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1
Effting, Cristiane, Fernando Gomes Ferreira Oliveira, Iram Moreira Mundim, Alessandro de Carvalho Cruz, Andryne Rego Rodrigues, Caroline Rego Rodrigues, Jerônimo Raimundo de Oliveira-Neto, Marianna Medeiros Barros da Cunha, Adriano de Moraes Arantes, and Luiz Carlos da Cunha. "Otimização de método analítico em HPLC-PDA para monitoração terapêutica do bussulfano oral em pacientes transplantados de células-tronco hematopoiéticas." Research, Society and Development 10, no. 6 (June 7, 2021): e48110615864. http://dx.doi.org/10.33448/rsd-v10i6.15864.
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Otimizou-se método para monitoração plasmática de bussulfano em pacientes submetidos a transplante de células-tronco hematopoiéticas (TCTH). Utilizou-se HPLC-PDA Shimadzu, coluna C18 (150 mm x 4 mm), metanol/água/acetonitrila (65:20:15, v/v/v), fluxo 1 mL min-1; UV λ = 276 nm, tempo de análise de 17 min; derivatização com dietilcarbamato de sódio, extração com acetato de etila; curva de calibração linear de 200-5000 ng mL-1. A recuperação relativa dos controles foi de 89%±0,04 (CQA = 86%; CQM = 87%; CQB = 93%) e a do PI (padrão interno) foi de 74%±0,47. A recuperação absoluta dos controles foi de 114%±0,03 (CQA = 111%; CQM = 118%; CQB = 113%), e a do PI foi de 102%±2,5. Os limites inferiores de quantificação e detecção obtidos foram, respectivamente, de 200 ng mL-1 e 40 ng mL-1. A linearidade foi analisada pela curva de calibração (200–5000 ng.mL-1) (r = 0,998). A repetibilidade (intracorrida) foi de 1,25%-11,25%, e a precisão intermediária (intercorrida), 2,17%-10,71%. A exatidão encontrada foi de 89,61%-102,18%. A estabilidade de curta duração de amostras extraídas e das soluções foi de 6,25% e 3,18% para CQB, 7,54% e 2,4% para CQA e 13,17% e 4,13% para PI, respectivamente. A estabilidade de ciclos de congelamento e descongelamento de amostras extraídas e das soluções foi de 3,64% e 2,53% para CQB, 9,09% e 5,65% para CQA e 10,32% e 4,82% para PI, respectivamente. Desta forma, foi possível validar uma técnica para determinação do bussulfano em plasma por HPLC-PDA, adequada à monitorização terapêutica de pacientes.
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Elf, Marie, Maria Svedbo Engström, and Helle Wijk. "Development of the Content and Quality in Briefs Instrument (CQB-I)." HERD: Health Environments Research & Design Journal 5, no. 3 (April 2012): 74–88. http://dx.doi.org/10.1177/193758671200500308.
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Objective: The Content and Quality in Briefs Instrument (CQB-I) was designed to develop a valid and reliable audit instrument to examine the content and quality of information in documents (briefs) created in the early stages of designing healthcare environments. Background: The importance of effective briefing has been emphasized in many research studies during the past two decades. However, there is no developed instrument for auditing the content and quality of these documents. Methods: The study had a methodological and developmental design based on an established methodology for instrument development and validation. The development process consisted of three main phases: (1) item generation and scale construction; (2) assessment of face and content validity, and (3) testing of the reliability. To obtain face and content validity, expert panels reviewed the CQB-I. Content validity was assessed using the Content Validity Index (I – CVI = item level, S – CVI = scale level). Reliability was tested by test-retest and inter-rater reliability. Results: CQB-I was found to have good content validity (I − CVI = 0.78–1.0 and S – CVI = 0.98). Inter-rater reliability was acceptable (Spearman's correlation = 0.62) and stability was considered high for both raters (83% and 88%, respectively).
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Markel, Russell W., and Jonathan B. Shurin. "Contrasting effects of coastal upwelling on growth and recruitment of nearshore Pacific rockfishes (genus Sebastes)." Canadian Journal of Fisheries and Aquatic Sciences 77, no. 6 (June 2020): 950–62. http://dx.doi.org/10.1139/cjfas-2019-0179.
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Knowledge of processes underlying recruitment is critical for understanding marine population dynamics and their response to ocean climate. We investigated the relationship between coastal upwelling and early life history of black rockfish (Sebastes melanops), a midwater aggregating species, and CQB rockfishes (a solitary benthic species complex including Sebastes caurinus, Sebastes maliger, and Sebastes auriculatus), between two oceanographically distinct years on the west coast of Vancouver Island, Canada. We analysed otolith microstructure to determine parturition and settlement dates, pelagic durations, and pre- and postsettlement growth rates. High CQB rockfish recruitment in 2005 was associated with prolonged downwelling and warm ocean temperatures, late parturition dates, fast presettlement growth, short pelagic durations, and small size-at-settlement. In contrast, high black rockfish recruitment in 2006 was associated with strong upwelling and cool ocean temperatures, slow presettlement growth, and protracted pelagic durations. Presettlement growth of both rockfish complexes increased with high sea surface temperature, but was unrelated to chlorophyll a concentration. Our results indicate that the same oceanographic conditions give rise to fast presettlement growth and short pelagic durations for both groups, but that different factors lead to strong recruitment in each.
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Baldwin, Michael. "Christopher Butterfield - CHRISTOPHER BUTTERFIELD: Trip. Quatuor Bozzini. Collection QB. CQB 1719." Tempo 72, no. 285 (June 19, 2018): 96–98. http://dx.doi.org/10.1017/s0040298218000207.
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Watanabe, Jota, and Juan C. Scornik. "Measuring Human Complement Activation by HLA Antibodies." Archives of Pathology & Laboratory Medicine 130, no. 3 (March 1, 2006): 368–73. http://dx.doi.org/10.5858/2006-130-368-mhcabh.
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Abstract Context.—The clinical significance of HLA antibodies in transplantation depends on their ability to activate complement, which is measured by the standard complement-dependent cytotoxicity test. Recent reports indicate that C3b measurement on target cells may be a better indicator of human complement activation than standard cytotoxicity. Objective.—To determine the characteristics of the test, the role of other complement components, and the potential influence of the patient's own complement activity. Design.—The T-cell deposition of multiple complement components triggered by HLA alloantibodies was evaluated by flow cytometry using normal human serum as the source of complement. Complement activity in patients' sera was measured after activation with a standard antibody. Results.—When HLA antibodies activate complement, C3b deposition is usually highest, followed by that of C4b and C5b. Deposition of C1q, C3d, iC3b, or C5b-9 was low or undetectable in this study. The C5 was activated only when relatively high levels of C3b were present. There was a critical concentration of antibody, unique for each patient, below which activation of C3 declined abruptly. The complement activity in the serum of candidates for liver, heart, and lung transplantation that was tested with a standard antibody was similar to normal serum. In contrast, kidney transplant candidates exhibited higher complement activity. Unexpectedly, serum C3 activity was retained for at least 72 hours after collection. Conclusions.—Measurement of C3b, and in some instances C4b or C5b, offers a better definition of the ability of HLA antibodies to activate human complement than tests that are in current use. The results provide a necessary baseline to conduct clinical correlation studies.
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Zhang, Lin, Lei Tong, Pengguang Zhu, Peng Huang, Zhengyu Tan, Fangling Qin, Wen Shi, et al. "Adsorption of chlortetracycline onto biochar derived from corn cob and sugarcane bagasse." Water Science and Technology 78, no. 6 (September 19, 2018): 1336–47. http://dx.doi.org/10.2166/wst.2018.407.
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Abstract Biochar was prepared from two different types of biological waste materials, corn cob (CC) and sugarcane bagasse (SB). The adsorption capacity of each class of adsorbent was determined by chlortetracycline (CTC) adsorption tests. The adsorption kinetics and isotherms of chlortetracycline onto sugarcane bagasse biochar (SBB) and corn cob biochar (CCB) were studied. Experimental results indicated that pseudo-second-order adsorption kinetics of CTC onto SBB and CCB were more reasonable than pseudo-first-order kinetics, and the adsorption kinetic model of CTC onto SBB was slightly better than that onto CCB. The maximum adsorption capacity of CTC onto SBB was 16.96 mg/g at pH 4, while the highest adsorption efficiency of CTC onto CCB was achieved at pH 5 with a maximum adsorption of 12.39 mg/g. The Freundlich isotherm model was better than the Langmuir model at illustrating the adsorption process of CTC onto SBB and CCB. These results provide a way to understand the value of specific biochars, which can be used as efficient and effective adsorbents for CTC removal from waste-water. Compared with raw pinewood, SBB and CBB were considered as alternative materials to remove antibiotics from aqueous environments.
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Cooray, Asantha. "Extragalactic background light measurements and applications." Royal Society Open Science 3, no. 3 (March 2016): 150555. http://dx.doi.org/10.1098/rsos.150555.
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This review covers the measurements related to the extragalactic background light intensity from γ-rays to radio in the electromagnetic spectrum over 20 decades in wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centred at 1 μm, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar System. The best measurements of COB come from an indirect technique involving γ-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 μm established an energetically important background with an intensity comparable to the optical background. This discovery paved the way for large aperture far-infrared and sub-millimetre observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV (EUV) background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 and 5 μm using a small aperture telescope observing either from the outer Solar System, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB.
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Bentley, D. R. "Primary structure of human complement component C2 Homology to two unrelated protein families." Biochemical Journal 239, no. 2 (October 15, 1986): 339–45. http://dx.doi.org/10.1042/bj2390339.
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The primary structure of the second component of human complement (C2) was determined by cDNA cloning and sequence analysis. C2 has 39% identity with the functionally analogous protein Factor B. The C-terminal half of C2a is homologous to the catalytic domains of other serine proteinases. C2b contains three direct repeats of approx. 60 amino acid residues. They are homologous to repeats in Factor B, C4b-binding protein and Factor H, suggesting a functional significance of the repeat in C4b and C3b binding. The repeats are also found in the non-complement proteins beta 2-glycoprotein I and interleukin-2 receptor, and this repeat family may be widespread.
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Takata, Y., T. Kinoshita, H. Kozono, J. Takeda, E. Tanaka, K. Hong, and K. Inoue. "Covalent association of C3b with C4b within C5 convertase of the classical complement pathway." Journal of Experimental Medicine 165, no. 6 (June 1, 1987): 1494–507. http://dx.doi.org/10.1084/jem.165.6.1494.
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The C5 convertase of the classical complement pathway is a complex enzyme consisting of three complement fragments, C4b, C2a, and C3b. Previous studies have elucidated functional roles of each subunit (4, 6, 7), but little is known about how the subunits associate with each other. In this investigation, we studied the nature of the classical C5 convertase that was assembled on sheep erythrocytes. We found that one of the nascent C3b molecules that had been generated by the C3 convertase directly bound covalently to C4b. C3b bound to the alpha' chain of C4b through an ester bond, which could be cleaved by treatment with hydroxylamine. The ester bond was rather unstable, with a half-life of 7.9 h at pH 7.4 and 37 degrees C. Formation of the C4b-C3b dimer is quite efficient; e.g., 54% of the cell-bound C3b was associated with C4b when 25,000 molecules of C4b and 12,000 molecules of C3b were present per cell. Kinetic analysis also showed the efficient formation of the C4b-C3b dimer; the rate of dimer formation was similar to or even faster than that of cell-bound monomeric C3b molecules. These results indicate that C4b is a highly reactive acceptor molecule for nascent C3b. High-affinity C5-binding sites with an association constant of 2.1 X 10(8) L/M were demonstrated on C4b-C3b dimer-bearing sheep erythrocytes, EAC43 cells. The number of high-affinity C5-binding sites coincided with the number of C4b-C3b dimers, but not with the total number of cell-bound C3b molecules. Anti-C4 antibodies caused 80% inhibition of the binding of C5 to EAC43 cells. These results suggest that only C4b-associated C3b serves as a high-affinity C5 binding site. EAC14 cells had a small amount of high-affinity C5 binding sites with an association constant of 8.1 X 10(7) L/M, 100 molecules of bound C4b being necessary for 1 binding site. In accordance with the hypothesis that C4b-associated C4b might also serve as a high-affinity C5-binding site, a small amount of C4b-C4b dimer was detected on EAC14 cells by SDS-PAGE analysis. Taken together, these observations indicate that the high-affinity binding of C5 is probably divalent, in that C5 recognizes both protomers in the dimers. The high-affinity binding may allow selective binding of C5 to the convertase in spite of surrounding monomeric C3b molecules.
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Janowska-Wieczorek, Anna, Leah A. Marquez-Curtis, Danila Leontyev, Donald R. Branch, Janina Ratajczak, and Mariusz Z. Ratajczak. "Studies in C4b-Deficient Mice Provide Further Evidence That Complement Cascade Orchestrates the Mobilization of Hematopoietic Stem/Progenitor Cells." Blood 120, no. 21 (November 16, 2012): 2316. http://dx.doi.org/10.1182/blood.v120.21.2316.2316.
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Abstract Abstract 2316 Introduction: Complement cascade (CC) and innate immunity have emerged as important modulators of hematopoietic stem/progenitor cell (HSPC) trafficking. We reported that the CC becomes activated in bone marrow (BM) during HSPC mobilization induced by G-CSF or AMD3100 and proposed that the generation of C5a and C5b-C9 (membrane attack complex; MAC) is required for optimal mobilization (Stem Cells 2007; 25:3093; Leukemia 2010; 24:976). While C5a induces a proteolytic microenvironment in BM that attenuates SDF-1-CXCR4 retention signals for HSPC and promotes egress of leucocytes, C5b-C9 (MAC) induces the release of a crucial chemoattractant, sphingosine-1 phosphate (S1P), from red blood cells and augments mobilization of HSPC from BM. On the other hand, C3 cleavage fragments attenuate mobilization by enhancing responsiveness of HSPC to SDF-1 retention signals thus promoting HSPC retention in BM. Thus our findings suggest that mobilization is differently regulated by the proximal and distal parts of CC (upstream and downstream of C3, respectively). We also demonstrated that C3-deficient mice (lacking C3 cleavage fragments) are easy mobilizers whereas C5-deficient mice (lacking C5 cleavage fragments and not generating MAC) mobilize HSPC very poorly (Leukemia 2009; 23:2052). C4 is part of the classical pathway of CC whose activation/cleavage is initiated by C1 and C2, releasing smaller (C4a and C2b) and larger (C4b and C2a) fragments. C2a binds with C4b to form an enzymatic complex termed C3 convertase that cleaves C3 into C3a anaphylatoxin and C3b. Aim of Study: In the present study we investigated the role of C4 in HSPC mobilization and hypothesized that C4-deficient mice are easy mobilizers, supporting the notion that the proximal part of CC is crucial for retention of HSPC in the BM microenvironment. Experimental Approach: We employed 6–8 week old C4b-deficient mice (strain B6.129S-C4btm1Crr/J from Jackson Laboratory, Bar Harbour, ME) and wild type (WT) littermates. Mice were injected subcutaneously with 250 μg/kg of human recombinant G-CSF (Amgen, Thousand Oaks, CA) or saline (control) daily for 3 days. At 6 h after the last G-CSF injection, the mice were sacrificed and blood was collected from the vena cavae. Mobilization was evaluated by determining the number of leukocytes (WBC) and colony-forming unit granulocyte-macrophages (CFU-GM) circulating in the peripheral blood (PB). We also measured the level of mouse terminal complement complex C5b-C9 (MAC) in plasma using ELISA (Kamiya) in G-CSF-mobilized and non-mobilized C4b-deficient and WT mice. Results: We found that C4b-deficient mice treated with saline have slightly higher WBC counts than WT mice and that G-CSF induced a greater increase in WBC counts in these mice than in WT mice. Based on CFU-GM counts after G-CSF mobilization, C4b-deficient mice mobilized significantly more HSPCs into PB than WT mice (p < 0.0065). These observations were consistent in all four experiments performed involving 18–20 mice per experiment. The G-CSF mobilization responses correlated with a greater increase in activation of the distal part of CC in C4b-deficient mice compared to WT mice, as evidenced by C5b-C9 levels evaluated by ELISA. Conclusions: Our data indicate that C4-deficient mice are easy mobilizers, thus supporting a role for the proximal part of CC in retention of HSPC in BM. Furthermore, mobilization of HSPC in C4b-deficient mice correlated with activation of the distal part of CC and generation of C5b-C9 (MAC) suggesting that activation of the distal part of CC is crucial for egress of HSPCs into PB. Moreover, activation of the distal part of CC in C4-deficient mice that have defective activation of the proximal part of CC indicates that C5 may be cleaved in a C3-independent manner by other proteolytic enzymes present in blood plasma. Finally, our data further support that mobilization is part of a more general immune response in which all complement components, including C4, play a significant role. Disclosures: No relevant conflicts of interest to declare.
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Bernet, John, Jayati Mullick, Yogesh Panse, Pradeep B. Parab, and Arvind Sahu. "Kinetic Analysis of the Interactions between Vaccinia Virus Complement Control Protein and Human Complement Proteins C3b and C4b." Journal of Virology 78, no. 17 (September 1, 2004): 9446–57. http://dx.doi.org/10.1128/jvi.78.17.9446-9457.2004.
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ABSTRACT The vaccinia virus complement control protein (VCP) is an immune evasion protein of vaccinia virus. Previously, VCP has been shown to bind and support inactivation of host complement proteins C3b and C4b and to protect the vaccinia virions from antibody-dependent complement-enhanced neutralization. However, the molecular mechanisms involved in the interaction of VCP with its target proteins C3b and C4b have not yet been elucidated. We have utilized surface plasmon resonance technology to study the interaction of VCP with C3b and C4b. We measured the kinetics of binding of the viral protein to its target proteins and compared it with human complement regulators factor H and sCR1, assessed the influence of immobilization of ligand on the binding kinetics, examined the effect of ionic contacts on these interactions, and sublocalized the binding site on C3b and C4b. Our results indicate that (i) the orientation of the ligand is important for accurate determination of the binding constants, as well as the mechanism of binding; (ii) in contrast to factor H and sCR1, the binding of VCP to C3b and C4b follows a simple 1:1 binding model and does not involve multiple-site interactions as predicted earlier; (iii) VCP has a 4.6-fold higher affinity for C4b than that for C3b, which is also reflected in its factor I cofactor activity; (iv) ionic interactions are important for VCP-C3b and VCP-C4b complex formation; (v) VCP does not bind simultaneously to C3b and C4b; and (vi) the binding site of VCP on C3b and C4b is located in the C3dg and C4c regions, respectively.
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Haapasalo, Karita, Taru Meri, and T. Sakari Jokiranta. "Loa loa Microfilariae Evade Complement Attack In Vivo by Acquiring Regulatory Proteins from Host Plasma." Infection and Immunity 77, no. 9 (June 15, 2009): 3886–93. http://dx.doi.org/10.1128/iai.01583-08.
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ABSTRACT Loa loa is a filarial nematode that infects humans. The adults live in subcutaneous tissues and produce microfilariae that live for several weeks in the blood circulation in order to be transmitted to another person via blood meals of a dipterian vector. As microfilariae live in continuous contact with plasma, it is obvious that they evade the complement system. We studied markers of complement activation and signs of complement regulation on Loa loa microfilariae in vivo. The microfilariae were isolated from anticoagulated blood samples of a Loa loa-infected Caucasian patient. C1q and some mannose-binding lectin but only a limited amount of C3b or C4b fragments and practically no C5 or C5b-9 were present on the microfilariae. The covalently microfilaria-bound C3 and C4 depositions were mainly inactive iC3b, C3c, and iC4b fragments indicating that microfilariae had regulated complement activation in vivo. Also, in vitro deposition of C3b onto the microfilariae upon serum exposure was limited. The patient-isolated microfilariae were found to carry the host complement regulators factor H and C4b-binding protein on the outermost layer, so called sheath. The microfilaria-bound factor H was functionally active. Binding of the complement regulators to the microfilariae was confirmed in vitro using 125I-labeled factor H and C4b-binding protein. In conclusion, our study shows that Loa loa microfilariae block complement activation and acquire the host complement regulators factor H and C4b-binding protein in blood circulation. This is the first time that binding of complement regulators onto nonviral pathogens has been demonstrated to occur in humans in vivo.
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Kinoshita, T., A. W. Dodds, S. K. A. Law, and K. Inoue. "The low C5 convertase activity of the C4A6 allotype of human complement component C4." Biochemical Journal 261, no. 3 (August 1, 1989): 743–48. http://dx.doi.org/10.1042/bj2610743.
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We have compared the C5-convertase-forming ability of different C4 allotypes, including the C4A6 allotype, which has low haemolytic activity and which has previously been shown to be defective in C5-convertase formation. Recent studies suggest that C4 plays two roles in the formation of the C5 convertase from the C3 convertase. Firstly, C4b acts as the binding site for C3 which, upon cleavage by C2, forms a covalent linkage with the C4b. Secondly, C4b with covalently attached C3b serves to form a high-affinity binding site for C5. Purified allotypes C4A3, C4B1 and C4A6 were used to compare these two activities of C4. Covalently linked C4b-C3b complexes were formed on sheep erythrocytes with similar efficiency by using C4A3 and C4B1, indicating that the two isotypes behave similarly as acceptors for covalent attachment of C3b. C4A6 showed normal efficiency in this function. However, cells bearing C4b-C3b complexes made from C4A6 contained only a small number of high-affinity binding sites for C5. Therefore a lack of binding of C5 to the C4b C3b complexes is the reason for the inefficient formation of C5 convertase by C4A6. The small number of high-affinity binding sites created, when C4A6 was used, were tested for inhibition by anti-C3 and anti-C4. Anti-C4 did not inhibit C5 binding, whereas anti-C3 did. This suggests that the sites created when C4A6 is used to make C3 convertase may be C3b-C3b dimers, and hence the low haemolytic activity of C4A6 results from the creation of low numbers of alternative-pathway C5-convertase sites.
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Pangburn, M. K., and N. Rawal. "Structure and function of complement C5 convertase enzymes." Biochemical Society Transactions 30, no. 6 (November 1, 2002): 1006–10. http://dx.doi.org/10.1042/bst0301006.
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The multisubunit enzymes of the complement system that cleave C5 have many unusual properties, the most striking of which is that they acquire their specificity for C5 following cleavage of another substrate C3. C5 convertases are assemblies of two proteins C4b and C2a (classical or lectin pathways) or C3b and Bb (alternative pathway) and additional C3b molecules. The catalytic complexes (C4b, C2a or C3b, Bb) are intrinsically unstable (t1,2 = 1–3 min) and the enzymes are controlled by numerous regulatory proteins that accelerate this natural decay rate. Immediately after assembly, the bi-molecular enzymes preferentially cleave the protein C3 and exhibit poor activity toward C5 (a Km of approx. 25 μM and a C5 cleavage rate of 0.3-1 C5/min at Vmax). Efficient C3 activation results in the covalent attachment of C3b to the cell surface and to the enzyme itself, resulting in formation of C3b-C3b and C4b-C3b complexes. Our studies have shown that deposition of C3b alters the specificity of the enzymes of both pathways by changing the Km for C5 more than 1000-fold from far above the physiological C5 concentration to far below it. Thus, after processing sufficient C3 at the surface of a microorganism, the enzymes switch to processing C5, which initiates the formation of the cytolytic membrane attack complex of complement.
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Mullick, Jayati, Akhilesh K. Singh, Yogesh Panse, Vivekanand Yadav, John Bernet, and Arvind Sahu. "Identification of Functional Domains in Kaposica, the Complement Control Protein Homolog of Kaposi's Sarcoma-Associated Herpesvirus (Human Herpesvirus 8)." Journal of Virology 79, no. 9 (May 1, 2005): 5850–56. http://dx.doi.org/10.1128/jvi.79.9.5850-5856.2005.
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ABSTRACT Recently it has been shown that kaposica, an immune evasion protein of Kaposi's sarcoma-associated herpesvirus, inactivates complement by acting on C3-convertases by accelerating their decay as well as by acting as a cofactor in factor I-mediated inactivation of their subunits C3b and C4b. Here, we have mapped the functional domains of kaposica. We show that SCRs 1 and 2 (SCRs 1-2) and 1-4 are essential for the classical and alternative pathway C3-convertase decay-accelerating activity (DAA), respectively, while the SCRs 2-3 are required for factor I cofactor activity (CFA) for C3b and C4b. SCR 3 and SCRs 1 and 4, however, contribute to optimal classical pathway DAA and C3b CFA, respectively. Binding data show that SCRs 1-4 and SCRs 1-2 are the smallest structural units required for measuring detectable binding to C3b and C4b, respectively. The heparin-binding site maps to SCR 1.
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Tibi, Rigobert, Lisa Linville, Christopher Young, and Ronald Brogan. "Classification of Local Seismic Events in the Utah Region: A Comparison of Amplitude Ratio Methods with a Spectrogram‐Based Machine Learning Approach." Bulletin of the Seismological Society of America 109, no. 6 (October 22, 2019): 2532–44. http://dx.doi.org/10.1785/0120190150.
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Abstract The capability to discriminate low‐magnitude earthquakes from low‐yield anthropogenic sources, both detectable only at local distances, is of increasing interest to the event monitoring community. We used a dataset of seismic events in Utah recorded during a 14‐day period (1–14 January 2011) by the University of Utah Seismic Stations network to perform a comparative study of event classification at local scale using amplitude ratio (AR) methods and a machine learning (ML) approach. The event catalog consists of 7377 events with magnitudes MC ranging from −2 and lower up to 5.8. Events were subdivided into six populations based on location and source type: tectonic earthquakes (TEs), mining‐induced events (MIEs), and mining blasts from four known mines (WMB, SMB, LMB, and CQB). The AR approach jointly exploits Pg‐to‐Sg phase ARs and Rg‐to‐Sg spectral ARs in multivariate quadratic discriminant functions and was able to classify 370 events with high signal quality from the three groups with sufficient size (TE, MIE, and SMB). For that subset of the events, the method achieved success rates between about 80% and 90%. The ML approach used trained convolutional neural network (CNN) models to classify the populations. The CNN approach was able to classify the subset of events with accuracies between about 91% and 98%. Because the neural network approach does not have a minimum signal quality requirement, we applied it to the entire event catalog, including the abundant extremely low-magnitude events, and achieved accuracies of about 94%–100%. We compare the AR and ML methodologies using a broad set of criteria and conclude that a major advantage to ML methods is their robustness to low signal‐to‐noise ratio data, allowing them to classify significantly smaller events.
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White, D. J., R. M. Easton, N. G. Culshaw, B. Milkereit, D. A. Forsyth, S. Carr, A. G. Green, and A. Davidson. "Seismic images of the Grenville Orogen in Ontario." Canadian Journal of Earth Sciences 31, no. 2 (February 1, 1994): 293–307. http://dx.doi.org/10.1139/e94-028.
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In 1990, Lithoprobe acquired 240 km of seismic-reflection data across parts of the Central Gneiss Belt (CGB) and the Central Metasedimentary Belt (CMB) within the western Grenville Province of southern Ontario. Interpretation of these data in conjunction with geological constraints provided by bedrock mapping supports a model of northwest-directed thrusting and crustal shortening for the Grenville Orogen. Within the CGB, the Parry Sound shear zone is imaged as a 3 km wide zone of reflections dipping southeastward at 20–25° and soling at depths < 7 km in the north and < 3 km in the south beneath Parry Sound domain. Parry Sound domain and the immediately adjacent domains are underlain by a gently southeast-dipping reflective zone at 4.5–12.0 km depth interpreted as a detachment surface, likely associated with the central Britt shear zone. This zone may have accommodated northwesterly transport of Parry Sound, southern Britt, and northwestern Rosseau domains over Britt domain during Grenvillian thrusting.Within the CMB, the seismic data indicate that crustal shortening and imbrication have not been confined to domain and terrane boundaries, as presently defined. A 6 km wide band of reflections dips south at ~20° from the surface within Bancroft terrane, soling into a mid-crustal décollement beneath Elzevir terrane. Beneath and to the north of this planar reflective zone is a complex pattern of strong, south-dipping (10–40°) reflections that extends from the near surface to the lower crust above a less reflective wedge-shaped zone. The zone of complex reflectivity projects updip to the CMB boundary zone and into the CGB; together with the linear band of reflections affiliated with Bancroft terrane, they form the tectonized boundary between the CGB and the CMB. To the south of the linear reflective zone, prominent reflective packages are restricted to the middle and upper crust. The generally nonreflective uppermost crust beneath Elzevir terrane is underlain by a series of gently southeast-dipping, antiformal reflections that appear to sole into the mid-crustal décollement beneath Mazinaw terrane. These observations suggest that the collision between the CMB and the CGB resulted in a sequence of relatively thin (15–20 km thick) allochthonous terranes within the CMB being transported along a regional décollement and thrust northwestward over footwall rocks of the CGB along a penetratively deformed tectonic zone, while a lower crustal wedge may have delaminated the CMB lower crust. Crustal thickness where defined by the seismic data is 42.0–43.5 km in both the CGB and the CMB.
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Lewis, Lisa A., Sanjay Ram, Alpana Prasad, Sunita Gulati, Silke Getzlaff, Anna M. Blom, Ulrich Vogel, and Peter A. Rice. "Defining Targets for Complement Components C4b and C3b on the Pathogenic Neisseriae." Infection and Immunity 76, no. 1 (November 5, 2007): 339–50. http://dx.doi.org/10.1128/iai.00613-07.
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ABSTRACT Complement is a key arm of the innate immune defenses against the pathogenic neisseriae. We previously identified lipooligosaccharide on Neisseria meningitidis as an acceptor for complement C4b. Little is known about other neisserial targets for complement proteins C3 and C4, which covalently attach to bacterial surfaces and initiate opsonization and killing. In this study we demonstrate that Neisseria gonorrhoeae porin (Por) 1B selectively binds C4b via amide linkages and C3b via ester linkages. Using strains expressing hybrid Por1A/1B molecules, a region spanned by loops 4 and 5 of Por1B was identified as the preferred binding site for C4b. We also identified the opacity protein (Opa), a major adhesin of pathogenic neisseriae, as a target for C4b and C3b on both N. meningitidis and N. gonorrhoeae. Using N. gonorrhoeae variants that predominantly expressed individual Opa proteins, we found that all Opa proteins tested (A, B, C, D, E, F, and I) bound C4b and C3b via amide and ester linkages, respectively. Amide linkages with Por1B and Opa were confirmed using serum containing only the C4A isoform, which exclusively forms amide linkages with targets. While monomers and heterodimers of C4Ab were detected on bacterial targets, C4Bb appeared to preferentially participate in heterodimer (C5 convertase) formation. Our data provide another explanation for the enhanced serum sensitivity of Por1B-bearing gonococci. The binding of C3b and C4b to Opa provides a rationale for the recovery of predominantly “transparent” (Opa-negative) neisserial isolates from persons with invasive disease, where the bacteria encounter high levels of complement.
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Rani, Richa, Manish Kumar Chatli, Mohan Jairath, Nitin Mehta, and Pavan Kumar. "Storage stability of functional chicken meat bullets coated with composite antimicrobial biodegradable films under different packaging conditions." Animal Production Science 56, no. 11 (2016): 1953. http://dx.doi.org/10.1071/an15107.
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Storage stability of processed chicken meat bullets (CMB) packaged under different packaging conditions in supplementation with composite antimicrobial biodegradable (CAB) films impregnated with 0.5% (v/v) cinnamaldehyde, a natural antimicrobial, was evaluated. Different treatments such as aerobic (aerobic packaged product, CAB-coated product and aerobic packaging), modified atmosphere packaging (MAP; MAP 50 : 50; CO2 and N2, F-MAP; CAB-coated product and MAP) and vacuum (VAC; vacuum packaged, F-VAC; CAB-coated product and vacuum) are assessed for various physico-chemical (pH, thiobarbituric acid reactive substances number, peroxide value and free fatty acids), microbiological (standard plate count, psychrophiles, coliforms, yeast and moulds, Staphylococci sp.) and sensory quality characteristics at 7-day intervals throughout the storage period of 35 days under refrigerated (4 ± 1°C) conditions. The CMB coated with CAB films under MAP (F-MAP) conditions had significantly (P < 0.05) better value for water activity, thiobarbituric acid reactive substances number, peroxide value and free fatty acids throughout the storage in comparison to the Control (MAP). Standard plate count was significantly (P < 0.05) lower for F-MAP than all other treatments. Staphylococci sp., coliforms, Salmonellae sp., yeast and mould, and psychrophiles were completely absent in CAB-coated products throughout the storage period. All the CAB products had better (P < 0.05) sensory attributes than their respective Controls during storage. Results concluded that the CMB coated in developed CAB films have a storage life of more than 35 days under MAP conditions under refrigerated (4 ± 1°C) conditions with the acceptable physico-chemical, microbiological and sensory quality attributes.
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Klickstein, L. B., T. J. Bartow, V. Miletic, L. D. Rabson, J. A. Smith, and D. T. Fearon. "Identification of distinct C3b and C4b recognition sites in the human C3b/C4b receptor (CR1, CD35) by deletion mutagenesis." Journal of Experimental Medicine 168, no. 5 (November 1, 1988): 1699–717. http://dx.doi.org/10.1084/jem.168.5.1699.
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Complementary DNA clones encoding the NH2-terminal region of human CR1 have been isolated and sequenced. The deduced complete amino acid sequence of the F allotype of human CR1 contains 2,039 residues, including a 41-residue signal peptide, an extracellular domain of 1,930 residues, a 25-amino acid transmembrane domain, and a 43-amino acid cytoplasmic region. The extracellular domain is composed exclusively of 30 short consensus repeats (SCRs), characteristic of the family of C3/C4-binding proteins. The 28 NH2-terminal SCRs are organized as four long homologous repeats (LHRs) of seven SCRs each. The newly sequenced LHR, LHR-A, is 61% identical to LHR-B in the NH2-terminal two SCRs and greater than 99% identical in the COOH-terminal five SCRs. Eight cDNA clones were spliced to form a single construct, piABCD, that contained the entire CR1 coding sequence downstream of a cytomegalovirus promoter. COS cells transfected with piABCD transiently expressed recombinant CR1 that comigrated with the F allotype of erythrocyte CR1 on SDS-PAGE and that mediated rosette formation with sheep erythrocytes bearing C4b and C3b. Recombinant CR1 also had factor I-cofactor activity for cleavage of C3(ma). Analyses of six deletion mutants expressed in COS cells indicated that the NH2-terminal two SCRs of LHR-A contained a site determining C4 specificity and the NH2-terminal two SCRs of LHR-B and -C each had a site determining C3 specificity. The presence of these three distinct sites in CR1 may enable the receptor to interact multivalently with C4b/C3b and C3b/C3b complexes generated during activation of the classical and alternative pathways.
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Murray, Hannah, Beiying Qiu, Sze Yuan Ho, and Xiaomeng Wang. "Complement Factor B Mediates Ocular Angiogenesis through Regulating the VEGF Signaling Pathway." International Journal of Molecular Sciences 22, no. 17 (September 3, 2021): 9580. http://dx.doi.org/10.3390/ijms22179580.
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Complement factor B (CFB), a 95-kDa protein, is a crucial catalytic element of the alternative pathway (AP) of complement. After binding of CFB to C3b, activation of the AP depends on the proteolytic cleavage of CFB by factor D to generate the C3 convertase (C3bBb). The C3 convertase contains the catalytic subunit of CFB (Bb), the enzymatic site for the cleavage of a new molecule of C3 into C3b. In addition to its role in activating the AP, CFB has been implicated in pathological ocular neovascularization, a common feature of several blinding eye diseases, however, with somewhat conflicting results. The focus of this study was to investigate the direct impact of CFB on ocular neovascularization in a tightly controlled environment. Using mouse models of laser-induced choroidal neovascularization (CNV) and oxygen-induced retinopathy (OIR), our study demonstrated an increase in CFB expression during pathological angiogenesis. Results from several in vitro and ex vivo functionality assays indicated a promoting effect of CFB in angiogenesis. Mechanistically, CFB exerts this pro-angiogenic effect by mediating the vascular endothelial growth factor (VEGF) signaling pathway. In summary, we demonstrate compelling evidence for the role of CFB in driving ocular angiogenesis in a VEGF-dependent manner. This work provides a framework for a more in-depth exploration of CFB-mediated effects in ocular angiogenesis in the future.
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Milanesi, Jovana de Moura, Priscila Weber, Luana Cristina Berwig, Rodrigo Agne Ritzel, Ana Maria Toniolo da Silva, and Eliane Castilhos Rodrigues Corrêa. "Childhood mouth-breathing consequences at adult age: ventilatory function and quality of life." Fisioterapia em Movimento 27, no. 2 (June 2014): 211–18. http://dx.doi.org/10.1590/0103-5150.027.002.ao06.
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Introduction Mouth breathing can affect the functions of the respiratory systems and quality of life. For this reason, children who grow up with this stimulus may have implications on physical and psychological aspects at adult age.Objective To evaluate childhood mouth-breathing consequences for the ventilatory function and quality of life at adult age.Materials and methods Prospective, observational and cross-sectional study with 24 adults, between 18 and 30 years old, mouth breathers during childhood, comprised the childhood mouth-breathing group (CMB). The childhood nasal-breathing (CNB) group was composed of 20 adults of the same age, without history of respiratory disease during all their lives. Measurements of maximal respiratory pressures, peak expiratory flow and 6-minute walk test were assessed. In addition, all the volunteers answered the Short Form-36 questionnaire (SF-36).Results The maximal inspiratory (p = 0.001) and expiratory (p = 0.000) pressures as well as the distance in the walk test (p = 0.003) were lower in the COB. The COB also presented lower score in the General Health domain of the SF-36 Questionnaire (p = 0.002).Conclusion Childhood mouth-breathing yields consequences for the ventilatory function at adult age, with lower respiratory muscle strength and functional exercise capacity. Conversely, the quality of life was little affected by the mouth breathing in this study.
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Fung, Ka Wai, David W. Wright, Jayesh Gor, Marcus J. Swann, and Stephen J. Perkins. "Domain structure of human complement C4b extends with increasing NaCl concentration: implications for its regulatory mechanism." Biochemical Journal 473, no. 23 (November 25, 2016): 4473–91. http://dx.doi.org/10.1042/bcj20160744.
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During the activation of complement C4 to C4b, the exposure of its thioester domain (TED) is crucial for the attachment of C4b to activator surfaces. In the C4b crystal structure, TED forms an Arg104–Glu1032 salt bridge to tether its neighbouring macroglobulin (MG1) domain. Here, we examined the C4b domain structure to test whether this salt bridge affects its conformation. Dual polarisation interferometry of C4b immobilised at a sensor surface showed that the maximum thickness of C4b increased by 0.46 nm with an increase in NaCl concentration from 50 to 175 mM NaCl. Analytical ultracentrifugation showed that the sedimentation coefficient s20,w of monomeric C4b of 8.41 S in 50 mM NaCl buffer decreased to 7.98 S in 137 mM NaCl buffer, indicating that C4b became more extended. Small angle X-ray scattering reported similar RG values of 4.89–4.90 nm for C4b in 137–250 mM NaCl. Atomistic scattering modelling of the C4b conformation showed that TED and the MG1 domain were separated by 4.7 nm in 137–250 mM NaCl and this is greater than that of 4.0 nm in the C4b crystal structure. Our data reveal that in low NaCl concentrations, both at surfaces and in solution, C4b forms compact TED–MG1 structures. In solution, physiologically relevant NaCl concentrations lead to the separation of the TED and MG1 domain, making C4b less capable of binding to its complement regulators. These conformational changes are similar to those seen previously for complement C3b, confirming the importance of this salt bridge for regulating both C4b and C3b.
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Tham, Wai-Hong, Christoph Q. Schmidt, Richard E. Hauhart, Mara Guariento, Patience B. Tetteh-Quarcoo, Sash Lopaticki, John P. Atkinson, Paul N. Barlow, and Alan F. Cowman. "Plasmodium falciparum uses a key functional site in complement receptor type-1 for invasion of human erythrocytes." Blood 118, no. 7 (August 18, 2011): 1923–33. http://dx.doi.org/10.1182/blood-2011-03-341305.
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AbstractThe Plasmodium falciparum adhesin PfRh4 binds to complement receptor type-1 (CR1) on human erythrocytes and mediates a glycophorin-independent invasion pathway. CR1 is a complement regulator and immune-adherence receptor on erythrocytes required for shuttling of C3b/C4b-opsonized particles to liver and spleen for phagocytosis. Using recombinant CR1 constructs, we mapped the recognition site for PfRh4 to complement control protein modules 1 to 3 (CCP1-3) at the membrane-distal amino terminus of CR1. This region of CR1 binds to C4b and C3b and accelerates decay of both classic pathway and alternative pathway C3 and C5 convertases. CCP1-3 competed for PfRh4 binding to erythroid CR1 and inhibited the PfRh4-CR1 invasion pathways across a wide range of P falciparum strains. PfRh4 did not bind significantly to other CR1 constructs, including CCP15-17, which is 85% identical to CCP1-3. PfRh4 binding to CR1 did not affect its C3b/C4b binding capability, and we show evidence for a ternary complex between CCP1-3, C4b, and PfRh4. PfRh4 binding specifically inhibited CR1's convertase decay-accelerating activity, whereas there was no effect on factor H-mediated decay-accelerating activity. These results increase our understanding of the functional implications of CR1 engagement with PfRh4 and highlight the interplay between complement regulation and infection.
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Mullick, Jayati, John Bernet, Yogesh Panse, Sharanabasava Hallihosur, Akhilesh K. Singh, and Arvind Sahu. "Identification of Complement Regulatory Domains in Vaccinia Virus Complement Control Protein." Journal of Virology 79, no. 19 (October 1, 2005): 12382–93. http://dx.doi.org/10.1128/jvi.79.19.12382-12393.2005.
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ABSTRACT Vaccinia virus encodes a homolog of the human complement regulators named vaccinia virus complement control protein (VCP). It is composed of four contiguous complement control protein (CCP) domains. Previously, VCP has been shown to bind to C3b and C4b and to inactivate the classical and alternative pathway C3 convertases by accelerating the decay of the classical pathway C3 convertase and (to a limited extent) the alternative pathway C3 convertase, as well as by supporting the factor I-mediated inactivation of C3b and C4b (the subunits of C3 convertases). In this study, we have mapped the CCP domains of VCP important for its cofactor activities, decay-accelerating activities, and binding to the target proteins by utilizing a series of deletion mutants. Our data indicate the following. (i) CCPs 1 to 3 are essential for cofactor activity for C3b and C4b; however, CCP 4 also contributes to the optimal activity. (ii) CCPs 1 to 2 are enough to mediate the classical pathway decay-accelerating activity but show very minimal activity, and all the four CCPs are necessary for its efficient activity. (iii) CCPs 2 to 4 mediate the alternative pathway decay-accelerating activity. (iv) CCPs 1 to 3 are required for binding to C3b and C4b, but the presence of CCP 4 enhances the affinity for both the target proteins. These results together demonstrate that the entire length of the protein is required for VCP's various functional activities and suggests why the four-domain structure of viral CCP is conserved in poxviruses.
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Derer, Stefanie, Thies Rösner, Stefan Lohse, Matthias Peipp, and Thomas Valerius. "Switching from IgG1 to IgG3 Isotype to Boost Complement-Activating Capacities of Therapeutic Antibodies – Impact of CD55 Expression on the Mode of Action." Blood 124, no. 21 (December 6, 2014): 3506. http://dx.doi.org/10.1182/blood.v124.21.3506.3506.
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Abstract Introduction: Complement-dependent cytotoxicity (CDC) against tumor cells is supposed to contribute to clinical efficacy of therapeutic CD20 antibodies of IgG1 isotype. However, some tumor-targeting antibodies such as cetuximab do not trigger CDC. Due to its prominent molecular flexibility and its longer hinge region human IgG3 gains advantage over human IgG1 in promoting activation of the complement system. Here, we investigated the cytotoxic activity of IgG3 isotype switch variants of the therapeutic antibodies rituximab (C2B8) and cetuximab (C225). Methods: CDC against tumor cells was assessed by 3 hours 51chromium release assays utilizing 25% v/v human serum. Antibody mediated deposition of C1q, C4b, C3b, factor Bb or C5b-9 on tumor cells as well as the release of anaphylatoxins C3a, C4a and C5a were analyzed by flow cytometry. Results: Both IgG1 and IgG3 variants of rituximab or cetuximab demonstrated similar efficiency in CD20 or EGFR binding, respectively. In the case of CD20 antibodies, C2B8-IgG3 induced stronger CDC against CD20 low-expressing cells, especially against freshly isolated CLL cells, than C2B8-IgG1, while no difference between both isotypes was detected against CD20 high-expressing cells. Importantly, CDC was also significantly triggered in an autologous setting against freshly isolated CLL cells by the IgG3 but not by the IgG1 version of rituximab. Furthermore, in the case of EGFR-targeting antibodies, only anti-EGFR-IgG3 but not anti-EGFR-IgG1 triggered significant CDC against some, but not all tested cell lines. CDC triggered by anti-EGFR-IgG3 negatively correlated with expression levels of the membrane-bound complement-regulatory proteins (mCRPs) CD55 and CD59, but not CD46. Notably, anti-EGFR-IgG3 promoted strong C1q and C3b but relatively low C4b and C5b-9 deposition on target cells. Furthermore, anti-EGFR-IgG3 triggered C4a release on all tested cell lines, but failed to induce C3a and C5a release on CD55/CD59 highly expressing cell lines. RNAi-induced knock-down or over-expression of mCRPs revealed CD55 expression to be a pivotal determinant of anti-EGFR-IgG3 triggered CDC and to force a switch from classical complement pathway activation to C1q-dependent alternative pathway amplification. Conclusions: In conclusion, an isotype switch from human IgG1 to human IgG3 is accompanied by improvement of complement activating capacities of CD20 as well as EGFR targeting antibodies. However, despite of its strong C1q fixing capacity, anti-EGFR-IgG3 lacks the ability to efficiently deposit C4b on targets’ cell surfaces and thus to initiate the complement cascade on CD55 high-expressing tumor cells. These novel findings revealed human IgG3 directed against CD20 or EGFR to encompass improved cytotoxic potential with low CD55 expression on tumor cells potentially being a promising biomarker for this novel approach. Disclosures No relevant conflicts of interest to declare.
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Tasiemski, Aurélie, Hamida Hammad, Franck Vandenbulcke, Christophe Breton, Thomas J. Bilfinger, Joel Pestel, and Michel Salzet. "Presence of chromogranin-derived antimicrobial peptides in plasma during coronary artery bypass surgery and evidence of an immune origin of these peptides." Blood 100, no. 2 (July 15, 2002): 553–59. http://dx.doi.org/10.1182/blood.v100.2.553.
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Abstract Chromogranin A (CGA) and chromogranin B (CGB) are acidic proteins stored in secretory organelles of endocrine cells and neurons. In addition to their roles as helper proteins in the packaging of peptides, they may serve as prohormones to generate biologically active peptides such as vasostatin-1 and secretolytin. These molecules derived from CGA and CGB, respectively, possess antimicrobial properties. The present study demonstrates that plasmatic levels of both vasostatin-1 and secretolytin increase during surgery in patients undergoing cardiopulmonary bypass (CPB). Vasostatin-1 and secretolytin, initially present in plasma at low levels, are released just after skin incision. Consequently, they can be added to enkelytin, an antibacterial peptide derived from proenkephalin A, for the panoply of components acting as a first protective barrier against hypothetical invasion of pathogens, which may occur during surgery. CGA and CGB, more commonly viewed as markers for endocrine and neuronal cells, were also found to have an immune origin. RNA messengers coding for CGB were amplified by reverse transcription–polymerase chain reaction in human monocytes, and immunocytochemical analysis by confocal microscopy revealed the presence of CGA or CGB or both in monocytes and neutrophils. A combination of techniques including confocal microscopic analysis, mass spectrometry measurement, and antibacterial tests allowed for the identification of the positive role of interleukin 6 (IL-6) in the secretolytin release from monocytes in vitro. Because IL-6 release is known to be strongly enhanced during CPB, we suggest a possible relationship between IL-6 and the increased level of secretolytin in patients undergoing CPB.
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Isaacs, Stuart N., Emelia Argyropoulos, Georgia Sfyroera, Shamim Mohammad, and John D. Lambris. "Restoration of Complement-Enhanced Neutralization of Vaccinia Virus Virions by Novel Monoclonal Antibodies Raised against the Vaccinia Virus Complement Control Protein." Journal of Virology 77, no. 15 (August 1, 2003): 8256–62. http://dx.doi.org/10.1128/jvi.77.15.8256-8262.2003.
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ABSTRACT The vaccinia virus complement control protein (VCP) is secreted by infected cells and has been shown to inhibit complement activation through interactions with C3b/C4b. It contains four short consensus repeat (SCR) domains. It has been suggested that all four SCRs are required for VCP's activity. To elucidate which SCR domains are involved in abolishing complement-enhanced neutralization of vaccinia virus virions, we generated and characterized a panel of mouse monoclonal antibodies (MAbs) raised against VCP. Ten MAbs were isolated and all recognized VCP on Western blots under reducing conditions as well as native-bound VCP in a sandwich enzyme-linked immunosorbent assay. Three of the 10 MAbs (2E5, 3D1, and 3F11) inhibited VCP's abolition of complement-enhanced neutralization of vaccinia virus virions. These MAbs blocked the interaction of VCP with C3b/C4b. The seven remaining MAbs did not alter VCP function in the complement neutralization assay and recognized VCP bound to C3b/C4b. To understand MAb specificity and mode of interaction with VCP, we mapped the MAb binding regions on VCP. The seven nonblocking MAbs all bound to the first SCR of VCP. One of the blocking MAbs recognized SCR 2 while the other two recognized either SCR 4 or the junction between SCRs 3 and 4, indicating that structural elements involved in the interaction of VCP with C3b/C4b are located within SCR domains 2 and 3 and 4. These anti-VCP MAbs may have clinical significance as therapeutic inhibitors of VCP's complement control activity and may also offer a novel approach to managing vaccinia virus vaccine complications that occur from smallpox vaccination.
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Johnson, John B., Ken Grant, and Griffith D. Parks. "The Paramyxoviruses Simian Virus 5 and Mumps Virus Recruit Host Cell CD46 To Evade Complement-Mediated Neutralization." Journal of Virology 83, no. 15 (May 20, 2009): 7602–11. http://dx.doi.org/10.1128/jvi.00713-09.
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ABSTRACT The complement system is a critical component of the innate immune response that all animal viruses must face during natural infections. Our previous results have shown that treatment of the paramyxovirus simian virus 5 (SV5) with human serum results in deposition of complement C3-derived polypeptides on virion particles. Here, we show that the virion-associated C3 component includes the inactive form iC3b, suggesting that SV5 may have mechanisms to evade the host complement system. Electron microscopy, gradient centrifugation, and Western blot analysis indicated that purified SV5 virions derived from human A549 cells contained CD46, a plasma membrane-expressed regulator of complement that acts as a cofactor for cleavage and inactivation of C3b into iC3b. In vitro cleavage assays with purified complement components showed that SV5 virions had C3b cofactor activity, resulting in specific factor I-mediated cleavage of C3b into inactive iC3b. SV5 particles generated in CHO cells, which do not express CD46, did not have cofactor activity. Conversely, virions derived from a CHO cell line that was engineered to overexpress human CD46 contained elevated levels of virion-associated CD46 and displayed enhanced C3b cofactor activity. In comparison with C3b, purified SV5 virions had very low cofactor activity against C4b, consistent with the known preference of CD46 for C3b versus C4b. Similar results were obtained for the closely related mumps virus (MuV), except that MuV particles derived from CHO-CD46 cells had higher C4b cofactor activity than SV5 virions. In neutralization assays with human serum, SV5 and MuV containing CD46 showed slower kinetics and more resistance to neutralization than SV5 and MuV that lacked CD46. Our results support a model in which the rubulaviruses SV5 and MuV incorporate cell surface complement inhibitors into progeny virions as a mechanism to limit complement-mediated neutralization.
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Singh, Akhilesh K., Viveka Nand Yadav, Kalyani Pyaram, Jayati Mullick, and Arvind Sahu. "Mapping of Functional Domains in Herpesvirus Saimiri Complement Control Protein Homolog: Complement Control Protein Domain 2 Is the Smallest Structural Unit Displaying Cofactor and Decay-Accelerating Activities." Journal of Virology 83, no. 19 (July 29, 2009): 10299–304. http://dx.doi.org/10.1128/jvi.00217-09.
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ABSTRACT Herpesvirus saimiri encodes a functional homolog of human regulator-of-complement-activation proteins named CCPH that inactivates complement by accelerating the decay of C3 convertases and by serving as a cofactor in factor I-mediated inactivation of their subunits C3b and C4b. Here, we map the functional domains of CCPH. We demonstrate that short consensus repeat 2 (SCR2) is the minimum domain essential for classical/lectin pathway C3 convertase decay-accelerating activity as well as for factor I cofactor activity for C3b and C4b. Thus, CCPH is the first example wherein a single SCR domain has been shown to display complement regulatory functions.
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Seya, T., J. R. Turner, and J. P. Atkinson. "Purification and characterization of a membrane protein (gp45-70) that is a cofactor for cleavage of C3b and C4b." Journal of Experimental Medicine 163, no. 4 (April 1, 1986): 837–55. http://dx.doi.org/10.1084/jem.163.4.837.
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Based on preliminary evidence indicating that a cell-associated protein of U937 (a human monocyte-like cell line) possessed cofactor activity and was not the C3b/C4b receptor, we sought to further characterize this protein. A sequential four-column purification procedure was devised that includes C3(H2O) affinity chromatography to isolate in reasonable yields and purity a cell-associated protein of U937 and several other human cell lines. Based on its pattern and Mr on SDS-PAGE, acidic pI, and ligand specificity, it is identical to a recently described C3(H2O) or C3b-binding membrane glycoprotein of human PBL and cell lines; having no presently identified function, it was termed gp45-70. After purifying this protein, we determined its functional capabilities and compared them to those of the other complement proteins with regulatory activity directed at components comprising the C3 convertases. This protein was the most efficient (50 times that of H) yet-described cofactor for the I-mediated first cleavage of C3b. It also was a cofactor for the first cleavage of C4b, but was not as efficient as C4bp. The second cleavage of C3b and C4b was not efficiently mediated. It had no ability to accelerate decay in the classical or alternative pathway C3 convertases. Based on this unique activity profile and ability to be surface labeled, we have renamed this molecule membrane cofactor protein (MCP). We suggest that this protein plays a major role in preventing autologous complement activation.
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Frasquet-Deltoro, Marta, María-del-Carmen Alarcón-del-Amo, and Carlota Lorenzo-Romero. "Antecedents and consequences of virtual customer co-creation behaviours." Internet Research 29, no. 1 (February 4, 2019): 218–44. http://dx.doi.org/10.1108/intr-06-2017-0243.
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Purpose The purpose of this paper is to compare the antecedents and consequences of two distinct types of virtual co-creation behaviours that require different degree of effort from the customer, i.e. customer participation (CPB), and customer citizenship (CCB) behaviour, in a cross-cultural study. Design/methodology/approach A survey was conducted among members of online panels in the UK and Spain, reaching a sample of 800 online individuals who participate in online co-creation processes with fashion retailers. This design allows us to test the cross-cultural effects. Multi-group structural equations modelling was used to analyse the data. Findings Virtual co-creation behaviours are driven by perceived ease-of-use of the co-creation platform, electronic word-of-mouth (e-WOM) quality and fashion involvement; however, the effects are different on CPB, affected by perceived ease-of-use more strongly, and on CCB, driven by e-WOM quality and fashion involvement more strongly. Higher level of co-creation increases satisfaction with co-creation, which mediates the effect on engagement and intention of future co-creation. The cross-cultural design reveals that most relationships hold in both countries, with the exception of the influence of fashion involvement on CPB, while some differences in the size of the effects appear between countries. Originality/value This study contributes to increasing our knowledge on online co-creation in several ways. First, the authors investigate, in the online environment, two co-creation behaviours, CPB and CCB, and compare their antecedents. This paper provides a cross-cultural validation of the relationships between CPB and CCB’s antecedents and consequences, identifying the different effects due to culture.
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Quagliarini, Enrico, and Gianluca Maracchini. "Experimental and FEM Investigation of Cob Walls under Compression." Advances in Civil Engineering 2018 (August 27, 2018): 1–13. http://dx.doi.org/10.1155/2018/7027432.
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Earth has been used as construction material since prehistoric times, and it is still utilized nowadays in both developed and developing countries. Heritage conservation purposes and its intrinsic environmental benefits have led researchers to investigate the mechanical behaviour of this material. However, while a lot of works concern with rammed earth, CEB, and adobe techniques, very few studies are directed towards cob, which is an alternative to the more diffused rammed earth and adobe in specific geographic conditions. Due to this lack, this paper presents an experimental program aimed at assessing the failure mode and the main mechanical properties of cob earth walls (compressive strength, Young’s modulus, and Poisson’s ratio) through monotonic axial compression tests. Results show that, if compared with CEB, adobe, and rammed earth, cob has the lowest compressive strength, the lowest modulus of elasticity, and Poisson’s ratio. Differences are also found by comparing results with those obtained for other cob techniques, underlining both the high regional variability of cob and the need of performing more research on this topic. A strong dependence of material properties on loading rate and water content seems to exist too. Finally, the ability of a common analytical method used for masonry structures (an FEM macromodelling with a total strain rotating crack model) to represent the mechanical behaviour of cob walls is showed.
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Fröschen, Frank Sebastian, Sophia Schell, Matthias Dominik Wimmer, Gunnar Thorben Rembert Hischebeth, Hendrik Kohlhof, Sascha Gravius, and Thomas Martin Randau. "Synovial Complement Factors in Patients with Periprosthetic Joint Infection after Undergoing Revision Arthroplasty of the Hip or Knee Joint." Diagnostics 11, no. 3 (March 4, 2021): 434. http://dx.doi.org/10.3390/diagnostics11030434.
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The role and diagnostic value of the synovial complement system in patients with low-grade periprosthetic joint infection (PJI) are unclear. We sought to evaluate, for the first time, the usefulness of synovial complement factors in these patients by measuring the individual synovial fluid levels of complement factors (C1q, C3b/iC3b, C4b, C5, C5a, C9, factor B, factor D, factor H, factor I, properdin, and mannose-binding lectin [MBL]). The patients (n = 74) were classified into septic (n = 28) and aseptic (n = 46). Receiver-operator characteristic curves and a multiple regression model to determine the feasibility of a combination of the tested cytokines to determine the infection status were calculated. The synovial fluid levels of C1q, C3b/C3i, C4b, C5, C5a, MBL, and properdin were significantly elevated in the PJI group. The best sensitivity and specificity was found for C1q. The multiple regression models revealed that the combination of C1q, C3b/C3i, C4b, C5, C5a, and MBL was associated with the best sensitivity (83.3%) and specificity (79.2%) for a cutoff value of 0.62 (likelihood ratio: 4.0; area under the curve: 0.853). Nevertheless, only a combined model showed acceptable results. The expression patterns of the complement factors suggested that PJI activates all three pathways of the complement system.
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Han, Yue, Jie Wang, Jia Chen, Jiaqian Qi, Jian Su, Zhenni Ma, Yaqiong Tang, et al. "Alterations of Plasma Complement C3b, C5b and VWF, ADAMTS13 in Patients with Graft-Versus-Host Disease and Thrombotic Microangiopathy after Hematopoietic Stem-Cell Transplantation." Blood 126, no. 23 (December 3, 2015): 3143. http://dx.doi.org/10.1182/blood.v126.23.3143.3143.
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Abstract Background: Transplant-associated microangiopathy (TMA) is an uncommon but devastating complication in patients undergoing hematopoietic stem-cell transplantation (HSCT). It may be confused with severe graft-versus-host disease (GVHD), infection, and other transplant related thrombotic diseases. Limited studies have shown the changes in plasma VWF/ADAMTS13 or complement activation markers in patients after HSCT. However, the role of VWF/ADAMTS13 and complement activation in patients with TMA and GVHD is not fully understood. Current study is to investigate the alterations of plasma levels of C3b, C5b and VWF/ADAMTS13 in patients with TMA and to explore their roles in the pathogenesis and early diagnosis of transplant-associated TMA. Methods: From 2011 to 2014, 14 patients with TMA were enrolled into the study in a single medical center. 71 other patients following HSCT were recruited as control subjects including 11 cases of hepatic vein occlusion disease (VOD), 20 cases of severe infections, 20 cases of severe II-IV° GVHD and 20 cases without complications. Blood sample was collected before transplantation and at the onset of transplantation related complication. Fluorescence resonance energy transfer substrate (FRETS)-VWF73 assay detected plasma ADAMTS13 activity. Collagen-binding assay and latex immunoassay determined VWF activity and VWF antigen, respectively. Plasma VWF multimer was determined by agarose gel electrophoresis and Western blot. Plasma levels of complement C3b and C5b were measured with ELISA. Results: Compared with the levels before transplantation, plasma ADAMTS13 activity and VWF antigen or activity in the patients with TMA did not differ from those who developed TMA, with infection or GVHD or without any complication (p> 0.05). However, plasma ADAMTS13 activity decreased and the ratio of VWF antigen/activity increased significantly in patients with VOD (p< 0.05). Plasma VWF multimer distribution was similar in patients with infection, GVHD or without complication, but ultralarge multimers of VWF was present in patients with TMA and VOD. Plasma levels of complement C3b was increased in patients after HSCT (198.46 ng/ml ±14.78 ng/ml) compared with healthy subjects (85.02 ng/ml±8.50ng/ml) (p< 0.05), but exhibited no difference in the other groups. Plasma C3b increased significantly in patients with TMA and GVHD (p<0.05). The plasma levels of C3b were higher in the TMA group (480.70 ng/ml±66.76ng/ml) than the GVHD group (298.50 ng/ml ±32.06 ng/) (p< 0.05). Also, plasma levels of C5b in patients with TMA were significantly increased (1059.49 ng/ml ±85.57 ng/ml) as compared with those before transplantation (653.19ng/ml ±44.91ng/ml) and other groups (p< 0.05). Conclusions: We conclude that plasma ADAMTS 13 activity and the ratio of VWF antigen/activity remained stable in the patients with transplant-associated TMA, but the levels of complement C3b and C5b, particularly the C5b, increased significantly, suggesting the critical role of complement pathway in the pathogenesis of TMA. C5b may be a specific biomarker for early diagnosis of TMA but C3b is a marker for both TMA and GVHD. Disclosures No relevant conflicts of interest to declare.
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Garreto, Valdrickson Costa, Amália Santos da Silva, Misael Batista Farias Araújo, Larissa Ramos dos Santos, Hosana Aguiar Freitas de Andrade, Analya Roberta Fernandes Oliveira, and Raissa Rachel Salustriano da Silva-Matos. "Produção de mudas de árvore-da-felicidade (Polyscias spp.) sob concentrações de caule decomposto de babaçu." Research, Society and Development 9, no. 7 (June 8, 2020): e737974076. http://dx.doi.org/10.33448/rsd-v9i7.4076.
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A árvore-da-felicidade (Polyscias spp.) é um arbusto pertencente à família Araliaceae. Objetivou-se avaliar o caule decomposto de babaçu (CDB) como substrato na propagação vegetativa da árvore-da-felicidade. O experimento foi realizado em casa de vegetação com 70% de luminosidade, de agosto a setembro de 2018, no Centro de Ciências Agrárias e Ambientais (CCAA) da Universidade Federal do Maranhão (UFMA). Adotou-se o delineamento inteiramente casualizado com seis tratamentos compostos por CDB, nas seguintes proporções: 0%, 20%, 40%, 60%, 80%, e 100% de CDB, acrescidas de solo, constituído de 4 repetições, cada repetição continha 3 unidades, totalizando 12 unidades experimentais por parcela. As variáveis analisadas foram: porcentagem de sobrevivência das estacas (PS); número de brotos (NB); área foliar (AF); comprimento do maior broto (CMB); diâmetro do maior broto (DMB); comprimento radicular (CR); volume de raiz (VR); e massa seca do sistema radicular (MSSR). Obteve-se efeito significativo (p<0,01) para DMB e CR, e (p<0,05) para CMB e MSPA, entretanto, não houve diferença significativa no NB, PS, AF, MSSR e VR. O CDB pode ser utilizado como substrato na propagação vegetativa de árvore-da-felicidade.
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Maniyar, A., G. Lagache, M. Béthermin, and S. Ilić. "Constraining cosmology with the cosmic microwave and infrared backgrounds correlation." Astronomy & Astrophysics 621 (January 2019): A32. http://dx.doi.org/10.1051/0004-6361/201833765.
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We explore the use of the cosmic infrared background (CIB) as a tracer of the large scale structures for cross-correlating with the cosmic microwave background (CMB) and exploit the integrated Sachs–Wolfe (ISW) effect. We used an improved linear CIB model from our previous work and derived the theoretical CIB×ISW cross-correlation for different Planck HFI frequencies (217, 353, 545 and 857 GHz) and IRAS (3000 GHz). As expected, we predict a positive cross-correlation between the CIB and the CMB whose amplitude decreases rapidly at small scales. We perform a signal-to-noise ratio (S/N) analysis of the predicted cross-correlation. In the ideal case when the cross-correlation is obtained over 70% (40%) of the sky without residual contaminants (e.g. galactic dust) in maps, the S/N ranges from 4.2 to 5.6 (3.2 to 4.3); the highest S/N comes from 857 GHz. A Fisher matrix analysis shows that an ISW signal detected with a S/N this high on the 40% sky can considerably improve the constraints on the cosmological parameters; constraints on the equation of state of the dark energy especially are improved by 80%. We then performed a more realistic analysis considering the effect of residual galactic dust contamination in CIB maps. We calculated the dust power spectra for different frequencies and sky fractions that dominate the CIB power spectra at the lower multipoles we are interested in. Considering a conservative 10% residual level of galactic dust in the CIB power spectra, we observe that the S/N drops drastically, which makes it very challenging to detect the ISW. To determine the capability of current maps to detect the ISW effect through this method, we measured the cross-correlation of the CIB and the CMB Planck maps on the so-called GASS field, which covers an area of ∼11% in the southern hemisphere. We find that with such a small sky fraction and the dust residuals in the CIB maps, we do not detect any ISW signal, and the measured cross-correlation is consistent with zero. To avoid degrading the S/N for the ISW measurement by more than 10% on the 40% sky, we find that the dust needs to be cleaned up to the 0.01% level on the power spectrum.
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Reilly, B. D., S. C. Makrides, P. J. Ford, H. C. Marsh, and C. Mold. "Quantitative analysis of C4b dimer binding to distinct sites on the C3b/C4b receptor (CR1)." Journal of Biological Chemistry 269, no. 10 (March 1994): 7696–701. http://dx.doi.org/10.1016/s0021-9258(17)37343-x.
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Kinoshita, T., M. E. Medof, K. Hong, and V. Nussenzweig. "Membrane-bound C4b interacts endogenously with complement receptor CR1 of human red cells." Journal of Experimental Medicine 164, no. 5 (November 1, 1986): 1377–88. http://dx.doi.org/10.1084/jem.164.5.1377.
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Activation of the classical complement pathway on the membrane of autologous cells results in the deposition of C4b on their surface and in the assembly of the C3 convertase C4b2a, one of the amplifying enzymes of the cascade. Here we study the sequence of events leading to irreversible inactivation of the potentially harmful C4b bound to human red cells. We show that deposited C4b interacts endogenously with complement receptor type 1 (CR1) present on the membrane of the same red cell. Complexes containing CR1 and C4b are found in extracts of membranes of C4b-bearing red cells after treatment of the intact cells with a bifunctional crosslinking reagent. The amount of complexed CR1 increases with the number of deposited C4b molecules. Only small amounts of free CR1 are observed on red cells bearing as few as 1,900 molecules of C4b, suggesting that the binding avidity between C4b and endogenous CR1 is high. In agreement with this observation, we find that the deposited C4b inhibits the exogenous cofactor activity of the red cell CR1 for the factor I-mediated cleavage of target-bound clustered C3b. The C4b bound to the human red cells is cleaved by the serum enzyme C3b/C4b inactivator (factor I) and a large fragment (C4c) is released in the incubation medium. The cleavage is totally inhibited by mAbs against CR1, showing that the complement receptor is an essential cofactor for the activity of I. When the number of bound C4b per red cell is relatively small (less than 1,000 molecules) the substrate for the enzymatic activity of factor I is mostly or exclusively the C4b bound endogenously to CR1. Indeed, the kinetics or the extent of cleavage of C4b are not affected by greatly augmenting the concentration of exogenous CR1 or of C4b-bearing red cells in the incubation mixture, thereby increasing the frequency of collisions between CR1 on the surface of one cell with C4b deposited on the membrane of a different cell. On the basis of the present and prior observations, we speculate that both DAF and CR1 act endogenously to inactivate the function of autologous red cell-bound C4b and prevent the progression of the cascade. DAF binding prevents the formation of the C3 convertase, C4b2a. The cleavage and irreversible inactivation of C4b only occurs after the concerted activities of endogenous CR1 and serum factor I.(ABSTRACT TRUNCATED AT 400 WORDS)
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Zhang, Shihai, Shouyong Wang, and Shanglong Yao. "Evidence for Development of Capillary Leak Syndrome Associated with Cardiopulmonary Bypass in Pediatric Patients with the Homozygous C4A Null Phenotype." Anesthesiology 100, no. 6 (June 1, 2004): 1387–93. http://dx.doi.org/10.1097/00000542-200406000-00009.
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Background The mechanism of postoperative capillary leak syndrome related to cardiopulmonary bypass (CPB) is unknown. The authors hypothesized that C4 gene polymorphism might be involved in the development of the syndrome because complement activation is associated with CPB and protamine administration, and the two isotypes of C4 (C4A and C4B) differ in their biochemical and functional properties after activation. Methods One hundred fifty-six pediatric patients referred for elective cardiac surgery with CPB were included in the study. C4 isotype studies were performed in plasma samples obtained before surgery, with use of agarose gel immunofixation and crossed immunoelectrophoresis. Five possible C4 phenotype groups were observed, which were abbreviated as follows: (1) AABB = no detectable null alleles, (2) A0BB = a single null allele (heterozygous) at the C4A locus, (3) 00BB = a homozygous C4A null allele, (4) AAB0 = a single null allele (heterozygous) at the C4B locus, and (5) AA00 = a homozygous C4B null allele. The patients were classified into five groups according to their C4 phenotypes. Before CPB and at 1 h after CPB, plasma protein was measured with a biuret test kit. Plasma colloid osmotic pressure was determined with a membrane osmometer. Evans blue dye was used to measure plasma volume, serum protein, intravenous protein pool, and transvascular escape rate of Evans blue dye. Results Of 156 pediatric patients enrolled, 80 were assigned to the AABB group, 28 were assigned to the A0BB group, 7 were assigned to the 00BB group, 31 were assigned to the AAB0 group, and 10 were assigned to the AA00 group, according to their C4 phenotypes. At 1 h after CPB, serum protein concentrations averaged 3.6 +/- 0.4 g/dl in patients with the 00BB C4 phenotype; this value was significantly lower (P < 0.01) than that in patients with other C4 phenotypes. The changes of intravenous protein pool and colloid osmotic pressure were comparable with the change in serum protein concentration. At 1 h after CPB, the transvascular escape rate of Evans blue dye averaged 11.5 +/- 1.3%/h in patients with the 00BB C4 phenotype; this value was significantly higher (P < 0.01) than that in patients with other C4 phenotypes. Conclusions In this study, capillary leak syndrome induced by CPB occurred only in patients with the homozygous C4A null phenotype.
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Ramlawi, Basel, Kareem Bedeir, Luis Garcia-Morales, Limael Rodriguez, Michael Reardon, and Mahesh Ramchandani. "Improved Short-Term Outcomes with Off-Pump Reoperative Coronary Artery Bypass Grafting." Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery 9, no. 1 (January 2014): 49–53. http://dx.doi.org/10.1097/imi.0000000000000031.
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Objective Reoperative coronary surgery patients are usually sicker and older, and the procedure is more technically demanding. Comparisons between coronary surgery with (coronary artery bypass [CAB] surgery on cardiopulmonary bypass [CPB]) and without (off-pump CAB [OPCAB]) the pump have been conducted; however, few studies showed results in reoperative cases. We investigate the potential superiority of one technique over the other in redo coronary surgeries. Methods Our institutional Society of Thoracic Surgery database was used to gather the data for 266 isolated reoperative coronary artery surgeries from January 2004 to July 2011. These were divided into the CAB surgery in CPB group (n = 204) and the OPCAB group (n = 62). Results Baseline characteristics of the two groups were similar, except for a significantly higher prevalence of cerebrovascular disease among the off-pump group ( P = 0.01). There was also a trend toward fewer vessels bypassed among the same group ( P = 0.07). Risk adjustment was done using multivariable analyses for detection of independent effects. The use of CPB was an independent predictor of increased rates of postoperative events (odds ratio, 3.9; P = 0.004) and atrial fibrillation (odds ratio, 5.9; P < 0.005) and longer intensive care unit (0.006) and hospital stay (0.004). Conclusions Redo OPCAB seems to offer favorable short-term outcomes compared with redo CAB. Our results suggest a reduced rate of overall postoperative events, decreased new postoperative atrial fibrillation, reduced hours stayed in the intensive care unit, and fewer days stayed from surgery to discharge. This was not associated with an increase in morbidity and mortality. A randomized study with a larger number of patients and with a longer follow-up is needed.
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Vedeler, C. A., N. E. Gilhus, and R. Matre. "Erythrocyte C3b/C4b Receptors (CR1) in Patients with Myasthenia Gravis." Autoimmunity 6, no. 3 (January 1990): 235–36. http://dx.doi.org/10.3109/08916939009041043.
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Kwon, So Hyun, Jung Eun Park, Yeong Hee Cho, and Jung Sup Lee. "Effect of Vibrio-Derived Extracellular Protease vEP-45 on the Blood Complement System." Biology 10, no. 8 (August 18, 2021): 798. http://dx.doi.org/10.3390/biology10080798.
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Vibrio vulnificus is a pathogenic bacterium that can causes wound infections and fetal septicemia. We have reported that V. vulnificus ATCC29307 produces an extracellular zinc-metalloprotease (named vEP-45). Our previous results showed that vEP-45 can convert prothrombin to active thrombin and also activate the plasma kallikrein/kinin system. In this study, the effect of vEP-45 on the activation of the complement system was examined. We found that vEP-45 could proteolytically convert the key complement precursor molecules, including C3, C4, and C5, to their corresponding active forms (e.g., C3a, C3b, C4a, C4b, and C5a) in vitro cleavage assays. C5b production from C5 cleavage mediated by vEP-45 was not observed, whereas the level of C5a was increased in a dose-dependent manner compared to that of the non-treated control. The cleavage of the complement proteins in human plasma by vEP-45 was also confirmed via Western blotting. Furthermore, vEP-45 could convert C3 and C5 to active C3a and C5a as a proinflammatory mediator, while no cleavage of C4 was observed. These results suggest that vEP-45 can activate the complement system involved in innate immunity through an alternative pathway.
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Fischer, Peter M., Teresa Bürge, Jacek Tracz, and Dominika Kofel. "The New Swedish Cyprus Expedition 2018: Excavations at Hala Sultan Tekke (The Söderberg Expedition). Preliminary results, with contributions by J. Tracz and D. Kofel." Opuscula. Annual of the Swedish Institutes at Athens and Rome, no. 12 (November 2019): 287–326. http://dx.doi.org/10.30549/opathrom-12-10.
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During the ninth field season at the Late Bronze Age city of Hala Sultan Tekke, excavations in City Quarter 1 (CQ1) continued and brought to light industrial and domestic structures belonging to three phases of occupation (Strata 3–1) dating to the 13th and 12th centuries BC (LC IIC–IIIA). Finds of more than half a ton of copper slag together with remains of furnaces and tuyères indicate intensive urban copper production. There is also evidence of textile production in CQ1. A magnetometer survey of roughly 23 ha resulted in the discovery of another large city quarter (CQ4) between CQ1 and Area A (the cemetery) with regularly arranged stone-built compounds of imposing dimensions intersected by streets. Several massive walls are faced with ashlar slabs which distinguishes this quarter from the industrial and domestic CQ1–3. A bathroom built of ashlar blocks with an advanced hydrological layout was exposed in CQ4 (Stratum 1, LC IIIA) together with a storage area for large vessels. Another rich tomb (Tomb RR) was excavated in Area A. It contained multi-burials together with tomb gifts from numerous Eastern Mediterranean cultures. One of the finds from Tomb RR is a complete large Mycenaean krater depicting two chariots drawn by two pairs of horses and 13 individuals, several of them with swords.
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Aussel, Hervé. "Results from ISOCAM Deep Surveys: An Answer on the AGN Contribution to the Cosmic Infrared Background." International Astronomical Union Colloquium 184 (2002): 179–88. http://dx.doi.org/10.1017/s0252921100030669.
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AbstractThe amount of energy contributed by type-2 AGNs to the Cosmic Infrared Background (CIB) has recently been the subject of some debate, since models have shown it could be responsible for up to half. If this were the case, this contribution should be taken carefully into account before using the combined CIB and COB to derive the density of metals in the universe. I argue here that an observational answer to this problem comes from ISOCAM deep surveys performed at 15 μm, that do resolve into discrete sources the bulk of the CIB at 140 μm. Studies of the X-ray properties of these sources allow us to assess whether or not they are dominated by AGNs, and to derive that the type-2 AGNs contribution to the CIB is not greater than 20%.
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Meseda, Clement A., Jordan Kuhn, Vajini Atukorale, Joseph Campbell, and Jerry P. Weir. "Glycosylated and Nonglycosylated Complement Control Protein of the Lister Strain of Vaccinia Virus." Clinical and Vaccine Immunology 21, no. 9 (July 16, 2014): 1330–38. http://dx.doi.org/10.1128/cvi.00347-14.
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ABSTRACTThe vaccinia virus complement control protein (VCP) is a secreted viral protein that binds the C3b and C4b complement components and inhibits the classic and alternative complement pathways. Previously, we reported that an attenuated smallpox vaccine, LC16m8, which was derived from the Lister strain of vaccinia virus (VV-Lister), expressed a glycosylated form of VCP, whereas published sequence data at that time indicated that the VV-Lister VCP has no motif for N-linked glycosylation. We were interested in determining whether the glycosylation of VCP impairs its biological activity, possibly contributing to the attenuation of LC16m8, and the likely origin of the glycosylated VCP. Expression analysis indicated that VV-Lister contains substrains expressing glycosylated VCP and substrains expressing nonglycosylated VCP. Other strains of smallpox vaccine, as well as laboratory strains of vaccinia virus, all expressed nonglycosylated VCP. Individual Lister virus clones expressing either the glycosylated VCP or the nonglycosylated species were isolated, and partially purified VCP from the isolates were found to be functional equivalents in binding human C3b and C4b complement proteins and inhibiting hemolysis and in immunogenicity. Recombinant vaccinia viruses expressing FLAG-tagged glycosylated VCP (FLAG-VCPg) and nonglycosylated VCP (FLAG-VCP) were constructed based on the Western Reserve strain. Purified FLAG-VCP and FLAG-VCPg bind human C3b and C4b and blocked complement-mediated hemolysis. Our data suggest that glycosylation did not affect the biological activity of VCP and thus may not have contributed to the attenuation of LC16m8. In addition, the LC16m8 virus likely originated from a substrain of VV-Lister that expresses glycosylated VCP.
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Spiller, O. B., L. Mark, C. E. Blue, D. G. Proctor, J. A. Aitken, A. M. Blom, and D. J. Blackbourn. "Dissecting the Regions of Virion-Associated Kaposi's Sarcoma-Associated Herpesvirus Complement Control Protein Required for Complement Regulation and Cell Binding." Journal of Virology 80, no. 8 (April 15, 2006): 4068–78. http://dx.doi.org/10.1128/jvi.80.8.4068-4078.2006.
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ABSTRACT Complement, which bridges innate and adaptive immune responses as well as humoral and cell-mediated immunity, is antiviral. Kaposi's sarcoma-associated herpesvirus (KSHV) encodes a lytic cycle protein called KSHV complement control protein (KCP) that inhibits activation of the complement cascade. It does so by regulating C3 convertases, accelerating their decay, and acting as a cofactor for factor I degradation of C4b and C3b, two components of the C3 and C5 convertases. These complement regulatory activities require the short consensus repeat (SCR) motifs, of which KCP has four (SCRs 1 to 4). We found that in addition to KCP being expressed on the surfaces of experimentally infected endothelial cells, it is associated with the envelope of purified KSHV virions, potentially protecting them from complement-mediated immunity. Furthermore, recombinant KCP binds heparin, an analogue of the known KSHV cell attachment receptor heparan sulfate, facilitating infection. Treating virus with an anti-KCP monoclonal antibody (MAb), BSF8, inhibited KSHV infection of cells by 35%. Epitope mapping of MAb BSF8 revealed that it binds within SCR domains 1 and 2, also the region of the protein involved in heparin binding. This MAb strongly inhibited classical C3 convertase decay acceleration by KCP and cofactor activity for C4b cleavage but not C3b cleavage. Our data suggest similar topological requirements for cell binding by KSHV, heparin binding, and regulation of C4b-containing C3 convertases but not for factor I-mediated cleavage of C3b. Importantly, they suggest KCP confers at least two functions on the virion: cell binding with concomitant infection and immune evasion.
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Joiner, K. A., L. F. Fries, M. A. Schmetz, and M. M. Frank. "IgG bearing covalently bound C3b has enhanced bactericidal activity for Escherichia coli 0111." Journal of Experimental Medicine 162, no. 3 (September 1, 1985): 877–89. http://dx.doi.org/10.1084/jem.162.3.877.
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The mechanism was sought by which bactericidal IgG for E. coli 0111 (strain 12015) increases the bactericidal efficiency of C5b-9. IgG did not affect the distribution of C3 deposition on the O-Ag capsule and the outer membrane of 12015, suggesting that bactericidal IgG was not directing complement activation to different sites on the bacterial surface. However, one-fifth of the C3 that was deposited in the presence of IgG attached covalently to the antibody molecule. Covalent complexes between purified C3b and IgG were prepared in order to study the role of C3b-IgG in the bactericidal reaction. 8-10-fold less C3b-IgG than IgG was necessary to sensitize 12015 for serum killing. When aggregates were eliminated from the C3b-IgG and IgG preparations by sucrose density gradient ultracentrifugation, C3b-IgG remained three- to fourfold more effective than IgG on a molecule-for-molecule bound basis in mediating the serum bactericidal reaction. These results suggest that formation of C3b-IgG during the serum bactericidal reaction is critical for killing, and have important implications for the development of effective bactericidal vaccines.
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White, Kendra D., Mark Barton Frank, Stephen Foundling, and Frank J. Waxman. "Effect of immunoglobulin variable region structure on C3b and C4b deposition." Molecular Immunology 33, no. 9 (June 1996): 759–68. http://dx.doi.org/10.1016/0161-5890(96)00031-4.
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Holers, V. Michael, Joe L. Cole, Douglas M. Lublin, Tsukasa Seya, and John P. Atkinson. "Human C3b- and C4b-regulatory proteins: a new multi-gene family." Immunology Today 6, no. 6 (June 1985): 188–92. http://dx.doi.org/10.1016/0167-5699(85)90114-8.
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