Centrally acting vasopressin contributes to endotoxin tolerance

1990 ◽  
Vol 258 (2) ◽  
pp. R443-R449 ◽  
Author(s):  
M. F. Wilkinson ◽  
N. W. Kasting
Keyword(s):  
Escherichia Coli ◽  
Receptor Antagonist ◽  
Arginine Vasopressin ◽  
Endotoxin Tolerance ◽  
Thermoregulatory Response ◽  
Endotoxin Challenge ◽  
E Coli ◽  
Intravenous Injections ◽  
Refractory State ◽  
V2 Antagonist

Repeated daily intravenous injections of bacterial endotoxin induce a refractory state to their usual pyrogenic effects. The neuropeptide arginine vasopressin (AVP) has been implicated in natural fever suppression and may be involved in the process of pyrogenic tolerance to intravenous endotoxin. This study was conducted to test this hypothesis. Tolerance was induced by two successive daily intravenous injections of Escherichia coli endotoxin (50 micrograms/kg) into conscious unrestrained rats. This tolerance was maintained, unaltered, after a third or fourth subsequent injection. However, bilateral administration of an AVP V1-receptor antagonist (0.43-4.3 nmol) into the ventral septal area (VSA) of the rat brain markedly enhanced the thermoregulatory response to a third or fourth endotoxin challenge compared with saline controls. The effect of the V1 antagonist was dose related. In contrast, an AVP V2 antagonist (0.43 nmol) bilaterally injected into the VSA did not affect the tolerant reaction to endotoxin. Furthermore, neither saline nor the V1 antagonist significantly affected core temperature when administered within the VSA without subsequent endotoxin. These results are consistent with the hypothesis that AVP acts as an endogenous antipyretic within the VSA during fever. Moreover, the data suggest a possible role for centrally acting vasopressin during pyrogenic tolerance to E. coli endotoxin.

scholarly journals MECHANISMS OF ENDOTOXIN TOLERANCE

1963 ◽  
Vol 117 (4) ◽  
pp. 663-674 ◽  
Author(s):  
Sheldon E. Greisman ◽  
Frank A. Carozza ◽  
J. Dixon Hills
Keyword(s):  
Phagocytic Activity ◽  
Endotoxin Tolerance ◽  
The Other ◽  
Defense System ◽  
Passive Protection ◽  
Endotoxin Challenge ◽  
E Coli ◽  
Intravenous Injections ◽  
Carbon Clearance ◽  
Tolerant Animal

Pyrogenic tolerance following 7 daily intravenous injections of 2.0 µg/kg E. coli endotoxin in albino rabbits was associated with significant increases in RES phagocytic activity as measured with colloidal carbon. Nevertheless, 4 hours after RES blockade with thorotrast (3 ml/kg), the tolerant rabbits exhibited significantly lower fever indices following intravenous endotoxin challenge than did non-tolerant control animals despite comparably depressed capacities to clear carbon from the blood. Moreover, plasma from rabbits tolerant to endotoxin induced significant tolerance in normal rabbits prepared by thorotrast blockade without enhancing the depressed carbon clearance. This passive protection extended to heterologous endotoxins. Analysis of the data indicates that RES blockade does not abolish tolerance; rather blockade resets the reactivity to endotoxin in the normal and tolerant animal, rendering both exquisitely reactive, but permitting retention of the major portion of tolerance. Apparently the tolerant animal possesses a dual endotoxin defense system. One system is abolished by thorotrast; the other is in part humoral, accounts for the greater portion of tolerance, and is thorotrast-resistant. The nature of the humoral component is not defined but is consistent with that of an opsonin with high endotoxin specificity.

scholarly journals MECHANISMS OF ENDOTOXIN TOLERANCE

1966 ◽  
Vol 124 (5) ◽  
pp. 983-1000 ◽  
Author(s):  
Sheldon E. Greisman ◽  
Edward J. Young ◽  
William E. Woodward
Keyword(s):  
Intravenous Infusion ◽  
Inflammatory Responses ◽  
Reticuloendothelial System ◽  
Continuous Intravenous Infusion ◽  
Endogenous Pyrogen ◽  
Rapid Reduction ◽  
Endotoxin Challenge ◽  
E Coli ◽  
Intravenous Infusions ◽  
Refractory State

The mechanisms underlying the pyrogenic refractory state which develops rapidly during a continuous intravenous infusion of bacterial endotoxin have been further explored. The findings demonstrate that: (a) rabbits rendered refractory to a continuous intravenous infusion of E. coli endotoxin at a standard rate (18 x 10–4 µg/min) become highly refractory to a single intravenous test bolus of endotoxin, but remain fully responsive to preformed endogenous pyrogen and to substances known to release endogenous pyrogen, i.e. influenza virus, old tuberculin in specifically sensitized rabbits, and staphylococcal enterotoxin; (b) administration of fresh whole blood from normal donors containing an average of 1.6 – 108 granulocytes fails to restore febrile responsiveness to the continuing E. coli endotoxin infusion; (c) refractory phase plasma and liver homogenates exhibit no enhanced capacity to inactivate E. coli endotoxin pyrogenicity; (d) splenectomized animals readily develop the pyrogenic refractory state during E. coli endotoxin infusions and exhibit diminished, rather than the increased inflammatory responses to intradermal endotoxin seen in sham-operated controls; (e) continuous intravenous infusions of gelatin-stabilized, heat-killed pneumococci produce sustained fevers; and (f) continuous intravenous infusions of old tuberculin into specifically sensitized animals rapidly elicit a pyrogenic refractory state. The present observations, considered together with those of other investigators, support the hypothesis that pyrogenic unresponsiveness to endotoxin involves two distinct immunologic mechanisms. In terms of this hypothesis, the rapid reduction in febrile responsiveness to endotoxin is mediated by desensitization at the cellular level. With small doses of endotoxin, such as those employed in the present studies, this desensitization is primarily specific; with larger doses, nonspecific mechanisms are superimposed. So long as the subsequent doses of endotoxin are closely spaced or continuously infused, optimal conditions are provided for cellular desensitization and pyrogenic unresponsiveness to a given quantity of endotoxin can be induced rapidly and maintained without the requirement for antibody. However, as the interval between endotoxin challenge is lengthened, cellular desensitization wanes and tolerance becomes increasingly dependent upon those antibodies directed against the common toxophore groupings responsible for endotoxin pyrogenicity which assist the reticuloendothelial system in the clearance and destruction of this molecule.

The Biogenic Amine Tyramine Modulates the Adherence of Escherichia coli O157:H7 to Intestinal Mucosa

2004 ◽  
Vol 67 (5) ◽  
pp. 878-883 ◽  
Author(s):  
MARK LYTE
Keyword(s):  
Escherichia Coli ◽  
Receptor Antagonist ◽  
Biogenic Amines ◽  
Intestinal Mucosa ◽  
Adrenergic Receptor ◽  
Host Susceptibility ◽  
Escherichia Coli O157 ◽  
Ussing Chambers ◽  
E Coli ◽  
Cecal Mucosa

The environmental factors that influence the ability of Escherichia coli O157:H7 to attach to the intestinal mucosa are incompletely understood. In the present study, the ability of one of the most common biogenic amines present in food, tyramine, to influence the ability of E. coli O157:H7 to adhere to murine cecal mucosa was examined. Ex vivo full-thickness sheets of murine cecum were mounted in Ussing chambers, which preserved the enteric nervous system innervation of the luminal epithelia and thereby allowed us to achieve a closer approximation of bacterial adherence than would be encountered in vivo. After exposure of the luminal aspect of the cecum to tyramine, E. coli O157:H7 was added for 90 min. The cecal tissue was then removed and washed, and adhered E. coli O157:H7 was enumerated using a selective medium. Tyramine significantly increased E. coli O157:H7 adherence to cecal mucosa when compared to that of controls. The 50% effective concentration of tyramine was 92.6 μM. Specific adrenergic antagonists were then employed to examine whether the effect of tyramine was mediated through α- or β-adrenergic receptors on the intestinal tissue. Pretreatment of tissues with either the α-adrenergic receptor antagonist phentolamine or the β-adrenergic receptor antagonist propranolol prevented the action of tyramine. Measurement of active transepithelial ion transport and ionic permeability in the cecal sheets before and after the addition of tyramine and E. coli O157:H7 did not show any impairment of tissue viability or transepithelial conductance. Further, tyramine did not influence either the growth of E. coli O157:H7 or the expression of the intimin attachment factor. The present findings suggest that biogenic amines, such as tyramine, present within the food matrix influence host susceptibility to E. coli O157: H7 infection.

scholarly journals The time course of calprotectin liberation from human neutrophil granulocytes after Escherichia coli and endotoxin challenge

2019 ◽  
Vol 25 (6) ◽  
pp. 369-373 ◽  
Author(s):  
Miklos Lipcsey ◽  
Katja Hanslin ◽  
Johan Stålberg ◽  
David Smekal ◽  
Anders Larsson
Keyword(s):  
Escherichia Coli ◽  
Bacterial Infections ◽  
Time Course ◽  
Kidney Injury ◽  
Neutrophil Granulocytes ◽  
Blood Samples ◽  
Endotoxin Challenge ◽  
E Coli ◽  
Kidney Injury Molecule 1

Plasma calprotectin has previously been reported as a biomarker for sepsis. The aim of the present study was to elucidate the kinetics of calprotectin release from neutrophils exposed to Escherichia coli and endotoxin. Whole blood samples were exposed to E. coli bacteria or endotoxin in vitro. Blood samples were collected after 0, 1, 2, 3 and 4 h and plasma calprotectin was analysed by particle enhanced turbidimetric immunoassay while TNF-α, IL-6, neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) were analyzed by ELISA. When neutrophils were exposed to either E. coli or endotoxin, calprotectin levels began to increase within a couple of hours after the challenge. Calprotectin increases early in response to bacterial challenge. Given the logistic advantages of the calprotectin analysis, this may be of interest for early diagnosis of bacterial infections.

Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

1967 ◽  
Vol 25 ◽  
pp. 96-97
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Electron Microscope ◽  
Uranyl Acetate ◽  
E Coli ◽  
Receptor Sites ◽  
Rigid Cell Wall ◽  
Host Cell Surface ◽  
Bacterial Viruses ◽  
Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

The Influence of Glycosylation on the Catalytic and Fibrinolytic Properties of Pro-Urokinase

1992 ◽  
Vol 68 (05) ◽  
pp. 539-544 ◽  
Author(s):  
Catherine Lenich ◽  
Ralph Pannell ◽  
Jack Henkin ◽  
Victor Gurewich
Keyword(s):  
Escherichia Coli ◽  
Mammalian Cell ◽  
Human Gene ◽  
Culture Media ◽  
Mammalian Cell Culture ◽  
Glycosylation Site ◽  
Clot Lysis ◽  
Cell Culture Media ◽  
E Coli ◽  
The Uk

SummaryWe previously found that human pro-UK expressed in Escherichia coli is more active in fibrinolysis than recombinant human pro-UK obtained from mammalian cell culture media. To determine whether this difference is related to the lack of glycosylation of the E. coli product, we compared the activity of E. coli-derived pro-UK [(-)pro-UK] with that of a glycosylated pro-UK [(+)pro-UK] and of a mutant of pro-UK missing the glycosylation site at Asn-302 [(-) (302) pro-UK]. The latter two pro-UKs were obtained by expression of the human gene in a mammalian cell. The nonglycosylated pro-UKs were activated by plasmin more efficiently (≈2-fold) and were more active in clot lysis (1.5-fold) than the (+)pro-UK. Similarly, the nonglycosylated two-chain derivatives (UKs) were more active against plasminogen and were more rapidly inactivated by plasma inhibitors than the (+)UK.These findings indicate that glycosylation at Asn-302 influences the activity of pro-UK/UK and could be the major factor responsible for the enhanced activity of E. coli-derived pro-UK.

Usefulness of a Multiplex PCR for Detection of Diarrheagenic Escherichia coli in a Diagnostic Microbiology Laboratory Setting

2016 ◽  
Vol 1 (2) ◽  
pp. 38-42 ◽  
Author(s):  
Khairun Nessa ◽  
Dilruba Ahmed ◽  
Johirul Islam ◽  
FM Lutful Kabir ◽  
M Anowar Hossain
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Clinical Laboratory ◽  
Proteinase K ◽  
Microbiology Laboratory ◽  
Pcr Assay ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Multiplex Pcr Assay ◽  
Diagnostic Microbiology

A multiplex PCR assay was evaluated for diagnosis of diarrheagenic Escherichia coli in stool samples of patients with diarrhoea submitted to a diagnostic microbiology laboratory. Two procedures of DNA template preparationproteinase K buffer method and the boiling method were evaluated to examine isolates of E. coli from 150 selected diarrhoeal cases. By proteinase K buffer method, 119 strains (79.3%) of E. coli were characterized to various categories by their genes that included 55.5% enteroaggregative E. coli (EAEC), 18.5% enterotoxigenic E. coli (ETEC), 1.7% enteropathogenic E. coli (EPEC), and 0.8% Shiga toxin-producing E. coli (STEC). Although boiling method was less time consuming (<24 hrs) and less costly (<8.0 US $/ per test) but was less efficient in typing E. coli compared to proteinase K method (41.3% vs. 79.3% ; p<0.001). The sensitivity and specificity of boiling method compared to proteinase K method was 48.7% and 87.1% while the positive and negative predictive value was 93.5% and 30.7%, respectively. The majority of pathogenic E. coli were detected in children (78.0%) under five years age with 53.3% under one year, and 68.7% of the children were male. Children under 5 years age were frequently infected with EAEC (71.6%) compared to ETEC (24.3%), EPEC (2.7%) and STEC (1.4%). The multiplex PCR assay could be effectively used as a rapid diagnostic tool for characterization of diarrheagenic E. coli using a single reaction tube in the clinical laboratory setting.Bangladesh J Med Microbiol 2007; 01 (02): 38-42

Antagonistic activity of Bacillus subtilis strains isolated from various sources

2018 ◽  
Vol 8 (2) ◽  
pp. 354-364
Author(s):  
A. N. Irkitova ◽  
A. V. Grebenshchikova ◽  
A. V. Matsyura
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Wild Strain ◽  
Fish Farming ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
E Coli ◽  
Long Period ◽  
Test Culture ◽  
Agar Media

<p>An important link in solving the problem of healthy food is the intensification of the livestock, poultry and fish farming, which is possible only in the adoption and rigorous implementation of the concept of rational feeding of animals. In the implementation of this concept required is the application of probiotic preparations. Currently, there is an increased interest in spore probiotics. In many ways, this can be explained by the fact that they use no vegetative forms of the bacilli and their spores. This property provides spore probiotics a number of advantages: they are not whimsical, easily could be selected, cultivated, and dried. Moreover, they are resistant to various factors and could remain viable during a long period. One of the most famous spore microorganisms, which are widely used in agriculture, is <em>Bacillus subtilis</em>. Among the requirements imposed to probiotic microorganisms is mandatory – antagonistic activity to pathogenic and conditional-pathogenic microflora. The article presents the results of the analysis of antagonistic activity of collection strains of <em>B. subtilis</em>, and strains isolated from commercial preparations. We studied the antagonistic activity on agar and liquid nutrient medias to trigger different antagonism mechanisms of <em>B. subtilis</em>. On agar media, we applied three diffusion methods: perpendicular bands, agar blocks, agar wells. We also applied the method of co-incubating the test culture (<em>Escherichia coli</em>) and the antagonist (or its supernatant) in the nutrient broth. Our results demonstrated that all our explored strains of <em>B. subtilis</em> have antimicrobial activity against a wild strain of <em>E. coli</em>, but to varying degrees. We identified strains of <em>B. subtilis</em> with the highest antagonistic effect that can be recommended for inclusion in microbial preparations for agriculture.</p><p><em><br /></em><em></em></p>

NGHIÊN CỨU KHẢ NĂNG BẤT HOẠT ESCHERICHIA COLI TRONG NƯỚC BẰNG TIA CỰC TÍM VỚI SỰ HỖ TRỢ CỦA THIẾT BỊ TẠO MÀNG CHẤT LỎNG

2020 ◽  
Vol 129 (4B) ◽  
Author(s):  
Đặng Thị Thanh Lộc ◽  
Lê Văn Tuấn
Keyword(s):  
Escherichia Coli ◽  
E Coli

Công nghệ khử trùng nước không tạo ra các sản phẩm phụ độc hại ngày càng thu hút nhiều quan tâm nghiên cứu trong những năm gần đây. Nghiên cứu này trình bày kết quả khử trùng Escherichia coli trong nước bằng tia UV kết hợp với thiết bị tạo màng chất lỏng (LFFA). Sự nhạy cảm của vi khuẩn với sự khử trùng bằng UV hoặc UV/LFFA được xác định tại các điều kiện khác nhau của liều UV, tốc độ sục khí và mật độ ban đầu của vi khuẩn. Kết quả nghiên cứu cho thấy khử trùng bằng tia UV kết hợp với LFFA mang lại hiệu quả khử trùng cao hơn so với UV thông thường. Cụ thể, sự kết hợp của UV (liều UV = 20,83 mJ/cm2 và nhiệt độ phòng) và LFFA (tốc độ sục khí = 1,5 L/phút) đã bất hoạt hoàn toàn 5,4 log E. coli trong vòng 60 phút. Trong khi tại cùng một liều UV tương tự, khử trùng bằng tia UV chỉ giảm được 4,3 log vi khuẩn sau 75 phút. Nghiên cứu này hứa hẹn một khả năng áp dụng phương pháp hiệu quả để tăng cường hoạt tính diệt khuẩn của tia UV, nhằm giải quyết các mối quan tâm gần đây trong khử trùng nước.

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