scholarly journals Coagulotoxic Cobras: Clinical Implications of Strong Anticoagulant Actions of African Spitting Naja Venoms That Are Not Neutralised by Antivenom but Are by LY315920 (Varespladib)

Toxins ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 516 ◽  
Author(s):  
Mátyás A. Bittenbinder ◽  
Christina N. Zdenek ◽  
Bianca op den Brouw ◽  
Nicholas J. Youngman ◽  
James S. Dobson ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Area Under The Curve ◽  
Factor Xa ◽  
Well Being ◽  
Coagulation Cascade ◽  
Clotting Factor ◽  
Future Research ◽  
Thrombin Inhibition ◽  
Clinically Significant

Snakebite is a global tropical disease that has long had huge implications for human health and well-being. Despite its long-standing medical importance, it has been the most neglected of tropical diseases. Reflective of this is that many aspects of the pathology have been underinvestigated. Snakebite by species in the Elapidae family is typically characterised by neurotoxic effects that result in flaccid paralysis. Thus, while clinically significant disturbances to the coagulation cascade have been reported, the bulk of the research to date has focused upon neurotoxins. In order to fill the knowledge gap regarding the coagulotoxic effects of elapid snake venoms, we screened 30 African and Asian venoms across eight genera using in vitro anticoagulant assays to determine the relative inhibition of the coagulation function of thrombin and the inhibition of the formation of the prothrombinase complex through competitive binding to a nonenzymatic site on Factor Xa (FXa), thereby preventing FXa from binding to Factor Va (FVa). It was revealed that African spitting cobras were the only species that were potent inhibitors of either clotting factor, but with Factor Xa inhibited at 12 times the levels of thrombin inhibition. This is consistent with at least one death on record due to hemorrhage following African spitting cobra envenomation. To determine the efficacy of antivenom in neutralising the anticoagulant venom effects, for the African spitting cobras we repeated the same 8-point dilution series with the addition of antivenom and observed the shift in the area under the curve, which revealed that the antivenom performed extremely poorly against the coagulotoxic venom effects of all species. However, additional tests with the phospholipase A2 inhibitor LY315920 (trade name: varespladib) demonstrated a powerful neutralisation action against the coagulotoxic actions of the African spitting cobra venoms. Our research has important implications for the clinical treatment of cobra snakebites and also sheds light on the molecular mechanisms involved in coagulotoxicity within Naja. As the most coagulotoxic species are also those that produce characteristic extreme local tissue damage, future research should investigate potential synergistic actions between anticoagulant toxins and cytotoxins.

scholarly journals Inhibition of human coagulation factor VIII by monoclonal antibodies. Mapping of functional epitopes with the use of recombinant factor VIII fragments

1989 ◽  
Vol 263 (1) ◽  
pp. 187-194 ◽  
Author(s):  
A Leyte ◽  
K Mertens ◽  
B Distel ◽  
R F Evers ◽  
M J M De Keyzer-Nellen ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Factor Viii ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Procoagulant Activity ◽  
Coagulation Factor Viii ◽  
Coagulation Cascade ◽  
Restriction Enzyme Digestion ◽  
Proteolytic Activation

The epitopes of four monoclonal antibodies against coagulation Factor VIII were mapped with the use of recombinant DNA techniques. Full-length Factor VIII cDNA and parts thereof were inserted into the vector pSP64, permitting transcription in vitro with the use of a promoter specific for SP6 RNA polymerase. Factor VIII DNA inserts were truncated from their 3′-ends by selective restriction-enzyme digestion and used as templates for ‘run-off’ mRNA synthesis. Translation in vitro with rabbit reticulocyte lysate provided defined radiolabelled Factor VIII fragments for immunoprecipitation studies. Two antibodies are shown to be directed against epitopes on the 90 kDa chain of Factor VIII, between residues 712 and 741. The 80 kDa chain appeared to contain the epitopes of the other two antibodies, within the sequences 1649-1778 and 1779-1840 respectively. The effect of antibody binding to these sequences was evaluated at two distinct levels within the coagulation cascade. Both Factor VIII procoagulant activity and Factor VIII cofactor function in Factor Xa generation were neutralized upon binding to the region 1779-1840. The antibodies recognizing the region 713-740 or 1649-1778, though interfering with Factor VIII procoagulant activity, did not inhibit in Factor Xa generation. These findings demonstrate that antibodies that virtually inhibit Factor VIII in coagulation in vitro are not necessarily directed against epitopes involved in Factor VIII cofactor function. Inhibition of procoagulant activity rather than of cofactor function itself may be explained by interference in proteolytic activation of Factor VIII. This hypothesis is in agreement with the localization of the epitopes in the proximity of thrombin-cleavage or Factor Xa-cleavage sites.

scholarly journals Assessing COVID-19-related anxiety and functional impairment amongst nurses in Malawi

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Genesis Chorwe-Sungani
Keyword(s):  
Mental Health ◽  
Functional Impairment ◽  
Area Under The Curve ◽  
Reliability And Validity ◽  
Psychosocial Interventions ◽  
Well Being ◽  
Receiver Operating Curve ◽  
Future Research ◽  
Online Data ◽  
Cross Sectional

Background: Psychological well-being of nurses is crucial for them to effectively discharge their duties. However, coronavirus disease 2019 (COVID-19)-related anxiety can interfere with nurses’ performance and reduce their self-efficacy.Aim: The primary aim of this study was to assess COVID-19-related anxiety and functional impairment amongst nurses in Malawi. The secondary aim of the study was to determine reliability and validity of the Coronavirus Anxiety Scale.Setting: The study was conducted in Malawi.Methods: This was a cross-sectional study that collected quantitative data from 102 nurses in Malawi online. Data were analysed using descriptive statistics and receiver operating curve analysis.Results: This study found that 25.5% (26) of respondents had COVID-19-related anxiety and 48% (49) functional impairment. There were significant differences in the numbers of respondents who had functional impairment in relation to workplace (Χ2 = 8.7, p = 0.03), with many of those working in hospitals (58.6%, n = 34) having highest levels (mean = 20.6 ± 10.4). The Coronavirus Anxiety Scale proved to be an effective instrument (Sensitivity = 73.1%; Specificity = 60.5%; area under the curve = 0.73) for assessing COVID-19-related anxiety amongst nurses.Conclusion: It is necessary to screen nurses for COVID-19-related anxiety and functional impairment and provide them effective psychosocial interventions. Policymakers should place more emphasis on allocation of financial resources to mental health services and staff support programmes targeting nurses during pandemics. There is a need to conduct future research on mental health interventions that might be used to assist nurses with COVID-19-related anxiety and functional impairment.

scholarly journals Delphinidin and Its Glycosides’ War on Cancer: Preclinical Perspectives

2021 ◽  
Vol 22 (21) ◽  
pp. 11500
Author(s):  
Anshul Sharma ◽  
Hyo-Kyoung Choi ◽  
Yeon-Kye Kim ◽  
Hae-Jeung Lee
Keyword(s):  
Molecular Mechanisms ◽  
Future Research ◽  
Natural Health Products ◽  
Cell Protection ◽  
Anticancer Properties ◽  
Dietary Antioxidant ◽  
Health Products ◽  
Antioxidant Supplements

Until now, several studies have looked at the issue of anthocyanin and cancer, namely the preventive and inhibitory effects of anthocyanins, as well as the underlying molecular processes. However, no targeted review is available regarding the anticarcinogenic effects of delphinidin and its glycosides on various cancers and their plausible molecular mechanisms. Considerable evidence shows significant anticancer properties of delphinidin-rich preparations and delphinidin alone both in vitro and in vivo. This review covers the in vitro and preclinical implications of delphinidin-mediated cell protection and cancer prevention; thus, we strongly recommend that delphinidin-rich preparations be further investigated as potential functional food, dietary antioxidant supplements, and natural health products targeting specific chronic diseases, including cancer. In addition to in vitro investigations, future research should focus on more animal and human studies to determine the true potential of delphinidin.

scholarly journals Study on Structure Activity Relationship of Natural Flavonoids against Thrombin by Molecular Docking Virtual Screening Combined with Activity Evaluation In Vitro

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 422
Author(s):  
Xiaoyan Wang ◽  
Zhen Yang ◽  
Feifei Su ◽  
Jin Li ◽  
Evans Owusu Boadi ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Virtual Screening ◽  
Screening Method ◽  
Thrombin Inhibitors ◽  
Coagulation Cascade ◽  
Oh Groups ◽  
Structure Activity Relationships ◽  
Thrombin Inhibition ◽  
Structure Activity

Thrombin, a key enzyme of the serine protease superfamily, plays an integral role in the blood coagulation cascade and thrombotic diseases. In view of this, it is worthwhile to establish a method to screen thrombin inhibitors (such as natural flavonoid-type inhibitors) as well as investigate their structure activity relationships. Virtual screening using molecular docking technique was used to screen 103 flavonoids. Out of this number, 42 target compounds were selected, and their inhibitory effects on thrombin assayed by chromogenic substrate method. The results indicated that the carbon-carbon double bond group at the C2, C3 sites and the carbonyl group at the C4 sites of flavones were essential for thrombin inhibition, whereas the methoxy and O-glycosyl groups reduced thrombin inhibition. Noteworthy, introduction of OH groups at different positions on flavonoids either decreased or increased anti-thrombin potential. Myricetin exhibited the highest inhibitory potential against thrombin with an IC50 value of 56 μM. Purposively, the established molecular docking virtual screening method is not limited to exploring flavonoid structure activity relationships to anti-thrombin activity but also usefully discovering other natural active constituents.

In vitro effects of human neutrophil cathepsin G on thrombin generation: Both acceleration and decreased potential

2010 ◽  
Vol 104 (09) ◽  
pp. 514-522 ◽  
Author(s):  
Thomas Lecompte ◽  
Agnès Tournier ◽  
Lise Morlon ◽  
Monique Marchand-Arvier ◽  
Claude Vigneron ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Thrombin Generation ◽  
Time Course ◽  
Anticoagulant Activity ◽  
Cathepsin G ◽  
Coagulation Cascade ◽  
Clotting Factor ◽  
Factor V ◽  
Clotting Factors

SummaryCathepsin G (Cath G), a serine-protease found in neutrophils, has been reported to have effects that could either facilitate or impede coagulation. Thrombin generation (CAT method) was chosen to study its overall effect on the process, at a plasma concentration (240 nM) observed after neutrophil activation. Coagulation was triggered by tissue factor in the presence of platelets or phospholipid vesicles. To help identify potential targets of Cath G, plasma depleted of clotting factors or of inhibitors was used. Cath G induced a puzzling combination of two diverging effects of varying intensities depending on the phospholipid surface provided: accelerating the process under the three conditions (shortened clotting time by up to 30%), and impeding the process during the same thrombin generation time-course since thrombin peak and ETP (total thrombin potential) were decreased, up to 45% and 12%, respectively, suggestive of deficient prothrombinase. This is consistent with Cath G working on at least two targets in the coagulation cascade. Our data indicate that coagulation acceleration can be attributed neither to platelet activation and nor to activation of a clotting factor. When TFPI (tissue factor pathway inhibitor) was absent, no effect on lag time was observed and the anticoagulant activity of TFPI was decreased in the presence of Cath G. Consistent with the literature and the hypothesis of deficient prothrombinase, experiments using Russel’s Viper Venom indicate that the anticoagulant effect can be attributed to a deleterious effect on factor V. The clinical relevance of these findings deserves to be studied.

Food Derived Bioactive Peptides for Health Enhancement and Management of Some Chronic Diseases

2019 ◽  
pp. 1-11
Author(s):  
A. F. Ogori ◽  
A. T. Girgih ◽  
J. O. Abu ◽  
M. O. Eke
Keyword(s):  
Oxidative Stress ◽  
Chronic Diseases ◽  
Molecular Mechanisms ◽  
Bioactive Peptides ◽  
Food Sources ◽  
In Vivo Studies ◽  
Future Research ◽  
Target Cells

The bioactive peptides produced by enzymatic hydrolysis, acid hydrolysis and fermentation approach have been identified and used widely in research. These methods are important in enhancement or prevention and management of chronic diseases that are ravaging the world such as type -2-diabetes, hypertension, oxidative stress, cancer, and obesity. Sources of bioactive peptides have been established ranging from plant to animal and marine foods that have pharmacological effects; however these effects are dependent on target cells and peptides structure and conformations.  Plants such as hemp and animal source such as milk among others validate the findings of In vitro and In-vivo studies and the efficiency of these bioactive peptides in the management of certain chronic diseases. This article reviews the literature on bioactive peptides with concern on food sources, production and bioactive peptides application in enhancement of health and management of hypertension, diabetes and oxidative stress.  Future research efforts on bioactive peptides should be directed towards elucidating specific sequenced bioactive peptides and their molecular mechanisms, through In-vivo and In-vitro studies for specific health condition in human using nutrigenomics and peptideomic approaches.

scholarly journals Light quality affects the proliferation of in vitro cultured plantlets of Camellia oleifera Huajin

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10016
Author(s):  
Chaoyin He ◽  
Yanling Zeng ◽  
Yuzhong Fu ◽  
Jiahao Wu ◽  
Qin Liang
Keyword(s):  
Tissue Culture ◽  
Molecular Mechanisms ◽  
Light Quality ◽  
Southern China ◽  
Stomatal Density ◽  
Leaf Shape ◽  
Control Treatment ◽  
Future Research ◽  
Camellia Oleifera

Background Camellia oleifera is an important oil-yielding woody plant native to China. Tea oil extracted from the seeds is rich in health-beneficial compounds. Huajin is a high-yielding elite variety of C. oleifera, with large fruits and remarkable resilience, widely cultivated in southern China; however, its seedling quality tends to be uneven. At present, techniques such as grafting, and cuttings are primarily adopted to propagate C. oleifera. These approaches are susceptible to environmental constraints owing to the long growth period, resulting in the lack of C. oleifera seedlings. Methods to make the cultivation more economical are warranted; this can be facilitated by tissue culture technology to provide good-quality seedlings in a short time. Methods In vitro cultured plantlets of C. oleifera Huajin were exposed to red light (RL), blue light (BL), red:blue light at a 4:1 ratio (R4:B1), and red:blue light at a 1:4 ratio (R1:B4); white light (WL) was used as the control treatment. To investigate the influence of light spectral quality on the proliferation coefficient, photosynthetic pigments, soluble proteins, plant height, leaf shape, Rubisco enzyme activity, and stomata and leaf anatomical features. Results The highest proliferation coefficient was observed under combined red and blue (4:1) light. In addition, this treatment resulted in the second highest chlorophyll content, the thickest palisade and spongy tissues, and consequently, the thickest leaves. The same treatment resulted in the second highest stomatal density, albeit concomitantly with the smallest average stomatal length and width. Discussion These results indicate that high-quality propagation of Huajin shoots can be achieved by culturing the plants in vitro under a combination of red and blue (4:1) lights. Previous studies have shown that red and blue lights improve rooting and transplanting rates of tissue culture seedlings. Hence, future research should focus on the effect of light quality on rooting and transplanting of tissue culture plantlets of Huajin and its specific molecular mechanisms.

scholarly journals Food Derived Bioactive Peptides for Health Enhancement and Management of Some Chronic Diseases

2019 ◽  
pp. 1-11
Author(s):  
A. F. Ogori ◽  
A. T. Girgih ◽  
J. O. Abu ◽  
M. O. Eke
Keyword(s):  
Oxidative Stress ◽  
Chronic Diseases ◽  
Molecular Mechanisms ◽  
Bioactive Peptides ◽  
Food Sources ◽  
In Vivo Studies ◽  
Future Research ◽  
Target Cells

The bioactive peptides produced by enzymatic hydrolysis, acid hydrolysis and fermentation approach have been identified and used widely in research. These methods are important in enhancement or prevention and management of chronic diseases that are ravaging the world such as type -2-diabetes, hypertension, oxidative stress, cancer, and obesity. Sources of bioactive peptides have been established ranging from plant to animal and marine foods that have pharmacological effects; however these effects are dependent on target cells and peptides structure and conformations.  Plants such as hemp and animal source such as milk among others validate the findings of In vitro and In-vivo studies and the efficiency of these bioactive peptides in the management of certain chronic diseases. This article reviews the literature on bioactive peptides with concern on food sources, production and bioactive peptides application in enhancement of health and management of hypertension, diabetes and oxidative stress.  Future research efforts on bioactive peptides should be directed towards elucidating specific sequenced bioactive peptides and their molecular mechanisms, through In-vivo and In-vitro studies for specific health condition in human using nutrigenomics and peptideomic approaches.

scholarly journals Comparative Studies on the Anticoagulant Profile of Branded Enoxaparin and a New Biosimilar Version

2020 ◽  
Vol 26 ◽  
pp. 107602962096082
Author(s):  
Dalia Qneibi ◽  
Eduardo Ramacciotti ◽  
Ariane Scarlatelli Macedo ◽  
Roberto Augusto Caffaro ◽  
Leandro Barile Agati ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Thrombin Generation ◽  
Area Under The Curve ◽  
Factor Xa ◽  
In Vivo Studies ◽  
In Vitro Tests ◽  
Thrombin Time

Low molecular weight heparins (LMWH) represent depolymerized heparin prepared by various methods that exhibit differential, biochemical and pharmacological profiles. Enoxaparin is prepared by benzylation followed by alkaline depolymerization of porcine heparin. Upon the expiration of its patent, several biosimilar versions of enoxaparin have become available. Heparinox (Sodic enoxaparine; Cristália Produtos Químicos Farmacêuticos LTDA, Sao Paulo, Brazil) is a new biosimilar form of enoxaparin. We assessed the molecular weight and the biochemical profile of Heparinox and compared its properties to the original branded enoxaparin (Lovenox; Sanofi, Paris, France). Clotting profiles compared included activated clotting time, activated partial thromboplastin time (aPTT), and thrombin time (TT). Anti-protease assays included anti-factor Xa and anti-factor IIa activities. Thrombin generation was measured using a calibrated automated thrombogram and thrombokinetic profile included peak thrombin, lag time and area under the curve. USP potency was determined using commercially available assay kits. Molecular weight profiling was determined using high performance liquid chromatography. We determined that Heparinox and Lovenox were comparable in their molecular weight profile. Th anticoagulant profile of the branded and biosimilar version were also similar in the clot based aPTT and TT. Similarly, the anti-Xa and anti-IIa activities were comparable in the products. No differences were noted in the thrombin generation inhibitory profile of the branded and biosimilar versions of enoxaparin. Our studies suggest that Heparinox is bioequivalent to the original branded enoxaparin based upon in vitro tests however will require further in vivo studies in animal models and humans to determine their clinical bioequivalence.

Uncovering of Key Pathways and miRNAs for Intracranial Aneurysm Based on Weighted Gene Co-Expression Network Analysis

2022 ◽  
pp. 1-12
Author(s):  
Zhengfei Ma ◽  
Ping Zhong ◽  
Peidong Yue ◽  
Zhongwu Sun
Keyword(s):  
Network Analysis ◽  
Intracranial Aneurysm ◽  
Differentially Expressed Genes ◽  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Area Under The Curve ◽  
Enrichment Analysis ◽  
Functional Enrichment ◽  
Differentially Expressed

<b><i>Background:</i></b> Intracranial aneurysm (IA) is a serious cerebrovascular disease. The identification of key regulatory genes can provide research directions for early diagnosis and treatment of IA. <b><i>Methods:</i></b> Initially, the miRNA and mRNA data were downloaded from the Gene Expression Omnibus database. Subsequently, the limma package in R was used to screen for differentially expressed genes. In order to investigate the function of the differentially expressed genes, a functional enrichment analysis was performed. Moreover, weighted gene co-expression network analysis (WGCNA) was performed to identify the hub module and hub miRNAs. The correlations between miRNAs and mRNAs were assessed by constructing miRNA-mRNA regulatory networks. In addition, in vitro validation was performed. Finally, diagnostic analysis and electronic expression verification were performed on the GSE122897 dataset. <b><i>Results:</i></b> In the present study, 955 differentially expressed mRNAs (DEmRNAs, 480 with increased and 475 with decreased expression) and 46 differentially expressed miRNAs (DEmiRNAs, 36 with increased and 10 with decreased expression) were identified. WGCNA demonstrated that the yellow module was the hub module. Moreover, 16 hub miRNAs were identified. A total of 1,124 negatively regulated miRNA-mRNA relationship pairs were identified. Functional analysis demonstrated that DEmRNAs in the targeted network were enriched in vascular smooth muscle contraction and focal adhesion pathways. In addition, the area under the curve of 16 hub miRNAs was &#x3e;0.8. It is implied that 16 hub miRNAs may be used as potential diagnostic biomarkers of IA. <b><i>Conclusion:</i></b> Hub miRNAs and key signaling pathways were identified by bioinformatics analysis. This evidence lays the foundation for understanding the underlying molecular mechanisms of IA and provided potential therapeutic targets for the treatment of this disease.

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