scholarly journals A Study for the Access to a Semi-synthetic Regioisomer of Natural Fucosylated Chondroitin Sulfate with Fucosyl Branches on N-acetyl-Galactosamine Units

Marine Drugs ◽  
2019 ◽  
Vol 17 (12) ◽  
pp. 655 ◽  
Author(s):  
Giulia Vessella ◽  
Serena Traboni ◽  
Anna V. A. Pirozzi ◽  
Antonio Laezza ◽  
Alfonso Iadonisi ◽  
...  
Keyword(s):  
Chondroitin Sulfate ◽  
Anticoagulant Activity ◽  
The Body ◽  
New Drugs ◽  
Coagulation Cascade ◽  
Drug Candidate ◽  
Heterogeneous Structure ◽  
Anticoagulant Drug ◽  
Chemical Strategy

Fucosylated chondroitin sulfate (fCS) is a glycosaminoglycan found up to now exclusively in the body wall of sea cucumbers. It shows several interesting activities, with the anticoagulant and antithrombotic as the most attractive ones. Its different mechanism of action on the blood coagulation cascade with respect to heparin and the retention of its activity by oral administration make fCS a very promising anticoagulant drug candidate for heparin replacement. Nonetheless, its typically heterogeneous structure, the detection of some adverse effects and the preference for new drugs not sourced from animal tissues, explain how mandatory is to open an access to safer and less heterogeneous non-natural fCS species. Here we contribute to this aim by investigating a suitable chemical strategy to obtain a regioisomer of the natural fCS polysaccharide, with sulfated l-fucosyl branches placed at position O-6 of N-acetyl-d-galactosamine (GalNAc) units instead of O-3 of d-glucuronic acid (GlcA) ones, as in natural fCSs. This strategy is based on the structural modification of a microbial sourced chondroitin polysaccharide by regioselective insertion of fucosyl branches and sulfate groups on its polymeric structure. A preliminary in vitro evaluation of the anticoagulant activity of three of such semi-synthetic fCS analogues is also reported.

RESEARCH OF THE INFLUENCE OF ANTIBACTERIAL AND FUNGICIDAL PREPARATIONS ON FORMATION BIOFILM OF MICROORGANISMS

2021 ◽  
Vol 1 (4) ◽  
pp. 448-458
Author(s):  
Ekaterina M. Lenchenko ◽  
◽  
Dmitriy V. Stepanov ◽  
Dmitriy A. Blumenkrants ◽  
◽  
...  
Keyword(s):  
Culture Media ◽  
Animal Husbandry ◽  
The Body ◽  
Heterogeneous Structure ◽  
Candida Spp ◽  
Functional Patterns ◽  
Frequency Occurrence ◽  
Pathological Material

The results of studies general patterns formation heterogeneous structure biofilms gram-negative and gram-positive bacteria, as well as yeast-like fungi Candida spp. are presented. Рrocesses intercellular communication of various systematic groups microorganisms has common morphological and functional patterns biofilm formation. Heteromorphic structures of biofilms united by the intercellular matrix have been revealed in natural, industrial, and clinical conditions, both in the body of mammals and birds, and in food products, devices and equipment, animal husbandry and food production technologies. Indication in a large number of microcolonies, as well as yeast and micellar phases in isolates from pathological material of animals, was a differential sign in local and systemic pathologies. Under the influence drugs on biofilms microorganisms, a direct correlation was established between morphometric and densitometric indicators, reflecting a decrease in the frequency occurrence clusters and optical density, respectively. Under the bacteriostatic effect of chemotherapeutic and disinfecting drugs, accumulations altered cells of spheroplastic type, capable forming stable and unstable L-forms, were revealed. For detection of viable microorganisms in a heterogeneous population microorganisms in vitro and in vivo, fluorescence microscopy and culture media with growth factors for the repair cell wall of L-forms bacteria are promising.

scholarly journals THE RELATIONSHIP BETWEEN HEPARIN DOSAGE AND CLOTTING TIME

Blood ◽  
1948 ◽  
Vol 3 (10) ◽  
pp. 1197-1212 ◽  
Author(s):  
L. B. JAQUES ◽  
ANN G. RICKER
Keyword(s):  
Anticoagulant Activity ◽  
The Body ◽  
Time Response ◽  
Fixed Dose ◽  
Clotting Time ◽  
Anticoagulant Action ◽  
India Ink ◽  
The Relationship ◽  
Heparin Dosage

Abstract 1. The relationship between clotting time and heparin dosage has been studied in the dog. 2. On the addition of heparin to blood in vitro, a linear relation is found between heparin dosage and the logarithm of the clotting time obtained. The sensitivity of the blood sample to the action of added heparin is influenced both by the individual (coagulability of the blood before withdrawal) and by the technics of withdrawal and of determination of the clotting time. It is indicated that alterations in the latter may be used to extend the range of measurable hypocoagulability due to heparin. Incubation of heparin with blood for ten minutes increases its anticoagulant effect. 3. When moderate doses of heparin are injected intravenously, five to fifteen minutes are required for the clotting time to reach a maximum. No evidence of a biphasic response was obtained. The maximum clotting time obtained is greater than it is with the same amount of heparin added to the blood in vitro, due to the effect of incubation of heparin with blood on its anticoagulant activity. The in- terval required for the clotting time to return to normal is quite short, and with a given dosage is constant with different animals. Factors influencing the relation between duration of hypocoagulability and dosage are discussed. 4. A test has been devised to determine the sensitivity of the animal to the anticoagulant action of heparin. The clotting time response to certain concentrations of heparin added to the blood in vitro is determined. A fixed dose of heparin is then injected intravenously and the clotting time response is again determined. The response in vitro measures the sensitivity of the clotting system to heparin, while the in vivo response, when interpreted in the light of the in vitro response, measures the ability of the body to remove heparin from the circulation. 5. By means of this test, it has been determined that anesthesia with pentobarbital decreased the coagulability of the blood, urethane had no effect on coagulability, while the effect of ether was variable. The injection of india ink and evisceration caused a hypercoagulability, while removal of the kidneys had little effect. 6. When the sensitivity of the blood to the anticoagulant action of heparin was tested during these procedures, pentobarbital and nephrectomy had no effect, ether caused an increase in sensitivity, urethane a decrease. The injection of india ink and also evisceration markedly decreased the sensitivity of the blood to the anticoagulant action of heparin. 7. Anesthesia with pentobarbital, ether or urethane, the injection of india ink, removal of the kidneys, or removal of the gastrointestinal tract, had no effect on the duration of heparin action in the body.

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.

scholarly journals Efficacy of Spironolactone Treatment in Murine Models of Cutaneous and Visceral Leishmaniasis

2021 ◽  
Vol 12 ◽  
Author(s):  
Valter Viana Andrade-Neto ◽  
Juliana da Silva Pacheco ◽  
Job Domingos Inácio ◽  
Elmo Eduardo Almeida-Amaral ◽  
Eduardo Caio Torres-Santos ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Cutaneous Lesion ◽  
Parasite Burden ◽  
Parasite Load ◽  
New Drugs ◽  
Drug Candidate ◽  
Success Rates ◽  
Meglumine Antimoniate ◽  
Future Possibility

Translational studies involving the reuse and association of drugs are approaches that can result in higher success rates in the discovery and development of drugs for serious public health problems, including leishmaniasis. If we consider the number of pathogenic species in relation to therapeutic options, this arsenal is still small, and each drug possesses a disadvantage in terms of toxicity, efficacy, price, or treatment regimen. In the search for new drugs, we performed a drug screening of L. amazonensis promastigotes and intracellular amastigotes of fifty available drugs belonging to several classes according to their pharmacophoric group. Spironolactone, a potassium-sparing diuretic, proved to be the most promising drug candidate. After demonstrating the in vitro antileishmanial activity, we evaluated the efficacy on a murine experimental model with L. amazonensis and L. infantum. The treatment controlled the cutaneous lesion and reduced the parasite burden of L. amazonensis significantly, as effectively as meglumine antimoniate. The treatment of experimental visceral leishmaniasis was effective in reducing the parasite load on the main affected organs (spleen and liver) via high doses of spironolactone. The association between spironolactone and meglumine antimoniate promoted better control of the parasite load in the spleen and liver compared to the group treated with meglumine antimoniate alone. These results reveal a possible benefit of the concomitant use of spironolactone and meglumine antimoniate that should be studied more in depth for the future possibility of repositioning for leishmaniasis co-therapy.

scholarly journals Nanoencapsulation Enhances Anticoagulant Activity of Adenosine and Dipeptide IleTrp

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1191
Author(s):  
Trung Dinh Nguyen ◽  
The Ngoc Nguyen ◽  
Trang Thuy Thi Nguyen ◽  
Igor A. Ivanov ◽  
Khoa Cuu Nguyen ◽  
...  
Keyword(s):  
Biological Activity ◽  
Bleeding Time ◽  
Anticoagulant Activity ◽  
The Body ◽  
Clot Formation ◽  
Pluronic P123 ◽  
Transmission Electron ◽  
Clot Formation Time

It is well-known that drugs administered into an organism intravenously or through the gastrointestinal tract are degraded by enzymes of the body, reducing their therapeutic effect. One of the ways to decrease this undesirable process is through the inclusion of drugs in nanomaterials. Earlier strong anticoagulant activity was demonstrated for dipeptide IleTrp (IW) and adenosine (Ado). In this work, the effect of inclusion in nanomaterials on the biological activity of IW and Ado was studied. For this purpose, Ado and IW were incorporated into thermosensitive nanogel composed of pluronic P123-grafted heparin. The prepared nanocarrier was characterized by transmission electron microscopy, dynamic light scattering, and ζ-potential. Biological activity was determined by measuring the bleeding time from mouse tail in vivo and the time of clot formation in vitro. It was found that encapsulation of Ado and IW into nanomaterial significantly increased their effects, resulting in an increase in the bleeding time from mouse tail and clot formation time. Thus, inclusion of low molecular weight anticoagulants Ado and IW into nanomaterials may be considered a way to increase their biological activity.

Lung Based Engineered Micro-Pancreas Sustains Human Beta Cell Survival and Functionality

2019 ◽  
Vol 51 (12) ◽  
pp. 805-811
Author(s):  
Orit Goldman ◽  
Dmitry Puchinsky ◽  
Karina Durlacher ◽  
Rocio Sancho ◽  
Barbara Ludwig ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Cell Lines ◽  
Islet Cells ◽  
Human Islets ◽  
The Body ◽  
New Drugs ◽  
Metabolic Physiology ◽  
Insulin Secretion In Vitro ◽  
Clinical Potential

AbstractThe whole world has been affected by a dramatically increasing prevalence of diabetes. Today, the etiology of both type 1 and type 2 diabetes is thought to revolve around the dysfunction of β-cells, the insulin producing cells of the body. Within the pharmaceutical industry, the evaluation of new drugs for diabetes treatment is mostly done using cell lines or rodent islets and depends solely on the assessment of static insulin secretion. However, the use of cell lines or rodent islets is limiting lack of similarity of the human islet cells, leading to a constrain of the predictive value regarding the clinical potential of newly developed drugs. To overcome this issue, we developed an Engineered Micro-Pancreas as a unique platform for drug discovery. The Engineered Micro Pancreas is composed of (i) an organ-derived micro-scaffold, specifically a decellularized porcine lung-derived micro-scaffold and (ii) cadaveric islets seeded thereon. The Engineered Micro Pancreas remained viable and maintained insulin secretion in vitro for up to three months. The quantities of insulin were comparable to those secreted by freshly isolated human islets and therefore hold the potential for real-time and metabolic physiology mimicking drug screening.

scholarly journals Critical Considerations for the Design of Multi-Organ Microphysiological Systems (MPS)

2021 ◽  
Vol 9 ◽  
Author(s):  
Mridu Malik ◽  
Yang Yang ◽  
Parinaz Fathi ◽  
Gretchen J. Mahler ◽  
Mandy B. Esch
Keyword(s):  
Animal Models ◽  
Drug Toxicity ◽  
New Drugs ◽  
Drug Candidate ◽  
Preclinical Studies ◽  
Toxicity Screening ◽  
Drug Candidates ◽  
Microphysiological Systems

Identification and approval of new drugs for use in patients requires extensive preclinical studies and clinical trials. Preclinical studies rely on in vitro experiments and animal models of human diseases. The transferability of drug toxicity and efficacy estimates to humans from animal models is being called into question. Subsequent clinical studies often reveal lower than expected efficacy and higher drug toxicity in humans than that seen in animal models. Microphysiological systems (MPS), sometimes called organ or human-on-chip models, present a potential alternative to animal-based models used for drug toxicity screening. This review discusses multi-organ MPS that can be used to model diseases and test the efficacy and safety of drug candidates. The translation of an in vivo environment to an in vitro system requires physiologically relevant organ scaling, vascular dimensions, and appropriate flow rates. Even small changes in those parameters can alter the outcome of experiments conducted with MPS. With many MPS devices being developed, we have outlined some established standards for designing MPS devices and described techniques to validate the devices. A physiologically realistic mimic of the human body can help determine the dose response and toxicity effects of a new drug candidate with higher predictive power.

scholarly journals Predicting the In Vivo Performance of Cardiovascular Biomaterials: Current Approaches In Vitro Evaluation of Blood-Biomaterial Interactions

2021 ◽  
Vol 22 (21) ◽  
pp. 11390
Author(s):  
Anne Strohbach ◽  
Raila Busch
Keyword(s):  
Complement Activation ◽  
Clinical Success ◽  
In Vitro Models ◽  
The Body ◽  
Coagulation Cascade ◽  
Biological Processes ◽  
Testing Strategies ◽  
Cardiovascular Implants

The therapeutic efficacy of a cardiovascular device after implantation is highly dependent on the host-initiated complement and coagulation cascade. Both can eventually trigger thrombosis and inflammation. Therefore, understanding these initial responses of the body is of great importance for newly developed biomaterials. Subtle modulation of the associated biological processes could optimize clinical outcomes. However, our failure to produce truly blood compatible materials may reflect our inability to properly understand the mechanisms of thrombosis and inflammation associated with biomaterials. In vitro models mimicking these processes provide valuable insights into the mechanisms of biomaterial-induced complement activation and coagulation. Here, we review (i) the influence of biomaterials on complement and coagulation cascades, (ii) the significance of complement-coagulation interactions for the clinical success of cardiovascular implants, (iii) the modulation of complement activation by surface modifications, and (iv) in vitro testing strategies.

scholarly journals New Insights on Moojase, a Thrombin-Like Serine Protease from Bothrops moojeni Snake Venom

Toxins ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 500 ◽  
Author(s):  
Fernanda Amorim ◽  
Danilo Menaldo ◽  
Sante Carone ◽  
Thiago Silva ◽  
Marco Sartim ◽  
...  
Keyword(s):  
Snake Venom ◽  
Serine Proteases ◽  
New Drugs ◽  
Coagulation Cascade ◽  
Dependent Manner ◽  
Crude Venom ◽  
Human Fibrinogen ◽  
Factor Xia ◽  
Bothrops Moojeni

Snake venom serine proteases (SVSPs) are enzymes that are capable of interfering in various parts of the blood coagulation cascade, which makes them interesting candidates for the development of new therapeutic drugs. Herein, we isolated and characterized Moojase, a potent coagulant enzyme from Bothrops moojeni snake venom. The toxin was isolated from the crude venom using a two-step chromatographic procedure. Moojase is a glycoprotein with N-linked glycans, molecular mass of 30.3 kDa and acidic character (pI 5.80–6.88). Sequencing of Moojase indicated that it is an isoform of Batroxobin. Moojase was able to clot platelet-poor plasma and fibrinogen solutions in a dose-dependent manner, indicating thrombin-like properties. Moojase also rapidly induced the proteolysis of the Aα chains of human fibrinogen, followed by the degradation of the Bβ chains after extended periods of incubation, and these effects were inhibited by PMSF, SDS and DTT, but not by benzamidine or EDTA. RP-HPLC analysis of its fibrinogenolysis confirmed the main generation of fibrinopeptide A. Moojase also induced the fibrinolysis of fibrin clots formed in vitro, and the aggregation of washed platelets, as well as significant amidolytic activity on substrates for thrombin, plasma kallikrein, factor Xia, and factor XIIa. Furthermore, thermofluor analyses and the esterase activity of Moojase demonstrated its very high stability at different pH buffers and temperatures. Thus, studies such as this for Moojase should increase knowledge on SVSPs, allowing their bioprospection as valuable prototypes in the development of new drugs, or as biotechnological tools.

scholarly journals Antithrombotic Efficacy in the Guinea Pig of a Derivative of Human Protein C With Enhanced Activation by Thrombin

Blood ◽  
1997 ◽  
Vol 89 (2) ◽  
pp. 534-540 ◽  
Author(s):  
Ken D. Kurz ◽  
Tommy Smith ◽  
Alexander Wilson ◽  
Bruce Gerlitz ◽  
Mark A. Richardson ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Protein C ◽  
Thrombus Formation ◽  
Anticoagulant Activity ◽  
Activated Protein C ◽  
Human Protein ◽  
Coagulation Cascade ◽  
Activation Rate ◽  
Antithrombotic Efficacy

Abstract Conversion by α-thrombin of the zymogen human protein C (HPC) to activated protein C (aPC) is an important physiologic feedback control mechanism for the coagulation cascade. Although activation of HPC by thrombomodulin-bound thrombin is relatively rapid, activation by free thrombin occurs at a significantly slower rate. Previously, we generated a “hyper-activatable” derivative of HPC (FLIN-Q3) with an increased activation rate by free α-thrombin in vitro. In this study, the antithrombotic efficacy of FLIN-Q3 was compared with both native zymogen and aPC in an arteriovenous shunt model of thrombosis in the guinea pig. Recombinant proteins were infused 15 minutes before and throughout a 15-minute period while blood was circulated from carotid to jugular through tubing that enclosed a thread on which fibrin was deposited. Parallel dose-dependent antithrombotic responses were observed. Under these non–steady-state conditions, the calculated infusion doses associated with a 50% reduction of thrombus mass were 2.7, 24, and 250 mg/kg/h for aPC, FLIN-Q3, and HPC, respectively. Thrombus weight correlated inversely with plasma concentration of aPC, measured amidolytically, from either direct infusion of aPC or that generated from the zymogens in the animal, and similarly correlated inversely with anticoagulant activity measured by whole blood aPTT. Neither zymogen form showed significant aPC activity before shunt circulation, suggesting a requirement for exposure to thrombin. After the infusion was discontinued for 15 minutes, a second period of thrombus formation in the shunt demonstrated the ability of zymogen forms of PC, unlike aPC, to provide “on-demand” anticoagulant responses to repeated thrombotic stimuli. Thus, a “hyper-activatable” PC molecule such as FLIN-Q3 may represent a superior form of anticoagulant therapy than either the native zymogen or aPC.

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