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Sample records for activatable fibrinolysis inhibitor

  1. Thrombin-activatable fibrinolysis inhibitor.

    PubMed

    Marx, Pauline F

    2004-09-01

    The coagulation system is a potent mechanism that prevents blood loss after vascular injury. It consists of a number of linked enzymatic reactions resulting in thrombin generation. Thrombin converts soluble fibrinogen into a fibrin clot. The clot is subsequently removed by the fibrinolytic system upon wound healing. Thrombin-activatable fibrinolysis inhibitor (TAFI), which is identical to the previously identified proteins procarboxypeptidase B, R, and U, forms a link between blood coagulation and fibrinolysis. TAFI circulates as an inactive proenzyme in the bloodstream, and becomes activated during blood clotting. The active form, TAFIa, inhibits fibrinolysis by cleaving off C-terminal lysine residues from partially degraded fibrin that stimulates the tissue-type plasminogen activator-mediated conversion of plasminogen to plasmin. Consequently, removal of these lysines leads to less plasmin formation and subsequently to protection of the fibrin clot from break down. Moreover, TAFI may also play a role in other processes such as, inflammation and tissue repair. In this review, recent developments in TAFI research are discussed. PMID:15379716

  2. Data supporting the structural and functional characterization of Thrombin‐Activatable Fibrinolysis Inhibitor in breast cancer

    PubMed Central

    Fawzy, Manal S.; Toraih, Eman A.

    2015-01-01

    The data in this paper is related to the research article entitled “Thrombin-activatable fibrinolysis inhibitor Thr325Ile polymorphism and plasma level in breast cancer: A pilot study” (Fawzy et al., 2015) [1]. Many emerging studies have begun to unravel the pathophysiologic role of the fibrinolytic system in breast cancer (BC) progression (Zorio et al., 2008) [2]. Activation of the fibrinolytic plasminogen/plasmin system results in degradation of protein barriers, thereby mediating cell migration essential for tumor growth, angiogenesis, and dissemination (Castellino and Ploplis, 2005) [3]. In the current study, in silico data analysis of Thrombin-Activatable Fibrinolysis Inhibitor (TAFI) gene and protein has been done. Data have been retrieved from several databases mentioned in details in the text. Determination and analysis of the structural and functional impact of TAFI and its expression could help elucidate the contribution of the TAFI pathway to acquired hemostatic dysfunction and will form the basis of potential therapeutic strategies to manipulate this pathway. An inhibition of TAFI (e.g. by FXI inhibitors) will offer the therapeutic possibilities to improve the decreased fibrinolysis and increase the efficiency of fibrinolytic therapy in thrombotic disorders including cancer. PMID:26740968

  3. Activity of thrombin-activatable fibrinolysis inhibitor in the plasma of patients with abdominal aortic aneurysm.

    PubMed

    Dubis, Joanna; Zuk, Natalia; Grendziak, Ryszard; Zapotoczny, Norbert; Pfanhauser, Monika; Witkiewicz, Wojciech

    2014-04-01

    Patients with abdominal aortic aneurysm (AAA) experience impaired balance between fibrinolysis and coagulation, manifested by increased prothrombotic tendency and intensified inflammatory processes. The aim of this study was to evaluate the TAFI activity level (thrombin activatable fibrinolysis inhibitor) in the plasma of AAA patients. Plasma levels of PAI-1 (plasminogen activator inhibitor type 1), urokinase-type plasminogen activator and uPAR (urokinase-type plasminogen activator receptor) were measured as markers of fibrinolytic activity. The study showed that the activity of the thrombin-activatable fibrinolysis inhibitor in the plasma of AAA patients was significantly lower than in the plasma of the control individuals (64.6 ± 10.1 vs. 54.2 ± 10.9%, P < 0.0001). TAFI activity positively correlated with the white blood cell count (r = 0.486, P < 0.005). The uPAR concentration in the AAA patients was statistically significantly higher than in the control group and positively correlated with TAFI activity (r = 0.409, P = 0.02). The levels of PAI-1 and D-dimers (fibrin fragments) were significantly higher in patients with AAA than in the control group (44.3 ± 17.5 vs. 21.7 ± 8.7 ng/ml and 1869.6 ± 1490.1 vs. 181.5 ± 188.6 ng/ml, respectively). Lowered activity of the fibrinolysis inhibitor TAFI may heighten the blood fibrinolytic potential in AAA patients and contribute to the development of comorbidities. Therefore, TAFI participation in AAA pathogenesis cannot be excluded. PMID:24378973

  4. Thrombin-activatable fibrinolysis inhibitor activity and global fibrinolytic capacity in Type 1 diabetes: evidence for normal fibrinolytic state.

    PubMed

    Harmanci, Ayla; Kandemir, Nurgun; Dagdelen, Selcuk; Gonc, Nazli; Buyukasik, Yahya; Alikasifoglu, Ayfer; Kirazli, Serafettin; Ozon, Alev; Gurlek, Alper

    2006-01-01

    Hypofibrinolysis is a state that is commonly observed in type 2 diabetic patients, a finding also possibly related to obesity and insulin resistance. There is little information, however, regarding the status of fibrinolytic system in Type 1 diabetes, in particular as reflected by thrombin-activatable fibrinolysis inhibitor (TAFI) activity and global fibrinolytic capacity (GFC). To provide information in this respect, 30 Type 1 diabetic patients (median age=16) and 28 healthy controls (median age=14) were enrolled in this study. The median duration of diabetes was 7 years, and median HbA(1c) was 8.85% (range: 5.5-11.9%) in the diabetic group. None of the patients had macrovascular complications. Microvascular complications were present in a total of eight patients (nephropathy: n=5; retinopathy: n=3). A comparison of the TAFI activity between the patient (median 84.9, range: 71.5-103.3%) and the control groups (median=83.3, range: 63.7-97.4%) yielded no statistically significant difference (P=.950). Similarly, GFC was comparable between the two groups (median=8.22, range: 0.72-22.38 microg/ml, and median=13.32, range: 3.0-23.22 microg/ml, respectively, in the diabetic and control groups, P=.086). TAFI activity did not significantly correlate with age, albumin excretion, fasting plasma glucose, HbA(1c), D-dimer, and fibrinogen by Spearman rank correlation test. There was as a significant inverse correlation between GFC and TAFI activity (r=-.414, P=.006). Contrary to the previous observations in Type 2 diabetes, our data suggest that fibrinolytic activity is not adversely affected by Type 1 diabetes, and it has no relationship with the degree of metabolic control. PMID:16389166

  5. Association between thrombin-activatable fibrinolysis inhibitor gene polymorphisms and venous thrombosis risk: a meta-analysis.

    PubMed

    Wang, Wei; Ma, He; Lu, Lili; Sun, Guixiang; Liu, Dang; Zhou, Yunti; Tong, Yue; Lu, Zhaojun

    2016-06-01

    Thrombin-activatable fibrinolysis inhibitor (TAFI) is an important antifibrinolytic factor that has been shown in increased concentrations to be associated with an increased risk for venous thrombosis. However, the effect of TAFI gene polymorphisms on the risk of venous thrombosis remains debatable. The aim of the current study was to evaluate the association of three single nucleotide polymorphisms: 505G>A (rs3742264), 1040 C>T (rs1926447) and -438G>A (rs2146881) with venous thrombosis risk using a meta-analysis. A systematic literature search for eligible studies published before 20 January 2015 was conducted in PubMed, EMBASE, Web of Science, WanFang database and Chinese National Knowledge Infrastructure. We assessed the possible association by pooled odds ratio and its 95% confidence interval. A total of 14 independent case-control studies including 2970 cases and 3049 controls were enrolled in the final meta-analysis. A significant reduction of venous thrombosis risk in the 505G>A polymorphism was observed under allele comparison, homozygote comparison and recessive models, but opposite results were seen in Asians. Likewise, there was a significant decreased susceptibility to venous thrombosis in the 1040C>T polymorphism in homozygote comparison and recessive models. In the subgroup analysis, the nonvenous thromboembolism disease group showed a significantly increased venous thrombosis risk. Pooled estimates did not show evidence of association between -438G>A and venous thrombosis risk in any genetic model. This meta-analysis suggested that although the -438G>T polymorphism is not correlated with venous thrombosis risk in all models, a trend toward reduced risk still could be observed. The A allele and AA genotype of 505G>A in whites and the TT genotype of 1040C>T were significantly associated with a decreased risk of venous thrombosis, except in the non-venous thromboembolism group. PMID:26656901

  6. Isolation, Co-Crystallization and Structure-Based Characterization of Anabaenopeptins as Highly Potent Inhibitors of Activated Thrombin Activatable Fibrinolysis Inhibitor (TAFIa)

    PubMed Central

    Schreuder, Herman; Liesum, Alexander; Lönze, Petra; Stump, Heike; Hoffmann, Holger; Schiell, Matthias; Kurz, Michael; Toti, Luigi; Bauer, Armin; Kallus, Christopher; Klemke-Jahn, Christine; Czech, Jörg; Kramer, Dan; Enke, Heike; Niedermeyer, Timo H. J.; Morrison, Vincent; Kumar, Vasant; Brönstrup, Mark

    2016-01-01

    Mature thrombin activatable fibrinolysis inhibitor (TAFIa) is a carboxypeptidase that stabilizes fibrin clots by removing C-terminal arginines and lysines from partially degraded fibrin. Inhibition of TAFIa stimulates the degradation of fibrin clots and may help to prevent thrombosis. Applying a lead finding approach based on literature-mining, we discovered that anabaenopeptins, cyclic peptides produced by cyanobacteria, were potent inhibitors of TAFIa with IC50 values as low as 1.5 nM. We describe the isolation and structure elucidation of 20 anabaenopeptins, including 13 novel congeners, as well as their pronounced structure-activity relationships (SAR) with respect to inhibition of TAFIa. Crystal structures of the anabaenopeptins B, C and F bound to the surrogate protease carboxypeptidase B revealed the binding modes of these large (~850 Da) compounds in detail and explained the observed SAR, i.e. the strong dependence of the potency on a basic (Arg, Lys) exocyclic residue that addressed the S1’ binding pocket, and a broad tolerance towards substitutions in the pentacyclic ring that acted as a plug of the active site. PMID:27604544

  7. Isolation, Co-Crystallization and Structure-Based Characterization of Anabaenopeptins as Highly Potent Inhibitors of Activated Thrombin Activatable Fibrinolysis Inhibitor (TAFIa).

    PubMed

    Schreuder, Herman; Liesum, Alexander; Lönze, Petra; Stump, Heike; Hoffmann, Holger; Schiell, Matthias; Kurz, Michael; Toti, Luigi; Bauer, Armin; Kallus, Christopher; Klemke-Jahn, Christine; Czech, Jörg; Kramer, Dan; Enke, Heike; Niedermeyer, Timo H J; Morrison, Vincent; Kumar, Vasant; Brönstrup, Mark

    2016-01-01

    Mature thrombin activatable fibrinolysis inhibitor (TAFIa) is a carboxypeptidase that stabilizes fibrin clots by removing C-terminal arginines and lysines from partially degraded fibrin. Inhibition of TAFIa stimulates the degradation of fibrin clots and may help to prevent thrombosis. Applying a lead finding approach based on literature-mining, we discovered that anabaenopeptins, cyclic peptides produced by cyanobacteria, were potent inhibitors of TAFIa with IC50 values as low as 1.5 nM. We describe the isolation and structure elucidation of 20 anabaenopeptins, including 13 novel congeners, as well as their pronounced structure-activity relationships (SAR) with respect to inhibition of TAFIa. Crystal structures of the anabaenopeptins B, C and F bound to the surrogate protease carboxypeptidase B revealed the binding modes of these large (~850 Da) compounds in detail and explained the observed SAR, i.e. the strong dependence of the potency on a basic (Arg, Lys) exocyclic residue that addressed the S1' binding pocket, and a broad tolerance towards substitutions in the pentacyclic ring that acted as a plug of the active site. PMID:27604544

  8. Platelets Contain Tissue Factor Pathway Inhibitor-2 Derived from Megakaryocytes and Inhibits Fibrinolysis*

    PubMed Central

    Vadivel, Kanagasabai; Ponnuraj, Sathya-Moorthy; Kumar, Yogesh; Zaiss, Anne K.; Bunce, Matthew W.; Camire, Rodney M.; Wu, Ling; Evseenko, Denis; Herschman, Harvey R.; Bajaj, Madhu S.; Bajaj, S. Paul

    2014-01-01

    Tissue factor pathway inhibitor-2 (TFPI-2) is a homologue of TFPI-1 and contains three Kunitz-type domains and a basic C terminus region. The N-terminal domain of TFPI-2 is the only inhibitory domain, and it inhibits plasma kallikrein, factor XIa, and plasmin. However, plasma TFPI-2 levels are negligible (≤20 pm) in the context of influencing clotting or fibrinolysis. Here, we report that platelets contain significant amounts of TFPI-2 derived from megakaryocytes. We employed RT-PCR, Western blotting, immunohistochemistry, and confocal microscopy to determine that platelets, MEG-01 megakaryoblastic cells, and bone marrow megakaryocytes contain TFPI-2. ELISA data reveal that TFPI-2 binds factor V (FV) and partially B-domain-deleted FV (FV-1033) with Kd ∼9 nm and binds FVa with Kd ∼100 nm. Steady state analysis of surface plasmon resonance data reveal that TFPI-2 and TFPI-1 bind FV-1033 with Kd ∼36–48 nm and bind FVa with Kd ∼252–456 nm. Further, TFPI-1 (but not TFPI-1161) competes with TFPI-2 in binding to FV. These data indicate that the C-terminal basic region of TFPI-2 is similar to that of TFPI-1 and plays a role in binding to the FV B-domain acidic region. Using pull-down assays and Western blots, we show that TFPI-2 is associated with platelet FV/FVa. TFPI-2 (∼7 nm) in plasma of women at the onset of labor is also, in part, associated with FV. Importantly, TFPI-2 in platelets and in plasma of pregnant women inhibits FXIa and tissue-type plasminogen activator-induced clot fibrinolysis. In conclusion, TFPI-2 in platelets from normal or pregnant subjects and in plasma from pregnant women binds FV/Va and regulates intrinsic coagulation and fibrinolysis. PMID:25262870

  9. Enhanced endogenous thrombolysis induced by a specific factor Xa inhibitor, DX-9065a, evaluated in a rat arterial thrombolysis model in vivo.

    PubMed

    Hashimoto, Masaru; Onobayashi, Yuko; Oiwa, Kazuhiro; Giddings, John C; Yamamoto, Junichiro

    2002-04-15

    We have previously established an animal model to investigate mechanisms of arterial thrombolysis in vivo and have demonstrated that endogenous thrombolysis, mediated by thrombin-activatable fibrinolysis inhibitor, is enhanced by administration of specific thrombin inhibitors. The aim of the present study was to evaluate the effects of a synthetic and specific factor Xa inhibitor, DX-9065a, on endogenous fibrinolysis. Mural thrombi were formed in rat mesenteric arterioles by helium-neon laser irradiation in the presence of Evans blue. Thrombolysis was continuously monitored by video microscopy and was quantified using image analysis software. Oral and intravenous administration of DX-9065a enhanced endogenous thrombolysis in vivo. The mechanisms require additional investigation using other experimental systems, but nevertheless, the present results extended our previous findings and further suggested that the enhanced fibrinolysis might be due to depressed activity thrombin-activatable fibrinolysis inhibitor. The synthetic factor Xa inhibitor could provide the basis for a useful thrombolytic agent. PMID:12182917

  10. Role of adipose tissue in haemostasis, coagulation and fibrinolysis.

    PubMed

    Faber, D R; de Groot, Ph G; Visseren, F L J

    2009-09-01

    Obesity is associated with an increased incidence of insulin resistance (IR), type 2 diabetes mellitus and cardiovascular diseases. The increased risk for cardiovascular diseases could partly be caused by a prothrombotic state that exists because of abdominal obesity. Adipose tissue induces thrombocyte activation by the production of adipose tissue-derived hormones, often called adipokines, of which some such as leptin and adiponectin have been shown to directly interfere with platelet function. Increased adipose tissue mass induces IR and systemic low-grade inflammation, also affecting platelet function. It has been demonstrated that adipose tissue directly impairs fibrinolysis by the production of plasminogen activator inhibitor-1 and possibly thrombin-activatable fibrinolysis inhibitor. Adipose tissue may contribute to enhanced coagulation by direct tissue factor production, but hypercoagulability is likely to be primarily caused by affecting hepatic synthesis of the coagulation factors fibrinogen, factor VII, factor VIII and tissue factor, by releasing free fatty acids and pro-inflammatory cytokines (tumour necrosis factor-alpha, interleukin-1beta and interleukin-6) into the portal circulation and by inducing hepatic IR. Adipose tissue dysfunction could thus play a causal role in the prothrombotic state observed in obesity, by directly and indirectly affecting haemostasis, coagulation and fibrinolysis. PMID:19460118

  11. Bidirectional functions of thrombin on fibrinolysis: Evidence of thrombin-dependent enhancement of fibrinolysis provided by spontaneous plasma clot lysis.

    PubMed

    Tomczyk, Martyna; Suzuki, Yuko; Sano, Hideto; Brzoska, Tomasz; Tanaka, Hiroki; Urano, Tetsumei

    2016-07-01

    Besides procoagulant activity, thrombin exhibits anticoagulant and profibrinolytic activities. We demonstrated that the euglobulin clot lysis time (ECLT) was shortened by endogenously generated thrombin as a result of the inactivation of plasminogen activator inhibitor type 1 (PAI-1). In contrast, thrombin suppressed fibrinolytic activity through the activation of thrombin activatable fibrinolysis inhibitor (TAFI). Here, using three different clot lysis assays of the ECLT, the tissue plasminogen activator supplemented plasma clot lysis time (tPA-PCLT) and the spontaneous plasma clot lysis time (s-PCLT), we analyzed how the coagulation process modifies fibrinolysis. The ECLT was shortened by exogenously supplemented thrombin in a dose-dependent manner in the absence of calcium ion (Ca(++)), whereas this shortening was not observed in the presence of Ca(++) where endogenous prothrombin was effectively activated to thrombin. This shortening was also not observed for the tPA-PCLT, in which tPA is supplemented in excess and PAI-1 activity is mostly lost. On the contrary, thrombin dose-dependently prolonged the tPA-PCLT, which was mostly abolished by inhibitors of carboxypeptidase and activated FXIII, suggesting that the prolongation is TAFI- and Factor XIII-dependent. The s-PCLT was shortened when thrombin generation was boosted by supplementing tissue factor and phosphatidylserine together with Ca(++), which was more apparent in the presence of inhibitors of activated FXIII and activated TAFI. Thus, thrombin appeared to express its enhancing effect on fibrinolysis even in plasma, in addition to its inhibiting effect. These bidirectional functions of thrombin on fibrinolysis seem to take place on demand under different environments to maintain adequate vascular blood flow. PMID:27179129

  12. Engineering Kunitz Domain 1 (KD1) of Human Tissue Factor Pathway Inhibitor-2 to Selectively Inhibit Fibrinolysis

    PubMed Central

    Bajaj, Madhu S.; Ogueli, Godwin I.; Kumar, Yogesh; Vadivel, Kanagasabai; Lawson, Gregory; Shanker, Sreejesh; Schmidt, Amy E.; Bajaj, S. Paul

    2011-01-01

    Tissue factor pathway inhibitor-2 (TFPI-2) inhibits factor XIa, plasma kallikrein, and factor VIIa/tissue factor; accordingly, it has been proposed for use as an anticoagulant. Full-length TFPI-2 or its isolated first Kunitz domain (KD1) also inhibits plasmin; therefore, it has been proposed for use as an antifibrinolytic agent. However, the anticoagulant properties of TFPI-2 or KD1 would diminish its antifibrinolytic function. In this study, structure-based investigations and analysis of the serine protease profiles revealed that coagulation enzymes prefer a hydrophobic residue at the P2′ position in their substrates/inhibitors, whereas plasmin prefers a positively charged arginine residue at the corresponding position in its substrates/inhibitors. Based upon this observation, we changed the P2′ residue Leu-17 in KD1 to Arg (KD1-L17R) and compared its inhibitory properties with wild-type KD1 (KD1-WT). Both WT and KD1-L17R were expressed in Escherichia coli, folded, and purified to homogeneity. N-terminal sequences and mass spectra confirmed proper expression of KD1-WT and KD1-L17R. Compared with KD1-WT, the KD1-L17R did not inhibit factor XIa, plasma kallikrein, or factor VIIa/tissue factor. Furthermore, KD1-L17R inhibited plasmin with ∼6-fold increased affinity and effectively prevented plasma clot fibrinolysis induced by tissue plasminogen activator. Similarly, in a mouse liver laceration bleeding model, KD1-L17R was ∼8-fold more effective than KD1-WT in preventing blood loss. Importantly, in this bleeding model, KD1-L17R was equally or more effective than aprotinin or tranexamic acid, which have been used as antifibrinolytic agents to prevent blood loss during major surgery/trauma. Furthermore, as compared with aprotinin, renal toxicity was not observed with KD1-L17R. PMID:21115497

  13. Effect of heparin on TAFI-dependent inhibition of fibrinolysis: relative importance of TAFIa generated by clot-bound and fluid phase thrombin.

    PubMed

    Colucci, Mario; Pentimone, Anna; Binetti, Bianca M; Cramarossa, Marialisa; Piro, Donatella; Semeraro, Nicola

    2002-08-01

    Heparin has been proposed to enhance thrombolysis by inhibiting thrombin-dependent generation of activated TAFI (thrombin activatable fibrinolysis inhibitor), a carboxypeptidase that inhibits fibrinolysis. We evaluated the effect of heparin in an in vitro thrombolysis model consisting of a radiolabelled blood clot submerged in defibrinated plasma. Fibrinolysis was induced by adding t-PA (250 ng/ml) and calcium to the plasma bath. Control experiments indicated that thrombin generation induced by recalcification caused significant TAFI activation and inhibited clot lysis. Heparin (up to 1 U/ml), added to the plasma bath, failed to enhance clot lysis. Thrombin generation in the fluid phase was totally inhibited by heparin at concentrations > 0.5 U/ml. In contrast, thrombin generation on the clot surface was not inhibited by heparin (1 U/ml). TAFIa generation did occur in heparin-containing samples (1 U/ml) and amounted to about 10% of TAFIa formed in control samples. This low amount of TAFIa did exert antifibrinolytic activity as indicated by the observation that the addition of a specific TAFIa inhibitor (PTI) along with heparin enhanced clot lysis. Hirudin (10 micrograms/ml), at variance with heparin, inhibited clot-bound thrombin and enhanced clot lysis. These data show that heparin is unable to stimulate fibrinolysis through a TAFI-dependent mechanism, most likely because of its inefficiency in inhibiting thrombin generation on the clot surface. Moreover, they suggest that clot-bound thrombin plays a major role in TAFI-mediated inhibition of fibrinolysis through "localized" TAFIa generation. PMID:12195701

  14. Fibrinolysis and the control of blood coagulation

    PubMed Central

    Chapin, John C.; Hajjar, Katherine A.

    2014-01-01

    Fibrin plays an essential role in hemostasis as both the primary product of the coagulation cascade and the ultimate substrate for fibrinolysis. Fibrinolysis efficiency is greatly influenced by clot structure, fibrinogen isoforms and polymorphisms, the rate of thrombin generation, the reactivity of thrombus-associated cells such as platelets, and the overall biochemical environment. Regulation of the fibrinolytic system, like that of the coagulation cascade, is accomplished by a wide array of cofactors, receptors, and inhibitors. Fibrinolytic activity can be generated either on the surface of a fibrin-containing thrombus, or on cells that express profibrinolytic receptors. In a widening spectrum of clinical disorders, acquired and congenital defects in fibrinolysis contribute to disease morbidity, and new assays of global fibrinolysis now have potential predictive value in multiple clinical settings. Here, we summarize the basic elements of the fibrinolytic system, points of interaction with the coagulation pathway, and some recent clinical advances. PMID:25294122

  15. Effects of aliskiren, a renin inhibitor, on biomarkers of platelet activity, coagulation and fibrinolysis in subjects with multiple risk factors for vascular disease.

    PubMed

    Serebruany, V L; Malinin, A; Barsness, G; Vahabi, J; Atar, D

    2008-05-01

    Aliskiren, an octanamide, is nonpeptide, low molecular weight, orally active renin inhibitor effectively preventing angiotensin and aldosterone release. This drug has been recently approved for the treatment of hypertension. Considering potential links between hypertension, platelets, the coagulation cascade and fibrinolysis we sought to evaluate the effect of aliskiren on human biomarkers of hemostasis. In vitro effects of whole blood preincubation with escalating concentrations of aliskiren (500, 1,000 and 2,000 ng ml(-1)) were assessed in 20 aspirin-naive volunteers with multiple risk factors for vascular disease. A total of 33 biomarkers were measured, of which 18 are related to platelet function, 12 to coagulation and 3 to fibrinolysis. Pretreatment of blood samples with aliskiren 500 ng ml(-1) resulted in a significant increase of antithrombin-III (AT-III) activity (P=0.003). All other tested biomarkers were not significantly affected. Spiking whole blood with the higher aliskiren doses was associated with various trends in biomarker activity, where 1000 ng ml(-1) concentration mostly decreased (7/33), and 2,000 ng ml(-1) mostly increased (6/33) some biomarkers. In the therapeutic concentration of 500 ng ml(-1) aliskiren does not affect hemostatic biomarkers, except for a moderate but highly significant (P=0.003) increase of AT-III activity. Higher aliskiren doses were associated with more profound biomarker changes, but they are likely not to be clinically relevant since they show diverging (that is, both mild antiplatelet and platelet-activating) trends, and considering the 2- to 4-fold safety margin. It is suggested that antithrombotic properties of aliskiren be explored further in an ex vivo clinical setting. PMID:18273042

  16. The Crystal Structure of Thrombin-activable Fibrinolysis Inhibitor (TAFI) Provides the Structural Basis for Its Intrinsic Activity and the Short Half-life of TAFIa*♦

    PubMed Central

    Anand, Kanchan; Pallares, Irantzu; Valnickova, Zuzana; Christensen, Trine; Vendrell, Josep; Wendt, K. Ulrich; Schreuder, Herman A.; Enghild, Jan J.; Avilés, Francesc X.

    2008-01-01

    Mature thrombin-activable fibrinolysis inhibitor (TAFIa) is a highly unstable metallocarboxypeptidase that stabilizes blood clots by clipping C-terminal lysine residues from partially degraded fibrin. In accordance with its in vitro antifibrinolytic activity, animal studies have reported that inhibition of mature TAFI aids in the prevention of thrombosis. The level of TAFI activity is stringently regulated through (i) controlled proteolytic truncation of the zymogen (TAFI), generating the mature enzyme, TAFIa, and (ii) the short half-life of TAFIa. TAFI itself exhibits an intrinsic enzymatic activity, which is likely required to provide a baseline level of antifibrinolytic activity. The novel crystal structure presented here reveals that the active site of TAFI is accessible, providing the structural explanation for the its intrinsic activity. It also supports the notion that an “instability region” exists, in agreement with site-directed mutagenesis studies. Sulfate ions, bound to this region, point toward a potential heparin-binding site and could explain how heparin stabilizes TAFIa. PMID:18669641

  17. Variable Resistance to Plasminogen Activator Initiated Fibrinolysis for Intermediate-Risk Pulmonary Embolism

    PubMed Central

    Stubblefield, William B.; Alves, Nathan J.; Rondina, Matthew T.; Kline, Jeffrey A.

    2016-01-01

    Background We examine the clinical significance and biomarkers of tissue plasminogen activator (tPA)-catalyzed clot lysis time (CLT) in patients with intermediate-risk pulmonary embolism (PE). Methods Platelet-poor, citrated plasma was obtained from patients with PE. Healthy age- and sex-matched patients served as disease-negative controls. Fibrinogen, α2-antiplasmin, plasminogen, thrombin activatable fibrinolysis inhibitor (TAFI), plasminogen activator Inhibitor 1 (PAI-1), thrombin time and D-dimer were quantified. Clotting was induced using CaCl2, tissue factor, and phospholipid. Lysis was induced using 60 ng/mL tPA. Time to 50% clot lysis (CLT) was assessed by both thromboelastography (TEG) and turbidimetry (A405). Results Compared with disease-negative controls, patients with PE exhibited significantly longer mean CLT on TEG (+2,580 seconds, 95% CI 1,380 to 3,720 sec). Patients with PE and a short CLT who were treated with tenecteplase had increased risk of bleeding, whereas those with long CLT had significantly worse exercise tolerance and psychometric testing for quality of life at 3 months. A multivariate stepwise removal regression model selected PAI-1 and TAFI as predictive biomarkers of CLT. Conclusion The CLT from TEG predicted increased risk of bleeding and clinical failure with tenecteplase treatment for intermediate-risk PE. Plasmatic PAI-1 and TAFI were independent predictors of CLT. PMID:26866684

  18. Activatable Molecular Probes for Cancer Imaging

    PubMed Central

    Lee, Seulki; Xie, Jin; Chen, Xiaoyuan

    2013-01-01

    The development of highly sensitive and specific molecular probes for cancer imaging still remains a daunting challenge. Recently, interdisciplinary research at the interface of imaging sciences and bionanoconjugation chemistry has generated novel activatable imaging probes that can provide high-resolution imaging with ultra-low background signals. Activatable imaging probes are designed to amplify output imaging signals in response to specific biomolecular recognition or environmental changes in real time. This review introduces and highlights the unique design strategies and applications of various activatable imaging probes in cancer imaging. PMID:20388112

  19. Usefulness of human coagulation and fibrinolysis assays in domestic pigs.

    PubMed

    Münster, Anna-Marie Bloch; Olsen, Aage Kristian; Bladbjerg, Else-Marie

    2002-02-01

    Pigs are often used as animal models in research on blood coagulation and fibrinolysis. The usefulness of the assays applied within this field, and the knowledge of reference intervals are therefore essential and of utmost importance. In the study reported here, we investigated the applicability of commercial human coagulation and fibrinolysis assays for use with porcine plasma. In total, 22 functional and immunologic assays were applied to plasma obtained from domestic pigs, and the following blood coagulation and fibrinolysis variables were measured: prothrombin time, activated partial thromboplastin time, tissue factor, tissue factor pathway inhibitor, factor VII, protein C, protein S, prothrombin fragment 1+2, antithrombin, thrombin-antithrombin complexes, fibrinogen, soluble fibrin, urokinase-type plasminogen activator, plasmin inhibitor, plasminogen activator inhibitor 1, and D-dimer. We found that 11 of 12 functional assays, but only 3 of 10 immunoassays, were applicable to porcine plasma, and we determined the normal range of these variables. We conclude that human functional assays are useful in porcine plasma, whereas only a few immunologic assays can be used. However, precautions must be taken in interpretation of the results and in extrapolation toward human results because possible differences between porcine and human values can be due to species variations and/or methodologic errors. PMID:11900411

  20. [Fibrinolysis in acute myocardial infarct].

    PubMed

    Bleifeld, W

    1987-10-24

    Fibrinolysis has opened up a new avenue in the treatment of acute myocardial infarction (AMI). In principle, the rate of reperfusion depends on the type of compound used, the mode of administration and the time between onset of symptoms and the beginning of treatment. With intracoronary streptokinase the reperfusion rate is of the order of 85%. Intravenous urokinase administered as a bolus results in a reopening rate of 50-60%; a similar rate of reperfusion is achieved with rt-PA as infusion, while i.v. streptokinase produces about 50% reopened coronary vessels. The final infarct size is decreased in 70% of patients if fibrinolysis is initiated within 2.5 hours after the onset of symptoms and followed by reopening of the occluded vessel. This results in a lowering of in-hospital mortality, which in various studies is of the order of 45-60%.- Bearing in mind the contraindications, fibrinolysis should be initiated within 3 hours. Hemodynamic improvement by a decrease of infarct size may also be achieved beyond 3 hours in large anterior myocardial infarctions and in posterior infarctions with cardiogenic shock. Early initiation of thrombolysis is of major importance in improving left ventricular function and lowering mortality following acute myocardial infarction. Therefore, prehospital thrombolytic therapy should be considered. - In the postinfarction phase coronary angiography is indicated in patients with angina at rest, stable angina of ECG signs of ischemia. In this situation transfer to a specialized cardiology division for possible percutaneous transluminal angioplasty is indicated. - Reocclusion after successful thrombolysis occurs in 20-30%, and it is therefore important to avoid reinfarction to improve the long term prognosis after AMI.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3321420

  1. Impaired Fibrinolysis in the Antiphospholipid Syndrome

    PubMed Central

    Krone, Katie A.; Allen, Kristi L.; McCrae, Keith R.

    2010-01-01

    The antiphospholipid syndrome (APS) is characterized by venous and/or arterial thrombosis, or recurrent fetal loss, in the presence of antiphospholipid antibodies (APL). The pathogenesis of APS is multifaceted and involves numerous mechanisms including activation of endothelial cells, monocytes, and/or platelets; inhibition of natural anticoagulant pathways such as protein C, tissue factor inhibitor, and annexin A5; activation of the complement system; and impairment of the fibrinolytic system. Fibrinolysis—the process by which fibrin thrombi are remodeled and degraded—involves the conversion of plasminogen to plasmin by tissue plasminogen activator (tPA) or urokinase-type plasminogen activator, and is tightly regulated. Although the role of altered fibrinolysis in patients with APS is relatively understudied, several reports suggest that deficient fibrinolytic activity may contribute to the pathogenesis of disease in these patients. This article discusses the function of the fibrinolytic system and reviews studies that have reported alterations in fibrinolytic pathways that may contribute to thrombosis in patients with APL. Some of these mechanisms include elevations in plasminogen activator inhibitor-1 levels, inhibitory antibodies against tPA or other components of the fibrinolytic system, antibodies against annexin A2, and finally, antibodies to β2-glycoprotein-I (β2GPI) that block the ability of β2GPI to stimulate tPA-mediated plasminogen activation. PMID:20425534

  2. Assessment of Coagulation and Fibrinolysis in Pre-eclampsia

    PubMed Central

    Wood, S. M.; Burnett, D.; Picken, A. M.; Farrell, G. W.; Wolf, P.

    1974-01-01

    A method is described for distinguishing coagulation from fibrinolysis by three estimates of fibrinogen. This “fibrinogen series” together with plasma antithrombin and urinary urokinase have been compared in pregnant patients with venous thrombosis and pre-eclampsia. Evidence is presented for active coagulation during deterioration of the pre-eclampsia state and for enhanced fibrinolysis during improvement. PMID:4596483

  3. Enhancement of fibrinolysis in vitro by ultrasound.

    PubMed Central

    Francis, C W; Onundarson, P T; Carstensen, E L; Blinc, A; Meltzer, R S; Schwarz, K; Marder, V J

    1992-01-01

    The effect of ultrasound on the rate of fibrinolysis has been investigated using an in vitro system. Plasma or blood clots containing a trace label of 125I fibrin were suspended in plasma containing plasminogen activator and intermittently exposed to continuous wave 1-MHz ultrasound at intensities up to 8 W/cm2. Plasma clot lysis at 1 h with 1 microgram/ml recombinant tissue plasminogen activator (rt-PA) was 12.8 +/- 1.2% without ultrasound and was significantly (P = 0.0001) increased by exposure to ultrasound with greater lysis at 1 W/cm2 (18.0 +/- 1.4%), 2 W/cm2 (19.3 +/- 0.7%), 4 W/cm2 (22.8 +/- 1.8%), and 8 W/cm2 (58.7 +/- 7.1%). Significant increases in lysis were also seen with urokinase at ultrasound intensities of 2 W/cm2 and above. Exposure of clots to ultrasound in the absence of plasminogen activator did not increase lysis. Ultrasound exposure resulted in a marked reduction in the rt-PA concentration required to achieve an equivalent degree of lysis to that seen without ultrasound. For example, 15% lysis occurred in 1 h at 1 microgram/ml rt-PA without ultrasound or with 0.2 microgram/ml with ultrasound, a five-fold reduction in concentration. Ultrasound at 1 W/cm2 and above also potentiated lysis of retracted whole blood clots mediated by rt-PA or urokinase. The maximum temperature increase of plasma clots exposed to 4 W/cm2 ultrasound was only 1.7 degrees C, which could not explain the enhancement of fibrinolysis. Ultrasound exposure did not cause mechanical fragmentation of the clot into sedimentable fragments, nor did it alter the sizes of plasmic derivatives as demonstrated by SDS polyacrylamide gel electrophoresis. We conclude that ultrasound at 1 MHz potentiates enzymatic fibrinolysis by a nonthermal mechanism at energies that can potentially be applied and tolerated in vivo to accelerate therapeutic fibrinolysis. Images PMID:1430229

  4. Activatable Optical Probes for the Detection of Enzymes

    PubMed Central

    Drake, Christopher R.; Miller, David C.; Jones, Ella F.

    2013-01-01

    The early detection of many human diseases is crucial if they are to be treated successfully. Therefore, the development of imaging techniques that can facilitate early detection of disease is of high importance. Changes in the levels of enzyme expression are known to occur in many diseases, making their accurate detection at low concentrations an area of considerable active research. Activatable fluorescent probes show immense promise in this area. If properly designed they should exhibit no signal until they interact with their target enzyme, reducing the level of background fluorescence and potentially endowing them with greater sensitivity. The mechanisms of fluorescence changes in activatable probes vary. This review aims to survey the field of activatable probes, focusing on their mechanisms of action as well as illustrating some of the in vitro and in vivo settings in which they have been employed. PMID:23519774

  5. Protease-activated receptors mediate crosstalk between coagulation and fibrinolysis.

    PubMed

    McEachron, Troy A; Pawlinski, Rafal; Richards, Kristy L; Church, Frank C; Mackman, Nigel

    2010-12-01

    The coagulation and fibrinolytic systems contribute to malignancy by increasing angiogenesis, tumor growth, tumor invasion, and tumor metastasis. Oncogenic transformation increases the expression of tissue factor (TF) that results in local generation of coagulation proteases and activation of protease-activated receptor (PAR)-1 and PAR-2. We compared the PAR-dependent expression of urokinase plasminogen activator (uPA) and plasminogen activator inhibitor (PAI)-1 in 2 murine mammary adencocarcinoma cell lines: metastatic 4T1 cells and nonmetastatic 67NR cells. 4T1 cells expressed TF, PAR-1 and PAR-2 whereas 67NR cells expressed TF and PAR-1. We also silenced PAR-1 or PAR-2 expression in the 4T1 cells. We discovered 2 distinct mechanisms for PAR-dependent expression of uPA and PAI-1. First, we found that factor Xa or thrombin activation of PAR-1 led to a rapid release of stored intracellular uPA into the culture supernatant. Second, thrombin transactivation of a PAR-1/PAR-2 complex resulted in increases in PAI-1 mRNA and protein expression. Cells lacking PAR-2 failed to express PAI-1 in response to thrombin and factor Xa did not activate the PAR-1/PAR-2 complex. Our results reveal how PAR-1 and PAR-2 on tumor cells mediate crosstalk between coagulation and fibrinolysis. PMID:20736455

  6. Protease-activated receptors mediate crosstalk between coagulation and fibrinolysis

    PubMed Central

    McEachron, Troy A.; Pawlinski, Rafal; Richards, Kristy L.; Church, Frank C.

    2010-01-01

    The coagulation and fibrinolytic systems contribute to malignancy by increasing angiogenesis, tumor growth, tumor invasion, and tumor metastasis. Oncogenic transformation increases the expression of tissue factor (TF) that results in local generation of coagulation proteases and activation of protease-activated receptor (PAR)-1 and PAR-2. We compared the PAR-dependent expression of urokinase plasminogen activator (uPA) and plasminogen activator inhibitor (PAI)-1 in 2 murine mammary adencocarcinoma cell lines: metastatic 4T1 cells and nonmetastatic 67NR cells. 4T1 cells expressed TF, PAR-1 and PAR-2 whereas 67NR cells expressed TF and PAR-1. We also silenced PAR-1 or PAR-2 expression in the 4T1 cells. We discovered 2 distinct mechanisms for PAR-dependent expression of uPA and PAI-1. First, we found that factor Xa or thrombin activation of PAR-1 led to a rapid release of stored intracellular uPA into the culture supernatant. Second, thrombin transactivation of a PAR-1/PAR-2 complex resulted in increases in PAI-1 mRNA and protein expression. Cells lacking PAR-2 failed to express PAI-1 in response to thrombin and factor Xa did not activate the PAR-1/PAR-2 complex. Our results reveal how PAR-1 and PAR-2 on tumor cells mediate crosstalk between coagulation and fibrinolysis. PMID:20736455

  7. Blood coagulation and fibrinolysis in aortic valve stenosis: links with inflammation and calcification.

    PubMed

    Natorska, J; Undas, A

    2015-08-01

    Aortic valve stenosis (AS) increasingly afflicts our aging population. However, the pathobiology of the disease is still poorly understood and there is no effective pharmacotherapy for treating those at risk for clinical progression. The progression of AS involves complex inflammatory and fibroproliferative processes that resemble to some extent atherosclerosis. Accumulating evidence indicates that several coagulation proteins and its inhibitors, including tissue factor, tissue factor pathway inhibitor, prothrombin, factor XIII, von Willebrand factor, display increased expression within aortic stenotic valves, predominantly on macrophages and myofibroblasts around calcified areas. Systemic impaired fibrinolysis, along with increased plasma and valvular expression of plasminogen activator inhibitor-1, has also been observed in patients with AS in association with the severity of the disease. There is an extensive cross-talk between inflammation and coagulation in stenotic valve tissue which contributes to the calcification and mineralisation of the aortic valve leaflets. This review summarises the available data on blood coagulation and fibrinolysis in AS with the emphasis on their interactions with inflammation and calcification. PMID:25809537

  8. Postinjury Fibrinolysis Shutdown: Rationale for Selective Tranexamic Acid

    PubMed Central

    Moore, Ernest E.; Moore, Hunter B.; Gonzalez, Eduardo; Chapman, Michael P.; Hansen, Kirk C.; Sauaia, Angela; Silliman, Christopher C.; Banerjee, Anirban

    2015-01-01

    Postinjury systemic fibrinolysis has been recognized as a biologic process for more than 200 years, but the specific mechanisms of regulation and their clinical implications remain to be elucidated. By the 1950s, the plasminogen-plasmin-antiplasmin system was established as critical in preserving microvascular patency during blood clotting to maintain hemostasis. The challenges in modulating systemic fibrinolysis became evident soon thereafter. In the 1960s systemic fibrinolysis was identified by thrombelastography (TEG) during the anhepatic phase of liver transplantation, prompting the recommendation for intraoperative antifibrinolytics. But the administration of antifibrinolytic was associated with fatal postoperative pulmonary emboli. During the same period, there was experimental evidence that antifibrinolytics prevented irreversible hemorrhagic shock. More recently, a randomized trial indicated that plasmin inhibition during coronary artery bypass grafting was associated with increased mortality. The interest in antifibrinolytic therapy for trauma induced coagulopathy (TIC) is a relatively recent event, largely driven by the increasing use of viscoelastic hemostatic assays. The CRASH-2 trial, published in 2010, stimulated worldwide enthusiasm for tranexamic acid (TXA). However, the limitations of this study were soon acknowledged, raising concern for the unbridled use of TXA. Most recently, the documentation of fibrinolysis shutdown soon after injury has highlighted the potential adverse effects due to the untimely administration of TXA. A recent retrospective analysis in severely injured patients supports this hypothesis. But final clarity of this volatile topic awaits the completion of the current ongoing randomized clinical trials throughout the world. PMID:26002266

  9. A Simple Way to Visualize Fibrinolysis in the Classroom

    ERIC Educational Resources Information Center

    Nurachman, Zeily; Hermawan, Jatnika; Rachmayanti, Yanti; Baradja, Lubna

    2003-01-01

    Laboratory demonstration, as well as biochemistry lecture, has been used to complement explanation of biochemical processes. The laboratory demonstration is very useful in teaching biochemistry to students who lack background in biology. The experimental model of fibrinolysis described here presents a complex biological reaction in simplified…

  10. Photo-activatable Cre recombinase regulates gene expression in vivo.

    PubMed

    Schindler, Suzanne E; McCall, Jordan G; Yan, Ping; Hyrc, Krzystof L; Li, Mingjie; Tucker, Chandra L; Lee, Jin-Moo; Bruchas, Michael R; Diamond, Marc I

    2015-01-01

    Techniques allowing precise spatial and temporal control of gene expression in the brain are needed. Herein we describe optogenetic approaches using a photo-activatable Cre recombinase (PA-Cre) to stably modify gene expression in the mouse brain. Blue light illumination for 12 hours via optical fibers activated PA-Cre in the hippocampus, a deep brain structure. Two-photon illumination through a thinned skull window for 100 minutes activated PA-Cre within a sub-millimeter region of cortex. Light activation of PA-Cre may allow permanent gene modification with improved spatiotemporal precision compared to standard methods. PMID:26350769

  11. Novel Bioluminescent Activatable Reporter for Src Tyrosine Kinase Activity in Living Mice.

    PubMed

    Leng, Weibing; Li, Dezhi; Chen, Liang; Xia, Hongwei; Tang, Qiulin; Chen, Baoqin; Gong, Qiyong; Gao, Fabao; Bi, Feng

    2016-01-01

    Aberrant activation of the Src kinase is implicated in the development of a variety of human malignancies. However, it is almost impossible to monitor Src activity in an in vivo setting with current biochemical techniques. To facilitate the noninvasive investigation of the activity of Src kinase both in vitro and in vivo, we developed a genetically engineered, activatable bioluminescent reporter using split-luciferase complementation. The bioluminescence of this reporter can be used as a surrogate for Src activity in real time. This hybrid luciferase reporter was constructed by sandwiching a Src-dependent conformationally responsive unit (SH2 domain-Srcpep) between the split luciferase fragments. The complementation bioluminescence of this reporter was dependent on the Src activity status. In our study, Src kinase activity in cultured cells and tumor xenografts was monitored quantitatively and dynamically in response to clinical small-molecular kinase inhibitors, dasatinib and saracatinib. This system was also applied for high-throughput screening of Src inhibitors against a kinase inhibitor library in living cells. These results provide unique insights into drug development and pharmacokinetics/phoarmocodynamics of therapeutic drugs targeting Src signaling pathway enabling the optimization of drug administration schedules for maximum benefit. Using both Firefly and Renilla luciferase imaging, we have successfully monitored Src tyrosine kinase activity and Akt serine/threonine kinase activity concurrently in one tumor xenograft. This dual luciferase reporter imaging system will be helpful in exploring the complex signaling networks in vivo. The strategies reported here can also be extended to study and image other important kinases and the cross-talks among them. PMID:26941850

  12. Novel Bioluminescent Activatable Reporter for Src Tyrosine Kinase Activity in Living Mice

    PubMed Central

    Leng, Weibing; Li, Dezhi; Chen, Liang; Xia, Hongwei; Tang, Qiulin; Chen, Baoqin; Gong, Qiyong; Gao, Fabao; Bi, Feng

    2016-01-01

    Aberrant activation of the Src kinase is implicated in the development of a variety of human malignancies. However, it is almost impossible to monitor Src activity in an in vivo setting with current biochemical techniques. To facilitate the noninvasive investigation of the activity of Src kinase both in vitro and in vivo, we developed a genetically engineered, activatable bioluminescent reporter using split-luciferase complementation. The bioluminescence of this reporter can be used as a surrogate for Src activity in real time. This hybrid luciferase reporter was constructed by sandwiching a Src-dependent conformationally responsive unit (SH2 domain-Srcpep) between the split luciferase fragments. The complementation bioluminescence of this reporter was dependent on the Src activity status. In our study, Src kinase activity in cultured cells and tumor xenografts was monitored quantitatively and dynamically in response to clinical small-molecular kinase inhibitors, dasatinib and saracatinib. This system was also applied for high-throughput screening of Src inhibitors against a kinase inhibitor library in living cells. These results provide unique insights into drug development and pharmacokinetics/phoarmocodynamics of therapeutic drugs targeting Src signaling pathway enabling the optimization of drug administration schedules for maximum benefit. Using both Firefly and Renilla luciferase imaging, we have successfully monitored Src tyrosine kinase activity and Akt serine/threonine kinase activity concurrently in one tumor xenograft. This dual luciferase reporter imaging system will be helpful in exploring the complex signaling networks in vivo. The strategies reported here can also be extended to study and image other important kinases and the cross-talks among them. PMID:26941850

  13. Nanoparticle-mediated delivery of a rapidly activatable prodrug of SN-38 for neuroblastoma therapy

    PubMed Central

    Alferiev, Ivan S.; Iyer, Radhika; Croucher, Jamie L.; Adamo, Richard F.; Zhang, Kehan; Mangino, Jennifer L.; Kolla, Venkatadri; Fishbein, Ilia; Brodeur, Garrett M.; Levy, Robert J.; Chorny, Michael

    2015-01-01

    Nanomedicine-based strategies have the potential to improve therapeutic performance of a wide range of anticancer agents. However, the successful implementation of nanoparticulate delivery systems requires the development of adequately sized nanocarriers delivering their therapeutic cargo to the target in a protected, pharmacologically active form. The present studies focused on a novel nanocarrier-based formulation strategy for SN-38, a topoisomerase I inhibitor with proven anticancer potential, whose clinical application is compromised by toxicity, poor stability and incompatibility with conventional delivery vehicles. SN-38 encapsulated in biodegradable sub-100 nm sized nanoparticles (NP) in the form of its rapidly activatable prodrug derivative with tocopherol succinate potently inhibited the growth of neuroblastoma cells in a dose- and exposure time-dependent manner, exhibiting a delayed response pattern distinct from that of free SN-38. In a xenograft model of neuroblastoma, prodrug-loaded NP caused rapid regression of established large tumors, significantly delayed tumor regrowth after treatment cessation and markedly extended animal survival. The NP formulation strategy enabled by a reversible chemical modification of the drug molecule offers a viable means for SN-38 delivery achieving sustained intratumoral drug levels and contributing to the potency and extended duration of antitumor activity, both prerequisites for effective treatment of neuroblastoma and other cancers. PMID:25770994

  14. Coagulation and Fibrinolysis Indicators and Placental Malaria Infection in an Area Characterized by Unstable Malaria Transmission in Central Sudan

    PubMed Central

    Mostafa, Amged G.; Bilal, Naser E.; Abass, Awad-Elkareem; Elhassan, Elhassan M.; Mohmmed, Ahmed A.; Adam, Ishag

    2015-01-01

    This study aimed to investigate coagulation, fibrinolysis indicators, and malaria during pregnancy. Methods. A cross-sectional study was conducted at Medani, Sudan. Sociodemographic characteristics were gathered from each parturient woman (163) and malaria was investigated by blood film and placental histology. Protein C, protein S, antithrombin-III, tissue factor pathway inhibitor (TFPI), and plasminogen activator inhibitor-1 levels (PAI-1) were measured using ELISA. Results. One (0.6%), three (1.8), and 19 (11.7%) of the placentae showed active, chronic, and past infection on a histopathological examination, respectively, while 140 (85.9%) of them showed no signs of malaria infection. While the mean [SD] of the protein C, antithrombin-III, and TFPI was significantly lower, there was no significant difference in protein S and PAI-1 levels in women with placental malaria infection (n = 23) compared to those without placental malaria infection (140). In linear regression, placental malaria infection was associated with antithrombin-III. There was no association between placental malaria infections and protein C, protein S, TFPI, and PAI-1 levels. There was no association between hemoglobin, birth weight, and the investigated coagulation and fibrinolysis indicators. Conclusion. This study showed significantly lower levels of protein C, antithrombin-III, and TFPI in women with placental malaria infections. PMID:26295004

  15. Impacts of laparoscopic hysterectomy on functions of coagulation and fibrinolysis system.

    PubMed

    Zhao, Honghui; Xiao, Wei; Hu, Chunjie; Gao, Xiaoxu; Zhu, Yumei; Yang, Xiaofeng

    2016-06-01

    The main objective of the study is to compare the impacts of laparoscopic hysterectomy and total abdominal hysterectomy on the functions of coagulation and fibrinolysis system. Seventy-five patients who had undergone hysterectomy were randomly divided into laparoscopic hysterectomy group (n = 38) and total abdominal hysterectomy group (n = 37). The prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen, D-dimer, von Willebrand factor, α-granule membrane protein-140, thrombin-activated fibrinolysis inhibitor (TAFI) and platelet count were detected at preoperative 24 h (N0), postoperative 24 h (N1) and postoperative 48 h (N2). Compared with N0, values of PT, APTT and TT were significantly decreased at N1 in both groups, whereas von Willebrand factor, platelet count and α-granule membrane protein-140 levels at N1 were significantly increased (P < 0.05). There was no significant difference between N0 and N2 (P > 0.05). Compared with N0, fibrinogen, D-dimer and TAFI levels in both groups were significantly higher at N1 (P < 0.05), and there was no significant difference between N0 and N2 (P > 0.05). The intergroup comparison showed no significant difference of above indexes between two groups (P > 0.05). The univariate analysis showed that TAFI was negatively correlated with TT (r = -0.365, P < 0.01), APTT (r = -0.183, P < 0.05) and PT (r = -0.121, P < 0.05), whereas not correlated with other indicators. Laparoscopic hysterectomy may increase the risk of postoperative venous thrombosis. PMID:26761585

  16. Influence of solar activity on fibrinolysis and fibrinogenolysis. [statistical correlation between solar flare and blood coagulation indices

    NASA Technical Reports Server (NTRS)

    Marchenko, V. I.

    1974-01-01

    During periods of high solar activity fibrinolysis and fibrinogenolysis are increased. A direct correlative relationship is established between the indices of fibrinolysis, fibrinogenolysis and solar flares which were recorded two days before the blood was collected for analysis.

  17. Influence of synoptic processes on fibrinolysis and fibrinogenolysis in healthy persons. [meteorological effects on blood coagulation

    NASA Technical Reports Server (NTRS)

    Marchenko, V. I.

    1974-01-01

    It is shown that on days with frontal activity in the atmosphere the levels of fibrinolysis and fibrinogenolysis are increased. The reactions of fibrinolysis and fibrinogenolysis to the passage of warm and cold fronts varies with the season of the year.

  18. The influence of weather on fibrinolysis and fibrinogenolysis. [in human body

    NASA Technical Reports Server (NTRS)

    Marchenko, V. I.

    1974-01-01

    Analysis of fibrinolysis and fibrinogenolysis indices by month showed an increase in the activity of these processes from winter to summer (1967-1968). At all seasons of the year, fibrinolysis and fibrinogenolysis increase during weather of the cyclonic type with passage of fronts and sharp fluctuations in meteorological factors in the atmosphere.

  19. Markers of Thrombogenesis and Fibrinolysis and Their Relation to Inflammation and Endothelial Activation in Patients with Idiopathic Pulmonary Arterial Hypertension

    PubMed Central

    Kopeć, Grzegorz; Moertl, Deddo; Steiner, Sabine; Stępień, Ewa; Mikołajczyk, Tomasz; Podolec, Jakub; Waligóra, Marcin; Stępniewski, Jakub; Tomkiewicz-Pająk, Lidia; Guzik, Tomasz; Podolec, Piotr

    2013-01-01

    Background Chronic anticoagulation is a standard of care in idiopathic pulmonary arterial hypertension (IPAH). However, hemostatic abnormalities in this disease remain poorly understood. Therefore, we aimed to study markers of thrombogenesis and fibrinolysis in patients with IPAH. Methods We studied 27 consecutive patients (67% female) with IPAH aged 50.0 years (IQR: 41.0 - 65.0) and 16 controls without pulmonary hypertension. Prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin (TAT) complexes were measured to assess thrombogenesis; tissue-type plasminogen activator (tPA) antigen and plasmin-anti-plasmin complex to characterize activation of fibrinolysis; plasminogen activator inhibitor 1 (PAI-1) to measure inhibition of fibrinolysis; and endothelin-1 (ET-1) and interleukin-6 (IL-6) to assess endothelial activation and systemic inflammation, respectively. In addition, in treatment-naive IPAH patients these markers were assessed after 3 months of PAH-specific therapies. Results TPA (10.1[6.8-15.8] vs 5.2[3.3-7.3] ng/ml, p<0.001), plasmin-anti-plasmin (91.5[60.3-94.2] vs 55.8[51.1-64.9] ng/ml, p<0.001), IL-6 (4.9[2.5-7.9] vs 2.1[1.3-3.8] pg/ml, p=0.001) and ET-1 (3.7 [3.3-4.5] vs 3.4[3.1-3.5], p= 0.03) were higher in patients with IPAH than in controls. In IPAH patients plasmin-anti-plasmin and tPA correlated positively with IL-6 (r=0.39, p=0.04 and r=0.63, p<0.001, respectively) and ET-1 (r=0.55, p=0.003 and r=0.59, p=0.001, respectively). No correlation was found between tPA or plasmin-anti-plasmin and markers of thrombogenesis. Plasmin-anti-plasmin decreased after 3 months of PAH specific therapy while the other markers remained unchanged. Conclusions In the present study we showed that markers of fibrynolysis were elevated in patients with IPAH however we did not find a clear evidence for increased thrombogenesis in this group of patients. Fibrinolysis, inflammation, and endothelial activation were closely interrelated in IPAH. PMID:24312667

  20. Extracellularly activatable nanocarriers for drug delivery to tumors

    PubMed Central

    Yeo, Yoon

    2014-01-01

    Introduction Nanoparticles for drug delivery to tumors need to satisfy two seemingly conflicting requirements: they should maintain physical and chemical stability during circulation and be able to interact with target cells and release drug at desired locations with no substantial delay. Unique microenvironment of tumors and externally-applied stimuli provide a useful means to maintain a balance between the two requirements. Areas covered We discuss nanoparticulate drug carriers that maintain stable structures in normal conditions but respond to stimuli for spatiotemporal control of drug delivery. We first define the desired effects of extracellular activation of nanoparticles and frequently used stimuli and review examples of extracellularly activated nanoparticles. Expert opinion Several challenges remain in developing extracellularly activatable nanoparticles. First, some of the stimuli-responsive NPs undergo incremental changes in response to stimuli, losing circulation stability. Second, the applicability of stimuli in clinical settings is limited due to the occasional occurrence of the activating conditions in normal tissues. Third, the construction of stimuli-responsive nanoparticles involves increasing complexity in nanoparticle structure and production methods. Future efforts are needed to identify new targeting conditions and increase the contrast between activated and non-activated NPs, while keeping the production methods simple and scalable. PMID:24950343

  1. Inhibitors

    MedlinePlus

    ... Community Counts Blood Safety Inhibitors Articles & Key Findings Free Materials Videos Starting the Conversation Playing it Safe A Look at Hemophilia Joint Range of Motion My Story Links to Other Websites ...

  2. Changes in coagulation and fibrinolysis of post-SARS osteonecrosis in a Chinese population

    PubMed Central

    Sun, Wei; Shi, Zhen–cai; Zhang, Nian–fei; Zhang, Yuan–chun

    2006-01-01

    The purpose of this study was to detect changes in coagulation and fibrinolysis of post-severe acute respiratory syndrome (SARS) Chinese patients with osteonecrosis, investigate the aetiology of post-SARS osteonecrosis (ON), and select the sensitive molecular markers for identifying the susceptible population. For this study, blood samples were collected from 88 patients with post-SARS ON and 52 healthy people. Activated partial thromboplastin time (APTT), protein C (PC), antithrombin III (AT–III), plasminogen activator inhibitor (PAI), activated protein C resistance (APC–R), plasminogen (PLG), von Willebrand’s factor(vWF), D–dimer (D–D), fibrinogen (Fib), and homocysteine (HCY) were examined by enzyme-linked immunosorbent assay (ELISA). We noted that blood agents of patients with ON changed obviously. APTT, PC, AT–III, PAI, APC–R, and PLG were significantly different between the two groups. Hypercoagulation and hypofibrinolysis were found in patients with post-SARS ON. Therefore, these examinations can be used to screen a population susceptible to ON. Measurements of APTT, PC, AT–III, PAI, APC–R, and PLG are sensitive blood tests for screening purposes. PMID:16547717

  3. Inhibition by CāINH of Hageman Factor Fragment Activation of Coagulation, Fibrinolysis, and Kinin Generation

    PubMed Central

    Schreiber, Alan D.; Kaplan, Allen P.; Austen, K. Frank

    1973-01-01

    Highly purified inhibitor of the first component of complement (CāINH) was shown to inhibit the capacity of active Hageman factor fragments to initiate kinin generation, fibrinolysis, and coagulation. The inhibition of prealbumin Hageman factor fragments observed was dependent upon the time of interaction of the fragments with CāINH and not to an effect upon kallikrein or plasmin generated. The inhibition of the coagulant activity of the intermediate sized Hageman factor fragment by CāINH was not due to an effect on PTA or other clotting factors. The inhibition by CāINH of both the prealbumin and intermediate sized Hageman factor fragments occurred in a dose response fashion. The CāINH did not appear to be consumed when the activity of the Hageman factor fragments was blocked, although the fragments themselves could no longer be recovered functionally or as a protein on alkaline disc gel electrophoretic analysis. These results suggest that the CāINH may have an enzymatic effect on the fragments or that an additional site on CāINH is involved in Cā inactivation. Images PMID:4703226

  4. The role of coagulation/fibrinolysis during Streptococcus pyogenes infection

    PubMed Central

    Loof, Torsten G.; Deicke, Christin; Medina, Eva

    2014-01-01

    The hemostatic system comprises platelet aggregation, coagulation and fibrinolysis and is a host defense mechanism that protects the integrity of the vascular system after tissue injury. During bacterial infections, the coagulation system cooperates with the inflammatory system to eliminate the invading pathogens. However, pathogenic bacteria have frequently evolved mechanisms to exploit the hemostatic system components for their own benefit. Streptococcus pyogenes, also known as Group A Streptococcus, provides a remarkable example of the extraordinary capacity of pathogens to exploit the host hemostatic system to support microbial survival and dissemination. The coagulation cascade comprises the contact system (also known as the intrinsic pathway) and the tissue factor pathway (also known as the extrinsic pathway), both leading to fibrin formation. During the early phase of S. pyogenes infection, the activation of the contact system eventually leads to bacterial entrapment within a fibrin clot, where S. pyogenes is immobilized and killed. However, entrapped S. pyogenes can circumvent the antimicrobial effect of the clot by sequestering host plasminogen on the bacterial cell surface that, after conversion into its active proteolytic form, plasmin, degrades the fibrin network and facilitates the liberation of S. pyogenes from the clot. Furthermore, the surface-localized fibrinolytic activity also cleaves a variety of extracellular matrix proteins, thereby enabling S. pyogenes to migrate across barriers and disseminate within the host. This review summarizes the knowledge gained during the last two decades on the role of coagulation/fibrinolysis in host defense against S. pyogenes as well as the strategies developed by this pathogen to evade and exploit these host mechanisms for its own benefit. PMID:25309880

  5. Role of P38 MAPK on MMP Activity in Photothrombotic Stroke Mice as Measured using an Ultrafast MMP Activatable Probe

    PubMed Central

    Chang, Di; Wang, Yuan-Cheng; Bai, Ying-Ying; Lu, Chun-Qiang; Xu, Ting-Ting; Zhu, Lei; Ju, Shenghong

    2015-01-01

    Matrix metalloproteinases (MMPs) exert a dual effect in ischemic stroke and thus represent an ideal target for detection and therapy. However, to date, all clinical trials of MMP inhibitors have failed, and alternative drug candidates and therapeutic targets are urgently required. Nonetheless, further investigations are limited by the lack of non-invasive imaging techniques. Here, we report a novel, fast and ultrasensitive MMP activatable optical imaging probe for the dynamic visualization of MMP activity in photothrombotic stroke mice. This probe provides a significant signal enhancement in as little as 15 min, with the highest signal intensity occurring at 1 h post-injection, and shows high sensitivity in measuring MMP activity alterations, which makes it specifically suitable for the real-time visualization of MMP activity and drug discovery in preclinical research. Moreover, using this probe, we successfully demonstrate that the regulation of the p38 mitogen-activated protein kinase (MAPK) signal pathway is capable of modulating MMP activity after stroke, revealing a novel regulatory mechanism of postischemic brain damage and overcoming the limitations of traditional therapeutic strategies associated with MMP inhibitors by using a non-invasive molecular imaging method. PMID:26581247

  6. A two-photon activatable amino acid linker for the induction of fluorescence.

    PubMed

    Friedrich, Felix; Klehs, Kathrin; Fichte, Manuela A H; Junek, Stephan; Heilemann, Mike; Heckel, Alexander

    2015-10-28

    A new one- and two-photon activatable fluorophore based on ATTO565 was developed using a photolabile linker that simultaneously acts as a quencher. It is especially interesting for protein and peptide applications because it can be incorporated by standard peptide chemistry. The application of the new fluorogenic construct in super-resolution microscopy of antibody conjugates is shown. PMID:26343765

  7. An acid-cleavable phthalocyanine tetramer as an activatable photosensitiser for photodynamic therapy.

    PubMed

    Chow, Sun Y S; Lo, Pui-Chi; Ng, Dennis K P

    2016-08-16

    An acetal-linked self-quenched zinc(ii) phthalocyanine tetramer has been prepared. In an acidic environment in phosphate buffered saline or inside tumour cells, the phthalocyanine units of the tetramer are separated thereby restoring the fluorescence emission and singlet oxygen production. This response enables this compound to serve as a promising activatable photosensitiser for photodynamic therapy. PMID:27396392

  8. Physical Determinants of Fibrinolysis in Single Fibrin Fibers

    PubMed Central

    Bucay, Igal; O’Brien, E. Tim; Wulfe, Steven D.; Superfine, Richard; Wolberg, Alisa S.; Falvo, Michael R.; Hudson, Nathan E.

    2015-01-01

    Fibrin fibers form the structural backbone of blood clots; fibrinolysis is the process in which plasmin digests fibrin fibers, effectively regulating the size and duration of a clot. To understand blood clot dissolution, the influence of clot structure and fiber properties must be separated from the effects of enzyme kinetics and perfusion rates into clots. Using an inverted optical microscope and fluorescently-labeled fibers suspended between micropatterned ridges, we have directly measured the lysis of individual fibrin fibers. We found that during lysis 64 ± 6% of fibers were transected at one point, but 29 ± 3% of fibers increase in length rather than dissolving or being transected. Thrombin and plasmin dose-response experiments showed that the elongation behavior was independent of plasmin concentration, but was instead dependent on the concentration of thrombin used during fiber polymerization, which correlated inversely with fiber diameter. Thinner fibers were more likely to lyse, while fibers greater than 200 ± 30 nm in diameter were more likely to elongate. Because lysis rates were greatly reduced in elongated fibers, we hypothesize that plasmin activity depends on fiber strain. Using polymer physics- and continuum mechanics-based mathematical models, we show that fibers polymerize in a strained state and that thicker fibers lose their prestrain more rapidly than thinner fibers during lysis, which may explain why thick fibers elongate and thin fibers lyse. These results highlight how subtle differences in the diameter and prestrain of fibers could lead to dramatically different lytic susceptibilities. PMID:25714359

  9. Synchronized cell attachment triggered by photo-activatable adhesive ligands allows QCM-based detection of early integrin binding

    PubMed Central

    Iturri, Jagoba; García-Fernández, Luis; Reuning, Ute; García, Andrés J.; Campo, Aránzazu del; Salierno, Marcelo J.

    2015-01-01

    The Quartz Crystal Microbalance with dissipation (QCM-D) technique was applied to monitor and quantify integrin-RGD recognition during the early stages of cell adhesion. Using QCM-D crystals modified with a photo-activatable RGD peptide, the time point of presentation of adhesive ligand at the surface of the QCM-D crystal could be accurately controlled. This allowed temporal resolution of early integrin-RGD binding and the subsequent cell spreading process, and their separate detection by QCM-D. The specificity of the integrin-RGD binding event was corroborated by performing the experiments in the presence of soluble cyclicRGD as a competitor, and cytochalasin D as inhibitor of cell spreading. Larger frequency change in the QCM-D signal was observed for cells with larger spread area, and for cells overexpressing integrin αvβ3 upon stable transfection. This strategy enables quantification of integrin activity which, in turn, may allow discrimination among different cell types displaying distinct integrin subtypes and expression levels thereof. On the basis of these findings, we believe the strategy can be extended to other photoactivatable ligands to characterize cell membrane receptors activity, a relevant issue for cancer diagnosis (and prognosis) as other several pathologies. PMID:25825012

  10. Polypeptide micelles with dual pH activatable dyes for sensing cells and cancer imaging

    NASA Astrophysics Data System (ADS)

    Gong, Ping; Yang, Yueting; Yi, Huqiang; Fang, Shengtao; Zhang, Pengfei; Sheng, Zonghai; Gao, Guanhui; Gao, Duyang; Cai, Lintao

    2014-04-01

    pH is an important control parameter for maintenance of cell viability and tissue functions. pH monitoring provides valuable information on cell metabolic processes and the living environment. In this study, we prepared dual pH-sensitive, fluorescent dye-loaded polypeptide nanoparticles (DPNs) for ratiometric sensing of pH changes in living cells. DPNs contain two types of dyes: N-(rhodamine B) lactam cystamine (RBLC), an acid activatable fluorescent dye with increased fluorescence in an acidic environment, and fluorescein isothiocyanate (FITC), a base activatable fluorescent dye with enhanced fluorescence in an alkaline environment. Hence, DPNs exhibited a dual response signal with strong red fluorescence and weak green fluorescence under acidic conditions; in contrast, they showed strong green fluorescence and almost no red fluorescence under alkaline and neutral conditions. The favorable inverse pH responses of the two fluorescent dyes resulted in ratiometric pH determination for DPNs with an optimized pH-sensitive range of pH 4.5-7.5. Quantitative analysis of the intracellular pH of intact MCF-7 cells has been successfully demonstrated with our nanosensor. Moreover, single acid activatable fluorescent dye doped polypeptide nanoparticles that only contained RBLC can distinguish tumor tissue from normal tissue by monitoring the acidic extracellular environment.pH is an important control parameter for maintenance of cell viability and tissue functions. pH monitoring provides valuable information on cell metabolic processes and the living environment. In this study, we prepared dual pH-sensitive, fluorescent dye-loaded polypeptide nanoparticles (DPNs) for ratiometric sensing of pH changes in living cells. DPNs contain two types of dyes: N-(rhodamine B) lactam cystamine (RBLC), an acid activatable fluorescent dye with increased fluorescence in an acidic environment, and fluorescein isothiocyanate (FITC), a base activatable fluorescent dye with enhanced fluorescence

  11. Activatable 19F MRI nanoparticle probes for the detection of reducing environments.

    PubMed

    Nakamura, Tatsuya; Matsushita, Hisashi; Sugihara, Fuminori; Yoshioka, Yoshichika; Mizukami, Shin; Kikuchi, Kazuya

    2015-01-12

    (19)F magnetic resonance imaging (MRI) probes that can detect biological phenomena such as cell dynamics, ion concentrations, and enzymatic activity have attracted significant attention. Although perfluorocarbon (PFC) encapsulated nanoparticles are of interest in molecular imaging owing to their high sensitivity, activatable PFC nanoparticles have not been developed. In this study, we showed for the first time that the paramagnetic relaxation enhancement (PRE) effect can efficiently decrease the (19)F NMR/MRI signals of PFCs in silica nanoparticles. On the basis of the PRE effect, we developed a reduction-responsive PFC-encapsulated nanoparticle probe, FLAME-SS-Gd(3+) (FSG). This is the first example of an activatable PFC-encapsulated nanoparticle that can be used for in vivo imaging. Calculations revealed that the ratio of fluorine atoms to Gd(3+) complexes per nanoparticle was more than approximately 5.0×10(2), resulting in the high signal augmentation. PMID:25413833

  12. The role of ACTH and glucocorticoids in nonenzymatic fibrinolysis during immobilization stress in animals

    NASA Technical Reports Server (NTRS)

    Kudryashov, B. A.; Shapiro, F. B.; Lomovskaya, E. G.; Lyapina, L. A.

    1980-01-01

    The role of the altered hormonal status of an organism in the activation of the anticoagulative system during stress is investigated. The 30 minute immobilization stress was shown to raise significantly the nonenzymatic fibrinolytic activity of blood in rats. Combined with adrenocorticotropin (ACTH) the effect is still greater. Intravenous administration of 0.2 m1 0.01 percent solution of protamine sulphate prevented the nonenzymatic fibrinolysis induced by the stress. Administration of ACTH after protomine sulphate again raised the fibrinolysis. This suggests that ACTH stimulates the release of heparin.

  13. A Novel Serine Protease Secreted by Medicinal Maggots Enhances Plasminogen Activator-Induced Fibrinolysis

    PubMed Central

    van der Plas, Mariena J. A.; Andersen, Anders S.; Nazir, Sheresma; van Tilburg, Nico H.; Oestergaard, Peter R.; Krogfelt, Karen A.; van Dissel, Jaap T.; Hensbergen, Paul J.

    2014-01-01

    Maggots of the blowfly Lucilia sericata are used for the treatment of chronic wounds. As haemostatic processes play an important role in wound healing, this study focused on the effects of maggot secretions on coagulation and fibrinolysis. The results showed that maggot secretions enhance plasminogen activator-induced formation of plasmin and fibrinolysis in a dose- and time-dependent manner. By contrast, coagulation was not affected by secretions. Biochemical studies indicated that a novel serine protease within secretions, designated Sericase, cleaved plasminogen to several fragments. Recombinant Sericase degraded plasminogen leading amongst others to the formation of the mini-plasminogen like fragment Val454-plasminogen. In addition, the presence of a non-proteolytic cofactor in secretions was discovered, which plays a role in the enhancement of plasminogen activator-induced fibrinolysis by Sericase. We conclude from our in vitro studies that the novel serine protease Sericase, with the aid of a non-proteolytic cofactor, enhances plasminogen activator-induced fibrinolysis. PMID:24647546

  14. Effect of onion and garlic on blood coagulation and fibrinolysis in vitro.

    PubMed

    Nagda, K K; Ganeriwal, S K; Nagda, K C; Diwan, A M

    1983-01-01

    The effects of aqueous extracts of onion and garlic as well as of garlic oil were studied on the process of blood coagulation and fibrinolysis in vitro. Only onion was found to exhibit anti-coagulant and fibrinolytic activity while garlic extract as well as garlic oil were inactive. PMID:6885127

  15. The effect of exercise on coagulation and fibrinolysis factors in patients with peripheral arterial disease.

    PubMed

    Patelis, Nikolaos; Karaolanis, Georgios; Kouvelos, Georgios N; Hart, Collin; Metheiken, Sean

    2016-09-01

    Peripheral arterial disease is a widely prevalent atherosclerotic occlusive disorder. Symptoms commence with exercise-induced pain in the lower extremities, known as claudication. Despite the fact that exercise has been shown to improve fibrinolytic profile some patients, the effect of exercise on coagulation and fibrinolysis cascades in claudicants has not been comprehensively defined. Literature search in English language yielded 13 studies of exercise on claudicants, including 420 patients. Claudicants tend to have a higher coagulation activity at rest compared to healthy individuals, a trend that persists even after exercise. Post-exercise coagulation activity of claudicants is increased when compared to their respective baseline levels, but it is so in a non-consistent manner. From the available data, it has been suggested that claudicants have a functional and effective fibrinolytic mechanism in place, operating continuously at a relatively higher activity level compared to healthy individuals. Fibrinolysis seems to be activated by exercise; a positive outcome with a prolonged effect as shown by a few of the studies. A final conclusion whether coagulation or fibrinolysis activity is affected mostly by exercise type and intensity in claudicants could not be answered. All conclusions regarding the effect of exercise on the coagulation and fibrinolysis mechanisms should be taken under cautious consideration, due to the limited number of studies, the small number of patients and the different exercise strategies employed in each study. Further randomized studies with similar exercise protocols could provide safer conclusions in the future. PMID:27444152

  16. Effects of Hyperbaric and Decompression Stress on Blood Coagulation and Fibrinolysis: Comparison of Thromboelastography and Thromboelastometry.

    PubMed

    Peng, Henry T; Cameron, Bruce A; Rhind, Shawn G

    2016-05-01

    Hyperbaric and decompression stress from diving impairs blood coagulation and fibrinolysis. We hypothesized that thromboelastography (TEG) and rotational thromboelastometry (ROTEM) were suitable to characterize the effects of stress on global hemostatic profiles. We thus conducted a comparative study of the hyperbaric effects on human coagulation using TEG and ROTEM. Maximum clot strength (maximum amplitude [MA]) and clot lysis (lysis index at time 30 minutes [LI30]) were reduced as indicated by TEG MA and EXTEM LI30, respectively. The relative changes in coagulation and fibrinolysis by the hyperbaric effects of diving were indicated by reduced TEG reaction time R at 5 hours, MA at 24 hours postdive, and reduced EXTEM coagulation time at 15 minutes postdive as well as decreased fibrinolysis (EXTEM LI30) at all postdiving time points investigated. Comparison of the parameter values and the diving-induced changes in each parameter between TEG and ROTEM showed both differences and correlations. The discrepancies between the 2 systems may be due to the different assay reagents used. Future studies will seek to further elucidate the changes in blood coagulation and fibrinolysis following varying levels of hyperbaric and decompression stress. PMID:25616490

  17. H-type Dimer Formation of Fluorophores: A Mechanism for Activatable, in vivo Optical Molecular Imaging

    PubMed Central

    Ogawa, Mikako; Kosaka, Nobuyuki; Choyke, Peter L; Kobayashi, Hisataka

    2009-01-01

    In vivo molecular imaging with target-specific activatable “smart” probes, which only yield fluorescence at the intended target, enables sensitive and specific cancer detection because of high target to background ratios (TBR). Dimerization and fluorescence quenching has been shown to occur in concentrated aqueous solutions of various fluorophores. Here, we hypothesized that fluorophore dimerization and quenching after conjugation to targeting proteins can occur at low concentration, which is reasonable for in vivo imaging probes, because protein molecules can stabilize the fluorophore dimers based on physico-chemical interactions. This dimerization can be exploited as a mechanism for fluorescence activation. Rhodamine derivatives were conjugated to the cancer targeting molecules, avidin and trastuzumab, which target D-galactose receptor and HER2/neu antigen, respectively. After conjugation, a large proportion of R6G and TAMRA formed H-type dimers, even at low concentrations, but could be fully dequenched upon dissociation of the dimers to monomers. Lipophilicity was a potential factor in promoting H-dimer formation. To demonstrate the fluorescence activation effect during in vivo fluorescence endoscopic molecular imaging, a highly quenched probe, avidin-TAMRA or a minimally quenched probe, avidin-Alexa488 was administered into mice with ovarian metastases to the peritoneum. The tumors were clearly visualized with avidin-TAMRA, with low background fluorescence; in contrast, the background fluorescence was high for avidin-Alexa488. Thus, H-dimer formation as a mechanism of fluorescence quenching could be used to develop fluorescence activatable probes for in vivo molecular imaging. Effective activatable optical probes can be designed by focusing on the H-dimer formation of fluorophores. PMID:19480464

  18. Activatable iRGD-based peptide monolith: Targeting, internalization, and fluorescence activation for precise tumor imaging.

    PubMed

    Cho, Hong-Jun; Lee, Sung-Jin; Park, Sung-Jun; Paik, Chang H; Lee, Sang-Myung; Kim, Sehoon; Lee, Yoon-Sik

    2016-09-10

    A disulfide-bridged cyclic RGD peptide, named iRGD (internalizing RGD, c(CRGDK/RGPD/EC)), is known to facilitate tumor targeting as well as tissue penetration. After the RGD motif-induced targeting on αv integrins expressed near tumor tissue, iRGD encounters proteolytic cleavage to expose the CendR motif that promotes penetration into cancer cells via the interaction with neuropilin-1. Based on these proteolytic cleavage and internalization mechanism, we designed an iRGD-based monolithic imaging probe that integrates multiple functions (cancer-specific targeting, internalization and fluorescence activation) within a small peptide framework. To provide the capability of activatable fluorescence signaling, we conjugated a fluorescent dye to the N-terminal of iRGD, which was linked to the internalizing sequence (CendR motif), and a quencher to the opposite C-terminal. It turned out that fluorescence activation of the dye/quencher-conjugated monolithic peptide probe requires dual (reductive and proteolytic) cleavages on both disulfide and amide bond of iRGD peptide. Furthermore, the cleavage of the iRGD peptide leading to fluorescence recovery was indeed operative depending on the tumor-related angiogenic receptors (αvβ3 integrin and neuropilin-1) in vitro as well as in vivo. Compared to an 'always fluorescent' iRGD control probe without quencher conjugation, the dye/quencher-conjugated activatable monolithic peptide probe visualized tumor regions more precisely with lower background noise after intravenous injection, owing to the multifunctional responses specific to tumor microenvironment. All these results, along with minimal in vitro and in vivo toxicity profiles, suggest potential of the iRGD-based activatable monolithic peptide probe as a promising imaging agent for precise tumor diagnosis. PMID:27349354

  19. DNase-activatable fluorescence probes visualizing the degradation of exogenous DNA in living cells

    NASA Astrophysics Data System (ADS)

    Gong, Ping; Shi, Bihua; Zhang, Pengfei; Hu, Dehong; Zheng, Mingbin; Zheng, Cuifang; Gao, Duyang; Cai, Lintao

    2012-03-01

    This work presents a method to visualize the degradation of exogenous DNA in living cells using a novel type of activatable fluorescence imaging probe. Deoxyribonuclease (DNase)-activatable fluorescence probes (DFProbes) are composed of double strands deoxyribonucleic acid (dsDNA) which is labeled with fluorophore (ROX or Cy3) and quencher on the end of one of its strands, and stained with SYBR Green I. In the absence of DNase, DFProbes produce the green fluorescence signal of SYBR Green I. In the presence of DNase, SYBR Green I is removed from the DFProbes and the labeled fluorophore is separated from the quencher owing to the degradation of DFProbes by DNase, resulting in the decrease of the green fluorescence signal and the occurrence of a red fluorescence signal due to fluorescence resonance energy transfer (FRET). DNase in biological samples was detected using DFProbes and the fluorescence imaging in living cells was performed using DFprobe-modified Au nanoparticles. The results show that DFProbes have good responses to DNase, and can clearly visualize the degradation of exogenous DNA in cells in real time. The well-designed probes might be useful in tracing the dynamic changes of exogenous DNA and nanocarriers in vitro and in vivo.This work presents a method to visualize the degradation of exogenous DNA in living cells using a novel type of activatable fluorescence imaging probe. Deoxyribonuclease (DNase)-activatable fluorescence probes (DFProbes) are composed of double strands deoxyribonucleic acid (dsDNA) which is labeled with fluorophore (ROX or Cy3) and quencher on the end of one of its strands, and stained with SYBR Green I. In the absence of DNase, DFProbes produce the green fluorescence signal of SYBR Green I. In the presence of DNase, SYBR Green I is removed from the DFProbes and the labeled fluorophore is separated from the quencher owing to the degradation of DFProbes by DNase, resulting in the decrease of the green fluorescence signal and the

  20. Selective treatment and monitoring of disseminated cancer micrometastases in vivo using dual-function, activatable immunoconjugates

    PubMed Central

    Spring, Bryan Q.; Abu-Yousif, Adnan O.; Palanisami, Akilan; Rizvi, Imran; Zheng, Xiang; Mai, Zhiming; Anbil, Sriram; Sears, R. Bryan; Mensah, Lawrence B.; Goldschmidt, Ruth; Erdem, S. Sibel; Oliva, Esther; Hasan, Tayyaba

    2014-01-01

    Drug-resistant micrometastases that escape standard therapies often go undetected until the emergence of lethal recurrent disease. Here, we show that it is possible to treat microscopic tumors selectively using an activatable immunoconjugate. The immunoconjugate is composed of self-quenching, near-infrared chromophores loaded onto a cancer cell-targeting antibody. Chromophore phototoxicity and fluorescence are activated by lysosomal proteolysis, and light, after cancer cell internalization, enabling tumor-confined photocytotoxicity and resolution of individual micrometastases. This unique approach not only introduces a therapeutic strategy to help destroy residual drug-resistant cells but also provides a sensitive imaging method to monitor micrometastatic disease in common sites of recurrence. Using fluorescence microendoscopy to monitor immunoconjugate activation and micrometastatic disease, we demonstrate these concepts of “tumor-targeted, activatable photoimmunotherapy” in a mouse model of peritoneal carcinomatosis. By introducing targeted activation to enhance tumor selectively in complex anatomical sites, this study offers prospects for catching early recurrent micrometastases and for treating occult disease. PMID:24572574

  1. Activatable thermo-sensitive ICG encapsulated pluronic nanocapsules for temperature sensitive fluorescence tomography

    NASA Astrophysics Data System (ADS)

    Kwong, Tiffany C.; Nouizi, Farouk; Sampathkumaran, Uma; Zhu, Yue; Alam, Maksudul M.; Gulsen, Gultekin

    2015-03-01

    Fluorescent tomography has been hindered by poor tissue penetration and weak signal which results in poor spatial resolution and quantification accuracy. Recently, it has been reported that activatable temperature responsive fluorescent probes which respond to focused ultrasound heating can improve the resolution and quantification of fluorescent tomography in deep tissue. This has lead to a new imaging modality, "Temperature-modulated fluorescent tomography." This technique relies on activatable thermo-sensitive fluorescent nanocapsules for whose fluorescence quantum efficiency is temperature dependent. Within a 4-5° C temperature range, the fluorescent signal increase more than 10-fold. In this molecular probe, Indocyanine Green (ICG) is encapsulated inside the core of a thermo-reversible pluronic micelle. Here we show the fluorescence response and temperature range of the nanocapsules which have been optimized for a higher temperature range to be used for in vivo animal imaging. We report on the feasibility of these temperature-sensitive reversible nanocapsules for in vivo applications by studying the pharmacokinetics in a subcutaneous mouse tumor model in vivo.

  2. Hydrogen peroxide-activatable antioxidant prodrug as a targeted therapeutic agent for ischemia-reperfusion injury

    PubMed Central

    Lee, Dongwon; Park, Seunggyu; Bae, Soochan; Jeong, Dahee; Park, Minhyung; Kang, Changsun; Yoo, Wooyoung; Samad, Mohammed A.; Ke, Qingen; Khang, Gilson; Kang, Peter M.

    2015-01-01

    Overproduction of hydrogen peroxide (H2O2) causes oxidative stress and is the main culprit in the pathogenesis of ischemia/reperfusion (I/R) injury. Suppression of oxidative stress is therefore critical in the treatment of I/R injury. Here, we report H2O2-activatable antioxidant prodrug (BRAP) that is capable of specifically targeting the site of oxidative stress and exerting anti-inflammatory and anti-apoptotic activities. BRAP with a self-immolative boronic ester protecting group was designed to scavenge H2O2 and release HBA (p-hydroxybenzyl alcohol) with antioxidant and anti-inflammatory activities. BRAP exerted potent antioxidant and anti-inflammatory activity in lipopolysaccharide (LPS)- and H2O2-stimulated cells by suppressing the generation of ROS and pro-inflammatory cytokines. In mouse models of hepatic I/R and cardiac I/R, BRAP exerted potent antioxidant, anti-inflammatory and anti-apoptotic activities due to the synergistic effects of H2O2-scavenging boronic esters and therapeutic HBA. In addition, administration of high doses of BRAP daily for 7 days showed no renal or hepatic function abnormalities. Therefore BRAP has tremendous therapeutic potential as H2O2-activatable antioxidant prodrug for the treatment of I/R injuries. PMID:26563741

  3. Systemic fibrinolysis through intraosseous vascular access in ST-segment elevation myocardial infarction.

    PubMed

    Ruiz-Hornillos, Pedro José; Martínez-Cámara, Fernando; Elizondo, Mercedes; Jiménez-Fraile, José Antonio; Del Mar Alonso-Sánchez, Maria; Galán, Dolores; García-Rubira, Juan Carlos; Macaya, Carlos; Ibanez, Borja

    2011-06-01

    In emergency situations, intraosseous cannulation represents an alternative route of vascular access when peripheral vein insertion is difficult. We present the first documented case of intraosseous systemic fibrinolysis in a patient with ST-segment elevation myocardial infarction. In this case, repetitive episodes of ventricular fibrillation occurred soon after first contact with emergency care providers. Given that the patient had difficult peripheral venous access, an intraosseous catheter was inserted. Fibrinolytics and antiarrhythmic drugs were administered though this line, resulting in resolution of coronary ischemia and electrical instability, without complications. Intraosseous cannulation represents a novel route for administration of systemic fibrinolysis in cases of difficult peripheral venous access in the out-of-hospital setting. PMID:20947209

  4. [Puncture aspiration and local fibrinolysis in the surgery of primary non-traumatic intracranial hemorrhages].

    PubMed

    Krylov, V V; Burov, S A; Dash'ian, V G; Galankina, I E

    2008-01-01

    A possibility of evacuation of primary non-traumatic intracranial hematomas with less traumatic effect using puncture aspiration and local fibrinolysis has been studied in 73 patients aged 23-69 years. It has been shown that this method allows an effective (up to 95% of initial volume) evacuation of hypertensive hematomas in most patients. The evacuation of hemorrhage is accompanied by the significant regress of movement disorders already in the early post-operative period that promotes shortening of treatment time in patients with hemorrhage stroke. The positive changes of neurological status are supported by the morphological data on the induction of reparative processes in the perifocal brain tissue against the background of focal fibrinolysis. The reduction of post-operative fatal cases (from 35 to 23%) allows a recommendation of the method described in surgery of hypertensive hemorrhages. PMID:19008848

  5. Acute phase treatment of venous thromboembolism: advanced therapy. Systemic fibrinolysis and pharmacomechanical therapy.

    PubMed

    Konstantinides, Stavros V; Wärntges, Simone

    2015-06-01

    Venous thromboembolism, which encompasses deep-vein thrombosis and acute pulmonary embolism (PE), represents a major contributor to global disease burden worldwide. For patients who present with cardiogenic shock or persistent hypotension (acute high-risk PE), there is consensus that immediate reperfusion treatment applying systemic fibrinolysis or, in the case of a high bleeding risk, surgical or catheter-directed techniques, is indicated. On the other hand, for the large, heterogeneous group of patients presenting without overt haemodynamic instability, the indications for advanced therapy are less clear. The recently updated guidelines of the European Society of Cardiology emphasise the importance of clinical prediction rules in combination with imaging procedures (assessment of right ventricular function) and laboratory biomarkers (indicative of myocardial stress or injury) for distinguishing between an intermediate and a low risk for an adverse early outcome. In intermediate-high-risk PE defined by the presence of both right ventricular dysfunction on echocardiography (or computed tomography) and a positive troponin (or natriuretic peptide) test, the bleeding risks of full-dose fibrinolytic treatment have been shown to outweigh its potential clinical benefits unless clinical signs of haemodynamic decompensation appear (rescue fibrinolysis). Recently published trials suggest that catheter-directed, ultrasound-assisted, low-dose local fibrinolysis may provide an effective and particularly safe treatment option for some of these patients. PMID:25789580

  6. Reduced platelet-mediated and enhanced leukocyte-mediated fibrinolysis in experimentally induced diabetes in rats

    SciTech Connect

    Winocour, P.D.; Colwell, J.A.

    1985-05-01

    Studies of fibrinolytic activity in diabetes mellitus have produced conflicting results. This may be a result of methodologic insensitivity or of variable contributions of the different blood components to whole blood fibrinolysis. To explore these two possibilities, the authors used a sensitive solid-phase radiometric assay to examine the fibrinolytic activity of whole blood, platelet-rich plasma, leukocytes, and platelet- and leukocyte-poor plasma prepared from control rats and rats with streptozocin-induced diabetes at various times after induction of diabetes. Fibrinolytic activity of whole blood from diabetic rats after 7 days was significantly reduced, and remained reduced after longer durations of diabetes up to 28 days. Platelet-rich plasma from diabetic rats had decreased fibrinolytic activity, which followed the same time course of changes as in whole blood. The platelet contribution to whole blood fibrinolysis was further reduced in vivo after 14 days of diabetes by a reduced whole blood platelet count. In contrast, fibrinolytic activity of leukocytes from diabetic rats became enhanced after 7 days of diabetes. After 49 days of diabetes, the whole blood leukocyte count was reduced, and in vivo would offset the enhanced activity. Plasma fibrinolytic activity was small compared with that of whole blood and was unaltered in diabetic rats. The authors conclude that altered platelet function contributes to decreased fibrinolytic activity of whole blood in diabetic rats, and that this may be partially offset by enhanced leukocyte-mediated fibrinolysis.

  7. [Characteristics of the indicators of the blood coagulation and fibrinolysis systems in the pre-clinical stage of ischemic heart disease].

    PubMed

    Andreenko, G V; Panchenko, V M; Lisina, A N; Liutova, L V

    1978-10-01

    Signs of dysfunction of the coagulation system and fibrinolysis were determined in 45 healthy young individuals who had such risk factors in relation to ischemic heart disease as arterial hypertension, hypercholesterolemia, smoking, aggravated heredity, permanent emotional overstress, etc. These signs were manifested by a tendency to augmentation of blood coagulation and compensatory activation of fibrinolysis. Ischemic-type changes were detected on the ECG after a physical load. It is assumed that dysfunction of the coagulation system and fibrinolysis is an additional risk factor in relation to ischemic heart disease, while derangement of compensatory fibrinolysis tension with the subsequent tension of its components may lead to the development of coronary thrombosis. PMID:713256

  8. Iron and carbon monoxide attenuate Crotalus atrox venom-enhanced tissue-type plasminogen activator-initiated fibrinolysis.

    PubMed

    Nielsen, Vance G; Boyer, Leslie V; Matika, Ryan W; Amos, Quinlan; Redford, Daniel T

    2016-07-01

    In addition to degrading fibrinogen as a source of consumptive coagulopathy, rattlesnake venom has also been demonstrated to enhance fibrinolysis and degrade alpha-2-antiplasmin. The goals of this investigation was to characterize the kinetic fibrinolytic profile of Crotalus atrox venom in the absence and presence of tissue-type plasminogen activator (tPA), and to also ascertain if iron and carbon monoxide (CO, a positive modulator of alpha-2-antiplasmin) could attenuate venom-enhanced fibrinolysis. Utilizing thrombelastographic methods, the coagulation and fibrinolytic kinetic profiles of human plasma exposed to C. atrox venom (0-2 μg/ml) were determined in the absence or presence of tPA (0-100 IU/ml). Then, either separately or in combination, plasma was exposed to iron (ferric chloride, 10 μmol/l) or CO (carbon monoxide-releasing molecule-2, 100 μmol/l) prior to incubation with venom; the plasma sample was subsequently subjected to thrombelastographic analysis with addition of tPA. Venom exposure in the absence of tPA did not result in detectable fibrinolysis. In the presence of tPA, venom markedly enhanced fibrinolysis. Iron and CO, markedly attenuated venom enhancement of fibrinolysis. C. atrox venom enhances tPA-mediated fibrinolysis, and interventions that enhance/protect alpha-2-antiplasmin activity significantly attenuate venom-enhanced fibrinolysis. Future preclinical investigation is required to determine if iron and CO can attenuate venom-mediated degradation of alpha-2-antiplasmin-dependent fibrinolytic resistance. PMID:26575490

  9. Theranostic nanoparticles for enzyme-activatable fluorescence imaging and photodynamic/chemo dual therapy of triple-negative breast cancer

    PubMed Central

    Choi, Jaehee; Kim, Hyunjin

    2015-01-01

    Background Triple-negative breast cancer (TNBC) is a highly diverse group of cancers characterized by tumors that does not express estrogen and progesterone receptors, as well as human epidermal growth factor receptor 2 (HER2) gene expression. TNBC is associated with poor prognosis due to high rate of recurrence and distance metastasis, lack of response to hormonal or HER2-targeted therapies, and partial response to chemotherapy. Hence, development of new therapeutic strategies to overcome such limitations is of great importance. Here we describe the application of photosensitizer-conjugated and camptothecin (CPT)-encapsulated hyaluronic acid (HA) nanoparticles as enzyme-activatable theranostic nanoparticles (EATNP) for near-infrared (NIR) fluorescence imaging and photodynamic/chemo dual therapy of TNBC. Methods For the preparation of EATNPs, chlorin e6 (Ce6), a second generation photosensitizer, was covalently conjugated to a monomethoxy poly(ethylene glycol)-grafted HA backbone. Ce6-conjugated HA (Ce6-HA) formed self-assembled nanoparticles (i.e., Ce6-HA NPs) in an aqueous solution. Subsequently, CPT, a topoisomerase 1 inhibitor with remarkable anticancer efficacy but with low water solubility, was encapsulated inside the hydrophobic core of Ce6-HA NPs thereby forming EATNPs. Results Fluorescence and singlet oxygen generation (SOG) of EATNPs are quenched in its native state. Treatment of EATNPs with hyaluronidase (HAdase) induces enzyme concentration-dependent activation of NIR fluorescence and SOG. Moreover, HAdase-mediated degradation of the nanoparticles also triggers the release of CPT from the EATNPs. In vitro confocal microscopy and cytotoxicity tests confirmed that EATNPs were efficiently introduced into MDA-MB-231 TNBC cell line, thereby inducing better cytotoxicity than that by free CPT. Additional light irradiation onto the EATNP-treated cells significantly increased therapeutic efficacy in TNBC, which indicates that EATNP plays an important role in

  10. Efficacy and safety of a routine early invasive strategy in relation to time from symptom onset to fibrinolysis (a subgroup analysis of TRANSFER-AMI).

    PubMed

    Russo, Juan J; Goodman, Shaun G; Cantor, Warren J; Tan, Mary K; Borgundvaag, Bjug; Fitchett, David; Džavík, Vladimír; Yan, Raymond T; Graham, John J; Mehta, Shamir R; Yan, Andrew T

    2015-04-15

    The aim of this study was to assess the efficacy and safety of an early invasive strategy post-fibrinolysis in relation to time from symptom onset to fibrinolysis in patients with ST-elevation myocardial infarction (STEMI). The Trial of Routine Angioplasty and Stenting after Fibrinolysis to Enhance Reperfusion in Acute Myocardial Infarction (TRANSFER-AMI) randomized 1,059 patients receiving fibrinolysis for STEMI to an early invasive strategy versus standard therapy. The primary end point was the composite of death, reinfarction, recurrent ischemia, new or worsening heart failure, or cardiogenic shock at 30 days. In this post hoc subgroup analysis, we examined the effect of an early invasive strategy on efficacy and safety outcomes after stratification by time from symptom onset to fibrinolysis (<2 or ≥2 hours). Of 1,059 patients in TRANSFER-AMI, 557 (53%) received fibrinolysis <2 hours and 502 (47%) ≥2 hours after symptom onset. Compared to patients who received fibrinolysis within 2 hours of symptoms, patients who received fibrinolysis ≥2 hours after symptom onset had higher Global Registry of Acute Coronary Events risk scores (median 127 vs 122, p = 0.004). The effect of an early invasive strategy did not differ between symptom-to-fibrinolysis time strata for the primary efficacy end point (p-heterogeneity = 0.67), 30-day mortality, the composite of death or reinfarction at 30 days, 6 months, or 1 year, or bleeding (all p-heterogeneity >0.40). In conclusion, the efficacy and safety of an early invasive strategy in patients undergoing fibrinolysis for STEMI do not vary in relation to time (<2 or ≥2 hours) from symptom onset to fibrinolysis. PMID:25711435

  11. Cucurbit[8]uril Regulated Activatable Supramolecular Photosensitizer for Targeted Cancer Imaging and Photodynamic Therapy.

    PubMed

    Wang, Xiao-Qiang; Lei, Qi; Zhu, Jing-Yi; Wang, Wen-Jing; Cheng, Qian; Gao, Fan; Sun, Yun-Xia; Zhang, Xian-Zheng

    2016-09-01

    Activatable photosensitizers (aPSs) have emerged as promising photodynamic therapy (PDT) agents for simultaneous imaging and selective ablation of cancer. However, traditional synthetic aPSs are limited by complex design and tedious synthesis. Here, aPS regulated by cucurbit[8]uril (CB[8]) for targeted cancer imaging and PDT is reported. This system is based on the host-guest interaction between biotinylated toluidine blue (TB-B) and CB[8] to form 2TB-B@CB[8]. Moreover, a facile strategy to turn off/on the fluorescence and photodynamic activity of TB-B is developed through the reversible assembly/disassembly of 2TB-B@CB[8]. This established system can achieve selective accumulation in tumor, light-up cancer imaging, and enhanced anticancer behavior. Therefore, this work provides a novel and promising strategy for the aPS build via simple and facile regulation of supramolecular chemistry. PMID:27513690

  12. Sensitive and selective tumor imaging with novel and highly activatable fluorescence strategies

    NASA Astrophysics Data System (ADS)

    Urano, Yasuteru

    2008-02-01

    Nowadays, several tumor imaging modalities such as MRI, PET and fluorescence imaging techniques have been extensively investigated. One of the central problems associated with these conventional tumor-targeted imaging methods, however, is the fact that the signal contrast between tumor and surrounding tissues relies on the efficient targeting to the tumor and the rapid sequestration or excretion of unbound agent. Among these modalities, only fluorescence imaging technique has a significant feature, in that great signal activation could be achieved which potentially leads to the selective imaging of cancer with higher tumor-to-background ratio. In this symposium, I will present some examples of fluorescence cancer imaging based on highly activatable strategies with using precisely designed novel fluorescence probes. Recently, we developed highly sensitive fluorescence probes for β-galactosidase which is applicable for living cell system. By utilizing these probes, we could establish a novel and highly activatable strategy for sensitive and selective optical imaging of imbedded tumor in the peritoneum. We took a two step procedure in that a lectin is used to localize β-galactosidase to cancer cells as an activating enzyme, and subsequent administration of a highly-sensitive fluorescence probe for the enzyme have afforded remarkable fluorescence activation selectively in tumor mass. Since the tumor-targeted enzyme can catalyze numerous substrate turnovers, a great number of fluorescent molecules could be produced and hence the rapid and sensitive detection of tumor in vivo with high tumor-to-background ratio could be achieved. Moreover, the consequent close-up investigation using fluorescence microscopy revealed that cancer microfoci as small as 200 μm could be successfully visualized.

  13. [Local fibrinolysis in surgical treatment of non-traumatic intracranial hemorrhages].

    PubMed

    Krylov, V V; Burov, S A; Dash'ian, V G; Galankina, I E

    2013-01-01

    More than 70% of hypertensive hemorrhages are located in deep brain structures. The removal of such hematomas using encephalotomy is accompanied by additional cerebral trauma and often results in unsatisfactory outcomes. The puncture aspiration with local fibrinolysis is one of the minimal invasive methods for treatment of intracerebral hematomas (ICH). The puncture and aspiration of liquid part of ICH (not more than 20% of ICH volume) is performed via small burr hole. Afterward the catheter is placed into ICH cavity and fibrinolytic is injected via this catheter in postoperative period for lysis of ICH solid part. The lysed blood is aspirated within 1-4 days. The last generations of fibrinolytics are very effective concerning intensity of blood clot lysis and practically have no systematic effect on blood coagulation system during their local usage. Morphological examinations showed that usage of fibrinolysis leads to formation of smaller cysts in the region of former hematoma as well as reparative processes in perihemorrhagical zone are expressed better comparing with treatment methods without usage of fibrinolytics. The morphological pattern is also confirmed by clinical signs of neurological deficit regress corresponding to damage focus. We operated 124 patients with parenchymal hemorrhages and 28 patients with intraventricular hemorrhages using described minimally invasive method at the base of Scientific Research Institute of Emergency Care n.a. N. V. Sklifosovsky. The applied method allowed decreasing lethality from 35% to 21% among patients with parenchymal ICH and from 98% to 48%--among patients with ventricular hemotamponade underwent usage of ventricular drainage combined with local fibrinolysis. PMID:24340958

  14. Prostate Cancer-Associated Disseminated Intravascular Coagulation with Excessive Fibrinolysis Treated with Degarelix

    PubMed Central

    Ong, Shawn Y.; Taverna, Josephine; Jokerst, Clint; Enzler, Thomas; Hammode, Emad; Rogowitz, Elisa; Green, Myke R.; Babiker, Hani M.

    2015-01-01

    Disseminated intravascular coagulation (DIC) with excessive fibrinolysis (XFL) is a rare and acute life-threatening variant of DIC in patients with prostate cancer. Patients present with coagulopathy, hypofibrinogenemia, and systemic bleeding. We describe a case of DIC XFL caused by prostate cancer (PC) successfully treated with a single injection of degarelix, a gonadotropin-releasing hormone (GnRH) receptor antagonist. This led to prompt control of the patient's coagulopathy within ten days of treatment. Our case highlights features of this rare and devastating hemorrhagic complication of PC along with a fast-acting and effective therapeutic drug option. PMID:26613055

  15. Chemical synthesis of a two-photon-activatable chemokine and photon-guided lymphocyte migration in vivo

    PubMed Central

    Chen, Xin; Tang, Shan; Zheng, Ji-Shen; Zhao, Ruozhu; Wang, Zhi-Peng; Shao, Wen; Chang, Hao-Nan; Cheng, Jing-Yuan; Zhao, Hui; Liu, Lei; Qi, Hai

    2015-01-01

    Chemokine-guided lymphocyte positioning in tissues is crucial for normal operation of the immune system. Direct, real-time manipulation and measurement of single-cell responses to chemokines is highly desired for investigating the cell biology of lymphocyte migration in vivo. Here we report the development of the first two-photon-activatable chemokine CCL5 through efficient one-pot total chemical synthesis in milligram scale. By spatiotemporally controlled photoactivation, we show at the single-cell level that T cells perceive the directional cue without relying on PI3K activities, which are nonetheless required for persistent migration over an extended period of time. By intravital imaging, we demonstrate artificial T-cell positioning in cutaneous tissues and lymph nodes. This work establishes a general strategy to develop high-quality photo-activatable protein agents through tailor-designed caging of multiple residues and highlights the potential of photo-activatable chemokines for understanding and potential therapeutic manipulation of cell positioning and position-controlled cell behaviours in vivo. PMID:26008852

  16. Fluorescence in vivo imaging of live tumor cells with pH-activatable targeted probes via receptor-mediated endocytosis

    NASA Astrophysics Data System (ADS)

    Asanuma, Daisuke; Urano, Yasuteru; Nagano, Tetsuo; Hama, Yukihiro; Koyama, Yoshinori; Kobayashi, Hisataka

    2009-02-01

    One goal of molecular imaging is to establish a widely applicable technique for specific detection of tumors with minimal background. Here, we achieve specific in vivo tumor visualization with a newly-designed "activatable" targeted fluorescence probe. This agent is activated after cellular internalization by sensing the pH change in the lysosome. Novel acidic pH-activatable probes based on the BODIPY fluorophore were synthesized, and then conjugated to a cancer-targeting monoclonal antibody, Trastuzumab, or galactosyl serum albumin (GSA). As proof of concept, ex and in vivo imaging of two different tumor mouse models was performed: HER2-overexpressed lung metastasis tumor with Trastuzumab-pH probe conjugates and lectin-overexpressed i.p. disseminated tumor with GSA-pH probe conjugates. These pH-activatable targeted probes were highly specific for tumors with minimal background signal. Because the acidic pH in lysosomes is maintained by the energy-consuming proton pump, only viable cancer cells were successfully visualized. Furthermore, this strategy was also applied to fluorescence endoscopy in tumor mouse models, resulting in specific visualization of tumors as small as submillimeter in size that could hardly detected by naked eyes because of their poor contrast against normal tissues. The design concept can be widely adapted to cancer-specific cell-surface-targeting molecules that result in cellular internalization.

  17. Shrimp Alpha-2-Macroglobulin Prevents the Bacterial Escape by Inhibiting Fibrinolysis of Blood Clots

    PubMed Central

    Chaikeeratisak, Vorrapon; Somboonwiwat, Kunlaya; Tassanakajon, Anchalee

    2012-01-01

    Proteomic analysis of the hemocytic proteins of Penaeus monodon (Pm) has previously shown that alpha-2-macroglobulin (A2M) was among the proteins that showed substantially altered expression levels upon Vibrio harveyi infection. Therefore, in this study its potentially important role in the response of shrimp to bacterial infection was further characterized. The yeast two-hybrid system revealed that the receptor binding domain of PmA2M interacted with the carboxyl-terminus of one or both of the transglutaminase type II isoforms, which are key enzymes involved in the shrimp clotting system. In accord with this, PmA2M was found to be localized on the extracellular blood clots and to colocalize with clottable proteins. RNA interference (RNAi)-mediated knockdown of A2M transcript levels reduced the PmA2M transcript levels (∼94%) and significantly reduced the bacterial seizing ability of the clotting system, resulting in an up to 3.3-fold higher number of V. harveyi that systemically disseminated into the circulatory system at 5 min post-infection before subsequent clearance by the immune system. Furthermore, an appearance of PmA2M depleted clots in the presence of V. harveyi strikingly demonstrated fibrinolysis zones surrounding the bacteria. This study provides the first evidence of the vital role of PmA2M in enhancing bacterial sequestration by protecting blood clots against fibrinolysis. PMID:23082160

  18. Virulence Potential of Activatable Shiga Toxin 2d–Producing Escherichia coli Isolates from Fresh Produce

    PubMed Central

    Melton-Celsa, Angela R.; O'Brien, Alison D.; Feng, Peter C. H.

    2016-01-01

    Shiga toxin (Stx)–producing Escherichia coli (STEC) strains are food- and waterborne pathogens that are often transmitted via beef products or fresh produce. STEC strains cause both sporadic infections and outbreaks, which may result in hemorrhagic colitis and hemolytic uremic syndrome. STEC strains may elaborate Stx1, Stx2, and/or subtypes of those toxins. Epidemiological evidence indicates that STEC that produce subtypes Stx2a, Stx2c, and/or Stx2d are more often associated with serious illness. The Stx2d subtype becomes more toxic to Vero cells after incubation with intestinal mucus or elastase, a process named “activation.” Stx2d is not generally found in the E. coli serotypes most commonly connected to STEC outbreaks. However, STEC strains that are stx2d positive can be isolated from foods, an occurrence that gives rise to the question of whether those food isolates are potential human pathogens. In this study, we examined 14 STEC strains from fresh produce that were stx2d positive and found that they all produced the mucus-activatable Stx2d and that a subset of the strains tested were virulent in streptomycin-treated mice. PMID:26555533

  19. Virulence Potential of Activatable Shiga Toxin 2d-Producing Escherichia coli Isolates from Fresh Produce.

    PubMed

    Melton-Celsa, Angela R; O'Brien, Alison D; Feng, Peter C H

    2015-11-01

    Shiga toxin (Stx)-producing Escherichia coli (STEC) strains are food- and waterborne pathogens that are often transmitted via beef products or fresh produce. STEC strains cause both sporadic infections and outbreaks, which may result in hemorrhagic colitis and hemolytic uremic syndrome. STEC strains may elaborate Stx1, Stx2, and/or subtypes of those toxins. Epidemiological evidence indicates that STEC that produce subtypes Stx2a, Stx2c, and/or Stx2d are more often associated with serious illness. The Stx2d subtype becomes more toxic to Vero cells after incubation with intestinal mucus or elastase, a process named "activation." Stx2d is not generally found in the E. coli serotypes most commonly connected to STEC outbreaks. However, STEC strains that are stx2d positive can be isolated from foods, an occurrence that gives rise to the question of whether those food isolates are potential human pathogens. In this study, we examined 14 STEC strains from fresh produce that were stx2d positive and found that they all produced the mucus-activatable Stx2d and that a subset of the strains tested were virulent in streptomycin-treated mice. PMID:26555533

  20. Activatable Ferritin Nanocomplex for Real-Time Monitoring of Caspase-3 Activation during Photodynamic Therapy.

    PubMed

    Wang, Jingjing; Zhang, Liwen; Chen, Minglong; Gao, Shi; Zhu, Lei

    2015-10-21

    One mechanism of photodynamic therapy (PDT) for the ablation of tumors is to induce apoptosis. Visualization of apoptosis during PDT in real-time is of great benefit for predicting and evaluating therapeutic outcomes. Herein, we engineered a highly stable and sensitive caspase-3 ferritin activatable probe (FABP/ZnPc) for simultaneous delivery of a photosensitizer (ZnPc) and real-time visualization of apoptosis during PDT. Upon near-infrared (NIR) light irradiation, ZnPc becomes active and initiates apoptosis, upon which the outer layer of the FABP/ZnPc is degraded by the apoptotic marker, caspase-3, to boost strong fluorescent signals, ultimately allowing real-time imaging of apoptosis. Our results demonstrate the utility of FABP/ZnPc as a tool for PDT and simultaneous imaging of caspase-3 activation in vitro and in vivo. Overall, the ability of FABP/ZnPc to image apoptosis during PDT will not only facilitate optimizing and personalizing the PDT strategy but is also important for understanding the mechanisms of PDT. PMID:26388178

  1. CpG expedites regression of local and systemic tumors when combined with activatable nanodelivery.

    PubMed

    Kheirolomoom, Azadeh; Ingham, Elizabeth S; Mahakian, Lisa M; Tam, Sarah M; Silvestrini, Matthew T; Tumbale, Spencer K; Foiret, Josquin; Hubbard, Neil E; Borowsky, Alexander D; Murphy, William J; Ferrara, Katherine W

    2015-12-28

    Ultrasonic activation of nanoparticles provides the opportunity to deliver a large fraction of the injected dose to insonified tumors and produce a complete local response. Here, we evaluate whether the local and systemic response to chemotherapy can be enhanced by combining such a therapy with locally-administered CpG as an immune adjuvant. In order to create stable, activatable particles, a complex between copper and doxorubicin (CuDox) was created within temperature-sensitive liposomes. Whereas insonation of the CuDox liposomes alone has been shown to produce a complete response in murine breast cancer after 8 treatments of 6 mg/kg delivered over 4 weeks, combining this treatment with CpG resolved local cancers within 3 treatments delivered over 7 days. Further, contralateral tumors regressed as a result of the combined treatment, and survival was extended in systemic disease. In both the treated and contralateral tumor site, the combined treatment increased leukocytes and CD4+ and CD8+ T-effector cells and reduced myeloid-derived suppressor cells (MDSCs). Taken together, the results suggest that this combinatorial treatment significantly enhances the systemic efficacy of locally-activated nanotherapy. PMID:26471394

  2. Optimal dye-quencher pairs for the design of an "activatable" nanoprobe for optical imaging.

    PubMed

    Simard, Bryan; Tomanek, Boguslaw; van Veggel, Frank C J M; Abulrob, Abedelnasser

    2013-10-01

    Optical imaging offers high sensitivity and portability at low cost. The design of an optimal "activatable" imaging agent could greatly decrease the background noise and increase specificity of the signal. Five different molecules have been used to quench basal fluorescence of an enzyme substrate labeled with Cy5, Cy5.5 or IR800 at a distance of 8 amino acids (32 Å): a 6 nm gold nanoparticle (NP), a 20 nm and a 30 nm iron oxide (FeO) NP, the black hole quencher BHQ-3 and the IRdye quencher QC-1. The quenching efficiencies were 99% for QC1-IR800, 98% for QC1-Cy5.5, 96% for 30 nm FeO NP-Cy5.5, 89% for BHQ3-Cy5, 84% for BHQ3-Cy5.5, 77-90% for 6 nm gold NP-Cy5.5, depending on the number of dyes around the NP, 79% for 20 nm FeO NP-Cy5.5 and 77% for Cy5.5-Cy5. Signal activation upon cleavage by the matrix metalloproteinase MMP9 was proportional to the quenching efficiencies, ranging from 3-fold with Cy5.5-Cy5 to 67-fold with QC1-IR800. This independent work reports on the properties of the dyes and quenchers explaining the superior performance of QC-1 and 30 nm FeO NPs. PMID:23892541

  3. An Activatable Theranostic Nanomedicine Platform Based on Self-Quenchable Indocyanine Green-Encapsulated Polymeric Micelles.

    PubMed

    Liu, Lanxia; Ma, Guilei; Zhang, Chao; Wang, Hai; Sun, Hongfan; Wang, Chun; Song, Cunxian; Kong, Deling

    2016-06-01

    Self-quenchable indocyanine green (ICG)-encapsulated micelles with folic acid (FA)-targeting specificity (FA-ICG-micelles) were developed for biologically activatable photodynamic theranostics. FA-ICG-micelles were successfully prepared using the thin-film hydration method, which allows ICG to be encapsulated with a high drug loading that induces an efficient ICG-based quenched state. FA-ICG-micelles are initially in the "OFF" state with no fluorescence signal or phototoxicity, but they become highly fluorescent and phototoxic in cellular degradative environments. Importantly, via folate receptor-mediated endocytosis, the FA targeting of FA-ICG-micelles enhanced intracellular uptake and photodynamic therapy (PDT) efficacy. Systematic administration of FA-ICG-micelles to folate receptor-positive tumor-bearing mice elicited prolonged blood circulation, enhanced tumor accumulation and improved therapeutic efficiency compared to free ICG. Therefore, based on the FA-targeted specificity and switchable photoactivity, FA-ICG-micelles have potential for photodynamic theranostics in cancer. PMID:27319216

  4. Non-invasive manipulation of Drosophila behavior by two-photon excited red-activatable channelrhodopsin

    PubMed Central

    Hsiao, Po-Yen; Tsai, Chia-Lun; Chen, Ming-Chang; Lin, Yen-Yin; Yang, Shang-Da; Chiang, Ann-Shyn

    2015-01-01

    Scattering and absorption limit light penetration through inhomogeneous tissue. To reduce scattering, biochemists have shifted the wavelengths of excitation light for optogenetic actuators and fluorescent proteins to the orange-red range, while physicists have developed multiphoton technologies for deep tissue stimulation. We have built a rapid multiphoton spectroscopic screening system of genetically encoded red-activatable channelrhodopsin (ReaChR), and considered specific behaviors in transgenic Drosophila melanogaster as readouts to optimize the laser parameters for two-photon optogenetic activation. A wavelength-tunable optical parametric amplifier was adopted as the major light source for widefield two-photon excitation (TPE) of ReaChR. Our assays suggest that the optimized TPE wavelength of ReaChR is 1250 nm. Exploiting its capacity for optogenetic manipulation to induce macroscopic behavioral change, we realized rapid spectroscopic screening of genetically encoded effectors or indicators in vivo, and used modulation of ReaChR in the fly as a successful demonstration of such a system. PMID:26601000

  5. Southern copperhead venom enhances tissue-type plasminogen activator induced fibrinolysis but does not directly lyse human plasma thrombi.

    PubMed

    Nielsen, Vance G

    2016-07-01

    In addition to degrading fibrinogen as a source of consumptive coagulopathy, purified fractions of southern copperhead (Agkistrodon contortrix contortrix; A. c. contortrix) venom has been demonstrated to enhance fibrinolysis. The goal of this investigation was to characterize the kinetic fibrinolytic profile of A. c. contortrix venom in the absence and presence of tissue-type plasminogen activator (tPA) to determine if intact venom had tPA independent fibrinolytic properties. Utilizing thrombelastographic methods, the coagulation and fibrinolytic kinetic profiles of human plasma exposed to A. c. contortrix venom (0-6 μg/ml) were determined in the absence or presence of tPA (0-100 IU/ml). Then, plasma was exposed to 0-6 μg/ml of venom without tPA added and coagulation observed for 3 h. Venom significantly prolonged the onset of coagulation, decreased the velocity of thrombus growth but did not significantly decrease clot strength. In the presence of tPA, venom significantly decreased clot strength, shortened the time of onset of fibrinolysis, decreased clot lysis time but did not significantly affect the maximum rate of lysis. Lastly, while venom exposure in the absence of tPA significantly prolonged the onset of coagulation and decreased the velocity of clot growth, venom exposure did not result in detectable fibrinolysis over the 3 h observation period. A. c. contortrix venom enhances tPA mediated fibrinolysis by degrading plasma coagulation kinetics. Intact A. c. contortrix venom does not possess sufficient fibrinolytic activity to cause fibrinolysis in human plasma at the concentration tested. PMID:26407681

  6. Plasminogen-independent fibrinolysis by proteases produced by transformed chick embryo fibroblasts.

    PubMed Central

    Chen, L B; Buchanan, J M

    1975-01-01

    The fibrinolytic activity of proteases secreted by chick embryo fibroblasts infected with Rous sarcoma virus was studied by use of a procedure in which a fibrin clot was formed with highly purified fibrinogen and thrombin above the cell layer. This procedure results in the formation of fibrin that is apparently a more suitable substrate for studies on fibrinolysis than is fibrin prepared by other methods. Since neither plasminogen nor serum were included in the assay system in the present studies, the fibrinolytic activity observed cannot be ascribed to the conversion of the plasminogen in serum to plasmin by a plasminogen activator produced by transformed cells. Our procedure, therefore, measures proteolytic activities other than those reported by previous investigators. Maintenance of some of the transformed phenotypes of Rous sarcoma virus transformed chick embryo fibroblasts such as morpholigical change and increased rate of glucose uptake apparently does not depend on the presence of plasminogen in the culture medium. Images PMID:165484

  7. Transition-Metal-Free CO-Releasing BODIPY Derivatives Activatable by Visible to NIR Light as Promising Bioactive Molecules.

    PubMed

    Palao, Eduardo; Slanina, Tomáš; Muchová, Lucie; Šolomek, Tomáš; Vítek, Libor; Klán, Petr

    2016-01-13

    Carbon monoxide-releasing molecules (CORMs) are chemical agents used to administer CO as an endogenous, biologically active molecule. A precise spatial and temporal control over the CO release is the major requirement for their applications. Here, we report the synthesis and properties of a new generation of transition-metal-free carbon monoxide-releasing molecules based on BODIPY chromophores (COR-BDPs) activatable by visible-to-NIR (up to 730 nm) light. We demonstrate their performance for both in vitro and in vivo experimental settings, and we propose the mechanism of the CO release based on steady-state and transient spectroscopy experiments and quantum chemical calculations. PMID:26697725

  8. Design and synthesis of phospholipase C and A2-activatable near-infrared fluorescent smart probes.

    PubMed

    Popov, Anatoliy V; Mawn, Theresa M; Kim, Soungkyoo; Zheng, Gang; Delikatny, E James

    2010-10-20

    The primary focus of this work was to develop activatable probes suitable for in vivo detection of phospholipase activity. Phospholipases (PLs) are ubiquitous enzymes that perform a number of critical regulatory functions. They catalyze phospholipid breakdown and are categorized as A(1), A(2) (PLA(2)), C (PLC), and D (PLD) based on their site of action. Here, we report the design, synthesis, and characterization of self-quenching reporter probes that release fluorescent moieties upon cleavage with PLA(2) or PLC. A series of phospholipids were synthesized bearing the NIR fluorophore pyropheophorbide a (Pyro) at the sn-2 position. Fluorescence quenching was achieved by attachment of either a positively charged black hole quencher-3 (BHQ-3) to the phospholipid headgroup or another neutral Pyro moiety at the sn-1 position. The specificity to different phospholipases was modulated by insertion of spacers (C(6), C(12)) between Pyro and the lipid backbone. The specificity of the quenched fluorescent phospholipids was assayed on a plate reader against a number of phospholipases and compared with two commercial probes bearing the visible fluorophore BODIPY. While PyroC(6)-PyroC(6)-PtdCho revealed significant background fluorescence, and a 10% fluorescence increase under the action of PLA(2), Pyro-PtdEtn-BHQ demonstrated high selective sensitivity to PLC, particularly to the PC-PLC isoform, and its sensitivity to PLA(2) was negligible due to steric hindrance at the sn-2 position. In contrast, the C(12)-spacered PyroC(12)-PtdEtn-BHQ demonstrated a remarkable selectivity for PLA(2) and the best relative PLA(2)/PLC sensitivity, significantly outperforming previously known probes. These results open an avenue for future in vivo experiments and for new probes to detect PL activity. PMID:20882956

  9. [Significance of urokinase and its inhibitors in the invasiveness and metastasing of malignant tumors].

    PubMed

    Halámková, J; Kiss, I; Tomášek, J; Pavlovský, Z; Tuček, S; Penka, M

    2012-02-01

    Fibrinolysis is process, which leads to the degradation of fibrin to fibrin monomers. Fibrinolysis helps to regulate hemostasis and prevents the creation of inappropriately large thrombus, which could reduce blood flow to the bloodstream. The main enzyme involved in fibrinolysis is plasmin. Tissue plasminogen activator (tPA) and urokinase (uPA) are agents converting plasminogen into active plasmin, together with urokinase receptor (uPAR) and urokinase inhibitors (PAI 1, PAI 2, PAI 3 and protease nexin) form plasminogen activator system (PAS) which is among others also part of the metastatic cascade and significantly contributes to invasive growth and angiogenesis of malignant tumours. In contrast to tPA that is fundamental in fibrinolysis, uPA plays an essential role in tissue degradation as part of physiological and pathological processes. uPAR is a GPI (glycosylphosphatidylinositol)-anchored protein. The binding of uPA to uPAR results in activation of protein tyrosine kinase, protein kinase C and MAP kinase. At the same time, direct signalling pathway via Jak/STAT cascade utilising signalling transduction of Scr-like protein tyrosine kinase have also been described. uPAR expression is regulated by many growth factors, e.g. EGF, FGF-2 and HGF. It seems that individual PAS factors are involved in the process of rendering malignant tumors invasive. To what degree this influence is essential to specific malignancies, should be answered by further research. In the article the authors present a summary of findings about the interaction of fibrinolysis and tumor process, especially on the effects of urokinase and other activators and their inhibitors in metastasis of malignant tumors. The text contains information on the factors theirs introduction into practice is still the subject of numerous discussions, but in the future, individual PAS factors could play an important role in planning treatment strategies and also could become targets of targeted therapy. PMID

  10. Fibrinolysis and Proliferative Endarteritis: Two Related Processes in Chronic Infections? The Model of the Blood-Borne Pathogen Dirofilaria immitis

    PubMed Central

    González-Miguel, Javier; Morchón, Rodrigo; Siles-Lucas, Mar; Simón, Fernando

    2015-01-01

    The interaction between blood-borne pathogens and fibrinolysis is one of the most important mechanisms that mediate invasion and the establishment of infectious agents in their hosts. However, overproduction of plasmin (final product of the route) has been related in other contexts to proliferation and migration of the arterial wall cells and degradation of the extracellular matrix. We have recently identified fibrinolysis-activating antigens from Dirofilaria immitis, a blood-borne parasite whose key pathological event (proliferative endarteritis) is produced by similar mechanisms to those indicated above. The objective of this work is to study how two of this antigens [actin (ACT) and fructose-bisphosphate aldolase (FBAL)] highly conserved in pathogens, activate fibrinolysis and to establish a relationship between this activation and the development of proliferative endarteritis during cardiopulmonary dirofilariasis. We demonstrate that both proteins bind plasminogen, enhance plasmin generation, stimulate the expression of the fibrinolytic activators tPA and uPA in endothelial cell cultures and are located on the surface of the worm in contact with the host’s blood. ELISA, western blot and immunofluorescence techniques were employed for this purpose. Additionally, the implication of lysine residues in this interaction was analyzed by bioinformatics. The involvement of plasmin generated by the ACT/FBAL and plasminogen binding in cell proliferation and migration, and degradation of the extracellular matrix were shown in an “in vitro” model of endothelial and smooth muscle cells in culture. The obtained results indicate that ACT and FBAL from D. immitis activate fibrinolysis, which could be used by the parasite like a survival mechanism to avoid the clot formation. However, long-term overproduction of plasmin can trigger pathological events similar to those described in the emergence of proliferative endarteritis. Due to the high degree of evolutionary

  11. Ticagrelor versus high dose clopidogrel in ST-segment elevation myocardial infarction patients with high platelet reactivity post fibrinolysis.

    PubMed

    Alexopoulos, Dimitrios; Perperis, Angelos; Koniari, Ioanna; Karvounis, Haralambos; Patsilinakos, Sotirios; Ziakas, Antonios; Barampoutis, Nikolaos; Panagiotidis, Theofilos; Akinosoglou, Karolina; Hahalis, George; Xanthopoulou, Ioanna

    2015-10-01

    Limited data are available on high platelet reactivity (HPR) rate early post fibrinolysis, while no effective way to overcome it has been proposed. In this context, we aimed to compare ticagrelor versus high dose clopidogrel in patients with ST-segment elevation myocardial infarction (STEMI) who exhibit HPR post fibrinolysis. In a prospective, randomized, parallel design, 3-center study, 56 STEMI patients, out of 83 (67.5 %) screened, who presented with HPR (PRU ≥ 208 by VerifyNow) 3-48 h post fibrinolysis and prior to coronary angiography were allocated to ticagrelor 180 mg loading dose (LD)/90 mg bid maintenance dose (MD) or clopidogrel 600 mg LD/150 mg MD. Platelet reactivity was assessed at randomization (Hour 0), at Hour 2, Hour 24 and pre-discharge. The primary endpoint of platelet reactivity (in PRU) at Hour 2 was significantly lower for ticagrelor compared to clopidogrel with a least square mean difference (95 % confidence interval) of -141.7 (-173.4 to -109.9), p < 0.001. HPR rates at Hour 2 and 24 were significantly lower for ticagrelor versus clopidogrel (14.3 vs. 82.1 %, p < 0.001 and 0 vs. 25.0 %, p = 0.01 respectively), though not significantly different pre-discharge. In-hospital Bleeding Academic Research Consortium type ≥2 bleeding occurred in 1 and 2 clopidogrel and ticagrelor-treated patients, respectively. In STEMI patients, post fibrinolysis HPR is common. Ticagrelor treats HPR more effectively compared to high dose clopidogrel therapy. Although antiplatelet regimens tested in this study were well tolerated, this finding should be considered only exploratory. PMID:25680893

  12. XTEN as Biological Alternative to PEGylation Allows Complete Expression of a Protease-Activatable Killin-Based Cytostatic

    PubMed Central

    Haeckel, Akvile; Appler, Franziska; Ariza de Schellenberger, Angela; Schellenberger, Eyk

    2016-01-01

    Increased effectiveness and reduced side effects are general goals in drug research, especially important in cancer therapy. The aim of this study was to design a long-circulating, activatable cytostatic drug that is completely producible in E. coli. Crucial for this goal was the novel unstructured polypeptide XTEN, which acts like polyethylene glycol (PEG) but has many important advantages. Most importantly, it can be produced in E. coli, is less immunogenic, and is biodegradable. We tested constructs containing a fragment of Killin as cytostatic/cytotoxic element, a cell-penetrating peptide, an MMP-2 cleavage site for specific activation, and XTEN for long blood circulation and deactivation of Killin. One of three sequence variants was efficiently expressed in E. coli. As typical for XTEN, it allowed efficient purification of the E. coli lysate by a heat step (10 min 75°C) and subsequent anion exchange chromatography using XTEN as purification tag. After 24 h XTEN-Killin reduced the number of viable cells of HT-1080 tumor cell line to 3.8 ±2.0% (p<0.001) compared to untreated controls. In contrast, liver derived non-tumor cells (BRL3A) did not show significant changes in viability. Our results demonstrate the feasibility of completely producing a complex protease-activatable, potentially long-circulating cytostatic/cytotoxic prodrug in E. coli—a concept that could lead to efficient production of highly multifunctional drugs in the future. PMID:27295081

  13. Activatable albumin-photosensitizer nanoassemblies for triple-modal imaging and thermal-modulated photodynamic therapy of cancer.

    PubMed

    Hu, Dehong; Sheng, Zonghai; Gao, Guanhui; Siu, Fungming; Liu, Chengbo; Wan, Qian; Gong, Ping; Zheng, Hairong; Ma, Yifan; Cai, Lintao

    2016-07-01

    Photodynamic therapy (PDT) is a noninvasive and effective approach for cancer treatment. The main bottlenecks of clinical PDT are poor selectivity of photosensitizer and inadequate oxygen supply resulting in serious side effects and low therapeutic efficiency. Herein, a thermal-modulated reactive oxygen species (ROS) strategy using activatable human serum albumin-chlorin e6 nanoassemblies (HSA-Ce6 NAs) for promoting PDT against cancer is developed. Through intermolecular disulfide bond crosslinking and hydrophobic interaction, Ce6 photosensitizer is effectively loaded into the HSA NAs, and the obtained HSA-Ce6 NAs exhibit excellent reduction response, as well as enhanced tumor accumulation and retention. By the precision control of the overall body temperature instead of local tumor temperature increasing from 37 °C to 43 °C, the photosensitization reaction rate of HSA-Ce6 NAs increases 20%, and the oxygen saturation of tumor tissue raise 52%, significantly enhancing the generation of ROS for promoting PDT. Meanwhile, the intrinsic fluorescence and photoacoustic properties, and the chelating characteristic of porphyrin ring can endow the HSA-Ce6 NAs with fluorescence, photoacoustic and magnetic resonance triple-modal imaging functions. Upon irradiation of low-energy near-infrared laser, the tumors are completely suppressed without tumor recurrence and therapy-induced side effects. The robust thermal-modulated ROS strategy combined with albumin-based activatable nanophotosensitizer is highly potential for multi-modal imaging-guided PDT and clinical translation. PMID:27061266

  14. pH-Activatable MnO-Based Fluorescence and Magnetic Resonance Bimodal Nanoprobe for Cancer Imaging.

    PubMed

    Hsu, Benedict You Wei; Ng, Michael; Tan, Aaron; Connell, John; Roberts, Thomas; Lythgoe, Mark; Zhang, Yu; Wong, Siew Yee; Bhakoo, Kishore; Seifalian, Alexander M; Li, Xu; Wang, John

    2016-03-01

    Stimuli-responsive nanoprobes that combine both fluorescence and magnetic resonance imaging (MRI) are anticipated to be highly beneficial for tumor visualization with high imaging sensitivity. By employing an interfacial templating scheme, a pH-activatable fluorescence/MRI dual-modality imaging nanoprobe is successfully developed based on the coencapsulation of MnO nanoparticles and coumarin-545T inside a hybrid silica nanoshell. To promote cancer cell targeting with high-specificity, the nanoprobes are also conjugated with folic acid to establish a greater affinity for cancer cells that over-express folate receptors on their cell membrane. In the new nanosystem, MnO nanoparticles are shown to function as an efficient fluorescence quencher of coumarin-545T prior to cellular uptake. However, fluorescence recovery is achieved upon acidic dissolution of the MnO nanoparticles following receptor-mediated endocytosis into the low pH compartments of the cancer cells. Meanwhile, the Mn(2+) ions thus released are also shown to exert a strong T1 contrast enhancement in the cancer cells. Therefore, by demonstrating the dual-activatable MRI and fluorescence imaging in response to the low pH conditions, it is envisioned that these nanoprobes would have tremendous potential for emerging cancer-imaging modalities such as image-guided cancer therapy. PMID:26895111

  15. Self-Assembled Nanostructures Based on Activatable Red Fluorescent Dye for Site-Specific Protein Probing and Conformational Transition Detection.

    PubMed

    Yu, Yang; Huang, Yanyan; Hu, Fang; Jin, Yulong; Zhang, Guanxin; Zhang, Deqing; Zhao, Rui

    2016-06-21

    Smart and versatile nanostructures have demonstrated their effectiveness for biomolecule analysis and show great potential in digging insights into the structural/functional relationships. Herein, a nanoscale molecular self-assembly was constructed for probing the site-specific recognition and conformational changes of human serum albumin (HSA) with tunable size and emission. A tetraphenylethylene derivative TPE-red-COOH was used as the building block for tailoring fluorescence-silent nanoparticles. The highly specific and sensitive response to HSA was witnessed by the fast turn-on of the red fluorescence and simultaneous disassembly of the nanostructures, whereas various endogenous biomolecules cannot induce such response. The mechanism investigation indicates that the combination of multiple noncovalent interactions is the driving force for disassembling and trapping TPE-red-COOH into HSA. The resultant restriction of intramolecular rotation of TPE-red-COOH in the hydrophobic cavity of HSA induces the significant red emission. By using the fluorescence activatable nanosensor as the structural indicator, the stepwise conformational transitions of HSA during denaturing and the partial refolding of subdomain IIA of HSA were facilely visualized. Benefiting from its activatable signaling, sensitivity, and simplicity, such molecular assembly provides a kind of soft nanomaterial for site-specific biomolecule probing and conformational transition detection concerning their structure, function, and biomedical characteristics. PMID:27232658

  16. XTEN as Biological Alternative to PEGylation Allows Complete Expression of a Protease-Activatable Killin-Based Cytostatic.

    PubMed

    Haeckel, Akvile; Appler, Franziska; Ariza de Schellenberger, Angela; Schellenberger, Eyk

    2016-01-01

    Increased effectiveness and reduced side effects are general goals in drug research, especially important in cancer therapy. The aim of this study was to design a long-circulating, activatable cytostatic drug that is completely producible in E. coli. Crucial for this goal was the novel unstructured polypeptide XTEN, which acts like polyethylene glycol (PEG) but has many important advantages. Most importantly, it can be produced in E. coli, is less immunogenic, and is biodegradable. We tested constructs containing a fragment of Killin as cytostatic/cytotoxic element, a cell-penetrating peptide, an MMP-2 cleavage site for specific activation, and XTEN for long blood circulation and deactivation of Killin. One of three sequence variants was efficiently expressed in E. coli. As typical for XTEN, it allowed efficient purification of the E. coli lysate by a heat step (10 min 75°C) and subsequent anion exchange chromatography using XTEN as purification tag. After 24 h XTEN-Killin reduced the number of viable cells of HT-1080 tumor cell line to 3.8 ±2.0% (p<0.001) compared to untreated controls. In contrast, liver derived non-tumor cells (BRL3A) did not show significant changes in viability. Our results demonstrate the feasibility of completely producing a complex protease-activatable, potentially long-circulating cytostatic/cytotoxic prodrug in E. coli-a concept that could lead to efficient production of highly multifunctional drugs in the future. PMID:27295081

  17. Microbial light-activatable proton pumps as neuronal inhibitors to functionally dissect neuronal networks in C. elegans.

    PubMed

    Husson, Steven J; Liewald, Jana F; Schultheis, Christian; Stirman, Jeffrey N; Lu, Hang; Gottschalk, Alexander

    2012-01-01

    Essentially any behavior in simple and complex animals depends on neuronal network function. Currently, the best-defined system to study neuronal circuits is the nematode Caenorhabditis elegans, as the connectivity of its 302 neurons is exactly known. Individual neurons can be activated by photostimulation of Channelrhodopsin-2 (ChR2) using blue light, allowing to directly probe the importance of a particular neuron for the respective behavioral output of the network under study. In analogy, other excitable cells can be inhibited by expressing Halorhodopsin from Natronomonas pharaonis (NpHR) and subsequent illumination with yellow light. However, inhibiting C. elegans neurons using NpHR is difficult. Recently, proton pumps from various sources were established as valuable alternative hyperpolarizers. Here we show that archaerhodopsin-3 (Arch) from Halorubrum sodomense and a proton pump from the fungus Leptosphaeria maculans (Mac) can be utilized to effectively inhibit excitable cells in C. elegans. Arch is the most powerful hyperpolarizer when illuminated with yellow or green light while the action spectrum of Mac is more blue-shifted, as analyzed by light-evoked behaviors and electrophysiology. This allows these tools to be combined in various ways with ChR2 to analyze different subsets of neurons within a circuit. We exemplify this by means of the polymodal aversive sensory ASH neurons, and the downstream command interneurons to which ASH neurons signal to trigger a reversal followed by a directional turn. Photostimulating ASH and subsequently inhibiting command interneurons using two-color illumination of different body segments, allows investigating temporal aspects of signaling downstream of ASH. PMID:22815873

  18. Plasma pentraxin-3 and coagulation and fibrinolysis variables during acute Puumala hantavirus infection and associated thrombocytopenia.

    PubMed

    Laine, Outi K; Koskela, Sirpa M; Outinen, Tuula K; Joutsi-Korhonen, Lotta; Huhtala, Heini; Vaheri, Antti; Hurme, Mikko A; Jylhävä, Juulia; Mäkelä, Satu M; Mustonen, Jukka T

    2014-09-01

    Thrombocytopenia and altered coagulation characterize all hantavirus infections. To further assess the newly discovered predictive biomarkers of disease severity during acute Puumala virus (PUUV) infection, we studied the associations between them and the variables reflecting coagulation, fibrinolysis and endothelial activation. Nineteen hospital-treated patients with serologically confirmed acute PUUV infection were included. Acutely, plasma levels of pentraxin-3 (PTX3), cell-free DNA (cf-DNA), complement components SC5b-9 and C3 and interleukin-6 (IL-6) were recorded as well as platelet ligands and markers of coagulation and fibrinolysis. High values of plasma PTX3 associated with thrombin formation (prothrombin fragments F1+2; r = 0.46, P = 0.05), consumption of platelet ligand fibrinogen (r = -0.70, P < 0.001) and natural anticoagulants antithrombin (AT) (r = -0.74, P < 0.001), protein C (r = -0.77, P < 0.001) and protein S free antigen (r = -0.81, P < 0.001) and a decreased endothelial marker ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 domain 13) (r = -0.48, P = 0.04). Plasma level of AT associated with C3 (r = 0.76, P < 0.001), IL-6 (r = -0.56, P = 0.01) and cf-DNA (r = -0.47, P = 0.04). High cf-DNA coincided with increased prothrombin fragments F1+2 (r = 0.47, P = 0.04). Low C3 levels reflecting the activation of complement system through the alternative route predicted loss of all natural anticoagulants (for protein C r = 0.53, P = 0.03 and for protein S free antigen r = 0.64, P = 0.004). Variables depicting altered coagulation follow the new predictive biomarkers of disease severity, especially PTX3, in acute PUUV infection. The findings are consistent with the previous observations of these biomarkers also being predictive for low platelet count and underline the cross-talk of inflammation and coagulation systems in acute PUUV infection. PMID:24751477

  19. Ramipril and Losartan Exert a Similar Long-Term Effect upon Markers of Heart Failure, Endogenous Fibrinolysis, and Platelet Aggregation in Survivors of ST-Elevation Myocardial Infarction: A Single Centre Randomized Trial

    PubMed Central

    Marinšek, Martin; Sinkovič, Andreja

    2016-01-01

    Introduction. Blocking the renin-angiotensin-aldosterone system in ST-elevation myocardial infarction (STEMI) patients prevents heart failure and recurrent thrombosis. Our aim was to compare the effects of ramipril and losartan upon the markers of heart failure, endogenous fibrinolysis, and platelet aggregation in STEMI patients over the long term. Methods. After primary percutaneous coronary intervention (PPCI), 28 STEMI patients were randomly assigned ramipril and 27 losartan, receiving therapy for six months with dual antiplatelet therapy (DAPT). We measured N-terminal proBNP (NT-proBNP), ejection fraction (EF), plasminogen-activator-inhibitor type 1 (PAI-1), and platelet aggregation by closure times (CT) at the baseline and after six months. Results. Baseline NT-proBNP ≥ 200 pmol/mL was observed in 48.1% of the patients, EF < 55% in 49.1%, and PAI-1 ≥ 3.5 U/mL in 32.7%. Six-month treatment with ramipril or losartan resulted in a similar effect upon PAI-1, NT-proBNP, EF, and CT levels in survivors of STEMI, but in comparison to control group, receiving DAPT alone, ramipril or losartan treatment with DAPT significantly increased mean CT (226.7 ± 80.3 sec versus 158.1 ± 80.3 sec, p < 0.05). Conclusions. Ramipril and losartan exert a similar effect upon markers of heart failure and endogenous fibrinolysis, and, with DAPT, a more efficient antiplatelet effect in long term than DAPT alone. PMID:27064499

  20. Fibrinolysis is essential for fracture repair and prevention of heterotopic ossification

    PubMed Central

    Yuasa, Masato; Mignemi, Nicholas A.; Nyman, Jeffry S.; Duvall, Craig L.; Schwartz, Herbert S.; Okawa, Atsushi; Yoshii, Toshitaka; Bhattacharjee, Gourab; Zhao, Chenguang; Bible, Jesse E.; Obremskey, William T.; Flick, Matthew J.; Degen, Jay L.; Barnett, Joey V.; Cates, Justin M.M.; Schoenecker, Jonathan G.

    2015-01-01

    Bone formation during fracture repair inevitably initiates within or around extravascular deposits of a fibrin-rich matrix. In addition to a central role in hemostasis, fibrin is thought to enhance bone repair by supporting inflammatory and mesenchymal progenitor egress into the zone of injury. However, given that a failure of efficient fibrin clearance can impede normal wound repair, the precise contribution of fibrin to bone fracture repair, whether supportive or detrimental, is unknown. Here, we employed mice with genetically and pharmacologically imposed deficits in the fibrin precursor fibrinogen and fibrin-degrading plasminogen to explore the hypothesis that fibrin is vital to the initiation of fracture repair, but impaired fibrin clearance results in derangements in bone fracture repair. In contrast to our hypothesis, fibrin was entirely dispensable for long-bone fracture repair, as healing fractures in fibrinogen-deficient mice were indistinguishable from those in control animals. However, failure to clear fibrin from the fracture site in plasminogen-deficient mice severely impaired fracture vascularization, precluded bone union, and resulted in robust heterotopic ossification. Pharmacological fibrinogen depletion in plasminogen-deficient animals restored a normal pattern of fracture repair and substantially limited heterotopic ossification. Fibrin is therefore not essential for fracture repair, but inefficient fibrinolysis decreases endochondral angiogenesis and ossification, thereby inhibiting fracture repair. PMID:26214526

  1. Polypyrrole-based nanotheranostics for activatable fluorescence imaging and chemo/photothermal dual therapy of triple-negative breast cancer

    NASA Astrophysics Data System (ADS)

    Park, Dongjin; Ahn, Kyung-Ohk; Jeong, Kyung-Chae; Choi, Yongdoo

    2016-05-01

    Here, we fabricated polypyrrole nanoparticles (PPys) (termed HA10-PPy, HA20-PPy, and HA40-PPy) doped with different average molecular weight hyaluronic acids (HAs) (10, 20, and 40 kDa, respectively), and evaluated the effect of molecular weight of doped HA on photothermal induction, fluorescence quenching, and drug loading efficiencies. Doxorubicin-loaded HA-doped PPys (DOX@HA-PPys) could be used for imaging and therapy of triple-negative breast cancer (TNBC). Fluorescence turn-on, stimuli-responsive drug release, and photo-induced heating of DOX@HA-PPys enabled not only activatable fluorescence imaging but also subsequent chemo/photothermal dual therapy for TNBC. In particular, we illustrated the potential usefulness of the photothermal effect of the nanoparticles for overcoming chemoresistance in TNBC.

  2. Polypyrrole-based nanotheranostics for activatable fluorescence imaging and chemo/photothermal dual therapy of triple-negative breast cancer.

    PubMed

    Park, Dongjin; Ahn, Kyung-Ohk; Jeong, Kyung-Chae; Choi, Yongdoo

    2016-05-01

    Here, we fabricated polypyrrole nanoparticles (PPys) (termed HA10-PPy, HA20-PPy, and HA40-PPy) doped with different average molecular weight hyaluronic acids (HAs) (10, 20, and 40 kDa, respectively), and evaluated the effect of molecular weight of doped HA on photothermal induction, fluorescence quenching, and drug loading efficiencies. Doxorubicin-loaded HA-doped PPys (DOX@HA-PPys) could be used for imaging and therapy of triple-negative breast cancer (TNBC). Fluorescence turn-on, stimuli-responsive drug release, and photo-induced heating of DOX@HA-PPys enabled not only activatable fluorescence imaging but also subsequent chemo/photothermal dual therapy for TNBC. In particular, we illustrated the potential usefulness of the photothermal effect of the nanoparticles for overcoming chemoresistance in TNBC. PMID:27004751

  3. Real-time In Vivo Molecular Detection of Primary Tumors and Metastases with Ratiometric Activatable Cell-Penetrating Peptides

    PubMed Central

    Savariar, Elamprakash N.; Felsen, Csilla N.; Nashi, Nadia; Jiang, Tao; Ellies, Lesley G.; Steinbach, Paul; Tsien, Roger Y.; Nguyen, Quyen T.

    2013-01-01

    Management of metastatic disease is integral to cancer treatment. Evaluation of metastases often requires surgical removal of all anatomically susceptible lymph nodes for ex vivo pathologic examination. We report a family of novel ratiometric activatable cell-penetrating peptides, which contain Cy5 as far red fluorescent donor and Cy7 as near-infrared fluorescent acceptor. Cy5 is quenched in favor of Cy7 reemission until the intervening linker is cut by tumor-associated matrix metalloproteinases-2 and 9 (MMP2,9) or elastases. Such cleavage increases the Cy5:Cy7 emission ratio 40-fold and triggers tissue retention of the Cy5-containing fragment. This ratiometric increase provides an accelerated and quantifiable metric to identify primary tumors and metastases to liver and lymph nodes with increased sensitivity and specificity. This technique represents a significant advance over existing nonratiometric protease sensors and sentinel lymph node detection methods, which give no information about cancer invasion. PMID:23188503

  4. Effect of reference spectra in spectral fitting to discriminate enzyme-activatable photoacoustic probe from intrinsic optical absorbers

    NASA Astrophysics Data System (ADS)

    Hirasawa, Takeshi; Okawa, Shinpei; Iwatate, Ryu J.; Kamiya, Mako; Urano, Yasuteru; Ishihara, Miya

    2016-03-01

    Multispectral photoacoustic (MS-PA) imaging has been researched to image molecular probes in the presence of strong background signals produced from intrinsic optical absorbers. Spectral fitting method (SFM) discriminates probe signals from background signals by fitting the PA spectra that are calculated from MS-PA images to reference spectra of the probe and background, respectively. Because hemoglobin is a dominant optical absorber in visible to near-infrared wavelength range, absorption spectra of hemoglobin have been widely used as reference background spectra. However, the spectra of background signals produced from heterogeneous biological tissue differ from the reference background spectra due to presence of other intrinsic optical absorbers and effect of optical scattering. Due to the difference, the background signals partly remain in the probe images. To image the probe injected in subcutaneous tumors of mice clearly, we added the melanosome absorption spectrum to the reference background spectra because skin contains nonnegligible concentration of melanosome and the spectrum is very similar to the scattering spectrum of biological tissue. The probe injected in the subcutaneous tumor of mice was an enzyme-activatable probe which show their original colors only in the presence of γ-glutamyltranspeptidase, an enzyme associated with cancer. The probes have been successfully used for rapid fluorescence imaging of cancer. As a result of MS-PA imaging, by considering the melanosome absorption spectrum, the background signals were successfully suppressed and then clearer probe image was obtained. Our MS-PA imaging method afforded successful imaging of tumors in mice injected with activatable PA probes.

  5. Near-Infrared Light-Activatable Microneedle System for Treating Superficial Tumors by Combination of Chemotherapy and Photothermal Therapy.

    PubMed

    Chen, Mei-Chin; Lin, Zhi-Wei; Ling, Ming-Hung

    2016-01-26

    Because of the aggressive and recurrent nature of cancers, repeated and multimodal treatments are often necessary. Traditional cancer therapies have a risk of serious toxicity and side effects. Hence, it is crucial to develop an alternative treatment modality that is minimally invasive, effectively treats cancers with low toxicity, and can be repeated as required. We developed a light-activatable microneedle (MN) system that can repeatedly and simultaneously provide photothermal therapy and chemotherapy to superficial tumors and exert synergistic anticancer effects. This system consists of embeddable polycaprolactone MNs containing a photosensitive nanomaterial (lanthanum hexaboride) and an anticancer drug (doxorubicin; DOX), and a dissolvable poly(vinyl alcohol)/polyvinylpyrrolidone supporting array patch. Because of this supporting array, the MNs can be completely inserted into the skin and embedded within the target tissue for locoregional cancer treatment. When exposed to near-infrared light, the embedded MN array uniformly heats the target tissue to induce a large thermal ablation area and then melts at 50 °C to release DOX in a broad area, thus destroying tumors. This light-activated heating and releasing behavior can be precisely controlled and switched on and off on demand for several cycles. We demonstrated that the MN-mediated synergistic therapy completely eradicated 4T1 tumors within 1 week after a single application of the MN and three cycles of laser treatment. No tumor recurrence and no significant body weight loss of mice were observed. Thus, the developed light-activatable MN with a unique embeddable feature offers an effective, user-friendly, and low-toxicity option for patients requiring long-term and multiple cancer treatments. PMID:26592739

  6. Photoacoustic Imaging: Semiconducting Oligomer Nanoparticles as an Activatable Photoacoustic Probe with Amplified Brightness for In Vivo Imaging of pH (Adv. Mater. 19/2016).

    PubMed

    Miao, Qingqing; Lyu, Yan; Ding, Dan; Pu, Kanyi

    2016-05-01

    Despite the great potential of photoacoustic imaging in the life sciences, the development of smart activatable photoacoustic probes remains elusive. On page 3662, K. Pu and co-workers report a facile nanoengineering approach based on semiconducting oligomer nano-particles to develop ratiometric photoacoustic probes with amplified brightness and enhanced sensing capability for accurate photoacoustic mapping of pH in the tumors of living mice. PMID:27167028

  7. [Comparison of platelet activity, fibrinolysis and environmental factors in 50 Africans and 50 Europeans. Role of fish consumption].

    PubMed

    Bertrand, E; Cloitre, B; Ticolat, R; Darracq, R; Rain, S F

    1987-01-01

    The authors have studied 50 Ivorians and 50 Europeans people, all living in Abidjan for at least 10 years. Platelet aggregability with increasing ADP concentration (0.6, 1.2, 2.4 mumoles/l), collagen (0.4 mg/l), or ristocetin (1 g/l) was examined. Fibrinolysis and the euglobulin test were also studied before and after anoxia. Other blood parameters measured were: hematocrit, hemoglobin level, platelet count, bleeding time, Howell coagulation test, cephalin tests, prothrombin activity ratio, fibrinogen level. Metabolic tests included: glycemia, cholesterolemia, triglyceridemia, uricemia, A1 and B apoproteins, protidemia, gamma globulinemia. Environmental factors such as physical activity, alcohol and smoking habits, fish consumption, chloroquine prophylaxis were evaluated. The most evident result was lower platelet aggregability in Ivorian people as compared to Europeans. A more precocious and important fibrinolysis activity, either spontaneous or after anoxia was noted in the Ivorian group. Lower platelet number, fibrinogen level, and prothrombin activity were present in the Ivorian group as compared to the European people. The authors eliminated the influence of age, and considered environmental factors as predominant in the genesis of such difference, i.e., hypocholesterolemia, lower smoking and drinking levels. They emphasized the higher fish consumption in Ivorian people. PMID:2827101

  8. Massive Pulmonary Embolism: Treatment with Thrombus Fragmentation and Local Fibrinolysis with Recombinant Human-Tissue Plasminogen Activator

    SciTech Connect

    Stock, Klaus Wilhelm; Jacob, Augustinus Ludwig; Schnabel, Karl Jakob; Bongartz, Georg; Steinbrich, Wolfgang

    1997-09-15

    Purpose: To report the results of thrombus fragmentation in combination with local fibrinolysis using recombinant human-tissue plasminogen activator (rtPA) in patients with massive pulmonary embolism. Methods: Five patients with massive pulmonary embolism were treated with thrombus fragmentation followed by intrapulmonary injection of rtPA. Clot fragmentation was performed with a guidewire, angiographic catheter, and balloon catheter. Three patients had undergone recent surgery; one of them received a reduced dosage of rtPA. Results: All patients survived and showed clinical improvement with a resultant significant (p < 0.05) decrease in the pulmonary blood pressure (mean systolic pulmonary blood pressure before treatment, 49 mmHg; 4 hr after treatment, 28 mmHg). Angiographic follow-up in three patients revealed a decrease in thrombus material and an increase in pulmonary perfusion. Two patients developed retroperitoneal hematomas requiring transfusion. Conclusion: Clot fragmentation and local fibrinolysis with rtPA was an effective therapy for massive pulmonary embolism. Bleeding at the puncture site was a frequent complication.

  9. Imaging Dendrimer-Grafted Graphene Oxide Mediated Anti-miR-21 Delivery With an Activatable Luciferase Reporter.

    PubMed

    Wang, Fu; Zhang, Beilei; Zhou, Lin; Shi, Yaru; Li, Zhiqiang; Xia, Yuqiong; Tian, Jie

    2016-04-13

    MicroRNAs (miRNAs) are a class of post-transcriptional gene regulators involved in various physiological processes including carcinogenesis, and they have emerged as potential targets for tumor theranostics. However, the employment of antisense oligonucleotides, termed anti-miRs, for antagonizing miRNA functions in vivo has largely been impeded by a lack of effective delivery carriers. Here, we describe the development of polyamidoamine (PAMAM) dendrimer and polyethylene glycol (PEG)-functionalized nanographene oxide (NGO) conjugate (NGO-PEG-dendrimer) for the efficient delivery of anti-miR-21 into non-small-cell lung cancer cells. To monitor the delivery of anti-miR-21 into cells and tumors, we also constructed an activatable luciferase reporter (Fluc-3xPS) containing three perfectly complementary sequences against miR-21 in the 3' untranslated region (UTR) of the reporter. Compared with bare dendrimer and Lipofectamine 2000 (Lipo2000), NGO-PEG-dendrimer showed considerably lower cytotoxicity and higher transfection efficiency. As demonstrated by in vitro bioluminescence imaging and Western blotting assays, NGO-PEG-dendrimer effectively delivered anti-miR-21 into the cytoplasm and resulted in the upregulation of luciferase intensity and PTEN target protein expression in a dose-dependent manner. Moreover, transfection with anti-miR-21 by NGO-PEG-dendrimer led to stronger inhibition of cell migration and invasion than did bare dendrimer or Lipo2000 transfection. The intravenous delivery of anti-miR-21 via NGO-PEG-dendrimer induced a significant increase in the bioluminescence signal within the Fluc-3xPS reporter-transplanted tumor areas. These results suggest that NGO-PEG-dendrimer could be an efficient and a potential nanocarrier for delivering RNA oligonucleotides. In addition, the strategy of combining NGO-PEG-dendrimer with an activatable luciferase reporter allows the image-guided monitoring of the delivery process, which can provide insights into the RNA

  10. A Spider-Derived Kunitz-Type Serine Protease Inhibitor That Acts as a Plasmin Inhibitor and an Elastase Inhibitor

    PubMed Central

    Wan, Hu; Lee, Kwang Sik; Kim, Bo Yeon; Zou, Feng Ming; Yoon, Hyung Joo; Je, Yeon Ho; Li, Jianhong; Jin, Byung Rae

    2013-01-01

    Kunitz-type serine protease inhibitors are involved in various physiological processes, such as ion channel blocking, blood coagulation, fibrinolysis, and inflammation. While spider-derived Kunitz-type proteins show activity in trypsin or chymotrypsin inhibition and K+ channel blocking, no additional role for these proteins has been elucidated. In this study, we identified the first spider (Araneus ventricosus) Kunitz-type serine protease inhibitor (AvKTI) that acts as a plasmin inhibitor and an elastase inhibitor. AvKTI possesses a Kunitz domain consisting of a 57-amino-acid mature peptide that displays features consistent with Kunitz-type inhibitors, including six conserved cysteine residues and a P1 lysine residue. Recombinant AvKTI, expressed in baculovirus-infected insect cells, showed a dual inhibitory activity against trypsin (Ki 7.34 nM) and chymotrypsin (Ki 37.75 nM), defining a role for AvKTI as a spider-derived Kunitz-type serine protease inhibitor. Additionally, AvKTI showed no detectable inhibitory effects on factor Xa, thrombin, or tissue plasminogen activator; however, AvKTI inhibited plasmin (Ki 4.89 nM) and neutrophil elastase (Ki 169.07 nM), indicating that it acts as an antifibrinolytic factor and an antielastolytic factor. These findings constitute molecular evidence that AvKTI acts as a plasmin inhibitor and an elastase inhibitor and also provide a novel view of the functions of a spider-derived Kunitz-type serine protease inhibitor. PMID:23308198

  11. Surgical molecular navigation with a Ratiometric Activatable Cell Penetrating Peptide improves intraoperative identification and resection of small salivary gland cancers

    PubMed Central

    Hussain, Timon; Savariar, Elamprakash N.; Diaz-Perez, Julio A.; Messer, Karen; Pu, Minya; Tsien, Roger Y.; Nguyen, Quyen T.

    2015-01-01

    Background We evaluated the use of intraoperative fluorescence guidance by enzymatically cleavable ratiometric activatable cell-penetrating peptide (RACPPPLGC(Me)AG) containing Cy5 as a fluorescent donor and Cy7 as a fluorescent acceptor for salivary gland cancer surgery in a mouse model. Methods Surgical resection of small parotid gland cancers in mice was performed with fluorescence guidance or white light (WL) imaging alone. Tumor identification accuracy, operating time and tumor free survival were compared. Results RACPP guidance aided tumor detection (positive histology in 90% (27/30) vs. 48% (15/31) for WL, p<0.001). A ~25% ratiometric signal increase as the threshold to distinguish between tumor and adjacent tissue, yielded >90% detection sensitivity and specificity. Operating time was reduced by 54% (p<0.001), tumor free survival was increased with RACPP guidance (p=0.025). Conclusions RACPP provides real-time intraoperative guidance leading to improved survival. Ratiometric signal thresholds can be set according to desired detection accuracy levels for future RACPP applications. PMID:25521629

  12. The construction and in vitro testing of photo-activatable cancer targeting folated anti-CD3 conjugates

    SciTech Connect

    Thompson, Stephen Dessi, John; Self, Colin H.

    2008-02-08

    The construction and in vitro testing of a photo-activatable anti-tumour immuno-regulatory antibody is described. In this 'cloaked' folated anti-CD3 antibody conjugate, the folate portion of the conjugate is free to bind to folate receptor expressing cancer cells, whilst the anti-CD3 activity is effectively rendered inert by a coating of photo-labile 2-nitrobenzyl groups. On irradiation with UV-A light the activity of the anti-CD3 antibody is restored, not only when it is required, but more importantly, only where it is required. The conjugate can then attract killer T-cells to the surface of the tumour cells and kill them. Unirradiated normal tissues, to which the conjugate has been targeted by specific and non-specific binding, remain unharmed. We believe that these 'photo-switchable' conjugates could be used to markedly improve the targeting of the immune response to folate receptor (FR) expressing ovarian and breast cancers whilst minimising the side effects in the rest of the body.

  13. Design of a simultaneous target and location-activatable fluorescent probe for visualizing hydrogen sulfide in lysosomes.

    PubMed

    Yang, Sheng; Qi, Yue; Liu, Changhui; Wang, Yijun; Zhao, Yirong; Wang, Lili; Li, Jishan; Tan, Weihong; Yang, Ronghua

    2014-08-01

    Molecular tools capable of providing information on a target analyte in an organelle of interest are especially appreciated. Traditionally, organelle-targetable probes are designed by incorporating an organelle-specific guiding unit to target the probe molecules into the organelle. The imperfect targeting function of the guiding unit and nonspecific distribution of the analyte in cytosol and each organelle would lead to low spatiotemporal resolution and limited sensitivity. To solve this problem, we report herein a new approach for detection of a target analyte in a specific organelle by engineering a target and location dual-controlled molecular switch. For this proof-of-concept study, fluorescent detection of H2S in lysosomes was performed with a simultaneous H2S and proton-activatable probe based on the acidic environment of lysosomes. The new synthesized fluorescent sensor, "SulpHensor", which contains a spirolactam moiety to bind hydrogen protons and an azide group to react with H2S, displays highly sensitive and selective fluorescence response to H2S under lysosomal pH environment but is out of operation in neutral cytosol and other organelles. Fluorescence imaging shows that SulpHensor is membrane-permeable and suitable for visualization of both the exogenous and endogenous H2S in lysosomes of living cells. The good performance of our proposed approach for H2S sensing demonstrates that this strategy might open up new opportunities for the development of efficient subcellular molecular tools for bioanalytical and biomedical applications. PMID:24975419

  14. Activatable fluorescent cys-diabody conjugated with indocyanine green derivative: consideration of fluorescent catabolite kinetics on molecular imaging

    PubMed Central

    Sano, Kohei; Nakajima, Takahito; Ali, Towhid; Bartlett, Derek W.; Wu, Anna M.; Kim, Insook; Paik, Chang H.; Choyke, Peter L.

    2013-01-01

    Abstract. Antibody fragments including diabodies have more desirable pharmacokinetic characteristics than whole antibodies. An activatable optical imaging probe based on a cys-diabody targeting prostate-specific membrane antigen conjugated with the near-infrared fluorophore, indocyanine green (ICG), was designed such that it can only be activated when bound to the tumor, leading to high signal-to-background ratios. We employed short polyethylene glycol (PEG) linkers between the ICG and the reactive functional group (Sulfo-OSu group), resulting in covalent conjugation of ICG to the cys-diabody, which led to lower dissociation of ICG from cys-diabody early after injection, reducing hepatic uptake. However, unexpectedly, high and long-term fluorescence was observed in the kidneys, liver, and blood pool more than 1 h after injection of the cys-diabody PEG-ICG conjugate. A biodistribution study using I125-labeled cys-diabody-ICG showed immediate uptake in the kidneys followed by a rapid decrease, while gastric activity increased due to released radioiodine during rapid cys-diabody-ICG catabolism in the kidneys. To avoid this catabolic pathway, it would be preferable to use antibody fragments large enough not to be filtered through glomerulus or to conjugate the fragments with fluorescent dyes that are readily excreted into urine when cleaved from the cys-diabody to achieve high tumor-specific detection. PMID:23752742

  15. Increased fibrin formation and impaired fibrinolytic capacity in severe chronic kidney disease.

    PubMed

    Mörtberg, Josefin; Blombäck, Margareta; Wallén, Åkan; He, Shu; Jacobson, Stefan H; Spaak, Jonas

    2016-06-01

    Chronic kidney disease (CKD) is associated with a concurrent increased risk of thrombosis and bleeding. We aimed to investigate whether CKD is associated with increased fibrin formation, impaired fibrin degradation, or both. Twenty-one patients with CKD stage 4 (CKD 4), 15 haemodialysis patients, and 13 controls (C) without kidney disease were studied. We used a global assay to determine fibrin formation and degradation in plasma. Fibrin turbidity was measured over time to obtain a value of the coagulation activation profile (Cp) and the fibrinolysis activation profile (Fp), and the amount of fibrin formed, termed fibrin optical density sum (fibrin OD-sum). We used scanning electron microscopy (SEM) to visualize the fibrin network. Plasminogen activator inhibitor type-1 antigen, thrombin-activatable fibrinolysis inhibitor activity, fibrinogen, von Willebrand factor, antithrombin, albumin, and C-reactive protein were measured in plasma. Fibrin OD-sum was significantly elevated in haemodialysis patients [312 a.u.; 278-435 (median; interquartile range); P < 0.0013] and in CKD 4 (293 a.u.; 169-434; P = 0.0119) compared with controls (115 a.u.; 82-234). SEM showed a tight fibrin network in haemodialysis and CKD 4 patients. Fp was lower in the haemodialysis group than in controls (P = 0.030). Plasminogen activator inhibitor type-1 was lower in haemodialysis patients (P = 0.034). Thrombin-activatable fibrinolysis inhibitor activity, Cp, antithrombin, and C-reactive protein did not differ between groups. Fibrinogen was significantly elevated and albumin decreased in both haemodialysis and CKD 4 patients compared with controls. Von Willebrand factor was elevated in haemodialysis patients compared with controls (P = 0.010). The prothrombotic state in severe CKD is characterized by impaired fibrinolysis in association with increased fibrin formation despite normal levels of endogenous fibrinolysis inhibitors. PMID:26650459

  16. The impact of schistosomes and schistosomiasis on murine blood coagulation and fibrinolysis as determined by thromboelastography (TEG).

    PubMed

    Da'dara, Akram A; de Laforcade, Armelle M; Skelly, Patrick J

    2016-05-01

    Schistosomes are parasitic platyhelminths that currently infect over 200 million people and cause the chronic debilitating disease schistosomiasis. While these large intravascular parasites can disturb blood flow, surprisingly they do not appear to provoke thrombus formation around them in vivo. In order to determine if the worms can alter their local environment to impede coagulation, we incubated adult worms (50 pairs) in murine blood (500 µl) for 1 h at 37 °C and, using thromboelastography (TEG), we compared the coagulation profile of the blood with control blood that never contained worms. Substantial differences were apparent between the two profiles. Blood that had been exposed to schistosomes clotted more slowly and yielded relatively poor, though stable, thrombi; all TEG measures of blood coagulation (R, K, α-angle, MA, G and TMA) differed significantly between conditions. No fibrinolysis (as determined by LY30 and LY60 values) was detected in either case. The observed TEG profile suggests that the worms are acting as local anti-coagulants. Blood recovered from schistosome-infected mice, however, does not behave in this way. At an early time point post infection (4-weeks), the TEG profile of infected murine blood is essentially the same as that of control blood. However at a later time point (7-weeks) infected murine blood clots significantly faster than control blood but these clots also break down faster. The R, K, α-angle, and TMA measures of coagulation are all significantly different between the control versus infected mice as are the LY30 and LY60 values. This profile is indicative of a hypercoagulable state with fibrinolysis and is akin to that seen in human patients with advanced schistosomiasis. PMID:26573180

  17. Design and study of activatable ("OFF/ON") quantum dots (Qdots): ligand selection for Qdot surface modification for controlling Qdot fluorescence quenching and restoration

    NASA Astrophysics Data System (ADS)

    Teblum, Andrew; Basumallick, Srijita; Shah, Rikhav; Mitra, Rajendra N.; Banerjee, Subhash; Santra, Swadeshmukul

    2012-03-01

    We report design and synthesis of a series of activatable "OFF/ON" CdS:Mn/ZnS quantum dot (Qdot) based sensing probes. The Qdot "OFF" state represent the "quenched state" where the Qdot fluorescence is quenched by ligands attached to Qdot surface. Fluorescence quenching is likely due to ligand assisted electron transfer process. Qdot fluorescence is restored when the electron transfer process is stopped. Using this activatable Qdots, we have successfully demonstrated usefulness of these Qdot probes for reliable detection of toxic cadmium ions in solution, selective detection of glutathione and sensitive detection of intracellular cancer drug release event. In this paper, we will discuss a simple but robust method of making water-soluble CdS:Mn/ZnS Qdots at the room-temperature. Two different water-soluble biomolecules, the N-acetyl cysteine (NAC) and the glutathione (GSH) were used as surface coating ligands. This is a singlestep, one-pot synthesis where the Qdot nanocrystals were grown in the presence of the biomolecules. These Qdots were characterized by fluorescence spectroscopy. Stability of the GSH coated Qdots and the NAC coated Qdots were studied by treating with ethylenediaminetetraacetic acid (EDTA, a strong chelating agent for Zn and Cd ions). Our results show that fluorescence properties of Qdots are affected by the type of surface coated ligands. In comparison to the GSH coated Qdots, the NAC coated Qdots show broad but strong emission towards near infra-red region. When treated with EDTA, fluorescence property of the GSH coated Qdot was affected less than the NAC coated Qdots. This preliminary study shows that NAC coated Qdots could potentially be used to develop activatable ("OFF/ON") probes for potential deep-tissue imaging applications. Similarly, the GSH coated Qdots could be applied for probing desired analytes or for bioimaging purposes in environmentally harsh conditions.

  18. Au@Ag/Au nanoparticles assembled with activatable aptamer probes as smart ``nano-doctors'' for image-guided cancer thermotherapy

    NASA Astrophysics Data System (ADS)

    Shi, Hui; Ye, Xiaosheng; He, Xiaoxiao; Wang, Kemin; Cui, Wensi; He, Dinggeng; Li, Duo; Jia, Xuekun

    2014-07-01

    Although nanomaterial-based theranostics have increased positive expectations from cancer treatment, it remains challenging to develop in vivo ``nano-doctors'' that provide high-contrast image-guided site-specific therapy. Here we designed an activatable theranostic nanoprobe (ATNP) via self-assembly of activatable aptamer probes (AAPs) on Au@Ag/Au nanoparticles (NPs). As both quenchers and heaters, novel Au@Ag/Au NPs were prepared, showing excellent fluorescence quenching and more effective near-infrared photothermal therapy than Au nanorods. The AAP comprised a thiolated aptamer and a fluorophore-labeled complementary DNA; thus, the ATNP with quenched fluorescence in the free state could realize signal activation through target binding-induced conformational change of the AAP, and then achieve on-demand treatment under image-guided irradiation. By using S6 aptamer as the model, in vitro and in vivo studies of A549 lung cancer verified that the ATNP greatly improved imaging contrast and specific destruction, suggesting a robust and versatile theranostic strategy for personalized medicine in future.Although nanomaterial-based theranostics have increased positive expectations from cancer treatment, it remains challenging to develop in vivo ``nano-doctors'' that provide high-contrast image-guided site-specific therapy. Here we designed an activatable theranostic nanoprobe (ATNP) via self-assembly of activatable aptamer probes (AAPs) on Au@Ag/Au nanoparticles (NPs). As both quenchers and heaters, novel Au@Ag/Au NPs were prepared, showing excellent fluorescence quenching and more effective near-infrared photothermal therapy than Au nanorods. The AAP comprised a thiolated aptamer and a fluorophore-labeled complementary DNA; thus, the ATNP with quenched fluorescence in the free state could realize signal activation through target binding-induced conformational change of the AAP, and then achieve on-demand treatment under image-guided irradiation. By using S6 aptamer as

  19. Redoxable heteronanocrystals functioning magnetic relaxation switch for activatable T1 and T2 dual-mode magnetic resonance imaging.

    PubMed

    Kim, Myeong-Hoon; Son, Hye-Young; Kim, Ga-Yun; Park, Kwangyeol; Huh, Yong-Min; Haam, Seungjoo

    2016-09-01

    T1/T2 dual-mode magnetic resonance (MR) contrast agents (DMCAs) have gained much attention because of their ability to improve accuracy by providing two pieces of complementary information with one instrument. However, most of these agents are "always ON" systems that emit MR contrast regardless of their interaction with target cells or biomarkers, which may result in poor target-to-background ratios. Herein, we introduce a rationally designed magnetic relaxation switch (MGRS) for an activatable T1/T2 dual MR imaging system. Redox-responsive heteronanocrystals, consisting of a superparamagnetic Fe3O4 core and a paramagnetic Mn3O4 shell, are synthesized through seed-mediated growth and subsequently surface-modified with polysorbate 80. The Mn3O4 shell acts as both a protector of Fe3O4 in aqueous environments to attenuate T2 relaxation and as a redoxable switch that can be activated in intracellular reducing environments by glutathione. This simultaneously generates large amounts of magnetically decoupled Mn(2+) ions and allows Fe3O4 to interact with the water protons. This smart nanoplatform shows an appropriate hydrodynamic size for the EPR effect (10-100 nm) and demonstrates biocompatibility. Efficient transitions of OFF/ON dual contrast effects are observed by in vitro imaging and MR relaxivity measurements. The ability to use these materials as DMCAs is demonstrated via effective passive tumor targeting for T1- and T2-weighted MR imaging in tumor-bearing mice. PMID:27281684

  20. Activatable hyaluronic acid nanoparticle as a theranostic agent for optical/photoacoustic image-guided photothermal therapy.

    PubMed

    Zhang, Liwen; Gao, Shi; Zhang, Fan; Yang, Kai; Ma, Qingjie; Zhu, Lei

    2014-12-23

    Photothermal therapy (PTT) is an emerging treatment modality that is under intensive preclinical investigations for the treatment of various medical conditions, including cancer. However, the lack of targeting function of PTT agents hampers its clinical application. An effective and nontoxic delivery vehicle that can carry PTT agents into tumor areas is still needed urgently. In this study, we developed a multifunctional nanocomposite by loading copper sulfide (CuS) into Cy5.5-conjugated hyaluronic acid nanoparticles (HANP), obtaining an activatable Cy5.5-HANP/CuS (HANPC) nanocomposite. In this system, Cy5.5 fluorescent signal is quenched by CuS inside the particle until the whole nanocomposite is degraded by hyaluronidase present in tumor, giving strong fluorescence signals delineating the tumor. Importantly, CuS with strong NIR absorbance appears to be an excellent contrast agent for photoacoustic (PA) imaging and an effective PTT agent. After intravenous administration of HANPC into SCC7 tumor-bearing mice, high fluorescence and PA signals were observed in the tumor area over time, which peaked at the 6 h time point (tumor-to-normal tissue ratio of 3.25±0.25 for optical imaging and 3.8±0.42 for PA imaging). The tumors were then irradiated with a laser, and a good tumor inhibition rate (89.74% on day 5) was observed. Our studies further encourage application of this HA-based multifunctional nanocomposite for image-guided PTT in biomedical applications, especially in cancer theranostics. PMID:25402600

  1. Novel 19F Activatable Probe for the Detection of Matrix Metalloprotease-2 Activity by MRI/MRS

    PubMed Central

    2015-01-01

    Matrix metalloproteases (MMPs) have been found to be highly expressed in a variety of malignant tumor tissues. Noninvasive visualization of MMP activity may play an important role in the diagnosis of MMP associated diseases. Here we report the design and synthesis of a set of fluorine-19 dendron-based magnetic resonance imaging (MRI) probes for real-time imaging of MMP-2 activity. The probes have the following features: (a) symmetrical fluorine atoms; (b) the number of fluorine atoms can be increased through facile chemical modification; (c) readily accessible peptide sequence as the MMP-2 substrate; (d) activatable 19F signal (off/on mode) via paramagnetic metal ion incorporation. Following optimization for water solubility, one of the probes was selected to evaluate MMP-2 activity by 19F magnetic resonance spectroscopy (MRS). Our results showed that the fluorine signal increased by 8.5-fold in the presence of MMP-2. The specific cleavage site was verified by mass spectrometry. The selected probe was further applied to detect secreted MMP-2 activity of living SCC7 squamous cell carcinoma cells. The fluorine signal was increased by 4.8-fold by MRS analysis after 24 h incubation with SCC7 cells. This type of fluorine probe can be applied to evaluate other enzyme activities by simply tuning the substrate structures. This symmetrical fluorine dendron-based probe design extends the scope of the existing 19F MRI agents and provides a simple but robust method for real-time 19F MRI application. PMID:25271556

  2. Preclinical evaluation of light-activatable, bispecific anti-human CD3 antibody conjugates as anti-ovarian cancer therapeutics

    PubMed Central

    Dessi, John

    2009-01-01

    The administration of anti-CD3 antibodies, either unmodified or in bispecific formats, has been shown to kill tumors. However, their activity needs to be carefully controlled. We have approached this problem by inhibiting their anti-CD3 activity until it is required. Folated anti-human CD3 antibody bispecific conjugates were therefore synthesised in which the folate portion of the conjugates remained free to bind to folate receptor (FR) expressing cancer cells, whilst their anti-CD3 activity was reversibly inhibited. On irradiation with UV-A light, the T-cell binding activity of the anti-CD3 antibody can be restored only when and where it is required, i.e., adjacent to a tumor. Conjugate bound to FR expressed on normal tissues in other parts of the body remains inactive. This report describes the preclinical in vivo testing of these conjugates in transgenic mice whose T-cells express human CD3 molecules. When the ‘cloaked’ conjugates were reactivated in the region of the primary tumor, both primary tumor growth and liver metastasis were markedly reduced. That the deliberate targeting of T-cell activity locally to the primary tumor also resulted in reduced distant metastatic growth was a key finding. Light-activatable bispecific antibody conjugates similar to those described here offer a means to control T-cell targeting with a much higher degree of specificity to tumors because they minimize potentially dangerous and unwanted side effects in non-illuminated areas. The addition of light-specific targeting to the inherent tumor specific targeting of therapeutic antibody conjugates could result in the development of safer treatments for patients. PMID:20068406

  3. An activatable multimodal/multifunctional nanoprobe for direct imaging of intracellular drug delivery

    PubMed Central

    Mitra, Rajendra N.; Doshi, Mona; Zhang, Xiaolei; Tyus, Jessica C.; Bengtsson, Niclas; Fletcher, Steven; Page, Brent D. G.; Turkson, James; Gesquiere, Andre J.; Gunning, Patrick T.; Walter, Glenn A.; Santra, Swadeshmukul

    2011-01-01

    Multifunctional nanoparticles integrated with imaging modalities (such as magnetic resonance and optical) and therapeutic drugs are promising candidates for future cancer diagnostics and therapy. While targeted drug delivery and imaging of tumor cells have been the major focus in engineering nanoparticle probes, no extensive efforts have been made towards developing sensing probes that can confirm and monitor intra-cellular drug release events. Here, we present quantum dot (Qdot)-iron oxide (IO) based multimodal/multifunctional nanocomposite probe that is optically and magnetically imageable, targetable and capable of reporting on intra-cellular drug release events. Specifically, the probe consists of a superparamagnetic iron oxide nanoparticle core (IONP) decorated with satellite CdS:Mn/ZnS Qdots where the Qdots themselves are further functionalized with STAT3 inhibitor (an anti-cancer agent), vitamin folate (as targeting motif) and m-polyethylene glycol (m-PEG, a hydrophilic dispersing agent). The Qdot luminescence is quenched in this nanocomposite probe (“OFF” state) due to combined electron/energy transfer mediated quenching processes involving IONP, folate and STAT3 agents. Upon intracellular uptake, the probe is exposed to the cytosolic glutathione (GSH) containing environment resulting in restoration of the Qdot luminescence (“ON” state), which reports on uptake and drug release. Probe functionality was validated using fluorescence and MR measurements as well as in vitro studies using cancer cells that overexpress folate receptors. PMID:22078810

  4. Therapeutic potential of an orally effective small molecule inhibitor of plasminogen activator inhibitor for asthma.

    PubMed

    Liu, Rui-Ming; Eldridge, Stephanie; Watanabe, Nobuo; Deshane, Jessy; Kuo, Hui-Chien; Jiang, Chunsun; Wang, Yong; Liu, Gang; Schwiebert, Lisa; Miyata, Toshio; Thannickal, Victor J

    2016-02-15

    Asthma is one of the most common respiratory diseases. Although progress has been made in our understanding of airway pathology and many drugs are available to relieve asthma symptoms, there is no cure for chronic asthma. Plasminogen activator inhibitor 1 (PAI-1), a primary inhibitor of tissue-type and urokinase-type plasminogen activators, has pleiotropic functions besides suppression of fibrinolysis. In this study, we show that administration of TM5275, an orally effective small-molecule PAI-1 inhibitor, 25 days after ovalbumin (OVA) sensitization-challenge, significantly ameliorated airway hyperresponsiveness in an OVA-induced chronic asthma model. Furthermore, we show that TM5275 administration significantly attenuated OVA-induced infiltration of inflammatory cells (neutrophils, eosinophils, and monocytes), the increase in the levels of OVA-specific IgE and Th2 cytokines (IL-4 and IL-5), the production of mucin in the airways, and airway subepithelial fibrosis. Together, the results suggest that the PAI-1 inhibitor TM5275 may have therapeutic potential for asthma through suppressing eosinophilic allergic response and ameliorating airway remodeling. PMID:26702150

  5. Extending the cross-linking/mass spectrometry strategy: Facile incorporation of photo-activatable amino acids into the model protein calmodulin in Escherichia coli cells.

    PubMed

    Piotrowski, Christine; Ihling, Christian H; Sinz, Andrea

    2015-11-01

    Photo-induced cross-linking is a highly promising technique to investigate protein conformations and protein-protein interactions in their natural cellular environment. One strategy relies on the non-directed incorporation of diazirine-containing photo-activatable amino acids into proteins and a subsequent cross-link formation induced by UV-A irradiation. The advantage of this photo-cross-linking strategy is that it is not restricted to lysine residues and that hydrophobic regions in proteins can also be targeted, which is advantageous for investigating membrane proteins. Here, we present a simplified protocol that relies on the use of mineral salts medium without any special requirements for the incorporation of photo-methionines into proteins in Escherichia coli cells. The possibility to perform these experiments in E. coli is especially valuable as it is the major system for recombinant protein production. The method is exemplified for the Ca(2+) regulating protein calmodulin containing nine methionines, which were found to be replaced by their photo-activatable analogues. Our protocol allows the facile and stochastic incorporation of photo-methionines as the basis for conducting photo-cross-linking experiments in E. coli in an efficient manner. PMID:25726908

  6. A Cell-Based Internalization and Degradation Assay with an Activatable Fluorescence–Quencher Probe as a Tool for Functional Antibody Screening

    PubMed Central

    Liu, Peter Corbett; Shen, Yang; Snavely, Marshall D.; Hiraga, Kaori

    2015-01-01

    For the development of therapeutically potent anti-cancer antibody drugs, it is often important to identify antibodies that internalize into cells efficiently, rather than just binding to antigens on the cell surface. Such antibodies can mediate receptor endocytosis, resulting in receptor downregulation on the cell surface and potentially inhibiting receptor function and tumor growth. Also, efficient antibody internalization is a prerequisite for the delivery of cytotoxic drugs into target cells and is critical for the development of antibody–drug conjugates. Here we describe a novel activatable fluorescence–quencher pair to quantify the extent of antibody internalization and degradation in the target cells. In this assay, candidate antibodies were labeled with a fluorescent dye and a quencher. Fluorescence is inhibited outside and on the surface of cells, but activated upon endocytosis and degradation of the antibody. This assay enabled the development of a process for rapid characterization of candidate antibodies potentially in a high-throughput format. By employing an activatable secondary antibody, primary antibodies in purified form or in culture supernatants can be screened for internalization and degradation. Because purification of candidate antibodies is not required, this method represents a direct functional screen to identify antibodies that internalize efficiently early in the discovery process. PMID:26024945

  7. A Cell-Based Internalization and Degradation Assay with an Activatable Fluorescence-Quencher Probe as a Tool for Functional Antibody Screening.

    PubMed

    Li, Yan; Liu, Peter Corbett; Shen, Yang; Snavely, Marshall D; Hiraga, Kaori

    2015-08-01

    For the development of therapeutically potent anti-cancer antibody drugs, it is often important to identify antibodies that internalize into cells efficiently, rather than just binding to antigens on the cell surface. Such antibodies can mediate receptor endocytosis, resulting in receptor downregulation on the cell surface and potentially inhibiting receptor function and tumor growth. Also, efficient antibody internalization is a prerequisite for the delivery of cytotoxic drugs into target cells and is critical for the development of antibody-drug conjugates. Here we describe a novel activatable fluorescence-quencher pair to quantify the extent of antibody internalization and degradation in the target cells. In this assay, candidate antibodies were labeled with a fluorescent dye and a quencher. Fluorescence is inhibited outside and on the surface of cells, but activated upon endocytosis and degradation of the antibody. This assay enabled the development of a process for rapid characterization of candidate antibodies potentially in a high-throughput format. By employing an activatable secondary antibody, primary antibodies in purified form or in culture supernatants can be screened for internalization and degradation. Because purification of candidate antibodies is not required, this method represents a direct functional screen to identify antibodies that internalize efficiently early in the discovery process. PMID:26024945

  8. Effects of hirudin-induced activation of nonenzymatic fibrinolysis during immobilization stress

    NASA Technical Reports Server (NTRS)

    Shapiro, F. B.; Baskova, I. P.; Cherkesova, L. U.; Lyapina, L. A.; Goldovskaya, M. D.

    1980-01-01

    The specific inhibitor of thrombin, hirudin, was used for studying the mechanism of the activating effect of ACTH and adrenalin on nonenzymatic fibrinolytic activity (NEFA), the latter characterizing the function of the anticoagulation system (ACS). Simultaneous administration of ACTH and hirudin to animals subjected to immobilization stress did not reduce the effect of ACTH on NEFA, while simultaneous administration of adrenalin and hirudin revealed a diminished effect of the former. This suggests different mechanisms of ACTH and adrenalin effects upon NEFA: the stimulating effect of norepinephrine is realized through throminogenesis followed by activation of the ACS function and by increased NEFA and therefore inhibitable by hirudin which forms an inactive complex with thrombin. In fact the stimulating effect of ACTH upon NEFA is brought about specifically by another route than thrombinogenesis and thus occurs in the presence of hirudin. Hirudin itself has no effect upon NEFA.

  9. Unraveling the Pivotal Role of Bradykinin in ACE Inhibitor Activity.

    PubMed

    Taddei, Stefano; Bortolotto, L

    2016-10-01

    Historically, the first described effect of an angiotensin converting enzyme (ACE) inhibitor was an increased activity of bradykinin, one of the substrates of ACE. However, in the subsequent years, molecular models describing the mechanism of action of ACE inhibitors in decreasing blood pressure and cardiovascular risk have focused mostly on the renin-angiotensin system. Nonetheless, over the last 20 years, the importance of bradykinin in regulating vasodilation, natriuresis, oxidative stress, fibrinolysis, inflammation, and apoptosis has become clearer. The affinity of ACE appears to be higher for bradykinin than for angiotensin I, thereby suggesting that ACE inhibitors may be more effective inhibitors of bradykinin degradation than of angiotensin II production. Data describing the effect of ACE inhibition on bradykinin signaling support the hypothesis that the most cardioprotective benefits attributed to ACE inhibition may be due to increased bradykinin signaling rather than to decreased angiotensin II signaling, especially when high dosages of ACE inhibitors are considered. In particular, modulation of bradykinin in the endothelium appears to be a major target of ACE inhibition. These new mechanistic concepts may lead to further development of strategies enhancing the bradykinin signaling. PMID:27260014

  10. Cross-talk between inflammation,coagulation/fibrinolysis and vascular access in hemodialysis patients.

    PubMed

    Costa, E; Rocha, S; Rocha-Pereira, P; Castro, E; Reis, F; Teixeira, F; Miranda, V; Do Sameiro Faria, M; Loureiro, A; Quintanilha, A; Belo, L; Santos-Silva, A

    2008-01-01

    This work aimed to study the association between fibrinolytic/endothelial cell function and inflammatory markers in chronic kidney disease (CKD) patients undergoing hemodialysis (HD) and recombinant human erythropoietin (rhEPO) therapies, and its relationship with the type of vascular access (VA) used for the HD procedure. As fibrinolytic/endothelial cell function markers we evaluated plasminogen activator inhibitor type-1 (PAI-1), tissue plasminogen activator (tPA) and D-dimers, and as inflammatory markers; C-reactive protein (CRP), soluble interleukin (IL)-2 receptor (s-IL2R), IL-6 and serum albumin levels. The study was performed in 50 CKD patients undergoing regular HD, 11 with a central venous dialysis catheter (CVC) and 39 with an arteriovenous fistula (AVF), and in 25 healthy controls. Compared to controls, CKD patients presented with significantly higher levels of CRP, s-IL2R, IL-6 and D-dimers, and significantly lower levels of PAI-1. The tPA/PAI-1 ratio was significantly higher in CKD patients. We also found statistical significant correlations in CKD patients between D-dimerslevels and inflammatory markers: CRP, albumin, s-IL2R and IL-6. When comparing the two groups of CKD patients, we found that those with a CVC presented statistically significant lower levels of hemoglobin concentration and albumin, and higher levels of CRP, IL-6, D-dimers and tPA. Our results showed an association between fibrinolytic/ endothelial cell function and increased inflammatory markers in CKD patients. The increased levels of Ddimer, tPA and inflammatory markers in CKD patients using a CVC, led us to propose a relationship between the type of VA chosen for HD, and the risk of thrombogenesis. PMID:19085894

  11. Microscale receiver operating characteristic analysis of micrometastasis recognition using activatable fluorescent probes indicates leukocyte imaging as a critical factor to enhance accuracy

    NASA Astrophysics Data System (ADS)

    Spring, Bryan Q.; Palanisami, Akilan; Hasan, Tayyaba

    2014-06-01

    Molecular-targeted probes are emerging with applications for optical biopsy of cancer. An underexplored potential clinical use of these probes is to monitor residual cancer micrometastases that escape cytoreductive surgery and chemotherapy. Here, we show that leukocytes, or white blood cells, residing in nontumor tissues-as well as those infiltrating micrometastatic lesions-uptake cancer cell-targeted, activatable immunoconjugates nonspecifically, which limits the accuracy and resolution of micrometastasis recognition using these probes. Receiver operating characteristic analysis of freshly excised tissues from a mouse model of peritoneal carcinomatosis suggests that dual-color imaging, adding an immunostain for leukocytes, offers promise for enabling accurate recognition of single cancer cells. Our results indicate that leukocyte identification improves micrometastasis recognition sensitivity and specificity from 92 to 93%-for multicellular metastases >20 to 30 μm in size-to 98 to 99.9% for resolving metastases as small as a single cell.

  12. A Comparison between Mechanical Thrombectomy and Intra-arterial Fibrinolysis in Acute Basilar Artery Occlusion: Single Center Experiences

    PubMed Central

    Jung, Seunguk; Jung, Cheolkyu; Bae, Yun Jung; Choi, Byung Se; Kim, Jae Hyoung; Lee, Sang-Hwa; Chang, Jun Young; Kim, Beom Joon; Han, Moon-Ku; Bae, Hee-Joon; Kwon, Bae Ju; Cha, Sang-Hoon

    2016-01-01

    Background and Purpose Recent advances in intra-arterial techniques and thrombectomy devices lead to high rate of recanalization. However, little is known regarding the effect of the evolvement of endovascular revascularization therapy (ERT) in acute basilar artery occlusion (BAO). We compared the outcome of endovascular mechanical thrombectomy (EMT) versus intra-arterial fibrinolysis (IAF)-based ERT in patients with acute BAO. Methods After retrospectively reviewed a registry of consecutive patients with acute ischemic stroke who underwent ERT from September 2003 to February 2015, 57 patients with acute BAO within 12 hours from stroke onset were enrolled. They were categorized as an IAF group (n=24) and EMT group (n=33) according to the primary technical option. We compared the procedural and clinical outcomes between the groups. Results The time from groin puncture to recanalization was significantly shorter in the EMT group than in the IAF group (48.5 [25.3 to 87.8] vs. 92 [44 to 179] minutes; P=0.02) The rate of complete recanalization was significantly higher in the EMT group than in the IAF group (87.9% vs 41.7%; P<0.01). The good outcome of the modified Rankin Scale score≤2 at 3 months was more frequent in the EMT group than in the IAF group, but it was not statistically significant (39.4% vs 16.7%; P=0.06). Conclusions EMT-based ERT in patients with acute BAO is superior to IAF-based ERT in terms of the reduction of time from groin puncture to recanalization and the improvement of the rate of complete recanalization. PMID:27283281

  13. Hyaluronic acid-shelled acid-activatable paclitaxel prodrug micelles effectively target and treat CD44-overexpressing human breast tumor xenografts in vivo.

    PubMed

    Zhong, Yinan; Goltsche, Katharina; Cheng, Liang; Xie, Fang; Meng, Fenghua; Deng, Chao; Zhong, Zhiyuan; Haag, Rainer

    2016-04-01

    The therapeutic efficacy of nanoscale anticancer drug delivery systems is severely truncated by their low tumor-targetability and inefficient drug release at the target site. Here, we report the design and development of novel endosomal pH-activatable paclitaxel prodrug micelles based on hyaluronic acid-b-dendritic oligoglycerol (HA-dOG-PTX-PM) for active targeting and effective treatment of CD44-overexpressing human breast cancer xenografts in nude mice. HA-dOG-PTX-PM had a high drug content of 20.6 wt.% and an average diameter of 155 nm. The release of PTX was slow at pH 7.4 but greatly accelerated at endosomal pH. MTT assays, flow cytometry and confocal experiments showed that HA-dOG-PTX-PM possessed a high targetability and antitumor activity toward CD44 receptor overexpressing MCF-7 human breast cancer cells. The in vivo pharmacokinetics and biodistribution studies showed that HA-dOG-PTX-PM had a prolonged circulation time in the nude mice and a remarkably high accumulation in the MCF-7 tumor (6.19%ID/g at 12 h post injection). Interestingly, HA-dOG-PTX-PM could effectively treat mice bearing MCF-7 human breast tumor xenografts with little side effects, resulting in complete inhibition of tumor growth and a 100% survival rate over an experimental period of 55 days. These results indicate that hyaluronic acid-shelled acid-activatable PTX prodrug micelles have a great potential for targeted chemotherapy of CD44-positive cancers. PMID:26851390

  14. The efficacy and safety of complete pericardial drainage by means of intrapericardial fibrinolysis for the prevention of complications of pericardial effusion: a systematic review protocol

    PubMed Central

    Kakia, Aloysious; Wiysonge, Charles S; Ochodo, Eleanor A; Awotedu, Abolade A; Ristic, Arsen D; Mayosi, Bongani M

    2016-01-01

    Introduction Intrapericardial fibrinolysis has been proposed as a means of preventing complications of pericardial effusion such as cardiac tamponade, persistent and recurrent pericardial effusion, and pericardial constriction. There is a need to understand the efficacy and safety of this procedure because it shows promise. Methods and analysis We aim to assess the effects of intrapericardial fibrinolysis in the treatment of pericardial effusion. We will search PubMed, the Cochrane Library, African Journals online, Cumulative Index to Nursing and Allied Health Literature, Trip database, Clinical trials.gov and the WHO International Clinical Trials Registry Platform for studies that evaluate the efficacy and/or safety of complete pericardial fluid drainage by intrapericardial fibrinolysis irrespective of study design, geographical location, language, age of participants, aetiology of pericarditis or types of fibrinolytics. Two authors will do the search independently, screen the search outputs for potentially eligible studies and assess whether the studies meet the inclusion criteria. Discrepancies between the two authors will be resolved through discussion and arbitration by a third author. Data from the selected studies shall be extracted using a standardised data collection form which will be piloted before use. The methodological quality of studies will be assessed using the Cochrane Collaboration's tools for assessing risk of bias for experimental studies and non-randomised studies, respectively. The primary meta-analysis will use random effects models due to expected interstudy heterogeneity. Dichotomous data will be analysed using relative risk and continuous with data mean differences, both with 95% CIs. Ethics and dissemination Approval by an ethics committee is not required for this study as it is a protocol for a systematic review of published studies. The results will be disseminated through a conference presentation and peer-reviewed publication. Review

  15. Addition of Arsenic Trioxide into Induction Regimens Could Not Accelerate Recovery of Abnormality of Coagulation and Fibrinolysis in Patients with Acute Promyelocytic Leukemia

    PubMed Central

    Zhang, Ye; Wu, SiJing; Luo, Dan; Zhou, JianFeng; Li, DengJu

    2016-01-01

    Aim All-trans retinoic acid combined to anthracycline-based chemotherapy is the standard regimen of acute promyelocytic leukemia. The advent of arsenic trioxide has contributed to improve the anti-leukemic efficacy in acute promyelocytic leukemia. The objectives of the current study were to evaluate if dual induction by all-trans retinoic acid and arsenic trioxide could accelerate the recovery of abnormality of coagulation and fibrinolysis in patients with acute promyelocytic leukemia. Methods Retrospective analysis was performed in 103 newly-diagnosed patients with acute promyelocytic leukemia. Hemostatic variables and the consumption of component blood were comparably analyzed among patients treated by different induction regimen with or without arsenic trioxide. Results Compared to patients with other subtypes of de novo acute myeloid leukemia, patients with acute promyelocytic leukemia had lower platelet counts and fibrinogen levels, significantly prolonged prothrombin time and elevated D-dimers (P<0.001). Acute promyelocytic leukemia patients with high or intermediate risk prognostic stratification presented lower initial fibrinogen level than that of low-risk group (P<0.05). After induction treatment, abnormal coagulation and fibrinolysis of patients with acute promyelocytic leukemia was significantly improved before day 10. The recovery of abnormal hemostatic variables (platelet, prothrombin time, fibrinogen and D-dimer) was not significantly accelerated after adding arsenic trioxide in induction regimens; and the consumption of transfused component blood (platelet and plasma) did not dramatically change either. Acute promyelocytic leukemia patients with high or intermediate risk prognostic stratification had higher platelet transfusion demands than that of low-risk group (P<0.05). Conclusions Unexpectedly, adding arsenic trioxide could not accelerate the recovery of abnormality of coagulation and fibrinolysis in acute promyelocytic leukemia patients who

  16. Antifibrinolytic Mechanisms in Acute Airway Injury after Sulfur Mustard Analog Inhalation

    PubMed Central

    Ahmad, Aftab; Veress, Livia A.; Rioux, Jacqueline S.; Garlick, Rhonda B.; White, Carl W.

    2014-01-01

    Acute lung injury in response to mustard gas (sulfur mustard [SM]) inhalation results in formation of fibrin casts, which obstruct the airway. The objective of this study was to identify fibrinolytic pathways that could be contributing to the persistence of airway casts after SM exposure. Rats were exposed to the SM analog, 2-chloroethyl ethyl sulfide, via nose-only aerosol inhalation. At 4 and 18 hours after exposure, animals were killed and airway–capillary leak estimated by measuring bronchoalveolar lavage fluid (BALF) protein and IgM content. The fibrin clot–degrading and plasminogen-activating capabilities of BALF were also assessed by activity assays, whereas Western blotting was used to determine the presence and activities of plasminogen activator inhibitor-1, thrombin activatable fibrinolytic inhibitor and α2-antiplasmin. Measurement of tissue-specific steady-state mRNA levels was also conducted for each fibrinolytic inhibitor to assess whether its synthesis occurs in lung or at extrapulmonary sites. The results of this study demonstrate that fibrin-degrading and plasminogen-activating capabilities of the airways become impaired during the onset of 2-chloroethyl ethyl sulfide–induced vascular leak. Findings of functionally active reservoirs of plasminogen activator inhibitor-1, thrombin activatable fibrinolysis inhibitor, and α2-antiplasmin in BALF indicate that airway fibrinolysis is inhibited at multiple levels in response to SM. PMID:24796565

  17. Optimization of Cyclic Plasmin Inhibitors: From Benzamidines to Benzylamines.

    PubMed

    Hinkes, Stefan; Wuttke, André; Saupe, Sebastian M; Ivanova, Teodora; Wagner, Sebastian; Knörlein, Anna; Heine, Andreas; Klebe, Gerhard; Steinmetzer, Torsten

    2016-07-14

    New macrocyclic plasmin inhibitors based on our previously optimized P2-P3 core segment have been developed. In the first series, the P4 residue was modified, whereas the 4-amidinobenzylamide in P1 position was maintained. The originally used P4 benzylsulfonyl residue could be replaced by various sulfonyl- or urethane-like protecting groups. In the second series, the P1 benzamidine was modified and a strong potency and excellent selectivity was retained by incorporation of p-xylenediamine. Several analogues inhibit plasmin in the subnanomolar range, and their potency against related trypsin-like serine proteases including trypsin itself could be further reduced. Selected derivatives have been tested in a plasma fibrinolysis assay and are more effective than the reference inhibitor aprotinin. The crystal structure of one inhibitor was determined in complex with trypsin. The binding mode reveals a sterical clash of the inhibitor's linker segment with the 99-hairpin loop of trypsin, which is absent in plasmin. PMID:27280436

  18. Proteasome inhibitors.

    PubMed

    Teicher, Beverly A; Tomaszewski, Joseph E

    2015-07-01

    Proteasome inhibitors have a 20 year history in cancer therapy. The first proteasome inhibitor, bortezomib (Velcade, PS-341), a break-through multiple myeloma treatment, moved rapidly through development from bench in 1994 to first approval in 2003. Bortezomib is a reversible boronic acid inhibitor of the chymotrypsin-like activity of the proteasome. Next generation proteasome inhibitors include carfilzomib and oprozomib which are irreversible epoxyketone proteasome inhibitors; and ixazomib and delanzomib which are reversible boronic acid proteasome inhibitors. Two proteasome inhibitors, bortezomib and carfilzomib are FDA approved drugs and ixazomib and oprozomib are in late stage clinical trials. All of the agents are potent cytotoxics. The disease focus for all the proteasome inhibitors is multiple myeloma. This focus arose from clinical observations made in bortezomib early clinical trials. Later preclinical studies confirmed that multiple myeloma cells were indeed more sensitive to proteasome inhibitors than other tumor cell types. The discovery and development of the proteasome inhibitor class of anticancer agents has progressed through a classic route of serendipity and scientific investigation. These agents are continuing to have a major impact in their treatment of hematologic malignancies and are beginning to be explored as potential treatment agent for non-cancer indications. PMID:25935605

  19. Common variation in the C-terminal region of the fibrinogen beta-chain: effects on fibrin structure, fibrinolysis and clot rigidity.

    PubMed

    Ajjan, Ramzi; Lim, Bernard C B; Standeven, Kristina F; Harrand, Robert; Dolling, Sarah; Phoenix, Fladia; Greaves, Richard; Abou-Saleh, Radwa H; Connell, Simon; Smith, D Alastair M; Weisel, John W; Grant, Peter J; Ariëns, Robert A S

    2008-01-15

    Fibrinogen BbetaArg448Lys is a common polymorphism, positioned within the carboxyl terminus of the Bbeta-chain of the molecule. Studies suggest that it is associated with severity of coronary artery disease and development of stroke. The effects of the amino acid substitution on clot structure remains controversial, and the aim of this study was to investigate the effect(s) of this polymorphism on fibrin clot structure using recombinant techniques. Permeation, turbidity, and scanning electron microscopy showed that recombinant Lys448 fibrin had a significantly more compact structure, with thin fibers and small pores, compared with Arg448. Clot stiffness, measured by means of a novel method using magnetic tweezers, was significantly higher for the Lys448 compared with the Arg448 variant. Clots made from recombinant protein variants had similar lysis rates outside the plasma environment, but when added to fibrinogen-depleted plasma, the fibrinolysis rates for Lys448 were significantly slower compared with Arg448. This study demonstrates for the first time that clots made from recombinant BbetaLys448 fibrinogen are characterized by thin fibers and small pores, show increased stiffness, and appear more resistant to fibrinolysis. Fibrinogen BbetaArg448Lys is a primary example of common genetic variation with a significant phenotypic effect at the molecular level. PMID:17925485

  20. [Progress in research of the blood coagulation system].

    PubMed

    Urano, H; Karasaki, Y; Shirahata, A

    1999-09-01

    Blood coagulation is an amplification system consisting of reactions between enzymes and zymogens. It has been illustrated as a cascade model. However, the exact mechanism by which haemostasis is achieved under physiological conditions remains to be clarified. The solving of structure-function relation of each coagulation factor, analysis of the enzymological characteristics of each reaction, analysis of the regulation mechanism of the reactions and identification of novel factors involved in coagulation reactions contribute to the understanding of this complex system. Based on these findings, some new conceptions of blood coagulation are proposed. In the model introduced in this review, the extrinsic pathway and the intrinsic pathway of the 'classical' cascade model of the blood coagulation system could not be separated, and the suppression of fibrinolysis by TAFI (thrombin activatable fibrinolysis inhibitor) during coagulation reactions is thought to be a critical process for effective haemostasis. PMID:10589463

  1. Primary angioplasty vs. fibrinolysis in very old patients with acute myocardial infarction: TRIANA (TRatamiento del Infarto Agudo de miocardio eN Ancianos) randomized trial and pooled analysis with previous studies

    PubMed Central

    Bueno, Héctor; Betriu, Amadeo; Heras, Magda; Alonso, Joaquín J.; Cequier, Angel; García, Eulogio J.; López-Sendón, José L.; Macaya, Carlos; Hernández-Antolín, Rosana; Bueno, Héctor; Hernández-Antolín, Rosana; Alonso, Joaquín J.; Betriu, Amadeo; Cequier, Angel; García, Eulogio J.; Heras, Magda; López-Sendón, José L.; Macaya, Carlos; Azpitarte, José; Sanz, Ginés; Chamorro, Angel; López-Palop, Ramón; Sionis, Alex; Arós, Fernando; García-Fernández, Eulogio; Rubio, Rafael; Hernández, Felipe; Tascón, Juan Carlos; Moreu, José; Betriu, Amadeu; Heras, Magda; Hernández-Antolín, Rosana; Fernández-Ortiz, Antonio; Morís, César; de Posada, Ignacio Sánchez; Cequier, Ángel; Esplugas, Enrique; Melgares, Rafael; Bosa, Francisco; García-González, Martín Jesús; Lezáun, Román; Carmona, José Ramón; Vázquez, José Manuel; Castro-Beiras, Alfonso; Picart, Joan García; de Rozas, José Domínguez; Fernández, José Díaz; Vázquez, Felipe Fernández; Alonso, Norberto; Zueco, José Javier; San José, José María; San Román, Alberto; Hernández, Carolina; García, José María Hernández; Alcántara, Ángel García; Bethencourt, Armando; Fiol, Miquel; Mancisidor, Xabier; Mancisidor, Xabier; Ruiz, Rafael; Hidalgo, Rafael; Sobrino, Nicolás; Maqueda, Isidoro González; Torres, Alfonso; Arós, Fernando; Amaro, Antonio; Jaquet, Michel

    2011-01-01

    Aims To compare primary percutaneous coronary intervention (pPCI) and fibrinolysis in very old patients with ST-segment elevation myocardial infarction (STEMI), in whom head-to-head comparisons between both strategies are scarce. Methods and results Patients ≥75 years old with STEMI <6 h were randomized to pPCI or fibrinolysis. The primary endpoint was a composite of all-cause mortality, re-infarction, or disabling stroke at 30 days. The trial was prematurely stopped due to slow recruitment after enroling 266 patients (134 allocated to pPCI and 132 to fibrinolysis). Both groups were well balanced in baseline characteristics. Mean age was 81 years. The primary endpoint was reached in 25 patients in the pPCI group (18.9%) and 34 (25.4%) in the fibrinolysis arm [odds ratio (OR), 0.69; 95% confidence interval (CI) 0.38–1.23; P = 0.21]. Similarly, non-significant reductions were found in death (13.6 vs. 17.2%, P = 0.43), re-infarction (5.3 vs. 8.2%, P = 0.35), or disabling stroke (0.8 vs. 3.0%, P = 0.18). Recurrent ischaemia was less common in pPCI-treated patients (0.8 vs. 9.7%, P< 0.001). No differences were found in major bleeds. A pooled analysis with the two previous reperfusion trials performed in older patients showed an advantage of pPCI over fibrinolysis in reducing death, re-infarction, or stroke at 30 days (OR, 0.64; 95% CI 0.45–0.91). Conclusion Primary PCI seems to be the best reperfusion therapy for STEMI even for the oldest patients. Early contemporary fibrinolytic therapy may be a safe alternative to pPCI in the elderly when this is not available. Clinicaltrials.gov # NCT00257309. PMID:20971744

  2. Fibrinolysis - primary or secondary

    MedlinePlus

    ... LE, Heslop HE, Weitz JI, Anastasi J, eds. Hematology: Basic Principles and Practice . 6th ed. Philadelphia, PA: ... 2/1/2016 Updated by: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. ...

  3. Far-Red Light-Activatable Prodrug of Paclitaxel for the Combined Effects of Photodynamic Therapy and Site-Specific Paclitaxel Chemotherapy.

    PubMed

    Thapa, Pritam; Li, Mengjie; Bio, Moses; Rajaputra, Pallavi; Nkepang, Gregory; Sun, Yajing; Woo, Sukyung; You, Youngjae

    2016-04-14

    Paclitaxel (PTX) is one of the most useful chemotherapeutic agents approved for several cancers, including ovarian, breast, pancreatic, and nonsmall cell lung cancer. However, it causes systemic side effects when administered parenterally. Photodynamic therapy (PDT) is a new strategy for treating local cancers using light and photosensitizer. Unfortunately, PDT is often followed by recurrence due to incomplete ablation of tumors. To overcome these problems, we prepared the far-red light-activatable prodrug of PTX by conjugating photosensitizer via singlet oxygen-cleavable aminoacrylate linker. Tubulin polymerization enhancement and cytotoxicity of prodrugs were dramatically reduced. However, once illuminated with far-red light, the prodrug effectively killed SKOV-3 ovarian cancer cells through the combined effects of PDT and locally released PTX. Ours is the first PTX prodrug that can be activated by singlet oxygen using tissue penetrable and clinically useful far-red light, which kills the cancer cells through the combined effects of PDT and site-specific PTX chemotherapy. PMID:26974508

  4. The effect of "on/off" molecular switching on the photophysical and photochemical properties of axially calixarene substituted activatable silicon(iv)phthalocyanine photosensitizers.

    PubMed

    Güngör, Ömer; Altınbaş Özpınar, Gül; Durmuş, Mahmut; Ahsen, Vefa

    2016-05-01

    Silicon(iv) phthalocyanines ( and ) bearing two calixarene groups as axial ligands were synthesized. Surprisingly, both phthalocyanines were obtained as two different isomers ( and ) depending on the distance between calixarene benzene groups and the phthalocyanine ring. DFT and TD-DFT computations were performed to model plausible structures of these isomers and to simulate electronic absorption spectra. These isomers converted into each other depending on the polarity of the used solvent, temperature and light irradiation. The photophysical and photochemical properties of each isomer were investigated in dimethylsulfoxide (DMSO) for the determination of photodynamic therapy (PDT) activities of these compounds. The more blue-shifted isomers ( and ) showed higher fluorescence quantum yields and singlet oxygen generation compared to more red-shifted counterparts ( and ). This behavior is extremely important for developing activatable photosensitizers for cancer treatment by PDT. Although these photosensitizers produce lower singlet oxygen in normal cells, they produce higher singlet oxygen (six times higher for ) in cancer cells since these photosensitizers converted to more blue-shifted isomers by using light irradiation. PMID:27052992

  5. [Variations in hemostasis and fibrinolysis during the treatment of acute myocardial infarct (AMI) with tissue-type plasminogen activator (TTPA). A study of 17 cases].

    PubMed

    Izaguirre Avila, R; Ruiz de Chávez Cervantes, A; Villavicencio, R; Gómez Trigos, A; Mar Chavira, R; Spíndola, M del C; Casanova, J M

    1993-01-01

    The aim of this trial was to estimate changes in the coagulation and fibrinolysis systems during the thrombolytic treatment with recombinant human tissue-type plasminogen activator (rt-PA) in patients with acute myocardial infarction and correlate with hemorrhagic complications. We studied 17 patients with a 3 hours-continuous systemic infusion of 100 mg of rt-PA. Prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen splits products, plasminogen, alfa-2-antiplasmin (a-2AP) and antithrombin III (AT-III) were performed before, during and after infusion. Most patients showed lengthening coagulation times. Fibrinogen and plasminogen were decreased and PDF was increased. No variations in alpha-2AP or AT-III were observed. The recuperation of fibrinogen levels occurred in 3 hours and there was hyperfibrinogenemia after day 3. No hemorrhagic complication was observed in patients with abnormalities in these coagulation or fibrinolytic tests. PMID:8347053

  6. CFTR Inhibitors

    PubMed Central

    Verkman, Alan S.; Synder, David; Tradtrantip, Lukmanee; Thiagarajah, Jay R.; Anderson, Marc O.

    2014-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) protein is a cAMP-regulated Cl− channel whose major function is to facilitate epithelial fluid secretion. Loss-of-function mutations in CFTR cause the genetic disease cystic fibrosis. CFTR is required for transepithelial fluid transport in certain secretory diarrheas, such as cholera, and for cyst expansion in autosomal dominant polycystic kidney disease. High-throughput screening has yielded CFTR inhibitors of the thiazolidinone, glycine hydrazide and quinoxalinedione chemical classes. The glycine hydrazides target the extracellular CFTR pore, whereas the thiazolidinones and quinoxalinediones act at the cytoplasmic surface. These inhibitors have been widely used in cystic fibrosis research to study CFTR function at the cell and organ levels. The most potent CFTR inhibitor has IC50 of approximately 4 nM. Studies in animal models support the development of CFTR inhibitors for antisecretory therapy of enterotoxin-mediated diarrheas and polycystic kidney disease. PMID:23331030

  7. Clinical Outcome, and Survival Between Primary Percutaneous Coronary Intervention Versus Fibrinolysis in Patients Older Than 60 Years with Acute Myocardial Infarction

    PubMed Central

    Falsoleiman, H.; Fatehi, G. H.; Dehghani, M; Shakeri, M. T.; Bayani, Baktash; Ahmadi, Mostafa; Rohani, Atoosheh

    2012-01-01

    Objective: The aim of the present study was to compare the short-term and 6-month clinical outcome, and survival in patients older than 60 years with ST-elevation myocardial infarction randomized to either primary percutaneous coronary intervention (PPCI) or thrombolysis. Materials and Methods: 82 patients with STEMI older than 60 years were randomized to either primary PCI or thrombolysis from September 2006 to August 2008. Angiograms were reviewed by two interventionalists not involved in the study. Patients randomized to primary PCI received Aspirin and 600 mg Clopidogrel. Heparin was administered in conjunction with PCI. Patients randomized to thrombolysis received Aspirin followed by streptokinase infusion for one hour. Rescue PCI was considered if there was ongoing pain and ST-segment resolution was <50% at 90 min. after initiation of thrombolysis or chest pain recurred with ST-segment elevation within 24 hours. All patients were followed up for 6 months. End points were reinfarction and cardiac death using competing-risks regression estimation. Results: The mean time from hospital admission to start of streptokinase infusion was 31 ± 15 min and door to balloon time was 70 ± 25 min. There was no significant difference between the groups in the number of deaths and reinfarctions at 6 months. As expected, the fibrinolysis group had a higher rate of revascularization and heart failure. Conclusion: The higher rates of heart failure and need for revascularization in the fibrinolysis group reinforces benefits of PPCI in patients older than 60 years. PPCI in those who are 60 years and above with AMI is safe and cost effective. PMID:23439588

  8. Circadian variation of tissue plasminogen activator and its inhibitor, von Willebrand factor antigen, and prostacyclin stimulating factor in men with ischaemic heart disease.

    PubMed Central

    Bridges, A B; McLaren, M; Scott, N A; Pringle, T H; McNeill, G P; Belch, J J

    1993-01-01

    OBJECTIVES--To determine whether plasma concentrations of tissue plasminogen activator antigen, von Willebrand factor antigen, and prostacyclin stimulating factor and plasminogen activator inhibitor activity show circadian variation in men with ischaemic heart disease. DESIGN--Blood samples were obtained every four hours for 24 hours from 10 men with ischaemic heart disease. The men were ambulant from 08:10 until 00:00 when they went to bed and they remained in bed until 08:00 the following morning. PATIENTS--Ten men with positive diagnostic exercise tolerance tests with no significant past history, who were not regularly taking any medical treatment except for glyceryl trinitrate. RESULTS--There was significant circadian variation in plasminogen activator inhibitor activity (p = 0.001) (peak value 04:00 and trough value 20:00), but not in plasma concentrations of tissue plasminogen activator antigen, von Willebrand factor, or prostacyclin stimulating factor. CONCLUSION--Men with ischaemic heart disease showed a significant circadian variation in fibrinolysis. The combination of peak values of plasminogen activator inhibitor activity and failure of plasma concentrations of tissue plasminogen activator antigen to increase in the early morning must predispose to thrombosis at this time. The circadian variation in fibrinolysis may contribute to the increased incidence of myocardial infarction in the morning. PMID:8435236

  9. Determinants of hypofibrinolysis in patients with digestive tract cancer

    PubMed Central

    Gronostaj, Katarzyna; Richter, Piotr; Nowak, Wojciech

    2016-01-01

    Introduction Recently, we demonstrated that digestive tract cancer (DTC) is associated with reduced fibrin clot permeability and impaired fibrinolysis. Aim We investigated determinants of fibrinolysis in DTC patients. Material and methods In 44 consecutive patients with DTC and 47 controls matched for age, sex, and cardiovascular risk, we evaluated fibrinolysis proteins, platelet activation markers, thrombin formation, together with plasma clot lysis time assays in the absence (CLT) and presence of carboxypeptidase potato inhibitor (CLT CPI) that blocks thrombin activatable fibrinolysis inhibitor (TAFI). Results In the DTC group CLT (by 22.3%) and CLT CPI (by 27.4%) were longer compared with controls. The DTC patients had higher plasma fibrinolysis inhibitors, plasminogen activator inhibitor 1 (PAI-1) (by 18.2%), TAFI activity (by 17.3%), and antigen (by 11.2%). The patients had markedly increased platelet markers – soluble CD40 ligand (by 338%) and P-selectin (by 97%), together with von Willebrand factor (vWF) antigen (by 61%). Thrombin-antithrombin complexes (TAT) (by 48.7%) and soluble thrombomodulin (sTM) (by 17.2%) were also increased in the DTC group (all p < 0.05). Patients with high-grade tumours (n = 26) compared with remainders (n = 18) had longer CLT, higher tissue-type plasminogen activator antigen, both TAFI antigen and activity levels, vWF, and sTM. Multiple regression analysis after adjustment for potential confounders showed that independent predictors of CLT in DTC patients were TAT, TAFI activity, and vWF. The only independent predictor of CLT CPI was TAT. Conclusions Hypofibrinolysis in DTC patients is largely driven by enhanced thrombin generation, TAFI, and endothelial injury. PMID:27350837

  10. In vivo near-infrared fluorescence imaging of FAP-expressing tumors with activatable FAP-targeted, single-chain Fv-immunoliposomes.

    PubMed

    Rüger, Ronny; Tansi, Felista L; Rabenhold, Markus; Steiniger, Frank; Kontermann, Roland E; Fahr, Alfred; Hilger, Ingrid

    2014-07-28

    Molecular and cellular changes that precede the invasive growth of solid tumors include the release of proteolytic enzymes and peptides in the tumor stroma, the recruitment of phagocytic and lymphoid infiltrates and alteration of the extracellular matrix. The reactive tumor stroma consists of a large number of myofibroblasts, characterized by high expression of fibroblast activation protein alpha (FAP). FAP, a type-II transmembrane sialoglycoprotein is an attractive target in diagnosis and therapy of several pathologic disorders especially cancer. In the underlying work, a fluorescence-activatable liposome (fluorescence-quenched during circulation and fluorescence activation upon cellular uptake), bearing specific single-chain Fv fragments directed against FAP (scFv'FAP) was developed, and its potential for use in fluorescence diagnostic imaging of FAP-expressing tumor cells was evaluated by whole body fluorescence imaging. The liposomes termed anti-FAP-IL were prepared via post-insertion of ligand-phospholipid-conjugates into preformed DY-676-COOH-containing liposomes. The anti-FAP-IL revealed a homogeneous size distribution and showed specific interaction and binding with FAP-expressing cells in vitro. The high level of fluorescence quenching of the near-infrared fluorescent dye sequestered in the aqueous interior of the liposomes enables fluorescence imaging exclusively upon uptake and degradation by cells, which results in fluorescence activation. Only FAP-expressing cells were able to take up and activate fluorescence of anti-FAP-IL in vitro. Furthermore, anti-FAP-IL accumulated selectively in FAP-expressing xenograft models in vivo, as demonstrated by blocking experiments using free scFv'FAP. The local tumor fluorescence intensities were in agreement with the intrinsic degree of FAP-expression in different xenograft models. Thus, anti-FAP-IL can serve as a suitable in vivo diagnostic tool for pathological disorders accompanied by high FAP-expression. PMID

  11. Site-specific conjugation of the quencher on peptide's N-terminal for the synthesis of a targeted non-spreading activatable optical probe.

    PubMed

    Simard, Bryan; Mironov, Gleb G; Tomanek, Boguslaw; van Veggel, Frank C J M; Abulrob, Abedelnasser

    2016-06-01

    Optical imaging offers high sensitivity and portability at low cost. The design of 'smart' or 'activatable' probes can decrease the background noise and increase the specificity of the signal. By conjugating a fluorescent dye and a compatible quencher on each side of an enzyme's substrate, the signal remains in its 'off ' state until it reaches the area where a specific enzyme is expressed. However, the signal can leak from that area unless the dye is attached to a molecule able to bind to a specific target also presented in that area. The aim of this study was to (i) specifically conjugate the quencher on the α-amino group of the peptide's N-terminus, (ii) conjugate the dye on the ε-amino group of a lysine in C-terminus, and (iii) conjugate the carboxyl group of the peptide's C-terminus to an amino group present on an antibody, using carbodiimide chemistry. The use of protecting groups, such as Boc or Fmoc, to allow site-specific conjugation, presents several drawbacks including 'on beads labeling', additional steps required for deprotection and removal from the resin, decreased yield, and dye degradation. A method of preferential labeling of α-amino N-terminal group in slightly acidic solution, proposed by Selo et al. (1996) has partially solved the problem. The present study reports improvements of the method allowing to (i) avoid the homo-bilabeling, (ii) increase the yield of the N-terminal labeling by two folds, and (iii) decrease the cost by 44-fold. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. PMID:27282138

  12. [Proteasome inhibitor].

    PubMed

    Yagi, Hideo

    2014-06-01

    The ubiquitin-proteasome system plays an essential role in degradation of eukaryotic intracellular protein, including cell cycle regulation, cell growth and proliferation, and survival. Cancer cells generally have higher level of proteasome activity compared with normal cells, suggesting proteasome inhibition could be therapeutic target in oncology. Bortezomib, the first proteasome inhibitor introduced into the clinic, is approved for the treatment of patients with multiple myeloma (MM). Although it was approved as single agent in the relapsed setting, bortezomib is now predominantly used in combination with conventional and novel targeted agents because bortezomib has demonstrated additive and synergistic activity in preclinical studies. Recently, several second-generation proteasome inhibitors, such as carfilzomib and MLN9708, have been developed and entered into clinical trials. These agents were investigated in frontline MM in combination with lenalidomide and low-dose dexamethasone. These studies demonstrated positive efficacy and safety, and it is expected that they will be approved in near future. PMID:25016815

  13. Probing intra-cellular drug release event using activatable (OFF/ON) CdS:Mn/ZnS quantum dots (Qdots): spectroscopic studies to investigate interaction of Qdots with quencher

    NASA Astrophysics Data System (ADS)

    Tharkur, Jeremy; Teblum, Andrew; Basumallick, Srijita; Shah, Rikhav; Cantarero, Karishma; Maity, Niharika; Rifai, Sara; Doshi, Mona; Gesquiere, Andre J.; Santra, Swadeshmukul

    2013-02-01

    In recent years, activatable Quantum Dots (AQdots) are gaining popularity in a number of chemical and biological sensing applications. A basic design of AQdot probes involves a suitable quencher which is capable of altering optical properties of the Qdots. In our previous studies we have shown that CdS:Mn/ZnS fluorescence can be effectively quenched using small molecule quenchers (such as dopamine, chemotherapeutic drug) as well as iron oxide nanoparticle via electron/energy transfer process. We have also shown that the quenched Qdot fluorescence can be restored when the Qdots are separated from the quencher. Using Qdot based activatable probes, we detected intracellular drug release event. Qdot fluorescence was restored upon interaction with the intracellular glutathione (GSH). In this paper, we report a GSH induced quenching of water-soluble N-Acetyl Cysteine (NAC) surface-conjugated Cds:Mn/ZnS Qdots. Quenching of NAC-Qdots was due to aggregation of Qdots in solution. This aggregation induced fluorescence quenching phenomenon resembles with the self-quenching phenomenon of traditional organic fluorescence dyes at high concentrations. UV-VIS and fluorescence emission spectroscopy data support the interaction and binding of GSH with the NAC-Qdots. Increase in particle size due to GSH induced aggregation of NAC-Qdots was confirmed by the Dynamic Light Scattering (DLS) data.

  14. The coagulopathy of heat stroke: alterations in coagulation and fibrinolysis in heat stroke patients during the pilgrimage (Haj) to Makkah.

    PubMed

    al-Mashhadani, S A; Gader, A G; al Harthi, S S; Kangav, D; Shaheen, F A; Bogus, F

    1994-10-01

    Haemostatic measurements were undertaken in 132 patients diagnosed with heat stroke during the pilgrimage to Makkah, in two successive summers of 1989-90. The control group comprised 49 patients, all pilgrims, with a wide range of clinical conditions, but without hyperpyrexia or deranged haemostasis. Heat stroke patients showed (i) significant prolongation of the prothrombin (PT), activated partial thromboplastin (aPTT) and thrombin times (TT) but normal reptilase time (RT); (ii) significant reduction in plasma levels of antithrombin III (AT-III), factor V, proteins C and S, plasminogen activator inhibitor (PAI) and platelet count; (iii) increase in plasma factor VIII, tissue plasminogen activator (t-PA) and serum FDP; (iv) no significant changes in plasma fibrinogen, plasminogen, alpha 2-antiplasmin and factors VII and X. Heat stroke patients were then grouped into those with and those without bleeding symptoms. Bleeders showed greater prolongation of the PT, aPTT and TT and significant reductions in fibrinogen, AT-III, factors V, VIII and X, plasminogen, alpha 2-antiplasmin and platelet count. Logistic regression and discriminant analysis showed that AT-III was the parameter associated most with heat stroke and reliable enough to predict its occurrence, whether or not bleeding occurred. The results indicate that activation of the haemostatic mechanism, consumptive in nature, regularly accompanies heat stroke and highlights the physiological role of AT-III in checking this activation process. PMID:7865679

  15. Autophagy inhibitors.

    PubMed

    Pasquier, Benoit

    2016-03-01

    Autophagy is a lysosome-dependent mechanism of intracellular degradation. The cellular and molecular mechanisms underlying this process are highly complex and involve multiple proteins, including the kinases ULK1 and Vps34. The main function of autophagy is the maintenance of cell survival when modifications occur in the cellular environment. During the past decade, extensive studies have greatly improved our knowledge and autophagy has exploded as a research field. This process is now widely implicated in pathophysiological processes such as cancer, metabolic, and neurodegenerative disorders, making it an attractive target for drug discovery. In this review, we will summarize the different types of inhibitors that affect the autophagy machinery and provide some potential therapeutic perspectives. PMID:26658914

  16. A comparative evaluation of assays for markers of activated coagulation and/or fibrinolysis: thrombin-antithrombin complex, D-dimer and fibrinogen/fibrin fragment E antigen.

    PubMed

    Boisclair, M D; Lane, D A; Wilde, J T; Ireland, H; Preston, F E; Ofosu, F A

    1990-04-01

    Measurements were made of levels of D-dimer in plasma and serum, thrombin-antithrombin complex (TAT) in plasma and fibrinogen/fibrin fragment E antigen (FgE) in serum in a normal healthy control group and in patients with a range of disorders associated with hypercoagulability. Levels were determined in 31 normal healthy controls, 30 patients with disseminated intravascular coagulation (DIC), 21 patients with deep venous thrombosis (DVT), 27 patients with myocardial infarction (MI), 26 patients with acute leukaemia and 56 patients with liver disease. Considering all subjects, significant correlations were established between the results of all assays. Notably high correlations (r greater than 0.9) were established between plasma and serum levels of D-dimer, between plasma levels of D-dimer and serum levels of FgE, and between serum levels of D-dimer and FgE. All assays showed very high discrimination (sensitivity) between the normal control group and patients with DIC (97-100%), but there were marked differences between the assays in sensitivity for DVT and MI. In general, the FgE assay was more sensitive than the D-dimer assay, whilst both the FgE and D-dimer assays were more sensitive than the TAT assay. The same trends were apparent in the capability of the assays to discriminate between the normal control group and patients with acute leukaemia and liver disease: disorders with an unknown prevalence of activation of coagulation/fibrinolysis. Our results indicated that measurements of fibrinogen/fibrin degradation products (FDPs) in serum were almost unaffected by artefacts. The data further suggested that the broad-spectrum FgE assay was better than the more specific D-dimer assay in detecting clinical hypercoagulability. Our study showed that, in the clinical conditions examined, FDPs were more effective markers of hypercoagulability than TAT. PMID:2189490

  17. HSP90 Inhibitor Encapsulated Photo-Theranostic Nanoparticles for Synergistic Combination Cancer Therapy

    PubMed Central

    Lin, Tzu-yin; Guo, Wenchang; Long, Qilai; Ma, Aihong; Liu, Qiangqiang; Zhang, Hongyong; Huang, Yee; Chandrasekaran, Siddarth; Pan, Chongxian; Lam, Kit S.; Li, Yuanpei

    2016-01-01

    Photodynamic therapy (PDT) is a promising non-invasive therapeutic modality that has been proposed for treating prostate cancer, but the procedure is associated with limited efficacy, tumor recurrence and photo-toxicity. In the present study, we proposed to develop a novel multifunctional nano-platform for targeted delivery of heat, reactive oxygen species (ROS) and heat shock protein 90 (Hsp90) inhibitor simultaneously for combination therapy against prostate cancer. This new nano-platform combines two newly developed entities: 1) a unique organic and biocompatible nanoporphyrin-based drug delivery system that can generate efficient heat and ROS simultaneously with light activation at the tumor sites for dual-modal photothermal- and photodynamic- therapy (PTT/PDT), and 2) new nano-formulations of Hsp90 inhibitors that can decrease the levels of pro-survival and angiogenic signaling molecules induced by phototherapy, therefore, further sensitizing cancer cells to phototherapy. Furthermore, the nanoparticles have activatable near infrared (NIR) fluorescence for optical imaging to conveniently monitor the real-time drug delivery in both subcutaneous and orthotopic mouse models bearing prostate cancer xenograft. This novel multifunctional nano-platform has great potential to improve the care of prostate cancer patients through targeted combination therapy. PMID:27375782

  18. Laboratory assessment of anti-thrombotic therapy in heart failure, atrial fibrillation and coronary artery disease: insights using thrombelastography and a micro-titre plate assay of thrombogenesis and fibrinolysis.

    PubMed

    Lau, Y C; Xiong, Q; Ranjit, P; Lip, G Y H; Blann, A D

    2016-08-01

    As heart failure, coronary artery disease and atrial fibrillation all bring a risk of thrombosis, anti-thrombotic therapy is recommended. Despite such treatment, major cardiovascular events such as myocardial infarction and stroke still occur, implying inadequate suppression of thrombus formation. Accordingly, identification of patients whose haemostasis remains unimpaired by treatment is valuable. We compared indices for assessing thrombogenesis and fibrinolysis by two different techniques in patients on different anti-thrombotic agents, i.e. aspirin or warfarin. We determined fibrin clot formation and fibrinolysis by a microplate assay and thromboelastography, and platelet marker soluble P selectin in 181 patients with acute or chronic heart failure, coronary artery disease who were taking either aspirin or warfarin. Five thromboelastograph indices and four microplate assay indices were different on aspirin versus warfarin (p < 0.05). In multivariate regression analysis, only microplate assay indices rate of clot formation and rate of clot dissolution were independently related to aspirin or warfarin use (p ≤ 0.001). Five microplate assay indices, but no thrombelastograph index, were different (p < 0.001) in aspirin users. Three microplate assay indices were different (p ≤ 0.002) in warfarin users. The microplate assay indices of lag time and rate of clot formation were abnormal in chronic heart failure patients on aspirin, suggesting increased risk of thrombosis despite anti-platelet use. Soluble P selectin was lower in patients on aspirin (p = 0.0175) but failed to correlate with any other index of haemostasis. The microplate assay shows promise as a tool for dissecting thrombogenesis and fibrinolysis in cardiovascular disease, and the impact of antithrombotic therapy. Prospective studies are required to determine a role in predicting thrombotic risk. PMID:26942726

  19. Tumor Detection at 3 Tesla with an Activatable Cell Penetrating Peptide Dendrimer (ACPPD-Gd), a T1 Magnetic Resonance (MR) Molecular Imaging Agent

    PubMed Central

    Malone, Christopher D.; Olson, Emilia S.; Mattrey, Robert F.; Jiang, Tao; Tsien, Roger Y.; Nguyen, Quyen T.

    2015-01-01

    Purpose The ability to detect small malignant lesions with magnetic resonance imaging (MRI) is limited by inadequate accumulations of Gd with standard chelate agents. To date, no T1-targeted agents have proven superiority to Gd chelates in their ability to detect small tumors at clinically relevant field strengths. Activatable cell-penetrating peptides and their Gd-loaded dendrimeric form (ACPPD-Gd) have been shown to selectively accumulate in tumors. In this study we compared the performance of ACPPD-Gd vs. untargeted Gd chelates to detect small tumors in rodent models using a clinical 3T-MR system. Materials and Methods This study was approved by the Institutional-Animal Care-and-Use Committee. 2 of 4 inguinal breast fat pads of 16 albino-C57BL/6 mice were inoculated with tumor Py8119 cells and the other 2 with saline at random. MRI at 3T was performed at 4, 9, and 14 days after inoculation on 8 mice 24-hours after injection of 0.036mmol Gd/kg (ACPPD-Gd), and before and 2–3 minutes after 0.1 mmol/kg gadobutrol on the other 8 mice. T1-weighted (T1w) tumor signal normalized to muscle, was compared among the non-contrast, gadobutrol, and ACPPD-Gd groups using ANOVA. Experienced and trainee readers blinded to experimental conditions assessed for the presence of tumor in each of the 4 breast regions. Receiver operator characteristic (ROC) curves and area-under-curve (AUC) values were constructed and analyzed. Results Tumors ≥1mm3 were iso-intense to muscle without contrast on T1w sequences. They enhanced diffusely and homogeneously by 57±20% (p<0.001) 24 hours after ACPPD-Gd and by 25±13% (p<0.001) immediately after gadobutrol. The nearly 2-fold difference was similar for small tumors (1-5mm3) (45±19% vs. 19±18%, p = 0.03). ACPPD-Gd tended to improve tumor detection by an experienced reader (AUC 0.98 vs 0.91) and significantly more for a trainee (0.93 vs. 0.82, p = 0.02) compared to gadobutrol. This improvement was more pronounced when obvious tumors (>5mm3

  20. Plasminogen Activator Inhibitor-1 Controls Vascular Integrity by Regulating VE-Cadherin Trafficking

    PubMed Central

    Daniel, Anna E.; Timmerman, Ilse; Kovacevic, Igor; Hordijk, Peter L.; Adriaanse, Luc; Paatero, Ilkka; Belting, Heinz-Georg; van Buul, Jaap D.

    2015-01-01

    Background Plasminogen activator inhibitor-1 (PAI-1), a serine protease inhibitor, is expressed and secreted by endothelial cells. Patients with PAI-1 deficiency show a mild to moderate bleeding diathesis, which has been exclusively ascribed to the function of PAI-1 in down-regulating fibrinolysis. We tested the hypothesis that PAI-1 function plays a direct role in controlling vascular integrity and permeability by keeping endothelial cell-cell junctions intact. Methodology/Principal Findings We utilized PAI-039, a specific small molecule inhibitor of PAI-1, to investigate the role of PAI-1 in protecting endothelial integrity. In vivo inhibition of PAI-1 resulted in vascular leakage from intersegmental vessels and in the hindbrain of zebrafish embryos. In addition PAI-1 inhibition in human umbilical vein endothelial cell (HUVEC) monolayers leads to a marked decrease of transendothelial resistance and disrupted endothelial junctions. The total level of the endothelial junction regulator VE-cadherin was reduced, whereas surface VE-cadherin expression was unaltered. Moreover, PAI-1 inhibition reduced the shedding of VE-cadherin. Finally, we detected an accumulation of VE-cadherin at the Golgi apparatus. Conclusions/Significance Our findings indicate that PAI-1 function is important for the maintenance of endothelial monolayer and vascular integrity by controlling VE-cadherin trafficking to and from the plasma membrane. Our data further suggest that therapies using PAI-1 antagonists like PAI-039 ought to be used with caution to avoid disruption of the vessel wall. PMID:26714278

  1. Hypofibrinolytic state in HIV-1-infected patients treated with protease inhibitor-containing highly active antiretroviral therapy.

    PubMed

    Koppel, Kristina; Bratt, Göran; Schulman, Sam; Bylund, Håkan; Sandström, Eric

    2002-04-15

    Decreased insulin sensitivity, hyperlipidemia, and body fat changes are considered as risk factors for coronary heart disease (CHD). A clustering of such factors (metabolic syndrome [MSDR]) exponentially increases the risk. Impaired fibrinolysis and increased coagulation are additional independent risk factors for CHD. We studied the effects of protease inhibitor (PI)-containing highly active antiretroviral therapy (HAART) on metabolic and hemostatic parameters in 363 HIV-infected individuals, of whom 266 were receiving PI-containing HAART and 97 were treatment naive. The fasting plasma levels of insulin, glucose, triglycerides, cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, plasminogen activator inhibitor type 1 (PAI-1), and fibrinogen were evaluated together with the areas of visceral adipose tissue and the visceral adipose tissue/subcutaneous adipose tissue area ratio. The levels of insulin, triglycerides, cholesterol, and low-density lipoprotein cholesterol; visceral adipose tissue area; low-density lipoprotein/high-density lipoprotein ratio; and visceral adipose tissue/subcutaneous adipose tissue area ratio were significantly increased in patients receiving PI-containing HAART compared with treatment-naive patients. The levels of PAI-1 and fibrinogen were significantly higher in patients receiving PI-containing HAART. PAI-1 levels were higher in individuals with MSDR but also in patients without MSDR who were receiving PI-containing HAART. PAI-1 was independently correlated to use of PI-containing HAART, triglyceride level, insulin level, and body mass index (p <.001). These findings suggest that patients receiving PI-containing HAART have decreased fibrinolysis and increased coagulability, which may thus represent additional risk factors for cardiovascular disease in this patient group. PMID:11981359

  2. Neuroendoscopic Surgery versus External Ventricular Drainage Alone or with Intraventricular Fibrinolysis for Intraventricular Hemorrhage Secondary to Spontaneous Supratentorial Hemorrhage: A Systematic Review and Meta-Analysis

    PubMed Central

    Wang, Xiaodong; She, Lei; Yan, Zhengcun; Zhang, Nan; Du, Renfei; Yan, Kaixuan; Xu, Enxi; Pang, Lujun

    2013-01-01

    Background and Purpose Although neuroendoscopy (NE) has been applied to many cerebral diseases, the effect of NE for intraventricular hemorrhage (IVH) secondary to spontaneous supratentorial hemorrhage remains controversial. The purpose of this study was to analyze the effect of NE compared with external ventricular drainage (EVD) alone or with intraventricular fibrinolysis (IVF) on the management of IVH secondary to spontaneous supratentorial hemorrhage. Methodology/ Principal Findings A systematic search of electronic databases (PubMed, EMBASE, OVID, Web of Science, The Cochrane Library, CBM, VIP, CNKI, and Wan Fang database) was performed to identify related studies published from 1970 to 2013. Randomized controlled trials (RCTs) or observational studies (OS) comparing NE with EVD alone or with IVF for the treatment of IVH were included. The quality of the included trials was assessed by Jaded scale and the Newcastle-Ottawa Scale (NOS). RevMan 5.1 software was used to conduct the meta-analysis. Results Eleven trials (5 RCTs and 6 ORs) involving 680 patients were included. The odds ratio (OR) showed a statistically significant difference between the NE + EVD and EVD + IVF groups in terms of mortality (OR, 0.31; 95% CI, 0.16-0.59; P=0.0004), effective hematoma evacuation rate (OR, 25.50, 95%CI; 14.30, 45.45; P<0.00001), good functional outcome (GFO) (OR, 4.51; (95%CI, 2.81-7.72; P<0.00001), and the ventriculo-peritoneal (VP) shunt dependence rate (OR, 0.16; 95%CI; 0.06, 0.40; P<0.0001). Conclusion Applying neuroendoscopic approach with EVD may be a better management for IVH secondary to spontaneous supratentorial hemorrhage than NE + IVF. However, there is still no concluive evidence regarding the preference of NE vs. EVD alone in the case of IVH, because insufficient data has been published thus far. This study suggests that the NE approach with EVD could become an alternative to EVD + IVF for IVH in the future. PMID:24232672

  3. Age-dependent neonatal intracerebral hemorrhage in plasminogen activator inhibitor 1 knockout mice.

    PubMed

    Leroux, Philippe; Omouendze, Priscilla L; Roy, Vincent; Dourmap, Nathalie; Gonzalez, Bruno J; Brasse-Lagnel, Carole; Carmeliet, Peter; Leroux-Nicollet, Isabelle; Marret, Stéphane

    2014-05-01

    Intracerebral-intraventricular hemorrhages (ICH/IVH) in very preterm neonates are responsible for high mortality and subsequent disabilities. In humans, tissue plasminogen activator (t-PA) initiates fibrinolysis and activates endoluminal-endothelial receptors; dysfunction of the t-PA inhibitor (PAI-1) results in recurrent hemorrhages. We used PAI-1 knockout (PAI-1) mice to examine the role of t-PA in age-dependent intracranial hemorrhages as a possible model of preterm ICH/IVH. Intracortical injection of 2 μL of phosphate-buffered saline produced a small traumatic injury and a high rate of hemorrhage in PAI-1 pups at postnatal day 3 (P3) or P5, whereas it had no effect in wild-type neonates. This resulted in white matter and cortical lesions, ventricle enlargement, hyperlocomotion, and altered cortical levels of serotonin and dopamine in the adult PAI mice. N-methyl-D-aspartate receptor blockers, plasmin- and matrix metalloproteinases inhibitors reduced hemorrhage and tissue lesions. In contrast to P3 to P5, no significant hemorrhages were induced in P10 PAI-1 pups and there were no behavioral or neurochemical alterations in adulthood. These data suggest that microvascular immaturity up to P5 in mice is a determinant factor required for t-PA-dependent vascular rupture. Neonatal PAI-1 mice could be a useful ICH/IVH model for studying the ontogenic window of vascular immaturity and vascular protection against later neurodisabilities. PMID:24709679

  4. Venous ulceration, fibrinogen and fibrinolysis.

    PubMed Central

    Leach, R. D.

    1984-01-01

    The effect of long and short-term venous hypertension upon lymph fibrinogen concentrations was studied in an attempt to explain the peri-capillary deposition of fibrin reported in patients with post-phlebitic syndromes. The clearance of radioactive fibrinogen/thrombin clots from the subcutaneous tissues of rats and human volunteers was also studied. Both long- and short-term venous hypertension were found to increase fibrinogen transport across the interstitial space by more than 600%. Not only was there evidence of fibrinolytic activity in the lymph but after long-term venous hypertension alpha 2 antiplasmin activity was also detectable. Skin biopsies from the venous hypertensive ankles showed deposition of interstitial fibrin. The clearance of radioactive fibrinogen/thrombin clots from the subcutaneous tissues of the rat was found to be delayed if the rats were given epsilon amino caproic acid but it could not be increased with stanozolol. In human subjects it was found that patients with lipodermatosclerosis had delayed clot clearance and retarded blood fibrinolytic activity when compared with normal volunteers and patients with uncomplicated varicose veins. The principle cause why tall men are more subject to ulcers than short men, Dr Young conceived to be then length of the column of blood in their veins; which by its pressure, renders the legs less able to recover when hurt by any violence. Images Fig. 1 Fig. 2 Fig. 5 PMID:6742738

  5. Proton pump inhibitors

    MedlinePlus

    Proton pump inhibitors (PPIs) are medicines that work by reducing the amount of stomach acid made by glands in ... Proton pump inhibitors are used to: Relieve symptoms of acid reflux, or gastroesophageal reflux disease (GERD). This is a ...

  6. [Inhibitors of xanthine oxidoreductase].

    PubMed

    Okamoto, Ken

    2008-04-01

    Inhibitors of xanthine oxidoreductase decrease production of uric acid, thus they act as hypouricemic drugs. Allopurinol, a prototypical xanthine oxidoreductase inhibitor, has been widely prescribed for treatment of gout and hyperuricemia. However, severe side effects of allopurinol may occur in patients with renal insufficiency. Recently, novel nonpurine selective inhibitors of xanthine oxidoreductase have been developed as potential alternatives to allopurinol. They have different inhibition mechanisms, utilizing the enzyme structure and the reaction mechanism. Such variation of the inhibition mechanism affects/in vivo/hypouricemic effects of the inhibitors. PMID:18409526

  7. The role of plasminogen activator inhibitor-1 in gastric mucosal protection

    PubMed Central

    Kenny, Susan; Steele, Islay; Lyons, Suzanne; Moore, Andrew R.; Murugesan, Senthil V.; Tiszlavicz, Laszlo; Dimaline, Rod; Pritchard, D. Mark; Varro, Andrea

    2013-01-01

    Gastric mucosal health is maintained in response to potentially damaging luminal factors. Aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) disrupt protective mechanisms leading to bleeding and ulceration. The plasminogen activator system has been implicated in fibrinolysis following gastric ulceration, and an inhibitor of this system, plasminogen activator inhibitor (PAI)-1, is expressed in gastric epithelial cells. In Helicobacter pylori-negative patients with normal gastric histology taking aspirin or NSAIDs, we found elevated gastric PAI-1 mRNA abundance compared with controls; the increase in patients on aspirin was independent of whether they were also taking proton pump inhibitors. In the same patients, aspirin tended to lower urokinase plasminogen activator mRNA. Immunohistochemistry indicated PAI-1 localization to epithelial cells. In a model system using MKN45 or AGS-GR cells transfected with a PAI-1 promoter-luciferase reporter construct, we found no evidence for upregulation of PAI-1 expression by indomethacin, and, in fact, cyclooxygenase products such as PGE2 and PGI2 weakly stimulated expression. Increased gastric PAI-1 mRNA was also found in mice following gavage with ethanol or indomethacin, but plasma PAI-1 was unaffected. In PAI-1−/− mice, gastric hemorrhagic lesions in response to ethanol or indomethacin were increased compared with C57BL/6 mice. In contrast, in PAI-1-H/Kβ mice in which PAI-1 is overexpressed in parietal cells, there were decreased lesions in response to ethanol and indomethacin. Thus, PAI-1 expression is increased in gastric epithelial cells in response to mucosal irritants such as aspirin and NSAIDs probably via an indirect mechanism, and PAI-1 acts as a local autoregulator to minimize mucosal damage. PMID:23494120

  8. Altered plasma fibrin clot properties in essential thrombocythemia.

    PubMed

    Małecki, Rafał; Gacka, Małgorzata; Kuliszkiewicz-Janus, Małgorzata; Jakobsche-Policht, Urszula; Kwiatkowski, Jacek; Adamiec, Rajmund; Undas, Anetta

    2016-03-01

    Patients with increased thromboembolic risk tend to form denser fibrin clots which are relatively resistant to lysis. We sought to investigate whether essential thrombocythemia (ET) is associated with altered fibrin clot properties in plasma. Ex vivo plasma fibrin clot permeability coefficient (Ks), turbidimetry and clot lysis time (CLT) were measured in 43 consecutive patients with ET (platelet count from 245 to 991 × 10(3)/µL) and 50 control subjects matched for age, sex and comorbidities. Fibrinolysis proteins and inhibitors together with platelet activation markers were determined. Reduced Ks (-38%, p < 0.0001) and prolonged CLT (+34%, p < 0.0001) were observed in ET. The differences remained significant after adjustment for fibrinogen and platelet count. ET was associated with a slightly shorter lag phase (-5%, p = 0.01) and higher maximum absorbency of the turbidimetric curve (+6%, p < 0.001). The ET patients had higher plasma P-selectin by 193% (p < 0.00001) and platelet factor 4 (PF4) by 173% (p < 0.00001), with higher P-selectin observed in 19 (44%) patients with JAK-2 gene V617F mutation. Higher t-PA (+20%, p < 0.001), 23% higher plasminogen activator inhibitor-1, PAI-1 (+23%, p < 0.01) and unaltered thrombin-activatable fibrinolysis inhibitor, plasminogen and α2-antiplasmin activity were found in the ET group. Ks inversely correlated with fibrinogen, PF4 and C-reactive protein. CLT positively correlated only with PAI-1. Patients with ET display prothrombotic plasma fibrin clot phenotype including impaired fibrinolysis, which represents a new prothrombotic mechanism in this disease. PMID:25989112

  9. Novel corrosion inhibitor technology

    SciTech Connect

    Van de Ven, P.; Fritz, P.; Pellet, R.

    1999-11-01

    A novel, patented corrosion inhibitor technology has been identified for use in heat transfer applications such as automotive and heavy-duty coolant. The new technology is based on a low-toxic, virtually depletion-free carboxylic acid corrosion inhibitor package that performs equally well in mono ethylene glycol and in less toxic propylene glycol coolants. An aqueous inhibitor concentrate is available to provide corrosion protection where freezing protection is not an issue. In the present paper, this inhibitor package is evaluated in the different base fluids: mono ethylene glycol, mono propylene glycol and water. Results are obtained in both standardized and specific corrosion tests as well as in selected field trials. These results indicate that the inhibitor package remains effective and retains the benefits previously identified in automotive engine coolant applications: excellent corrosion protection under localized conditions, general corrosion conditions as well as at high temperature.

  10. Plasminogen Activator Inhibitor Type 1 Interacts with α3 Subunit of Proteasome and Modulates Its Activity*

    PubMed Central

    Boncela, Joanna; Przygodzka, Patrycja; Papiewska-Pajak, Izabela; Wyroba, Elzbieta; Osinska, Magdalena; Cierniewski, Czeslaw S.

    2011-01-01

    Plasminogen activator inhibitor type-1 (PAI-1), a multifunctional protein, is an important physiological regulator of fibrinolysis, extracellular matrix homeostasis, and cell motility. Recent observations show that PAI-1 may also be implicated in maintaining integrity of cells, especially with respect to cellular proliferation or apoptosis. In the present study we provide evidence that PAI-1 interacts with proteasome and affects its activity. First, by using the yeast two-hybrid system, we found that the α3 subunit of proteasome directly interacts with PAI-1. Then, to ensure that the PAI-1-proteasome complex is formed in vivo, both proteins were coimmunoprecipitated from endothelial cells and identified with specific antibodies. The specificity of this interaction was evidenced after transfection of HeLa cells with pCMV-PAI-1 and coimmunoprecipitation of both proteins with anti-PAI-1 antibodies. Subsequently, cellular distribution of the PAI-1-proteasome complexes was established by immunogold staining and electron microscopy analyses. Both proteins appeared in a diffuse cytosolic pattern but also could be found in a dense perinuclear and nuclear location. Furthermore, PAI-1 induced formation of aggresomes freely located in endothelial cytoplasm. Increased PAI-1 expression abrogated degradation of degron analyzed after cotransfection of HeLa cells with pCMV-PAI-1 and pd2EGFP-N1 and prevented degradation of p53 as well as IκBα, as evidenced both by confocal microscopy and Western immunoblotting. PMID:21135093

  11. Screening of telomerase inhibitors.

    PubMed

    Kleideiter, Elke; Piotrowska, Kamilla; Klotz, Ulrich

    2007-01-01

    Shortening of telomeres prevents cells from uncontrolled proliferation. Progressive telomere shortening occurs at each cell division until a critical telomeric length is reached. Telomerase expression is switched off after embryonic differentiation in most normal cells, but it is expressed in a very high percentage of tumors of different origin. Thus, telomerase is regarded as the best tumor marker and a promising novel molecular target for cancer treatment. Therefore, different strategies to inhibit telomerase have been developed. However, systematic screening of telomerase inhibitors has not been performed to compare their therapeutic potential. We propose a suitable strategy for estimation of the therapeutic potential of telomerase inhibitors, which is based on a systematic screening of different inhibitors in the same cell system. From the long list of compounds discussed in the literature, we have selected four telomerase inhibitors of different structure and mode of action: BRACO19 (G-quadruplex-interactive compound), BIBR1532 (non-nucleosidic reverse transcriptase inhibitor), 2'-O-methyl RNA, and peptide nucleic acids (PNAs; hTR antisense oligonucleotides). To determine minimal effective concentrations for telomerase inhibition, telomerase activity was measured using the cell-free telomerase repeat amplification protocol (TRAP) assay. We also tested inhibitors in long-term cell-culture experiments by exposing A-549 cells to non-cytotoxic concentrations of inhibitors for a period of 99 days. Subsequently, telomerase activity of A-549 cells was investigated using the TRAP assay, and telomere length of samples was assessed by telomere restriction fragment (TRF) Southern blot analysis. PMID:18369824

  12. Synthetic inhibitors of elastase.

    PubMed

    Edwards, P D; Bernstein, P R

    1994-03-01

    For more than two decades investigators around the world, in both academic and industrial institutions, have been developing inhibitors of human neutrophil elastase. A number of very elegant and insightful strategies have been reported. In the case of reversible peptidic inhibitors, this has resulted in the identification of some extremely potent compounds with dissociation constants in the 10(-11) M range. This is quite an accomplishment considering that these low molecular-weight inhibitors are only tri- and tetrapeptides. In the case of the heterocyclic-based inhibitors, the challenge of balancing the heterocycle's inherent reactivity and aqueous stability with the stability of the enzyme-inhibitor adduct has been meet by either using a latent, reactive functionality which is only activated within the enzyme, or by incorporating features which selectively obstruct deacylation but have little effect on the enzyme acylation step. The underlying goal of this research has been the identification of agents to treat diseases associated with HNE. Several animal models have been developed for evaluating the in vivo activity of elastase inhibitors, and compounds have been shown to be effective in all of these models by the intravenous, intratrachael or oral routes of administration. However, only a very small percentage of compounds have possessed all the necessary properties, including lack of toxicity, for progression into the clinic. The peptidyl TFMK ICI 200,880 (25-12) has many of the desired characteristics of a drug to treat the diseases associated with HNE: chemical stability, in vitro and in vivo activity, a long duration of action, and adequate metabolic stability. Currently ICI 200,880 is the only low molecular-weight HNE inhibitor known to be undergoing clinical trials, and may be the compound which finally demonstrates the clinical utility of a synthetic HNE inhibitor. PMID:8189835

  13. [STAT3 inhibitor].

    PubMed

    Kitamura, Toshio

    2011-01-01

    Clinical efficacies of various molecular-targeted drugs have been recently demonstrated. Most of these drugs are kinase inhibitors. A most successful drug Glivec is an inhibitor of Bcr-Abl fusion kinase, derived from a well-known causative chromosome translocation of chronic myeloid leukemia(CML). Although other kinase inhibitors have also proved to be useful in the therapy of malignant diseases including an ALK inhibitor for lung carcinomas, a general problem of kinase inhibitors is their lowspecificities. Therefore, the complication of these drugs must be overcome. Recently, trials to develop moleculartargeted therapy whose targets are molecules other than kinases have also been promising. Among molecular targets, STAT3 has attracted a great deal of researchers' attention because it is constitutively activated in most malignant tumors and plays important roles in carcinogenesis. This article summarizes the current situation and problems to be solved with STAT3 inhibitors as well as our recent findings on the molecular mechanisms of STAT3 activation. PMID:21368456

  14. The Occurrence of Thrombosis in Inflammatory Bowel Disease Is Reflected in the Clot Lysis Profile

    PubMed Central

    Bollen, Lize; Vande Casteele, Niels; Peeters, Miet; Van Assche, Gert; Ferrante, Marc; Van Moerkercke, Wouter; Declerck, Paul; Vermeire, Séverine

    2015-01-01

    Background: The occurrence of thromboembolic events (TE) is an important extraintestinal manifestation in patients with inflammatory bowel disease (IBD). The aim of this study was to compare fibrinolysis and clot lysis parameters between (1) patients with IBD and healthy controls and (2) patients with IBD with TE (IBD + TE) and without TE (IBD − TE). Methods: One hundred thirteen healthy controls and 202 patients with IBD, of which 84 patients with IBD + TE and 118 patients with IBD − TE, were included in this case–control study. Three clot lysis parameters (area under the curve, 50% clot lysis time, and amplitude) were determined using a clot lysis assay. Plasminogen activator inhibitor 1 (PAI-1) and thrombin activatable fibrinolysis inhibitor concentrations were determined by enzyme-linked immunosorbent assay. Results: PAI-1 antigen, active PAI-1, and intact thrombin activatable fibrinolysis inhibitor concentrations, as well as 50% clot lysis time and area under the curve, were significantly associated with the presence of IBD (all P < 0.05). The median time between TE and plasma collection was 5.0 (1.8–11.0) years. Comparing IBD + TE versus IBD − TE, active to total PAI-1 ratio (0.36 [0.24–0.61] versus 0.24 [0.13–0.40]), area under the curve (31 [24–49] versus 22 [13-31]), 50% clot lysis time (110 [64–132] versus 95 [70–126] minutes), and amplitude (0.295 [0.222–0.436] versus 0.241 [0.168–0.308]) were significantly higher in IBD + TE (all P <0.05) and remained higher after adjustment for age, gender, C-reactive protein, type of disease, presence of comorbidities, and disease activity. Conclusions: Patients with IBD have an altered clot lysis profile compared with healthy controls. Clot lysis parameters differ significantly between patients with IBD with and without a history of TE and should be included in the risk assessment. PMID:26313696

  15. Aromatase and its inhibitors.

    PubMed

    Brodie, A; Lu, Q; Long, B

    1999-01-01

    Inhibitors of aromatase (estrogen synthetase) have been developed as treatment for postmenopausal breast cancer. Both steroidal substrate analogs, type I inhibitors, which inactivate the enzyme and non-steroidal competitive reversible, type II inhibitors, are now available. 4-hydroxyandrostenedione (4-OHA), the first selective aromatase inhibitor, has been shown to reduce serum estrogen concentrations and cause complete and partial responses in approximately 25% of patients with hormone responsive disease who have relapsed from previous endocrine treatment. Letrozole (CGS 20, 269) and anastrozole (ZN 1033) have been recently approved for treatment. Both suppress serum estrogen levels to the limit of assay detection. Letrozole has been shown to be significantly superior to megace in overall response rates and time to treatment failure, whereas anastrozole was found to improve survival in comparison to megace. Both were better tolerated than the latter. The potential of aromatase within the breast as a significant source of estrogen mediating tumor proliferation and which might determine the outcome of inhibitor treatment was explored. Using immunocytochemistry and in situ hybridization, aromatase and mRNAarom was detected mainly in the epithelial cells of the terminal ductal lobular units (TDLU) of the normal breast and also in breast tumor epithelial cells as well as some stromal cells. Increase in proliferation, measured by increased thymidine incorporation into DNA and by PCNA immunostaining in response to testosterone was observed in histocultures of breast cancer samples. This effect could be inhibited by 4-OHA and implies that intratumoral aromatase has functional significance. An intratumoral aromatase model in the ovariectomized nude mouse was developed which simulated the hormone responsive postmenopausal breast cancer patient. This model also allows evaluation of the efficacy of aromatase inhibitors and antiestrogens in tumors of estrogen receptor positive

  16. Characterization of a Kunitz-type protease inhibitor (MjKuPI) reveals the involvement of MjKuPI positive hemocytes in the immune responses of kuruma shrimp Marsupenaeus japonicus.

    PubMed

    Mai, Hung Nam; Nguyen, Ha Thi Nhu; Koiwai, Keiichiro; Kondo, Hidehiro; Hirono, Ikuo

    2016-10-01

    Serine proteases and their inhibitors play vital roles in biological processes. Serine protease inhibitors, including Kunitz-type protease inhibitors play important roles not only in physiological process (i.e. blood clotting and fibrinolysis) but also in immune responses. In this study, we characterized a Kunitz-type protease inhibitor, designated MjKuPI, from kuruma shrimp Marsupenaeus japonicus. An expression profile showed that MjKuPI was mainly expressed in hemocytes. Immunostaining revealed that some hemocytes expressed MjKuPI (MjKuPI(+) hemocytes) and others did not (MjKuPI(-) hemocytes). Injection of shrimp with Vibrio penaeicida and white spot syndrome virus (WSSV) upregulated the mRNA level of MjKuPI, and a flow cytometry analysis revealed that the proportion of MjKuPI(+) hemocytes increased significantly 24 h after injection. Together, these results suggest that MjKuPI and MjKuPI(+) hemocytes have a role in the innate immune system of kuruma shrimp. PMID:27255219

  17. Small-molecule caspase inhibitors

    NASA Astrophysics Data System (ADS)

    Zhenodarova, S. M.

    2010-02-01

    The review considers low-molecular weight inhibitors of caspases, cysteine proteases being key contributors to apoptosis (programmed cell death). The inhibitors with aspartic acid residues or various heterocyclic systems (both synthetic and natural) are covered. Their possible mechanisms of action are discussed. Data on inhibitor structure-activity relationship studies are systematically surveyed. The interactions of the non-peptide fragments of an inhibitor with the enzymes are examined. Examples of the use of some inhibitors for apoptosis suppression are provided.

  18. In vitro clot lysis as a potential indicator of thrombus resistance to fibrinolysis--study in healthy subjects and correlation with blood fibrinolytic parameters.

    PubMed

    Colucci, M; Scopece, S; Gelato, A V; Dimonte, D; Semeraro, N

    1997-04-01

    Using an in vitro model of clot lysis, the individual response to a pharmacological concentration of recombinant tissue plasminogen activator (rt-PA) and the influence on this response of the physiological variations of blood parameters known to interfere with the fibrinolytic/thrombolytic process were investigated in 103 healthy donors. 125I-fibrin labelled blood clots were submersed in autologous plasma, supplemented with 500 ng/ml of rt-PA or solvent, and the degree of lysis was determined after 3 h of incubation at 37 degrees C. Baseline plasma levels of t-PA, plasminogen activator inhibitor 1 (PAI-1), plasminogen, alpha 2-antiplasmin, fibrinogen, lipoprotein (a), thrombomodulin and von Willebrand factor as well as platelet and leukocyte count and clot retraction were also determined in each donor. rt-PA-induced clot lysis varied over a wide range (28-75%) and was significantly related to endogenous t-PA, PAI-1, plasminogen (p < 0.001) and age (p < 0.01). Multivariate analysis indicated that both PAI-1 antigen and plasminogen independently predicted low response to rt-PA. Surprisingly, however, not only PAI-1 but also plasminogen was negatively correlated with rt-PA-induced clot lysis. The observation that neutralization of PAI-1 by specific antibodies, both in plasma and within the clot, did not potentiate clot lysis indicates that the inhibitor, including the platelet-derived form, is insufficient to attenuate the thrombolytic activity of a pharmacological concentration of rt-PA and that its elevation, similarly to the elevation of plasminogen, is not the cause of clot resistance but rather a coincident finding. It is concluded that the in vitro response of blood clots to rt-PA is poorly influenced by the physiological variations of the examined parameters and that factors other than those evaluated in this study interfere with clot dissolution by rt-PA. In vitro clot lysis test might help to identify patients who may be resistant to thrombolytic therapy

  19. SGLT2 inhibitors.

    PubMed

    Dardi, I; Kouvatsos, T; Jabbour, S A

    2016-02-01

    Diabetes mellitus is a serious health issue and an economic burden, rising in epidemic proportions over the last few decades worldwide. Although several treatment options are available, only half of the global diabetic population achieves the recommended or individualized glycemic targets. Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new class of antidiabetic agents with a novel insulin-independent action. SGLT2 is a transporter found in the proximal renal tubules, responsible for the reabsorption of most of the glucose filtered by the kidney. Inhibition of SGLT2 lowers the blood glucose level by promoting the urinary excretion of excess glucose. Due to their insulin-independent action, SGLT2 inhibitors can be used with any degree of beta-cell dysfunction or insulin resistance, related to a very low risk of hypoglycemia. In addition to improving glycemic control, SGLT2 inhibitors have been associated with a reduction in weight and blood pressure when used as monotherapy or in combination with other antidiabetic agents in patients with type 2 diabetes mellitus (T2DM). Treatment with SGLT2 inhibitors is usually well tolerated; however, they have been associated with an increased incidence of urinary tract and genital infections, although these infections are usually mild and easy to treat. SGLT2 inhibitors are a promising new option in the armamentarium of drugs for patients with T2DM. PMID:26362302

  20. Cholinesterase inhibitors from botanicals.

    PubMed

    Ahmed, Faiyaz; Ghalib, Raza Murad; Sasikala, P; Ahmed, K K Mueen

    2013-07-01

    Alzheimer's disease (AD) is a progressive neurodegenerative disease, wherein a progressive loss of cholinergic synapses occurs in hippocampus and neocortex. Decreased concentration of the neurotransmitter, acetylcholine (ACh), appears to be critical element in the development of dementia, and the most appropriate therapeutic approach to treat AD and other form of dementia is to restore acetylcholine levels by inhibiting both major form of cholinesterase: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Consequently, researches have focused their attention towards finding cholinesterase inhibitors from natural products. A large number of such inhibitors have been isolated from medicinal plants. This review presents a comprehensive account of the advances in field of cholinesterase inhibitor phytoconstituents. The structures of some important phytoconstituents (collected through www.Chemspider.com) are also presented and the scope for future research is discussed. PMID:24347920

  1. Cholinesterase inhibitors from botanicals

    PubMed Central

    Ahmed, Faiyaz; Ghalib, Raza Murad; Sasikala, P.; Ahmed, K. K. Mueen

    2013-01-01

    Alzheimer's disease (AD) is a progressive neurodegenerative disease, wherein a progressive loss of cholinergic synapses occurs in hippocampus and neocortex. Decreased concentration of the neurotransmitter, acetylcholine (ACh), appears to be critical element in the development of dementia, and the most appropriate therapeutic approach to treat AD and other form of dementia is to restore acetylcholine levels by inhibiting both major form of cholinesterase: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Consequently, researches have focused their attention towards finding cholinesterase inhibitors from natural products. A large number of such inhibitors have been isolated from medicinal plants. This review presents a comprehensive account of the advances in field of cholinesterase inhibitor phytoconstituents. The structures of some important phytoconstituents (collected through www.Chemspider.com) are also presented and the scope for future research is discussed. PMID:24347920

  2. Testosterone and phosphodiesterase type-5 inhibitors: new strategy for preventing endothelial damage in internal and sexual medicine?

    PubMed Central

    Aversa, Antonio; Bruzziches, Roberto; Francomano, Davide; Natali, Marco; Lenzi, Andrea

    2009-01-01

    Normal vascular endothelium is essential for the synthesis and release of substances affecting vascular tone (e.g. nitric oxide; NO), cell adhesion (e.g. endothelins, interleukins), and the homeostasis of clotting and fibrinolysis (e.g. plasminogen inhibitors, von Willebrand factor). The degeneration of endothelial integrity promotes adverse events (AEs) leading to increased atherogenesis and to the development of vascular systemic and penile end-organ disease. Testosterone (T) is an important player in the regulation of vascular tone through non-genomic actions exerted via blockade of extracellular-calcium entry or activation of potassium channels; also, adequate T concentrations are paramount for the regulation of phosphodiesterase type-5 (PDE5) expression and finally, for the actions exerted by hydrogen sulphide, a gas involved in the alternative pathway controlling vasodilator responses in penile tissue. It is known that an age-related decline of serum T is reported in approximately 20 to 30% of men whereas T deficiency is reported in up to 50% of men with metabolic syndrome or diabetes. A number of laboratory and human studies have shown the combination of T and other treatments for erectile dysfunction (ED), such as PDE5 inhibitors, to be more beneficial in patients with ED and hypogonadism, who fail monotherapy for sexual disturbances. The aim of this review is to show evidence on the role of T and PDE5 inhibitors, alone or in combination, as potential boosters of endothelial function in internal medicine diseases associated with reduced T or NO bioavailability, i.e. metabolic syndrome, obesity, diabetes, coronary artery disease, hyperhomocysteinemia, that share common risk factors with ED. Furthermore, the possibility of such a strategy to prevent endothelial dysfunction in men at increased cardiovascular risk is discussed. PMID:21789066

  3. Protein protease inhibitors in insects and comparison with mammalian inhibitors.

    PubMed

    Eguchi, M

    1993-01-01

    1. Studies on insect protein protease inhibitors are summarized. Biochemical, genetic and physiological investigations of the silkworm are performed. 2. In addition, the properties and characteristics of fungal protease inhibitors from the silkworm (Bombyx mori) are described and their importance as defensive functions is emphasized. 3. This review also concerns comparative and evolutionary studies of protease inhibitors from various sources. 4. The biological significance of inhibitors is discussed in view of the extensive experimental results. PMID:8365101

  4. Sunflower trypsin inhibitor-1.

    PubMed

    Korsinczky, Michael L J; Schirra, Horst Joachim; Craik, David J

    2004-10-01

    SFTI-1 is a bicyclic 14 amino acid peptide that was originally isolated from the seeds of the sunflower Helianthus annuus. It is a potent inhibitor of trypsin, with a sub-nanomolar K(i) value and is homologous to the active site region of the well-known family of serine protease inhibitors known as the Bowman-Birk trypsin inhibitors. It has a cyclic backbone that is cross-braced by a single disulfide bridge and a network of hydrogen bonds that result in a well-defined structure. SFTI-1 is amenable to chemical synthesis, allowing for the creation of synthetic variants. Alterations to the structure such as linearising the backbone or removing the disulfide bridge do not reduce the potency of SFTI-1 significantly, and minimising the peptide to as few as nine residues results in only a small decrease in reactivity. The creation of linear variants of SFTI-1 also provides a tool for investigating putative linear precursor peptides. The mechanism of biosynthesis of SFTI-1 is not yet known but it seems likely that it is a gene-coded product that has arisen from a precursor protein that may be evolutionarily related to classic Bowman-Birk inhibitors. PMID:15544530

  5. Inhibitors of rhomboid proteases.

    PubMed

    Wolf, Eliane V; Verhelst, Steven H L

    2016-03-01

    Rhomboid proteases form one of the most widespread families of intramembrane proteases. They utilize a catalytic serine-histidine dyad located several Å below the surface of the membrane for substrate hydrolysis. Multiple studies have implicated rhomboid proteases in biologically and medically relevant processes. Several assays have been developed that are able to monitor rhomboid activity. With the aid of these assays, different types of inhibitors have been found, all based on electrophiles that covalently react with the active site machinery. Although the currently available inhibitors have limited selectivity and moderate potency, they can function as research tools and as starting point for the development of activity-based probes, which are reagents that can specifically detect active rhomboid species. Structural studies on complexes of inhibitors with the Escherichia coli rhomboid GlpG have provided insight into how substrate recognition may occur. Future synthetic efforts, aided by high-throughput screening or structure-based design, may lead to more potent and selective inhibitors for this interesting family of proteases. PMID:26166068

  6. Lack of association between Ser413/Cys polymorphism of plasminogen activator inhibitor type 2 (PAI-2) and premature coronary atherosclerotic disease

    PubMed Central

    Saffari, Babak; Jooyan, Najmeh; Bahari, Marzieh; Senemar, Sara; Yavarian, Majid

    2012-01-01

    Plasminogen activator inhibitor type-2 (PAI-2) is a serine protease inhibitor of the fibrinolytic system produced predominantly by the macrophages and monocytes. It has been demonstrated that fibrinolysis regulation has a great importance in the pathogenesis of atherosclerotic plaques. Thus in the current investigation, we sought to determine whether Ser413/Cys polymorphism (rs6104) of PAI-2 gene could be associated with atherosclerosis and cardiovascular risk factors. Ser413/Cys polymorphism was determined by PCR-RFLP technique using Mwo I restriction enzyme for 184 men under 50 years of age and 216 women less than 55 years of age who underwent diagnostic coronary angiography. Data on the history of familial myocardial infarction or other heart diseases, hypertension, and smoking habit were collected by a simple questionnaire. Fasting levels of blood sugar, triglycerides, total cholesterol, low-density lipoprotein and high-density lipoprotein cholesterol levels were also measured by enzymatic methods. Frequencies of the Ser413 and Cys413 alleles were 0.760 and 0.240 in the whole population, respectively. The PAI-2 gene variant analyzed was not significantly associated with either the prevalence of premature CAD or the classical risk factors of CAD development such as diabetes, serum cholesterol, triglycerides, low-density lipoprotein and high-density lipoprotein cholesterol, body mass index, hypertension, familial history of heart dysfunction or smoking.

  7. Endogenous plasma activated protein C levels and the effect of enoxaparin and drotrecogin alfa (activated) on markers of coagulation activation and fibrinolysis in pulmonary embolism

    PubMed Central

    2011-01-01

    Introduction There are no published data on the status of endogenous activated protein C (APC) in pulmonary embolism (PE), and no data on the effect of drotrecogin alfa (activated) (DAA) given in addition to therapeutic dose enoxaparin. Methods In this double-blind clinical trial, 47 patients with computed tomography (CT)-confirmed acute submassive PE treated with 1 mg/kg body weight of enoxaparin twice daily were randomized to groups receiving a 12-hour intravenous infusion of 6, 12, 18, or 24 μg/kg/hour of DAA or a placebo. Blood samples were drawn before starting DAA infusion, after 4, 8 and 12 hours (at the end of the infusion period), and on treatment days 2, 3, 4, 5 and 6. Results Initial endogenous plasma activated protein C (APC) levels were 0.36 ± 0.48 ng/ml (<0.10 to 1.72 ng/ml) and remained in the same range in the placebo group. APC levels in patients treated with DAA were 13.67 ± 3.57 ng/ml, 32.71 ± 8.76 ng/ml, 36.13 ± 7.60 ng/ml, and 51.79 ± 15.84 ng/ml in patients treated with 6, 12, 18, and 24 μg/kg/hour DAA, respectively. In patients with a D-dimer level >4 mg/L indicating a high level of acute fibrin formation and dissolution, DAA infusion resulted in a more rapid drop in soluble fibrin, D-dimer, and fibrinogen/fibrin degradation products (FDP) levels, compared to enoxaparin alone. There was a parallel decline of soluble fibrin, D-dimer, FDP, and plasmin-plasmin inhibitor complex (PPIC) in response to treatment with enoxaparin ± DAA, with no evidence of a systemic profibrinolytic effect of the treatment. Conclusions In patients with acute submassive PE endogenous APC levels are low. DAA infusion enhances the inhibition of fibrin formation. Trial registration ClinicalTrials.gov: NCT00191724 PMID:21241489

  8. Recent advances for FLAP inhibitors.

    PubMed

    Pettersen, Daniel; Davidsson, Öjvind; Whatling, Carl

    2015-07-01

    A number of FLAP inhibitors have been progressed to clinical trials for respiratory and other inflammatory indications but so far no drug has reached the market. With this Digest we assess the opportunity to develop FLAP inhibitors for indications beyond respiratory disease, and in particular for atherosclerotic cardiovascular disease. We also show how recently disclosed FLAP inhibitors have structurally evolved from the first generation FLAP inhibitors paving the way for new compound classes. PMID:26004579

  9. Broad-Band Activatable White-Opsin

    PubMed Central

    Batabyal, Subrata; Cervenka, Gregory; Ha, Ji Hee; Kim, Young-tae; Mohanty, Samarendra

    2015-01-01

    Currently, the use of optogenetic sensitization of retinal cells combined with activation/inhibition has the potential to be an alternative to retinal implants that would require electrodes inside every single neuron for high visual resolution. However, clinical translation of optogenetic activation for restoration of vision suffers from the drawback that the narrow spectral sensitivity of an opsin requires active stimulation by a blue laser or a light emitting diode with much higher intensities than ambient light. In order to allow an ambient light-based stimulation paradigm, we report the development of a ‘white-opsin’ that has broad spectral excitability in the visible spectrum. The cells sensitized with white-opsin showed excitability at an order of magnitude higher with white light compared to using only narrow-band light components. Further, cells sensitized with white-opsin produced a photocurrent that was five times higher than Channelrhodopsin-2 under similar photo-excitation conditions. The use of fast white-opsin may allow opsin-sensitized neurons in a degenerated retina to exhibit a higher sensitivity to ambient white light. This property, therefore, significantly lowers the activation threshold in contrast to conventional approaches that use intense narrow-band opsins and light to activate cellular stimulation. PMID:26360377

  10. Alpha glucosidase inhibitors.

    PubMed

    Kalra, Sanjay

    2014-04-01

    Alpha glucosidase inhibitors (AGIs) are a unique class of anti-diabetic drugs. Derived from bacteria, these oral drugs are enzyme inhibitors which do not have a pancreato -centred mechanism of action. Working to delay carbohydrate absorption in the gastrointestinal tract, they control postprandial hyperglycaemia and provide unquestioned cardiovascular benefit. Specially suited for a traditional Pakistani carbohydrate-rich diet, AGIs have been termed the 'untapped diamonds' of diabetology. The use of these oral antidiabetic drugs (OADs) that target pathophysiology in the early stages of type 2 diabetes, notably to reduce postprandial hyperglycaemia and hyperinsulinaemia will inevitably increase with time. This review describes the history of their development, mechanism of action, basic and clinical pharmacology, and suggests practical, evidence-based guidance for their optimal use. PMID:24864650

  11. [JAK2 inhibitors].

    PubMed

    Hernández Boluda, Juan Carlos; Gómez, Montse; Pérez, Ariadna

    2016-07-15

    Pharmacological inhibition of the kinase activity of JAK proteins can interfere with the signaling of immunomodulatory cytokines and block the constitutive activation of the JAK-STAT pathway that characterizes certain malignancies, including chronic myeloproliferative neoplasms. JAK inhibitors may, therefore, be useful to treat malignancies as well as inflammatory or immune disorders. Currently, the most significant advances have been made in the treatment of myelofibrosis, where these drugs may lead to a remarkable improvement in the control of hyperproliferative manifestations. However, available data suggest that this treatment is not curative of myelofibrosis. In general, JAK2 inhibition induces cytopaenias, with this being considered a class side-effect. By contrast, the extrahaematologic toxicity profile varies significantly among the different JAK inhibitors. At present, there are several clinical trials evaluating the combination of ruxolitinib with other drugs, in order to improve its therapeutic activity as well as reducing haematologic toxicity. PMID:27033437

  12. PARP inhibitors and more.

    PubMed

    Bose, Chinmoy K; Basu, Nirban

    2015-01-01

    Polyadenosine diphosphate (ADP) ribose polymerase (PARP) lends a panoramic view to the inner mystery of protection of integrity of deoxyribonucleic acid (DNA) in a cell genome. They are a balancing part of an even more dynamic equilibrium of normalcy against daily assaults. PARP finds its companion candidates in other tumor suppressors, with the most prominent and glaring one being breast cancer (BRCA) 1 and 2. The strength of both is split by PARP inhibitors, inculcating the synthetic lethality of tumor cell, which is now in the market for ovarian cancer treatment. There are many reasons for the resistance of such inhibitors, which are now becoming clinically important. These are seen along with other damage repair approaches. PMID:26097394

  13. PARP inhibitors and more

    PubMed Central

    Bose, Chinmoy K.; Basu, Nirban

    2015-01-01

    Polyadenosine diphosphate (ADP) ribose polymerase (PARP) lends a panoramic view to the inner mystery of protection of integrity of deoxyribonucleic acid (DNA) in a cell genome. They are a balancing part of an even more dynamic equilibrium of normalcy against daily assaults. PARP finds its companion candidates in other tumor suppressors, with the most prominent and glaring one being breast cancer (BRCA) 1 and 2. The strength of both is split by PARP inhibitors, inculcating the synthetic lethality of tumor cell, which is now in the market for ovarian cancer treatment. There are many reasons for the resistance of such inhibitors, which are now becoming clinically important. These are seen along with other damage repair approaches. PMID:26097394

  14. Benzoylurea Chitin Synthesis Inhibitors.

    PubMed

    Sun, Ranfeng; Liu, Chunjuan; Zhang, Hao; Wang, Qingmin

    2015-08-12

    Benzoylurea chitin synthesis inhibitors are widely used in integrated pest management (IPM) and insecticide resistance management (IRM) programs due to their low toxicity to mammals and predatory insects. In the past decades, a large number of benzoylurea derivatives have been synthesized, and 15 benzoylurea chitin synthesis inhibitors have been commercialized. This review focuses on the history of commercial benzolyphenylureas (BPUs), synthetic methods, structure-activity relationships (SAR), action mechanism research, environmental behaviors, and ecotoxicology. Furthermore, their disadvantages of high risk to aquatic invertebrates and crustaceans are pointed out. Finally, we propose that the para-substituents at anilide of benzoylphenylureas should be the functional groups, and bipartite model BPU analogues are discussed in an attempt to provide new insight for future development of BPUs. PMID:26168369

  15. Mineralization by Inhibitor Exclusion

    PubMed Central

    Price, Paul A.; Toroian, Damon; Lim, Joo Eun

    2009-01-01

    One of our goals is to understand the mechanisms that deposit mineral within collagen fibrils, and as a first step we recently determined the size exclusion characteristics of the fibril. This study revealed that apatite crystals up to 12 unit cells in size can access the water within the fibril, whereas molecules larger than a 40-kDa protein are excluded. Based on these observations, we proposed a novel mechanism for fibril mineralization: that macromolecular inhibitors of apatite growth favor fibril mineralization by selectively inhibiting crystal growth in the solution outside of the fibril. To test this mechanism, we developed a system in which crystal formation is driven by homogeneous nucleation at high calcium phosphate concentration and the only macromolecule in solution is fetuin, a 48-kDa inhibitor of apatite growth. Our experiments with this system demonstrated that fetuin determines the location of mineral growth; in the presence of fetuin mineral grows exclusively within the fibril, whereas in its absence mineral grows in solution outside the fibril. Additional experiments showed that fetuin is also able to localize calcification to the interior of synthetic matrices that have size exclusion characteristics similar to those of collagen and that it does so by selectively inhibiting mineral growth outside of these matrices. We termed this new calcification mechanism “mineralization by inhibitor exclusion,” the selective mineralization of a matrix using a macromolecular inhibitor of mineral growth that is excluded from that matrix. Future studies will be needed to evaluate the possible role of this mechanism in bone mineralization. PMID:19414589

  16. Neutrophil Elastase Inhibitors

    PubMed Central

    Groutas, William C.; Dou, Dengfeng; Alliston, Kevin R.

    2011-01-01

    Introduction Chronic obstructive pulmonary disease (COPD) constitutes a worldwide health problem. There is currently an urgent and unmet need for the development of small molecule therapeutics capable of blocking and/or reversing the progression of the disorder. Recent studies have greatly illuminated our understanding of the multiple pathogenic processes associated with COPD. Of paramount importance is the key role played by proteases, oxidative stress, apoptosis, and inflammation. Insights gained from these studies have made possible the exploration of new therapeutic approaches. Areas covered An overview of major developments in COPD research with emphasis on low molecular weight neutrophil elastase inhibitors is described in this review. Expert opinion Great strides have been made toward our understanding of the biochemical and cellular events associated with COPD. However, our knowledge regarding the inter-relationships among the multiple pathogenic mechanisms and their mediators involved is till limited. The problem is further compounded by the unavailability of suitable validated biomarkers for assessing the efficacy of potential therapeutic interventions. The complexity of COPD suggests that effective therapeutic interventions may require the administration of more than one agent such as, for instance, an HNE or MMP-12 inhibitor with an anti-inflammatory agent such as a phosphodiesterase-4 inhibitor, or a dual function agent capable of disrupting the cycle of proteolysis, apoptosis, inflammation and oxidative stress PMID:21235378

  17. Development of scale inhibitors

    SciTech Connect

    Gill, J.S.

    1996-12-01

    During the last fifty years, scale inhibition has gone from an art to a science. Scale inhibition has changed from simple pH adjustment to the use of optimized dose of designer polymers from multiple monomers. The water-treatment industry faces many challenges due to the need to conserve water, availability of only low quality water, increasing environmental regulations of the water discharge, and concern for human safety when using acid. Natural materials such as starch, lignin, tannin, etc., have been replaced with hydrolytically stable organic phosphates and synthetic polymers. Most progress in scale inhibition has come from the use of synergistic mixtures and copolymerizing different functionalities to achieve specific goals. Development of scale inhibitors requires an understanding of the mechanism of crystal growth and its inhibition. This paper discusses the historic perspective of scale inhibition and the development of new inhibitors based on the understanding of the mechanism of crystal growth and the use of powerful tools like molecular modeling to visualize crystal-inhibitor interactions.

  18. Prognostic evaluation by clinical exercise test scores in patients treated with primary percutaneous coronary intervention or fibrinolysis for acute myocardial infarction (a Danish Trial in Acute Myocardial Infarction-2 Sub-Study).

    PubMed

    Valeur, Nana; Clemmensen, Peter; Grande, Peer; Saunamäki, Kari

    2007-10-01

    The prognostic accuracy of exercise testing after myocardial infarction is low, and different models have been proposed to enhance the predictive value for subsequent mortality. This study tested a simple score against 3 established scores. Patients with ST-elevation myocardial infarctions were randomized in the Danish Trial in Acute Myocardial Infarction-2 (DANAMI-2) to either primary percutaneous coronary intervention or fibrinolysis with predischarge exercise testing. Clinical and exercise test data were collected prospectively and were available for 1,115 patients. A simple score was derived, awarding 1 point for history or new signs of heart failure, 1 point for a left ventricular ejection fraction <40%, 1 point for age >65 years in men and age >70 years in women, and 1 point for exercise capacity <5 METs in men and exercise capacity <4 METs in women. This DANAMI score was compared with the Veterans Affairs Medical Center score, the Duke treadmill score, and the Gruppo Italiano per lo Studio Della Sopravvivenza nell'Infarto Miocardico-2 (GISSI-2) score in multivariate Cox models and receiver-operating characteristic plots. All scoring systems were predictive of adverse outcomes. The DANAMI score performed better, with greater chi-square values (142 vs 53 to 88 for the prediction of death). Areas under the receiver-operating characteristic curves were compared and were larger for the DANAMI score (C-statistic 0.79 vs 0.71 to 0.74 for the other tests regarding mortality). The DANAMI score stratified patients into a small high-risk group (8% of the population with 43% mortality in 6 years), an intermediate-risk group (13% with 16% mortality in 6 years), and a low-risk group (79% with 4% mortality in 6 years). In conclusion, a simple exercise test score composed of age, METs, heart failure, and a left ventricular ejection fraction <40% seems to outperform the Duke treadmill score, Veterans Affairs Medical Center score, and GISSI-2 score in risk stratifying

  19. Thymidylate synthase inhibitors.

    PubMed

    Danenberg, P V; Malli, H; Swenson, S

    1999-12-01

    Thymidylate synthase (TS) is a critical enzyme for DNA replication and cell growth because it is the only de novo source of thymine nucleotide precursors for DNA synthesis. TS is the primary target of 5-fluorouracil (5-FU), which has been used for cancer treatment for more than 40 years. However, dissatisfaction with the overall activity of 5-FU against the major cancers, and the recognition that TS still remains an attractive target for anticancer drugs because of its central position in the pathway of DNA synthesis, led to a search for new inhibitors of TS structurally analogous to 5,10-methylenetetrahydrofolate, the second substrate of TS. TS inhibitory antifolates developed to date that are in various stages of clinical evaluation are ZD 1694 and ZD9331 (Astra-Zeneca, London, UK), (Eli Lilly, Indianapolis, IN), LY231514 (BW1843U89 (Glaxo-Wellcome, Research Triangle Park, NC), and AG337 and AG331 (Agouron, La Jolla, CA). Although each of these compounds has TS as its major intracellular site of action, they differ in propensity for polyglutamylation and for transport by the reduced folate carrier. LY231514 also has secondary target enzymes. As a result, each compound is likely to have a different spectrum of antitumor activity and toxicity. This review will summarize the development and properties of this new class of TS inhibitors. PMID:10606255

  20. Synthesis of Lysine Methyltransferase Inhibitors

    NASA Astrophysics Data System (ADS)

    Ye, Tao; Hui, Chunngai

    2015-07-01

    Lysine methyltransferase which catalyze methylation of histone and nonhistone proteins, play a crucial role in diverse biological processes and has emerged as a promising target for the development of various human diseases, including cancer, inflammation, and psychiatric disorders. However, inhibiting Lysine methyltransferases selectively has presented many challenges to medicinal chemists. During the past decade, lysine methyltransferase inhibitors covering many different structural classes have been designed and developed. In this review, we describe the development of selective, small-molecule inhibitors of lysine methyltransferases with an emphasis on their discovery and chemical synthesis. We highlight the current state of lysine methyltransferase inhibitors and discuss future directions and opportunities for lysine methyltransferase inhibitor discovery.

  1. [Kinase inhibitors and their resistance].

    PubMed

    Togashi, Yosuke; Nishio, Kazuto

    2015-08-01

    Kinase cascades are involved in all stages of tumorigenesis through modulation of transformation and differentiation, cell-cycle progression, and motility. Advances in molecular targeted drug development allow the design and synthesis of inhibitors targeting cancer-associated signal transduction pathways. Potent selective inhibitors with low toxicity can benefit patients especially with several malignancies harboring an oncogenic driver addictive signal. This article evaluates information on solid tumor-related kinase signals and inhibitors, including receptor tyrosine kinase or serine/threonine kinase signals that lead to successful application in clinical settings. In addition, the resistant mechanisms to the inhibitors is summarized. PMID:26281685

  2. Repositioning of DHFR Inhibitors.

    PubMed

    Lele, Arundhati Chandrashekhar; Mishra, Deepak Amarnath; Kamil, Tengku Karmila; Bhakta, Sanjib; Degani, Mariam Sohel

    2016-01-01

    Development of new drugs is a time-consuming, hugely expensive and an uncertain endeavor. The pharmaceutical industry is looking for cost-effective alternatives with reduced risks of drug failure. Validated target machinery along with established inhibitors indicates usefulness in drug design, discovery and further development. Folate metabolism, found in both prokaryotes and eukaryotes, represents an essential druggable target for chemotherapy. Numerous enzymes in the cell replication cycle use folate either as a cofactor or as a substrate. DHFR, an enzyme of the folate biosynthesis pathway is an established chemotherapeutic target, initially explored for anti-cancer drug discovery. Diaminopteridines e.g. methotrexate and aminopterin, primarily used as anti-cancer agents, are folic acid analogues, first reported in late 1940's, used to produce temporary remission of acute leukaemia in children. However, due to the toxicity of these drugs, they could not be used for other therapeutic implications such as in the treatment of infectious diseases. Development of newer diaminopteridine derivatives has helped in repositioning their therapeutic usefulness. These analogues have now been proven as anti-parasitic, immuno-suppressants, anti-bacterial agents, to enlist a few therapeutic applications. Likewise, diaminopyrimidine, diaminoquinazoline and diaminodihydrotriazines are being explored for structural modifications by which they can be repurposed from their originally developed medicinal applicability and exploited for various other infectious disease conditions. In this review, we encompass the study of DHFR inhibitors potentially to be repurposed for different infectious disease case scenario and also highlight the novel anti-infective drug discovery benefits therein. PMID:26881719

  3. Osteocompatibility of Biofilm Inhibitors

    PubMed Central

    Rawson, Monica; Haggard, Warren; Jennings, Jessica A

    2014-01-01

    The demand for infection prevention therapies has led to the discovery of several biofilm inhibitors. These inhibiting signals are released by bacteria, fungi, or marine organisms to signal biofilm dispersal or disruption in Gram-positive, Gram-negative, and fungal microorganisms. The purpose of this study was to test the biocompatibility of five different naturally-produced biofilm chemical dispersal and inhibition signals with osteoblast-like cells: D-amino acids (D-AA), lysostaphin (LS), farnesol, cis-2-decenoic acid (C2DA), and desformyl flustrabromine (dFBr). In this preliminary study, compatibility of these anti-biofilm agents with differentiating osteoblasts was examined over a 21 days period at levels above and below concentrations active against bacterial biofilm. Anti-biofilm compounds listed above were serially diluted in osteogenic media and added to cultures of MC3T3 cells. Cell viability and cytotoxicity, after exposure to each anti-biofilm agent, were measured using a DNA assay. Differentiation characteristics of osteoblasts were determined qualitatively by observing staining of mineral deposits and quantitatively with an alkaline phosphatase assay. D-AA, LS, and C2DA were all biocompatible within the reported biofilm inhibitory concentration ranges and supported osteoblast differentiation. Farnesol and dFBr induced cytotoxic responses within the reported biofilm inhibitory concentration range and low doses of dFBr were found to inhibit osteoblast differentiation. At high concentrations, such as those that may be present after local delivery, many of these biofilm inhibitors can have effects on cellular viability and osteoblast function. Concentrations at which negative effects on osteoblasts occur should serve as upper limits for delivery to orthopaedic trauma sites and guide development of these potential therapeutics for orthopaedics. PMID:25505496

  4. Biological abatement of cellulase inhibitors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bio-abatement uses a fungus to metabolize and remove fermentation inhibitors. To determine whether bio-abatement could alleviate enzyme inhibitor effects observed in biomass liquors after pretreatment, corn stover at 10% (w/v) solids was pretreated with either dilute acid or liquid hot water. The ...

  5. Proteinaceous alpha-amylase inhibitors.

    PubMed

    Svensson, Birte; Fukuda, Kenji; Nielsen, Peter K; Bønsager, Birgit C

    2004-02-12

    Proteins that inhibit alpha-amylases have been isolated from plants and microorganisms. These inhibitors can have natural roles in the control of endogenous alpha-amylase activity or in defence against pathogens and pests; certain inhibitors are reported to be antinutritional factors. The alpha-amylase inhibitors belong to seven different protein structural families, most of which also contain evolutionary related proteins without inhibitory activity. Two families include bifunctional inhibitors acting both on alpha-amylases and proteases. High-resolution structures are available of target alpha-amylases in complex with inhibitors from five families. These structures indicate major diversity but also some similarity in the structural basis of alpha-amylase inhibition. Mutational analysis of the mechanism of inhibition was performed in a few cases and various protein engineering and biotechnological approaches have been outlined for exploitation of the inhibitory function. PMID:14871655

  6. Effect of ascorbate on plasminogen activator inhibitor-1 expression and release from platelets and endothelial cells in an in-vitro model of sepsis.

    PubMed

    Swarbreck, Scott B; Secor, Dan; Ellis, Christopher G; Sharpe, Michael D; Wilson, John X; Tyml, Karel

    2015-06-01

    The microcirculation during sepsis fails due to capillary plugging involving microthrombosis. We demonstrated that intravenous injection of ascorbate reduces this plugging, but the mechanism of this beneficial effect remains unclear. We hypothesize that ascorbate inhibits the release of the antifibrinolytic plasminogen activator inhibitor-1 (PAI-1) from endothelial cells and platelets during sepsis. Microvascular endothelial cells and platelets were isolated from mice. Cells were cultured and stimulated with lipopolysaccharide (LPS), tumor necrosis factor alpha (TNFα), or thrombin (agents of sepsis), with/without ascorbate for 1-24 h. PAI-1 mRNA was determined by quantitative PCR. PAI-1 protein release into the culture medium was measured by ELISA. In platelets, PAI-1 release was measured after LPS, TNFα, or thrombin stimulation, with/without ascorbate. In endothelial cells, LPS and TNFα increased PAI-1 mRNA after 6-24 h, but no increase in PAI-1 release was observed; ascorbate did not affect these responses. In platelets, thrombin, but not LPS or TNFα, increased PAI-1 release; ascorbate inhibited this increase at low extracellular pH. In unstimulated endothelial cells and platelets, PAI-1 is released into the extracellular space. Thrombin increases this release from platelets; ascorbate inhibits it pH-dependently. The data suggest that ascorbate promotes fibrinolysis in the microvasculature under acidotic conditions in sepsis. PMID:25730478

  7. Oxidized mucus proteinase inhibitor: a fairly potent neutrophil elastase inhibitor.

    PubMed Central

    Boudier, C; Bieth, J G

    1994-01-01

    N-chlorosuccinimide oxidizes one of the methionine residues of mucus proteinase inhibitor with a second-order rate constant of 1.5 M-1.s-1. Cyanogen bromide cleavage and NH2-terminal sequencing show that the modified residue is methionine-73, the P'1 component of the inhibitor's active centre. Oxidation of the inhibitor decreases its neutrophil elastase inhibitory capacity but does not fully abolish it. The kinetic parameters describing the elastase-oxidized inhibitor interaction are: association rate constant kass. = 2.6 x 10(5) M-1.s-1, dissociation rate constant kdiss. = 2.9 x 10(-3) s-1 and equilibrium dissociation constant Ki = 1.1 x 10(-8) M. Comparison with the native inhibitor indicates that oxidation decreases kass. by a factor of 18.8 and increases kdiss. by a factor of 6.4, and therefore leads to a 120-fold increase in Ki. Yet, the oxidized inhibitor may still act as a potent elastase inhibitor in the upper respiratory tract where its concentration is 500-fold higher than Ki, i.e. where the elastase inhibition is pseudo-irreversible. Experiments in vitro with fibrous human lung elastin, the most important natural substrate of elastase, support this view: 1.35 microM elastase is fully inhibited by 5-6 microM oxidized inhibitor whether the enzyme-inhibitor complex is formed in the presence or absence of elastin and whether elastase is pre-adsorbed on elastin or not. PMID:7945266

  8. Flavivirus Entry Inhibitors.

    PubMed

    Wang, Qing-Yin; Shi, Pei-Yong

    2015-09-11

    Many flaviviruses are significant human pathogens that are transmitted by mosquitoes and ticks. Although effective vaccines are available for yellow fever virus, Japanese encephalitic virus, and tick-borne encephalitis virus, these and other flaviviruses still cause thousands of human deaths and millions of illnesses each year. No clinically approved antiviral therapy is available for flavivirus treatment. To meet this unmet medical need, industry and academia have taken multiple approaches to develop antiflavivirus therapy, among which targeting viral entry has been actively pursued in the past decade. Here we review the current knowledge of flavivirus entry and its use for small molecule drug discovery. Inhibitors of two major steps of flaviviral entry have been reported: (i) molecules that block virus-receptor interaction; (ii) compounds that prevent conformational change of viral envelope protein during virus-host membrane fusion. We also discuss the advantages and disadvantages of targeting viral entry for treatment of flavivirus infection as compared to targeting viral replication proteins. PMID:27617926

  9. Synthetic conversion of ACAT inhibitor to acetylcholinesterase inhibitor.

    PubMed

    Obata, R; Sunazuka, T; Otoguro, K; Tomoda, H; Harigaya, Y; Omura, S

    2000-06-19

    Natural product acyl-CoA:cholesterol acyltransferase (ACAT) inhibitor pyripyropene A was synthetically converted to acetylcholinesterase (AChE) inhibitor via heterolitic cleavage of the 2-pyrone ring, followed by gamma-acylation/cyclization with several aroyl chlorides. The 4-pyridyl analogue selectively showed AChE inhibitory activity (IC50 7.9 microM) and no ACAT inhibitory activity IC50 = >1000 microM. PMID:10890154

  10. Factor XIIIa-dependent retention of red blood cells in clots is mediated by fibrin α-chain crosslinking.

    PubMed

    Byrnes, James R; Duval, Cédric; Wang, Yiming; Hansen, Caroline E; Ahn, Byungwook; Mooberry, Micah J; Clark, Martha A; Johnsen, Jill M; Lord, Susan T; Lam, Wilbur A; Meijers, Joost C M; Ni, Heyu; Ariëns, Robert A S; Wolberg, Alisa S

    2015-10-15

    Factor XIII(a) [FXIII(a)] stabilizes clots and increases resistance to fibrinolysis and mechanical disruption. FXIIIa also mediates red blood cell (RBC) retention in contracting clots and determines venous thrombus size, suggesting FXIII(a) is a potential target for reducing thrombosis. However, the mechanism by which FXIIIa retains RBCs in clots is unknown. We determined the effect of FXIII(a) on human and murine clot weight and composition. Real-time microscopy revealed extensive RBC loss from clots formed in the absence of FXIIIa activity, and RBCs exhibited transient deformation as they exited the clots. Fibrin band-shift assays and flow cytometry did not reveal crosslinking of fibrin or FXIIIa substrates to RBCs, suggesting FXIIIa does not crosslink RBCs directly to the clot. RBCs were retained in clots from mice deficient in α2-antiplasmin, thrombin-activatable fibrinolysis inhibitor, or fibronectin, indicating RBC retention does not depend on these FXIIIa substrates. RBC retention in clots was positively correlated with fibrin network density; however, FXIIIa inhibition reduced RBC retention at all network densities. FXIIIa inhibition reduced RBC retention in clots formed with fibrinogen that lacks γ-chain crosslinking sites, but not in clots that lack α-chain crosslinking sites. Moreover, FXIIIa inhibitor concentrations that primarily block α-, but not γ-, chain crosslinking decreased RBC retention in clots. These data indicate FXIIIa-dependent retention of RBCs in clots is mediated by fibrin α-chain crosslinking. These findings expose a newly recognized, essential role for fibrin crosslinking during whole blood clot formation and consolidation and establish FXIIIa activity as a key determinant of thrombus composition and size. PMID:26324704

  11. Low-molecular-weight heparin modulates vein wall fibrotic response in a plasminogen activator inhibitor 1-dependent manner

    PubMed Central

    Obi, Andrea T.; Diaz, Jose A.; Ballard-Lipka, Nicole L.; Roelofs, Karen J.; Farris, Diana M.; Lawrence, Daniel A.; Henke, Peter K.; Wakefield, Thomas W.

    2014-01-01

    Background Treatment with low-molecular-weight heparin (LMWH) favorably alters the vein wall response to deep venous thrombosis (DVT), although the mechanisms remain unclear. Previous studies have suggested that LMWH alters the levels of circulating plasminogen activator inhibitor 1 (PAI-1), a known mediator of fibrosis, and may improve endogenous fibrinolysis. We hypothesized that LMWH favorably alters the vein wall response by binding of PAI-1 and acceleration of fibrinolysis. Methods Wild-type and PAI-1 −/− mice underwent treatment with LMWH after induction of occlusive DVT. Vein wall and plasma were harvested and analyzed by enzyme-linked immunosorbent assay, zymography, real-time polymerase chain reaction, and immunohistochemistry. Results Wild-type mice treated with LMWH exhibited diminished vein wall fibrosis (0.6 ± 0.6 vs 1.4 ± 0.2; P < .01; n = 5) and elevation of circulating PAI-1 (1776 ± 342 vs 567 ± 104 ρg/mL; P < .01; n = 5) compared with untreated controls after occlusive DVT. PAI-1−/− mice treated with LMWH were not similarly protected from fibrosis, despite improved thrombus resolution. Treatment with LMWH was associated with decreased intrathrombus interleukin-lβ (68.6 ± 31.0 vs 223.4 ± 28.9 ρg/mg total protein; P < .01; n = 5) but did not alter inflammatory cell recruitment to the vein wall. PAI-1 −/− mice exhibited significantly elevated intrathrombus (257.2 ± 51.5 vs 4.3 ± 3.8 ρg/mg total protein; n = 5) and vein wall interleukin-13 (187.2 ± 57.6 vs 9.9 ± 1.1 ρg/mg total protein; P < .05; n = 5) as well as vein wall F4/80 positively staining monocytes (53 ± 11 vs 16 ± 2 cells/5 high-power fields; P < .05; n = 4). Conclusions LMWH did not accelerate venous thrombosis resolution but did protect against vein wall fibrosis in a PAI-1-dependent manner in an occlusive DVT model. Lack of PAI-1 correlated with accelerated venous thrombosis resolution but no protection from fibrosis. PAI-1 inhibition as a treatment strategy

  12. Synthesis of lysine methyltransferase inhibitors

    PubMed Central

    Hui, Chunngai; Ye, Tao

    2015-01-01

    Lysine methyltransferase which catalyze methylation of histone and non-histone proteins, play a crucial role in diverse biological processes and has emerged as a promising target for the development of various human diseases, including cancer, inflammation, and psychiatric disorders. However, inhibiting lysine methyltransferases selectively has presented many challenges to medicinal chemists. During the past decade, lysine methyltransferase inhibitors covering many different structural classes have been designed and developed. In this review, we describe the development of selective, small-molecule inhibitors of lysine methyltransferases with an emphasis on their discovery and chemical synthesis. We highlight the current state of lysine methyltransferase inhibitors and discuss future directions and opportunities for lysine methyltransferase inhibitor discovery. PMID:26258118

  13. Targeting cancer with kinase inhibitors

    PubMed Central

    Gross, Stefan; Rahal, Rami; Stransky, Nicolas; Lengauer, Christoph; Hoeflich, Klaus P.

    2015-01-01

    Kinase inhibitors have played an increasingly prominent role in the treatment of cancer and other diseases. Currently, more than 25 oncology drugs that target kinases have been approved, and numerous additional therapeutics are in various stages of clinical evaluation. In this Review, we provide an in-depth analysis of activation mechanisms for kinases in cancer, highlight recent successes in drug discovery, and demonstrate the clinical impact of selective kinase inhibitors. We also describe the substantial progress that has been made in designing next-generation inhibitors to circumvent on-target resistance mechanisms, as well as ongoing strategies for combining kinase inhibitors in the clinic. Last, there are numerous prospects for the discovery of novel kinase targets, and we explore cancer immunotherapy as a new and promising research area for studying kinase biology. PMID:25932675

  14. Aromatase inhibitors for male infertility.

    PubMed

    Schlegel, Peter N

    2012-12-01

    Some men with severely defective sperm production commonly have excess aromatase activity, reflected by low serum testosterone and relatively elevated estradiol levels. Aromatase inhibitors can increase endogenous testosterone production and serum testosterone levels. Treatment of infertile males with the aromatase inhibitors testolactone, anastrazole, and letrozole has been associated with increased sperm production and return of sperm to the ejaculate in men with non-obstructive azoospermia. Use of the aromatase inhibitors anastrazole (1 mg/day) and letrozole (2.5 mg/day) represent off-label use of these agents for impaired spermatogenesis in men with excess aromatase activity (abnormal testosterone/estradiol [T/E] ratios). Side effects have rarely been reported. Randomized controlled trials are needed to define the magnitude of benefit of aromatase inhibitor treatment for infertile men. PMID:23103016

  15. Selective Inhibitors of Protein Methyltransferases

    PubMed Central

    2015-01-01

    Mounting evidence suggests that protein methyltransferases (PMTs), which catalyze methylation of histone and nonhistone proteins, play a crucial role in diverse biological processes and human diseases. In particular, PMTs have been recognized as major players in regulating gene expression and chromatin state. PMTs are divided into two categories: protein lysine methyltransferases (PKMTs) and protein arginine methyltransferases (PRMTs). There has been a steadily growing interest in these enzymes as potential therapeutic targets and therefore discovery of PMT inhibitors has also been pursued increasingly over the past decade. Here, we present a perspective on selective, small-molecule inhibitors of PMTs with an emphasis on their discovery, characterization, and applicability as chemical tools for deciphering the target PMTs’ physiological functions and involvement in human diseases. We highlight the current state of PMT inhibitors and discuss future directions and opportunities for PMT inhibitor discovery. PMID:25406853

  16. [Cancer therapy by PARP inhibitors].

    PubMed

    Seimiya, Hiroyuki

    2015-08-01

    Poly(ADP-ribose) polymerases(PARP) synthesize the ADP-ribose polymers onto proteins and play a role in DNA repair. PARP inhibitors block the repair of single-strand breaks, which in turn gives rise to double-strand breaks during DNA replication. Thus, PARP inhibitors elicit synthetic lethality in cancer with BRCA1/2 loss-of-function mutations that hamper homologous recombination repair of double-strand breaks. Olaparib, the first-in-class PARP inhibitor, was approved for treatment of BRCA-mutated ovarian cancer in Europe and the United States in 2014. Other PARP inhibitors under clinical trials include rucaparib, niraparib, veliparib, and the "PARP-trapping" BMN-673. BRCA1/2 sequencing is an FDA-approved companion diagnostics, which predicts the cancer vulnerability to PARP inhibition. Together, synthetic lethal PARP inhibition is a novel promising strategy for cancer intervention even in cases without prominent driver oncogenes. PMID:26281686

  17. [Pharmacology of bone resorption inhibitor].

    PubMed

    Menuki, Kunitaka; Sakai, Akinori

    2015-10-01

    Currently, bone resorption inhibitor is mainly used for osteoporosis. A number of these agents have been developed. These pharmacological action are various. Bisphosphonate inhibit functions of the osteoclasts by inducing apoptosis. On the one hand, RANK-ligand inhibitor and selective estrogen receptor modulator inhibit formation of osteoclasts. It is important to understand these pharmacological action for the selection of the appropriate medicine. PMID:26529923

  18. The profibrinolytic enzyme subtilisin NAT purified from Bacillus subtilis Cleaves and inactivates plasminogen activator inhibitor type 1.

    PubMed

    Urano, T; Ihara, H; Umemura, K; Suzuki, Y; Oike, M; Akita, S; Tsukamoto, Y; Suzuki, I; Takada, A

    2001-07-01

    In this report, we demonstrate an interaction between subtilisin NAT (formerly designated BSP, or nattokinase), a profibrinolytic serine proteinase from Bacillus subtilis, and plasminogen activator inhibitor 1 (PAI-1). Subtilisin NAT was purified to homogeneity (molecular mass, 27.7 kDa) from a saline extract of B. subtilis (natto). Subtilisin NAT appeared to cleave active recombinant prokaryotic PAI-1 (rpPAI-1) into low molecular weight fragments. Matrix-assisted laser desorption/ionization in combination with time-of-flight mass spectroscopy and peptide sequence analysis revealed that rpPAI-1 was cleaved at its reactive site (P1-P1': Arg(346)-Met(347)). rpPAI-1 lost its specific activity after subtilisin NAT treatment in a dose-dependent manner (0.02-1.0 nm; half-maximal effect at approximately 0.1 nm). Subtilisin NAT dose dependently (0.06-1 nm) enhanced tissue-type plasminogen activator-induced fibrin clot lysis both in the absence of rpPAI-1 (48 +/- 1.4% at 1 nm) and especially in the presence of rpPAI-1 (78 +/- 2.0% at 1 nm). The enhancement observed in the absence of PAI-1 seems to be induced through direct fibrin dissolution by subtilisin NAT. The stronger enhancement by subtilisin NAT of rpPAI-1-enriched fibrin clot lysis seems to involve the cleavage and inactivation of active rpPAI-1. This mechanism is suggested to be important for subtilisin NAT to potentiate fibrinolysis. PMID:11325965

  19. Copper(II) Ions Increase Plasminogen Activator Inhibitor Type 1 Dynamics in Key Structural Regions That Govern Stability.

    PubMed

    Bucci, Joel C; Trelle, Morten Beck; McClintock, Carlee S; Qureshi, Tihami; Jørgensen, Thomas J D; Peterson, Cynthia B

    2016-08-01

    Plasminogen activator inhibitor type 1 (PAI-1) regulates the fibrinolysis pathway by inhibiting the protease activity of plasminogen activators. PAI-1 works in concert with vitronectin (VN), an extracellular protein that aids in localization of active PAI-1 to tissues. The Peterson laboratory demonstrated that Cu(II) and other transition metals modulate the stability of PAI-1, exhibiting effects that are dependent on the presence or absence of the somatomedin B (SMB) domain of VN. The study presented here dissects the changes in molecular dynamics underlying the destabilizing effects of Cu(II) on PAI-1. We utilize backbone amide hydrogen/deuterium exchange monitored by mass spectrometry to assess PAI-1 dynamics in the presence and absence of Cu(II) ions with and without the SMB domain of VN. We show that Cu(II) produces an increase in dynamics in regions important for the function and overall stability of PAI-1, while the SMB domain elicits virtually the opposite effect. A mutant form of PAI-1 lacking two N-terminal histidine residues at positions 2 and 3 exhibits similar increases in dynamics upon Cu(II) binding compared to that of active wild-type PAI-1, indicating that the observed structural effects are not a result of coordination of Cu(II) to these histidine residues. Finally, addition of Cu(II) results in an acceleration of the local unfolding kinetics of PAI-1 presumed to be on pathway to the latency conversion. The effect of ligands on the dynamics of PAI-1 adds another intriguing dimension to the mechanisms for regulation of PAI-1 stability and function. PMID:27416303

  20. Corrosion inhibitor selection for wet pipelines

    SciTech Connect

    Buck, E.

    1995-12-31

    Selection of corrosion inhibitors for wet pipelines is based on laboratory testing and field confirmation. Both the use and selection of corrosion inhibitors are driven by economics. Economics of alternative corrosion protection methods is not treated in this paper, but the economics of proper inhibitor selection are. The key to successful inhibitor selection is careful analysis of pipeline flow conditions and experimental emulation of its corrosive environment. Transportation of inhibitor to the corroding interface must be explicitly considered in the emulation. Standard corrosion rate measurement methods are used to evaluate inhibitors. Inhibitor properties tabulated during evaluation form a core database for continuing quality control.

  1. [The synthesis of specific enzyme inhibitors].

    PubMed

    Iakovleva, G M

    1987-04-01

    The review deals with directed synthesis of specific enzyme inhibitors. They are classified within the framework of the mechanistic approach, namely, stable analogues of substrates, which form enzyme complexes mimicking the Michaelis complex or those which influence the chemical stages of enzyme catalysis; conformational inhibitors; substrate analogues participating in enzyme reactions and producing modified products; suicide inhibitors; stage inhibitors (inhibitors influencing certain stages of enzyme reaction); transition state analogues; multisubstrate analogues and collected substrates. Types of chemical modification used in synthesis of the specific inhibitors are discussed. Some possibilities of the quantity structure-activity relationship methods, computer modelling and molecular graphics in designing the optimal structure of inhibitors are mentioned. PMID:3300658

  2. Pharmacology of phosphodiesterase-5 inhibitors.

    PubMed

    Corbin, J D; Francis, S H

    2002-01-01

    The clinical properties (efficacy and safety profile) of a medicine are related not only to its mode of action, but also to its selectivity for its target (usually a receptor or enzyme) and are also influenced by its pharmacokinetic properties (absorption, distribution, metabolism and elimination). The growing number of phosphodiesterase inhibitors that are selective for phosphodiesterase-5 (PDE5) represent a promising new class of compounds that are useful for the treatment of erectile dysfunction and perhaps other disorders. Some of the basic pharmacodynamic and pharmacokinetic parameters that describe drug action are discussed with regard to the new PDE5 inhibitors. Central topics reviewed are the concentration that produces a given in vitro response, or potency (IC50), maximum plasma concentration (Cmax), time to Cmax (Tmax), half-life (t 1/2), area under the curve (AUC), bioavailability, onset and duration of action, and the balance to achieve optimum safety and efficacy. To illustrate these concepts, a group of inhibitors with varying selectivities and potencies for PDE5 (theophylline, IBMX, zaprinast, sildenafil, tadalafil and vardenafil) are discussed. Each drug has its own set of unique pharmacological characteristics based on its specific molecular structure, enzyme inhibition profile and pharmacokinetic properties. Each PDE5 inhibitor has a distinct selectivity that contributes to its safety profile. As with all new drugs, and especially those in a new class, careful evaluation will be necessary to ensure the optimal use of the PDE5 inhibitors. PMID:12166544

  3. Evolutionary families of peptidase inhibitors.

    PubMed Central

    Rawlings, Neil D; Tolle, Dominic P; Barrett, Alan J

    2004-01-01

    The proteins that inhibit peptidases are of great importance in medicine and biotechnology, but there has never been a comprehensive system of classification for them. Some of the terminology currently in use is potentially confusing. In the hope of facilitating the exchange, storage and retrieval of information about this important group of proteins, we now describe a system wherein the inhibitor units of the peptidase inhibitors are assigned to 48 families on the basis of similarities detectable at the level of amino acid sequence. Then, on the basis of three-dimensional structures, 31 of the families are assigned to 26 clans. A simple system of nomenclature is introduced for reference to each clan, family and inhibitor. We briefly discuss the specificities and mechanisms of the interactions of the inhibitors in the various families with their target enzymes. The system of families and clans of inhibitors described has been implemented in the MEROPS peptidase database (http://merops.sanger.ac.uk/), and this will provide a mechanism for updating it as new information becomes available. PMID:14705960

  4. Microbial inhibitors of cysteine proteases.

    PubMed

    Kędzior, Mateusz; Seredyński, Rafał; Gutowicz, Jan

    2016-08-01

    Cysteine proteases are one of the major classes of proteolytic enzymes involved in a number of physiological and pathological processes in plants, animals and microorganisms. When their synthesis, activity and localization in mammalian cells are altered, they may contribute to the development of many diseases, including rheumatoid arthritis, osteoporosis and cancer. Therefore, cysteine proteases have become promising drug targets for the medical treatment of these disorders. Inhibitors of cysteine proteases are also produced by almost every group of living organisms, being responsible for the control of intracellular proteolytic activity. Microorganisms synthesize cysteine protease inhibitors not only to regulate the activity of endogenous, often virulent enzymes, but also to hinder the host's proteolytic defense system and evade its immune responses against infections. Present work describes known to date microbial inhibitors of cysteine proteases in terms of their structure, enzyme binding mechanism, specificity and pathophysiological roles. The overview of both proteinaceous and small-molecule inhibitors produced by all groups of microorganisms (bacteria, archaea, fungi, protists) and viruses is provided. Subsequently, possible applications of microbial inhibitors in science, medicine and biotechnology are also highlighted. PMID:27048482

  5. Electrochemical studies of corrosion inhibitors

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1990-01-01

    The effect of single salts, as well as multicomponent mixtures, on corrosion inhibition was studied for type 1010 steel; for 5052, 1100, and 2219-T87 aluminum alloys; and for copper. Molybdate-containing inhibitors exhibit an immediate, positive effect for steel corrosion, but an incubation period may be required for aluminum before the effect of a given inhibitor can be determined. The absence of oxygen was found to provide a positive effect (smaller corrosion rate) for steel and copper, but a negative effect for aluminum. This is attributed to the two possible mechanisms by which aluminum can oxidize. Corrosion inhibition is generally similar for oxygen-rich and oxygen-free environments. The results show that the electrochemical method is an effective means of screening inhibitors for the corrosion of single metals, with caution to be exercised in the case of aluminum.

  6. Positron emitter labeled enzyme inhibitors

    DOEpatents

    Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.

    1987-05-22

    This invention involved a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide in activators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography. 2 figs.

  7. Positron emitter labeled enzyme inhibitors

    DOEpatents

    Fowler, Joanna S.; MacGregor, Robert R.; Wolf, Alfred P.; Langstrom, Bengt

    1990-01-01

    This invention involves a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography.

  8. Corrosion inhibitors from expired drugs.

    PubMed

    Vaszilcsin, Nicolae; Ordodi, Valentin; Borza, Alexandra

    2012-07-15

    This paper presents a method of expired or unused drugs valorization as corrosion inhibitors for metals in various media. Cyclic voltammograms were drawn on platinum in order to assess the stability of pharmaceutically active substances from drugs at the metal-corrosive environment interface. Tafel slope method was used to determine corrosion rates of steel in the absence and presence of inhibitors. Expired Carbamazepine and Paracetamol tablets were used to obtain corrosion inhibitors. For the former, the corrosion inhibition of carbon steel in 0.1 mol L(-1) sulfuric acid solution was about 90%, whereas for the latter, the corrosion inhibition efficiency of the same material in the 0.25 mol L(-1) acetic acid-0.25 mol L(-1) sodium acetate buffer solution was about 85%. PMID:22561212

  9. Positron emitter labeled enzyme inhibitors

    SciTech Connect

    Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.; Langstrom, B.

    1990-04-03

    This invention involves a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography.

  10. Monoglyceride lipase: Structure and inhibitors.

    PubMed

    Scalvini, Laura; Piomelli, Daniele; Mor, Marco

    2016-05-01

    Monoglyceride lipase (MGL), the main enzyme responsible for the hydrolytic deactivation of the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG), is an intracellular serine hydrolase that plays critical roles in many physiological and pathological processes, such as pain, inflammation, neuroprotection and cancer. The crystal structures of MGL that are currently available provide valuable information about how this enzyme might function and interact with site-directed small-molecule inhibitors. On the other hand, its conformational equilibria and the contribution of regulatory cysteine residues present within the substrate-binding pocket or on protein surface remain open issues. Several classes of MGL inhibitors have been developed, from early reversible ones, such as URB602 and pristimerin, to carbamoylating agents that react with the catalytic serine, such as JZL184 and more recent O-hexafluoroisopropyl carbamates. Other inhibitors that modulate MGL activity by interacting with conserved regulatory cysteines act through mechanisms that deserve to be more thoroughly investigated. PMID:26216043

  11. STAT inhibitors for cancer therapy

    PubMed Central

    2013-01-01

    Signal Transducer and Activator of Transcription (STAT) proteins are a family of cytoplasmic transcription factors consisting of 7 members, STAT1 to STAT6, including STAT5a and STAT5b. STAT proteins are thought to be ideal targets for anti-cancer therapy since cancer cells are more dependent on the STAT activity than their normal counterparts. Inhibitors targeting STAT3 and STAT5 have been developed. These included peptidomimetics, small molecule inhibitors and oligonucleotides. This review summarized advances in preclinical and clinical development of these compounds. PMID:24308725

  12. SGLT2 inhibitors: new reports.

    PubMed

    2015-10-12

    A significant decrease in cardiovascular mortality has been reported with use of the SGLT2 inhibitor empagliflozin (Jardiance) to treat patients with type 2 diabetes who have established cardiovascular disease. The mechanism of this reduction is unclear, and these results may not apply to patients with type 2 diabetes and less advanced cardiovascular disease. Whether the increase in fractures reported with canagliflozin (Invokana) could also occur with empagliflozin remains to be established. All SGLT2 inhibitors are only modestly effective for treatment of diabetes. PMID:26445203

  13. Structural basis of specific inhibition of tissue-type plasminogen activator by plasminogen activators inhibitor-1

    PubMed Central

    Gong, Lihu; Liu, Min; Zeng, Tu; Shi, Xiaoli; Yuan, Cai; Andreasen, Peter A.; Huang, Mingdong

    2016-01-01

    Thrombosis is a leading cause of death worldwide [1]. Recombinant tissue-type plasminogen activator (tPA) is the FDA-approved thrombolytic drug for ischemic strokes, myocardial infarction and pulmonary embolism. tPA is a multi-domain serine protease of the trypsin-family [2] and catalyses the critical step in fibrinolysis [3], converting the zymogen plasminogen to the active serine protease plasmin, which degrades the fibrin network of thrombi and blood clots. tPA is rapidly inactivated by endogenous plasminogen activators inhibitor-1 (PAI-1) [4] (Fig. 1). Engineering on tPA to reduce its inhibition by PAI-1 without compromising its thrombolytic effect is a continuous effort [5]. Tenecteplase (TNK-tPA) is a newer generation of tPA variant showing slower inhibition by PAI-1 [6]. Extensive studies to understand the molecular interactions between tPA and PAI-1 have been carried out [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], however, the precise details at atomic resolution remain unknown. We report the crystal structure of tPA·PAI-1 complex here. The methods required to achieve these data include: (1) recombinant expression and purification of a PAI-1 variant (14-1B) containing four mutations (N150H, K154T, Q319L, and M354I), and a tPA serine protease domain (tPA-SPD) variant with three mutations (C122A, N173Q, and S195A, in the chymotrypsin numbering) [19]; (2) formation of a tPA-SPD·PAI-1 Michaëlis complex in vitro [19]; and (3) solving the three-dimensional structure for this complex by X-ray crystallography [deposited in the PDB database as 5BRR]. The data explain the specificity of PAI-1 for tPA and uPA [19], [20], and provide structural basis to design newer generation of PAI-1-resistant tPA variants as thrombolytic agents [19]. PMID:26909366

  14. Structural basis of specific inhibition of tissue-type plasminogen activator by plasminogen activators inhibitor-1.

    PubMed

    Gong, Lihu; Liu, Min; Zeng, Tu; Shi, Xiaoli; Yuan, Cai; Andreasen, Peter A; Huang, Mingdong

    2016-03-01

    Thrombosis is a leading cause of death worldwide [1]. Recombinant tissue-type plasminogen activator (tPA) is the FDA-approved thrombolytic drug for ischemic strokes, myocardial infarction and pulmonary embolism. tPA is a multi-domain serine protease of the trypsin-family [2] and catalyses the critical step in fibrinolysis [3], converting the zymogen plasminogen to the active serine protease plasmin, which degrades the fibrin network of thrombi and blood clots. tPA is rapidly inactivated by endogenous plasminogen activators inhibitor-1 (PAI-1) [4] (Fig. 1). Engineering on tPA to reduce its inhibition by PAI-1 without compromising its thrombolytic effect is a continuous effort [5]. Tenecteplase (TNK-tPA) is a newer generation of tPA variant showing slower inhibition by PAI-1 [6]. Extensive studies to understand the molecular interactions between tPA and PAI-1 have been carried out [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], however, the precise details at atomic resolution remain unknown. We report the crystal structure of tPA·PAI-1 complex here. The methods required to achieve these data include: (1) recombinant expression and purification of a PAI-1 variant (14-1B) containing four mutations (N150H, K154T, Q319L, and M354I), and a tPA serine protease domain (tPA-SPD) variant with three mutations (C122A, N173Q, and S195A, in the chymotrypsin numbering) [19]; (2) formation of a tPA-SPD·PAI-1 Michaëlis complex in vitro [19]; and (3) solving the three-dimensional structure for this complex by X-ray crystallography [deposited in the PDB database as 5BRR]. The data explain the specificity of PAI-1 for tPA and uPA [19], [20], and provide structural basis to design newer generation of PAI-1-resistant tPA variants as thrombolytic agents [19]. PMID:26909366

  15. Biocatalysts with enhanced inhibitor tolerance

    DOEpatents

    Yang, Shihui; Linger, Jeffrey; Franden, Mary Ann; Pienkos, Philip T.; Zhang, Min

    2015-12-08

    Disclosed herein are biocatalysts for the production of biofuels, including microorganisms that contain genetic modifications conferring tolerance to growth and fermentation inhibitors found in many cellulosic feedstocks. Methods of converting cellulose-containing materials to fuels and chemicals, as well as methods of fermenting sugars to fuels and chemicals, using these biocatalysts are also disclosed.

  16. Acetylcholinesterase Inhibitors: Pharmacology and Toxicology

    PubMed Central

    Čolović, Mirjana B; Krstić, Danijela Z; Lazarević-Pašti, Tamara D; Bondžić, Aleksandra M; Vasić, Vesna M

    2013-01-01

    Acetylcholinesterase is involved in the termination of impulse transmission by rapid hydrolysis of the neurotransmitter acetylcholine in numerous cholinergic pathways in the central and peripheral nervous systems. The enzyme inactivation, induced by various inhibitors, leads to acetylcholine accumulation, hyperstimulation of nicotinic and muscarinic receptors, and disrupted neurotransmission. Hence, acetylcholinesterase inhibitors, interacting with the enzyme as their primary target, are applied as relevant drugs and toxins. This review presents an overview of toxicology and pharmacology of reversible and irreversible acetylcholinesterase inactivating compounds. In the case of reversible inhibitors being commonly applied in neurodegenerative disorders treatment, special attention is paid to currently approved drugs (donepezil, rivastigmine and galantamine) in the pharmacotherapy of Alzheimer’s disease, and toxic carbamates used as pesticides. Subsequently, mechanism of irreversible acetylcholinesterase inhibition induced by organophosphorus compounds (insecticides and nerve agents), and their specific and nonspecific toxic effects are described, as well as irreversible inhibitors having pharmacological implementation. In addition, the pharmacological treatment of intoxication caused by organophosphates is presented, with emphasis on oxime reactivators of the inhibited enzyme activity administering as causal drugs after the poisoning. Besides, organophosphorus and carbamate insecticides can be detoxified in mammals through enzymatic hydrolysis before they reach targets in the nervous system. Carboxylesterases most effectively decompose carbamates, whereas the most successful route of organophosphates detoxification is their degradation by corresponding phosphotriesterases. PMID:24179466

  17. Less-toxic corrosion inhibitors

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1981-01-01

    Combinations of borates, nitrates, phosphates, silicates, and sodium MBT protect aluminum from corrosion in fresh water. Most effective combinations contained sodium phosphate and were alkaline. These inhibitors replace toxic chromates which are subject to governmental restrictions, but must be used in larger quantities. Experimental exposure times varied from 1 to 14 months depending upon nature of submersion solution.

  18. Structures of Potent Selective Peptide Mimetics Bound to Carboxypeptidase B

    SciTech Connect

    Adler, M.; Buckman, B.; Bryant, J.; Chang, Z.; Chu, K.; Emayan, K.; Hrvatin, P.; Islam, I.; Morser, J.; Sukovich, D.; West, C.; Yuan, S.; Whitlow, M.

    2009-05-11

    This article reports the crystal structures of inhibitors of the functional form of thrombin-activatable fibrinolysis inhibitor (TAFIa). In vivo experiments indicate that selective inhibitors of TAFIa would be useful in the treatment of heart attacks. Since TAFIa rapidly degrades in solution, the homologous protein porcine pancreatic carboxypeptidase B (pp-CpB) was used in these crystallography studies. Both TAFIa and pp-CpB are zinc-based exopeptidases that are specific for basic residues. The final development candidate, BX 528, is a potent inhibitor of TAFIa (2 nM) and has almost no measurable effect on the major selectivity target, carboxypeptidase N. BX 528 was designed to mimic the tripeptide Phe-Val-Lys. A sulfonamide replaces the Phe-Val amide bond and a phosphinate connects the Val and Lys groups. The phosphinate also chelates the active-site zinc. The electrostatic interactions with the protein mimic those of the natural substrate. The primary amine in BX 528 forms a salt bridge to Asp255 at the base of the S1 pocket. The carboxylic acid interacts with Arg145 and the sulfonamide is hydrogen bonded to Arg71. Isopropyl and phenyl groups replace the side chains of Val and Phe, respectively. A series of structures are presented here that illustrate the evolution of BX 528 from thiol-based inhibitors that mimic a free C-terminal arginine. The first step in development was the replacement of the thiol with a phosphinate. This caused a precipitous drop in binding affinity. Potency was reclaimed by extending the inhibitors into the downstream binding sites for the natural substrate.

  19. Aromatase Inhibitors and Other Compounds for Lowering Breast Cancer Risk

    MedlinePlus

    ... References Aromatase inhibitors and other compounds for lowering breast cancer risk Aromatase inhibitors (drugs that lower estrogen levels) ... day. Can aromatase inhibitors lower the risk of breast cancer? Aromatase inhibitors are used mainly to treat hormone ...

  20. Salicylanilide Inhibitors of Toxoplasma gondii

    PubMed Central

    Fomovska, Alina; Wood, Richard D.; Mui, Ernest; Dubey, Jitenter P.; Ferriera, Leandra R.; Hickman, Mark R.; Lee, Patricia J.; Leed, Susan E.; Auschwitz, Jennifer M.; Welsh, William J.; Sommerville, Caroline; Woods, Stuart; Roberts, Craig; McLeod, Rima

    2012-01-01

    Toxoplasma gondii(T. gondii) is an apicomplexan parasite that can cause eye disease, brain disease, and death, especially in congenitally infected and immune-compromised people. Novel medicines effective against both active and latent forms of the parasite are greatly needed. The current study focused on the discovery of such medicines by exploring a family of potential inhibitors whose anti-apicomplexan activity has not been previously reported. Initial screening efforts revealed that niclosamide, a drug approved for anthelmintic use, possessed promising activity in vitro against T. gondii. This observation inspired the evaluation of the activity of a series of salicylanilides and derivatives. Several inhibitors with activities in the nanomolar range with no appreciable in vitro toxicity to human cells were identified. An initial structure-activity relationship was explored. Four compounds were selected for evaluation in an in vivo model of infection, and two derivatives with potentially enhanced pharmacological parameters demonstrated the best activity profiles. PMID:22970937

  1. Macrocyclic compounds as corrosion inhibitors

    SciTech Connect

    Quraishi, M.A.; Rawat, J.; Ajmal, M.

    1998-12-01

    The influence of three macrocyclic compounds on corrosion of mild steel (MS) in hydrochloric acid (HCl) was investigated using weight loss, potentiodynamic polarization, alternating current (AC) impedance, and hydrogen permeation techniques. All the investigated compounds showed significant efficiencies and reduced permeation of hydrogen through MS in HCl. Inhibition efficiency (IE) varied with the nature and concentrations of the inhibitors, temperature, and concentrations of the acid solutions. The addition of iodide ions (I{sup {minus}}) increased IE of all the tested compounds as a result of the synergistic effect. Potentiodynamic polarization results revealed that macrocyclic compounds acted as mixed inhibitors in 1 M HCl to 5 M HCl. Adsorption on the metal surface obeyed Temkin`s adsorption isotherm. Auger electron spectroscopy (AES) of the polished MS surface, exposed with tetraphenyldithia-octaazacyclotetradeca-hexaene (PTAT) proved adsorption of this compound on the surface through nitrogen and sulfur atoms.

  2. [Proteasome inhibitors in cancer therapy].

    PubMed

    Romaniuk, Wioletta; Ołdziej, Agnieszka Ewa; Zińczuk, Justyna; Kłoczko, Janusz

    2015-01-01

    Proteasomes are multisubunit enzyme complexes. They contain three enzymatic active sites which are termed chymotrypsin-like, trypsin-like, and caspase-like. The elementary function of the proteasomes is degradation of damaged proteins. Proteasome inhibition leads to accumulation of damaged protein, which leads to caspase activation and cell death. This relationship is used in cancer therapy. Bortezomib is the first proteasome inhibitor approved by the US Food and Drug Administration for the treatment of relapsed/refractory multiple myeloma. Carfilzomib belongs to the second generation of drugs, which was approved by the US FDA in 2012. Currently in the study phase there are four new inhibitors: ixazomib (MLN9780/MLN2238), delanzomib (CEP-18770), oprozomib (ONX0912/PR-047) and marizomib (NPI-0052). PMID:27259216

  3. Thioredoxin Reductase and its Inhibitors

    PubMed Central

    Saccoccia, Fulvio; Angelucci, Francesco; Boumis, Giovanna; Carotti, Daniela; Desiato, Gianni; Miele, Adriana E; Bellelli, Andrea

    2014-01-01

    Thioredoxin plays a crucial role in a wide number of physiological processes, which span from reduction of nucleotides to deoxyriboucleotides to the detoxification from xenobiotics, oxidants and radicals. The redox function of Thioredoxin is critically dependent on the enzyme Thioredoxin NADPH Reductase (TrxR). In view of its indirect involvement in the above mentioned physio/pathological processes, inhibition of TrxR is an important clinical goal. As a general rule, the affinities and mechanisms of binding of TrxR inhibitors to the target enzyme are known with scarce precision and conflicting results abound in the literature. A relevant analysis of published results as well as the experimental procedures is therefore needed, also in view of the critical interest of TrxR inhibitors. We review the inhibitors of TrxR and related flavoreductases and the classical treatment of reversible, competitive, non competitive and uncompetitive inhibition with respect to TrxR, and in some cases we are able to reconcile contradictory results generated by oversimplified data analysis. PMID:24875642

  4. Carbonic anhydrase inhibitors drug design.

    PubMed

    McKenna, Robert; Supuran, Claudiu T

    2014-01-01

    Inhibition of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) has pharmacologic applications in the field of antiglaucoma, anticonvulsant, antiobesity, and anticancer agents but is also emerging for designing anti-infectives (antifungal and antibacterial agents) with a novel mechanism of action. As a consequence, the drug design of CA inhibitors (CAIs) is a very dynamic field. Sulfonamides and their isosteres (sulfamates/sulfamides) constitute the main class of CAIs which bind to the metal ion in the enzyme active site. Recently the dithiocarbamates, possessing a similar mechanism of action, were reported as a new class of inhibitors. Other families of CAIs possess a distinct mechanism of action: phenols, polyamines, some carboxylates, and sulfocoumarins anchor to the zinc-coordinated water molecule. Coumarins and five/six-membered lactones are prodrug inhibitors, binding in hydrolyzed form at the entrance of the active site cavity. Novel drug design strategies have been reported principally based on the tail approach for obtaining all these types of CAIs, which exploit more external binding regions within the enzyme active site (in addition to coordination to the metal ion), leading thus to isoform-selective compounds. Sugar-based tails as well as click chemistry were the most fruitful developments of the tail approach. Promising compounds that inhibit CAs from bacterial and fungal pathogens, of the dithiocarbamate, phenol and carboxylate types have also been reported. PMID:24146385

  5. Bromodomains and their pharmacological inhibitors.

    PubMed

    Gallenkamp, Daniel; Gelato, Kathy A; Haendler, Bernard; Weinmann, Hilmar

    2014-03-01

    Over 60 bromodomains belonging to proteins with very different functions have been identified in humans. Several of them interact with acetylated lysine residues, leading to the recruitment and stabilization of protein complexes. The bromodomain and extra-terminal domain (BET) proteins contain tandem bromodomains which bind to acetylated histones and are thereby implicated in a number of DNA-centered processes, including the regulation of gene expression. The recent identification of inhibitors of BET and non-BET bromodomains is one of the few examples in which effective blockade of a protein-protein interaction can be achieved with a small molecule. This has led to major strides in the understanding of the function of bromodomain-containing proteins and their involvement in diseases such as cancer and inflammation. Indeed, BET bromodomain inhibitors are now being clinically evaluated for the treatment of hematological tumors and have also been tested in clinical trials for the relatively rare BRD-NUT midline carcinoma. This review gives an overview of the newest developments in the field, with a focus on the biology of selected bromodomain proteins on the one hand, and on reported pharmacological inhibitors on the other, including recent examples from the patent literature. PMID:24497428

  6. Enhancing CHK1 inhibitor lethality in glioblastoma.

    PubMed

    Tang, Yong; Dai, Yun; Grant, Steven; Dent, Paul

    2012-04-01

    The present studies were initiated to determine whether inhibitors of MEK1/2 or SRC signaling, respectively, enhance CHK1 inhibitor lethality in primary human glioblastoma cells. Multiple MEK1/2 inhibitors (CI-1040 (PD184352); AZD6244 (ARRY-142886)) interacted with multiple CHK1 inhibitors (UCN-01, AZD7762) to kill multiple primary human glioma cell isolates that have a diverse set of genetic alterations typically found in the disease. Inhibition of SRC family proteins also enhanced CHK1 inhibitor lethality. Combined treatment of glioma cells with (MEK1/2 + CHK1) inhibitors enhanced radiosensitivity. Combined (MEK1/2 + CHK1) inhibitor treatment led to dephosphorylation of ERK1/2 and S6 ribosomal protein, whereas the phosphorylation of JNK and p38 was increased. MEK1/2 + CHK1 inhibitor-stimulated cell death was associated with the cleavage of pro-caspases 3 and 7 as well as the caspase substrate (PARP). We also observed activation of pro-apoptotic BCL-2 effector proteins BAK and BAX and reduced levels of pro-survival BCL-2 family protein BCL-XL. Overexpression of BCL-XL alleviated but did not completely abolish MEK1/2 + CHK1 inhibitor cytotoxicity in GBM cells. These findings argue that multiple inhibitors of the SRC-MEK pathway have the potential to interact with multiple CHK1 inhibitors to kill glioma cells. PMID:22313687

  7. The burden of inhibitors in haemophilia patients.

    PubMed

    Walsh, Christopher E; Jiménez-Yuste, Víctor; Auerswald, Guenter; Grancha, Salvador

    2016-08-31

    The burden of disease in haemophilia patients has wide ranging implications for the family and to society. There is evidence that having a current inhibitor increases the risk of morbidity and mortality. Morbidity is increased by the inability to treat adequately and its consequent disabilities, which then equates to a poor quality of life compared with non-inhibitor patients. The societal cost of care, or `burden of inhibitors', increases with the ongoing presence of an inhibitor. Therefore, it is clear that successful eradication of inhibitors by immune tolerance induction (ITI) is the single most important milestone one can achieve in an inhibitor patient. The type of factor VIII (FVIII) product used in ITI regimens varies worldwide. Despite ongoing debate, there is in vitro and retrospective clinical evidence to support the use of plasma-derived VWF-containing FVIII concentrates in ITI regimens in order to achieve early and high inhibitor eradication success rates. PMID:27528280

  8. Xylanase inhibitors bind to nonstarch polysaccharides.

    PubMed

    Fierens, Ellen; Gebruers, Kurt; Courtin, Christophe M; Delcour, Jan A

    2008-01-23

    This study is an in-depth investigation of the interaction between polysaccharides and the proteinaceous xylanase inhibitors, Triticum aestivum xylanase inhibitor (TAXI), xylanase inhibitor protein (XIP), and thaumatin-like xylanase inhibitor (TLXI). The binding affinities of all three known types of xylanase inhibitors from wheat are studied by measuring the residual xylanase inhibition activity after incubation of the inhibitors in the presence of different polysaccharides, such as beta-glucans and (arabino)xylans. The binding affinities of all three xylanase inhibitors for (arabino)xylans increased with a decreasing arabinose/xylose ratio (A/X ratio). This phenomenon was observed both with water-extractable and water-unextractable (arabino)xylans. The inhibitors also interacted with different soluble and insoluble beta-glucans. None of the inhibitors tested had the ability to hydrolyze the polysaccharides investigated. The present findings contribute to the unraveling of the function of xylanase inhibitors in nature and to the prediction of the effect of added xylanases in cereal-based biotechnological processes, such as bread making and gluten-starch separation. PMID:18092758

  9. Biomarkers associated with checkpoint inhibitors.

    PubMed

    Manson, G; Norwood, J; Marabelle, A; Kohrt, H; Houot, R

    2016-07-01

    Checkpoint inhibitors (CPI), namely anti-CTLA4 and anti-PD1/PD-L1 antibodies, demonstrated efficacy across multiple types of cancer. However, only subgroups of patients respond to these therapies. Additionally, CPI can induce severe immune-related adverse events (irAE). Biomarkers that predict efficacy and toxicity may help define the patients who may benefit the most from these costly and potentially toxic therapies. In this study, we review the main biomarkers that have been associated with the efficacy (pharmacodynamics and clinical benefit) and the toxicity (irAE) of CPIs in patients. PMID:27122549

  10. Monoamine Oxidase Inhibitors: Clinical Review

    PubMed Central

    Remick, Ronald A.; Froese, Colleen

    1990-01-01

    Monoamine oxidase inhibitors (MAOIs) are effective antidepressant agents. They are increasingly and effectively used in a number of other psychiatric and non-psychiatric medical syndromes. Their potential for serious toxicity (i.e., hypertensive reaction) is far less than original reports suggest, and newer reversible substrate-specific MAOIs may offer even less toxicity. The author reviews the pharmacology, mechanism of action, clinical indications, and dosing strategies of MAOIs. The common MAOI side-effects (hypotension, weight gain, sexual dysfunction, insomnia, daytime sedation, myoclonus, and hypertensive episodes) are described and management techniques suggested. Recent clinical developments involving MAOIs are outlined. PMID:21233984

  11. Oligopeptide cyclophilin inhibitors: a reassessment.

    PubMed

    Schumann, Michael; Jahreis, Günther; Kahlert, Viktoria; Lücke, Christian; Fischer, Gunter

    2011-11-01

    Potent cyclophilin A (CypA) inhibitors such as non-immunosuppressive cyclosporin A (CsA) derivatives have been already used in clinical trials in patients with viral infections. CypA is a peptidyl prolyl cis/trans isomerase (PPIase) that catalyzes slow prolyl bond cis/trans interconversions of the backbone of substrate peptides and proteins. In this study we investigate whether the notoriously low affinity inhibitory interaction of linear proline-containing peptides with the active site of CypA can be increased through a combination of a high cis/trans ratio and a negatively charged C-terminus as has been recently reported for Trp-Gly-Pro. Surprisingly, isothermal titration calorimetry did not reveal formation of an inhibitory CypA/Trp-Gly-Pro complex previously described within a complex stability range similar to CsA, a nanomolar CypA inhibitor. Moreover, despite of cis content of 41% at pH 7.5 Trp-Gly-Pro cannot inhibit CypA-catalyzed standard substrate isomerization up to high micromolar concentrations. However, in the context of the CsA framework a net charge of -7 clustered at the amino acid side chain of position 1 resulted in slightly improved CypA inhibition. PMID:21963115

  12. New proteasome inhibitors in myeloma.

    PubMed

    Lawasut, Panisinee; Chauhan, Dharminder; Laubach, Jacob; Hayes, Catriona; Fabre, Claire; Maglio, Michelle; Mitsiades, Constantine; Hideshima, Teru; Anderson, Kenneth C; Richardson, Paul G

    2012-12-01

    Proteasome inhibition has a validated role in cancer therapy since the successful introduction of bortezomib for the treatment of multiple myeloma (MM) and mantle cell lymphoma, leading to the development of second-generation proteasome inhibitors (PI) for MM patients in whom currently approved therapies have failed. Five PIs have reached clinical evaluation, with the goals of improving efficacy and limiting toxicity, including peripheral neuropathy (PN). Carfilzomib, an epoxyketone with specific chymothrypsin-like activity, acts as an irreversible inhibitor and was recently FDA approved for the response benefit seen in relapsed and refractory MM patients previously treated with bortezomib, thalidomide and lenalidomide. ONX-0912 is now under evaluation as an oral form with similar activity. The boronate peptides MLN9708 and CEP-18770 are orally bioactive bortezomib analogs with prolonged activity and greater tissue penetration. NPI-0052 (marizomib) is a unique, beta-lactone non-selective PI that has been shown to potently overcome bortezomib resistance in vitro. All of these second-generation PIs demonstrate encouraging anti-MM activity and appear to reduce the incidence of PN, with clinical trials ongoing. PMID:23065395

  13. New sulfur-containing corrosion inhibitor

    SciTech Connect

    Prince, P.

    2000-04-01

    No corrosion inhibitor available today is ideal in every way, but a new class of sulfur-containing compounds promises to address many field requirements. This article describes the performance characteristics of these compounds and discusses possible inhibition mechanisms. The emphasis in this work was on better understanding corrosion inhibition by sulfur-containing inhibitors under high shear-stress conditions, with special focus on localized (pitting) corrosion. The results indicate that the new sulfur-containing inhibitors (e.g., mercaptoalcohol [MA]) could be more effective in the field than currently available inhibitors.

  14. Simultaneous exposure of transformed cells to SRC family inhibitors and CHK1 inhibitors causes cell death.

    PubMed

    Mitchell, Clint; Hamed, Hossein A; Cruickshanks, Nichola; Tang, Yong; Bareford, M Danielle; Hubbard, Nissan; Tye, Gary; Yacoub, Adly; Dai, Yun; Grant, Steven; Dent, Paul

    2011-08-01

    The present studies were initiated to determine in greater molecular detail the regulation of CHK1 inhibitor lethality in transfected and infected breast cancer cells and using genetic models of transformed fibrobalsts. Multiple MEK1/2 inhibitors (PD184352, AZD6244 (ARRY-142886)) interacted with multiple CHK1 inhibitors (UCN-01 (7-hydroxystaurosporine), AZD7762) to kill mammary carcinoma cells and transformed fibroblasts. In transformed cells, CHK1 inhibitor -induced activation of ERK1/2 was dependent upon activation of SRC family non-receptor tyrosine kinases as judged by use of multiple SRC kinase inhibitors (PP2, Dasatinib; AZD0530), use of SRC/FYN/YES deleted transformed fibroblasts or by expression of dominant negative SRC. Cell killing by SRC family kinase inhibitors and CHK1 inhibitors was abolished in BAX/BAK -/- transformed fibroblasts and suppressed by over expression of BCL-XL. Treatment of cells with BCL-2/BCL-XL antagonists promoted SRC inhibitor + CHK1 inhibitor -induced lethality in a BAX/BAK-dependent fashion. Treatment of cells with [SRC + CHK1] inhibitors radio-sensitized tumor cells. These findings argue that multiple inhibitors of the SRC-RAS-MEK pathway interact with multiple CHK1 inhibitors to kill transformed cells. PMID:21642769

  15. Controlling CO{sub 2} corrosion with inhibitors

    SciTech Connect

    Dougherty, J.A.

    1998-12-31

    Transport of corrosion inhibitor to the location where they are needed is one of the primary concerns in the use of corrosion inhibitors. Two different types of inhibitors for controlling CO{sub 2} corrosion in gas well wellheads and flowlines are used as examples. In one example, the inhibitor forms a micelle in water which assists in the transport of inhibitor to the metal surface . In the other example, the inhibitor is readily dispersible in the water phase but must be stirred to ensure transport of the inhibitor to the metal surface. Field monitored corrosion rates using continuous application of inhibitor are presented for both types of inhibitor.

  16. Glycine Transporters and Their Inhibitors

    NASA Astrophysics Data System (ADS)

    Gilfillan, Robert; Kerr, Jennifer; Walker, Glenn; Wishart, Grant

    Glycine plays a ubiquitous role in many biological processes. In the central nervous system it serves as an important neurotransmitter acting as an agonist at strychnine-sensitive glycine receptors and as an essential co-agonist with glutamate at the NMDA receptor complex. Control of glycine concentrations in the vicinity of these receptors is mediated by the specific glycine transporters, GlyT1 and GlyT2. Inhibition of these transporters has been postulated to be of potential benefit in several therapeutic indications including schizophrenia and pain. In this review we discuss our current knowledge of glycine transporters and focus on recent advances in the medicinal chemistry of GlyT1 and GlyT2 inhibitors.

  17. KH-30 Parafin Inhibitor Treatment

    SciTech Connect

    Rochelle, J.

    2001-09-30

    United Energy Corporation (UNRG) and the U.S. Department of Energy personnel tested KH-30 at the Rocky Mountain Oilfield Testing Center (RMOTC) outside Casper, Wyoming on two separate occasions. KH-30 is a non-toxic, non-hazardous product, which combines the functions of a solvent dispersant, crystal modifier and inhibitor into a single solution. The first test was held in March of 2001, wherein five wells were treated with a mixture of KH-30 and brine water, heated to 180 degrees F. No increase in production was attained in these tests. In June, 2001, three shallow, low pressure RMOTC wells with 30 years of production were treated with a mixture of 40% KH-30 and 60% diesel. Increases were seen in three wells. The wells then returned to their original rates.

  18. Natural Products as Aromatase Inhibitors

    PubMed Central

    Balunas, Marcy J.; Su, Bin; Brueggemeier, Robert W.; Kinghorn, A. Douglas

    2010-01-01

    With the clinical success of several synthetic aromatase inhibitors (AIs) in the treatment of postmenopausal estrogen receptor-positive breast cancer, researchers have also been investigating also the potential of natural products as AIs. Natural products from terrestrial and marine organisms provide a chemically diverse array of compounds not always available through current synthetic chemistry techniques. Natural products that have been used traditionally for nutritional or medicinal purposes (e.g., botanical dietary supplements) may also afford AIs with reduced side effects. A thorough review of the literature regarding natural product extracts and secondary metabolites of plant, microbial, and marine origin that have been shown to exhibit aromatase inhibitory activity is presented herein. PMID:18690828

  19. Loratadine analogues as MAGL inhibitors.

    PubMed

    Patel, Jayendra Z; Ahenkorah, Stephen; Vaara, Miia; Staszewski, Marek; Adams, Yahaya; Laitinen, Tuomo; Navia-Paldanius, Dina; Parkkari, Teija; Savinainen, Juha R; Walczyński, Krzysztof; Laitinen, Jarmo T; Nevalainen, Tapio J

    2015-04-01

    Compound 12a (JZP-361) acted as a potent and reversible inhibitor of human recombinant MAGL (hMAGL, IC50=46 nM), and was found to have almost 150-fold higher selectivity over human recombinant fatty acid amide hydrolase (hFAAH, IC50=7.24 μM) and 35-fold higher selectivity over human α/β-hydrolase-6 (hABHD6, IC50=1.79 μM). Additionally, compound 12a retained H1 antagonistic affinity (pA2=6.81) but did not show cannabinoid receptor activity, when tested at concentrations ⩽ 10 μM. Hence, compound 12a represents a novel dual-acting pharmacological tool possessing both MAGL-inhibitory and antihistaminergic activities. PMID:25752982

  20. Inhibitors of apoptosis catch ubiquitin.

    PubMed

    Rajalingam, Krishnaraj; Dikic, Ivan

    2009-01-01

    IAP (inhibitor of apoptosis) proteins are a class of anti-apoptotic regulators characterized by the presence of BIR (baculoviral IAP repeat) domains. Some of the IAPs also possess a RING (really interesting new gene) domain with E3 ubiquitin ligase activity. In this issue of the Biochemical Journal, Blankenship et al. unveil the presence of an UBA (ubiquitin-associated domain) in several IAPs. UBAs in c-IAPs (cellular IAPs) bind to monoubiquitin and ubiquitin chains and are implicated in degradation of c-IAPs by promoting their interaction with proteasomes as well as in regulation of TNF-alpha (tumour necrosis factor-alpha)-induced apoptosis. These novel observations establish IAPs as ubiquitin-interacting proteins and opens up new lines of investigation. PMID:19061481

  1. Quinolone-based HDAC inhibitors.

    PubMed

    Balasubramanian, Gopalan; Kilambi, Narasimhan; Rathinasamy, Suresh; Rajendran, Praveen; Narayanan, Shridhar; Rajagopal, Sridharan

    2014-08-01

    HDAC inhibitors emerged as promising drug candidates in combating wide variety of cancers. At present, two of the compounds SAHA and Romidepsin were approved by FDA for cutaneous T-cell lymphoma and many are in various clinical phases. A new quinolone cap structure was explored with hydroxamic acid as zinc-binding group (ZBG). The pan HDAC inhibitory and antiproliferative activities against three human cancer cell lines HCT-116 (colon), NCI-H460 (lung) and U251 (glioblastoma) of the compounds (4a-4w) were evaluated. Introduction of heterocyclic amines in CAP region increased the enzyme inhibitory and antiproliferative activities and few of the compounds tested are metabolically stable in both MLM and HLM. PMID:25019596

  2. The direct thrombin inhibitor hirudin.

    PubMed

    Greinacher, Andreas; Warkentin, Theodore E

    2008-05-01

    This review discusses the pharmacology and clinical applications of hirudin, a bivalent direct thrombin inhibitor (DTI). Besides the current major indication for hirudin--anticoagulation of patients with heparin-induced thrombocytopenia (HIT)--the experience with hirudin in other indications, especially acute coronary syndromes, are briefly presented. Hirudins have been formally studied prior to their regulatory approval; however, important information on their side effects and relevant preventative measures only became available later. Therefore, current recommendations and dosing schedules for hirudin differ considerably from the information given in the package inserts. Drawbacks of hirudin and important precautions for avoiding potential adverse effects are discussed in detail in the third part of this review. PMID:18449411

  3. Enzyme-Inhibitor Association Thermodynamics

    PubMed Central

    Resat, Haluk; Marrone, Tami J.; McCammon, J. Andrew

    1997-01-01

    Studying the thermodynamics of biochemical association reactions at the microscopic level requires efficient sampling of the configurations of the reactants and solvent as a function of the reaction pathways. In most cases, the associating ligand and receptor have complementary interlocking shapes. Upon association, loosely connected or disconnected solvent cavities at and around the binding site are formed. Disconnected solvent regions lead to severe statistical sampling problems when simulations are performed with explicit solvent. It was recently proposed that, when such limitations are encountered, they might be overcome by the use of the grand canonical ensemble. Here we investigate one such case and report the association free energy profile (potential of mean force) between trypsin and benzamidine along a chosen reaction coordinate as calculated using the grand canonical Monte Carlo method. The free energy profile is also calculated for a continuum solvent model using the Poisson equation, and the results are compared to the explicit water simulations. The comparison shows that the continuum solvent approach is surprisingly successful in reproducing the explicit solvent simulation results. The Monte Carlo results are analyzed in detail with respect to solvation structure. In the binding site channel there are waters bridging the carbonyl oxygen groups of Asp189 with the NH2 groups of benzamidine, which are displaced upon inhibitor binding. A similar solvent-bridging configuration has been seen in the crystal structure of trypsin complexed with bovine pancreatic trypsin inhibitor. The predicted locations of other internal waters are in very good agreement with the positions found in the crystal structures, which supports the accuracy of the simulations. ImagesFIGURE 5 PMID:9017183

  4. Intellectual property issues of immune checkpoint inhibitors.

    PubMed

    Storz, Ulrich

    2016-01-01

    Immune checkpoint inhibitors are drugs that interfere with tumor escape responses. Some members of this class are already approved, and expected to be blockbusters in the future. Many companies have developed patent activities in this field. This article focuses on the patent landscape, and discusses key players and cases related to immune checkpoint inhibitors. PMID:26466763

  5. Trypsin inhibitors for the treatment of pancreatitis.

    PubMed

    Brandl, Trixi; Simic, Oliver; Skaanderup, Philip R; Namoto, Kenji; Berst, Frederic; Ehrhardt, Claus; Schiering, Nikolaus; Mueller, Irene; Woelcke, Julian

    2016-09-01

    Proline-based trypsin inhibitors occupying the S1-S2-S1' region were identified by an HTS screening campaign. It was discovered that truncation of the P1' moiety and appropriate extension into the S4 region led to highly potent trypsin inhibitors with excellent selectivity against related serine proteases and a favorable hERG profile. PMID:27476144

  6. Aminofurazans as potent inhibitors of AKT kinase

    SciTech Connect

    Rouse, Meagan B.; Seefeld, Mark A.; Leber, Jack D.; McNulty, Kenneth C.; Sun, Lihui; Miller, William H.; Zhang, ShuYun; Minthorn, Elisabeth A.; Concha, Nestor O.; Choudhry, Anthony E.; Schaber, Michael D.; Heerding, Dirk A.

    2009-06-24

    AKT inhibitors containing an imidazopyridine aminofurazan scaffold have been optimized. We have previously disclosed identification of the AKT inhibitor GSK690693, which has been evaluated in clinical trials in cancer patients. Herein we describe recent efforts focusing on investigating a distinct region of this scaffold that have afforded compounds (30 and 32) with comparable activity profiles to that of GSK690693.

  7. Discovery and SAR of hydantoin TACE inhibitors

    SciTech Connect

    Yu, Wensheng; Guo, Zhuyan; Orth, Peter; Madison, Vincent; Chen, Lei; Dai, Chaoyang; Feltz, Robert J.; Girijavallabhan, Vinay M.; Kim, Seong Heon; Kozlowski, Joseph A.; Lavey, Brian J.; Li, Dansu; Lundell, Daniel; Niu, Xiaoda; Piwinski, John J.; Popovici-Muller, Janeta; Rizvi, Razia; Rosner, Kristin E.; Shankar, Bandarpalle B.; Shih, Neng-Yang; Siddiqui, M.A.; Sun, J.; Tong, L.; Umland, S.; Wong, M.K.; Yang, D.Y.; Zhou, G.

    2010-09-03

    We disclose inhibitors of TNF-{alpha} converting enzyme (TACE) designed around a hydantoin zinc binding moiety. Crystal structures of inhibitors bound to TACE revealed monodentate coordination of the hydantoin to the zinc. SAR, X-ray, and modeling designs are described. To our knowledge, these are the first reported X-ray structures of TACE with a hydantoin zinc ligand.

  8. Tyrosinase inhibitors from Bolivian medicinal plants.

    PubMed

    Kubo, I; Yokokawa, Y; Kinst-Hori, I

    1995-05-01

    Bioassay-guided fractionation monitored by mushroom tyrosinase (EC 1.14.18.1) activity, afforded six inhibitors from three Bolivian medicinal plants, Buddleia coriacea, Gnaphalium cheiranthifolium, and Scheelea princeps. These inhibitors, which are all known phenolic compounds, inhibited the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) mediated by a mushroom tyrosinase. PMID:7623048

  9. The therapeutic potential of microbial proteasome inhibitors.

    PubMed

    Momose, Isao; Kawada, Manabu

    2016-08-01

    The proteasome influences cellular homeostasis through the degradation of regulatory proteins, many of which are also involved in disease pathogenesis. In particular, numerous regulatory proteins associated with tumor growth, such as cyclins, cyclin-dependent kinase inhibitors, tumor suppressors, and NF-κB inhibitors are degraded by the proteasome. Proteasome inhibitors can stabilize these regulatory proteins, resulting in the suppression of tumor development and the regulation of immune responses. Thus, proteasome inhibitors are promising candidate antitumor agents and immune-regulatory agents. Bortezomib is the first-in-class proteasome inhibitor approved for the treatment of multiple myeloma. Despite its high efficiency, however, a large proportion of patients do not attain sufficient clinical response due to toxicity and drug resistance. Therefore, the development of new proteasome inhibitors with improved pharmacological properties is needed. Natural products produced by microorganisms are a promising source of such compounds. This review provides an overview of proteasome inhibitors produced by microorganisms, with special focus on inhibitors isolated from actinomycetes. PMID:26589840

  10. [Recent development of selective cyclooxygenase-2 inhibitors].

    PubMed

    Kawai, Shinichi

    2002-12-01

    Nonsteroidal anti-inflammatory drugs(NSAIDs) are clinically effective against the inflammatory symptoms of rheumatoid arthritis. Recent attention has been focused on selective cyclooxygenase(COX)-2 inhibitors, a type of NSAID that inhibits a subtype of COX. Because of the different actions of COX-1 and COX-2, selective COX-2 inhibitors were expected to reduce adverse reactions such as gastrointestinal disorders. Various clinical studies have confirmed that the efficacy of COX-2 inhibitors for RA is similar to that of conventional NSAIDs, but they cause fewer severe gastrointestinal disorders. The incidence of complications related to renal dysfunction, such as edema and hypertension, is not different. Patients using selective COX-2 inhibitors have recently been reported to show an increase in thrombotic complications such as myocardial infarction. Therefore, more data on adverse events should be collected in the future from large-scale clinical studies to further clarify the actual value of selective COX-2 inhibitors. PMID:12510364

  11. Current acetylcholinesterase-inhibitors: a neuroinformatics perspective.

    PubMed

    Shaikh, Sibhghatulla; Verma, Anupriya; Siddiqui, Saimeen; Ahmad, Syed S; Rizvi, Syed M D; Shakil, Shazi; Biswas, Deboshree; Singh, Divya; Siddiqui, Mohmmad H; Shakil, Shahnawaz; Tabrez, Shams; Kamal, Mohammad A

    2014-04-01

    This review presents a concise update on the inhibitors of the neuroenzyme, acetylcholinesterase (AChE; EC 3.1.1.7). AChE is a serine protease, which hydrolyses the neurotransmitter, acetylcholine into acetate and choline thereby terminating neurotransmission. Molecular interactions (mode of binding to the target enzyme), clinical applications and limitations have been summarized for each of the inhibitors discussed. Traditional inhibitors (e.g. physostigmine, tacrine, donepezil, rivastigmine etc.) as well as novel inhibitors like various physostigmine-derivatives have been covered. This is followed by a short glimpse on inhibitors derived from nature (e.g. Huperzine A and B, Galangin). Also, a discussion on 'hybrid of pre-existing drugs' has been incorporated. Furthermore, current status of therapeutic applications of AChEinhibitors has also been summarized. PMID:24059296

  12. Pharmacological inhibitors of cyclin-dependent kinases.

    PubMed

    Knockaert, Marie; Greengard, Paul; Meijer, Laurent

    2002-09-01

    Cyclin-dependent kinases (CDKs) regulate the cell division cycle, apoptosis, transcription and differentiation in addition to functions in the nervous system. Deregulation of CDKs in various diseases has stimulated an intensive search for selective pharmacological inhibitors of these kinases. More than 50 inhibitors have been identified, among which >20 have been co-crystallized with CDK2. These inhibitors all target the ATP-binding pocket of the catalytic site of the kinase. The actual selectivity of most known CDK inhibitors, and thus the underlying mechanism of their cellular effects, is poorly known. Pharmacological inhibitors of CDKs are currently being evaluated for therapeutic use against cancer, alopecia, neurodegenerative disorders (e.g. Alzheimer's disease, amyotrophic lateral sclerosis and stroke), cardiovascular disorders (e.g. atherosclerosis and restenosis), glomerulonephritis, viral infections (e.g. HCMV, HIV and HSV) and parasitic protozoa (Plasmodium sp. and Leishmania sp.). PMID:12237154

  13. High-affinity Cyclic Peptide Matriptase Inhibitors*

    PubMed Central

    Quimbar, Pedro; Malik, Uru; Sommerhoff, Christian P.; Kaas, Quentin; Chan, Lai Y.; Huang, Yen-Hua; Grundhuber, Maresa; Dunse, Kerry; Craik, David J.; Anderson, Marilyn A.; Daly, Norelle L.

    2013-01-01

    The type II transmembrane serine protease matriptase is a key activator of multiple signaling pathways associated with cell proliferation and modification of the extracellular matrix. Deregulated matriptase activity correlates with a number of diseases, including cancer and hence highly selective matriptase inhibitors may have therapeutic potential. The plant-derived cyclic peptide, sunflower trypsin inhibitor-1 (SFTI-1), is a promising drug scaffold with potent matriptase inhibitory activity. In the current study we have analyzed the structure-activity relationships of SFTI-1 and Momordica cochinchinensis trypsin inhibitor-II (MCoTI-II), a structurally divergent trypsin inhibitor from Momordica cochinchinensis that also contains a cyclic backbone. We show that MCoTI-II is a significantly more potent matriptase inhibitor than SFTI-1 and that all alanine mutants of both peptides, generated using positional scanning mutagenesis, have decreased trypsin affinity, whereas several mutations either maintain or result in enhanced matriptase inhibitory activity. These intriguing results were used to design one of the most potent matriptase inhibitors known to date with a 290 pm equilibrium dissociation constant, and provide the first indication on how to modulate affinity for matriptase over trypsin in cyclic peptides. This information might be useful for the design of more selective and therapeutically relevant inhibitors of matriptase. PMID:23548907

  14. Current use of phosphodiesterase inhibitors in urology

    PubMed Central

    Hakky, Tariq Said; Jain, Lakshay

    2015-01-01

    The causes of male erectile dysfunction (ED) are quite variable and are now commonly divided into etiologies such as ischemia, smooth muscle damage, or altered blood flow. Although varying rates of ED have been reported in literature, the number of men with ED is projected to increase worldwide by 2025 to approximately 322 million. Since the introduction of phosphodiesterase 5 (PDE5) inhibitors, there has been a paradigm shift in the treatment of ED because PDE5 inhibitors address a broad spectrum of etiologies for ED. Today, the American Urological Association recommends the use of three PDE5 inhibitors (sildenafil, tadalafil, and vardenafil) as a first-line therapy for the treatment of ED. This review evaluates the pharmacological mechanism of PDE5 inhibitors along with the impact and use of sildenafil, vardenafil, tadalafil, and avanafil. By increasing intracellular cGMP levels, PDE5 inhibitors have been shown to be effective in the treatment of ED. Through their effects on other cellular signaling pathways, PDE5 inhibitors have the potential for treating other urologic conditions as well. The use of PDE5 inhibitors can also be combined to produce a synergistic effect in conditions such as male hypogonadism and benign prostatic hyperplasia in addition to ED. PMID:26328208

  15. Multi-kinase inhibitors, AURKs and cancer.

    PubMed

    Cicenas, Jonas; Cicenas, Erikas

    2016-05-01

    Inhibitors that impact function of kinases are valuable both for the biological research as well as therapy of kinase-associated diseases, such as different cancers. There are quite a number of inhibitors, which are quite specific for certain kinases and several of them are either already approved for the cancer therapy or are in clinical studies of various phases. However, that does not mean that each single kinase inhibitor is suitable for targeted therapy. Some of them are not effective others might be toxic or fail some other criteria for the use in vivo. On the other hand, even in case of successful therapy, many responders eventually develop resistance to the inhibitors. The limitations of various single kinase inhibitors can be fought using compounds which target multiple kinases. This tactics can increase effectiveness of the inhibitors by the synergistic effect or help to diminish the likelihood of drug resistance. To date, several families of kinases are quite popular targets of the inhibition in cancers, such as tyrosine kinases, cycle-dependent kinases, mitogen-activated protein kinases, phosphoinositide 3-kinases as well as their pathway "players" and aurora kinases. Aurora kinases play an important role in the control of the mitosis and are often altered in diverse human cancers. Here, we will describe the most interesting multi-kinase inhibitors which inhibit aurora kinases among other targets and their use in preclinical and clinical cancer studies. PMID:27038473

  16. Interaction of Chloroplasts with Inhibitors

    PubMed Central

    Ridley, Stuart M.

    1983-01-01

    Several effects on pea (Pisum sativum L. var Onwards) chloroplasts of a new diphenylether herbicide, fomesafen (5-[2-chloro-4-trifluoromethyl-phenoxy]-N-methanesulfonyl-2 -nitrobenzamide) have been compared with those of a herbicide of related structure, nitrofluorfen (2-chloro-1-[4-nitrophenoxy]-4-[trifluoromethyl]benzene). Although both compounds produce the same light-dependent symptoms of desiccation and chlorosis indicative of a common primary mechanism of action, this study is concerned with a more broadly based investigation of different effects on the electron transport system. Comparisons have also been made with other compounds interacting with the chloroplast. Unlike nitrofluorfen, fomesafen has little effect as an inhibitor of electron flow or energy transfer. Both compounds have the ability to stimulate superoxide production through a functional electron transport system, and this involves specifically the p-nitro substituent. The stimulation, which is not likely to be an essential part of the primary herbicidal effect, is diminished under conditions that remove the coupling factor. Evidence suggests that both diphenylethers may be able to bind to the coupling factor, and kinetic studies reveal this for dibromothymoquinone as well. Such a binding site might be an important feature in allowing the primary effect of the diphenylether herbicides to be expressed. PMID:16663025

  17. Reverse transcriptase inhibitors as microbicides.

    PubMed

    Lewi, Paul; Heeres, Jan; Ariën, Kevin; Venkatraj, Muthusamy; Joossens, Jurgen; Van der Veken, Pieter; Augustyns, Koen; Vanham, Guido

    2012-01-01

    The CAPRISA 004 study in South Africa has accelerated the development of vaginal and rectal microbicides containing antiretrovirals that target specific enzymes in the reproduction cycle of HIV, especially reverse transcriptase inhibitors (RTI). In this review we discuss the potential relevance of HIV-1 RTIs as microbicides, focusing in the nucleotide RTI tenofovir and six classes of nonnucleoside RTIs (including dapivirine, UC781, urea and thiourea PETTs, DABOs and a pyrimidinedione). Although tenofovir and dapivirine appear to be most advanced in clinical trials as potential microbicides, several issues remain unresolved, e.g., the importance of nonhuman primates as a "gatekeeper" for clinical trials, the emergence and spread of drug-resistant mutants, the combination of microbicides that target different phases of viral reproduction and the accessibility to microbicides in low-income countries. Thus, here we discuss the latest research on RTI as microbicides in the light of the continuing spread of the HIV pandemic from the point of view of medicinal chemistry, virological, and pharmaceutical studies. PMID:22264043

  18. Increased inhibitor incidence in severe haemophilia A since 1990 attributable to more low titre inhibitors.

    PubMed

    van den Berg, H Marijke; Hashemi, S Mojtaba; Fischer, Kathelijn; Petrini, Pia; Ljung, Rolf; Rafowicz, Anne; Carcao, Manuel; Auerswald, Günter; Kurnik, Karin; Kenet, Gili; Santagostino, Elena

    2016-04-01

    Many studies have reported an increased incidence of inhibitors in previously untreated patients (PUPs) with severe haemophilia A after the introduction of recombinant products. It was the objective of this study to investigate whether the inhibitor incidence has increased between 1990 and 2009 in an unselected cohort of PUPs with severe haemophilia A (FVIII< 1 %). Patients were consecutively recruited from 31 haemophilia treatment centres in 16 countries and followed until 50 exposure days or until inhibitor development. Inhibitor development was studied in five-year birth cohorts comparing cumulative incidences. Furthermore the risk for inhibitor development per five-year birth cohort was studied using multivariable Cox regression, adjusting for potential genetic and treatment-related confounders. A total of 926 PUPs were included with a total cumulative inhibitor incidence of 27.5 %. The inhibitor incidence increased from 19.5 % in 1990-1994 (lowest) to 30.9 % in 2000-2004 (highest; p-value 0.011). Low titre inhibitor incidence increased from 3.1 % in 1990-1994 to 10.5 % in 2005-2009 (p-value 0.009). High titre inhibitor incidences remained stable over time. After 2000, risk of all inhibitor development was increased with adjusted hazard ratios 1.96 (95 % CI 1.06-2.83) in 2000-2004 and 2.34 (1.42-4.92) in 2005-2009. Screening for inhibitors was intensified over this 20-year study period from a median of 1.9 to 2.9 tests/year before 2000 to 2.7 to 4.3 tests/year after 2000. In conclusion, the cumulative inhibitor incidence has significantly increased between 1990 and 2009. The high titre inhibitor incidence has remained stable. PMID:26632988

  19. An Updated Review of Tyrosinase Inhibitors

    PubMed Central

    Chang, Te-Sheng

    2009-01-01

    Tyrosinase is a multifunctional, glycosylated, and copper-containing oxidase, which catalyzes the first two steps in mammalian melanogenesis and is responsible for enzymatic browning reactions in damaged fruits during post-harvest handling and processing. Neither hyperpigmentation in human skin nor enzymatic browning in fruits are desirable. These phenomena have encouraged researchers to seek new potent tyrosinase inhibitors for use in foods and cosmetics. This article surveys tyrosinase inhibitors newly discovered from natural and synthetic sources. The inhibitory strength is compared with that of a standard inhibitor, kojic acid, and their inhibitory mechanisms are discussed. PMID:19582213

  20. Migrating corrosion inhibitor protection of concrete

    SciTech Connect

    Bjegovic, D.; Miksic, B.

    1999-11-01

    Migrating corrosion inhibitors (MCI) were developed to protect steel rebar from corrosion in concrete. They were designed to be incorporated as an admixture during concrete batching or used for surface impregnation of existing concrete structures. Two investigations are summarized. One studied the effectiveness of MCIs as a corrosion inhibitor for steel rebar when used as an admixture in fresh concrete mix. The other is a long-term study of MCI concrete impregnation that chronicles corrosion rates of rebar in concrete specimens. Based on data from each study, it was concluded that migrating corrosion inhibitors are compatible with concrete and effectively delay the onset of corrosion.

  1. In vitro and in vivo characterisation of the profibrinolytic effect of an inhibitory anti-rat TAFI nanobody.

    PubMed

    Hendrickx, Maarten L V; Zatloukalova, Monika; Hassanzadeh-Ghassabeh, Gholamreza; Muyldermans, Serge; Gils, Ann; Declerck, Paul J

    2014-05-01

    One of the main disadvantages of current t-PA thrombolytic treatment is the increased bleeding risk. Upon activation, thrombin activatable fibrinolysis inhibitor (TAFI) is a very powerful antifibrinolytic enzyme. Therefore, co-administration of a TAFI inhibitor during thrombolysis could reduce the required t-PA dose without compromising the thrombolytic efficacy. In this study we generated and characterised a nanobody that is inhibitory towards rat TAFI and evaluated its profibrinolytic property in vitro and in vivo. Nanobody VHH-rTAFI-i81 inhibits (at a 16-fold molar ratio nanobody over TAFI) the thrombin/thrombomodulin (T/TM)-mediated activation of rat TAFI (rTAFI) by 83 ± 1.8% with an IC50 of 0.46 (molar ratio nanobody over TAFI). The affinity (KA) of VHH-rTAFI-i81 for rTAFI, as determined by surface plasmon resonance (Biacore®), is 2.5 ± 0.2 x 10(10) M(-1) and illustrates a very strong binding. In an in vitro clot lysis assay, administration of VHH-rTAFI-i81 strongly enhances the degree of lysis and reduces time to reach full lysis of t-PA-mediated clot lysis. Epitope mapping discloses that Lys392 is of primary importance for the nanobody/rTAFI interaction besides minor contributions of Tyr175 and Glu183. In vivo application of VHH-rTAFI-i81 in a tissue factor-induced mouse thromboembolism model significantly decreases fibrin deposition in the lungs in the absence of exogenous administered t-PA. Nanobody VHH-rTAFI-i81 is a very potent inhibitor of T/TM-mediated TAFI activation. Co-administration of this nanobody and t-PA enhances the fibrinolytic efficacy. In an in vivo mouse thromboembolism model, VHH-rTAFI-i81 reduces fibrin deposition in the lungs. PMID:24402608

  2. Is There a Tendency for Thrombosis in Gestational Diabetes Mellitus?

    PubMed Central

    Gorar, Suheyla; Alioglu, Bulent; Ademoglu, Esranur; Uyar, Seyit; Bekdemir, Handan; Candan, Zehra; Saglam, Beylan; Koc, Gonul; Culha, Cavit; Aral, Yalcin

    2016-01-01

    Context: Impact of gestational diabetes mellitus (GDM) on the coagulation system, dynamics involved at a pathophysiological level and the exact mechanism remain unclear. Aims: To evaluate the association between diabetes-related parameters and hemostatic factors to search for a tendency of thrombosis in GDM. Settings and Design: Nineteen pregnant women who had GDM, 16 healthy pregnant and 13 healthy nonpregnant controls admitted to the Endocrinology outpatient clinics were enrolled in the study. Subjects and Methods: Fasting and postprandial glucose, hemoglobin A1c and insulin levels, and insulin resistance; fructosamine, thrombin activatable fibrinolysis inhibitor (TAFI), tissue factor pathway inhibitor (TFPI), plasminogen activator inhibitor Type-1 (PAI-1), tissue-type plasminogen activator (t-PA), fibrinogen, plasminogen and hemoglobin levels, platelet counts, prothrombin time (PT), and activated partial thromboplastin time (aPTT) were studied. Statistical Analysis Used: One-way analysis of variance, Kruskal–Wallis, and post hoc Tukey honestly significant difference or Conover's nonparametric multiple comparison tests for comparison of the study groups. Results: PT and aPTT were significantly lower in GDM patients compared to controls (P < 0.05), whereas fibrinogen and plasminogen levels were significantly higher in this group compared to both nonpregnant and healthy pregnant controls (P < 0.05 for each). TAFI, TFPI, PAI-1, and tissue t-PA levels were not significantly different among groups. Conclusions: Our findings indicate tendency to develop thrombosis in GDM similar to diabetes mellitus; but more comprehensive studies with larger sample size are needed to determine the relationship between GDM and hemostasis. PMID:27365919

  3. Intestinal-specific activatable Myb initiates colon tumorigenesis in mice.

    PubMed

    Malaterre, J; Pereira, L; Putoczki, T; Millen, R; Paquet-Fifield, S; Germann, M; Liu, J; Cheasley, D; Sampurno, S; Stacker, S A; Achen, M G; Ward, R L; Waring, P; Mantamadiotis, T; Ernst, M; Ramsay, R G

    2016-05-12

    Transcription factor Myb is overexpressed in most colorectal cancers (CRC). Patients with CRC expressing the highest Myb are more likely to relapse. We previously showed that mono-allelic loss of Myb in an Adenomatous polyposis coli (APC)-driven CRC mouse model (Apc(Min/+)) significantly improves survival. Here we directly investigated the association of Myb with poor prognosis and how Myb co-operates with tumor suppressor genes (TSGs) (Apc) and cell cycle regulator, p27. Here we generated the first intestinal-specific, inducible transgenic model; a MybER transgene encoding a tamoxifen-inducible fusion protein between Myb and the estrogen receptor-α ligand-binding domain driven by the intestinal-specific promoter, Gpa33. This was to mimic human CRC with constitutive Myb activity in a highly tractable mouse model. We confirmed that the transgene was faithfully expressed and inducible in intestinal stem cells (ISCs) before embarking on carcinogenesis studies. Activation of the MybER did not change colon homeostasis unless one p27 allele was lost. We then established that MybER activation during CRC initiation using a pro-carcinogen treatment, azoxymethane (AOM), augmented most measured aspects of ISC gene expression and function and accelerated tumorigenesis in mice. CRC-associated symptoms of patients including intestinal bleeding and anaemia were faithfully mimicked in AOM-treated MybER transgenic mice and implicated hypoxia and vessel leakage identifying an additional pathogenic role for Myb. Collectively, the results suggest that Myb expands the ISC pool within which CRC is initiated while co-operating with TSG loss. Myb further exacerbates CRC pathology partly explaining why high MYB is a predictor of worse patient outcome. PMID:26300002

  4. Intestinal-specific activatable Myb initiates colon tumorigenesis in mice

    PubMed Central

    Malaterre, J; Pereira, L; Putoczki, T; Millen, R; Paquet-Fifield, S; Germann, M; Liu, J; Cheasley, D; Sampurno, S; Stacker, S A; Achen, M G; Ward, R L; Waring, P; Mantamadiotis, T; Ernst, M; Ramsay, R G

    2016-01-01

    Transcription factor Myb is overexpressed in most colorectal cancers (CRC). Patients with CRC expressing the highest Myb are more likely to relapse. We previously showed that mono-allelic loss of Myb in an Adenomatous polyposis coli (APC)-driven CRC mouse model (ApcMin/+) significantly improves survival. Here we directly investigated the association of Myb with poor prognosis and how Myb co-operates with tumor suppressor genes (TSGs) (Apc) and cell cycle regulator, p27. Here we generated the first intestinal-specific, inducible transgenic model; a MybER transgene encoding a tamoxifen-inducible fusion protein between Myb and the estrogen receptor-α ligand-binding domain driven by the intestinal-specific promoter, Gpa33. This was to mimic human CRC with constitutive Myb activity in a highly tractable mouse model. We confirmed that the transgene was faithfully expressed and inducible in intestinal stem cells (ISCs) before embarking on carcinogenesis studies. Activation of the MybER did not change colon homeostasis unless one p27 allele was lost. We then established that MybER activation during CRC initiation using a pro-carcinogen treatment, azoxymethane (AOM), augmented most measured aspects of ISC gene expression and function and accelerated tumorigenesis in mice. CRC-associated symptoms of patients including intestinal bleeding and anaemia were faithfully mimicked in AOM-treated MybER transgenic mice and implicated hypoxia and vessel leakage identifying an additional pathogenic role for Myb. Collectively, the results suggest that Myb expands the ISC pool within which CRC is initiated while co-operating with TSG loss. Myb further exacerbates CRC pathology partly explaining why high MYB is a predictor of worse patient outcome. PMID:26300002

  5. Beta-lactamase targeted enzyme activatable photosensitizers for antimicrobial PDT

    NASA Astrophysics Data System (ADS)

    Zheng, Xiang; Verma, Sarika; Sallum, Ulysses W.; Hasan, Tayyaba

    2009-06-01

    Photodynamic therapy (PDT) as a treatment modality for infectious disease has shown promise. However, most of the antimicrobial photosensitizers (PS) non-preferentially accumulate in both bacteria and host tissues, causing host tissue phototoxicity during treatment. We have developed a new antimicrobial PDT strategy which exploits beta-lactam resistance mechanism, one of the major drug-resistance bacteria evolved, to achieve enhanced target specificity with limited host damage. Our strategy comprises a prodrug construct with a PS and a quencher linked by beta-lactam ring, resulting in a diminished phototoxicity. This construct, beta-lactamase enzyme-activated-photosensitizer (beta-LEAP), can only be activated in the presence of both light and bacteria, and remains inactive elsewhere such as mammalian tissue. Beta-LEAP construct had shown specific cleavage by purified beta-lactamase and by beta-lactamase over-expressing methicillin resistant Staphylococcus aureus (MRSA). Specific photodynamic toxicity was observed towards MRSA, while dark and light toxicity were equivalent to reference strains. The prodrug design, synthesis and photophysical properties will be discussed.

  6. Tumor microenvironment-specific nanoparticles activatable by stepwise transformation.

    PubMed

    Ko, Hyewon; Son, Soyoung; Jeon, Jueun; Thambi, Thavasyappan; Kwon, Seunglee; Chae, Yee Soo; Kang, Young Mo; Park, Jae Hyung

    2016-07-28

    In an attempt to develop the tumor-targeted nanocarrier which can surmount major challenges for in vivo application, we prepared tumor microenvironment-specific nanoparticles which can be sequentially activated at the extracellular and intracellular levels of tumor tissue by stepwise transformation. This polymeric nanoparticle has been prepared using an amphiphilic polyethyleneimine derivative with the pH-responsive charge-convertible moiety and the reduction-responsive crosslink. Once reaching the tumor tissue in vivo after systemic administration, the surface charge of this nanoparticle can be converted from negative to positive by recognizing the mildly acidic extracellular matrix of tumor, allowing for the enhanced cellular uptake. After the cellular uptake, the nanoparticle can selectively release the drug at the intracellular level since it has the chemically crosslinked core by the disulfide bond which is cleaved in intracellular reductive environment. The tumor microenvironment-specific nanoparticle shows the high tumor targetability and dramatically improves the antitumor efficacy of the drug. PMID:27164544

  7. A tyrosinase inhibitor from Aspergillus niger.

    PubMed

    Vasantha, K Y; Murugesh, C S; Sattur, A P

    2014-10-01

    Tyrosinase, in the presence of oxygen, is the main culprit in post harvest browning of food products, resulting in the drop in its commercial value. In an effort to seek natural tyrosinase inhibitors for food applications, a screening programme was undertaken. Of the 26 fungal cultures isolated from soil samples of Agumbe forest, India, one isolate S16, identified as Aspergillus niger, gave an inhibition of 84 % against the enzyme. The inhibitor was isolated by following an enzyme inhibition assay guided purification protocol. The structure of the inhibitor was elucidated and found to be kojic acid. The IC50 of the Competitive inhibitor was found to be 8.8 μg with a Ki of 0.085 mM. PMID:25328242

  8. Structural Characterization of LRRK2 Inhibitors.

    PubMed

    Gilsbach, Bernd K; Messias, Ana C; Ito, Genta; Sattler, Michael; Alessi, Dario R; Wittinghofer, Alfred; Kortholt, Arjan

    2015-05-14

    Kinase inhibition is considered to be an important therapeutic target for LRRK2 mediated Parkinson's disease (PD). Many LRRK2 kinase inhibitors have been reported but have yet to be optimized in order to qualify as drug candidates for the treatment of the disease. In order to start a structure-function analysis of such inhibitors, we mutated the active site of Dictyostelium Roco4 kinase to resemble LRRK2. Here, we show saturation transfer difference (STD) NMR and the first cocrystal structures of two potent in vitro inhibitors, LRRK2-IN-1 and compound 19, with mutated Roco4. Our data demonstrate that this system can serve as an excellent tool for the structural characterization and optimization of LRRK2 inhibitors using X-ray crystallography and NMR spectroscopy. PMID:25897865

  9. Transdermal delivery of Angiotensin Converting Enzyme inhibitors.

    PubMed

    Helal, Fouad; Lane, Majella E

    2014-09-01

    The Angiotensin Converting Enzyme (ACE) inhibitor class of drugs has been in clinical use since the 1970s for the management of all grades of heart failure, hypertension, diabetic nephropathy and prophylaxis of cardiovascular events. Because of the advantages associated with transdermal delivery compared with oral delivery many researchers have investigated the skin as a portal for administration of ACE inhibitors. This review summarises the various studies reported in the literature describing the development and evaluation of transdermal formulations of ACE inhibitors. Captopril, enalapril maleate, lisinopril dihydrate, perindopril erbumine and trandolapril are the most studied in connection with transdermal preparations. The methodologies reported are considered critically and the limitations of the various skin models used are also highlighted. Finally, opportunities for novel transdermal preparations of ACE inhibitor drugs are discussed with an emphasis on rational formulation design. PMID:24657822

  10. Inhibitors of alanine racemase enzyme: a review.

    PubMed

    Azam, Mohammed Afzal; Jayaram, Unni

    2016-08-01

    Alanine racemase is a fold type III PLP-dependent amino acid racemase enzyme catalysing the conversion of l-alanine to d-alanine utilised by bacterial cell wall for peptidoglycan synthesis. As there are no known homologs in humans, it is considered as an excellent antibacterial drug target. The standard inhibitors of this enzyme include O-carbamyl-d-serine, d-cycloserine, chlorovinyl glycine, alaphosphin, etc. d-Cycloserine is indicated for pulmonary and extra pulmonary tuberculosis but therapeutic use of drug is limited due to its severe toxic effects. Toxic effects due to off-target affinities of cycloserine and other substrate analogs have prompted new research efforts to identify alanine racemase inhibitors that are not substrate analogs. In this review, an updated status of known inhibitors of alanine racemase enzyme has been provided which will serve as a rich source of structural information and will be helpful in generating selective and potent inhibitor of alanine racemase. PMID:26024289

  11. Effects of multiphase flow on corrosion inhibitor

    SciTech Connect

    Chen, Y.; Jepson, W.P.; Chen, H.J.

    1999-11-01

    This paper investigates the inhibition performance of a typical imidazoline based inhibitor under multiphase flow. Electrochemical impedance spectroscopy (EIS) measurements were carried out in a 101.6 mm I.D., 15 m long acrylic flow loop using ASTM substitute saltwater and carbon dioxide gas. This flow loop system can generate slug flow, fill pipe flow and other multiphase flow patterns. Effects of different flow conditions on inhibition performance of this typical inhibitor were examined. The system was maintained at a pressure of 0.136 MPa and a temperature of 40 C. EIS measurements for this inhibitor in a Rotating Cylinder Electrode (RCE) system were also conducted. Different equivalent circuit models were used to fit the experiment data for both the RCE and flow loop systems. The high shear stress and turbulence due to the mixing vortex and the bubble impact in multiphase flow can enhance the corrosion or reduce the inhibition performance of inhibitors.

  12. Musical hallucinations treated with acetylcholinesterase inhibitors.

    PubMed

    Blom, Jan Dirk; Coebergh, Jan Adriaan F; Lauw, René; Sommer, Iris E C

    2015-01-01

    Musical hallucinations are relatively rare auditory percepts which, due to their intrusive nature and the accompanying fear of impending mental decline, tend to cause significant distress and impairment. Although their etiology and pathophysiology appear to be heterogeneous and no evidence-based treatment methods are available, case reports indicate that acetylcholinesterase inhibitors may yield positive results in patients with comorbid hearing loss. We present two female patients (aged 76 and 78 years) both of whom suffered from hearing impairment and practically incessant musical hallucinations. Both patients were successfully treated with the acetylcholinesterase inhibitor rivastigmine. Based on these two case descriptions and an overview of studies describing the use of acetylcholinesterase inhibitors in similar patients, we discuss possible mechanisms and propose further research on the use of acetylcholinesterase inhibitors for musical hallucinations experienced in concordance with hearing loss. PMID:25904872

  13. Musical Hallucinations Treated with Acetylcholinesterase Inhibitors

    PubMed Central

    Blom, Jan Dirk; Coebergh, Jan Adriaan F.; Lauw, René; Sommer, Iris E. C.

    2015-01-01

    Musical hallucinations are relatively rare auditory percepts which, due to their intrusive nature and the accompanying fear of impending mental decline, tend to cause significant distress and impairment. Although their etiology and pathophysiology appear to be heterogeneous and no evidence-based treatment methods are available, case reports indicate that acetylcholinesterase inhibitors may yield positive results in patients with comorbid hearing loss. We present two female patients (aged 76 and 78 years) both of whom suffered from hearing impairment and practically incessant musical hallucinations. Both patients were successfully treated with the acetylcholinesterase inhibitor rivastigmine. Based on these two case descriptions and an overview of studies describing the use of acetylcholinesterase inhibitors in similar patients, we discuss possible mechanisms and propose further research on the use of acetylcholinesterase inhibitors for musical hallucinations experienced in concordance with hearing loss. PMID:25904872

  14. Lipoxygenase inhibitors derived from marine macroalgae.

    PubMed

    Kurihara, Hideyuki; Kagawa, Yoshio; Konno, Remi; Kim, Sang Moo; Takahashi, Koretaro

    2014-03-01

    The solvent extracts from the algae Sargassum thunbergii (Sargassaceae) and Odonthalia corymbifera (Rhodomelaceae) were subjected to soybean lipoxygenase inhibitory screening. Two hydrophobic inhibitors were obtained from the extracts of S. thunbergii through inhibitory assay-guided fractionation. The inhibitors were identified as known exo-methylenic alkapolyenes (6Z,9Z,12Z,15Z)-1,6,9,12,15-henicosapentaene (1) and (6Z,9Z,12Z,15Z,18Z)-1,6,9,12,15,18-henicosahexaene (2). The alkapolyenes 1 and 2 showed higher inhibitory activity than the known inhibitor nordihydroguaiaretic acid (NDGA). Pheophytin a (3) was obtained from the extract of O. corymbifera. The inhibitor 3 also showed higher inhibitory activity than NDGA. This is the first report on lipoxygenase inhibition of exo-methylenic alkapolyenes and a chlorophyll a-related substance. PMID:24495846

  15. Inhibitors of acetylcholinesterase and butyrylcholinesterase meet immunity.

    PubMed

    Pohanka, Miroslav

    2014-01-01

    Acetylcholinesterase (AChE) inhibitors are widely used for the symptomatic treatment of Alzheimer's disease and other dementias. More recent use is for myasthenia gravis. Many of these inhibitors interact with the second known cholinesterase, butyrylcholinesterase (BChE). Further, evidence shows that acetylcholine plays a role in suppression of cytokine release through a "cholinergic anti-inflammatory pathway" which raises questions about the role of these inhibitors in the immune system. This review covers research and discussion of the role of the inhibitors in modulating the immune response using as examples the commonly available drugs, donepezil, galantamine, huperzine, neostigmine and pyridostigmine. Major attention is given to the cholinergic anti-inflammatory pathway, a well-described link between the central nervous system and terminal effector cells in the immune system. PMID:24893223

  16. Drug design from the cryptic inhibitor envelope

    PubMed Central

    Lee, Chul-Jin; Liang, Xiaofei; Wu, Qinglin; Najeeb, Javaria; Zhao, Jinshi; Gopalaswamy, Ramesh; Titecat, Marie; Sebbane, Florent; Lemaitre, Nadine; Toone, Eric J.; Zhou, Pei

    2016-01-01

    Conformational dynamics plays an important role in enzyme catalysis, allosteric regulation of protein functions and assembly of macromolecular complexes. Despite these well-established roles, such information has yet to be exploited for drug design. Here we show by nuclear magnetic resonance spectroscopy that inhibitors of LpxC—an essential enzyme of the lipid A biosynthetic pathway in Gram-negative bacteria and a validated novel antibiotic target—access alternative, minor population states in solution in addition to the ligand conformation observed in crystal structures. These conformations collectively delineate an inhibitor envelope that is invisible to crystallography, but is dynamically accessible by small molecules in solution. Drug design exploiting such a hidden inhibitor envelope has led to the development of potent antibiotics with inhibition constants in the single-digit picomolar range. The principle of the cryptic inhibitor envelope approach may be broadly applicable to other lead optimization campaigns to yield improved therapeutics. PMID:26912110

  17. Pharmacological caspase inhibitors: research towards therapeutic perspectives.

    PubMed

    Kudelova, J; Fleischmannova, J; Adamova, E; Matalova, E

    2015-08-01

    Caspases are key molecules of apoptosis and the inflammatory response. Up-regulation of the caspase cascade contributes to human pathologies such as neurodegenerative and immune disorders. Thus, blocking the excessive apoptosis by pharmacological inhibitors seems promising for therapeutic interventions in such diseases. Caspase inhibitors, both natural and artificial, have been used as research tools and have helped to define the role of the individual caspases in apoptosis and in non-apoptotic processes. Moreover, some caspase inhibitors have demonstrated their therapeutic efficiency in the reduction of cell death and inflammation in animal models of human diseases. However, no drug based on caspase inhibition has been approved on the market until now. Thus, the development of therapeutic approaches that specifically target caspases remains a great challenge and is now the focus of intense biological and clinical interest. Here, we provide a brief review of recent knowledge about pharmacological caspase inhibitors with special focus on their proposed clinical applications. PMID:26348072

  18. Biomass conversion inhibitors and in situ detoxification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inhibitory compounds derived from lignocellulosic biomass pretreatment are classified into aldehydes, ketones, organic acids, and phenols based on their chemical functional group that are toxic to fermentative microorganisms. Inhibitors and effects of inhibition to fermentative microbes vary depend...

  19. Small-Molecule Inhibitors of Urea Transporters

    PubMed Central

    Verkman, Alan S.; Esteva-Font, Cristina; Cil, Onur; Anderson, Marc O.; Li, Fei; Li, Min; Lei, Tianluo; Ren, Huiwen; Yang, Baoxue

    2015-01-01

    Urea transporter (UT) proteins, which include isoforms of UT-A in kidney tubule epithelia and UT-B in vasa recta endothelia and erythrocytes, facilitate urinary concentrating function. Inhibitors of urea transporter function have potential clinical applications as sodium-sparing diuretics, or ‘urearetics,’ in edema from different etiologies, such as congestive heart failure and cirrhosis, as well as in syndrome of inappropriate antidiuretic hormone (SIADH). High-throughput screening of drug-like small molecules has identified UT-A and UT-B inhibitors with nanomolar potency. Inhibitors have been identified with different UT-A versus UT-B selectivity profiles and putative binding sites on UT proteins. Studies in rodent models support the utility of UT inhibitors in reducing urinary concentration, though testing in clinically relevant animal models of edema has not yet been done. PMID:25298345

  20. Progress and prospects on DENV protease inhibitors.

    PubMed

    Timiri, Ajay Kumar; Sinha, Barij Nayan; Jayaprakash, Venkatesan

    2016-07-19

    New treatments are desperately required to combat increasing rate of dengue fever cases reported in tropical and sub-tropical parts of the world. Among the ten proteins (structural and non-structural) encoded by dengue viral genome, NS2B-NS3 protease is an ideal target for drug discovery. It is responsible for the processing of poly protein that is required for genome replication of the virus. Moreover, inhibitors designed against proteases were found successful in Human Immuno-deficiency Virus (HIV) and Hepatitis C Virus (HCV). Complete molecular mechanism and a survey of inhibitors reported against dengue protease will be helpful in designing effective and potent inhibitors. This review provides an insight on molecular mechanism of dengue virus protease and covers up-to-date information on different inhibitors reported against dengue proteases with medicinal chemistry perspective. PMID:27092412

  1. Inhibitors of Acetylcholinesterase and Butyrylcholinesterase Meet Immunity

    PubMed Central

    Pohanka, Miroslav

    2014-01-01

    Acetylcholinesterase (AChE) inhibitors are widely used for the symptomatic treatment of Alzheimer’s disease and other dementias. More recent use is for myasthenia gravis. Many of these inhibitors interact with the second known cholinesterase, butyrylcholinesterase (BChE). Further, evidence shows that acetylcholine plays a role in suppression of cytokine release through a “cholinergic anti-inflammatory pathway” which raises questions about the role of these inhibitors in the immune system. This review covers research and discussion of the role of the inhibitors in modulating the immune response using as examples the commonly available drugs, donepezil, galantamine, huperzine, neostigmine and pyridostigmine. Major attention is given to the cholinergic anti-inflammatory pathway, a well-described link between the central nervous system and terminal effector cells in the immune system. PMID:24893223

  2. Temperature effects on inhibitors and corrosion inhibition

    SciTech Connect

    Raman, A.

    1996-12-01

    Inhibitor systems commonly employed in industrial operations at elevated and high temperatures are surveyed and the available literature data on their performance characteristics at elevated temperatures are analyzed. The functional behavior of phosphates, amines, benzotriazole, and other important inhibitors are briefly summarized. The inhibitors degrade due to thermal decomposition and/or reaction on the metal surface or with other species present in the environment. Degradation modes of various kinds of amines used in steam systems are reviewed and the resultant limitations for use pointed out. Inhibitor systems in heating, heat exchanger-type cooling, hot acid pickling, in hot corrosive environments in turbine engines, as well as systems to prevent stress corrosion cracking at elevated temperatures are analyzed based on literature data.

  3. Selective Phosphodiesterase 4B Inhibitors: A Review

    PubMed Central

    Azam, Mohammed Afzal; Tripuraneni, Naga Srinivas

    2014-01-01

    Abstract Phosphodiesterase 4B (PDE4B) is a member of the phosphodiesterase family of proteins that plays a critical role in regulating intracellular levels of cyclic adenosine monophosphate (cAMP) by controlling its rate of degradation. It has been demonstrated that this isoform is involved in the orchestra of events which includes inflammation, schizophrenia, cancers, chronic obstructive pulmonary disease, contractility of the myocardium, and psoriatic arthritis. Phosphodiesterase 4B has constituted an interesting target for drug development. In recent years, a number of PDE4B inhibitors have been developed for their use as therapeutic agents. In this review, an up-to-date status of the inhibitors investigated for the inhibition of PDE4B has been given so that this rich source of structural information of presently known PDE4B inhibitors could be helpful in generating a selective and potent inhibitor of PDE4B. PMID:25853062

  4. Ocular Toxicity of Tyrosine Kinase Inhibitors

    PubMed Central

    Davis, Mary Elizabeth

    2016-01-01

    Purpose/Objectives To review common tyrosine kinase inhibitors, as well as their ocular side effects and management. Data Sources A comprehensive literature search was conducted using cINahl®, Pubmed, and cochrane databases for articles published since 2004 with the following search terms: ocular toxicities, tyrosine kinase inhibitors, ophthalmology, adverse events, eye, and vision. Data Synthesis Tyrosine kinase inhibitors can cause significant eye toxicity. Conclusions Given the prevalence of new tyrosine kinase inhibitor therapies and the complexity of possible pathogenesis of ocular pathology, oncology nurses can appreciate the occurrence of ocular toxicities and the role of nursing in the management of these problems. Implications for Nursing Knowledge of the risk factors and etiology of ocular toxicity of targeted cancer therapies can guide nursing assessment, enhance patient education, and improve care management. Including a review of eye symptoms and vision issues in nursing assessment can enhance early detection and treatment of ocular toxicity. PMID:26906134

  5. Proteasome inhibitor associated thrombotic microangiopathy.

    PubMed

    Yui, Jennifer C; Van Keer, Jan; Weiss, Brendan M; Waxman, Adam J; Palmer, Matthew B; D'Agati, Vivette D; Kastritis, Efstathios; Dimopoulos, Meletios A; Vij, Ravi; Bansal, Dhruv; Dingli, David; Nasr, Samih H; Leung, Nelson

    2016-09-01

    A variety of medications have been implicated in the causation of thrombotic microangiopathy (TMA). Recently, a few case reports have emerged of TMA attributed to the proteasome inhibitors (PI) bortezomib and carfilzomib in patients with multiple myeloma. The aim of this case series was to better characterize the role of PI in the etiology of drug-induced TMA. We describe eleven patients from six medical centers from around the world who developed TMA while being treated with PI. The median time between medication initiation and diagnosis of TMA was 21 days (range 5 days to 17 months). Median laboratory values at diagnosis included hemoglobin-7.5 g dL(-1) , platelet count-20 × 10(9) /L, LDH-698 U L(-1) , creatinine-3.12 mg dL(-1) . No patient had any other cause of TMA, including ADAMTS13 inhibition, other malignancy or use of any other medication previously associated with TMA. Nine patients had resolution of TMA without evidence of hemolysis after withdrawal of PI. Two patients had stabilization of laboratory values but persistent evidence of hemolysis despite medication withdrawal. One patient had recurrence of TMA with rechallenge of PI. There is a strong level of evidence that PI can cause DITMA. In evaluating patients with suspected TMA, PI use should be recognized as a potential etiology, and these medications should be discontinued promptly if thought to be the cause of TMA. Am. J. Hematol. 91:E348-E352, 2016. © 2016 Wiley Periodicals, Inc. PMID:27286661

  6. Proton pump inhibitors and pain.

    PubMed

    Smith, Howard S; Dhingra, Reena; Ryckewaert, Lori; Bonner, Dave

    2009-01-01

    There may be a relationship between proton pump inhibitors (PPIs) and iron absorption. PPIs may decrease the amount of iron absorbed gastrointestinally specifically due to alteration of the pH in the duodenum. Restless legs syndrome (RLS) is a sensorimotor disorder that includes an urge to move legs, accompanied or caused by uncomfortable and unpleasant sensations in the legs; the urge to move begins or worsens during periods of rest or inactivity, the urge to move is partially or totally relieved by movement, and the urge is worse or only occurs at night. In the majority of the restless leg syndrome population, the sensation is deep seated, often described as being in the shin bones, and most commonly felt between the knee and ankle. It may be described as a creepy, shock-like, tense, electric, buzzing, itchy, or even numb sensation. A subpopulation of this restless leg syndrome patient population experiences restless leg syndrome associated pain (RLSAP) that has been described as a deep "achy pain." This pain has not been found to be relieved by many of the typical over the counter analgesics. Often, constant movement of the legs appears to be the only remedy, as these sensations usually appear during periods of rest. Furthermore, there appears to be an association between iron deficiency and those suffering from Restless Leg Syndrome (RLS). The authors theorize that there may be a possible correlation between PPIs and the symptoms (e.g. pain) associated with RLS. The authors propose that PPIs, such as omeprazole, may interfere with iron absorption in certain patients and that a subpopulation of patients who develop significant iron deficiency characterized by low serum ferritin levels while on PPIs may also develop RLS-like symptoms (including RLSAP). While there is no robust direct evidence to support any associations of PPIs and iron deficiency or PPIs associated with RLS-like symptoms (including RLSAP), it is hoped that this manuscript may spark research

  7. 2,4-Diaminopyrimidine MK2 inhibitors. Part I: Observation of an unexpected inhibitor binding mode

    SciTech Connect

    Argiriadi, Maria A.; Ericsson, Anna M.; Harris, Christopher M.; Banach, David L.; Borhani, David W.; Calderwood, David J.; Demers, Megan D.; DiMauro, Jennifer; Dixon, Richard W.; Hardman, Jennifer; Kwak, Silvia; Li, Biqin; Mankovich, John A.; Marcotte, Douglas; Mullen, Kelly D.; Ni, Baofu; Pietras, M.; Sadhukhan, Ramkrishna; Sousa, Silvino; Tomlinson, Medha J.; Wang, L.; Xiang, T.; Talanian, R.V.

    2010-09-17

    MK2 is a Ser/Thr kinase of significant interest as an anti-inflammatory drug discovery target. Here we describe the development of in vitro tools for the identification and characterization of MK2 inhibitors, including validation of inhibitor interactions with the crystallography construct and determination of the unique binding mode of 2,4-diaminopyrimidine inhibitors in the MK2 active site.

  8. HIV pharmacotherapy: A review of integrase inhibitors.

    PubMed

    Wong, Elaine; Trustman, Nathan; Yalong, April

    2016-02-01

    Integrase strand transfer inhibitors (INSTIs) are a class of antiretroviral agents used to treat HIV. These drugs--raltegravir, elvitegravir, and dolutegravir--are preferred options for treatment-naïve patients when used in combination with two nucleoside reverse transcriptase inhibitors. Based on clinical trials, INSTIs have been proven to be effective with minimal safety concerns. This article reviews the pharmacologic profile, role in therapy, and safety and efficacy of each agent. PMID:26818644

  9. Influenza virus neuraminidase: structure, antibodies, and inhibitors.

    PubMed Central

    Colman, P. M.

    1994-01-01

    The determination of the 3-dimensional structure of the influenza virus neuraminidase in 1983 has served as a platform for understanding interactions between antibodies and protein antigens, for investigating antigenic variation in influenza viruses, and for devising new inhibitors of the enzyme. That work is reviewed here, together with more recent developments that have resulted in one of the inhibitors entering clinical trials as an anti-influenza virus drug. PMID:7849585

  10. Heterocyclics as corrosion inhibitors for acid media

    SciTech Connect

    Ajmal, M.; Khan, M.A.W.; Ahmad, S.; Quraishi, M.A.

    1996-12-01

    The available literature on the use of heterocyclic compounds as corrosion inhibitors in acid media has been reviewed. It has been noted that the workers in this field have either used sulfur or nitrogen containing heterocyclic compounds for studying inhibition action. The authors have synthesized compounds containing sulfur and nitrogen both in the same ring and studied their inhibition action in acid media. These compounds were found to be better inhibitors than those containing either atoms alone.

  11. On the selectivity of neuronal NOS inhibitors

    PubMed Central

    Pigott, B; Bartus, K; Garthwaite, J

    2013-01-01

    Background and Purpose Isoform-selective inhibitors of NOS enzymes are desirable as research tools and for potential therapeutic purposes. Vinyl-l-N-5-(1-imino-3-butenyl)-l-ornithine (l-VNIO) and Nω-propyl-l-arginine (NPA) purportedly have good selectivity for neuronal over endothelial NOS under cell-free conditions, as does N-[(3-aminomethyl)benzyl]acetamidine (1400W), which is primarily an inducible NOS inhibitor. Although used in numerous investigations in vitro and in vivo, there have been surprisingly few tests of the potency and selectivity of these compounds in cells. This study addresses this deficiency and evaluates the activity of new and potentially better pyrrolidine-based compounds. Experimental Approach The inhibitors were evaluated by measuring their effect on NMDA-evoked cGMP accumulation in rodent hippocampal slices, a response dependent on neuronal NOS, and ACh-evoked cGMP synthesis in aortic rings of the same animals, an endothelial NOS-dependent phenomenon. Key Results l-VNIO, NPA and 1400W inhibited responses in both tissues but all showed less than fivefold higher potency in the hippocampus than in the aorta, implying useless selectivity for neuronal over endothelial NOS at the tissue level. In addition, the inhibitors had a 25-fold lower potency in the hippocampus than reported previously, the IC50 values being approximately 1 μM for l-VNIO and NPA, and 150 μM for 1400W. Pyrrolidine-based inhibitors were similarly weak and nonselective. Conclusion and Implications The results suggest that l-VNIO, NPA and 1400W, as well as the newer pyrrolidine-type inhibitors, cannot be used as neuronal NOS inhibitors in cells without stringent verification. The identification of inhibitors with useable selectivity in cells and tissues remains an important goal. PMID:23072468

  12. Endogenous angiogenesis inhibitors and their therapeutic implications.

    PubMed

    Cao, Y

    2001-04-01

    A number of endogenous inhibitors targeting the tumor vasculature have recently been identified using in vitro and in vivo antiangiogenesis models. While many of these angiogenesis inhibitors display a broad spectrum of biological actions on several systems in the body, several inhibitors including angiostatin, endostatin, and serpin antithrombin seem to act specifically on the proliferating endothelial cell compartment of the newly formed blood vessels. The discovery of these specific endothelial inhibitors not only increases our understanding of the functions of these molecules in the regulation of physiological and pathological angiogenesis, but may also provide an important therapeutic strategy for the treatment of cancer and other angiogenesis dependent diseases, including diabetic retinopathy and chronic inflammations. Systemic administration of these angiogenesis inhibitors in animals significantly suppresses the growth of a variety of tumors and their metastases. However, their production as functional recombinant proteins has been proven to be difficult. In addition, high dosages of these inhibitors are required to suppress tumor growth in animal studies. Other disadvantages of the antiangiogenic protein therapy include repeated injections, prolonged treatment, transmission of toxins and infectious particles, and high cost for manufacturing large amounts of protein molecules. Thus, alternative strategies need to be developed in order to improve the clinical settings of antiangiogenic therapy. Developments of these strategies are ongoing and they include identification of more potent inhibitors, antiangiogenic gene therapy, improvement of protein/compound half-lives in the circulation, increase of their concentrations at the disease location, and combinatorial therapies with approaches including chemotherapy, radiotherapy, and immunotherapy. Despite the above-mentioned disadvantages, a few inhibitors have entered into the early stages of clinical trials and

  13. Update on TNF Inhibitors in Dermatology.

    PubMed

    Sobell, Jeffrey M

    2016-06-01

    Emerging data describe new potential indications for tumor necrosis factor (TNF) inhibitors in dermatology, including pediatric psoriasis and hidradenitis suppurativa. New biosimilar TNF agents are in late stages of development and may be available in the United States in the near future. Biosimilar agents are similar but not identical to available TNF inhibitors, and approval requires extensive analytic, toxicity, pharmacokinetic, pharmacodynamic, and clinical testing. Semin Cutan Med Surg 35(supp6):S104-S106. PMID:27537073

  14. Aromatase inhibitors in the treatment of endometriosis.

    PubMed

    Słopień, Radosław; Męczekalski, Błażej

    2016-03-01

    Endometriosis is a chronic inflammatory condition in which foci of endometrial tissue grow outside of the uterine cavity. Endometriosis was estimated to affect 176 million women of childbearing potential all over the world in 2010. The presence of extrauterine endometrial tissue is associated with pain and infertility. Typical symptoms of endometriosis include dysmenorrhoea, dyspareunia, heavy menstrual periods (menorrhagia), pelvic pain that is not related to menstrual cycles, dysuria, and chronic fatigue. Medical treatments for endometriosis include combined oral contraceptive pills, danazol, gestrinone, medroxyprogesterone acetate, and gonadotropin-releasing hormone agonists (aGnRHs). A new class of medications called aromatase inhibitors has been identified in recent years as potential therapeutic agents for endometriosis. This article provides general information about aromatase inhibitors, their use in gynaecology, and their adverse effects. In particular, the paper discusses the use of aromatase inhibitors in the treatment of endometriosis in postmenopausal women. Unlike oral contraceptives, gestagens, aGnRHs, and danazol, which suppress ovarian oestrogen synthesis, aromatase inhibitors inhibit mainly extra-ovarian synthesis of oestrogens. Therefore, the use of aromatase inhibitors seems to be particularly relevant in older patients, as most of the body's oestrogen is produced outside the ovaries after menopause. The paper discusses also the use of aromatase inhibitors in the treatment of pain associated with endometriosis and infertility caused by endometriosis. PMID:27095958

  15. FERRITIN H INDUCTION BY HISTONE DEACETYLASE INHIBITORS

    PubMed Central

    Wang, Wei; Di, Xiumin; Torti, Suzy V.; Torti, Frank M.

    2010-01-01

    Because both iron deficiency and iron excess are deleterious to normal cell function, the intracellular level of iron must be tightly controlled. Ferritin, an iron binding protein, regulates iron balance by storing iron in a bioavailable but non-toxic form. Ferritin protein comprises two subunits: ferritin H, which contains ferroxidase activity, and ferritin L. Here we demonstrate that ferritin H mRNA and protein are induced by histone deacetylase inhibitors (HDAC inhibitors), a promising class of anti-cancer drugs, in cultured human cancer cells. Deletion analysis and EMSA assays reveal that the induction of ferritin H occurs at a transcriptional level via Sp1 and NF-Y binding sites near the transcriptional start site of the human ferritin H promoter. Classically, HDAC inhibitors modulate gene expression by increasing histone acetylation. However, ChIP assays demonstrate that HDAC inhibitors induce ferritin H transcription by increasing NF-Y binding to the ferritin H promoter without changes in histone acetylation. These results identify ferritin H as a new target of HDAC inhibitors, and recruitment of NF-Y as a novel mechanism of action of HDAC inhibitors. PMID:20385107

  16. Discovery of Novel Haloalkane Dehalogenase Inhibitors

    PubMed Central

    Buryska, Tomas; Daniel, Lukas; Kunka, Antonin; Brezovsky, Jan; Damborsky, Jiri

    2016-01-01

    Haloalkane dehalogenases (HLDs) have recently been discovered in a number of bacteria, including symbionts and pathogens of both plants and humans. However, the biological roles of HLDs in these organisms are unclear. The development of efficient HLD inhibitors serving as molecular probes to explore their function would represent an important step toward a better understanding of these interesting enzymes. Here we report the identification of inhibitors for this enzyme family using two different approaches. The first builds on the structures of the enzymes' known substrates and led to the discovery of less potent nonspecific HLD inhibitors. The second approach involved the virtual screening of 150,000 potential inhibitors against the crystal structure of an HLD from the human pathogen Mycobacterium tuberculosis H37Rv. The best inhibitor exhibited high specificity for the target structure, with an inhibition constant of 3 μM and a molecular architecture that clearly differs from those of all known HLD substrates. The new inhibitors will be used to study the natural functions of HLDs in bacteria, to probe their mechanisms, and to achieve their stabilization. PMID:26773086

  17. PARP1 Inhibitors: antitumor drug design

    PubMed Central

    Malyuchenko, N. V.; Kotova, E. Yu.; Kulaeva, O. I.; Kirpichnikov, M. P.; Studitskiy, V. M.

    2015-01-01

    The poly (ADP-ribose) polymerase 1 (PARP1) enzyme is one of the promising molecular targets for the discovery of antitumor drugs. PARP1 is a common nuclear protein (1–2 million molecules per cell) serving as a “sensor” for DNA strand breaks. Increased PARP1 expression is sometimes observed in melanomas, breast cancer, lung cancer, and other neoplastic diseases. The PARP1 expression level is a prognostic indicator and is associated with a poor survival prognosis. There is evidence that high PARP1 expression and treatment-resistance of tumors are correlated. PARP1 inhibitors are promising antitumor agents, since they act as chemo- and radiosensitizers in the conventional therapy of malignant tumors. Furthermore, PARP1 inhibitors can be used as independent, effective drugs against tumors with broken DNA repair mechanisms. Currently, third-generation PARP1 inhibitors are being developed, many of which are undergoing Phase II clinical trials. In this review, we focus on the properties and features of the PARP1 inhibitors identified in preclinical and clinical trials. We also describe some problems associated with the application of PARP1 inhibitors. The possibility of developing new PARP1 inhibitors aimed at DNA binding and transcriptional activity rather than the catalytic domain of the protein is discussed. PMID:26483957

  18. Discovery of Novel Haloalkane Dehalogenase Inhibitors.

    PubMed

    Buryska, Tomas; Daniel, Lukas; Kunka, Antonin; Brezovsky, Jan; Damborsky, Jiri; Prokop, Zbynek

    2016-03-01

    Haloalkane dehalogenases (HLDs) have recently been discovered in a number of bacteria, including symbionts and pathogens of both plants and humans. However, the biological roles of HLDs in these organisms are unclear. The development of efficient HLD inhibitors serving as molecular probes to explore their function would represent an important step toward a better understanding of these interesting enzymes. Here we report the identification of inhibitors for this enzyme family using two different approaches. The first builds on the structures of the enzymes' known substrates and led to the discovery of less potent nonspecific HLD inhibitors. The second approach involved the virtual screening of 150,000 potential inhibitors against the crystal structure of an HLD from the human pathogen Mycobacterium tuberculosis H37Rv. The best inhibitor exhibited high specificity for the target structure, with an inhibition constant of 3 μM and a molecular architecture that clearly differs from those of all known HLD substrates. The new inhibitors will be used to study the natural functions of HLDs in bacteria, to probe their mechanisms, and to achieve their stabilization. PMID:26773086

  19. Aromatase inhibitors in the treatment of endometriosis

    PubMed Central

    Męczekalski, Błażej

    2016-01-01

    Endometriosis is a chronic inflammatory condition in which foci of endometrial tissue grow outside of the uterine cavity. Endometriosis was estimated to affect 176 million women of childbearing potential all over the world in 2010. The presence of extrauterine endometrial tissue is associated with pain and infertility. Typical symptoms of endometriosis include dysmenorrhoea, dyspareunia, heavy menstrual periods (menorrhagia), pelvic pain that is not related to menstrual cycles, dysuria, and chronic fatigue. Medical treatments for endometriosis include combined oral contraceptive pills, danazol, gestrinone, medroxyprogesterone acetate, and gonadotropin-releasing hormone agonists (aGnRHs). A new class of medications called aromatase inhibitors has been identified in recent years as potential therapeutic agents for endometriosis. This article provides general information about aromatase inhibitors, their use in gynaecology, and their adverse effects. In particular, the paper discusses the use of aromatase inhibitors in the treatment of endometriosis in postmenopausal women. Unlike oral contraceptives, gestagens, aGnRHs, and danazol, which suppress ovarian oestrogen synthesis, aromatase inhibitors inhibit mainly extra-ovarian synthesis of oestrogens. Therefore, the use of aromatase inhibitors seems to be particularly relevant in older patients, as most of the body's oestrogen is produced outside the ovaries after menopause. The paper discusses also the use of aromatase inhibitors in the treatment of pain associated with endometriosis and infertility caused by endometriosis. PMID:27095958

  20. Potent pyrrolidine- and piperidine-based BACE-1 inhibitors

    SciTech Connect

    Iserloh, U.; Wu, Y.; Cumming, J.N.; Pan, J.; Wang, L.Y.; Stamford, A.W.; Kennedy, M.E.; Kuvelkar, R.; Chen, X.; Parker, E.M.; Strickland, C.; Voigt, J.

    2008-08-18

    Based on lead compound 1 identified from the patent literature, we developed novel patentable BACE-1 inhibitors by introducing a cyclic amine scaffold. Extensive SAR studies on both pyrrolidines and piperidines ultimately led to inhibitor 2f, one of the most potent inhibitors synthesized to date. The discovery and development of novel BACE-1 inhibitors incorporating a cyclic amine scaffold is described.

  1. Corrosion inhibitors for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1978-01-01

    Inhibitors which appeared promising in previous tests and additional inhibitors including several proprietary products were evaluated. Evaluation of the inhibitors was based on corrosion protection afforded an aluminum-mild steel-copper-stainless steel assembly in a hot corrosive water. Of the inhibitors tested two were found to be effective and show promise for protecting multimetallic solar heating systems.

  2. Selective serotonin reuptake inhibitor exposure.

    PubMed

    Fitzgerald, Kevin T; Bronstein, Alvin C

    2013-02-01

    Many antidepressants inhibit serotonin or norepinephrine reuptake or both to achieve their clinical effect. The selective serotonin reuptake inhibitor class of antidepressants (SSRIs) includes citalopram, escitalopram (active enantiomer of citalopram), fluoxetine, fluvoxamine, paroxetine, and sertraline. The SSRIs are as effective as tricyclic antidepressants in treatment of major depression with less significant side effects. As a result, they have become the largest class of medications prescribed to humans for depression. They are also used to treat obsessive-compulsive disorder, panic disorders, alcoholism, obesity, migraines, and chronic pain. An SSRI (fluoxetine) has been approved for veterinary use in treatment of canine separation anxiety. SSRIs act specifically on synaptic serotonin concentrations by blocking its reuptake in the presynapse and increasing levels in the presynaptic membrane. Clinical signs of SSRI overdose result from excessive amounts of serotonin in the central nervous system. These signs include nausea, vomiting, mydriasis, hypersalivation, and hyperthermia. Clinical signs are dose dependent and higher dosages may result in the serotonin syndrome that manifests itself as ataxia, tremors, muscle rigidity, hyperthermia, diarrhea, and seizures. Current studies reveal no increase in appearance of any specific clinical signs of serotonin toxicity with regard to any SSRI medication. In people, citalopram has been reported to have an increased risk of electrocardiographic abnormalities. Diagnosis of SSRI poisoning is based on history, clinical signs, and response to therapy. No single clinical test is currently available to confirm SSRI toxicosis. The goals of treatment in this intoxication are to support the animal, prevent further absorption of the drug, support the central nervous system, control hyperthermia, and halt any seizure activity. The relative safety of the SSRIs in overdose despite the occurrence of serotonin syndrome makes them

  3. Combined effects of EGFR tyrosine kinase inhibitors and vATPase inhibitors in NSCLC cells

    SciTech Connect

    Jin, Hyeon-Ok; Hong, Sung-Eun; Kim, Chang Soon; Park, Jin-Ah; Kim, Jin-Hee; Kim, Ji-Young; Kim, Bora; Chang, Yoon Hwan; Hong, Seok-Il; Hong, Young Jun; Park, In-Chul; Lee, Jin Kyung

    2015-08-15

    Despite excellent initial clinical responses of non-small cell lung cancer (NSCLC) patients to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), many patients eventually develop resistance. According to a recent report, vacuolar H + ATPase (vATPase) is overexpressed and is associated with chemotherapy drug resistance in NSCLC. We investigated the combined effects of EGFR TKIs and vATPase inhibitors and their underlying mechanisms in the regulation of NSCLC cell death. We found that combined treatment with EGFR TKIs (erlotinib, gefitinib, or lapatinib) and vATPase inhibitors (bafilomycin A1 or concanamycin A) enhanced synergistic cell death compared to treatments with each drug alone. Treatment with bafilomycin A1 or concanamycin A led to the induction of Bnip3 expression in an Hif-1α dependent manner. Knock-down of Hif-1α or Bnip3 by siRNA further enhanced cell death induced by bafilomycin A1, suggesting that Hif-1α/Bnip3 induction promoted resistance to cell death induced by the vATPase inhibitors. EGFR TKIs suppressed Hif-1α and Bnip3 expression induced by the vATPase inhibitors, suggesting that they enhanced the sensitivity of the cells to these inhibitors by decreasing Hif-1α/Bnip3 expression. Taken together, we conclude that EGFR TKIs enhance the sensitivity of NSCLC cells to vATPase inhibitors by decreasing Hif-1α/Bnip3 expression. We suggest that combined treatment with EGFR TKIs and vATPase inhibitors is potentially effective for the treatment of NSCLC. - Highlights: • Co-treatment with EGFR TKIs and vATPase inhibitors induces synergistic cell death • EGFR TKIs enhance cell sensitivity to vATPase inhibitors via Hif-1α downregulation • Co-treatment of these inhibitors is potentially effective for the treatment of NSCLC.

  4. SGLT2 Inhibitors and the Diabetic Kidney.

    PubMed

    Fioretto, Paola; Zambon, Alberto; Rossato, Marco; Busetto, Luca; Vettor, Roberto

    2016-08-01

    Diabetic nephropathy (DN) is the most common cause of end-stage renal disease worldwide. Blood glucose and blood pressure control reduce the risk of developing this complication; however, once DN is established, it is only possible to slow progression. Sodium-glucose cotransporter 2 (SGLT2) inhibitors, the most recent glucose-lowering oral agents, may have the potential to exert nephroprotection not only through improving glycemic control but also through glucose-independent effects, such as blood pressure-lowering and direct renal effects. It is important to consider, however, that in patients with impaired renal function, given their mode of action, SGLT2 inhibitors are less effective in lowering blood glucose. In patients with high cardiovascular risk, the SGLT2 inhibitor empagliflozin lowered the rate of cardiovascular events, especially cardiovascular death, and substantially reduced important renal outcomes. Such benefits on DN could derive from effects beyond glycemia. Glomerular hyperfiltration is a potential risk factor for DN. In addition to the activation of the renin-angiotensin-aldosterone system, renal tubular factors, including SGLT2, contribute to glomerular hyperfiltration in diabetes. SGLT2 inhibitors reduce sodium reabsorption in the proximal tubule, causing, through tubuloglomerular feedback, afferent arteriole vasoconstriction and reduction in hyperfiltration. Experimental studies showed that SGLT2 inhibitors reduced hyperfiltration and decreased inflammatory and fibrotic responses of proximal tubular cells. SGLT2 inhibitors reduced glomerular hyperfiltration in patients with type 1 diabetes, and in patients with type 2 diabetes, they caused transient acute reductions in glomerular filtration rate, followed by a progressive recovery and stabilization of renal function. Interestingly, recent studies consistently demonstrated a reduction in albuminuria. Although these data are promising, only dedicated renal outcome trials will clarify whether

  5. Three Decades of β-Lactamase Inhibitors

    PubMed Central

    Drawz, Sarah M.; Bonomo, Robert A.

    2010-01-01

    Summary: Since the introduction of penicillin, β-lactam antibiotics have been the antimicrobial agents of choice. Unfortunately, the efficacy of these life-saving antibiotics is significantly threatened by bacterial β-lactamases. β-Lactamases are now responsible for resistance to penicillins, extended-spectrum cephalosporins, monobactams, and carbapenems. In order to overcome β-lactamase-mediated resistance, β-lactamase inhibitors (clavulanate, sulbactam, and tazobactam) were introduced into clinical practice. These inhibitors greatly enhance the efficacy of their partner β-lactams (amoxicillin, ampicillin, piperacillin, and ticarcillin) in the treatment of serious Enterobacteriaceae and penicillin-resistant staphylococcal infections. However, selective pressure from excess antibiotic use accelerated the emergence of resistance to β-lactam-β-lactamase inhibitor combinations. Furthermore, the prevalence of clinically relevant β-lactamases from other classes that are resistant to inhibition is rapidly increasing. There is an urgent need for effective inhibitors that can restore the activity of β-lactams. Here, we review the catalytic mechanisms of each β-lactamase class. We then discuss approaches for circumventing β-lactamase-mediated resistance, including properties and characteristics of mechanism-based inactivators. We next highlight the mechanisms of action and salient clinical and microbiological features of β-lactamase inhibitors. We also emphasize their therapeutic applications. We close by focusing on novel compounds and the chemical features of these agents that may contribute to a “second generation” of inhibitors. The goal for the next 3 decades will be to design inhibitors that will be effective for more than a single class of β-lactamases. PMID:20065329

  6. Polyphenol oxidase inhibitor(s) from German cockroach (Blattella germanica) extract

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An extract from German cockroach appears effective in inhibiting browning on apples and potatoes. Successful identification of inhibitor(s) of PPO from German cockroach would be useful to the fruit and vegetable segments of the food industry, due to the losses they incur from enzymatic browning. Ide...

  7. Inhibitors Selective for Mycobacterial Versus Human Proteasomes

    SciTech Connect

    Lin, G.; Li, D; Sorio de Carvalho, L; Deng, H; Tao, H; Vogt, G; Wu, K; Schneider, J; Chidawanyika, T; et. al.

    2009-01-01

    Many anti-infectives inhibit the synthesis of bacterial proteins, but none selectively inhibits their degradation. Most anti-infectives kill replicating pathogens, but few preferentially kill pathogens that have been forced into a non-replicating state by conditions in the host. To explore these alternative approaches we sought selective inhibitors of the proteasome of Mycobacterium tuberculosis. Given that the proteasome structure is extensively conserved, it is not surprising that inhibitors of all chemical classes tested have blocked both eukaryotic and prokaryotic proteasomes, and no inhibitor has proved substantially more potent on proteasomes of pathogens than of their hosts. Here we show that certain oxathiazol-2-one compounds kill non-replicating M.?tuberculosis and act as selective suicide-substrate inhibitors of the M.?tuberculosis proteasome by cyclocarbonylating its active site threonine. Major conformational changes protect the inhibitor-enzyme intermediate from hydrolysis, allowing formation of an oxazolidin-2-one and preventing regeneration of active protease. Residues outside the active site whose hydrogen bonds stabilize the critical loop before and after it moves are extensively non-conserved. This may account for the ability of oxathiazol-2-one compounds to inhibit the mycobacterial proteasome potently and irreversibly while largely sparing the human homologue.

  8. Inhibitors in LPE growth of garnets

    NASA Astrophysics Data System (ADS)

    De Roode, W. H.; Robertson, J. M.

    1983-09-01

    The growth rate of LPE growth garnets can be reduced considerably by the addition of small amounts of group II oxides. This effect can be helpful for the controlled growth of very thin garnet films for sub-micron bubbles and optical devices. The largest effect was found with the addition of Mg 2+ and Ca 2+, resulting in a maximum decrease of the growth rate of approximately 70%. A semi-empirical formula was used to describe the growth rate as a function of the dipping temperature. The change in the growth rate on the addition of the inhibitor ion at constant temperature was found to be proportional to ( aMO)/( aMO+2 Ln 2O 3), where M is a group II element, Ln 2O 2 is the sum of the yttrium and RE oxides in the melt, and a is the inhibitor factor. The value of the inhibitor factor depends on both the inhibitor ion as well as the composition of the garnet. The lowering of the growth rate on the addition of an inhibitor ion is explained by the introduction of an extra growth resistance due to the charge compensation mechanism of the divalent ions. The influence of the different charge compensation possibilities in the garnet system is examined and the relative importance of these possibilities for charge compensation is discussed.

  9. Clinical Development of Immune Checkpoint Inhibitors.

    PubMed

    Ito, Ayumu; Kondo, Shunsuke; Tada, Kohei; Kitano, Shigehisa

    2015-01-01

    Recent progress in cancer immunotherapy has been remarkable. Most striking are the clinical development and approval of immunomodulators, also known as immune checkpoint inhibitors. These monoclonal antibodies (mAb) are directed to immune checkpoint molecules, which are expressed on immune cells and mediate signals to attenuate excessive immune reactions. Although mAbs targeting tumor associated antigens, such as anti-CD20 mAb and anti-Her2 mAb, directly recognize tumor cells and induce cell death, immune checkpoint inhibitors restore and augment the antitumor immune activities of cytotoxic T cells by blocking immune checkpoint molecules on T cells or their ligands on antigen presenting and tumor cells. Based on preclinical data, many clinical trials have demonstrated the acceptable safety profiles and efficacies of immune checkpoint inhibitors in a variety of cancers. The first in class approved immune checkpoint inhibitor is ipilimumab, an anti-CTLA-4 (cytotoxic T lymphocyte antigen-4) mAb. Two pivotal phase III randomized controlled trials demonstrated a survival benefit in patients with metastatic melanoma. In 2011, the US Food and Drug Administration (FDA) approved ipilimumab for metastatic melanoma. Several clinical trials have since investigated new agents, alone and in combination, for various cancers. In this review, we discuss the current development status of and future challenges in utilizing immune checkpoint inhibitors. PMID:26161407

  10. Clinical Development of Immune Checkpoint Inhibitors

    PubMed Central

    Ito, Ayumu; Kondo, Shunsuke; Tada, Kohei; Kitano, Shigehisa

    2015-01-01

    Recent progress in cancer immunotherapy has been remarkable. Most striking are the clinical development and approval of immunomodulators, also known as immune checkpoint inhibitors. These monoclonal antibodies (mAb) are directed to immune checkpoint molecules, which are expressed on immune cells and mediate signals to attenuate excessive immune reactions. Although mAbs targeting tumor associated antigens, such as anti-CD20 mAb and anti-Her2 mAb, directly recognize tumor cells and induce cell death, immune checkpoint inhibitors restore and augment the antitumor immune activities of cytotoxic T cells by blocking immune checkpoint molecules on T cells or their ligands on antigen presenting and tumor cells. Based on preclinical data, many clinical trials have demonstrated the acceptable safety profiles and efficacies of immune checkpoint inhibitors in a variety of cancers. The first in class approved immune checkpoint inhibitor is ipilimumab, an anti-CTLA-4 (cytotoxic T lymphocyte antigen-4) mAb. Two pivotal phase III randomized controlled trials demonstrated a survival benefit in patients with metastatic melanoma. In 2011, the US Food and Drug Administration (FDA) approved ipilimumab for metastatic melanoma. Several clinical trials have since investigated new agents, alone and in combination, for various cancers. In this review, we discuss the current development status of and future challenges in utilizing immune checkpoint inhibitors. PMID:26161407

  11. Inhibitors of the Metalloproteinase Anthrax Lethal Factor.

    PubMed

    Goldberg, Allison B; Turk, Benjamin E

    2016-01-01

    Bacillus anthracis, a rod shaped, spore forming, gram positive bacteria, is the etiological agent of anthrax. B. anthracis virulence is partly attributable to two secreted bipartite protein toxins, which act inside host cells to disrupt signaling pathways important for host defense against infection. These toxins may also directly contribute to mortality in late stage infection. The zinc-dependent metalloproteinase anthrax lethal factor (LF) is a critical component of one of these protein toxins and a prime target for inhibitor development to produce anthrax therapeutics. Here, we describe recent efforts to identify specific and potent LF inhibitors. Derivatization of peptide substrate analogs bearing zinc-binding groups has produced potent and specific LF inhibitors, and X-ray crystallography of LFinhibitor complexes has provided insight into features required for high affinity binding. Novel inhibitor scaffolds have been identified through several approaches, including fragment-based drug discovery, virtual screening, and highthroughput screening of diverse compound libraries. Lastly, efforts to discover LF inhibitors have led to the development of new screening strategies, such as the use of full-length proteins as substrates, that may prove useful for other proteases as well. Overall, these efforts have led to a collection of chemically and mechanistically diverse molecules capable of inhibiting LF activity in vitro and in cells, as well as in animal models of anthrax infection. PMID:27072692

  12. Monoamine Reuptake Inhibitors in Parkinson's Disease

    PubMed Central

    Huot, Philippe; Fox, Susan H.; Brotchie, Jonathan M.

    2015-01-01

    The motor manifestations of Parkinson's disease (PD) are secondary to a dopamine deficiency in the striatum. However, the degenerative process in PD is not limited to the dopaminergic system and also affects serotonergic and noradrenergic neurons. Because they can increase monoamine levels throughout the brain, monoamine reuptake inhibitors (MAUIs) represent potential therapeutic agents in PD. However, they are seldom used in clinical practice other than as antidepressants and wake-promoting agents. This review article summarises all of the available literature on use of 50 MAUIs in PD. The compounds are divided according to their relative potency for each of the monoamine transporters. Despite wide discrepancy in the methodology of the studies reviewed, the following conclusions can be drawn: (1) selective serotonin transporter (SERT), selective noradrenaline transporter (NET), and dual SERT/NET inhibitors are effective against PD depression; (2) selective dopamine transporter (DAT) and dual DAT/NET inhibitors exert an anti-Parkinsonian effect when administered as monotherapy but do not enhance the anti-Parkinsonian actions of L-3,4-dihydroxyphenylalanine (L-DOPA); (3) dual DAT/SERT inhibitors might enhance the anti-Parkinsonian actions of L-DOPA without worsening dyskinesia; (4) triple DAT/NET/SERT inhibitors might exert an anti-Parkinsonian action as monotherapy and might enhance the anti-Parkinsonian effects of L-DOPA, though at the expense of worsening dyskinesia. PMID:25810948

  13. Localization and distribution of tissue type and urokinase type plasminogen activators and their inhibitors Type 1 and 2 in human and rhesus monkey fetal membranes.

    PubMed

    Liu, Y X; Hu, Z Y; Liu, K; Byrne, S; Zou, R J; Ny, T; d'Lacey, C; Ockleford, C D

    1998-01-01

    in the level of abscission. No detectable amount of mRNAs for tPA, uPA, PAI-1 and PAI-2 was found in the fibroblast, reticular and spongy layers. Distribution of the proteins of tPA, uPA and PAI-1 in the fetal membranes of these two species was consistent with the distribution of their mRNA. Anti-PAI-2 immunofluorescence was found to be strongly concentrated in the amniotic epithelium, but PAI-2 mRNA was negative in this layer, suggesting that the epithelium-associated PAI-2 is not of epithelial origin. These findings suggest that a local fibrinolysis in fetal membranes generated by precisely balanced expression of PAs and their inhibitors via paracrine or autocrine mechanisms may play an essential role in fetal membrane development, maturation and in membrane rupture. Following an analysis of the distribution and synthesis of activators and inhibitors it was found that they may play a role in abscission during the third stage of labour. PMID:9548184

  14. Prehospital Resuscitation of Traumatic Hemorrhagic Shock with Hypertonic Solutions Worsens Hypocoagulation and Hyperfibrinolysis.

    PubMed

    Delano, Matthew J; Rizoli, Sandro B; Rhind, Shawn G; Cuschieri, Joseph; Junger, Wolfgang; Baker, Andrew J; Dubick, Michael A; Hoyt, David B; Bulger, Eileen M

    2015-07-01

    Impaired hemostasis frequently occurs after traumatic shock and resuscitation. The prehospital fluid administered can exacerbate subsequent bleeding and coagulopathy. Hypertonic solutions are recommended as first-line treatment of traumatic shock; however, their effects on coagulation are unclear. This study explores the impact of resuscitation with various hypertonic solutions on early coagulopathy after trauma. We conducted a prospective observational subgroup analysis of large clinical trial on out-of-hospital single-bolus (250 mL) hypertonic fluid resuscitation of hemorrhagic shock trauma patients (systolic blood pressure, ≤70 mmHg). Patients received 7.5% NaCl (HS), 7.5% NaCl/6% Dextran 70 (HSD), or 0.9% NaCl (normal saline [NS]) in the prehospital setting. Thirty-four patients were included: 9 HS, 8 HSD, 17 NS. Treatment with HS/HSD led to higher admission systolic blood pressure, sodium, chloride, and osmolarity, whereas lactate, base deficit, fluid requirement, and hemoglobin levels were similar in all groups. The HSD-resuscitated patients had higher admission international normalized ratio values and more hypocoagulable patients, 62% (vs. 55% HS, 47% NS; P < 0.05). Prothrombotic tissue factor was elevated in shock treated with NS but depressed in both HS and HSD groups. Fibrinolytic tissue plasminogen activator and anti-fibrinolytic plasminogen activator inhibitor type 1 were increased by shock but not thrombin-activatable fibrinolysis inhibitor. The HSD patients had the worst imbalance between procoagulation/anticoagulation and profibrinolysis/antifibrinolysis, resulting in more hypocoagulability and hyperfibrinolysis. We concluded that resuscitation with hypertonic solutions, particularly HSD, worsens hypocoagulability and hyperfibrinolysis after hemorrhagic shock in trauma through imbalances in both procoagulants and anticoagulants and both profibrinolytic and antifibrinolytic activities. PMID:25784523

  15. Novel hemagglutinin-based influenza virus inhibitors

    PubMed Central

    Shen, Xintian; Zhang, Xuanxuan

    2013-01-01

    Influenza virus has caused seasonal epidemics and worldwide pandemics, which caused tremendous loss of human lives and socioeconomics. Nowadays, only two classes of anti-influenza drugs, M2 ion channel inhibitors and neuraminidase inhibitors respectively, are used for prophylaxis and treatment of influenza virus infection. Unfortunately, influenza virus strains resistant to one or all of those drugs emerge frequently. Hemagglutinin (HA), the glycoprotein in influenza virus envelope, plays a critical role in viral binding, fusion and entry processes. Therefore, HA is a promising target for developing anti-influenza drugs, which block the initial entry step of viral life cycle. Here we reviewed recent understanding of conformational changes of HA in protein folding and fusion processes, and the discovery of HA-based influenza entry inhibitors, which may provide more choices for preventing and controlling potential pandemics caused by multi-resistant influenza viruses. PMID:23977436

  16. Functional non-nucleoside adenylyl cyclase inhibitors.

    PubMed

    Lelle, Marco; Hameed, Abdul; Ackermann, Lisa-Maria; Kaloyanova, Stefka; Wagner, Manfred; Berisha, Filip; Nikolaev, Viacheslav O; Peneva, Kalina

    2015-05-01

    In this study, we describe the synthesis of novel functional non-nucleoside adenylyl cyclase inhibitors, which can be easily modified with thiol containing biomolecules such as tumour targeting structures. The linkage between inhibitor and biomolecule contains cleavable bonds to enable efficient intracellular delivery in the reductive milieu of the cytosol as well as in the acidic environment within endosomes and lysosomes. The suitability of this synthetic approach was shown by the successful bioconjugation of a poor cell-permeable inhibitor with a cell-penetrating peptide. Additionally, we have demonstrated the excellent inhibitory effect of the compounds presented here in a live-cell Förster resonance energy transfer-based assay in human embryonic kidney cells. PMID:25319071

  17. Serotonin norepinephrine reuptake inhibitors: a pharmacological comparison.

    PubMed

    Sansone, Randy A; Sansone, Lori A

    2014-03-01

    The serotonin norepinephrine reuptake inhibitors are a family of antidepressants that inhibit the reuptake of both serotonin and norepinephrine. While these drugs are traditionally considered a group of inter-related antidepressants based upon reuptake inhibition, they generally display different chemical structures as well as different pharmacological properties. In this article, we discuss these and other differences among the serotonin norepinephrine reuptake inhibitors, including the year of approval by the United States Food and Drug Administration, generic availability, approved clinical indications, half-lives, metabolism and excretion, presence or not of active metabolites, dosing schedules, proportionate effects on serotonin and norepinephrine, and the timing of serotonin and norepinephrine reuptake (i.e., sequential or simultaneous). Again, while serotonin norepinephrine reuptake inhibitors are grouped as a family of antidepressants, they exhibit a surprising number of differences- differences that may ultimately relate to clinical nuances in patient care. PMID:24800132

  18. Topoisomerase I inhibitors: camptothecins and beyond.

    PubMed

    Pommier, Yves

    2006-10-01

    Nuclear DNA topoisomerase I (TOP1) is an essential human enzyme. It is the only known target of the alkaloid camptothecin, from which the potent anticancer agents irinotecan and topotecan are derived. As camptothecins bind at the interface of the TOP1-DNA complex, they represent a paradigm for interfacial inhibitors that reversibly trap macromolecular complexes. Several camptothecin and non-camptothecin derivatives are being developed to further increase anti-tumour activity and reduce side effects. The mechanisms and molecular determinants of tumour response to TOP1 inhibitors are reviewed, and rational combinations of TOP1 inhibitors with other drugs are considered based on current knowledge of repair and checkpoint pathways that are associated with TOP1-mediated DNA damage. PMID:16990856

  19. Orally Bioavailable Potent Soluble Epoxide Hydrolase Inhibitors

    PubMed Central

    Hwang, Sung Hee; Tsai, Hsing-Ju; Liu, Jun-Yan; Morisseau, Christophe; Hammock, Bruce D.

    2008-01-01

    A series of N,N′-disubstituted ureas having a conformationally restricted cis- or trans-1,4-cyclohexane α to the urea were prepared and tested as soluble epoxide hydrolase (sEH) inhibitors. This series of compounds showed low nanomolar to picomolar activities against recombinant human sEH. Both isomers showed similar potencies, but the trans isomers were more metabolically stable in human hepatic microsomes. Furthermore, these new potent inhibitors show a greater metabolic stability in vivo than previously described sEH inhibitors. We demonstrated that trans-4-[4-(3-adamantan-1-ylureido)cyclohexyloxy]benzoic acid 13g (t-AUCB, IC50 = 1.3 ± 0.05 nM) had excellent oral bioavailability (98%, n = 2) and blood area under the curve in dogs and was effective in vivo to treat hypotension in lipopolysaccharide challenged murine models. PMID:17616115

  20. Use of acetylcholinesterase inhibitors in Alzheimer's disease.

    PubMed

    Moghul, S; Wilkinson, D

    2001-09-01

    Alzheimer's disease is a growing problem in an aging Western world, estimated to have cost the US economy USD 1.75 trillion. Until recently, the management of Alzheimer's disease largely comprised support for the family, nursing care and the use of unlicensed medication to control behavioral disturbances. The three new acetylcholinesterase inhibitors licensed to treat Alzheimer's disease (donepezil, rivastigmine and galantamine) have provided clinicians with a major impetus to their desire to diagnose and treat this lethal disease. Their effects on cognition are proven. More recent work on the effects of acetylcholinesterase inhibitors on behavioral symptoms, activities of daily living and caregiver burden have also been encouraging. Emerging work indicates their likely efficacy in other dementias (e.g., vascular dementia, dementia with Lewy bodies). This review summarizes the evidence concerning the impact of acetylcholinesterase inhibitors in dementia both currently and over the next 5 years. PMID:19811047

  1. LDL cholesterol, statins and PCSK 9 inhibitors.

    PubMed

    Gupta, Sanjiv

    2015-01-01

    Reduction of low density lipoprotein cholesterol (LDLc) is of vital importance for the prevention of atherosclerotic cardiovascular disease (ASCVD). Statin is the most effective therapy today to lower LDLc by inhibiting HMG-CoA-reductase. However despite intensive statin therapy, there remains a residual risk of recurrent myocardial infarction in about 20-30% cases. Moreover a few patients develop statin intolerance. For severe hypercholesterolemia, statins alone or in combination of ezetimibe, niacin and fenofibrate have been advocated. For homozygous familial hypercholesterolemia (HOFH), a microsomal triglyceride transfer protein MTP inhibitor (Lopitamide) and antisense oligonucleotide (ASO) (Mipomersen) have recently been approved by FDA, USA through 'Risk evaluation and Mitigation Strategy (REMS)'. Possible future therapies include PCSK-9 inhibitors which have excellent lipid lowering properties. Three monoclonal antibodies (PCSK 9 Inhibitors) alirocumab, evolocumab and Bococizumab are under advanced clinical stage IV trials and awaiting approval by FDA and European Medicines Agency. PMID:26432726

  2. Synthesis of amino heterocycle aspartyl protease inhibitors.

    PubMed

    Chambers, Rachel K; Khan, Tanweer A; Olsen, David B; Sleebs, Brad E

    2016-06-14

    Aspartyl proteases are important pharmacological targets. Historically aspartyl proteases have been commonly targeted with transition state derived peptidomimetics. The strategy to develop aspartyl protease inhibitors has undertaken a dramatic paradigm shift in the last 10 years. The pharmaceutical industry in 2005 disclosed several scaffolds or "head groups" that prompted the field to move beyond peptidomimetic derived inhibitors. Since the discovery of the first amino heterocycle aspartyl protease inhibitor, the amino hydantoin, industry and academia have positioned themselves for a foothold on the new molecular space, designing a variety of related "head groups". Both the design and synthetic efforts involved in constructing these scaffolds are varied and complex. Here we highlight the synthetic strategies used to access these amino heterocycle scaffolds. PMID:27143279

  3. Prospects for novel inhibitors of peptidoglycan transglycosylases

    PubMed Central

    Galley, Nicola F.; O’Reilly, Amy M.; Roper, David I.

    2014-01-01

    The lack of novel antimicrobial drugs under development coupled with the increasing occurrence of resistance to existing antibiotics by community and hospital acquired infections is of grave concern. The targeting of biosynthesis of the peptidoglycan component of the bacterial cell wall has proven to be clinically valuable but relatively little therapeutic development has been directed towards the transglycosylase step of this process. Advances towards the isolation of new antimicrobials that target transglycosylase activity will rely on the development of the enzymological tools required to identify and characterise novel inhibitors of these enzymes. Therefore, in this article, we review the assay methods developed for transglycosylases and review recent novel chemical inhibitors discovered in relation to both the lipidic substrates and natural product inhibitors of the transglycosylase step. PMID:24924926

  4. Global Metabolic Inhibitors of Sialyl- and Fucosyltransferases

    PubMed Central

    Rillahan, Cory D.; Antonopoulos, Aristotelis; Lefort, Craig T.; Sonon, Roberto; Azadi, Parastoo; Ley, Klaus; Dell, Anne; Haslam, Stuart M.; Paulson, James C.

    2012-01-01

    Despite the fundamental roles of sialyl- and fucosyltransferases in mammalian physiology, there are few pharmacological tools to manipulate their function in a cellular setting. Although fluorinated analogs of the donor substrates are well-established transition state inhibitors of these enzymes, they are not membrane permeable. By exploiting promiscuous monosaccharide salvage pathways, we show that fluorinated analogs of sialic acid and fucose can be taken up and metabolized to the desired donor substrate-based inhibitors inside the cell. Due to the existence of metabolic feedback loops, they also act to prevent the de novo synthesis of the natural substrates, resulting in a global, family-wide shutdown of sialyl- and/or fucosyltransferases and remodeling of cell surface glycans. As an example of the functional consequences, the inhibitors drastically reduce expression of the sialylated and fucosylated ligand Sialyl Lewis X on myeloid cells, resulting in loss of binding to selectins and impaired leukocyte rolling. PMID:22683610

  5. Therapeutic potential of monoacylglycerol lipase inhibitors.

    PubMed

    Mulvihill, Melinda M; Nomura, Daniel K

    2013-03-19

    Marijuana and aspirin have been used for millennia to treat a wide range of maladies including pain and inflammation. Both cannabinoids, like marijuana, that exert anti-inflammatory action through stimulating cannabinoid receptors, and cyclooxygenase (COX) inhibitors, like aspirin, that suppress pro-inflammatory eicosanoid production have shown beneficial outcomes in mouse models of neurodegenerative diseases and cancer. Both cannabinoids and COX inhibitors, however, have untoward effects that discourage their chronic usage, including cognitive deficits and gastrointestinal toxicity, respectively. Recent studies have uncovered that the serine hydrolase monoacylglycerol lipase (MAGL) links the endocannabinoid and eicosanoid systems together through hydrolysis of the endocannabinoid 2-arachidonoylglycerol (2-AG) to provide the major arachidonic acid (AA) precursor pools for pro-inflammatory eicosanoid synthesis in specific tissues. Studies in recent years have shown that MAGL inhibitors elicit anti-nociceptive, anxiolytic, and anti-emetic responses and attenuate precipitated withdrawal symptoms in addiction paradigms through enhancing endocannabinoid signaling. MAGL inhibitors have also been shown to exert anti-inflammatory action in the brain and protect against neurodegeneration through lowering eicosanoid production. In cancer, MAGL inhibitors have been shown to have anti-cancer properties not only through modulating the endocannabinoid-eicosanoid network, but also by controlling fatty acid release for the synthesis of protumorigenic signaling lipids. Thus, MAGL serves as a critical node in simultaneously coordinating multiple lipid signaling pathways in both physiological and disease contexts. This review will discuss the diverse (patho)physiological roles of MAGL and the therapeutic potential of MAGL inhibitors in treating a vast array of complex human diseases. PMID:23142242

  6. Substituted quinolines as noncovalent proteasome inhibitors.

    PubMed

    McDaniel, Tanner J; Lansdell, Theresa A; Dissanayake, Amila A; Azevedo, Lauren M; Claes, Jacob; Odom, Aaron L; Tepe, Jetze J

    2016-06-01

    Screening of a library of diverse heterocyclic scaffolds identified substituted quinolines as inhibitors of the human proteasome. The heterocyclic library was prepared via a novel titanium-catalyzed multicomponent coupling reaction, which rendered a diverse set of isoxazoles, pyrimidines, pyrroles, pyrazoles and quinolines. SAR of the parent lead compound indicated that hydrophobic residues on the benzo-moiety significantly improved potency. Lead compound 25 inhibits the chymotryptic-like proteolytic activity of the proteasome (IC50 5.4μM), representing a new class of nonpeptidic, noncovalent proteasome inhibitors. PMID:27112450

  7. Selective serotonin reuptake inhibitor discontinuation during pregnancy

    PubMed Central

    Ejaz, Resham; Leibson, Tom; Koren, Gideon

    2014-01-01

    Abstract Question I have a patient who discontinued her selective serotonin reuptake inhibitor in pregnancy against my advice owing to fears it might affect the baby. She eventually attempted suicide. How can we deal effectively with this situation? Answer The “cold turkey” discontinuation of needed antidepressants is a serious public health issue strengthened by fears and misinformation. It is very important for physicians to ensure that evidence-based information is given to women in a way that is easy to understand. The risks of untreated moderate to severe depression far outweigh the theoretical risks of taking selective serotonin reuptake inhibitors. PMID:25642484

  8. Hereditary angioedema with normal C1 inhibitor.

    PubMed

    Bork, Konrad

    2013-11-01

    Until recently it was assumed that hereditary angioedema was a disease that results exclusively from a genetic deficiency of the C1 inhibitor. In 2000, families with hereditary angioedema, normal C1 inhibitor activity, and protein in plasma were described. Since then, numerous patients and families with that condition have been reported. Most of the patients were women. In many of the affected women, oral contraceptives, hormone replacement therapy containing estrogens, and pregnancies triggered the clinical symptoms. In some families mutations in the coagulation factor XII (Hageman factor) gene were detected. PMID:24176211

  9. Identification of potent, selective KDM5 inhibitors.

    PubMed

    Gehling, Victor S; Bellon, Steven F; Harmange, Jean-Christophe; LeBlanc, Yves; Poy, Florence; Odate, Shobu; Buker, Shane; Lan, Fei; Arora, Shilpi; Williamson, Kaylyn E; Sandy, Peter; Cummings, Richard T; Bailey, Christopher M; Bergeron, Louise; Mao, Weifeng; Gustafson, Amy; Liu, Yichin; VanderPorten, Erica; Audia, James E; Trojer, Patrick; Albrecht, Brian K

    2016-09-01

    This communication describes the identification and optimization of a series of pan-KDM5 inhibitors derived from compound 1, a hit initially identified against KDM4C. Compound 1 was optimized to afford compound 20, a 10nM inhibitor of KDM5A. Compound 20 is highly selective for the KDM5 enzymes versus other histone lysine demethylases and demonstrates activity in a cellular assay measuring the increase in global histone 3 lysine 4 tri-methylation (H3K4me3). In addition compound 20 has good ADME properties, excellent mouse PK, and is a suitable starting point for further optimization. PMID:27476424

  10. HIV Entry Inhibitors and Their Potential in HIV Therapy

    PubMed Central

    Qian, Keduo; Morris-Natschke, Susan L.; Lee, Kuo-Hsiung

    2013-01-01

    This review discusses recent progress in the development of anti-HIV agents targeting the viral entry process. The three main classes (attachment inhibitors, co-receptor binding inhibitors, and fusion inhibitors) are further broken down by specific mechanism of action and structure. Many of these inhibitors are in advanced clinical trials, including the HIV maturation inhibitor bevirimat, from the authors’ laboratories. In addition, the CCR5 inhibitor maraviroc has recently been FDA-approved. Possible roles for these agents in anti-HIV therapy, including treatment of virus resistant to current drugs, are also discussed. PMID:18720513

  11. Polyphenolic Compounds as Pancreatic Lipase Inhibitors.

    PubMed

    Buchholz, Tina; Melzig, Matthias F

    2015-07-01

    Obesity and its associated diseases such as diabetes mellitus and coronary heart diseases are a major challenge for our society. An important target for the treatment of obesity includes the development of inhibitors of nutrient digestion and absorption. Inhibition of pancreatic lipase and the associated reduction of lipid absorption is an attractive approach for the discovery of potent agents. Currently, the only clinically approved pharmacologic agent as pancreatic lipase inhibitor is Orlistat. However, its usage is compromised by unpleasant gastrointestinal adverse reactions (oily stools, oily spotting, flatulence). The use of botanical materials as a potential source of new drugs is of increasing importance and application. Natural products that are interesting for obesity treatment are generally considered to have less toxic and side effects than totally synthetic drugs. One of the most important sources of potential pancreatic lipase inhibitors represents the class of polyphenols. This article summarizes most studied subclasses of polyphenols including flavonoids, hydroxycinnamic acids, hydroxybenzoic acids and lignans with pancreatic lipase inhibitory effects. A structural comparison of potent inhibitors shows an increased inhibitory effect depending on number and position of phenolic hydroxyl groups, degree of polymerization and elimination of glycosylation during digestion. PMID:26132857

  12. Novel proteinase inhibitor promotes resistance to insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel Beta vulgaris serine proteinase inhibitor gene (BvSTI) and its protein are identified in response to insect feeding on B. vulgaris seedlings. BvSTI is cloned into an expression vector with constitutive promoter and transformed into Nicotiana benthamiana plants to assess BvSTI’s ability to ...

  13. Cardiovascular effects of dipeptidyl peptidase-4 inhibitors

    PubMed Central

    Papagianni, M; Tziomalos, K

    2015-01-01

    Dipeptidyl peptidase-4 (DPP-4) inhibitors are effective glucose-lowering agents that do not increase body weight and are associated with a low risk for hypoglycemia. Also, they appear to exert beneficial effects on other established cardiovascular risk factors, including dyslipidemia and hypertension. Moreover, DPP-4 inhibitors exert antiinflammatory and antioxidant actions, improve endothelial function and reduce urinary albumin excretion. In contrast to these favorable cardiovascular effects, three recent large, randomized, placebo-controlled trials in patients with type 2 diabetes mellitus (T2DM) and established cardiovascular disease or multiple cardiovascular risk factors showed that DPP-4 inhibitors do not affect the risk of myocardial infarction or ischemic stroke and might increase the risk of heart failure. The findings of the former randomized studies highlight the limitations of surrogate markers and show that beneficial effects on cardiovascular risk factors do not necessarily translate into reductions in hard clinical endpoints. Ongoing trials will shed more light on the safety profile of DPP-4 inhibitors and will clarify whether they will improve the cardiovascular outcomes of patients with T2DM. Hippokratia 2015; 19 (3): 195-199. PMID:27418775

  14. Histidines, histamines and imidazoles as glycosidase inhibitors.

    PubMed Central

    Field, R A; Haines, A H; Chrystal, E J; Luszniak, M C

    1991-01-01

    This present study reports the ability of a range of derivatives of L-histidine, histamine and imidazole to act as inhibitors of sweet-almond beta-glucosidase, yeast alpha-glucosidase and Escherichia coli beta-galactosidase. The addition of a hydrophobic group to the basic imidazole nucleus greatly enhances binding to both the alpha- and beta-glucosidases. L-Histidine (beta-naphthylamide (Ki 17 microM) is a potent competitive inhibitor of sweet-almond beta-glucosidase as is omega-N-acetylhistamine (K1 35 microM), which inhibits the sweet-almond beta-glucosidase at least 700 times more strongly than either yeast alpha-glucosidase or Escherichia coli beta-galactosidase, and suggests potential for the development of selective reversible beta-glucosidase inhibitors. A range of hydrophobic omega-N-acylhistamines were synthesized and shown to be among the most potent inhibitors of sweet-almond beta-glucosidase reported to date. PMID:2012615

  15. A chemotactic inhibitor in synovial fluid.

    PubMed Central

    Matzner, Y; Partridge, R E; Babior, B M

    1983-01-01

    Synovial fluid was found to contain an inhibitor of neutrophil chemotaxis. The activity of this inhibitor was masked in native synovial fluid, but could be detected in fluid in which complement had been deactivated by mild heating. The inhibitor was most effective against the chemotactic activity of zymosan-activated serum (C5ades arg). It had little effect when N-formyl-methionyl-leucyl-phenylalanine served as chemoattractant. Inhibition was not the result of a direct effect on the neutrophils, since incubation of cells with synovial fluid did not alter their chemotactic response. The inhibitory activity was destroyed by boiling the synovial fluid or treating it with trypsin, suggesting that it is a protein (or proteins); it was not affected by hyaluronidase treatment. Gel filtration revealed that the inhibitor was present in native as well as decomplemented synovial fluid, and that its molecular weight was in the vicinity of 25,000. It is proposed that this inhibitory activity plays a role in the regulation of the inflammatory response in joints. PMID:6840801

  16. Resistant mechanisms to BRAF inhibitors in melanoma.

    PubMed

    Manzano, José Luís; Layos, Laura; Bugés, Cristina; de Los Llanos Gil, María; Vila, Laia; Martínez-Balibrea, Eva; Martínez-Cardús, Anna

    2016-06-01

    Patients with advanced melanoma have traditionally had very poor prognosis. However, since 2011 better understanding of the biology and epidemiology of this disease has revolutionized its treatment, with newer therapies becoming available. These newer therapies can be classified into immunotherapy and targeted therapy. The immunotherapy arsenal includes inhibitors of CTLA4, PD-1 and PDL-1, while targeted therapy focuses on BRAF and MEK. BRAF inhibitors (vemurafenib, dabrafenib) have shown benefit in terms of overall survival (OS) compared to chemotherapy, and their combination with MEK inhibitors has recently been shown to improve progression-free survival (PFS), compared with monotherapy with BRAF inhibitors. However, almost 20% of patients initially do not respond, due to intrinsic resistance to therapy and, of those who do, most eventually develop mechanisms of acquired resistance, including reactivation of the MAP kinase pathway, persistent activation of receptor tyrosine kinase (RTKS) receptor, activation of phosphatidyinositol-3OH kinase, overexpression of epidermal growth factor receptor (EGFR), and interactions with the tumor microenvironment. Herein we comment in detail on mechanisms of resistance to targeted therapy and discuss the strategies to overcome them. PMID:27429963

  17. Cellulose biosynthesis inhibitors - a multifunctional toolbox.

    PubMed

    Tateno, Mizuki; Brabham, Chad; DeBolt, Seth

    2016-01-01

    In the current review, we examine the growing number of existing Cellulose Biosynthesis Inhibitors (CBIs) and based on those that have been studied with live cell imaging we group their mechanism of action. Attention is paid to the use of CBIs as tools to ask fundamental questions about cellulose biosynthesis. PMID:26590309

  18. FAAH inhibitors in the limelight, but regrettably

    PubMed Central

    Mallet, Christophe; Dubray, Claude; Dualé, Christian

    2016-01-01

    Abstract. This short review focuses on the recent drug development of FAAH inhibitors, as recent serious adverse events have been reported in a phase I study with a compound of this class. The authors overview the potential interest in targeting FAAH inhibition, the current programs, and the available information on the recent dramatic events. PMID:27191771

  19. Phenyltriazolinones as potent factor Xa inhibitors.

    PubMed

    Quan, Mimi L; Pinto, Donald J P; Rossi, Karen A; Sheriff, Steven; Alexander, Richard S; Amparo, Eugene; Kish, Kevin; Knabb, Robert M; Luettgen, Joseph M; Morin, Paul; Smallwood, Angela; Woerner, Francis J; Wexler, Ruth R

    2010-02-15

    We have discovered that phenyltriazolinone is a novel and potent P1 moiety for coagulation factor Xa. X-ray structures of the inhibitors with a phenyltriazolinone in the P1 position revealed that the side chain of Asp189 has reoriented resulting in a novel S1 binding pocket which is larger in size to accommodate the phenyltriazolinone P1 substrate. PMID:20100660

  20. Photodynamic therapy using a protoporphyrinogen oxidase inhibitor.

    PubMed

    Fingar, V H; Wieman, T J; McMahon, K S; Haydon, P S; Halling, B P; Yuhas, D A; Winkelman, J W

    1997-10-15

    The use of endogenously created porphyrins as an alternative to photosensitizer injection for photodynamic therapy is a rapidly evolving area of study. One common method to induce porphyrin synthesis and accumulation in cells is the topical, oral, or parenteral administration of 5-aminolevulinic acid, a precursor for heme biosynthesis. Porphyrin accumulation may also be elicited by the use of enzyme inhibitors of the heme biosynthetic pathway. Groups of DBA/2 mice bearing SMT-F mammary tumors were placed on a diet containing 0-4000 ppm of a protoporphyrinogen oxidase inhibitor, FP-846. This agent blocks a critical step in porphyrin metabolism and results in elevated intracellular levels of protoporphyrin IX. Light treatment of tumors produced both initial and long-term regression that was dependent on the amount of inhibitor, the duration of inhibitor exposure to animals, and the amount of light used in PDT. Tumor regression occurred without significant destruction of normal tissues in the treatment field and without initial vascular constriction or blood flow stasis. Tumor cure in animals given 4000 ppm FP-846 in feed for 3 days and 300 J/cm2 602-670 nm light (23% cure) was similar to the response in animals given 10 mg/kg Photofrin and the same light dose (20%). PMID:9377568

  1. Resistant mechanisms to BRAF inhibitors in melanoma

    PubMed Central

    Layos, Laura; Bugés, Cristina; de los Llanos Gil, María; Vila, Laia; Martínez-Balibrea, Eva; Martínez-Cardús, Anna

    2016-01-01

    Patients with advanced melanoma have traditionally had very poor prognosis. However, since 2011 better understanding of the biology and epidemiology of this disease has revolutionized its treatment, with newer therapies becoming available. These newer therapies can be classified into immunotherapy and targeted therapy. The immunotherapy arsenal includes inhibitors of CTLA4, PD-1 and PDL-1, while targeted therapy focuses on BRAF and MEK. BRAF inhibitors (vemurafenib, dabrafenib) have shown benefit in terms of overall survival (OS) compared to chemotherapy, and their combination with MEK inhibitors has recently been shown to improve progression-free survival (PFS), compared with monotherapy with BRAF inhibitors. However, almost 20% of patients initially do not respond, due to intrinsic resistance to therapy and, of those who do, most eventually develop mechanisms of acquired resistance, including reactivation of the MAP kinase pathway, persistent activation of receptor tyrosine kinase (RTKS) receptor, activation of phosphatidyinositol-3OH kinase, overexpression of epidermal growth factor receptor (EGFR), and interactions with the tumor microenvironment. Herein we comment in detail on mechanisms of resistance to targeted therapy and discuss the strategies to overcome them. PMID:27429963

  2. [Myoclonic encephalopathy associated with proton pump inhibitors].

    PubMed

    Boulliat, J; Polard, E; Colin, F; Bentué-Ferrer, D; Allain, H

    2004-03-01

    Two men (66 and 73 Years) with a cardiovascular history were hospitalized for rapid onset encephalopathy associated with myoclonia and an extrapyramidal syndrome. On the basis of the French Pharmacovigilance system, this symptomatology has been attributed to the coadministration of a proton pump inhibitor, lansoprazole (15mg/day) with levodopa. Lansoprazole withdrawal led to a normalisation of the situation. PMID:15037850

  3. Novel in vitro inhibitory functions of potato tuber proteinaceous inhibitors.

    PubMed

    Fischer, Matthias; Kuckenberg, Markus; Kastilan, Robin; Muth, Jost; Gebhardt, Christiane

    2015-02-01

    Plant protease inhibitors are a structurally highly diverse and ubiquitous class of small proteins, which play various roles in plant development and defense against pests and pathogens. Particular isoforms inhibit in vitro proteases and other enzymes that are not their natural substrates, for example proteases that have roles in human diseases. Mature potato tubers are a rich source of several protease inhibitor families. Different cultivars have different inhibitor profiles. With the objective to explore the functional diversity of the natural diversity of potato protease inhibitors, we randomly selected and sequenced 9,600 cDNA clones originated from mature tubers of ten potato cultivars. Among these, 120 unique inhibitor cDNA clones were identified by homology searches. Eighty-eight inhibitors represented novel sequence variants of known plant protease inhibitor families. Most frequent were Kunitz-type inhibitors (KTI), potato protease inhibitors I and II (PIN), pectin methylesterase inhibitors, metallocarboxypeptidase inhibitors and defensins. Twenty-three inhibitors were functionally characterized after heterologous expression in the yeast Pichia pastoris. The purified recombinant proteins were tested for inhibitory activity on trypsin, eleven pharmacological relevant proteases and the non-proteolytic enzyme 5-lipoxygenase. Members of the KTI and PIN families inhibited pig pancreas elastase, β-Secretase, Cathepsin K, HIV-1 protease and potato 5-lipoxygenase. Our results demonstrate in vitro inhibitory diversity of small potato tuber proteins commonly known as protease inhibitors, which might have biotechnological or medical applications. PMID:25260821

  4. Cost of care of haemophilia with inhibitors.

    PubMed

    Di Minno, M N D; Di Minno, G; Di Capua, M; Cerbone, A M; Coppola, A

    2010-01-01

    In Western countries, the treatment of patients with inhibitors is presently the most challenging and serious issue in haemophilia management, direct costs of clotting factor concentrates accounting for >98% of the highest economic burden absorbed for the healthcare of patients in this setting. Being designed to address questions of resource allocation and effectiveness, decision models are the golden standard to reliably assess the overall economic implications of haemophilia with inhibitors in terms of mortality, bleeding-related morbidity, and severity of arthropathy. However, presently, most data analyses stem from retrospective short-term evaluations, that only allow for the analysis of direct health costs. In the setting of chronic diseases, the cost-utility analysis, that takes into account the beneficial effects of a given treatment/healthcare intervention in terms of health-related quality of life, is likely to be the most appropriate approach. To calculate net benefits, the quality adjusted life year, that significantly reflects such health gain, has to be compared with specific economic impacts. Differences in data sources, in medical practice and/or in healthcare systems and costs, imply that most current pharmacoeconomic analyses are confined to a narrow healthcare payer perspective. Long-term/lifetime prospective or observational studies, devoted to a careful definition of when to start a treatment; of regimens (dose and type of product) to employ, and of inhibitor population (children/adults, low-responding/high responding inhibitors) to study, are thus urgently needed to allow for newer insights, based on reliable data sources into resource allocation, effectiveness and cost-utility analysis in the treatment of haemophiliacs with inhibitors. PMID:19845772

  5. Inhibitors from Carob (Ceratonia siliqua L.)

    PubMed Central

    Corcoran, Mary Ritzel

    1970-01-01

    Two inhibitory fractions (B1 and C) from extracts of immature fruit of carob were tested for their ability to inhibit the action of indoleacetic acid (IAA) in three bioassays. There was no reduction of IAA-induced reactions in the Avena curvature test, abscission of debladed coleus petioles, or growth of cucumber hypocotyls. The highest ratio of inhibitor to IAA was 10,000 times greater than the ratio necessary to inhibit by 50% the growth caused by an equivalent amount of gibberellin A3 in pea seedlings. At the highest concentration used, fraction C alone caused curvature of Avena coleoptiles. The inhibitory fractions appeared to enhance the effect of IAA in the cucumber test. Concentrated whole extract and fractions B1 and C were tested for reduction of growth caused by gibberellins A1, A4, A5, A7, and a neutral gibberellin-like substance from beans in the dwarf-5 maize bioassay. Each gibberellin was inhibited and required the same amount of inhibitor for a 50% reduction of the induced growth. The inhibiting effect could be completely overcome by increasing the amount of gibberellin while maintaining the same concentration of inhibitor. Fractions B1 and C were also tested with gibberellins A2 and A4 in the cucumber hypocotyl test. Both inhibitory fractions reduced growth but were more effective against gibberellin A3 than gibberellin A4 in the assay. The ability to reduce gibberellin-induced growth and not reduce IAA-induced growth indicates that the inhibitors from carob have a greater specificity of action than that previously reported for any inhibitor. PMID:16657500

  6. DNA Methyltransferases Inhibitors from Natural Sources.

    PubMed

    Zwergel, Clemens; Valente, Sergio; Mai, Antonello

    2016-01-01

    DNA methyltransferases (DNMTs) catalyze the methylation at cytosine-C5 mainly in a CpG dinucleotide context. Although DNA methylation is essential for fundamental processes like embryonic development or differentiation, aberrant expression and/or activities of DNMTs are involved in several pathologies, from neurodegeneration to cancer. DNMTs inhibition can arrest tumor growth, cells invasiveness and induce differentiation, whereas their increased expression is shown in numerous cancer types. Moreover, hypermethylated promoters of tumor suppressor genes lead to their silencing. Hence, the use of specific inhibitors of DNMT might reactivate those genes and stop or even reverse the aberrant cell processes. To date, the only approved DNMTs inhibitors for therapy belong to the nucleoside-based family of drugs, but they display relevant side effects as well as high chemical instability. Thus, there is a keen interest actually exists to develop novel, potent and safe inhibitors possessing a nonnucleoside structure. Increasing literature evidence is highlighting that natural sources could help the researchers to achieve this goal. Indeed, several polyphenols, flavonoids, antraquinones, and others are described able to inhibit DNMTs activity and/or expression, thus decreasing the methylation/silencing of different genes involved in tumorigenesis. These events can lead to re-expression of such genes and to cell death in diverse cancer cell lines. Epigallocatechin-3-gallate (1) and laccaic acid A (11) resulted the most effective DNMT1 inhibitors with submicromolar IC50 values, acting as competitive inhibitors. Compound 1 and 11 both displayed gene demethylation and re-activation in several cancers. However, all of the natural compounds described in this review showed important results, from gene reactivation to cell growth inhibition. Moreover, some of them displayed interesting activity even in rodent cancer models and very recently entered clinical trials. PMID:26303417

  7. Peptidyl cyclopropenones: Reversible inhibitors, irreversible inhibitors, or substrates of cysteine proteases?

    PubMed Central

    Cohen, Meital; Bretler, Uriel; Albeck, Amnon

    2013-01-01

    Peptidyl cyclopropenones were previously introduced as selective cysteine protease reversible inhibitors. In the present study we synthesized one such peptidyl cyclopropenone and investigated its interaction with papain, a prototype cysteine protease. A set of kinetics, biochemical, HPLC, MS, and 13C-NMR experiments revealed that the peptidyl cyclopropenone was an irreversible inhibitor of the enzyme, alkylating the catalytic cysteine. In parallel, this cyclopropenone also behaved as an alternative substrate of the enzyme, providing a product that was tentatively suggested to be either a spiroepoxy cyclopropanone or a gamma-lactone. Thus, a single family of compounds exhibits an unusual variety of activities, being reversible inhibitors, irreversible inhibitors and alternative substrates towards enzymes of the same family. PMID:23553793

  8. Comparative study on the protease inhibitors from fish eggs

    NASA Astrophysics Data System (ADS)

    Ustadi; Kim, K. Y.; Kim, S. M.

    2005-07-01

    The protease inhibitor was purified from five different fish eggs. The molecular weights of Pacific herring, chum salmon, pond smelt, glassfish, and Alaska pollock egg protease inhibitors were 120, 89, 84.5, 17, and l6.8kDa, respectively. The specific inhibitory activity of glassfish egg protease inhibitor was the highest followed by those of Pacific herring and Alaska pollock in order. The specific inhibitory activity and purity of glassfish egg protease inhibitor were 19.70 Umg-1 protein and 164.70 folds of purification, respectively. Glassfish egg protease inhibitor was reasonably stable at 50-65°C and pH 8, which was more stable at high temperature and pH than protease inhibitors from the other fish species. Glassfish egg protease inhibitor was noncompetitive with inhibitor constant ( K i) of 4.44 nmolL-1.

  9. ROS inhibitor N-acetyl-L-cysteine antagonizes the activity of proteasome inhibitors.

    PubMed

    Halasi, Marianna; Wang, Ming; Chavan, Tanmay S; Gaponenko, Vadim; Hay, Nissim; Gartel, Andrei L

    2013-09-01

    NAC (N-acetyl-L-cysteine) is commonly used to identify and test ROS (reactive oxygen species) inducers, and to inhibit ROS. In the present study, we identified inhibition of proteasome inhibitors as a novel activity of NAC. Both NAC and catalase, another known scavenger of ROS, similarly inhibited ROS levels and apoptosis associated with H₂O₂. However, only NAC, and not catalase or another ROS scavenger Trolox, was able to prevent effects linked to proteasome inhibition, such as protein stabilization, apoptosis and accumulation of ubiquitin conjugates. These observations suggest that NAC has a dual activity as an inhibitor of ROS and proteasome inhibitors. Recently, NAC was used as a ROS inhibitor to functionally characterize a novel anticancer compound, piperlongumine, leading to its description as a ROS inducer. In contrast, our own experiments showed that this compound depicts features of proteasome inhibitors including suppression of FOXM1 (Forkhead box protein M1), stabilization of cellular proteins, induction of ROS-independent apoptosis and enhanced accumulation of ubiquitin conjugates. In addition, NAC, but not catalase or Trolox, interfered with the activity of piperlongumine, further supporting that piperlongumine is a proteasome inhibitor. Most importantly, we showed that NAC, but not other ROS scavengers, directly binds to proteasome inhibitors. To our knowledge, NAC is the first known compound that directly interacts with and antagonizes the activity of proteasome inhibitors. Taken together, the findings of the present study suggest that, as a result of the dual nature of NAC, data interpretation might not be straightforward when NAC is utilized as an antioxidant to demonstrate ROS involvement in drug-induced apoptosis. PMID:23772801

  10. Development of covalent inhibitors that can overcome resistance to first-generation FGFR kinase inhibitors.

    PubMed

    Tan, Li; Wang, Jun; Tanizaki, Junko; Huang, Zhifeng; Aref, Amir R; Rusan, Maria; Zhu, Su-Jie; Zhang, Yiyun; Ercan, Dalia; Liao, Rachel G; Capelletti, Marzia; Zhou, Wenjun; Hur, Wooyoung; Kim, NamDoo; Sim, Taebo; Gaudet, Suzanne; Barbie, David A; Yeh, Jing-Ruey Joanna; Yun, Cai-Hong; Hammerman, Peter S; Mohammadi, Moosa; Jänne, Pasi A; Gray, Nathanael S

    2014-11-11

    The human FGF receptors (FGFRs) play critical roles in various human cancers, and several FGFR inhibitors are currently under clinical investigation. Resistance usually results from selection for mutant kinases that are impervious to the action of the drug or from up-regulation of compensatory signaling pathways. Preclinical studies have demonstrated that resistance to FGFR inhibitors can be acquired through mutations in the FGFR gatekeeper residue, as clinically observed for FGFR4 in embryonal rhabdomyosarcoma and neuroendocrine breast carcinomas. Here we report on the use of a structure-based drug design to develop two selective, next-generation covalent FGFR inhibitors, the FGFR irreversible inhibitors 2 (FIIN-2) and 3 (FIIN-3). To our knowledge, FIIN-2 and FIIN-3 are the first inhibitors that can potently inhibit the proliferation of cells dependent upon the gatekeeper mutants of FGFR1 or FGFR2, which confer resistance to first-generation clinical FGFR inhibitors such as NVP-BGJ398 and AZD4547. Because of the conformational flexibility of the reactive acrylamide substituent, FIIN-3 has the unprecedented ability to inhibit both the EGF receptor (EGFR) and FGFR covalently by targeting two distinct cysteine residues. We report the cocrystal structure of FGFR4 with FIIN-2, which unexpectedly exhibits a "DFG-out" covalent binding mode. The structural basis for dual FGFR and EGFR targeting by FIIN3 also is illustrated by crystal structures of FIIN-3 bound with FGFR4 V550L and EGFR L858R. These results have important implications for the design of covalent FGFR inhibitors that can overcome clinical resistance and provide the first example, to our knowledge, of a kinase inhibitor that covalently targets cysteines located in different positions within the ATP-binding pocket. PMID:25349422

  11. Development of covalent inhibitors that can overcome resistance to first-generation FGFR kinase inhibitors

    PubMed Central

    Tan, Li; Wang, Jun; Tanizaki, Junko; Huang, Zhifeng; Aref, Amir R.; Rusan, Maria; Zhu, Su-Jie; Zhang, Yiyun; Ercan, Dalia; Liao, Rachel G.; Capelletti, Marzia; Zhou, Wenjun; Hur, Wooyoung; Kim, NamDoo; Sim, Taebo; Gaudet, Suzanne; Barbie, David A.; Yeh, Jing-Ruey Joanna; Yun, Cai-Hong; Hammerman, Peter S.; Mohammadi, Moosa; Jänne, Pasi A.; Gray, Nathanael S.

    2014-01-01

    The human FGF receptors (FGFRs) play critical roles in various human cancers, and several FGFR inhibitors are currently under clinical investigation. Resistance usually results from selection for mutant kinases that are impervious to the action of the drug or from up-regulation of compensatory signaling pathways. Preclinical studies have demonstrated that resistance to FGFR inhibitors can be acquired through mutations in the FGFR gatekeeper residue, as clinically observed for FGFR4 in embryonal rhabdomyosarcoma and neuroendocrine breast carcinomas. Here we report on the use of a structure-based drug design to develop two selective, next-generation covalent FGFR inhibitors, the FGFR irreversible inhibitors 2 (FIIN-2) and 3 (FIIN-3). To our knowledge, FIIN-2 and FIIN-3 are the first inhibitors that can potently inhibit the proliferation of cells dependent upon the gatekeeper mutants of FGFR1 or FGFR2, which confer resistance to first-generation clinical FGFR inhibitors such as NVP-BGJ398 and AZD4547. Because of the conformational flexibility of the reactive acrylamide substituent, FIIN-3 has the unprecedented ability to inhibit both the EGF receptor (EGFR) and FGFR covalently by targeting two distinct cysteine residues. We report the cocrystal structure of FGFR4 with FIIN-2, which unexpectedly exhibits a “DFG-out” covalent binding mode. The structural basis for dual FGFR and EGFR targeting by FIIN3 also is illustrated by crystal structures of FIIN-3 bound with FGFR4 V550L and EGFR L858R. These results have important implications for the design of covalent FGFR inhibitors that can overcome clinical resistance and provide the first example, to our knowledge, of a kinase inhibitor that covalently targets cysteines located in different positions within the ATP-binding pocket. PMID:25349422

  12. Combined effects of EGFR tyrosine kinase inhibitors and vATPase inhibitors in NSCLC cells.

    PubMed

    Jin, Hyeon-Ok; Hong, Sung-Eun; Kim, Chang Soon; Park, Jin-Ah; Kim, Jin-Hee; Kim, Ji-Young; Kim, Bora; Chang, Yoon Hwan; Hong, Seok-Il; Hong, Young Jun; Park, In-Chul; Lee, Jin Kyung

    2015-08-15

    Despite excellent initial clinical responses of non-small cell lung cancer (NSCLC) patients to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), many patients eventually develop resistance. According to a recent report, vacuolar H+ ATPase (vATPase) is overexpressed and is associated with chemotherapy drug resistance in NSCLC. We investigated the combined effects of EGFR TKIs and vATPase inhibitors and their underlying mechanisms in the regulation of NSCLC cell death. We found that combined treatment with EGFR TKIs (erlotinib, gefitinib, or lapatinib) and vATPase inhibitors (bafilomycin A1 or concanamycin A) enhanced synergistic cell death compared to treatments with each drug alone. Treatment with bafilomycin A1 or concanamycin A led to the induction of Bnip3 expression in an Hif-1α dependent manner. Knock-down of Hif-1α or Bnip3 by siRNA further enhanced cell death induced by bafilomycin A1, suggesting that Hif-1α/Bnip3 induction promoted resistance to cell death induced by the vATPase inhibitors. EGFR TKIs suppressed Hif-1α and Bnip3 expression induced by the vATPase inhibitors, suggesting that they enhanced the sensitivity of the cells to these inhibitors by decreasing Hif-1α/Bnip3 expression. Taken together, we conclude that EGFR TKIs enhance the sensitivity of NSCLC cells to vATPase inhibitors by decreasing Hif-1α/Bnip3 expression. We suggest that combined treatment with EGFR TKIs and vATPase inhibitors is potentially effective for the treatment of NSCLC. PMID:25981168

  13. Tissue factor pathway inhibitor-2 is a novel inhibitor of matrix metalloproteinases with implications for atherosclerosis

    PubMed Central

    Herman, Michael P.; Sukhova, Galina K.; Kisiel, Walter; Foster, Don; Kehry, Marilyn R.; Libby, Peter; Schönbeck, Uwe

    2001-01-01

    Degradation of ECM, particularly interstitial collagen, promotes plaque instability, rendering atheroma prone to rupture. Previous studies implicated matrix metalloproteinases (MMPs) in these processes, suggesting that dysregulated MMP activity, probably due to imbalance with endogenous inhibitors, promotes complications of atherosclerosis. We report here that the serine proteinase inhibitor tissue factor pathway inhibitor-2 (TFPI-2) can function as an MMP inhibitor. TFPI-2 diminished the ability of the interstitial collagenases MMP-1 and MMP-13 to degrade triple-helical collagen, the primary load-bearing molecule of the ECM within human atheroma. In addition, TFPI-2 also reduced the activity of the gelatinases MMP-2 and MMP-9. In contrast to the “classical” tissue inhibitors of MMPs (TIMPs), TFPI-2 expression in situ correlated inversely with MMP levels in human atheroma. TFPI-2 colocalized primarily with smooth muscle cells in the normal media as well as the plaque’s fibrous cap. Conversely, the macrophage-enriched shoulder region, the prototypical site of matrix degradation and plaque rupture, stained only weakly for TFPI-2 but intensely for gelatinases and interstitial collagenases. Evidently, human mononuclear phagocytes, an abundant source of MMPs within human atheroma, lost their ability to express this inhibitor during differentiation in vitro. These findings establish a new, anti-inflammatory function of TFPI-2 of potential pathophysiological significance for human diseases, including atherosclerosis. PMID:11342575

  14. Action of anti-HIV drugs and resistance: reverse transcriptase inhibitors and protease inhibitors.

    PubMed

    Imamichi, Tomozumi

    2004-01-01

    Currently, 20 drugs have been approved for Human Immunodeficiency Virus type-1 (HIV-1) clinical therapy. These drugs inhibit HIV-1 reverse transcriptase, protease, or virus entry. Introduction of a combination therapy with reverse transcriptase inhibitors and protease inhibitors has resulted in a drastic decrease in HIV-1 related mortality. Although the combination therapy can suppress viral replication below detection levels in current available assays, low levels of on-going viral replication still persist in some patients. Long-term administration of the combination therapy may increase selective pressure against viruses, and subsequently induce emergence of multiple drug-resistant HIV-1 variants. Attempts have been made to design novel antiretroviral drugs that would be able to suppress replication of the resistant variants. At present, several investigational drugs are being tested in clinical trials. These drugs target not only the resistant variants, but also improvement in oral bioavilability or other viral proteins such as HIV-1 integrase, ribonuclease H, and HIV-1 entry (CD4 attachment inhibitors, chemokine receptors antagonists, and fusion inhibitors). Understanding mechanism(s) of action of the drugs and mechanisms of drug resistance is necessary for successful designs in the next generation of anti-HIV-1 drugs. In this review, the mechanisms of action of reverse transcriptase- and protease-inhibitors, and the mechanism of resistance to these inhibitors, are described. PMID:15579086

  15. Disulfide bridge structure of ascidian trypsin inhibitor I: similarity to Kazal-type inhibitors.

    PubMed

    Kumazaki, T; Ishii, S

    1990-03-01

    The primary structures of ascidian trypsin inhibitors (iso-inhibitors I and II) were reported in the preceding paper (Kumazaki, T. et al. (1990) J. Biochem. 107, 409-413). Both of them have eight half-cystines in a molecule composed of 55 amino acid residues with a sequence showing no extensive homology to other known protease inhibitors. To locate the four disulfide bridges in the molecule, native inhibitor I was digested with thermolysin to yield cystine-containing peptides. The peptides were separated from each other by reversed-phase HPLC. A core peptide still containing six closely located half-cystines (e.g. -Cys-Arg-Cys and -Cys-Cys-) was further digested with Streptomyces griseus trypsin for cleavage of the Arg-Cys bond. On the other hand, the Cys-Cys bond was split by applying manual Edman degradation to the core peptide. Amino acid composition analyses of the resulting cystine peptides allowed us to define the whole disulfide bridge structure in the parent molecule. The topological relation between the disulfide loops and the reactive site suggested that the ascidian trypsin inhibitor may be classified as a member of the Kazal-type inhibitor family. PMID:2111316

  16. Studies on amylase inhibitors in some Egyptian legume seeds.

    PubMed

    Shekib, L A; el-Iraqui, S M; Abo-Bakr, T M

    1988-01-01

    Amylase inhibitor activity was determined in four legume seeds which are widely consumed in Egypt. The effect of dehulling, heat treatment, soaking and germination were also assessed. The results showed that faba bean contained the highest activity of amylase inhibitor followed by cowpea, lentils, then chickpea. Dehulling resulted in raising the amylase inhibitor activities in all samples investigated, while heat treatment and cooking lowered it. Soaking for 10 h and germination eliminated completely the inhibitor from all samples. PMID:2467277

  17. Controlled-release scale inhibitor for use in fracturing treatments

    SciTech Connect

    Powell, R.J.; Gdanski, R.D.; McCabe, M.A.; Buster, D.C.

    1995-11-01

    This paper describes results of laboratory and field testing of a solid, controlled-release scale inhibitor for use in fracturing treatments. Laboratory testing with a continuous flow apparatus has yielded inhibitor release rates under dynamic conditions. The inhibitor was tested to determine the minimum inhibitor concentration required to inhibit the formation of CaCO{sub 3}, CaSO{sub 4}, and BaSO{sub 4} scales in a brine. A model to predict the long-term release rate of the inhibitor was developed from data collected on the continuous flow apparatus. Data from treated wells will be compared with predictions of the model. Inhibitor release-rate testing in a continuous-flow apparatus shows that a solid, calcium-magnesium polyphosphate inhibitor has a sustained release profile. Release-rate testing shows that the inhibitor can be used up to 175 F. The inhibitor is compatible with both borate and zirconium crosslinked fracturing fluids and foamed fluids. The effective lifetime of the scale treatment can be predicted based on a model developed from laboratory data. The input variables required for the prediction include: temperature, water production, amount of inhibitor, minimum effective concentration of inhibitor for the specific brine. The model can be used to aid in the design of the scale inhibitor treatment.

  18. Inhibitor analysis for a solar heating and cooling system

    NASA Technical Reports Server (NTRS)

    Tabony, J. H.

    1977-01-01

    A study of potential corrosion inhibitors for the NASA solar heating and cooling system which uses aluminum solar panels is provided. Research consisted of testing using a dynamic corrosion system, along with an economic analysis of proposed corrosion inhibitors. Very good progress was made in finding a suitable inhibitor for the system.

  19. P3 SAR exploration of biphenyl carbamate based Legumain inhibitors.

    PubMed

    Higgins, Catherine; Bouazzaoui, Samira; Gaddale, Kishore; D'Costa, Zenobia; Templeman, Amy; O'Rourke, Martin; Young, Andrew; Scott, Christopher; Harrison, Tim; Mullan, Paul; Williams, Rich

    2014-06-01

    This Letter describes the further development and SAR exploration of a novel series of Legumain inhibitors. Based upon a previously identified Legumain inhibitor from our group, we explored the SAR of the carbamate phenyl ring system to probe the P3 pocket of the enzyme. This led to the identification of a sub-nanomolar inhibitor of Legumain. PMID:24775305

  20. Unveiling new chemical scaffolds as Mnk inhibitors.

    PubMed

    Diab, Sarah; Li, Peng; Basnet, Sunita K C; Lu, Jingfeng; Yu, Mingfeng; Albrecht, Hugo; Milne, Robert W; Wang, Shudong

    2016-01-01

    The discovery of small molecules that selectively inhibit Mnks is considered of paramount importance towards deciphering the exact role of these proteins in carcinogenesis and to further validate them as anti-cancer drug targets. However, the dearth of structural information of Mnks is a major hurdle. This study unveils the 7H-pyrrolo[2,3-d]pyrimidine derivatives as potent inhibitors of Mnks. ATP and substrate competition assays showed that this scaffold interacts with the ATP binding site, but not with the substrate site. Screened against a panel of cancer cells, Mnk inhibitors were most potent against MV4-11 acute myeloid leukemia cells. The induction of apoptosis was shown to be mediated by downregulation of Mcl-1. PMID:26910782

  1. Protein synthesis inhibitor from potato tuber

    SciTech Connect

    Romaen, R. )

    1989-04-01

    A protein fraction capable of inhibit in vitro protein synthesis was found in potato tubers in fresh and wounded tissue. Inhibitor activity from fresh tissue decays with wounding. Inhibition activity was detected absorbed to ribsomal fraction and cytosol of potato tuber tissue by a partially reconstituted in vitro system from potato tuber and wheat germ. Adsorbed ribosomal fraction was more suitable of purification. This fraction was washed from ribosomes with 0.3M KCl, concentrated with ammonium sulfate precipitation and purified through sephadex G100 and sephadex G-75 columns chromatography. After 61 fold purification adsorbed protein fraction can inhibit germination of maize, wheat and sesame seeds, as well as {sup 3}H-leucine incorporation into protein by imbibed maize embryos. Inhibition activity was lost by temperature, alkali and protease-K hydrolysis. Preliminar analysis could not show presence of reductor sugars. Physiological role of this inhibitor in relation to rest and active tissue remains to be studied.

  2. Serine protease inhibitors of parasitic helminths.

    PubMed

    Molehin, Adebayo J; Gobert, Geoffrey N; McManus, Donald P

    2012-05-01

    Serine protease inhibitors (serpins) are a superfamily of structurally conserved proteins that inhibit serine proteases and play key physiological roles in numerous biological systems such as blood coagulation, complement activation and inflammation. A number of serpins have now been identified in parasitic helminths with putative involvement in immune regulation and in parasite survival through interference with the host immune response. This review describes the serpins and smapins (small serine protease inhibitors) that have been identified in Ascaris spp., Brugia malayi, Ancylostoma caninum Onchocerca volvulus, Haemonchus contortus, Trichinella spiralis, Trichostrongylus vitrinus, Anisakis simplex, Trichuris suis, Schistosoma spp., Clonorchis sinensis, Paragonimus westermani and Echinococcus spp. and discusses their possible biological functions, including roles in host-parasite interplay and their evolutionary relationships. PMID:22310379

  3. mTOR inhibitors in cancer therapy

    PubMed Central

    Xie, Jianling; Wang, Xuemin; Proud, Christopher G.

    2016-01-01

    The mammalian target of rapamycin, mTOR, plays key roles in cell growth and proliferation, acting at the catalytic subunit of two protein kinase complexes: mTOR complexes 1 and 2 (mTORC1/2). mTORC1 signaling is switched on by several oncogenic signaling pathways and is accordingly hyperactive in the majority of cancers. Inhibiting mTORC1 signaling has therefore attracted great attention as an anti-cancer therapy. However, progress in using inhibitors of mTOR signaling as therapeutic agents in oncology has been limited by a number of factors, including the fact that the classic mTOR inhibitor, rapamycin, inhibits only some of the effects of mTOR; the existence of several feedback loops; and the crucial importance of mTOR in normal physiology.

  4. Development of inhibitors in the ubiquitination cascade.

    PubMed

    Zhang, Wei; Sidhu, Sachdev S

    2014-01-21

    The ubiquitin proteasome system (UPS) is essential in regulating myriad aspects of protein functions. It is therefore a fundamentally important regulatory mechanism that impacts most if not all aspects of cellular processes. Indeed, malfunction of UPS components is implicated in human diseases such as neurodegenerative and immunological disorders and many cancers. The success of proteasome inhibitors in cancer therapy suggests that modulating enzymes in the ubiquitination cascade would be clinically important for therapeutic benefits. In this review, we summarize advances in developing inhibitors of a variety of UPS components. In particular, we highlight recent work done on the protein engineering of ubiquitin as modulators of the UPS, a novel approach that may shed light on innovative drug discovery in the future. PMID:24239534

  5. Naphthyridines as novel BET family bromodomain inhibitors.

    PubMed

    Mirguet, Olivier; Lamotte, Yann; Chung, Chun-Wa; Bamborough, Paul; Delannée, Delphine; Bouillot, Anne; Gellibert, Françoise; Krysa, Gael; Lewis, Antonia; Witherington, Jason; Huet, Pascal; Dudit, Yann; Trottet, Lionel; Nicodeme, Edwige

    2014-03-01

    Bromodomains (BRDs) are small protein domains found in a variety of proteins that recognize and bind to acetylated histone tails. This binding affects chromatin structure and facilitates the localisation of transcriptional complexes to specific genes, thereby regulating epigenetically controlled processes including gene transcription and mRNA elongation. Inhibitors of the bromodomain and extra-terminal (BET) proteins BRD2-4 and T, which prevent bromodomain binding to acetyl-modified histone tails, have shown therapeutic promise in several diseases. We report here the discovery of 1,5-naphthyridine derivatives as potent inhibitors of the BET bromodomain family with good cell activity and oral pharmacokinetic parameters. X-ray crystal structures of naphthyridine isomers have been solved and quantum mechanical calculations have been used to explain the higher affinity of the 1,5-isomer over the others. The best compounds were progressed in a mouse model of inflammation and exhibited dose-dependent anti-inflammatory pharmacology. PMID:24000170

  6. Replacing sulfa drugs with novel DHPS inhibitors

    PubMed Central

    Hammoudeh, Dalia I; Zhao, Ying; White, Stephen W; Lee, Richard E

    2013-01-01

    More research effort needs to be invested in antimicrobial drug development to address the increasing threat of multidrug-resistant organisms. The enzyme DHPS has been a validated drug target for over 70 years as the target for the highly successful sulfa drugs. The use of sulfa drugs has been compromised by the widespread presence of resistant organisms and the adverse side effects associated with their use. Despite the large amount of structural information available for DHPS, few recent publications address the possibility of using this knowledge for novel drug design. This article reviews the relevant papers and patents that report promising new small-molecule inhibitors of DHPS, and discuss these data in light of new insights into the DHPS catalytic mechanism and recently determined crystal structures of DHPS bound to potent small-molecule inhibitors. This new functional understanding confirms that DHPS deserves further consideration as an antimicrobial drug target. PMID:23859210

  7. [Once-weekly DPP-4 inhibitor].

    PubMed

    Harada, Norio; Inagaki, Nobuya

    2015-12-01

    Trelagliptin is the first once-weekly dipeptidyl peptidase-4(DPP-4) inhibitor in the world. Trelagliptin inhibits DPP-4 activity with lower drug concentration compared with other once- (or twice-) daily DPP-4 inhibitors in in vitro study. More than 70 % of DPP-4 activity is inhibited even 1 week after administration of trelagliptin administration in human study. 24-week trelagliptin monotherapy improved HbA1c(-0.33%) and fasting plasma glucose levels in Japanese patients with type 2 diabetes. Trelagliptin did not affect body weight and frequency of hypoglycemic events in this study. 52-week monotherapy and add-on therapy of trelagliptin also improved HbA1c levels without body weight gain and severe hypoglycemia. Therefore, trelagliptin has high efficacy and safety on glucose control in Japanese patients with type 2 diabetes. PMID:26666159

  8. New potential AChE inhibitor candidates.

    PubMed

    de Paula, A A N; Martins, J B L; dos Santos, M L; Nascente, L de C; Romeiro, L A S; Areas, T F M A; Vieira, K S T; Gambôa, N F; Castro, N G; Gargano, R

    2009-09-01

    We have theoretically studied new potential candidates of acetylcholinesterase (AChE) inhibitors designed from cardanol, a non-isoprenoid phenolic lipid of cashew Anacardium occidentale nut-shell liquid. The electronic structure calculations of fifteen molecule derivatives from cardanol were performed using B3LYP level with 6-31G, 6-31G(d), and 6-311+G(2d,p) basis functions. For this study we used the following groups: methyl, acetyl, N,N-dimethylcarbamoyl, N,N-dimethylamine, N,N-diethylamine, piperidine, pyrrolidine, and N,N-methylbenzylamine. Among the proposed compounds we identified that the structures with substitution by N,N-dimethycarbamoyl, N,N-dimethylamine, and pyrrolidine groups were better correlated to rivastigmine, and represent possible AChE inhibitors against Alzheimer disease. PMID:19446931

  9. Inhibitor prevents corrosion, scale in Chinese waterflood

    SciTech Connect

    Yong, W.; Jianhua, W. )

    1994-03-14

    An imidazoline derivative-based series inhibitor has prevented both corrosion and scale formation in produced-water treatment and water-injection equipment in China National Petroleum Co.'s (CNPC) Shengli oil field. Development of the inhibitor started in 1986, and after successful field trials the chemical is now being extensively applied. To increase oil recovery, water injection is widely used in China's onshore oil fields. Oil production in the Shengli oil field, for example, requires injection of about 4 bbl of water/1 bbl of oil produced. The large volumes of produced formation water contain many substances that can cause serious corrosion and scale. Also, the makeup water from other sources, subsurface or surface, complicates water handling. The paper discusses the following: corrosion and scale, oxygen, carbon dioxide, H[sub 2]S and sulfur reducing bacteria, temperature, inhibition, field tests, applications, and economics.

  10. Replacing sulfa drugs with novel DHPS inhibitors.

    PubMed

    Hammoudeh, Dalia I; Zhao, Ying; White, Stephen W; Lee, Richard E

    2013-07-01

    More research effort needs to be invested in antimicrobial drug development to address the increasing threat of multidrug-resistant organisms. The enzyme DHPS has been a validated drug target for over 70 years as the target for the highly successful sulfa drugs. The use of sulfa drugs has been compromised by the widespread presence of resistant organisms and the adverse side effects associated with their use. Despite the large amount of structural information available for DHPS, few recent publications address the possibility of using this knowledge for novel drug design. This article reviews the relevant papers and patents that report promising new small-molecule inhibitors of DHPS, and discuss these data in light of new insights into the DHPS catalytic mechanism and recently determined crystal structures of DHPS bound to potent small-molecule inhibitors. This new functional understanding confirms that DHPS deserves further consideration as an antimicrobial drug target. PMID:23859210

  11. Aurora Kinase Inhibitors: Current Status and Outlook

    PubMed Central

    Bavetsias, Vassilios; Linardopoulos, Spiros

    2015-01-01

    The Aurora kinase family comprises of cell cycle-regulated serine/threonine kinases important for mitosis. Their activity and protein expression are cell cycle regulated, peaking during mitosis to orchestrate important mitotic processes including centrosome maturation, chromosome alignment, chromosome segregation, and cytokinesis. In humans, the Aurora kinase family consists of three members; Aurora-A, Aurora-B, and Aurora-C, which each share a conserved C-terminal catalytic domain but differ in their sub-cellular localization, substrate specificity, and function during mitosis. In addition, Aurora-A and Aurora-B have been found to be overexpressed in a wide variety of human tumors. These observations led to a number of programs among academic and pharmaceutical organizations to discovering small molecule Aurora kinase inhibitors as anti-cancer drugs. This review will summarize the known Aurora kinase inhibitors currently in the clinic, and discuss the current and future directions. PMID:26734566

  12. Drug Delivery Strategies of Chemical CDK Inhibitors.

    PubMed

    Alvira, Daniel; Mondragón, Laura

    2016-01-01

    The pharmacological use of new therapeutics is often limited by a safe and effective drug-delivery system. In this sense, new chemical CDK inhibitors are not an exception. Nanotechnology may be able to solve some of the main problems limiting cancer treatments such as more specific delivery of therapeutics and reduction of toxic secondary effects. It provides new delivery systems able to specifically target cancer cells and release the active molecules in a controlled fashion. Specifically, silica mesoporous supports (SMPS) have emerged as an alternative for more classical drug delivery systems based on polymers. In this chapter, we describe the synthesis of a SMPS containing the CDK inhibitor roscovitine as cargo molecule and the protocols for confirmation of the proper cargo release of the nanoparticles in cell culture employing cell viability, cellular internalization, and cell death induction studies. PMID:26231714

  13. Secreted and transmembrane wnt inhibitors and activators.

    PubMed

    Cruciat, Cristina-Maria; Niehrs, Christof

    2013-03-01

    Signaling by the Wnt family of secreted glycoproteins plays important roles in embryonic development and adult homeostasis. Wnt signaling is modulated by a number of evolutionarily conserved inhibitors and activators. Wnt inhibitors belong to small protein families, including sFRP, Dkk, WIF, Wise/SOST, Cerberus, IGFBP, Shisa, Waif1, APCDD1, and Tiki1. Their common feature is to antagonize Wnt signaling by preventing ligand-receptor interactions or Wnt receptor maturation. Conversely, the Wnt activators, R-spondin and Norrin, promote Wnt signaling by binding to Wnt receptors or releasing a Wnt-inhibitory step. With few exceptions, these antagonists and agonists are not pure Wnt modulators, but also affect additional signaling pathways, such as TGF-β and FGF signaling. Here we discuss their interactions with Wnt ligands and Wnt receptors, their role in developmental processes, as well as their implication in disease. PMID:23085770

  14. mTOR Inhibitors at a Glance

    PubMed Central

    Zheng, Yin; Jiang, Yu

    2016-01-01

    Mechanistic target of rapamycin (mTOR) is a conserved threonine and serine protein kinase that was identified more than two decades ago as the target of immunosuppressive drug rapamycin. Since then considerable amount of information has been learned about the function of this kinase. It is now well-established that mTOR plays a pivotal role in governing cell growth and proliferation, hence making mTOR a therapeutic target for disease conditions caused by deregulated cell proliferation, such as cancer. In the past decade, numerous mTOR inhibitors have been developed and many are currently in clinical trials for cancer treatment. This commentary is to provide a brief summary of these mTOR inhibitors. PMID:27134695

  15. Prospective therapeutic applications of p53 inhibitors

    SciTech Connect

    Gudkov, Andrei V. . E-mail: gudkov@ccf.org; Komarova, Elena A.

    2005-06-10

    p53, in addition to being a key cancer preventive factor, is also a determinant of cancer treatment side effects causing excessive apoptotic death in several normal tissues during cancer therapy. p53 inhibitory strategy has been suggested to protect normal tissues from chemo- and radiotherapy, and to treat other pathologies associated with stress-mediated activation of p53. This strategy was validated by isolation and testing of small molecule p53 inhibitor pifithrin-{alpha} that demonstrated broad tissue protecting capacity. However, in some normal tissues and tumors p53 plays protective role by inducing growth arrest and preventing cells from premature entrance into mitosis and death from mitotic catastrophe. Inhibition of this function of p53 can sensitize tumor cells to chemo- and radiotherapy, thus opening new potential application of p53 inhibitors and justifying the need in pharmacological agents targeting specifically either pro-apoptotic or growth arrest functions of p53.

  16. Neuroserpin, an axonally secreted serine protease inhibitor.

    PubMed Central

    Osterwalder, T; Contartese, J; Stoeckli, E T; Kuhn, T B; Sonderegger, P

    1996-01-01

    We have identified and chromatographically purified an axonally secreted glycoprotein of CNS and PNS neurons. Several peptides derived from it were microsequenced. Based on these sequences, a fragment of the corresponding cDNA was amplified and used as a probe to isolate a full length cDNA from a chicken brain cDNA library. Because the deduced amino acid sequence qualified the protein as a novel member of the serpin family of serine protease inhibitors, we called it neuroserpin. Analysis of the primary structural features further characterized neuroserpin as a heparin-independent, functional inhibitor of a trypsin-like serine protease. In situ hybridization revealed a predominantly neuronal expression during the late stages of neurogenesis and in the adult brain in regions which exhibit synaptic plasticity. Thus, neuroserpin might function as an axonally secreted regulator of the local extracellular proteolysis involved in the reorganization of the synaptic connectivity during development and synapse plasticity in the adult. Images PMID:8670795

  17. Alternative therapies for the management of inhibitors.

    PubMed

    Shima, M; Lillicrap, D; Kruse-Jarres, R

    2016-07-01

    The development of inhibitors to factor VIII (FVIII) or factor IX (FIX) remains a major treatment complication encountered in the treatment of haemophilia. Not all patients with even the same severity and genotype develop inhibitors suggesting an underlying mechanism of tolerance against FVIII- or FIX-related immunity. One mechanism may be central tolerance observed in patients in whom the FVIII mutation enables some production of the protein. The other is a peripheral tolerance mechanism which may be evident in patients with null mutation. Recently, recombinant porcine FVIII (rpFVIII, Obixur, OBI-1, BAX801) has been developed for the haemostatic treatment of both congenital haemophilia with inhibitor (CHAWI) and acquired haemophilia A (AHA). In 28 subjects with AHA with life-/limb-threatening bleeding, rpFVIII reduced or stopped bleeding in all patients within 24 h. The cross-reactivity of anti-human FVIII antibodies to rpFVIII remains around 30-50%. Recently, new therapeutics based on the quite novel concepts have been developed and clinical studies are ongoing. These are humanized asymmetric antibody mimicking FVIIIa function by maintaining a suitable interaction between FIXa and FX (Emicizumab, ACE910), and small interfering RNAs (siRNA, ALN-AT3) suppress liver production of AT through post-transcriptional gene silencing and a humanized anti-TFPI monoclonal antibody (Concizumab). Their main advantages are longer half-life, subcutaneous applicability and efficacy irrespective of the presence of inhibitors which will make it easier to initiate more effective treatment especially early childhood. PMID:27405674

  18. Trial Watch: Proteasomal inhibitors for anticancer therapy

    PubMed Central

    Obrist, Florine; Manic, Gwenola; Kroemer, Guido; Vitale, Ilio; Galluzzi, Lorenzo

    2015-01-01

    The so-called “ubiquitin-proteasome system” (UPS) is a multicomponent molecular apparatus that catalyzes the covalent attachment of several copies of the small protein ubiquitin to other proteins that are generally (but not always) destined to proteasomal degradation. This enzymatic cascade is crucial for the maintenance of intracellular protein homeostasis (both in physiological conditions and in the course of adaptive stress responses), and regulates a wide array of signaling pathways. In line with this notion, defects in the UPS have been associated with aging as well as with several pathological conditions including cardiac, neurodegenerative, and neoplastic disorders. As transformed cells often experience a constant state of stress (as a result of the hyperactivation of oncogenic signaling pathways and/or adverse microenvironmental conditions), their survival and proliferation are highly dependent on the integrity of the UPS. This rationale has driven an intense wave of preclinical and clinical investigation culminating in 2003 with the approval of the proteasomal inhibitor bortezomib by the US Food and Drug Administration for use in multiple myeloma patients. Another proteasomal inhibitor, carfilzomib, is now licensed by international regulatory agencies for use in multiple myeloma patients, and the approved indications for bortezomib have been extended to mantle cell lymphoma. This said, the clinical activity of bortezomib and carfilzomib is often limited by off-target effects, innate/acquired resistance, and the absence of validated predictive biomarkers. Moreover, the antineoplastic activity of proteasome inhibitors against solid tumors is poor. In this Trial Watch we discuss the contribution of the UPS to oncogenesis and tumor progression and summarize the design and/or results of recent clinical studies evaluating the therapeutic profile of proteasome inhibitors in cancer patients. PMID:27308423

  19. Aromatase inhibitors and anti-synthetase syndrome.

    PubMed

    Mascella, Fabio; Gianni, Lorenzo; Affatato, Alessandra; Fantini, Manuela

    2016-09-01

    Adjuvant therapy in postmenopausal women with endocrine-responsive breast cancer (BC) is actually centered on the use of anti-aromatase inhibitors (AI). Several reports, however, are emerging in literature associating the use of this drugs to rheumatic disorders. This case report describes the first case of anti-synthetase syndrome diagnosis after treatment with anti-estrogen agents in a patient with pre-existing rheumatoid arthritis. PMID:27225465

  20. Serendipity in discovery of proteasome inhibitors.

    PubMed

    Dunn, Derek; Iqbal, Mohamed; Husten, Jean; Ator, Mark A; Chatterjee, Sankar

    2012-05-15

    Among its various catalytic activities, the 'chymotrypsin-like' activity of the proteasome, a large multicatalytic proteinase complex has emerged as the focus of drug discovery efforts in cancer therapy. Herein, a series of first generation (2S, 3R)-2-amino-3-hydroxybutyric acid derived proteasome inhibitors that were discovered serendipitously en route to original goal of generating a series of sterically constrained oxazoline derivatives has been reported. PMID:22503349

  1. Inhibitors of the AAA+ Chaperone p97

    PubMed Central

    Chapman, Eli; Maksim, Nick; de la Cruz, Fabian; La Clair, James J.

    2015-01-01

    It is remarkable that a pathway as ubiquitous as protein quality control can be targeted to treat cancer. Bortezomib, an inhibitor of the proteasome, was first approved by the US Food and Drug Administration (FDA) more than 10 years ago to treat refractory myeloma and later extended to lymphoma. Its use has increased the survival rate of myeloma patients by as much as three years. This success was followed with the recent accelerated approval of the natural product derived proteasome inhibitor carfilzomib (Kyprolis®), which is used to treat patients with bortezomib-resistant multiple myeloma. The success of these two drugs has validated protein quality control as a viable target to fight select cancers, but begs the question why are proteasome inhibitors limited to lymphoma and myeloma? More recently, these limitations have encouraged the search for additional targets within the protein quality control system that might offer heightened cancer cell specificity, enhanced clinical utility, a lower rate of resistance, reduced toxicity, and mitigated side effects. One promising target is p97, an ATPase associated with various cellular activities (AAA+) chaperone. p97 figures prominently in protein quality control as well as serving a variety of other cellular functions associated with cancer. More than a decade ago, it was determined that up-regulation of p97 in many forms of cancer correlates with a poor clinical outcome. Since these initial discoveries, a mechanistic explanation for this observation has been partially illuminated, but details are lacking. Understandably, given this clinical correlation, myriad roles within the cell, and its importance in protein quality control, p97 has emerged as a potential therapeutic target. This review provides an overview of efforts towards the discovery of small molecule inhibitors of p97, offering a synopsis of efforts that parallel the excellent reviews that currently exist on p97 structure, function, and physiology. PMID

  2. Trial Watch: Proteasomal inhibitors for anticancer therapy.

    PubMed

    Obrist, Florine; Manic, Gwenola; Kroemer, Guido; Vitale, Ilio; Galluzzi, Lorenzo

    2015-01-01

    The so-called "ubiquitin-proteasome system" (UPS) is a multicomponent molecular apparatus that catalyzes the covalent attachment of several copies of the small protein ubiquitin to other proteins that are generally (but not always) destined to proteasomal degradation. This enzymatic cascade is crucial for the maintenance of intracellular protein homeostasis (both in physiological conditions and in the course of adaptive stress responses), and regulates a wide array of signaling pathways. In line with this notion, defects in the UPS have been associated with aging as well as with several pathological conditions including cardiac, neurodegenerative, and neoplastic disorders. As transformed cells often experience a constant state of stress (as a result of the hyperactivation of oncogenic signaling pathways and/or adverse microenvironmental conditions), their survival and proliferation are highly dependent on the integrity of the UPS. This rationale has driven an intense wave of preclinical and clinical investigation culminating in 2003 with the approval of the proteasomal inhibitor bortezomib by the US Food and Drug Administration for use in multiple myeloma patients. Another proteasomal inhibitor, carfilzomib, is now licensed by international regulatory agencies for use in multiple myeloma patients, and the approved indications for bortezomib have been extended to mantle cell lymphoma. This said, the clinical activity of bortezomib and carfilzomib is often limited by off-target effects, innate/acquired resistance, and the absence of validated predictive biomarkers. Moreover, the antineoplastic activity of proteasome inhibitors against solid tumors is poor. In this Trial Watch we discuss the contribution of the UPS to oncogenesis and tumor progression and summarize the design and/or results of recent clinical studies evaluating the therapeutic profile of proteasome inhibitors in cancer patients. PMID:27308423

  3. Corrosion Inhibitors as Penetrant Dyes for Radiography

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Hall, Phillip B.

    2003-01-01

    Liquid/vapor-phase corrosion inhibitors (LVCIs) have been found to be additionally useful as penetrant dyes for neutron radiography (and perhaps also x-radiography). Enhancement of radiographic contrasts by use of LVCIs can reveal cracks, corrosion, and other defects that may be undetectable by ultrasonic inspection, that are hidden from direct optical inspection, and/or that are difficult or impossible to detect in radiographs made without dyes.

  4. Rust Inhibitor And Fungicide For Cooling Systems

    NASA Technical Reports Server (NTRS)

    Adams, James F.; Greer, D. Clay

    1988-01-01

    Mixture of benzotriazole, benzoic acid, and fungicide prevents growth of rust and fungus. Water-based cooling mixture made from readily available materials prevents formation of metallic oxides and growth of fungi in metallic pipes. Coolant remains clear and does not develop thick sludge tending to collect in low points in cooling systems with many commercial rust inhibitors. Coolant compatible with iron, copper, aluminum, and stainless steel. Cannot be used with cadmium or cadmium-plated pipes.

  5. Corrosion protection with eco-friendly inhibitors

    NASA Astrophysics Data System (ADS)

    Shahid, Muhammad

    2011-12-01

    Corrosion occurs as a result of the interaction of a metal with its environment. The extent of corrosion depends on the type of metal, the existing conditions in the environment and the type of aggressive ions present in the medium. For example, CO3‑2 and NO‑3 produce an insoluble deposit on the surface of iron, resulting in the isolation of metal and consequent decrease of corrosion. On the other hand, halide ions are adsorbed selectively on the metal surface and prevent formation of the oxide phase on the metal surface, resulting in continuous corrosion. Iron, aluminum and their alloys are widely used, both domestically and industrially. Linear alkylbenzene and linear alkylbenzene sulfonate are commonly used as detergents. They have also been found together in waste water. It is claimed that these chemicals act as inhibitors for stainless steel and aluminum. Release of toxic gases as a result of corrosion in pipelines may lead in certain cases to air pollution and possible health hazards. Therefore, there are two ways to look at the relationship between corrosion and pollution: (i) corrosion of metals and alloys due to environmental pollution and (ii) environmental pollution as a result of corrosion protection. This paper encompasses the two scenarios and possible remedies for various cases, using 'green' inhibitors obtained either from plant extracts or from pharmaceutical compounds. In the present study, the effect of piperacillin sodium as a corrosion inhibitor for mild steel was investigated using a weight-loss method as well as a three-electrode dc electrochemical technique. It was found that the corrosion rate decreased as the concentration of the inhibitor increased up to 9×10‑4 M 93% efficiency was exhibited at this concentration.

  6. Fluorinated dissolution inhibitors for 157-nm lithography

    NASA Astrophysics Data System (ADS)

    Hamad, Alyssandrea H.; Bae, Young C.; Liu, Xiang-Qian; Ober, Christopher K.; Houlihan, Francis M.; Dabbagh, Gary; Novembre, Anthony E.

    2002-07-01

    Fluorinated dissolution inhibitors (DIs) for 157 nm lithography were designed and synthesized as part of an ongoing study on the structure/property relationships of photoresist additives. The problem of volatilization of small DI candidates was observed from matrices such as poly(methyl methacrylate) (PMMA) and poly(hexafluorohydroxy-isopropyl styrene) (PHFHIPS) during post-apply bake cycles using Fourier Transform Infrared Spectroscopy (FT-IR). To avoid this problem, low volatility fluorinated inhibitors were designed and synthesized. Three fluorinated DIs, perfluorosuberic acid bis-(2,2,2,-trifluoro-1-phenyl-1-trifluoromethyl-ethyl) ester (PFSE1), perfluorosuberic acid bis-[1-(4-trifluoromethyl-phenyl)-ethyl] ester (PFSE2) and a fluorinated phenylmethanediol diester (FPMD1), largely remained in a PHFHIPS film during the post-apply bake. The dissolution behavior of the two fluorinated diesters was studied and found to slow down the dissolution rate of PHFHIPS with inhibition factors of 1.9 and 1.6, respectively. The absorbance of PHFHIPS films containing 10 wt% of the diester inhibitors is 3.6 AU/micron compared with an absorbance of 3.3 AU/micron for the polymer itself. The absorbance of 10% FPMD1 in PHFHIPS was measured as 3.5 AU/micron compared with an absorbance of 3.4 AU/micron for the polymer itself. Thus, the non-volatility and transparency of the fluorinated inhibitors at 157 nm as well as their ability to reduce the development rate of fluorinated polymers make them suitable for use in a 157 nm resist system.

  7. Effect of variables on downhole corrosion inhibitor application

    SciTech Connect

    Dougherty, J.A.

    1996-08-01

    One inhibitor was studied in detail to determine the effect of solvent, temperature, concentration and contact time on inhibitor application. The laboratory corrosion tests used the rotating cylinder electrode and linear polarization to measure the corrosion rate. The corrosion rate was also verified by iron loss measurements. Inhibitor was extracted from the electrode surface and the quantity determined by gas liquid chromatography. The inhibitor was also detected on the surface of the electrode by Fourier Transform Infrared spectroscopy. Corrosion rate data monitored in the field and inhibitor residue on field coupons confirm the laboratory test data.

  8. TGF-beta inhibitors for the treatment of cancer.

    PubMed

    Lahn, Michael; Kloeker, Susanne; Berry, Brandi S

    2005-06-01

    Advances in understanding the role of transforming growth factor (TGF)-beta in tumorigenesis have led to the development of TGF-beta inhibitors for cancer treatment. Three platforms of TGF-beta inhibitors have evolved: antisense oligonucleotides, monoclonal antibodies and small molecules. In this review, the current stage of development of each known TGF-beta inhibitor will be discussed. As part of the risk/benefit assessment of TGF-beta inhibitors, the known effects of TGF-beta deficiency in mice, non-clinical toxicology studies with TGF-beta inhibitors in rats, and the clinical studies with monoclonal antibodies against TGF-beta will be summarised. PMID:16004592

  9. Structure-Based Search for New Inhibitors of Cholinesterases

    PubMed Central

    Bajda, Marek; Więckowska, Anna; Hebda, Michalina; Guzior, Natalia; Sotriffer, Christoph A.; Malawska, Barbara

    2013-01-01

    Cholinesterases are important biological targets responsible for regulation of cholinergic transmission, and their inhibitors are used for the treatment of Alzheimer’s disease. To design new cholinesterase inhibitors, of different structure-based design strategies was followed, including the modification of compounds from a previously developed library and a fragment-based design approach. This led to the selection of heterodimeric structures as potential inhibitors. Synthesis and biological evaluation of selected candidates confirmed that the designed compounds were acetylcholinesterase inhibitors with IC50 values in the mid-nanomolar to low micromolar range, and some of them were also butyrylcholinesterase inhibitors. PMID:23478436

  10. Optogenetic Inhibitor of the Transcription Factor CREB.

    PubMed

    Ali, Ahmed M; Reis, Jakeb M; Xia, Yan; Rashid, Asim J; Mercaldo, Valentina; Walters, Brandon J; Brechun, Katherine E; Borisenko, Vitali; Josselyn, Sheena A; Karanicolas, John; Woolley, G Andrew

    2015-11-19

    Current approaches for optogenetic control of transcription do not mimic the activity of endogenous transcription factors, which act at numerous sites in the genome in a complex interplay with other factors. Optogenetic control of dominant negative versions of endogenous transcription factors provides a mechanism for mimicking the natural regulation of gene expression. Here we describe opto-DN-CREB, a blue-light-controlled inhibitor of the transcription factor CREB created by fusing the dominant negative inhibitor A-CREB to photoactive yellow protein (PYP). A light-driven conformational change in PYP prevents coiled-coil formation between A-CREB and CREB, thereby activating CREB. Optogenetic control of CREB function was characterized in vitro, in HEK293T cells, and in neurons where blue light enabled control of expression of the CREB targets NR4A2 and c-Fos. Dominant negative inhibitors exist for numerous transcription factors; linking these to optogenetic domains offers a general approach for spatiotemporal control of native transcriptional events. PMID:26590638

  11. Histone deacetylase inhibitors as cancer therapeutics.

    PubMed

    Clawson, Gary A

    2016-08-01

    Cancer cells contain significant alterations in their epigenomic landscape, which several enzyme families reversibly contribute to. One class of epigenetic modifying enzymes is that of histone deacetylases (HDAC), which are receiving considerable scrutiny clinically as a therapeutic target in many cancers. The underlying rationale is that inhibiting HDACs will reverse dysregulated target gene expression by modulating functional histone (or other) acetylation marks. This perspective will discuss a recent paper by Markozashvili and co-workers which appeared in Gene, which indicates that the mechanisms by which HDAC inhibitors (HDACis) alter the epigenetic landscape include widespread alternative effects beyond simply controlling regional epigenetic marks. HDACs are involved in many processes/diseases, and it is not surprising that HDACis have considerable off-target effects, and thus a major effort is being directed toward identification of inhibitors which are selective for HDAC isoforms often uniquely implicated in various cancers. This Perspective will also discuss some representative work with inhibitors targeting individual HDAC classes or isoforms. At present, it is not really clear that isoform-specific HDACis will avoid non-selective effects on other unrecognized activities of HDACs. PMID:27568481

  12. CYP17 inhibitors for prostate cancer therapy.

    PubMed

    Vasaitis, Tadas S; Bruno, Robert D; Njar, Vincent C O

    2011-05-01

    Prostate cancer (PC) is now the second most prevalent cause of death in men in the USA and Europe. At present, the major treatment options include surgical or medical castration. These strategies cause ablation of the production of testosterone (T), dihydrotestosterone (DHT) and related androgens by the testes. However, because these procedures do not affect adrenal, prostate and other tissues' androgen production, they are often combined with androgen receptor antagonists to block their action. Indeed, recent studies have unequivocally established that in castration-resistant prostate cancer (CRPC) many androgen-regulated genes become re-expressed and tissue androgen levels increase despite low serum levels. Clearly, inhibition of the key enzyme which catalyzes the biosynthesis of androgens from pregnane precursors, 17α-hydroxy/17,20-lyase (hereafter referred to as CYP17) could prevent androgen production from all sources. Thus, total ablation of androgen production by potent CYP17 inhibitors may provide effective treatment of prostate cancer patients. This review highlights the role of androgen biosynthesis in the progression of prostate cancer and the impact of CYP17 inhibitors, such as ketoconazole, abiraterone acetate, VN/124-1 (TOK-001) and TAK-700 in the clinic and in clinical development. Article from the special issue on Targeted Inhibitors. PMID:21092758

  13. Immune checkpoint inhibitors: therapeutic advances in melanoma

    PubMed Central

    Márquez-Rodas, Ivan; Cerezuela, Pablo; Soria, Ainara; Berrocal, Alfonso; Riso, Aldo; Martín-Algarra, Salvador

    2015-01-01

    In recent years, new strategies for treating melanoma have been introduced, improving the outlook for this challenging disease. One of the most important advances has been the development of immunotherapy. The better understanding of the role of the immunological system in tumor control has paved the way for strategies to enhance the immune response against cancer cells. Monoclonal antibodies (mAbs) against the immune checkpoints cytotoxic T-lymphocyte antigen-4 (CTLA-4) and programmed cell death protein 1 (PD-1) and its ligand (PD-L1) have demonstrated high activity in melanoma and other tumors. Ipilimumab, an anti CTLA-4 antibody, was the first drug of this class that was approved. Although the response rate with ipilimumab is low (less than 20% of patients have objective responses), 20% of patients have long survival, with similar results in the first and second line settings. Nivolumab and pembrolizumab, both anti PD-1 inhibitors, have been approved for the treatment of melanoma, with response rates of 40% and a demonstrated survival advantage in phase III trials. This has marked a new era in the treatment of metastatic melanoma and much research is now ongoing with other drugs targeting checkpoint inhibitors. In addition, the agonist of activating molecules on T cells and their combinations are being investigated. Herein we review the clinical development of checkpoint inhibitors and their approval for treatment of metastatic melanoma. PMID:26605313

  14. Histone deacetylase inhibitors as cancer therapeutics

    PubMed Central

    2016-01-01

    Cancer cells contain significant alterations in their epigenomic landscape, which several enzyme families reversibly contribute to. One class of epigenetic modifying enzymes is that of histone deacetylases (HDAC), which are receiving considerable scrutiny clinically as a therapeutic target in many cancers. The underlying rationale is that inhibiting HDACs will reverse dysregulated target gene expression by modulating functional histone (or other) acetylation marks. This perspective will discuss a recent paper by Markozashvili and co-workers which appeared in Gene, which indicates that the mechanisms by which HDAC inhibitors (HDACis) alter the epigenetic landscape include widespread alternative effects beyond simply controlling regional epigenetic marks. HDACs are involved in many processes/diseases, and it is not surprising that HDACis have considerable off-target effects, and thus a major effort is being directed toward identification of inhibitors which are selective for HDAC isoforms often uniquely implicated in various cancers. This Perspective will also discuss some representative work with inhibitors targeting individual HDAC classes or isoforms. At present, it is not really clear that isoform-specific HDACis will avoid non-selective effects on other unrecognized activities of HDACs. PMID:27568481

  15. The hunt for HIV-1 integrase inhibitors.

    PubMed

    Lataillade, Max; Kozal, Michael J

    2006-07-01

    Currently, there are three distinct mechanistic classes of antiretrovirals: inhibitors of the HIV- 1 reverse transcriptase and protease enzymes and inhibitors of HIV entry, including receptor and coreceptor binding and cell fusion. A new drug class that inhibits the HIV-1 integrase enzyme (IN) is in development and may soon be available in the clinic. IN is an attractive drug target because it is essential for a stable and productive HIV-1 infection and there is no mammalian homologue of IN. Inhibitors of integrase enzyme (INI) block the integration of viral double-stranded DNA into the host cell's chromosomal DNA. HIV-1 integration has many potential steps that can be inhibited and several new compounds that target specific integration steps have been identified by drug developers. Recently, two INIs, GS-9137 and MK-0518, demonstrated promising early clinical trial results and have been advanced into later stage trials. In this review, we describe how IN facilitates HIV-1 integration, the needed enzyme cofactors, and the resultant byproducts created during integration. Furthermore, we review the different INIs under development, their mechanism of actions, site of IN inhibition, potency, resistance patterns, and discuss the early clinical trial results. PMID:16839248

  16. Dual Inhibitors Against Topoisomerases and Histone Deacetylases

    PubMed Central

    Seo, Young Ho

    2015-01-01

    Topoisomerases and histone deacetylases (HDACs) are considered as important therapeutic targets for a wide range of cancers, due to their association with the initiation, proliferation and survival of cancer cells. Topoisomerases are involved in the cleavage and religation processes of DNA, while HDACs regulate a dynamic epigenetic modification of the lysine amino acid on various proteins. Extensive studies have been undertaken to discover small molecule inhibitor of each protein and thereby, several drugs have been transpired from this effort and successfully approved for clinical use. However, the inherent heterogeneity and multiple genetic abnormalities of cancers challenge the clinical application of these single targeted drugs. In order to overcome the limitations of a single target approach, a novel approach, simultaneously targeting topoisomerases and HDACs with a single molecule has been recently employed and attracted much attention of medicinal chemists in drug discovery. This review highlights the current studies on the discovery of dual inhibitors against topoisomerases and HDACs, provides their pharmacological aspects and advantages, and discusses the challenges and promise of the dual inhibitors. PMID:26151040

  17. Selective Water-Soluble Gelatinase Inhibitor Prodrugs

    PubMed Central

    Gooyit, Major; Lee, Mijoon; Schroeder, Valerie A.; Ikejiri, Masahiro; Suckow, Mark A.; Mobashery, Shahriar; Chang, Mayland

    2011-01-01

    SB-3CT (1), a selective and potent thiirane-based gelatinase inhibitor, is effective in animal models of cancer metastasis and stroke; however, it is limited by poor aqueous solubility and extensive metabolism. We addressed these issues by blocking the primary site of metabolism and capitalizing on a prodrug strategy to achieve >5000-fold increased solubility. The amide prodrugs were quantitatively hydrolyzed in human blood to a potent gelatinase inhibitor, ND-322 (3). The arginyl amide prodrug (ND-478, 5d) was metabolically stable in mouse, rat, and human liver microsomes. Both 5d and 3 were non-mutagenic in the Ames II mutagenicity assay. The prodrug 5d showed moderate clearance of 0.0582 L/min/kg, remained mostly in the extracellular fluid compartment (Vd = 0.0978 L/kg), and had a terminal half-life of >4 h. The prodrug 5d had superior pharmacokinetic properties than 3, making the thiirane class of selective gelatinase inhibitors suitable for intravenous administration in treatment of acute gelatinase-dependent diseases. PMID:21866961

  18. Cinnoline derivatives as human neutrophil elastase inhibitors.

    PubMed

    Giovannoni, Maria Paola; Schepetkin, Igor A; Crocetti, Letizia; Ciciani, Giovanna; Cilibrizzi, Agostino; Guerrini, Gabriella; Khlebnikov, Andrei I; Quinn, Mark T; Vergelli, Claudia

    2016-08-01

    Compounds that can effectively inhibit the proteolytic activity of human neutrophil elastase (HNE) represent promising therapeutics for treatment of inflammatory diseases. We present here the synthesis, structure-activity relationship analysis, and biological evaluation of a new series of HNE inhibitors with a cinnoline scaffold. These compounds exhibited HNE inhibitory activity but had lower potency compared to N-benzoylindazoles previously reported by us. On the other hand, they exhibited increased stability in aqueous solution. The most potent compound, 18a, had a good balance between HNE inhibitory activity (IC50 value = 56 nM) and chemical stability (t1/2 = 114 min). Analysis of reaction kinetics revealed that these cinnoline derivatives were reversible competitive inhibitors of HNE. Furthermore, molecular docking studies of the active products into the HNE binding site revealed two types of HNE inhibitors: molecules with cinnolin-4(1H)-one scaffold, which were attacked by the HNE Ser195 hydroxyl group at the amido moiety, and cinnoline derivatives containing an ester function at C-4, which is the point of attack of Ser195. PMID:26194018

  19. Janus kinase inhibitors for rheumatoid arthritis.

    PubMed

    Yamaoka, Kunihiro

    2016-06-01

    Treatment of autoimmune diseases, such as rheumatoid arthritis (RA), has advanced substantially over the past decade with the development of biologics targeting inflammatory cytokines. Recent progress in treating RA has been achieved with janus kinase (JAK) inhibitors (Jakinibs), an orally available disease-modifying anti-rheumatic drug targeting the intracellular kinase JAK and with similar efficacy to biologics. The first Jakinib approved for RA was tofacitinib, which exerted superiority to methotrexate and non-inferiority to tumor necrosis factor (TNF) inhibitors. In recent years, the Jakinib baricitinib has demonstrated superiority to both methotrexate and a TNF inhibitor, adalimumab. Given these promising findings, Jakinibs are expected to represent the next generation compounds for treating RA, and a number of Jakinibs are currently in clinical trials. Jakinibs can differ substantially in their selectivity against JAKs; tofacitinib and baricitinib target multiple JAKs, whereas the most recently developed Jakinibs target only a single JAK. The influence of Jakinib selectivity on efficacy and side effects is of great interest, requiring further careful observation. PMID:26994322

  20. Immune Checkpoint Inhibitors in Older Adults.

    PubMed

    Elias, Rawad; Morales, Joshua; Rehman, Yasser; Khurshid, Humera

    2016-08-01

    Cancer is primarily a disease of older adults. The treatment of advanced stage tumors usually involves the use of systemic agents that may be associated with significant risk of toxicity, especially in older patients. Immune checkpoint inhibitors are newcomers to the oncology world with improved efficacy and better safety profiles when compared to traditional cytotoxic drugs. This makes them an attractive treatment option. While there are no elderly specific trials, this review attempts to look at the current available data from a geriatric oncology perspective. We reviewed data from phase III studies that led to newly approved indications of checkpoint inhibitors in non-small cell lung cancer, melanoma, and renal cell cancer. Data were reviewed with respect to response, survival, and toxicity according to three groups: <65 years, 65-75 years, and >75 years. Current literature does not allow one to draw definitive conclusions regarding the role of immune checkpoint inhibitors in older adults. However, they may offer a potentially less toxic but equally efficacious treatment option for the senior adult oncology patient. PMID:27287329

  1. Functional Analysis of Hsp70 Inhibitors

    PubMed Central

    Dahmen, Heike; Wegener, Ansgar; Sirrenberg, Christian; Musil, Djordje; Bomke, Joerg; Eggenweiler, Hans-Michael; Mayer, Matthias P.; Bukau, Bernd

    2013-01-01

    The molecular chaperones of the Hsp70 family have been recognized as targets for anti-cancer therapy. Since several paralogs of Hsp70 proteins exist in cytosol, endoplasmic reticulum and mitochondria, we investigated which isoform needs to be down-regulated for reducing viability of cancer cells. For two recently identified small molecule inhibitors, VER-155008 and 2-phenylethynesulfonamide (PES), which are proposed to target different sites in Hsp70s, we analyzed the molecular mode of action in vitro. We found that for significant reduction of viability of cancer cells simultaneous knockdown of heat-inducible Hsp70 (HSPA1) and constitutive Hsc70 (HSPA8) is necessary. The compound VER-155008, which binds to the nucleotide binding site of Hsp70, arrests the nucleotide binding domain (NBD) in a half-open conformation and thereby acts as ATP-competitive inhibitor that prevents allosteric control between NBD and substrate binding domain (SBD). Compound PES interacts with the SBD of Hsp70 in an unspecific, detergent-like fashion, under the conditions tested. None of the two inhibitors investigated was isoform-specific. PMID:24265689

  2. Sulfated chitooligosaccharides as prolyl endopeptidase inhibitor.

    PubMed

    Je, Jae-Young; Kim, Eun-Kyung; Ahn, Chang-Bum; Moon, Sang-Ho; Jeon, Byong-Tae; Kim, Bokyung; Park, Tae-Kyu; Park, Pyo-Jam

    2007-12-01

    Prolyl endopeptidase (PEP, EC 3.4.21.26) is a proline-specific endopeptidase with a serine-type mechanism, which digests small peptide-like hormones, neuroactive peptides, and various cellular factors. PEP has been involved in neurodegenerative disorders, therefore, the discovery of PEP inhibitors can revert memory loss caused by amnesic compounds. In this study, we prepared hetero-chitooligosaccharides (COSs) with different molecular sizes using ultrafiltration (UF) membrane reactor system from hetero-chitosan with different degrees of deacetylation (DD; 90%, 75% and 50% deacetylation), and synthesized sulfated COSs (SCOSs). PEP inhibitory activities of SCOSs were evaluated and the results showed that 50% deacetylated SCOSs (50-SCOSs) exhibited higher inhibitory activities than those of 90% and 75% deacetylated SCOSs (90-SCOSs and 75-SCOSs). Among the 50-SCOSs (50-SCOS I, 5000-10,000Da; 50-SCOS II, 1000-5000Da; 50-SCOS III, below 1000Da), 50-SCOS II possessed the highest inhibitory activity and IC(50) value was 0.38mg/ml. Kinetics studies with 50-SCOS II indicated a competitive enzyme inhibition with a K(i) value of 0.78mg/ml. It was concluded that the 50-SCOS II may be useful for PEP inhibitor and for developing a new type PEP inhibitor from carbohydrate based materials. PMID:17714777

  3. Effect of treatment method on corrosion inhibitor performance

    SciTech Connect

    Dougherty, J.A.

    1997-12-01

    Two types of corrosion inhibitors are studied in laboratory tests simulating batch and continuous treatment methods. Type 1 is an inhibitor which is adsorbed on the corrosion product layer and forms an inhibitor film. Type 2 reacts with the corrosion product layer to form a protective film. With both inhibitors, the protection offered by continuous treatment at 100 to 1,000 ppm inhibitor compared favorably with batch treatment using neat or 10% solutions of inhibitor. The results show batch treatment of gas phase and liquid phase coupons with a 50% solution of Type 1 inhibitor gives optimum protection. The treatment gave 91% protection on the liquid phase coupons and only 70% protection on the gas phase coupons, indicating the gas phase coupons are more difficult to inhibit. Batch treatment with neat Type 2 inhibitor gave better protection than treatment with 10% solutions of the inhibitor in methanol, crude oil or resid oil. The Type 2 inhibitor at 100 ppm in a continuous application gave as much protection as batch treatment with neat or 10% solutions of the inhibitor in solvents.

  4. Solution structures of stromelysin complexed to thiadiazole inhibitors.

    PubMed Central

    Stockman, B. J.; Waldon, D. J.; Gates, J. A.; Scahill, T. A.; Kloosterman, D. A.; Mizsak, S. A.; Jacobsen, E. J.; Belonga, K. L.; Mitchell, M. A.; Mao, B.; Petke, J. D.; Goodman, L.; Powers, E. A.; Ledbetter, S. R.; Kaytes, P. S.; Vogeli, G.; Marshall, V. P.; Petzold, G. L.; Poorman, R. A.

    1998-01-01

    Unregulated or overexpressed matrix metalloproteinases (MMPs), including stromelysin, collagenase, and gelatinase. have been implicated in several pathological conditions including arthritis and cancer. Small-molecule MMP inhibitors may have therapeutic value in the treatment of these diseases. In this regard, the solution structures of two stromelysin/ inhibitor complexes have been investigated using 1H, 13C, and 15N NMR spectroscopy. Both-inhibitors are members of a novel class of matrix metalloproteinase inhibitor that contain a thiadiazole group and that interact with stromelysin in a manner distinct from other classes of inhibitors. The inhibitors coordinate the catalytic zinc atom through their exocyclic sulfur atom, with the remainder of the ligand extending into the S1-S3 side of the active site. The binding of inhibitor containing a protonated or fluorinated aromatic ring was investigated using 1H and 19F NMR spectroscopy. The fluorinated ring was found to have a reduced ring-flip rate compared to the protonated version. A strong, coplanar interaction between the fluorinated ring of the inhibitor and the aromatic ring of Tyr155 is proposed to account for the reduced ring-flip rate and for the increase in binding affinity observed for the fluorinated inhibitor compared to the protonated inhibitor. Binding interactions observed for the thiadiazole class of ligands have implications for the design of matrix metalloproteinase inhibitors. PMID:9827994

  5. Molecular mechanism of respiratory syncytial virus fusion inhibitors

    PubMed Central

    Battles, Michael B; Langedijk, Johannes P; Furmanova-Hollenstein, Polina; Chaiwatpongsakorn, Supranee; Costello, Heather M; Kwanten, Leen; Vranckx, Luc; Vink, Paul; Jaensch, Steffen; Jonckers, Tim H M; Koul, Anil; Arnoult, Eric; Peeples, Mark E; Roymans, Dirk; McLellan, Jason S

    2016-01-01

    Respiratory syncytial virus (RSV) is a leading cause of pneumonia and bronchiolitis in young children and the elderly. Therapeutic small molecules have been developed that bind the RSV F glycoprotein and inhibit membrane fusion, yet their binding sites and molecular mechanisms of action remain largely unknown. Here we show that these inhibitors bind to a three-fold-symmetric pocket within the central cavity of the metastable prefusion conformation of RSV F. Inhibitor binding stabilizes this conformation by tethering two regions that must undergo a structural rearrangement to facilitate membrane fusion. Inhibitor-escape mutations occur in residues that directly contact the inhibitors or are involved in the conformational rearrangements required to accommodate inhibitor binding. Resistant viruses do not propagate as well as wild-type RSV in vitro, indicating a fitness cost for inhibitor escape. Collectively, these findings provide new insight into class I viral fusion proteins and should facilitate development of optimal RSV fusion inhibitors. PMID:26641933

  6. Molecular mechanism of respiratory syncytial virus fusion inhibitors.

    PubMed

    Battles, Michael B; Langedijk, Johannes P; Furmanova-Hollenstein, Polina; Chaiwatpongsakorn, Supranee; Costello, Heather M; Kwanten, Leen; Vranckx, Luc; Vink, Paul; Jaensch, Steffen; Jonckers, Tim H M; Koul, Anil; Arnoult, Eric; Peeples, Mark E; Roymans, Dirk; McLellan, Jason S

    2016-02-01

    Respiratory syncytial virus (RSV) is a leading cause of pneumonia and bronchiolitis in young children and the elderly. Therapeutic small molecules have been developed that bind the RSV F glycoprotein and inhibit membrane fusion, yet their binding sites and molecular mechanisms of action remain largely unknown. Here we show that these inhibitors bind to a three-fold-symmetric pocket within the central cavity of the metastable prefusion conformation of RSV F. Inhibitor binding stabilizes this conformation by tethering two regions that must undergo a structural rearrangement to facilitate membrane fusion. Inhibitor-escape mutations occur in residues that directly contact the inhibitors or are involved in the conformational rearrangements required to accommodate inhibitor binding. Resistant viruses do not propagate as well as wild-type RSV in vitro, indicating a fitness cost for inhibitor escape. Collectively, these findings provide new insight into class I viral fusion proteins and should facilitate development of optimal RSV fusion inhibitors. PMID:26641933

  7. Evaluation of Encapsulated Inhibitor for Autonomous Corrosion Protection

    NASA Technical Reports Server (NTRS)

    Johnsey, M. N.; Li, W.; Buhrow, J. W.; Calle, L. M.; Pearman, B. P.; Zhang, X.

    2015-01-01

    This work concerns the development of smart coating technologies based on microencapsulation for the autonomous control of corrosion. Microencapsulation allows the incorporation of corrosion inhibitors into coating which provides protection through corrosion-controlled release of these inhibitors.One critical aspect of a corrosion protective smart coating is the selection of corrosion inhibitor for encapsulation and comparison of the inhibitor function before and after encapsulation. For this purpose, a systematic approach is being used to evaluate free and encapsulated corrosion inhibitors by salt immersion. Visual, optical microscope, and Scanning Electron Microscope (with low-angle backscatter electron detector) are used to evaluate these inhibitors. It has been found that the combination of different characterization tools provide an effective method for evaluation of early stage localized corrosion and the effectiveness of corrosion inhibitors.

  8. Sirtuins are Unaffected by PARP Inhibitors Containing Planar Nicotinamide Bioisosteres.

    PubMed

    Ekblad, Torun; Schüler, Herwig

    2016-03-01

    PARP-family ADP-ribosyltransferases (PARPs) and sirtuin deacetylases all use NAD(+) as cosubstrate for ADP-ribosyl transfer. PARP inhibitors are important research tools and several are being evaluated in cancer treatment. With the exception of a few tankyrase inhibitors, all current PARP inhibitors mimic the nicotinamide moiety in NAD(+) and block the nicotinamide binding pocket. We report here that while the activities of the four human sirtuin isoforms SIRT1, SIRT2, SIRT3 and SIRT6 are blocked by sirtuin inhibitor Ex527 in vitro, they are unaffected by the seven clinical and commonly used PARP inhibitors niraparib, olaparib, rucaparib, talazoparib, veliparib, PJ34, and XAV939. These findings indicate that PARP inhibitors containing planar nicotinamide mimetics do not bind to sirtuin cofactor sites. In conclusion, a simple commercially available assay can be used to rule out interference of novel PARP inhibitors with sirtuin NAD(+) binding. PMID:26518726

  9. Sulfatase inhibitors for recidivist breast cancer treatment: A chemical review.

    PubMed

    Shah, Ramanpreet; Singh, Jatinder; Singh, Dhandeep; Jaggi, Amteshwar Singh; Singh, Nirmal

    2016-05-23

    Steroid sulfatase (STS) plays a momentous role in the conversion of sulfated steroids, which are biologically inactive, into biologically active un-sulfated steroid hormones, which support the development and growth of a number of hormone-dependent cancers, including breast cancer. Therefore, inhibitors of STS are supposed to be potential drugs for the treatment of breast and other steroid-dependent cancers. The present review concentrates on broad chemical classification of steroid sulfatase inhibitors. The inhibitors reviewed are classified into four main categories: Steroid sulfamate based inhibitors; Steroid non-sulfamate based inhibitors; Non-steroidal sulfamate based inhibitors; Non-steroidal non-sulfamate based inhibitors. A succinct overview of current treatment of cancer, estradiol precursors, STS enzyme and its role in breast cancer is herein described. PMID:26974384

  10. Platelet C1- inhibitor. A secreted alpha-granule protein.

    PubMed Central

    Schmaier, A H; Smith, P M; Colman, R W

    1985-01-01

    In order to characterize which proteins of the contact phase of coagulation interact with platelets, human platelets were studied immunochemically and functionally to determine if they contain C1- inhibitor. By means of monospecific antibody to C1- inhibitor, a competitive enzyme-linked immunosorbent assay (CELISA) was developed to measure directly platelet C1- inhibitor. With the CELISA, from 33 to 115 ng of C1- inhibitor antigen per 10(8) platelets from 15 normal donors was quantified in lysates of washed human platelets solubilized in nonionic detergent. The mean concentration in 10(8) platelets was 62 +/- 33 ng (SD). Plasma C1- inhibitor either in the platelet suspension medium or on the surface of the platelets could account for only from 6.5 to 16% of the total antigen measured in the solubilized platelets. Upon functional studies, platelets contained 84 +/- 36 ng (SD) of C1- inhibitor activity in 10(8) platelets. As assessed by the CELISA, platelet C1- inhibitor antigen was immunochemically identical to plasma and purified C1- inhibitor. In contrast, the mean concentration of platelet C1- inhibitor antigen in platelets from four patients with classical hereditary angioedema was 8.3 ng/10(8) platelets (range, 5.3 to 11.3 ng/10(8) platelets). 25 and 31% of the total platelet C1- inhibitor was secreted without cell lysis from normal platelets after exposure to collagen (20 micrograms/ml) and thrombin (1 U/ml), respectively, and this secretion was blocked by metabolic inhibitors. Platelet subcellular fractionation showed that platelet C1- inhibitor resided mostly in alpha-granules, similar to the location of platelet fibrinogen. Thus, human platelets contained C1- inhibitor, which became available by platelet secretion. The identification of platelet C1- inhibitor suggests that platelets may modulate the activation of the proteins of early blood coagulation and the classical complement pathways. Images PMID:3965505

  11. New Insights Into the Treatment of Glanzmann Thrombasthenia.

    PubMed

    Poon, Man-Chiu; Di Minno, Giovanni; d'Oiron, Roseline; Zotz, Rainer

    2016-04-01

    Glanzmann thrombasthenia (GT) is a rare inherited autosomal recessive bleeding disorder of platelet function caused by a quantitative or qualitative defect of platelet membrane glycoprotein IIb/IIIa (integrin αIIbβ3), a fibrinogen receptor required for platelet aggregation. Bleeds in GT are variable and may be severe and unpredictable. Bleeding not responsive to local and adjunctive measures, as well as surgical procedures, is treated with platelets, recombinant activated factor VII (rFVIIa), or antifibrinolytics, alone or in combination. Although platelets are the standard treatment for GT, their use is associated with the risk of blood-borne infection transmission and may also cause the development of platelet antibodies (to human leukocyte antigens and/or αIIbβ3), potentially resulting in platelet refractoriness. Currently, where rFVIIa is approved for use in GT, this is mostly for patients with platelet antibodies and/or a history of platelet refractoriness. However, data from the prospective Glanzmann's Thrombasthenia Registry (829 bleeds and 206 procedures in 218 GT patients) show that rFVIIa was frequently used in nonsurgical and surgical bleeds, with high efficacy rates, irrespective of platelet antibodies/refractoriness status. The mechanisms underpinning rFVIIa effectiveness in GT have been studied. At therapeutic concentrations, rFVIIa binds to activated platelets and directly activates FX to FXa, resulting in a burst of thrombin generation. Thrombin converts fibrinogen to fibrin and also enhances GT platelet adhesion and aggregation mediated by the newly converted (polymeric) fibrin, leading to primary hemostasis at the wound site. In addition, thrombin improves the final clot structure and activates thrombin-activatable fibrinolysis inhibitor to decrease clot lysis. PMID:26968829

  12. Purification and characterization of elastase-specific inhibitor. Sequence homology with mucus proteinase inhibitor.

    PubMed

    Sallenave, J M; Ryle, A P

    1991-01-01

    Elastase-specific inhibitor (ESI) was purified from sputum of patients with chronic bronchitis and compared with mucus proteinase inhibitor (MPI, BrI) isolated, without the use of affinity chromatography on an enzyme, from non-purulent sputum of a patient with bronchial carcinoma. The N-terminal sequence of 27 residues of the latter was determined and showed serine as the only N-terminus. The partial N-terminal amino-acid sequence of ESI shows some homology with MPI, especially around the reactive site of MPI for human neutrophil elastase. This region could therefore be the reactive site of ESI. The thermodynamic and kinetic constants of the reactions of ESI with human neutrophil elastase and with porcine pancreatic elastase show that ESI is a fast-acting inhibitor. PMID:2039600

  13. Secretory leukoprotease inhibitor: partnering alpha 1-proteinase inhibitor to combat pulmonary inflammation.

    PubMed Central

    Bingle, L.; Tetley, T. D.

    1996-01-01

    Secretory leukoprotease inhibitor (SLPI) is a low molecular weight serine proteinase inhibitor, notably of neutrophil elastase (NE), which is synthesised and secreted by the pulmonary epithelium. SLPI plays an important role in limiting NE-induced pulmonary inflammation and, significantly, it also possesses anti-HIV activity. SLPI is a significant component of the anti-NE shield in the lung which has different reactivity from, and is therefore complementary to, the anti-NE action of alpha 1-proteinase inhibitor (alpha 1-PI). Inhaled recombinant SLPI (rSLPI) could prove beneficial in partnership with alpha 1-PI in the treatment of a number of inflammatory lung disorders including emphysema, chronic bronchitis, cystic fibrosis, and adult respiratory distress syndrome. PMID:8994529

  14. Studies on bacterial cell wall inhibitors. VI. Screening method for the specific inhibitors of peptidoglycan synthesis.

    PubMed

    Omura, S; Tanaka, H; Oiwa, R; Nagai, T; Koyama, Y; Takahashi, Y

    1979-10-01

    A screening method was established for selecting new specific inhibitors of bacterial cell wall peptidoglycan synthesis. In the primary test, culture broths of soil isolates were selected based on relative microbial activity. A culture, to be retained, must be active against Bacillus subtilis and lack activities against Acholeplasma laidawii. In the secondary test, inhibitors of bacterial cell wall synthesis were identified by their ability to prevent the incorporation of meso-[3H]diaminopimelic acid but not to prevent the incorporation of L-[4C]leucine into the acid-insoluble macromolecular fraction of growing cells of Bacillus sp. ATCC 21206 (Dpm-). As the tertiary test, inhibitors with molecular weights under 1,000 were selected by passage through a Diaflo UM-2 membrane. By this screening procedure, six known antibiotics and one new one were picked out from ten thousand soil isolates. PMID:528376

  15. Protocol for rational design of covalently interacting inhibitors.

    PubMed

    Schmidt, Thomas C; Welker, Armin; Rieger, Max; Sahu, Prabhat K; Sotriffer, Christoph A; Schirmeister, Tanja; Engels, Bernd

    2014-10-20

    The inhibition potencies of covalent inhibitors mainly result from the formation of a covalent bond to the enzyme during the inhibition mechanism. This class of inhibitors has essentially been ignored in previous target-directed drug discovery projects because of concerns about possible side effects. However, their advantages, such as higher binding energies and longer drug-target residence times moved them into the focus of recent investigations. While the rational design of non-covalent inhibitors became standard the corresponding design of covalent inhibitors is still in its early stages. Potent covalent inhibitors can be retrieved from large compound libraries by covalent docking approaches but protocols are missing that can reliably predict the influence of variations in the substitution pattern on the affinity and/or reactivity of a given covalent inhibitor. Hence, the wanted property profile can only be obtained from trial-and-error proceedings. This paper presents an appropriate protocol which is able to predict improved covalent inhibitors. It uses hybrid approaches, which mix quantum mechanical (QM) and molecular mechanical (MM) methods to predict variations in the reactivity of the inhibitor. They are also used to compute the required information about the non-covalent enzyme-inhibitor complex. Docking tools are employed to improve the inhibitor with respect to the non-covalent interactions formed in the binding site. PMID:25251382

  16. Inhibitor development in non-severe haemophilia across Europe.

    PubMed

    Fischer, Kathelijn; Iorio, Alfonso; Lassila, Riitta; Peyvandi, Flora; Calizzani, Gabriele; Gatt, Alex; Lambert, Thierry; Windyga, Jerzy; Gilman, Estelle A; Hollingsworth, R; Makris, Michael

    2015-10-01

    Evidence about inhibitor formation in non-severe haemophilia and the potential role for clotting factor concentrate type is scant. It was the aim of this study to report inhibitor development in non-severe haemophilia patients enrolled in the European Haemophilia Safety Surveillance (EUHASS) study. Inhibitors are reported quarterly and total treated patients annually. Incidence rates and 95% confidence intervals (95% CI) were calculated according to diagnosis and concentrate used. Between 1-10-2008 and 31-12-2012, 68 centres reported on 7,969 patients with non-severe haemophilia A and 1,863 patients with non-severe haemophilia B. For haemophilia A, 37 inhibitors occurred in 8,622 treatment years, resulting in an inhibitor rate of 0.43/100 treatment years (95% CI 0.30-0.59). Inhibitors occurred at a median age of 35 years, after a median of 38 exposure days (EDs; P25-P75: 20-80); with 72% occurring within the first 50 EDs. In haemophilia B, one inhibitor was detected in 2,149 treatment years, resulting in an inhibitor rate of 0.05/100 years (95% CI 0.001-0.26). This inhibitor developed at the age of six years, after six EDs. The rate of inhibitors appeared similar across recombinant and plasma derived factor VIII (FVIII) concentrates. Rates for individual concentrates could not be calculated at this stage due to low number of events. In conclusion, inhibitors in non-severe haemophilia occur three times more frequently than in previously treated patients with severe haemophilia at a rate of 0.43/100 patient years (haemophilia A) and 0.05/100 years (haemophilia B). Although the majority of inhibitors developed in the first 50 EDs, inhibitor development continued with increasing exposure to FVIII. PMID:26293381

  17. Assessing the emetic potential of PDE4 inhibitors in rats.

    PubMed

    Robichaud, A; Savoie, C; Stamatiou, P B; Lachance, N; Jolicoeur, P; Rasori, R; Chan, C C

    2002-01-01

    1. Type 4 phosphodiesterase (PDE4) inhibitors mimic the pharmacological actions of alpha(2)-adrenoceptor antagonists. This has been postulated as the mechanism by which PDE4 inhibitors induce emesis and was also demonstrated by their ability to reverse xylazine/ketamine-induced anaesthesia. We further characterized this latter effect since it appears to reflect the emetic potential of PDE4 inhibitors. 2. Selective inhibitors of PDE 1, 2, 3, 4 and 5 were studied in rats, on the duration of anaesthesia induced by the combination of xylazine (10 mg kg(-1), i.m.) and ketamine (10 mg kg(-1), i.m.). PMNPQ (i.e. 6-(4-pyridylmethyl)-8-(3-nitrophenyl)quinoline) - PDE4 inhibitor: 0.01 - 3 mg kg(-1)), like MK-912 (alpha(2)-adrenoceptor antagonist: 0.01 - 3 mg kg(-1)), dose-dependently reduced the duration of anaesthesia. In contrast, vinpocetine (PDE1 inhibitor), EHNA (PDE2 inhibitor), milrinone (PDE3 inhibitor) and zaprinast (PDE5 inhibitor) had no significant effect at the doses tested (1 - 10 mg kg(-1)). Analysis of plasma and cerebrospinal fluid (CSF) of treated animals confirmed the absorption and distribution to the brain of the inactive inhibitors. 3. Neither MK-912 (3 mg kg(-1)) nor PMNPQ (0.1 - 1 mg kg(-1)) altered the duration of anaesthesia induced via a non-alpha(2)-adrenoceptor pathway (sodium pentobarbitone 50 mg kg(-1), i.p.). 4. Central NK(1) receptors are involved in PDE4 inhibitor-induced emesis. Consistently, [sar(9), Met(O(2))(11)]-substance P (NK(1) receptor agonist, 6 microg i.c.v.) reduced the duration of anaesthesia induced by xylazine/ketamine. 5. In summary, this model is functionally coupled to PDE4, specific to alpha(2)-adrenoceptors and relevant to PDE4 inhibitor-induced emesis. It therefore provides a novel way of evaluating the emetic potential of PDE4 inhibitors in rats. PMID:11786486

  18. Guanine deaminase inhibitor from rat liver. Isolation and characterization.

    PubMed

    Ali, S; Sitaramayya, A; Kumar, K S; Krishnan, P S

    1974-01-01

    1. An inhibitor of cytoplasmic guanine deaminase of rat liver was isolated from liver ;heavy mitochondrial' fraction after freezing and thawing and treatment with Triton X-100. 2. Submitochondrial fractionation revealed that the inhibitor was localized in the outer-membrane fraction. 3. The method of purification of inhibitor, involving precipitation with (NH(4))(2)SO(4) and chromatography on DEAE-cellulose, its precipitability by trichloroacetic acid and the pattern of absorption in the u.v. indicated that the inhibitor was a protein. In confirmation, tryptic digestion of the isolated material resulted in destruction of the inhibitor activity. The inhibitor was stable to acid, but labile to heat. 4. The isolated inhibitor required phosphatidylcholine (lecithin) for activity. Phosphatidylcholine also partially protected the inhibitor against heat inactivation. 5. When detergent treatment was omitted, the inhibitor activity of frozen mitochondria was precipitated by (NH(4))(2)SO(4) in a fully active form without supplementation with phosphatidylcholine, indicating that Triton X-100 ruptured the linkage between inhibitor and lipid. 6. A reconstituted sample of inhibitor-phosphatidylcholine complex was precipitated in a fully active form by dialysis against 2-mercaptoethanol, but treatment of the precipitate with NaCl yielded an extract which was inactive unless supplemented with fresh phosphatidylcholine. 7. We interpret the results as evidence that the inhibitor was present in vivo as a lipoprotein and that once the complex was dissociated by the action of detergent and the protein precipitated, there was an absolute need for exogenous phosphatidylcholine for its activity. The manner in which inhibitor associated with the outer membrane of rat liver mitochondria might regulate the activity of the enzyme in the supernatant has been suggested. PMID:4821397

  19. Structural selectivity of human SGLT inhibitors

    PubMed Central

    Hummel, Charles S.; Lu, Chuan; Liu, Jie; Ghezzi, Chiari; Hirayama, Bruce A.; Loo, Donald D. F.; Kepe, Vladimir; Barrio, Jorge R.

    2012-01-01

    Human Na+-d-glucose cotransporter (hSGLT) inhibitors constitute the newest class of diabetes drugs, blocking up to 50% of renal glucose reabsorption in vivo. These drugs have potential for widespread use in the diabetes epidemic, but how they work at a molecular level is poorly understood. Here, we use electrophysiological methods to assess how they block Na+-d-glucose cotransporter SGLT1 and SGLT2 expressed in human embryonic kidney 293T (HEK-293T) cells and compared them to the classic SGLT inhibitor phlorizin. Dapagliflozin [(1S)-1,5,5-anhydro-1-C-{4-chloro-3-[(4-ethoxyphenyl)methyl]phenyl}-d-glucitol], two structural analogs, and the aglycones of phlorizin and dapagliflozin were investigated in detail. Dapagliflozin and fluoro-dapagliflozin [(1S)-1,5-anhydro-1-C-{4-chloro-3-[(4-ethoxyphenyl)methyl]phenyl}-4-F-4-deoxy-d-glucitol] blocked glucose transport and glucose-coupled currents with ≈100-fold specificity for hSGLT2 (Ki = 6 nM) over hSGLT1 (Ki = 400 nM). As galactose is a poor substrate for SGLT2, it was surprising that galacto-dapagliflozin [(1S)-1,5-anhydro-1-C-{4-chloro-3-[(4-ethoxyphenyl)methyl]phenyl}-d-galactitol] was a selective inhibitor of hSGLT2, but was less potent than dapagliflozin for both transporters (hSGLT2 Ki = 25 nM, hSGLT1 Ki = 25,000 nM). Phlorizin and galacto-dapagliflozin rapidly dissociated from SGLT2 [half-time off rate (t1/2,Off) ≈ 20–30 s], while dapagliflozin and fluoro-dapagliflozin dissociated from hSGLT2 at a rate 10-fold slower (t1/2,Off ≥ 180 s). Phlorizin was unable to exchange with dapagliflozin bound to hSGLT2. In contrast, dapagliflozin, fluoro-dapagliflozin, and galacto-dapagliflozin dissociated quickly from hSGLT1 (t1/2,Off = 1–2 s), and phlorizin readily exchanged with dapagliflozin bound to hSGLT1. The aglycones of phlorizin and dapagliflozin were poor inhibitors of both hSGLT2 and hSGLT1 with Ki values > 100 μM. These results show that inhibitor binding to SGLTs is composed of two synergistic forces

  20. Kynurenine Aminotransferase Isozyme Inhibitors: A Review

    PubMed Central

    Nematollahi, Alireza; Sun, Guanchen; Jayawickrama, Gayan S.; Church, W. Bret

    2016-01-01

    Kynurenine aminotransferase isozymes (KATs 1–4) are members of the pyridoxal-5’-phosphate (PLP)-dependent enzyme family, which catalyse the permanent conversion of l-kynurenine (l-KYN) to kynurenic acid (KYNA), a known neuroactive agent. As KATs are found in the mammalian brain and have key roles in the kynurenine pathway, involved in different categories of central nervous system (CNS) diseases, the KATs are prominent targets in the quest to treat neurodegenerative and cognitive impairment disorders. Recent studies suggest that inhibiting these enzymes would produce effects beneficial to patients with these conditions, as abnormally high levels of KYNA are observed. KAT-1 and KAT-3 share the highest sequence similarity of the isozymes in this family, and their active site pockets are also similar. Importantly, KAT-2 has the major role of kynurenic acid production (70%) in the human brain, and it is considered therefore that suitable inhibition of this isozyme would be most effective in managing major aspects of CNS diseases. Human KAT-2 inhibitors have been developed, but the most potent of them, chosen for further investigations, did not proceed in clinical studies due to the cross toxicity caused by their irreversible interaction with PLP, the required cofactor of the KAT isozymes, and any other PLP-dependent enzymes. As a consequence of the possibility of extensive undesirable adverse effects, it is also important to pursue KAT inhibitors that reversibly inhibit KATs and to include a strategy that seeks compounds likely to achieve substantial interaction with regions of the active site other than the PLP. The main purpose of this treatise is to review the recent developments with the inhibitors of KAT isozymes. This treatise also includes analyses of their crystallographic structures in complex with this enzyme family, which provides further insight for researchers in this and related studies. PMID:27314340

  1. MAO-inhibitors in Parkinson's Disease

    PubMed Central

    Laux, Gerd

    2011-01-01

    Monoamine oxidase inhibitors (MAO-I) belong to the earliest drugs tried in Parkinson's disease (PD). They have been used with or without levodopa (L-DOPA). Non-selective MAO-I due to their side-effect/adverse reaction profile, like tranylcypromine have limited use in the treatment of depression in PD, while selective, reversible MAO-A inhibitors are recommended due to their easier clinical handling. For the treatment of akinesia and motor fluctuations selective irreversible MAO-B inhibitors selegiline and rasagiline are recommended. They are safe and well tolerated at the recommended daily doses. Their main differences are related to (1) metabolism, (2) interaction with CYP-enzymes and (3) quantitative properties at the molecular biological/genetic level. Rasagiline is more potent in clinical practise and has a hypothesis driven more favourable side effect/adverse reaction profile due to its metabolism to aminoindan. Both selegiline and rasagiline have a neuroprotective and neurorestaurative potential. A head-to head clinical trial would be of utmost interest from both the clinical outcome and a hypothesis-driven point of view. Selegiline is available as tablet and melting tablet for PD and as transdermal selegiline for depression, while rasagiline is marketed as tablet for PD. In general, the clinical use of MAO-I nowadays is underestimated. There should be more efforts to evaluate their clinical potency as antidepressants and antidementive drugs in addition to the final proof of their disease-modifying potential. In line with this are recent innovative developments of MAO-I plus inhibition of acetylcholine esterase for Alzheimer's disease as well as combined MAO-I and iron chelation for PD. PMID:22110357

  2. Sifuvirtide, a potent HIV fusion inhibitor peptide

    SciTech Connect

    Wang, Rui-Rui; Yang, Liu-Meng; Wang, Yun-Hua; Pang, Wei; Tam, Siu-Cheung; Tien, Po; Zheng, Yong-Tang

    2009-05-08

    Enfuvirtide (ENF) is currently the only FDA approved HIV fusion inhibitor in clinical use. Searching for more drugs in this category with higher efficacy and lower toxicity seems to be a logical next step. In line with this objective, a synthetic peptide with 36 amino acid residues, called Sifuvirtide (SFT), was designed based on the crystal structure of gp41. In this study, we show that SFT is a potent anti-HIV agent with relatively low cytotoxicity. SFT was found to inhibit replication of all tested HIV strains. The effective concentrations that inhibited 50% viral replication (EC{sub 50}), as determined in all tested strains, were either comparable or lower than benchmark values derived from well-known anti-HIV drugs like ENF or AZT, while the cytotoxic concentrations causing 50% cell death (CC{sub 50}) were relatively high, rendering it an ideal anti-HIV agent. A GST-pull down assay was performed to confirm that SFT is a fusion inhibitor. Furthermore, the activity of SFT on other targets in the HIV life cycle was also investigated, and all assays showed negative results. To further understand the mechanism of action of HIV peptide inhibitors, resistant variants of HIV-1{sub IIIB} were derived by serial virus passage in the presence of increasing doses of SFT or ENF. The results showed that there was cross-resistance between SFT and ENF. In conclusion, SFT is an ideal anti-HIV agent with high potency and low cytotoxicity, but may exhibit a certain extent of cross-resistance with ENF.

  3. Kynurenine Aminotransferase Isozyme Inhibitors: A Review.

    PubMed

    Nematollahi, Alireza; Sun, Guanchen; Jayawickrama, Gayan S; Church, W Bret

    2016-01-01

    Kynurenine aminotransferase isozymes (KATs 1-4) are members of the pyridoxal-5'-phosphate (PLP)-dependent enzyme family, which catalyse the permanent conversion of l-kynurenine (l-KYN) to kynurenic acid (KYNA), a known neuroactive agent. As KATs are found in the mammalian brain and have key roles in the kynurenine pathway, involved in different categories of central nervous system (CNS) diseases, the KATs are prominent targets in the quest to treat neurodegenerative and cognitive impairment disorders. Recent studies suggest that inhibiting these enzymes would produce effects beneficial to patients with these conditions, as abnormally high levels of KYNA are observed. KAT-1 and KAT-3 share the highest sequence similarity of the isozymes in this family, and their active site pockets are also similar. Importantly, KAT-2 has the major role of kynurenic acid production (70%) in the human brain, and it is considered therefore that suitable inhibition of this isozyme would be most effective in managing major aspects of CNS diseases. Human KAT-2 inhibitors have been developed, but the most potent of them, chosen for further investigations, did not proceed in clinical studies due to the cross toxicity caused by their irreversible interaction with PLP, the required cofactor of the KAT isozymes, and any other PLP-dependent enzymes. As a consequence of the possibility of extensive undesirable adverse effects, it is also important to pursue KAT inhibitors that reversibly inhibit KATs and to include a strategy that seeks compounds likely to achieve substantial interaction with regions of the active site other than the PLP. The main purpose of this treatise is to review the recent developments with the inhibitors of KAT isozymes. This treatise also includes analyses of their crystallographic structures in complex with this enzyme family, which provides further insight for researchers in this and related studies. PMID:27314340

  4. Nanomolar Inhibitors of Trypanosoma brucei RNA Triphosphatase

    PubMed Central

    Smith, Paul; Ho, C. Kiong; Takagi, Yuko; Djaballah, Hakim

    2016-01-01

    ABSTRACT Eukaryal taxa differ with respect to the structure and mechanism of the RNA triphosphatase (RTPase) component of the mRNA capping apparatus. Protozoa, fungi, and certain DNA viruses have a metal-dependent RTPase that belongs to the triphosphate tunnel metalloenzyme (TTM) superfamily. Because the structures, active sites, and chemical mechanisms of the TTM-type RTPases differ from those of mammalian RTPases, the TTM RTPases are potential targets for antiprotozoal, antifungal, and antiviral drug discovery. Here, we employed RNA interference (RNAi) knockdown methods to show that Trypanosoma brucei RTPase Cet1 (TbCet1) is necessary for proliferation of procyclic cells in culture. We then conducted a high-throughput biochemical screen for small-molecule inhibitors of the phosphohydrolase activity of TbCet1. We identified several classes of chemicals—including chlorogenic acids, phenolic glycopyranosides, flavonoids, and other phenolics—that inhibit TbCet1 with nanomolar to low-micromolar 50% inhibitory concentrations (IC50s). We confirmed the activity of these compounds, and tested various analogs thereof, by direct manual assays of TbCet1 phosphohydrolase activity. The most potent nanomolar inhibitors included tetracaffeoylquinic acid, 5-galloylgalloylquinic acid, pentagalloylglucose, rosmarinic acid, and miquelianin. TbCet1 inhibitors were less active (or inactive) against the orthologous TTM-type RTPases of mimivirus, baculovirus, and budding yeast (Saccharomyces cerevisiae). Our results affirm that a TTM RTPase is subject to potent inhibition by small molecules, with the caveat that parallel screens against TTM RTPases from multiple different pathogens may be required to fully probe the chemical space of TTM inhibition. PMID:26908574

  5. Tools for Characterizing Bacterial Protein Synthesis Inhibitors

    PubMed Central

    Orelle, Cédric; Carlson, Skylar; Kaushal, Bindiya; Almutairi, Mashal M.; Liu, Haipeng; Ochabowicz, Anna; Quan, Selwyn; Pham, Van Cuong; Squires, Catherine L.; Murphy, Brian T.

    2013-01-01

    Many antibiotics inhibit the growth of sensitive bacteria by interfering with ribosome function. However, discovery of new protein synthesis inhibitors is curbed by the lack of facile techniques capable of readily identifying antibiotic target sites and modes of action. Furthermore, the frequent rediscovery of known antibiotic scaffolds, especially in natural product extracts, is time-consuming and expensive and diverts resources that could be used toward the isolation of novel lead molecules. In order to avoid these pitfalls and improve the process of dereplication of chemically complex extracts, we designed a two-pronged approach for the characterization of inhibitors of protein synthesis (ChIPS) that is suitable for the rapid identification of the site and mode of action on the bacterial ribosome. First, we engineered antibiotic-hypersensitive Escherichia coli strains that contain only one rRNA operon. These strains are used for the rapid isolation of resistance mutants in which rRNA mutations identify the site of the antibiotic action. Second, we show that patterns of drug-induced ribosome stalling on mRNA, monitored by primer extension, can be used to elucidate the mode of antibiotic action. These analyses can be performed within a few days and provide a rapid and efficient approach for identifying the site and mode of action of translation inhibitors targeting the bacterial ribosome. Both techniques were validated using a bacterial strain whose culture extract, composed of unknown metabolites, exhibited protein synthesis inhibitory activity; we were able to rapidly detect the presence of the antibiotic chloramphenicol. PMID:24041905

  6. Ability of the Met Kinase Inhibitor Crizotinib and New Generation EGFR Inhibitors to Overcome Resistance to EGFR Inhibitors

    PubMed Central

    Nanjo, Shigeki; Yamada, Tadaaki; Nishihara, Hiroshi; Takeuchi, Shinji; Sano, Takako; Nakagawa, Takayuki; Ishikawa, Daisuke; Zhao, Lu; Ebi, Hiromichi; Yasumoto, Kazuo; Matsumoto, Kunio; Yano, Seiji

    2013-01-01

    Purpose Although EGF receptor tyrosine kinase inhibitors (EGFR-TKI) have shown dramatic effects against EGFR mutant lung cancer, patients ultimately develop resistance by multiple mechanisms. We therefore assessed the ability of combined treatment with the Met inhibitor crizotinib and new generation EGFR-TKIs to overcome resistance to first-generation EGFR-TKIs. Experimental Design Lung cancer cell lines made resistant to EGFR-TKIs by the gatekeeper EGFR-T790M mutation, Met amplification, and HGF overexpression and mice with tumors induced by these cells were treated with crizotinib and a new generation EGFR-TKI. Results The new generation EGFR-TKI inhibited the growth of lung cancer cells containing the gatekeeper EGFR-T790M mutation, but did not inhibit the growth of cells with Met amplification or HGF overexpression. In contrast, combined therapy with crizotinib plus afatinib or WZ4002 was effective against all three types of cells, inhibiting EGFR and Met phosphorylation and their downstream molecules. Crizotinib combined with afatinib or WZ4002 potently inhibited the growth of mouse tumors induced by these lung cancer cell lines. However, the combination of high dose crizotinib and afatinib, but not WZ4002, triggered severe adverse events. Conclusions Our results suggest that the dual blockade of mutant EGFR and Met by crizotinib and a new generation EGFR-TKI may be promising for overcoming resistance to reversible EGFR-TKIs but careful assessment is warranted clinically. PMID:24386407

  7. Inhibitors of glycogen synthase 3 kinase

    DOEpatents

    Schultz, Peter; Ring, David B.; Harrison, Stephen D.; Bray, Andrew M.

    2006-05-30

    Compounds of formula 1: ##STR00001## wherein R.sub.1 is alkyl, cycloalkyl, aryl, aralkyl, heteroaryl, or heteroaralkyl, substituted with 0 3 substituents selected from lower alkyl, halo, hydroxy, lower alkoxy, amino, lower alkyl-amino, and nitro; R.sub.2 is hydroxy, amino, or lower alkoxy; R.sub.3 is H, lower alkyl, lower acyl, lower alkoxy-acyl, or amino-acyl; R.sub.4 is H or lower alkyl; and pharmaceutically acceptable salts and esters thereof; are effective inhibitors of GSK3.

  8. Bioconversion of lignocellulose: inhibitors and detoxification

    PubMed Central

    2013-01-01

    Bioconversion of lignocellulose by microbial fermentation is typically preceded by an acidic thermochemical pretreatment step designed to facilitate enzymatic hydrolysis of cellulose. Substances formed during the pretreatment of the lignocellulosic feedstock inhibit enzymatic hydrolysis as well as microbial fermentation steps. This review focuses on inhibitors from lignocellulosic feedstocks and how conditioning of slurries and hydrolysates can be used to alleviate inhibition problems. Novel developments in the area include chemical in-situ detoxification by using reducing agents, and methods that improve the performance of both enzymatic and microbial biocatalysts. PMID:23356676

  9. PDE-10A inhibitors as insulin secretagogues.

    PubMed

    Cantin, Louis-David; Magnuson, Steven; Gunn, David; Barucci, Nicole; Breuhaus, Marina; Bullock, William H; Burke, Jennifer; Claus, Thomas H; Daly, Michelle; Decarr, Lynn; Gore-Willse, Ann; Hoover-Litty, Helana; Kumarasinghe, Ellalahewage S; Li, Yaxin; Liang, Sidney X; Livingston, James N; Lowinger, Timothy; Macdougall, Margit; Ogutu, Herbert O; Olague, Alan; Ott-Morgan, Ronda; Schoenleber, Robert W; Tersteegen, Adrian; Wickens, Philip; Zhang, Zhonghua; Zhu, Jian; Zhu, Lei; Sweet, Laurel J

    2007-05-15

    Modulation of cAMP levels has been linked to insulin secretion in preclinical animal models and in humans. The high expression of PDE-10A in pancreatic islets suggested that inhibition of this enzyme may provide the necessary modulation to elicit increased insulin secretion. Using an HTS approach, we have identified quinoline-based PDE-10A inhibitors as insulin secretagogues in vitro. Optimized compounds were evaluated in vivo where improvements in glucose tolerance and increases in insulin secretion were measured. PMID:17400452

  10. Protease inhibitors targeting coronavirus and filovirus entry.

    PubMed

    Zhou, Yanchen; Vedantham, Punitha; Lu, Kai; Agudelo, Juliet; Carrion, Ricardo; Nunneley, Jerritt W; Barnard, Dale; Pöhlmann, Stefan; McKerrow, James H; Renslo, Adam R; Simmons, Graham

    2015-04-01

    In order to gain entry into cells, diverse viruses, including Ebola virus, SARS-coronavirus and the emerging MERS-coronavirus, depend on activation of their envelope glycoproteins by host cell proteases. The respective enzymes are thus excellent targets for antiviral intervention. In cell culture, activation of Ebola virus, as well as SARS- and MERS-coronavirus can be accomplished by the endosomal cysteine proteases, cathepsin L (CTSL) and cathepsin B (CTSB). In addition, SARS- and MERS-coronavirus can use serine proteases localized at the cell surface, for their activation. However, it is currently unclear which protease(s) facilitate viral spread in the infected host. We report here that the cysteine protease inhibitor K11777, ((2S)-N-[(1E,3S)-1-(benzenesulfonyl)-5-phenylpent-1-en-3-yl]-2-{[(E)-4-methylpiperazine-1-carbonyl]amino}-3-phenylpropanamide) and closely-related vinylsulfones act as broad-spectrum antivirals by targeting cathepsin-mediated cell entry. K11777 is already in advanced stages of development for a number of parasitic diseases, such as Chagas disease, and has proven to be safe and effective in a range of animal models. K11777 inhibition of SARS-CoV and Ebola virus entry was observed in the sub-nanomolar range. In order to assess whether cysteine or serine proteases promote viral spread in the host, we compared the antiviral activity of an optimized K11777-derivative with that of camostat, an inhibitor of TMPRSS2 and related serine proteases. Employing a pathogenic animal model of SARS-CoV infection, we demonstrated that viral spread and pathogenesis of SARS-CoV is driven by serine rather than cysteine proteases and can be effectively prevented by camostat. Camostat has been clinically used to treat chronic pancreatitis, and thus represents an exciting potential therapeutic for respiratory coronavirus infections. Our results indicate that camostat, or similar serine protease inhibitors, might be an effective option for treatment of SARS and

  11. Improving cancer immunotherapy with DNA methyltransferase inhibitors.

    PubMed

    Saleh, Mohammad H; Wang, Lei; Goldberg, Michael S

    2016-07-01

    Immunotherapy confers durable clinical benefit to melanoma, lung, and kidney cancer patients. Challengingly, most other solid tumors, including ovarian carcinoma, are not particularly responsive to immunotherapy, so combination with a complementary therapy may be beneficial. Recent findings suggest that epigenetic modifying drugs can prime antitumor immunity by increasing expression of tumor-associated antigens, chemokines, and activating ligands by cancer cells as well as cytokines by immune cells. This review, drawing from both preclinical and clinical data, describes some of the mechanisms of action that enable DNA methyltransferase inhibitors to facilitate the establishment of antitumor immunity. PMID:26646852

  12. Inside HDACs with more selective HDAC inhibitors.

    PubMed

    Roche, Joëlle; Bertrand, Philippe

    2016-10-01

    Inhibitors of histone deacetylases (HDACs) are nowadays part of the therapeutic arsenal mainly against cancers, with four compounds approved by the Food and Drug Administration. During the last five years, several groups have made continuous efforts to improve this class of compounds, designing more selective compounds or compounds with multiple capacities. After a survey of the HDAC biology and structures, this review summarizes the results of the chemists working in this field, and highlights when possible the behavior of the molecules inside their targets. PMID:27318122

  13. Recent Progress in Histone Demethylase Inhibitors.

    PubMed

    McAllister, Tom E; England, Katherine S; Hopkinson, Richard J; Brennan, Paul E; Kawamura, Akane; Schofield, Christopher J

    2016-02-25

    There is increasing interest in targeting histone N-methyl-lysine demethylases (KDMs) with small molecules both for the generation of probes for target exploration and for therapeutic purposes. Here we update on previous reviews on the inhibition of the lysine-specific demethylases (LSDs or KDM1s) and JmjC families of N-methyl-lysine demethylases (JmjC KDMs, KDM2-7), focusing on the academic and patent literature from 2014 to date. We also highlight recent biochemical, biological, and structural studies which are relevant to KDM inhibitor development. PMID:26710088

  14. Inhibitors of glycogen synthase 3 kinase

    DOEpatents

    Schultz, Peter; Ring, David B.; Harrison, Stephen D.; Bray, Andrew M.

    2000-01-01

    Compounds of formula 1: ##STR1## wherein R.sub.1 is alkyl, cycloalkyl, aryl, aralkyl, heteroaryl, or heteroaralkyl, substituted with 0-3 substituents selected from lower alkyl, halo, hydroxy, lower alkoxy, amino, lower alkyl-amino, and nitro; R.sub.2 is hydroxy, amino, or lower alkoxy; R.sub.3 is H, lower alkyl, lower acyl, lower alkoxy-acyl, or amnino-acyl; R.sub.4 is H or lower alkyl; and pharmaceutically acceptable salts and esters thereof; are effective inhibitors of GSK3.

  15. Chlorolissoclimides: New inhibitors of eukaryotic protein synthesis

    PubMed Central

    Robert, Francis; Gao, Hong Qing; Donia, Marwa; Merrick, William C.; Hamann, Mark T.; Pelletier, Jerry

    2006-01-01

    Lissoclimides are cytotoxic compounds produced by shell-less molluscs through chemical secretions to deter predators. Chlorinated lissoclimides were identified as the active component of a marine extract from Pleurobranchus forskalii found during a high-throughput screening campaign to characterize new protein synthesis inhibitors. It was demonstrated that these compounds inhibit protein synthesis in vitro, in extracts prepared from mammalian and plant cells, as well as in vivo against mammalian cells. Our results suggest that they block translation elongation by inhibiting translocation, leading to an accumulation of ribosomes on mRNA. These data provide a rationale for the cytotoxic nature of this class of small molecule natural products. PMID:16540697

  16. KIDFamMap: a database of kinase-inhibitor-disease family maps for kinase inhibitor selectivity and binding mechanisms.

    PubMed

    Chiu, Yi-Yuan; Lin, Chih-Ta; Huang, Jhang-Wei; Hsu, Kai-Cheng; Tseng, Jen-Hu; You, Syuan-Ren; Yang, Jinn-Moon

    2013-01-01

    Kinases play central roles in signaling pathways and are promising therapeutic targets for many diseases. Designing selective kinase inhibitors is an emergent and challenging task, because kinases share an evolutionary conserved ATP-binding site. KIDFamMap (http://gemdock.life.nctu.edu.tw/KIDFamMap/) is the first database to explore kinase-inhibitor families (KIFs) and kinase-inhibitor-disease (KID) relationships for kinase inhibitor selectivity and mechanisms. This database includes 1208 KIFs, 962 KIDs, 55 603 kinase-inhibitor interactions (KIIs), 35 788 kinase inhibitors, 399 human protein kinases, 339 diseases and 638 disease allelic variants. Here, a KIF can be defined as follows: (i) the kinases in the KIF with significant sequence similarity, (ii) the inhibitors in the KIF with significant topology similarity and (iii) the KIIs in the KIF with significant interaction similarity. The KIIs within a KIF are often conserved on some consensus KIDFamMap anchors, which represent conserved interactions between the kinase subsites and consensus moieties of their inhibitors. Our experimental results reveal that the members of a KIF often possess similar inhibition profiles. The KIDFamMap anchors can reflect kinase conformations types, kinase functions and kinase inhibitor selectivity. We believe that KIDFamMap provides biological insights into kinase inhibitor selectivity and binding mechanisms. PMID:23193279

  17. KIDFamMap: a database of kinase-inhibitor-disease family maps for kinase inhibitor selectivity and binding mechanisms

    PubMed Central

    Chiu, Yi-Yuan; Lin, Chih-Ta; Huang, Jhang-Wei; Hsu, Kai-Cheng; Tseng, Jen-Hu; You, Syuan-Ren; Yang, Jinn-Moon

    2013-01-01

    Kinases play central roles in signaling pathways and are promising therapeutic targets for many diseases. Designing selective kinase inhibitors is an emergent and challenging task, because kinases share an evolutionary conserved ATP-binding site. KIDFamMap (http://gemdock.life.nctu.edu.tw/KIDFamMap/) is the first database to explore kinase-inhibitor families (KIFs) and kinase-inhibitor-disease (KID) relationships for kinase inhibitor selectivity and mechanisms. This database includes 1208 KIFs, 962 KIDs, 55 603 kinase-inhibitor interactions (KIIs), 35 788 kinase inhibitors, 399 human protein kinases, 339 diseases and 638 disease allelic variants. Here, a KIF can be defined as follows: (i) the kinases in the KIF with significant sequence similarity, (ii) the inhibitors in the KIF with significant topology similarity and (iii) the KIIs in the KIF with significant interaction similarity. The KIIs within a KIF are often conserved on some consensus KIDFamMap anchors, which represent conserved interactions between the kinase subsites and consensus moieties of their inhibitors. Our experimental results reveal that the members of a KIF often possess similar inhibition profiles. The KIDFamMap anchors can reflect kinase conformations types, kinase functions and kinase inhibitor selectivity. We believe that KIDFamMap provides biological insights into kinase inhibitor selectivity and binding mechanisms. PMID:23193279

  18. Examination of the change in returning molecular weight obtained during inhibitor squeeze treatments using polyacrylate based inhibitors

    SciTech Connect

    Graham, G.M.; Sorbie, K.S.

    1995-11-01

    Scale inhibitors based on small polyelectrolytes are often employed in oilfield scale prevention treatments. These materials are injected into the near-well formation of producers in a scale inhibitor squeeze treatment. When the well is brought back on production, the objective is for the return concentration level of the inhibitor in the produced brine to be at or above a certain threshold level, C{sub t}. This threshold level is the minimum inhibitor concentration required to prevent the formation of mineral carbonate or sulfate scales in that well. The squeeze lifetime depends strongly on the nature of the interaction between the inhibitor and the formation either through an adsorption or precipitation mechanism. Both adsorption and precipitation processes depend on the molecular weight of the scale inhibitor, as well as on a range of other factors. However, polymeric inhibitor species always display some degree of polydispersity (spread of molecular weight). In this paper, the authors examine the effects of molecular weight on adsorption/desorption phenomena for polyacrylate based inhibitor species. This work shows that, in the inhibitor effluent after a squeeze treatment, the molecular weight of the returning inhibitor may be different from that which was injected. For commercially available polymeric inhibitor species, they demonstrate using core floods that preferential retention of higher molecular weight components occurs and preferential desorption of lower molecular weight components is observed. This leads to a gradation in molecular weight in the return profile, which can lead to increased molecular weight components returning as the inhibitor concentration approaches the threshold level. The significance of this observation to field application of polymeric inhibitor species is discussed.

  19. Recent chymase inhibitors and their effects in in vivo models.

    PubMed

    Muto, Tsuyoshi; Fukami, Harukazu

    2002-12-01

    Recent efforts to discover novel chymase inhibitors have produced orally bioavailable compounds. Studies using such inhibitors have shed light on the pathophysiological roles of chymase, eg, a chymase inhibitor has prevented atherosclerosis, restenosis and myocardial infarction in respective animal models. In these cardiovascular diseases, angiotensin I is likely involved as a substrate for chymase. The studies using chymase inhibitors have also shown the potential role of chymase in other diseases, including atopic dermatitis, tissue fibrosis and rheumatoid arthritis; a chymase inhibitor also reduced ischemic reperfusion injury in the small intestine. These results suggest the existence of physiological substrates for chymase other than angiotensin I. Chymase inhibitors are promising for the treatment of cardiovascular as well as inflammatory diseases. PMID:12800055

  20. Enzyme inhibitors in tuber crops and their thermal stability.

    PubMed

    Prathibha, S; Nambisan, B; Leelamma, S

    1995-10-01

    Tubers of Cassava (Manihot esculenta), yams (Dioscorea esculenta), aroids (Amorphophallus campanulatus, Colocasia esculenta, Xanthosoma sagittfolium) and Coleus (Solenostemon rotundifolius) were screened for inhibitory activities against amylase, trypsin and chymotrypsin. Coleus tuber possessed the highest anti-amylase activity, whereas Colocasia tuber was the most potent source of anti-tryptic and anti-chymotryptic activity. Xanthosoma tubers exhibited amylase inhibitory activity and Amorphophallus tubers antiprotease activity. Dioscorea esculenta had low levels of amylase and chymotrypsin inhibitors, while Cassava tubers were totally free of inhibitors. When tubers were processed by pressure cooking, there was significant reduction/complete elimination in inhibitory activity. Partial retention of inhibition was observed in the case of amylase inhibitor in Dioscorea, chymotrypsin inhibitor in Colocasia and trypsin inhibitor in Colocasia, Coleus and Amorphophallus. In vitro experiments on heat stability of the different inhibitors revealed almost similar pattern of inactivation. PMID:8833431

  1. Hepatitis C Virus NS3 Inhibitors: Current and Future Perspectives

    PubMed Central

    Akimitsu, Nobuyoshi

    2013-01-01

    Currently, hepatitis C virus (HCV) infection is considered a serious health-care problem all over the world. A good number of direct-acting antivirals (DAAs) against HCV infection are in clinical progress including NS3-4A protease inhibitors, RNA-dependent RNA polymerase inhibitors, and NS5A inhibitors as well as host targeted inhibitors. Two NS3-4A protease inhibitors (telaprevir and boceprevir) have been recently approved for the treatment of hepatitis C in combination with standard of care (pegylated interferon plus ribavirin). The new therapy has significantly improved sustained virologic response (SVR); however, the adverse effects associated with this therapy are still the main concern. In addition to the emergence of viral resistance, other targets must be continually developed. One such underdeveloped target is the helicase portion of the HCV NS3 protein. This review article summarizes our current understanding of HCV treatment, particularly with those of NS3 inhibitors. PMID:24282816

  2. Secretory leukocyte proteinase inhibitor is a major leukocyte elastase inhibitor in human neutrophils.

    PubMed

    Sallenave, J M; Si Tahar, M; Cox, G; Chignard, M; Gauldie, J

    1997-06-01

    Secretory leukocyte proteinase inhibitor (SLPI) is the main neutrophil elastase (HLE) inhibitor found in the upper airways during pulmonary inflammation. It has been shown to be synthesized and secreted in vitro by epithelial cells and has been localized in tracheal glands and bronchiolar epithelial cells by immunocytochemistry. In this study, using immunodetection and immunopurification techniques with specific anti-SLPI immunoglobulin G (IgG), we show that SLPI is present as a native 14-kDa molecule in neutrophil cytosol. In addition, we demonstrate that SLPI is the major inhibitor of HLE present in neutrophil cytosol because pre-incubation with specific anti-SLPI IgG was able to inhibit completely the anti-HLE activity of the cytosol. SLPI can be secreted (probably in an inactive form) by neutrophils and its secretion is enhanced when the cells are stimulated with phorbol myristate acetate (PMA). Elafin, an elastase-specific inhibitor, is also present in minute amounts in neutrophil cytosol and its secretion can be up-regulated. The presence of SLPI in the cytosol of neutrophils may serve as a protective screen against proteinases spilling from azurophilic granules. An alternative or supplementary role may be the maintenance of a differentiated phenotype. PMID:9201260

  3. The STAT5 inhibitor pimozide decreases survival of chronic myelogenous leukemia cells resistant to kinase inhibitors

    PubMed Central

    Nelson, Erik A.; Walker, Sarah R.; Weisberg, Ellen; Bar-Natan, Michal; Barrett, Rosemary; Gashin, Laurie B.; Terrell, Shariya; Klitgaard, Josephine L.; Santo, Loredana; Addorio, Martha R.; Ebert, Benjamin L.; Griffin, James D.

    2011-01-01

    The transcription factor STAT5 is an essential mediator of the pathogenesis of chronic myelogenous leukemia (CML). In CML, the BCR/ABL fusion kinase causes the constitutive activation of STAT5, thereby driving the expression of genes promoting survival. BCR/ABL kinase inhibitors have become the mainstay of therapy for CML, although CML cells can develop resistance through mutations in BCR/ABL. To overcome this problem, we used a cell-based screen to identify drugs that inhibit STAT-dependent gene expression. Using this approach, we identified the psychotropic drug pimozide as a STAT5 inhibitor. Pimozide decreases STAT5 tyrosine phosphorylation, although it does not inhibit BCR/ABL or other tyrosine kinases. Furthermore, pimozide decreases the expression of STAT5 target genes and induces cell cycle arrest and apoptosis in CML cell lines. Pimozide also selectively inhibits colony formation of CD34+ bone marrow cells from CML patients. Importantly, pimozide induces similar effects in the presence of the T315I BCR/ABL mutation that renders the kinase resistant to presently available inhibitors. Simultaneously inhibiting STAT5 with pimozide and the kinase inhibitors imatinib or nilotinib shows enhanced effects in inhibiting STAT5 phosphorylation and in inducing apoptosis. Thus, targeting STAT5 may be an effective strategy for the treatment of CML and other myeloproliferative diseases. PMID:21233313

  4. Complex polysaccharides as PCR inhibitors in feces: Helicobacter pylori model.

    PubMed

    Monteiro, L; Bonnemaison, D; Vekris, A; Petry, K G; Bonnet, J; Vidal, R; Cabrita, J; Mégraud, F

    1997-04-01

    A model was developed to study inhibitors present in feces which prevent the use of PCR for the detection of Helicobacter pylori. A DNA fragment amplified with the same primers as H. pylori was used to spike samples before extraction by a modified QIAamp tissue method. Inhibitors, separated on an Ultrogel AcA44 column, were characterized. Inhibitors in feces are complex polysaccharides possibly originating from vegetable material in the diet. PMID:9157172

  5. Dipeptidyl peptidase-4 inhibitor for steroid-induced diabetes

    PubMed Central

    Yanai, Hidekatsu; Masui, Yoshinori; Yoshikawa, Reo; Kunimatsu, Junwa; Kaneko, Hiroshi

    2010-01-01

    The addition of the dipeptidyl peptidase-4 (DDP-4) inhibitor has been reported to achieve greater improvements in glucose metabolism with fewer adverse events compared to increasing the metformin dose in type 2 diabetic patients. We present a patient with steroid-induced diabetes whose blood glucose levels were ameliorated by the use of the DPP-4 inhibitor, showing that the DPP-4 inhibitors may be an effective and safe oral anti-diabetic drug for steroid-induced diabetes. PMID:21537433

  6. Aromatase inhibitors in men: effects and therapeutic options

    PubMed Central

    2011-01-01

    Aromatase inhibitors effectively delay epiphysial maturation in boys and improve testosterone levels in adult men Therefore, aromatase inhibitors may be used to increase adult height in boys with gonadotropin-independent precocious puberty, idiopathic short stature and constitutional delay of puberty. Long-term efficacy and safety of the use of aromatase inhibitors has not yet been established in males, however, and their routine use is therefore not yet recommended. PMID:21693046

  7. Natural compounds as corrosion inhibitors for highly cycled systems

    SciTech Connect

    Quraishi, M.A.; Farooqi, I.H.; Saini, P.A.

    1999-11-01

    Strict environmental legislations have led to the development of green inhibitors in recent years. In continuation of the authors` research work on development of green inhibitors, they have investigated the aqueous extracts of three plants namely: Azadirachta indica, Punica Granatum and Momordica charantia as corrosion inhibitors for mild steel in 3% NaCl using weight loss and electrochemical methods. All the investigated compounds exhibited excellent corrosion inhibition properties comparable to that of HEDP. Azadirachta showed better scale inhibition effect than HEDP.

  8. Replication and Inhibitors of Enteroviruses and Parechoviruses

    PubMed Central

    van der Linden, Lonneke; Wolthers, Katja C.; van Kuppeveld, Frank J.M.

    2015-01-01

    The Enterovirus (EV) and Parechovirus genera of the picornavirus family include many important human pathogens, including poliovirus, rhinovirus, EV-A71, EV-D68, and human parechoviruses (HPeV). They cause a wide variety of diseases, ranging from a simple common cold to life-threatening diseases such as encephalitis and myocarditis. At the moment, no antiviral therapy is available against these viruses and it is not feasible to develop vaccines against all EVs and HPeVs due to the great number of serotypes. Therefore, a lot of effort is being invested in the development of antiviral drugs. Both viral proteins and host proteins essential for virus replication can be used as targets for virus inhibitors. As such, a good understanding of the complex process of virus replication is pivotal in the design of antiviral strategies goes hand in hand with a good understanding of the complex process of virus replication. In this review, we will give an overview of the current state of knowledge of EV and HPeV replication and how this can be inhibited by small-molecule inhibitors. PMID:26266417

  9. HTCC: Broad Range Inhibitor of Coronavirus Entry

    PubMed Central

    Milewska, Aleksandra; Kaminski, Kamil; Ciejka, Justyna; Kosowicz, Katarzyna; Zeglen, Slawomir; Wojarski, Jacek; Nowakowska, Maria; Szczubiałka, Krzysztof; Pyrc, Krzysztof

    2016-01-01

    To date, six human coronaviruses have been known, all of which are associated with respiratory infections in humans. With the exception of the highly pathogenic SARS and MERS coronaviruses, human coronaviruses (HCoV-NL63, HCoV-OC43, HCoV-229E, and HCoV-HKU1) circulate worldwide and typically cause the common cold. In most cases, infection with these viruses does not lead to severe disease, although acute infections in infants, the elderly, and immunocompromised patients may progress to severe disease requiring hospitalization. Importantly, no drugs against human coronaviruses exist, and only supportive therapy is available. Previously, we proposed the cationically modified chitosan, N-(2-hydroxypropyl)-3-trimethylammonium chitosan chloride (HTCC), and its hydrophobically-modified derivative (HM-HTCC) as potent inhibitors of the coronavirus HCoV-NL63. Here, we show that HTCC inhibits interaction of a virus with its receptor and thus blocks the entry. Further, we demonstrate that HTCC polymers with different degrees of substitution act as effective inhibitors of all low-pathogenic human coronaviruses. PMID:27249425

  10. SGLT2 Inhibitors: Benefit/Risk Balance.

    PubMed

    Scheen, André J

    2016-10-01

    Inhibitors of sodium-glucose cotransporters type 2 (SGLT2) reduce hyperglycemia by increasing urinary glucose excretion. They have been evaluated in patients with type 2 diabetes treated with diet/exercise, metformin, dual oral therapy or insulin. Three agents are available in Europe and the USA (canagliflozin, dapagliflozin, empagliflozin) and others are commercialized in Japan or in clinical development. SGLT2 inhibitors reduce glycated hemoglobin, with a minimal risk of hypoglycemia. They exert favorable effects beyond glucose control with consistent body weight, blood pressure, and serum uric acid reductions. Empagliflozin showed remarkable reductions in cardiovascular/all-cause mortality and in hospitalization for heart failure in patients with previous cardiovascular disease. Positive renal outcomes were also shown with empagliflozin. Mostly reported adverse events are genital mycotic infections, while urinary tract infections and events linked to volume depletion are rather rare. Concern about a risk of ketoacidosis and bone fractures has been recently raised, which deserves caution and further evaluation. PMID:27541294

  11. RNA aptamer inhibitors of a restriction endonuclease

    PubMed Central

    Mondragón, Estefanía; Maher, L. James

    2015-01-01

    Restriction endonucleases (REases) recognize and cleave short palindromic DNA sequences, protecting bacterial cells against bacteriophage infection by attacking foreign DNA. We are interested in the potential of folded RNA to mimic DNA, a concept that might be applied to inhibition of DNA-binding proteins. As a model system, we sought RNA aptamers against the REases BamHI, PacI and KpnI using systematic evolution of ligands by exponential enrichment (SELEX). After 20 rounds of selection under different stringent conditions, we identified the 10 most enriched RNA aptamers for each REase. Aptamers were screened for binding and specificity, and assayed for REase inhibition. We obtained eight high-affinity (Kd ∼12-30 nM) selective competitive inhibitors (IC50 ∼20-150 nM) for KpnI. Predicted RNA secondary structures were confirmed by in-line attack assay and a 38-nt derivative of the best anti-KpnI aptamer was sufficient for inhibition. These competitive inhibitors presumably act as KpnI binding site analogs, but lack the primary consensus KpnI cleavage sequence and are not cleaved by KpnI, making their potential mode of DNA mimicry fascinating. Anti-REase RNA aptamers could have value in studies of REase mechanism and may give clues to a code for designing RNAs that competitively inhibit DNA binding proteins including transcription factors. PMID:26184872

  12. CYP17 inhibitors for prostate cancer therapy

    PubMed Central

    Vasaitis, Tadas S.; Bruno, Robert D.; Njar, Vincent C. O.

    2010-01-01

    Prostate cancer (PC) is now the second most prevalent cause of death in men in the USA and Europe. At present, the major treatment options include surgical or medical castration. These strategies cause ablation of the production of testosterone (T), dihydrotestosterone (DHT) and related androgens by the testes. However, because these procedures do not affect adrenal, prostate and other tissues androgen production, they are often combined with androgen receptor antagonists to block their action. Indeed, recent studies have unequivocally established that in castration-resistant prostate cancer (CRPC) many androgen-regulated genes become re-expressed and tissue androgen levels increase despite low serum levels. Clearly, inhibition of the key enzyme which catalyzes the biosynthesis of androgens from pregnane precursors, 17α-hydroxy/17,20-lyase (hereafter referred to as CYP17) could prevent androgen production from all sources. Thus, total ablation of androgen production by potent CYP17 inhibitors may provide effective treatment of prostate cancer patients. This review highlights the role of androgen biosynthesis in the progression of prostate cancer and the impact of CYP17 inhibitors, such as ketoconazole, abiraterone acetate, VN/124-1 (TOK-001) and TAK-700 in the clinic and in clinical development. PMID:21092758

  13. Entry inhibitors: New advances in HCV treatment

    PubMed Central

    Qian, Xi-Jing; Zhu, Yong-Zhe; Zhao, Ping; Qi, Zhong-Tian

    2016-01-01

    Hepatitis C virus (HCV) infection affects approximately 3% of the world's population and causes chronic liver diseases, including liver fibrosis, cirrhosis, and hepatocellular carcinoma. Although current antiviral therapy comprising direct-acting antivirals (DAAs) can achieve a quite satisfying sustained virological response (SVR) rate, it is still limited by viral resistance, long treatment duration, combined adverse reactions, and high costs. Moreover, the currently marketed antivirals fail to prevent graft reinfections in HCV patients who receive liver transplantations, probably due to the cell-to-cell transmission of the virus, which is also one of the main reasons behind treatment failure. HCV entry is a highly orchestrated process involving initial attachment and binding, post-binding interactions with host cell factors, internalization, and fusion between the virion and the host cell membrane. Together, these processes provide multiple novel and promising targets for antiviral therapy. Most entry inhibitors target host cell components with high genetic barriers and eliminate viral infection from the very beginning of the viral life cycle. In future, the addition of entry inhibitors to a combination of treatment regimens might optimize and widen the prevention and treatment of HCV infection. This review summarizes the molecular mechanisms and prospects of the current preclinical and clinical development of antiviral agents targeting HCV entry. PMID:26733381

  14. Anti-platelet therapy: phosphodiesterase inhibitors

    PubMed Central

    Gresele, Paolo; Momi, Stefania; Falcinelli, Emanuela

    2011-01-01

    Inhibition of platelet aggregation can be achieved either by the blockade of membrane receptors or by interaction with intracellular signalling pathways. Cyclic adenosine 3′,5′-monophosphate (cAMP) and cyclic guanosine 3′,5′-monophosphate (cGMP) are two critical intracellular second messengers provided with strong inhibitory activity on fundamental platelet functions. Phosphodiesterases (PDEs), by catalysing the hydrolysis of cAMP and cGMP, limit the intracellular levels of cyclic nucleotides, thus regulating platelet function. The inhibition of PDEs may therefore exert a strong platelet inhibitory effect. Platelets possess three PDE isoforms (PDE2, PDE3 and PDE5), with different selectivity for cAMP and cGMP. Several nonselective or isoenzyme-selective PDE inhibitors have been developed, and some of them have entered clinical use as antiplatelet agents. This review focuses on the effect of PDE2, PDE3 and PDE5 inhibitors on platelet function and on the evidence for an antithrombotic action of some of them, and in particular of dipyridamole and cilostazol. PMID:21649691

  15. A novel molluscicide, corrosion inhibitor, and dispersant

    SciTech Connect

    Kreuser, R.T.; Vanlaer, A.; Damour, A.

    1997-12-01

    The efficacy of filming amines as corrosion inhibitors and dispersants in steam systems is well-documented. A novel formulation retains these functions of traditional filming amines and adds molluscicide capability for controlling macrofouling in fresh water and sea water. Criteria for this development included low toxicity to mammals and to non-target aquatic species, rapid biodegradation, and multifunctionality. Low mammalian toxicity and lack of other hazards exempt it from reporting requirements under SARA Title 3. Toxicity (LC{sub 50}) levels for rainbow trout and fathead minnow are higher than typical dosage rates. Biodegradation is rapid; half life is 22 hours in river water. By effectively dispersing slimes (along with biofilm, scale, and tubercles), it controls slimes without toxicity to biofilm organisms. As corrosion inhibitor, it reduces the open cell potential of metal surfaces by 50--200 millivolts and retards pitting and crevice corrosion. Its molluscicide activity gradually kills and disperses mussels, clams, and barnacles. The protective film, renewed by dosage for a brief period of time each day, proactively prevents scale and slime deposits and repels settling and adhesion by macrofouling species. Refinement of established technology has produced a multi-functional formulation that is safe to handle and has minimal impact on the environment.

  16. Novel inhibitors of Anthrax edema factor

    PubMed Central

    Chen, Deliang; Misra, Milind; Sower, Laurie; Peterson, Johnny W.; Kellogg, Glen E.; Schein, Catherine H.

    2008-01-01

    Several pathogenic bacteria produce adenylyl cyclase toxins, such as the edema factor (EF) of Bacillus anthracis. These disturb cellular metabolism by catalyzing production of excessive amounts of the regulatory molecule cAMP. Here, a structure-based method, where a 3D- pharmacophore that fit the active site of EF was constructed from fragments, was used to identify non-nucleotide inhibitors of EF. A library of small molecule fragments was docked to the EF- active site in existing crystal structures and those with the highest HINT scores were assembled into a 3D-pharmacophore. About 10,000 compounds, from over 2.7 million compounds in the ZINC database, had a similar molecular framework. These were ranked according to their docking scores, using methodology that was shown to achieve maximum accuracy (i.e., how well the docked position matched the experimentally determined site for ATP analogues in crystal structures of the complex). Finally, 19 diverse compounds with the best AutoDock binding/docking scores were assayed in a cell based assay for their ability to reduce cAMP secretion induced by EF. Four of the test compounds, from different structural groups, inhibited in the low micromolar range. One of these has a core structure common to phosphatase inhibitors previously identified by high-throughput assays of a diversity library. Thus, the fragment based pharmacophore identified a small number of diverse compounds for assay, and greatly enhanced the selection process of advanced lead compounds for combinatorial design. PMID:18620864

  17. Undecaprenyl diphosphate synthase inhibitors: antibacterial drug leads.

    PubMed

    Sinko, William; Wang, Yang; Zhu, Wei; Zhang, Yonghui; Feixas, Ferran; Cox, Courtney L; Mitchell, Douglas A; Oldfield, Eric; McCammon, J Andrew

    2014-07-10

    There is a significant need for new antibiotics due to the rise in drug resistance. Drugs such as methicillin and vancomycin target bacterial cell wall biosynthesis, but methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) have now arisen and are of major concern. Inhibitors acting on new targets in cell wall biosynthesis are thus of particular interest since they might also restore sensitivity to existing drugs, and the cis-prenyl transferase undecaprenyl diphosphate synthase (UPPS), essential for lipid I, lipid II, and thus, peptidoglycan biosynthesis, is one such target. We used 12 UPPS crystal structures to validate virtual screening models and then assayed 100 virtual hits (from 450,000 compounds) against UPPS from S. aureus and Escherichia coli. The most promising inhibitors (IC50 ∼2 μM, Ki ∼300 nM) had activity against MRSA, Listeria monocytogenes, Bacillus anthracis, and a vancomycin-resistant Enterococcus sp. with MIC or IC50 values in the 0.25-4 μg/mL range. Moreover, one compound (1), a rhodanine with close structural similarity to the commercial diabetes drug epalrestat, exhibited good activity as well as a fractional inhibitory concentration index (FICI) of 0.1 with methicillin against the community-acquired MRSA USA300 strain, indicating strong synergism. PMID:24827744

  18. Natural cholinesterase inhibitors from Myristica cinnamomea King.

    PubMed

    Abdul Wahab, Siti Mariam; Sivasothy, Yasodha; Liew, Sook Yee; Litaudon, Marc; Mohamad, Jamaludin; Awang, Khalijah

    2016-08-01

    A new acylphenol, malabaricone E (1) together with the known malabaricones A-C (2-4), maingayones A and B (5 and 6) and maingayic acid B (7) were isolated from the ethyl acetate extract of the fruits of Myristica cinnamomea King. Their structures were determined by 1D and 2D NMR techniques and LCMS-IT-TOF analysis. Compounds 3 (1.84±0.19 and 1.76±0.21μM, respectively) and 4 (1.94±0.27 and 2.80±0.49μM, respectively) were identified as dual inhibitors, with almost equal acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes inhibiting potentials. The Lineweaver-Burk plots of compounds 3 and 4 indicated that they were mixed-mode inhibitors. Based on the molecular docking studies, compounds 3 and 4 interacted with the peripheral anionic site (PAS), the catalytic triad and the oxyanion hole of the AChE. As for the BChE, while compound 3 interacted with the PAS, the catalytic triad and the oxyanion hole, compound 4 only interacted with the catalytic triad and the oxyanion hole. PMID:27236720

  19. Peptide deformylase inhibitors as potent antimycobacterial agents.

    PubMed

    Teo, Jeanette W P; Thayalan, Pamela; Beer, David; Yap, Amelia S L; Nanjundappa, Mahesh; Ngew, Xinyi; Duraiswamy, Jeyaraj; Liung, Sarah; Dartois, Veronique; Schreiber, Mark; Hasan, Samiul; Cynamon, Michael; Ryder, Neil S; Yang, Xia; Weidmann, Beat; Bracken, Kathryn; Dick, Thomas; Mukherjee, Kakoli

    2006-11-01

    Peptide deformylase (PDF) catalyzes the hydrolytic removal of the N-terminal formyl group from nascent proteins. This is an essential step in bacterial protein synthesis, making PDF an attractive target for antibacterial drug development. Essentiality of the def gene, encoding PDF from Mycobacterium tuberculosis, was demonstrated through genetic knockout experiments with Mycobacterium bovis BCG. PDF from M. tuberculosis strain H37Rv was cloned, expressed, and purified as an N-terminal histidine-tagged recombinant protein in Escherichia coli. A novel class of PDF inhibitors (PDF-I), the N-alkyl urea hydroxamic acids, were synthesized and evaluated for their activities against the M. tuberculosis PDF enzyme as well as their antimycobacterial effects. Several compounds from the new class had 50% inhibitory concentration (IC50) values of <100 nM. Some of the PDF-I displayed antibacterial activity against M. tuberculosis, including MDR strains with MIC90 values of <1 microM. Pharmacokinetic studies of potential leads showed that the compounds were orally bioavailable. Spontaneous resistance towards these inhibitors arose at a frequency of < or =5 x 10(-7) in M. bovis BCG. DNA sequence analysis of several spontaneous PDF-I-resistant mutants revealed that half of the mutants had acquired point mutations in their formyl methyltransferase gene (fmt), which formylated Met-tRNA. The results from this study validate M. tuberculosis PDF as a drug target and suggest that this class of compounds have the potential to be developed as novel antimycobacterial agents. PMID:16966397

  20. Corrosion inhibitor for aqueous ammonia absorption system

    DOEpatents

    Phillips, Benjamin A.; Whitlow, Eugene P.

    1998-09-22

    A method of inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425.degree. F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25.degree. C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425.degree. F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer.

  1. Replication and Inhibitors of Enteroviruses and Parechoviruses.

    PubMed

    van der Linden, Lonneke; Wolthers, Katja C; van Kuppeveld, Frank J M

    2015-08-01

    The Enterovirus (EV) and Parechovirus genera of the picornavirus family include many important human pathogens, including poliovirus, rhinovirus, EV-A71, EV-D68, and human parechoviruses (HPeV). They cause a wide variety of diseases, ranging from a simple common cold to life-threatening diseases such as encephalitis and myocarditis. At the moment, no antiviral therapy is available against these viruses and it is not feasible to develop vaccines against all EVs and HPeVs due to the great number of serotypes. Therefore, a lot of effort is being invested in the development of antiviral drugs. Both viral proteins and host proteins essential for virus replication can be used as targets for virus inhibitors. As such, a good understanding of the complex process of virus replication is pivotal in the design of antiviral strategies goes hand in hand with a good understanding of the complex process of virus replication. In this review, we will give an overview of the current state of knowledge of EV and HPeV replication and how this can be inhibited by small-molecule inhibitors. PMID:26266417

  2. Entry inhibitors: New advances in HCV treatment.

    PubMed

    Qian, Xi-Jing; Zhu, Yong-Zhe; Zhao, Ping; Qi, Zhong-Tian

    2016-01-01

    Hepatitis C virus (HCV) infection affects approximately 3% of the world's population and causes chronic liver diseases, including liver fibrosis, cirrhosis, and hepatocellular carcinoma. Although current antiviral therapy comprising direct-acting antivirals (DAAs) can achieve a quite satisfying sustained virological response (SVR) rate, it is still limited by viral resistance, long treatment duration, combined adverse reactions, and high costs. Moreover, the currently marketed antivirals fail to prevent graft reinfections in HCV patients who receive liver transplantations, probably due to the cell-to-cell transmission of the virus, which is also one of the main reasons behind treatment failure. HCV entry is a highly orchestrated process involving initial attachment and binding, post-binding interactions with host cell factors, internalization, and fusion between the virion and the host cell membrane. Together, these processes provide multiple novel and promising targets for antiviral therapy. Most entry inhibitors target host cell components with high genetic barriers and eliminate viral infection from the very beginning of the viral life cycle. In future, the addition of entry inhibitors to a combination of treatment regimens might optimize and widen the prevention and treatment of HCV infection. This review summarizes the molecular mechanisms and prospects of the current preclinical and clinical development of antiviral agents targeting HCV entry. PMID:26733381

  3. Identification and Validation of Novel PERK Inhibitors

    PubMed Central

    2015-01-01

    PERK, as one of the principle unfolded protein response signal transducers, is believed to be associated with many human diseases, such as cancer and type-II diabetes. There has been increasing effort to discover potent PERK inhibitors due to its potential therapeutic interest. In this study, a computer-based virtual screening approach is employed to discover novel PERK inhibitors, followed by experimental validation. Using a focused library, we show that a consensus approach, combining pharmacophore modeling and docking, can be more cost-effective than using either approach alone. It is also demonstrated that the conformational flexibility near the active site is an important consideration in structure-based docking and can be addressed by using molecular dynamics. The consensus approach has further been applied to screen the ZINC lead-like database, resulting in the identification of 10 active compounds, two of which show IC50 values that are less than 10 μM in a dose–response assay. PMID:24745945

  4. Polyphenol Compound as a Transcription Factor Inhibitor.

    PubMed

    Park, Seyeon

    2015-11-01

    A target-based approach has been used to develop novel drugs in many therapeutic fields. In the final stage of intracellular signaling, transcription factor-DNA interactions are central to most biological processes and therefore represent a large and important class of targets for human therapeutics. Thus, we focused on the idea that the disruption of protein dimers and cognate DNA complexes could impair the transcriptional activation and cell transformation regulated by these proteins. Historically, natural products have been regarded as providing the primary leading compounds capable of modulating protein-protein or protein-DNA interactions. Although their mechanism of action is not fully defined, polyphenols including flavonoids were found to act mostly as site-directed small molecule inhibitors on signaling. There are many reports in the literature of screening initiatives suggesting improved drugs that can modulate the transcription factor interactions responsible for disease. In this review, we focus on polyphenol compound inhibitors against dimeric forms of transcription factor components of intracellular signaling pathways (for instance, c-jun/c-fos (Activator Protein-1; AP-1), c-myc/max, Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and β-catenin/T cell factor (Tcf)). PMID:26529010

  5. Polyphenol Compound as a Transcription Factor Inhibitor

    PubMed Central

    Park, Seyeon

    2015-01-01

    A target-based approach has been used to develop novel drugs in many therapeutic fields. In the final stage of intracellular signaling, transcription factor–DNA interactions are central to most biological processes and therefore represent a large and important class of targets for human therapeutics. Thus, we focused on the idea that the disruption of protein dimers and cognate DNA complexes could impair the transcriptional activation and cell transformation regulated by these proteins. Historically, natural products have been regarded as providing the primary leading compounds capable of modulating protein–protein or protein-DNA interactions. Although their mechanism of action is not fully defined, polyphenols including flavonoids were found to act mostly as site-directed small molecule inhibitors on signaling. There are many reports in the literature of screening initiatives suggesting improved drugs that can modulate the transcription factor interactions responsible for disease. In this review, we focus on polyphenol compound inhibitors against dimeric forms of transcription factor components of intracellular signaling pathways (for instance, c-jun/c-fos (Activator Protein-1; AP-1), c-myc/max, Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and β-catenin/T cell factor (Tcf)). PMID:26529010

  6. Structure activity relationships of human galactokinase inhibitors.

    PubMed

    Liu, Li; Tang, Manshu; Walsh, Martin J; Brimacombe, Kyle R; Pragani, Rajan; Tanega, Cordelle; Rohde, Jason M; Baker, Heather L; Fernandez, Elizabeth; Blackman, Burchelle; Bougie, James M; Leister, William H; Auld, Douglas S; Shen, Min; Lai, Kent; Boxer, Matthew B

    2015-02-01

    Classic Galactosemia is a rare inborn error of metabolism that is caused by deficiency of galactose-1-phosphate uridyltransferase (GALT), an enzyme within the Leloir pathway that is responsible for the conversion of galactose-1-phosphate (gal-1-p) and UDP-glucose to glucose-1-phosphate and UDP-galactose. This deficiency results in elevated intracellular concentrations of its substrate, gal-1-p, and this increased concentration is believed to be the major pathogenic mechanism in Classic Galactosemia. Galactokinase (GALK) is an upstream enzyme of GALT in the Leloir pathway and is responsible for conversion of galactose and ATP to gal-1-p and ADP. Therefore, it was hypothesized that the identification of a small-molecule inhibitor of human GALK would act to prevent the accumulation of gal-1-p and offer a novel entry therapy for this disorder. Herein we describe a quantitative high-throughput screening campaign that identified a single chemotype that was optimized and validated as a GALK inhibitor. PMID:25553891

  7. Proton pump inhibitors decrease melanogenesis in melanocytes

    PubMed Central

    BAEK, SEUNG-HWA; LEE, SANG-HAN

    2015-01-01

    Proton pump inhibitors (PPIs) are widely used as inhibitors of gastric juice secretion for treatment of gastroesophageal reflux disease. However, there are no previous studies of the effects on melanogenesis resulting from PPI treatments. Therefore, the aim of the present study was to investigate the effects of PPIs on melanogenesis in melan-a cells derived from immortalized mouse melanocytes. Tyrosinase activity and copper-chelating activity were measured spectrophotometrically. In addition, the melanin content and viability of melan-a cells treated with PPIs were assessed and the mRNA levels of melanogenesis-associated genes were measured by reverse transcription-polymerase chain reaction. Treatment with rabeprazole, but not the other PPIs tested, resulted in strong, dose-dependent inhibition of mushroom tyrosinase (TYR). By contrast, each of the PPIs tested exhibited copper-chelating activity. Treatment of melan-a cells with 100 µM concentrations of the PPIs resulted in significantly reduced melanin synthesis and reduced expression of several melanogenesis-associated genes, including TYR, TYR-related protein-1 (TRP-1) and TRP-2, and microphthalmia-associated transcription factor, but did not result in cytotoxic effects. These results suggest that PPIs inhibit melanin biosynthesis in melan-a cells via the downregulation of melanogenesis-associated genes. Furthermore, the findings indicate that PPIs in general could be utilized as skin-whitening agents and/or as biomaterial for treating hyperpigmentation disorders. PMID:26405553

  8. Corrosion inhibitor for aqueous ammonia absorption system

    DOEpatents

    Phillips, B.A.; Whitlow, E.P.

    1998-09-22

    A method is described for inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425 F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25 C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425 F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer. 5 figs.

  9. Discovery of Biarylaminoquinazolines as Novel Tubulin Polymerization Inhibitors

    PubMed Central

    Ferrarese, Alessandro; Brun, Paola; Castagliuolo, Ignazio; Conconi, Maria Teresa; La Regina, Giuseppe; Bai, Ruoli; Silvestri, Romano; Hamel, Ernest; Chilin, Adriana

    2014-01-01

    Cell cycle experiments with our previously reported 4-biphenylaminoquinazoline (1–3) multityrosine kinase inhibitors revealed an activity profile resembling that of known tubulin polymerization inhibitors. Novel 4-biarylaminoquinazoline analogues of compound 2 were synthesized and evaluated as inhibitors of several tyrosine kinases and of tubulin. Although compounds 1–3 acted as dual inhibitors, the heterobiaryl analogues possessed only anti-tubulin properties and targeted the colchicine site. Furthermore, molecular modeling studies allowed the rationalization of the pharmacodynamic properties of the compounds. PMID:24801610

  10. Discovery of a selective irreversible BMX inhibitor for prostate cancer.

    PubMed

    Liu, Feiyang; Zhang, Xin; Weisberg, Ellen; Chen, Sen; Hur, Wooyoung; Wu, Hong; Zhao, Zheng; Wang, Wenchao; Mao, Mao; Cai, Changmeng; Simon, Nicholas I; Sanda, Takaomi; Wang, Jinhua; Look, A Thomas; Griffin, James D; Balk, Steven P; Liu, Qingsong; Gray, Nathanael S

    2013-07-19

    BMX is a member of the TEC family of nonreceptor tyrosine kinases. We have used structure-based drug design in conjunction with kinome profiling to develop a potent, selective, and irreversible BMX kinase inhibitor, BMX-IN-1, which covalently modifies Cys496. BMX-IN-1 inhibits the proliferation of Tel-BMX-transformed Ba/F3 cells at two digit nanomolar concentrations but requires single digit micromolar concentrations to inhibit the proliferation of prostate cancer cell lines. Using a combinatorial kinase inhibitor screening strategy, we discovered that the allosteric Akt inhibitor, MK2206, is able to potentiate BMX inhibitor's antiproliferation efficacy against prostate cancer cells. PMID:23594111

  11. Tumor necrosis factor inhibitors – state of knowledge

    PubMed Central

    Lis, Krzysztof; Kuzawińska, Olga

    2014-01-01

    Tumor necrosis factor (TNF) is considered a major proinflammatory cytokine, affecting various aspects of the immune reaction. All five TNF inhibitors currently available on the market (i.e., etanercept, infliximab, adalimumab, certolizumab and golimumab) are top sellers, although indicated only in autoimmune diseases, including rheumatoid arthritis, Crohn's disease and psoriasis. This article briefly discusses the background and place for TNF inhibitors in modern therapy. The main safety aspects of TNF inhibitor administration are described in particular, with special consideration of the available meta-analyses. Finally, perspectives on the next-generation TNF inhibitors and their use in the clinic are given. PMID:25624856

  12. Synthesis and In Vitro Evaluation of Aspartate Transcarbamoylase Inhibitors

    PubMed Central

    Coudray, Laëtitia; Pennebaker, Anne F.; Montchamp, Jean-Luc

    2009-01-01

    The design, synthesis, and evaluation of a series of novel inhibitors of aspartate transcarbamoylase (ATCase) are reported. Several submicromolar phosphorus-containing inhibitors are described, but all-carboxylate compounds are inactive. Compounds were synthesized to probe the postulated cyclic transition-state of the enzyme-catalyzed reaction. In addition, the associated role of the protonation state at the phosphorus acid moiety was evaluated using phosphinic and carboxylic acids. Although none of the synthesized inhibitors is more potent than N-phosphonacetyl-L-aspartate (PALA), the compounds provide useful mechanistic information, as well as the basis for the design of future inhibitors and/or prodrugs. PMID:19828320

  13. Squash inhibitors: from structural motifs to macrocyclic knottins.

    PubMed

    Chiche, Laurent; Heitz, Annie; Gelly, Jean-Christophe; Gracy, Jérôme; Chau, Pham T T; Ha, Phan T; Hernandez, Jean-François; Le-Nguyen, Dung

    2004-10-01

    In this article, we will first introduce the squash inhibitor, a well established family of highly potent canonical serine proteinase inhibitors isolated from Cucurbitaceae. The squash inhibitors were among the first discovered proteins with the typical knottin fold shared by numerous peptides extracted from plants, animals and fungi. Knottins contain three knotted disulfide bridges, two of them arranged as a Cystine-Stabilized Beta-sheet motif. In contrast to cyclotides for which no natural linear homolog is known, most squash inhibitors are linear. However, Momordica cochinchinensis Trypsin Inhibitor-I and (MCoTI-I and -II), 34-residue squash inhibitors isolated from seeds of a common Cucurbitaceae from Vietnam, were recently shown to be macrocyclic. In these circular squash inhibitors, a short peptide linker connects residues that correspond to the N- and C-termini in homologous linear squash inhibitors. In this review we present the isolation, characterization, chemical synthesis, and activity of these macrocyclic knottins. The solution structure of MCoTI-II will be compared with topologically similar cyclotides, homologous linear squash inhibitors and other knottins, and potential applications of such scaffolds will be discussed. PMID:15551519

  14. Inhibitory effects of respiration inhibitors on aflatoxin production.

    PubMed

    Sakuda, Shohei; Prabowo, Diyan Febri; Takagi, Keiko; Shiomi, Kazuro; Mori, Mihoko; Ōmura, Satoshi; Nagasawa, Hiromichi

    2014-04-01

    Aflatoxin production inhibitors, which do not inhibit the growth of aflatoxigenic fungi, may be used to control aflatoxin without incurring a rapid spread of resistant strains. A respiration inhibitor that inhibits aflatoxin production was identified during a screening process for natural, aflatoxin-production inhibitors. This prompted us to evaluate respiration inhibitors as potential aflatoxin control agents. The inhibitory activities of four natural inhibitors, seven synthetic miticides, and nine synthetic fungicides were evaluated on aflatoxin production in Aspergillus parasiticus. All of the natural inhibitors (rotenone, siccanin, aptenin A5, and antimycin A) inhibited fungal aflatoxin production with IC50 values around 10 µM. Among the synthetic miticides, pyridaben, fluacrypyrim, and tolfenpyrad exhibited strong inhibitory activities with IC50 values less than 0.2 µM, whereas cyflumetofen did not show significant inhibitory activity. Of the synthetic fungicides, boscalid, pyribencarb, azoxystrobin, pyraclostrobin, and kresoxim-methyl demonstrated strong inhibitory activities, with IC50 values less than 0.5 µM. Fungal growth was not significantly affected by any of the inhibitors tested at concentrations used. There was no correlation observed between the targets of respiration inhibitors (complexes I, II, and III) and their IC50 values for aflatoxin-production inhibitory activity. This study suggests that respiration inhibitors, including commonly used pesticides, are useful for aflatoxin control. PMID:24674936

  15. Inhibitory Effects of Respiration Inhibitors on Aflatoxin Production

    PubMed Central

    Sakuda, Shohei; Prabowo, Diyan Febri; Takagi, Keiko; Shiomi, Kazuro; Mori, Mihoko; Ōmura, Satoshi; Nagasawa, Hiromichi

    2014-01-01

    Aflatoxin production inhibitors, which do not inhibit the growth of aflatoxigenic fungi, may be used to control aflatoxin without incurring a rapid spread of resistant strains. A respiration inhibitor that inhibits aflatoxin production was identified during a screening process for natural, aflatoxin-production inhibitors. This prompted us to evaluate respiration inhibitors as potential aflatoxin control agents. The inhibitory activities of four natural inhibitors, seven synthetic miticides, and nine synthetic fungicides were evaluated on aflatoxin production in Aspergillus parasiticus. All of the natural inhibitors (rotenone, siccanin, aptenin A5, and antimycin A) inhibited fungal aflatoxin production with IC50 values around 10 µM. Among the synthetic miticides, pyridaben, fluacrypyrim, and tolfenpyrad exhibited strong inhibitory activities with IC50 values less than 0.2 µM, whereas cyflumetofen did not show significant inhibitory activity. Of the synthetic fungicides, boscalid, pyribencarb, azoxystrobin, pyraclostrobin, and kresoxim-methyl demonstrated strong inhibitory activities, with IC50 values less than 0.5 µM. Fungal growth was not significantly affected by any of the inhibitors tested at concentrations used. There was no correlation observed between the targets of respiration inhibitors (complexes I, II, and III) and their IC50 values for aflatoxin-production inhibitory activity. This study suggests that respiration inhibitors, including commonly used pesticides, are useful for aflatoxin control. PMID:24674936

  16. Solderability preservation through the use of organic inhibitors

    SciTech Connect

    Sorensen, N.R.; Hosking, F.M.

    1994-12-01

    Organic inhibitors can be used to prevent corrosion of metals and have application in the electronics industry as solderability preservatives. We have developed a model to describe the action of two inhibitors (benzotriazole and imidazole) during the environmental aging and soldering process. The inhibitors bond with the metal surface and form a barrier that prevents or retards oxidation. At soldering temperatures, the metal-organic complex breaks down leaving an oxide-free metal surface that allows excellent wetting by molten solder. The presence of the inhibitor retards the wetting rate relative to clean copper, but provides a vast improvement relative to oxidized copper.

  17. Molecular basis underlying resistance to Mps1/TTK inhibitors

    PubMed Central

    Koch, A; Maia, A; Janssen, A; Medema, R H

    2016-01-01

    Mps1/TTK is a dual-specificity kinase, with an essential role in mitotic checkpoint signaling, which has emerged as a potential target in cancer therapy. Several Mps1/TTK small-molecule inhibitors have been described that exhibit promising activity in cell culture and xenograft models. Here, we investigated whether cancer cells can develop resistance to these drugs. To this end, we treated various cancer cell lines with sublethal concentrations of a potent Mps1/TTK inhibitor in order to isolate inhibitor-resistant monoclonal cell lines. We identified four point mutations in the catalytic domain of Mps1/TTK that gave rise to inhibitor resistance but retained wild-type catalytic activity. Interestingly, cross-resistance of the identified mutations to other Mps1/TTK inhibitors is limited. Our studies predict that Mps1/TTK inhibitor-resistant tumor cells can arise through the acquisition of mutations in the adenosine triphosphate-binding pocket of the kinase that prevent stable binding of the inhibitors. In addition, our results suggest that combinations of inhibitors could be used to prevent acquisition of drug resistance. Interestingly, cross-resistance seems nonspecific for inhibitor scaffolds, a notion that can be exploited in future drug design to evict possible resistance mutations during clinical treatment. PMID:26364596

  18. Behaviour of tetramine inhibitors during pickling of hot rolled steels

    NASA Astrophysics Data System (ADS)

    Cornu, Marie-José; Koltsov, Alexey; Nicolas, Sabrina; Colom, Lydia; Dossot, Manuel

    2014-02-01

    To avoid the dissolution of steel in industrial pickling process, tetramine inhibitors are added to the pickling bath. This study is devoted to the understanding of the action mechanism of these inhibitors in hydrochloric and sulphuric baths on non-alloyed and alloyed steels. Pickling experiments and characterization with XPS, Raman and infrared spectroscopies have shown that inhibitors work only in acid media and leached out from the steel surfaces during the rinsing operation just after pickling. The effectiveness of inhibitors depends on the acid media and the temperature. Experimental data are consistent with a surface mechanism, i.e., the so-called "outer-sphere" adsorption.

  19. [Prospects for the design of new therapeutically significant protease inhibitors based on knottins and sunflower seed trypsin inhibitor (SFTI 1)].

    PubMed

    Kuznetsova, S S; Kolesanova, E F; Talanova, A V; Veselovsky, A V

    2016-05-01

    Plant seed knottins, mainly from the Cucurbitacea family, and sunflower seed trypsin inhibitor (SFTI 1) are the most low-molecular canonical peptide inhibitors of serine proteases. High efficiency of inhibition of various serine proteases, structure rigidity together with the possibility of limited variations of amino acid sequences, high chemical stability, lack of toxic properties, opportunity of production by either chemical synthesis or use of heterologous expression systems make these inhibitors attractive templates for design of new compounds for regulation of therapeutically significant serine protease activities. Hence the design of such compounds represents a prospective research field. The review considers structural characteristics of these inhibitors, their properties, methods of preparation and design of new analogs. Examples of successful employment of natural serine protease inhibitors belonging to knottin family and SFTI 1 as templates for the design of highly specific inhibitors of certain proteases are given. PMID:27562989

  20. CHZ868, a Type II JAK2 Inhibitor, Reverses Type I JAK Inhibitor Persistence and Demonstrates Efficacy in Myeloproliferative Neoplasms

    PubMed Central

    Meyer, Sara C.; Keller, Matthew D.; Chiu, Sophia; Koppikar, Priya; Guryanova, Olga A.; Rapaport, Franck; Xu, Ke; Manova, Katia; Pankov, Dmitry; O’Reilly, Richard J.; Kleppe, Maria; McKenney, Anna Sophia; Shih, Alan H.; Shank, Kaitlyn; Ahn, Jihae; Papalexi, Eftymia; Spitzer, Barbara; Socci, Nick; Viale, Agnes; Mandon, Emeline; Ebel, Nicolas; Andraos, Rita; Rubert, Joëlle; Dammassa, Ernesta; Romanet, Vincent; Dölemeyer, Arno; Zender, Michael; Heinlein, Melanie; Rampal, Rajit; Weinberg, Rona Singer; Hoffman, Ron; Sellers, William R.; Hofmann, Francesco; Murakami, Masato; Baffert, Fabienne; Gaul, Christoph; Radimerski, Thomas; Levine, Ross L.

    2015-01-01

    Summary Although clinically tested JAK inhibitors reduce splenomegaly and systemic symptoms, molecular responses are not observed in most myeloproliferative neoplasms (MPN) patients. We previously demonstrated that MPN cells become persistent to type I JAK inhibitors that bind the active conformation of JAK2. We investigated if CHZ868, a type II JAK inhibitor, would demonstrate activity in JAK inhibitor persistent cells, murine MPN models, and MPN patient samples. JAK2- and MPL-mutant cell lines were sensitive to CHZ868, including type I JAK inhibitor persistent cells. CHZ868 showed significant activity in murine MPN models and induced reductions in mutant allele burden not observed with type I JAK inhibitors. These data demonstrate that type II JAK inhibition is a viable therapeutic approach for MPN patients. PMID:26175413