scholarly journals A LABILE SERUM FACTOR IN EXPERIMENTAL ENDOTOXIN SHOCK: CROSS-TRANSFUSION STUDIES IN DOGS

1961 ◽  
Vol 114 (4) ◽  
pp. 501-508 ◽  
Author(s):  
Wesley W. Spink ◽  
James Vick
Keyword(s):  
Lethal Dose ◽  
Endotoxin Shock ◽  
Serum Factor ◽  
Initial Stage ◽  
Endotoxin Activity ◽  
Plasma Factor ◽  
Liberation Of Histamine ◽  
Control Adult

Peripheral vascular failure caused by endotoxin in the dog has an initial stage of vasoconstriction. Preliminary studies in vitro demonstrated that the constriction was due to the interaction of endotoxin with a heat-labile serum or plasma factor and platelets, resulting in the liberation of histamine. Further studies on the intact dog support and extend this concept. A standardized dose of Escherichia coli endotoxin produced fatal shock in control adult mongrel dogs within 28 hours. The characteristic pattern of changes included progressive hypotension, oliguria and anuria, hemoconcentration, and acidosis. Normal dogs were protected against endotoxin by transfusions of blood in which the essential serum factor was depleted in one of two ways. First, plasma separated from the blood of normal animals was heated at 56°C for 30 minutes, and the infused reconstituted whole blood protected normal dogs. Protection was not afforded by unheated reconstituted blood. Second, blood from immune dogs obtained within 24 hours after a second lethal dose of endotoxin protected recipient dogs. However, protection was not demonstrated with blood collected 72 hours after a second injection of endotoxin. The nature of the serum factor essential for endotoxin activity is not known. It is postulated that an enzyme or enzyme system is involved, and the possible role of complement is discussed.

scholarly journals Alterations of Plasmin Activity, Plasminogen Levels and Activity of Anti-Plasmins During Endotoxin Shock in Dogs

1977 ◽  
Author(s):  
A. O. Aasen ◽  
M. J. Gallimore ◽  
K. Ohlsson ◽  
E. Amundsen
Keyword(s):  
Intravenous Infusion ◽  
Lethal Dose ◽  
Endotoxin Shock ◽  
Time Dependent ◽  
Plasmin Activity ◽  
Endotoxin Infusion ◽  
E Coli ◽  
Research Division ◽  
Late Stages

Endotoxin shock was induced in dogs by intravenous infusion of a lethal dose of E. coli endotoxin over a period of 3 hours. Typical changes of cardiovascular parameters were found and evidence of an intravascular clotting process was observed. Spontaneous plasmin activity and “immediate” and “time dependent” antiplasmin activities were determined by means of assays utilizing the chromogenic tripeptide derivative S-2251(Kabi Peptide Research Division, Mölndal, Sweden). Levels of plasminogen, α2-macrolobulin (α2-M) , and ai-antitrypsin(α1-AT) were determined immunochemically. During shock, gradually decreasing values of “immediate” antiplasmin and α2M were observed. During the late stages of shock “immediate” antiplasmin was found to be reduced by up to 89 per cent and α2M up to 50 per cent of pre endotoxin infusion values. A less marked lowering of “time dependent” antiplasmin and α1-AT also occurred during shock. These changes of plasma antiplasmins were accompanied by decreasing values of plasminogen and evidence of plasmin activity. These findings indicate that plasminogen is converted to plasmin during endotoxin shock and emphasize the role of antiplasmins in the pathophysiology of endotoxin shock.

Human platelet chemotaxis: requirement for plasma factor(s) and the role of collagen

1978 ◽  
Vol 235 (1) ◽  
pp. H23-H28 ◽  
Author(s):  
R. W. Lowenhaupt
Keyword(s):  
Structural Integrity ◽  
Human Platelet ◽  
Human Platelets ◽  
Factor Xi ◽  
Normal Plasma ◽  
Plasma Factor ◽  
Plasma Factors ◽  
Short Time

Platelets are actively mobile in plasma in vitro and, in addition, they migrate specifically and directionally toward added intact collagen (chemotaxis). Native human, bovine, and equine collagen, suspended in plasma, induce a chemotactic response in human platelets. However, heat-denatured and dinitrofluorobenzene-treated collagen fail to attract platelets. Platelets migrate directionally and specifically to intact native collagen incubated in plasma over a large distance (6 mm) in a very short time (total 15 min), as observed in a newly designed micromaze apparatus. Platelets obtained from donors deficient in plasma factors XII, IX, and VIII showed normal migration and chemotaxis in normal plasma and in their respective factor-deficient plasmas. Although nondirectional movement (mobility) was normal, platelets from a donor deficient in factor XI did not exhibit chemotaxis toward collagen in either factor XI-deficient plasma or in normal plasma. The results indicate that 1) collagen is a physiological substrate for the chemotactic phenomenon, 2) intact chemical and/or structural integrity of collagen is required for the induction of platelet chemotaxis, 3) at least one plasma constituent, factor XI, plays an essential role in the chemotactic phenomenon, and 4) contact between collagen and a plasma factor is essential for normal chemotaxis.

scholarly journals The Response of Leukemic Lymphocytes to Cortisol: A Suggested Role of Transcortin

Blood ◽  
1971 ◽  
Vol 37 (4) ◽  
pp. 463-472 ◽  
Author(s):  
SEYMOUR WERTHAMER ◽  
LEONARD AMARAL
Keyword(s):  
Protein A ◽  
Gel Filtration ◽  
Inhibitory Effect ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Absolute Requirement ◽  
Plasma Factor

Abstract Lymphocytes obtained from patients with chronic lymphocytic leukemia (CLL) respond to the in vitro presence of cortisol by depressed incorporation of precursors into RNA and protein. The decreased incorporation of uridine into RNA is the sum of (1) an inhibition in the synthesis of RNA and (2) an enhanced destruction of newly synthesized RNA. Whereas cortisol was not dependent upon plasma for the manifestation of the above effects, the presence of plasma was an absolute requirement in order for cortisol to have an inhibitory effect on the synthesis of protein. A comparison of leukemic and normal lymphocytes demonstrated that the magnitude of inhibition of precursors into RNA and protein was greater in leukemic cells. Because it is believed that the plasma factor required is transcortin, determination of transcortin levels by cortisolbinding gel filtration technics were performed. These indicated that transcortin levels of CLL plasma were about 50 per cent lower than that of the normal. Consequently, further experiments involving type-specific plasma substitutions were performed. The results obtained from these experiments indicated that the magnitude of the effect of cortisol on the synthesis of lymphocyte protein was directly related to the transcortin level of the plasma employed.

scholarly journals The Alternative Sigma Factor σE Plays an Important Role in Intestinal Survival and Virulence in Vibrio cholerae

2002 ◽  
Vol 70 (10) ◽  
pp. 5355-5362 ◽  
Author(s):  
Gabriela Kovacikova ◽  
Karen Skorupski
Keyword(s):  
Vibrio Cholerae ◽  
Sigma Factor ◽  
Parental Strain ◽  
Time Course ◽  
Lethal Dose ◽  
Alternative Sigma Factor ◽  
Growth And Survival ◽  
Infant Mouse

ABSTRACT The alternative sigma factor σΕ (RpoE) is involved in the response to extracytoplasmic stress and plays a role in the virulence of a variety of different bacteria. To assess the role of σΕ in Vibrio cholerae pathogenesis, a ΔrpoE mutant was constructed and analyzed using the infant mouse model. The results here show that σΕ contributes significantly to the virulence of V. cholerae. The ΔrpoE mutant was highly attenuated with a 50% lethal dose more than 3 logs higher than that for the parental strain, and its ability to colonize the intestine was reduced approximately 30-fold. A time course of infection revealed that the number of CFU of the ΔrpoE mutant was approximately 1 log lower than that of the parental strain by 12 h postinoculation and decreased further by 24 h. The defect in virulence in the ΔrpoE mutant thus appears to be a diminished ability to survive within the intestinal environment. The results here also show that σΕ is not required for growth and survival of V. cholerae in vitro at high temperatures but is required under other stressful conditions, such as in the presence of 3% ethanol. As in Escherichia coli, the expression of rpoE in V. cholerae is dependent upon two promoters located upstream of the gene, P1 and P2. P1 appears to be σ70 dependent, whereas the downstream promoter, P2, is positively autoregulated by σΕ.

scholarly journals Effects of serum on mammary epithelial proliferation in vitro during mammary gland development.

1975 ◽  
Vol 66 (2) ◽  
pp. 243-250 ◽  
Author(s):  
H W Hsueh ◽  
F E Stockdale
Keyword(s):  
Mammary Gland ◽  
Proliferative Response ◽  
Mammary Epithelial ◽  
Serum Factor ◽  
Epithelial Proliferation ◽  
Hypophysectomized Rats ◽  
Gland Development ◽  
Proliferation In Vitro

The proliferative response of mammary gland epithelium from nonpregnant, pregnant, and lactating mice to mammary serum factor and insulin was studied in vitro. Mammary gland epiithelium from nonpregnant and lactating animals has a delayed proliferative response to mammary serum factor and insulin when compared to the response of epithelium from pregnant animals. The results show that as the animals go through pregnancy into lactation the mammary gland epithelium becomes less responsive to mammary serum factor while it retains its responsiveness to insulin. The concentration of mammary serum factor in sera from animals at various physiological stages is constant. Sera from hypophysectomized rats, on the other hand, show a 50% drop in mammary serum factor activity. This loss of activity cannot be reversed by injecting prolactin, 17-beta-estradiol, or growth hormone into the hypophysectomized animals. A hypothesis that the mammary gland is composed of two proliferative epithelial populations is developed, and the possible role of prolactin in stimulating DNA synthesis is discussed.

scholarly journals Critical Roles of Clostridium difficile Toxin B Enzymatic Activities in Pathogenesis

2014 ◽  
Vol 83 (2) ◽  
pp. 502-513 ◽  
Author(s):  
Shan Li ◽  
Lianfa Shi ◽  
Zhiyong Yang ◽  
Yongrong Zhang ◽  
Gregorio Perez-Cordon ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Cysteine Protease ◽  
Lethal Dose ◽  
Enzymatic Activities ◽  
Target Cells ◽  
Content Type ◽  
Cytopathic Effects

TcdB is one of the key virulence factors ofClostridium difficilethat is responsible for causing serious and potentially fatal colitis. The toxin contains at least two enzymatic domains: an effector glucosyltransferase domain for inactivating host Rho GTPases and a cysteine protease domain for the delivery of the effector domain into host cytosol. Here, we describe a novel intrabody approach to examine the role of these enzymes of TcdB in cellular intoxication. By screening a single-domain heavy chain (VHH) library raised against TcdB, we identified two VHH antibodies, 7F and E3, that specifically inhibit TcdB cysteine protease and glucosyltransferase activities, respectively. Cytoplasmic expression of 7F intrabody in Vero cells inhibited TcdB autoprocessing and delayed cellular intoxication, whereas E3 intrabody completely blocked the cytopathic effects of TcdB holotoxin. These data also demonstrate for the first time that toxin autoprocessing occurs after cysteine protease and glucosyltransferase domains translocate into the cytosol of target cells. We further determined the role of the enzymatic activities of TcdB inin vivotoxicity using a sensitive systemic challenge model in mice. Consistent with thesein vitroresults, a cysteine protease noncleavable mutant, TcdB-L543A, delayed toxicity in mice, whereas glycosyltransferase-deficient TcdB demonstrated no toxicity up to 500-fold of the 50% lethal dose (LD50) when it was injected systemically. Thus, glucosyltransferase but not cysteine protease activity is critical for TcdB-mediated cytopathic effects and TcdB systemic toxicity, highlighting the importance of targeting toxin glucosyltransferase activity for future therapy.

TH17 Cells Mediate Extensive Skin Pathology in Acute GVHD.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2166-2166
Author(s):  
Michael J. Carlson ◽  
Jonathan S. Serody
Keyword(s):  
T Cells ◽  
Th17 Cells ◽  
Acute Gvhd ◽  
Fluorescent Microscopy ◽  
Lethal Dose ◽  
Flow Cytometric Analysis ◽  
Th2 Cells ◽  
Ifn Gamma

Abstract INTRODUCTION: Cytokines play an integral role in the development of acute graft-versus-host disease (GVHD). In particular, IFN-gamma has been ascribed both pathologic as well as protective roles in murine models of GVHD. IFN-gamma is the trademark cytokine produced by differentiated T helper (TH) type 1 CD4+ T cells, whereas IL-4 is a characteristic cytokine produced by TH2 cells. Although a number of studies have investigated the role each of these cytokines have in development or inhibition of GVHD, little evidence has been gathered regarding the role of IL-17 producing T cells (TH17). TH17 cells have been attributed to mediating pathology in several autoimmune conditions that once were thought to be uncontrolled TH1 responses. IL-17 is a proinflammatory cytokine secreted exclusively by T cells that induces production of other proinflammatory cytokines by epithelial cells, macrophages, endothelial cells and fibroblasts. Elevated levels of IL-17 have been observed in rheumatoid arthritis, multiple sclerosis, and inflammatory bowl disease. METHODS: Given the highly proinflammatory properties of IL-17 we sought to examine the role of TH17s in acute GVHD. Sort purified naive CD4+ effectors (CD4+/CD25-/CD62Lhi) from C57BL/6 mice were cultured under TH17 polarizing conditions for 11 days. Two rounds of anti-CD3 + anti-CD28 stimulation in the presence of TH17 inducing cytokines yielded a culture in which >90% of the cells were producing IL-17 with minimal production of IFN-gamma. These cells were transferred into lethally irradiated B6D2 recipients at various doses with whole splenic T cells. The results demonstrated that a sub-lethal dose of T cells could be made lethal by substituting 1×106 naive whole T cell effectors for TH17s. Interestingly, substitution of 2×106 TH17s did not cause significant mortality, however typical signs of GVHD (hunching, weight loss, fur ruffling) were observed. In addition, transfer of TH17s alone caused significant morbidity with skin ulceration and extensive loss of fur. In a minority of mice TH17s alone were sufficient to induce lethality. To investigate the trafficking of TH17s in GVHD, we culture CD4+ naive effectors from GFP+ mice under optimal TH17 conditions and transferred these cells into irradiated B6D2 recipients. Fluorescent microscopy revealed extensive infiltration by GFP+ TH17 cells in GVHD target tissues, specifically the entire GI tract, lung, as well as liver. Additionally these cells were found extensively in secondary lymphoid organs seven days after transfer. By day 14 post-transfer the emigrated cells had undergone significant expansion. We confirmed these findings by characterizing GFP+ cells at these sites by flow cytometric analysis. CONCLUSIONS: These data demonstrate that in vitro differentiated TH17s alone can cause lethal acute GVHD and can synergize to cause lethal GVHD when given with a suboptimal dose of naive T cells. The trafficking data show that TH17s infiltrate and expand robustly in lymphoid and GVHD target organs in the first two weeks post transplanataion. Collectively these results describe a pathogenic role of TH17s in acute GVHD. Figure Figure

scholarly journals Cooperative Role of Macrophages and Neutrophils in Host Antiprotozoan Resistance in Mice Acutely Infected with Cryptosporidium parvum

2008 ◽  
Vol 76 (8) ◽  
pp. 3657-3663 ◽  
Author(s):  
Dan Takeuchi ◽  
Vickie C. Jones ◽  
Makiko Kobayashi ◽  
Fujio Suzuki
Keyword(s):  
T Cells ◽  
B Cells ◽  
Nk Cells ◽  
Cryptosporidium Parvum ◽  
Lethal Dose ◽  
Scid Mice ◽  
In Vitro Studies ◽  
Classically Activated

ABSTRACT Severe experimental infections with Cryptosporidium parvum have been reported in immunocompromised animals such as SCID mice (mice without functional T cells and B cells). In a C. parvum infection with 1 × 106 oocysts/mouse in SCID beige (SCIDbg) mice (SCID mice lacking functional NK cells), oocyst shedding was first demonstrated 18 days after infection. However, shedding was shown as early as 3 days after the same infection in SCIDbgMN mice. All of the SCIDbgMN mice died within 16 days of C. parvum infection, while 100% of the SCIDbg mice exposed to the parasite survived. SCIDbgMN mice are SCIDbg mice depleted of functional macrophages (Mφ) and neutrophils (PMN), suggesting that the severity early after C. parvum infection is strongly influenced by the functions of Mφ and PMN. All SCIDbgMN mice orally infected with a lethal dose of C. parvum survived after they were inoculated with Mφ from SCIDbg mice exposed to C. parvum (CP-Mφ) or resident Mφ previously cultured with PMN from C. parvum-infected SCIDbg mice (CP-PMN). However, all SCIDbgMN mice inoculated with CP-PMN alone or resident Mφ alone died after C. parvum infection. CP-Mφ were identified as classically activated Mφ (M1Mφ), and CP-PMN were characterized as PMN-I. In in vitro studies, resident Mφ converted to M1Mφ after transwell cultivation with CP-PMN. These results indicate that the resistance of SCIDbg mice early after C. parvum infection is displayed through the function of M1Mφ which are converted from resident Mφ influenced by CP-PMN (PMN-I).

Constitutive activation of p46JNK2 is indispensable for C/EBPδ induction in the initial stage of adipogenic differentiation

2017 ◽  
Vol 474 (20) ◽  
pp. 3421-3437 ◽  
Author(s):  
Joji Kusuyama ◽  
Tomokazu Ohnishi ◽  
Kenjiro Bandow ◽  
Muhammad Subhan Amir ◽  
Kaori Shima ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Energy Homeostasis ◽  
Early Stage ◽  
Adipogenic Differentiation ◽  
Endocrine System ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Initial Stage

Adipogenic differentiation plays a vital role in energy homeostasis and endocrine system. Several transcription factors, including peroxisome proliferator-activated receptor gamma 2 and CCAAT–enhancer-binding protein (C/EBP) α, β, and δ, are important for the process, whereas the stage-specific intracellular signal transduction regulating the onset of adipogenesis remains enigmatic. Here, we explored the functional role of c-jun N-terminal kinases (JNKs) in adipogenic differentiation using in vitro differentiation models of 3T3-L1 cells and primary adipo-progenitor cells. JNK inactivation with either a pharmacological inhibitor or JNK2-specific siRNA suppressed adipogenic differentiation, characterized by decreased lipid droplet appearance and the down-regulation of Adiponectin, fatty acid protein 4 (Fabp4), Pparg2, and C/ebpa expressions. Conversely, increased adipogenesis was observed by the inducible overexpression of p46JNK2 (JNK2-1), whereas it was not observed by that of p54JNK2 (JNK2-2), indicating a distinct role of p46JNK2. The essential role of JNK appears restricted to the early stage of adipogenic differentiation, as JNK inhibition in the later stages did not influence adipogenesis. Indeed, JNK phosphorylation was significantly induced at the onset of adipogenic differentiation. As for the transcription factors involved in early adipogenesis, JNK inactivation significantly inhibited the induction of C/ebpd, but not C/ebpb, during the initial stage of adipogenic differentiation. JNK activation increased C/ebpd mRNA and protein expression through the induction and phosphorylation of activating transcription factor 2 (ATF2) that binds to a responsive element within the C/ebpd gene promoter region. Taken together, these data indicate that constitutive JNK activity is specifically required for the initial stage differentiation events of adipocytes.

Sign in / Sign up

Export Citation Format

Share Document