scholarly journals STUDIES ON THE MECHANISM OF ENDOGENOUS PYROGEN PRODUCTION

1974 ◽  
Vol 140 (4) ◽  
pp. 954-964 ◽  
Author(s):  
Phyllis Bodel

The characteristics of pyrogen production and release by human blood monocytes were investigated. A dose-response assay of monocyte pyrogen in rabbits indicated a linear relationship of temperature elevation to dose of pyrogen at lower doses. Monocytes did not contain pyrogen when first obtained, nor did they release it spontaneously even after 5 days of incubation in vitro. Pyrogen production was apparent 4 h after stimulation by endotoxin or phagocytosis, and continued for 24 h or more. Puromycin, an inhibitor of protein synthesis, prevented both initiation and continuation of pyrogen production and release. Pyrogen-containing supernates retained most pyrogenic activity during overnight incubation even in the presence of activated cells. Lymphocytes appeared to play no role in either initiation or continuation of pyrogen production in these studies.

2015 ◽  
Vol 123 (6) ◽  
pp. 1337-1349 ◽  
Author(s):  
Friederike Haerter ◽  
Jeroen Cedric Peter Simons ◽  
Urs Foerster ◽  
Ingrid Moreno Duarte ◽  
Daniel Diaz-Gil ◽  
...  

Abstract Background The authors evaluated the comparative effectiveness of calabadion 2 to reverse non-depolarizing neuromuscular-blocking agents (NMBAs) by binding and inactivation. Methods The dose–response relationship of drugs to reverse vecuronium-, rocuronium-, and cisatracurium-induced neuromuscular block (NMB) was evaluated in vitro (competition binding assays and urine analysis), ex vivo (n = 34; phrenic nerve hemidiaphragm preparation), and in vivo (n = 108; quadriceps femoris muscle of the rat). Cumulative dose–response curves of calabadions, neostigmine, or sugammadex were created ex vivo at a steady-state deep NMB. In living rats, the authors studied the dose–response relationship of the test drugs to reverse deep block under physiologic conditions, and they measured the amount of calabadion 2 excreted in the urine. Results In vitro experiments showed that calabadion 2 binds rocuronium with 89 times the affinity of sugammadex (Ka = 3.4 × 109 M−1 and Ka = 3.8 × 107 M−1). The results of urine analysis (proton nuclear magnetic resonance), competition binding assays, and ex vivo study obtained in the absence of metabolic deactivation are in accordance with an 1:1 binding ratio of sugammadex and calabadion 2 toward rocuronium. In living rats, calabadion 2 dose-dependently and rapidly reversed all NMBAs tested. The molar potency of calabadion 2 to reverse vecuronium and rocuronium was higher compared with that of sugammadex. Calabadion 2 was eliminated renally and did not affect blood pressure or heart rate. Conclusions Calabadion 2 reverses NMB induced by benzylisoquinolines and steroidal NMBAs in rats more effectively, i.e., faster than sugammadex. Calabadion 2 is eliminated in the urine and well tolerated in rats.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
María Martínez-Esparza ◽  
Antonio José Ruiz-Alcaraz ◽  
Violeta Carmona-Martínez ◽  
María Dolores Fernández-Fernández ◽  
Gonzalo Antón ◽  
...  

Background and Aim. The presumed role of the inhibitory receptor LAIR-1 (CD305) in the inflammatory response suggests that it might contribute to the pathophysiology of chronic inflammatory diseases such as liver cirrhosis. We studied the LAIR-1 expression on liver macrophages and blood monocytes related to the progression of liver cirrhosis. Methods. The expression of LAIR-1 was analyzed by immunohistochemistry, flow cytometry, and Western blot. Results. We found a decreased number of macrophages expressing LAIR-1 in cirrhotic liver that could be due to a high presence of collagen, ligand of LAIR-1, in the fibrotic tissue which could downregulate its expression or interfere with the immunostaining. The expression of LAIR-1 decreased after cell differentiation, and the total content, but not the cell surface expression, increased after activation in the HL-60 human macrophage in vitro model. Blood monocytes exhibited higher LAIR-1 expression levels in cirrhotic patients, which were evident even in early clinical stages in all monocyte subsets, and greater in the “intermediate” inflammatory monocyte subpopulation. The in vitro activation of human blood monocytes did not increase its expression on the cell surface suggesting that the in vivo increase of LAIR-1 must be the result of a specific combination of stimuli present in cirrhotic patients. This represents an exclusive feature of liver cirrhosis, since blood monocytes from other chronic inflammatory pathologies showed similar or lower LAIR-1 levels compared with those of healthy controls. Conclusions. These results may indicate that monocyte LAIR-1 expression is a new biomarker to early detect liver damage caused by chronic inflammation in liver cirrhosis.


Blood ◽  
1978 ◽  
Vol 52 (3) ◽  
pp. 560-568 ◽  
Author(s):  
G de Klerk ◽  
C Kruiswijk ◽  
AA Hart ◽  
R Goudsmit

Abstract Investigations on the mouse fetal liver cell bioassay for erythropoietin (ESF) have revealed that iron present in test sera significantly dilutes the radiolabel (59Fe) and thus decreases 59Fe incorporation into heme. A method of correction for the influence of iron on the dose-response relationship of human sera is presented. Application of this method made it possible to assay human sera up to culture concentrations of 150 microliter/ml. It was shown that a corrected serum dose-response curve showed parallelism to the curve of an ESF standard preparation. This suggests similarity of the active principles and allows valid estimation of a potency ratio.


1998 ◽  
Vol 6 (1-2) ◽  
pp. 25-39 ◽  
Author(s):  
Robert Gieseler ◽  
Dirk Heise ◽  
Afsaneh Soruri ◽  
Peter Schwartz ◽  
J. Hinrich Peters

Representing the most potent antigen-presenting cells, dendritic cells (DC) can now be generated from human blood monocytes. We recently presented a novel protocol employing GM-CSF, IL-4, and IFN-γto differentiate monocyte-derived DCin vitro. Here, such cells are characterized in detail. Cells in culture exhibited both dendritic and veiled morphologies, the former being adherent and the latter suspended. Phenotypically, they were CD1a-/dim, CD11a+, CD11b++, CD11c+, CD14dim/-, CD16a-/dim, CD18+, CD32dim/-, CD33+, CD40+, CD45R0+, CD50+, CD54+, CD64-/dim, CD68+, CD71+, CD80dim, CD86+/++, MHC class I++/+++HLA-DR++/+++HLA-DP+, and HLA-DQ+. The DC stimulated a strong allogeneic T-cell response, and further evidence for their autologous antigen-specific stimulation is discussed. Although resembling a mature CD 11c+CD45R0+blood DC subset identified earlier, their differentiation in the presence of the Thl and Th2 cytokines IFN-γand IL-4 indicates that these DC may conform to mature mucosal DC.


Aldosterone, the major sodium retaining hormone in man, will stimulate active transport of sodium across the urinary bladder of the toad, Bufo marinus in vitro , at physiological concentrations of the hormone.The in vitro action of aldosterone is mimicked by steroid hormones with known mineralocorticoid properties and it is competitively inhibited by other analogues, e.g. spironolactone and cortisone. Aldosterone is bound to physiological receptor sites within the transporting epithelial cells, chiefly within the nuclei, and is displaced from these binding sites specifically by structural analogues including other mineralocorticoids. Effects of aldosterone are dependent upon availability of metabolizable substrates to support the active transport of sodium. Although the stimulation of sodium transport by aldosterone can be specifically inhibited by actinomycin D, an inhibitor of RNA synthesis, and by puromycin, an inhibitor of protein synthesis, direct evidence of stimulation of new RNA and protein synthesis during the latent period with physiological concentrations of aldosterone is still lacking. It is possible, however, that the amounts of RNA and protein that are involved are too small to be detected by available techniques. Evidence is summarized which leads us to conclude that the increased sodium transport induced by aldosterone is the consequence of a reduced resistance of the apical plasma membrane of the transporting epithelia to the entry of sodium into the transport pathway.


1990 ◽  
Vol 110 (2) ◽  
pp. 519-528 ◽  
Author(s):  
C Guidry ◽  
S Hohn ◽  
M Hook

Bovine aortic endothelial cells (BAEC), grown in vitro, are shown to synthesize and secrete factor(s) that stimulate fibroblasts to contract collagen matrices. The amount of contraction-promoting activity in the conditioned media is dependent on conditioning time and the number of cells in the culture. Production of the contraction-promoting activity continues at a high stable level for at least 5 d in serum-free medium but is abolished when the cells are exposed to an inhibitor of protein synthesis. The mechanism of action of the contraction factor(s) derived from endothelial cells was compared with that of unidentified serum factors. The endothelial cell-secreted factor(s) depends on active protein synthesis by the target cell but does not need to be present during the contraction process. The serum factors on the other hand promote collagen contraction in the absence of de novo protein synthesis but need to be continuously present. Preliminary biochemical characterization of the contraction-promoting factors produced by endothelial cells revealed properties similar to those of previously identified growth factors. However, the BAEC-secreted factor was found to be distinct from a previously identified contraction-promoting transforming growth factor beta.


1976 ◽  
Vol 81 (2) ◽  
pp. 435-448 ◽  
Author(s):  
Michael J. Wilson ◽  
Eugene Spaziani

ABSTRACT Pigmentation of the scrotum of the black-pelted rat, as expressed through melanocyte melanogenic activity, is controlled by androgens. Castration decreased in vitro incorporation of [14C] tyrosine into melanin. Testosterone pre-treatment for 4 days increased melanin radioactivity over castrate controls; the increment in vitro was prevented by an inhibitor of protein synthesis (cycloheximide) added to the incubation. However, cycloheximide only partially blocked melanin synthesis when added to tissue from animals hormone treated for 6 days in vivo, and was ineffective in tissue from intacts. Bulk protein synthesis in vitro (incorporation of [14C] tyrosine or -leucine) was not affected by castration or testosterone treatment but was uniformly inhibited by cycloheximide. The data suggest that new synthesis of specific protein in vitro was necessary for initial hormone-stimulation of melanogenesis, but with longer exposure to hormone sufficient protein was pre-synthetized in vivo to permit melanogenesis during incubation with the inhibitor. Radioautographs of epidermis incubated with [14C] tyrosine showed grains concentrated over macromolecular aggregates in melanocytes, a pattern not altered by cycloheximide. Though available for incorporation into general tissue protein. [14C] tyrosine was apparently incorporated preferentially into melanin by melanocytes. DOPA (3,4-dihydroxyphenylalanine) added to incubations in cofactor amounts did not affect decreased melanin synthesis after castration and appears, therefore, not to be rate limiting in that decrease. Tissue uptake of free [14C] tyrosine or — leucine during incubation was lower than normal in castrate epidermis; uptake was elevated by testosterone treatment. Concentrations appeared sufficient in all preparations to suggest that availability is not rate limiting for synthesis of melanin or protein; however, a possible influence on amino acid permeability for melanocytes remains undetermined. Tyrosinase activity was present in both particulate and cytosol fractions of epidermis but decreased significantly after castration only in the cytosol. Testosterone increased particulate activity after 4 days and soluble activity after 9 days of treatment. These and findings above are consistent with a model that tyrosinase is synthesized and incorporated into melanosome structure within 4 days testosterone treatment; with longer treatment synthesis may then exceed that required for melanosome assembly and tyrosinase appears in the soluble milieu.


Blood ◽  
1980 ◽  
Vol 56 (6) ◽  
pp. 1060-1067
Author(s):  
PJ Quesenberry ◽  
MA Jr Gimbrone

Colony-stimulating activity is a regulatory factor(s) that promotes differentiation of hemopoietic stem cells to mature granulocytes and macrophages; in man it has been found that blood monocytes, lymphocytes, and tissue macrophages produce it. In an effort to identify other potenitally physiologic tissue sources of colony- stimulating activity, we have studied the capacity of primary cultures of human vascular endothelial cells to produce colony-stimulating activity. Medium conditioned by incubation with endothelial cultures contained activity that promoted granulocyte-macrophage colony formation of nonadherent human and murine marrow cells. Exposure of endothelial cultures to 0.1–5.0 microgram/ml S. typhosa endotoxin for 6- 72 hr enhanced colony-stimulating activity production. Similarly, incubation of endothelial cells with lysates of human blood granulocytes, or cocultivation with intact granulocytes, resulted in increased colony-stimulating activity levels. In 7–14 day cultures, freshly isolated endothelial cells, incorporated into agar underlayers, consistently stimulated more colony formation by nonadherent human marrow cells than comparable numbers of blood monocytes. These data indicate that: (1) cultured human endothelial cells are a potent source of colony-stimulating activity; (2) they respond to endotoxin and granulocytes and their contents by producing increased amounts of CSA; and (3) they produce morea colony-stimulating activity, than human blood monocytes under standardized conditions in vitro. These observations suggest that the vascular endothelium may play a role in the physiologic regulation of granulopoiesis.


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