kg) of IL-1 and TNF-alpha were needed to produce appreciable fever in rabbits, and such quantities of IL-6 were not pyrogenic. Hence, as for previous observations, no evidence could be obtained that induction of known pyrogenic cytokines is responsible for the febrile response in influenza. The possibility that some other mediator(s) may be involved cannot be ruled out.

Animals↗
PubMed1998

Transfer of endogenous pyrogens across artificial membranes?

Synthetic high-flux dialyzer membranes used in continuous veno-venous hemofiltration are permeable to middle molecular size endogenous pyrogens, the pro-inflammatory cytokines IL-1 beta and TNF-alpha. The quantities removed by sieving are, however, negligible in vitro as well as in vivo. Adsorption of cytokines to the membrane polymer is the major mechanism of pyrogen removal. Adsorption seems to be semispecific for pro-inflammatory cytokines because levels of anti-inflammatory mediators were not changed or even increased during CVVH. Thus, CVVH may change cytokine profiles in septic patients supporting the predominance of anti-inflammatory over pro-inflammatory activity in plasma. It remains to be demonstrated whether modifications of extracorporeal blood purification systems (high-volume CVVH, plasma separation + adsorption) are able to amplify the change in cytokine profiles and whether this change influences outcome of septic patients.

Acute Kidney Injury↗
PubMed1997

Pyrogenic reactions in patients undergoing cardiac catheterization associated with contaminated glass medicine cups.

Pyrogenic reactions are potentially life-threatening complications caused by bacterial endotoxin. After two cardiac catheterization patients developed rigors the same day, the procedures were halted and a case control study was conducted. To identify case patients (persons with rigors < or = 3 hr after catheterization during September 25-November 9, 1995), we reviewed medical records of all cardiac catheterization patients who had a blood culture or received intravenous meperidine. Twelve case patients and 40 randomly selected control patients were identified. No specific catheter was associated with case patients, but exposure to intracoronary-nitroglycerin (NTG) was (odds ratio = 12.0; 95% confidence interval 2.2, 75.6). NTG or indocyanine green dye was poured into glass medicine cups previously washed in an enzyme cleaner and then sterilized. The cleaner, used for an entire day, had elevated levels of gram-negative bacteria (> 10(4) colony forming units/mL) and endotoxin (434 endotoxin units [EU]/mL]); the reprocessed cups had no live bacteria but had elevated endotoxin levels (median 2,250 EU). Exposure to contaminated glass medicine cups probably resulted in pyrogenic reactions and contributed to death in two critically ill patients.

Aged↗
PubMed1993

Molecular evolution of the staphylococcal and streptococcal pyrogenic toxin gene family.

The pyrogenic toxin (PT) family is composed of the staphylococcal enterotoxins (SE), the toxic shock syndrome toxin, and the streptococcal pyrogenic exotoxins (SPE). Whereas considerable effort has focused on characterization of PTs due to their unique biological properties, our understanding of the evolution of this gene family is incomplete. Phylogenetic relationships for members of the PT family were estimated by examining the previously reported nucleotide sequences of the genes encoding SPEA, SPEC, SEA, SEB, SEC1, SEC2, SEC3, SED, and SEE. Additionally, we present and analyze sequence data on seven previously unreported sec genes. Within the PT family, sequence divergence was partitioned in a hierarchical fashion such that mean sequence divergence ranged from 1.179 among all 16 toxin genes, 0.443 among those restricted to Staphylococcus, and 0.028 among the genes encoding 10 variants of Type C SE. Results of this study are interpreted as suggesting that the PT family consists of two large clades. One clade consists of the staphylococcal toxins SEA, SEE, and SED, being closely related to the streptococcal toxin SPEC, whereas the other clade depicts close relationships of the staphylococcal toxins SEC and SEB with the streptococcal toxin SPEA.

Amino Acid Sequence↗
PubMed1984

Group A streptococcal phage T12 carries the structural gene for pyrogenic exotoxin type A.

The structural gene for group A streptococcal pyrogenic exotoxin (SPE) type A was cloned into E. coli. DNA fragments used for cloning the toxin gene were isolated from bacteriophage T12. Toxin, present in cell lysates of E. coli clones, immunoprecipitated with antisera raised against purified SPE type A and formed a line of identity with streptococcal-derived A toxin. The cloned toxin shared the following biological activities with streptococcal A toxin: Pyrogenicity; enhancement of host susceptibility to lethal endotoxin shock; nonspecific lymphocyte mitogenicity; and alteration of immunoglobulin production. The physical location of the toxin gene on the phage T12 genome was determined.

Animals↗
PubMed1989

Evaluation in rats of the somnogenic, pyrogenic, and central nervous system depressant effects of muramyl dipeptide.

Muramyl dipeptide increased sleep during the dark-phase, but not the light-phase of the rats' sleep-awake cycle. This circadian variation may be due to the inability of MDP to increase sleep over the high baseline levels of sleep that occur during the light-phase. However, MDP was pyrogenic during the light-phase, indicating it was pharmacologically active. In the dark-phase, MDP was not pyrogenic, but when compared to concurrent vehicle-treated rats, rats treated with MDP did not demonstrate as great a fall in body temperature. At approximately equisomnogenic doses, MDP produced less potentiation of ethanol-induced loss of righting reflex than triazolam, indicating it produces less non-specific central nervous system depressant effects. These data indicate the possibility of a new generation of hypnotic agents derived from muramyl peptides.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed2000

Structural evidence for the evolution of pyrogenic toxin superantigens.

Pathogenic bacteria have evolved a wide variety of toxins to invade and attack host organisms. In particular, strains of the bacteria Staphylococcus aureus and Streptococcus pyogenes produce a family of pyrogenic toxin superantigens (PTSAgs) that can cause illness, e.g., toxic shock syndrome, or synergize with a number of other immune system disorders. The PTSAgs are all similar in size and have a conserved two-domain tertiary fold despite minimal amino acid sequence identity. The tertiary structure of PTSAg domain 1 is similar to the immunoglobulin binding motif of streptococcal proteins G and L. PTSAg domain 2 resembles members of the oligosaccharide/oligonucleotide binding fold family that includes the B subunits of the AB(5) heat-labile enterotoxins, cholera toxin, pertussis toxin, and verotoxin. The strong structural homology between the pyrogenic toxins and other bacterial proteins suggests that the PTSAgs evolved through the recombination of two smaller beta-strand motifs.

Amino Acid Motifs↗