scholarly journals Anti-Thrombin, Anti-Adhesive, Anti-Migratory, and Anti-Proliferative Activities of Sulfated Galactans from the Tropical Green Seaweed, Udotea flabellum

Marine Drugs ◽  
2018 ◽  
Vol 17 (1) ◽  
pp. 5 ◽  
Author(s):  
Maxsuell Mendes Marques ◽  
Fernando Presa ◽  
Rony Viana ◽  
Mariana Costa ◽  
Monica Amorim ◽  
...  
Keyword(s):  
Antitumor Agents ◽  
Anticoagulant Activity ◽  
Sulfated Polysaccharide ◽  
Northeastern Brazil ◽  
Sulfated Galactans ◽  
Green Seaweed ◽  
Coated Surface ◽  
Time Test ◽  
Coated Surfaces

In this study, sulfated polysaccharide-rich extracts were isolated from 22 tropical seaweeds (4 red, 11 brown, and 7 green) found in northeastern Brazil, and evaluated for the role of anticoagulant agents. Fifteen of the extracts showed anticoagulant activity, including all the extracts from green seaweeds. Udotea flabellum (a green seaweed) extract was the most potent, requiring an amount of only 3 µg to double the plasma coagulation time in the activated partial thromboplastin time test. A similar result was obtained with 1 µg of heparin. Two sulfated homogalactans with anticoagulant activity, F-I (130 kDa) and F-II (75 kDa), were isolated from this extract using several bio-guided purification steps. Their anticoagulant activity, as well as properties related to antitumor activity (anti-proliferative, anti-adhesive, and anti-migratory), were accessed. Their anticoagulant activities were close to that of heparin. We found that F-I and F-II (0.5–10 μg/mL) were not able to directly inhibit thrombin. In the presence of anti-thrombin, F-I (0.5 μg/mL) was more effective than heparin (0.5 μg/mL) in inhibiting thrombin, while F-II showed similar effects as heparin. F-I and F-II also inhibited B16-F10 (murine melanoma cells) adhesion, migration, and proliferation on a fibronectin-coated surface, but not on laminin- or collagen I-coated surfaces. Except for the antiproliferative activity, the other effects of F-I and F-II were eliminated upon their desulfation (~50%), indicating that the degree of sulfation is not as important for F-I and F-II anti-proliferative activity as the sulfation position. Taken together, the results provide strong evidence for the potential utility of sulfated galactans from U. flabellum, making these compounds an interesting option for future investigations that aim to design new anticoagulant/antitumor agents.

scholarly journals Anticoagulant activity of a sulfated polysaccharide isolated from the green seaweed Caulerpa cupressoides

2011 ◽  
Vol 54 (4) ◽  
pp. 691-700 ◽  
Author(s):  
José Ariévilo Gurgel Rodrigues ◽  
Edfranck de Sousa Oliveira Vanderlei ◽  
Érika Façanha Bessa ◽  
Francisco de Araújo Magalhães ◽  
Regina Célia Monteiro de Paula ◽  
...  
Keyword(s):  
Anticoagulant Activity ◽  
Sulfated Polysaccharide ◽  
Green Seaweed

Platelet Accumulation on Fibrin-coated Polyethylene: Role of Platelet Activation and Factor XIII

1995 ◽  
Vol 73 (05) ◽  
pp. 850-856 ◽  
Author(s):  
F D Rubens ◽  
D W Perry ◽  
M W C Hatton ◽  
P D Bishop ◽  
M A Packham ◽  
...  
Keyword(s):  
Factor Xiii ◽  
Cross Linking ◽  
Internal Diameter ◽  
Static System ◽  
Graft Occlusion ◽  
Platelet Binding ◽  
Coated Surface ◽  
Platelet Accumulation ◽  
Polyethylene Tubing

SummaryPlatelet accumulation on small- and medium-calibre vascular grafts plays a significant role in graft occlusion. We examined platelet accumulation on the surface of fibrin-coated polyethylene tubing (internal diameter 0.17 cm) during 10 min of flow (l0ml/min) at high wall shear rate (764 s-1). Washed platelets labelled with 51Cr were resuspended in Tyrode solution containing albumin, apyrase and red blood cells (hematocrit 40%). When the thrombin that was used to form the fibrin-coated surface was inactivated with FPRCH2C1 before perfusion of the tubes with the platelet:red blood cell suspension, the accumulation of platelets was 59,840 ± 27,960 platelets per mm2, whereas accumulation on fibrin with residual active thrombin was 316,750 ± 32,560 platelets per mm2 (n = 4). When the fibrin on the surface was cross-linked by including recombinant factor XIII (rFXIII) in the fibrinogen solution used to prepare the fibrin-coated surface, platelet accumulation, after thrombin neutralization, was reduced by the cross-linking from 46,974 ± 9702 to 36,818 ± 7964 platelets per mm2 (n = 12, p <0.01). Platelet accumulation on tubes coated with D-dimer was ten times less than on tubes coated with D-domain; this finding also supports the observation that cross-linking of fibrin with the formation of γ-γ dimers reduces platelet accumulation on the fibrin-coated surface. Thrombin-activated platelets themselves were shown to cross-link fibrin when they had adhered to it during perfusion, or in a static system in which thrombin was used to form clots from FXIII-free fibrinogen in the presence of platelets. Thus, cross-linking of fibrin by FXIII in plasma or from platelets probably decreases the reactivity of the fibrin-containing thrombi to platelets by altering the lysine residue at or near the platelet-binding site of each of the γ-chains of the fibrinogen which was converted into the fibrin of these thrombi.

Vitamin D as potential therapeutic anticancer agent

2018 ◽  
pp. 1-3
Keyword(s):  
Vitamin D ◽  
Anticancer Activity ◽  
Anticancer Agent ◽  
Antitumor Agents ◽  
Metastatic Potential ◽  
Anticancer Properties ◽  
Chemotherapy Agents

The role of vitamin D is implicated in carcinogenesis through numerous biological processes like induction of apoptosis, modulation of immune system inhibition of inflammation and cell proliferation and promotion of cell differentiation. Its use as additional adjuvant drug with cancer treatment may be novel combination for improved outcome of different cancers. Numerous preclinical, epidemiological and clinical studies support the role of vitamin D as an anticancer agent. Anticancer properties of vitamin D have been studied widely (both in vivo and in vitro) among various cancers and found to have promising results. There are considerable data that indicate synergistic potential of calcitriol and antitumor agents. Possible mechanisms for modulatory anticancer activity of vitamin D include its antiproliferative, prodifferentiating, and anti-angiogenic and apoptic properties. Calcitriol reduces invasiveness and metastatic potential of many cancer cells by inhibiting angiogenesis and regulating expression of the key molecules involved in invasion and metastasis. Anticancer activity of vitamin D is synergistic or additive with the antineoplastic actions of several drugs including cytotoxic chemotherapy agents like paclitaxel, docetaxel, platinum base compounds and mitoxantrone. Benefits of addition of vitamin D should be weighed against the risk of its toxicity.

Antioxidant and anticoagulant activity of sulfated polysaccharide from Gracilaria debilis (Forsskal)

2015 ◽  
Vol 81 ◽  
pp. 1031-1038 ◽  
Author(s):  
Sadhasivam Sudharsan ◽  
Namasivayam Subhapradha ◽  
Palaniappan Seedevi ◽  
Vairamani Shanmugam ◽  
Perumal Madeswaran ◽  
...  
Keyword(s):  
Anticoagulant Activity ◽  
Sulfated Polysaccharide

scholarly journals In vivo toxicological evaluation of crude sulfated polysaccharide from the green seaweed Caulerpa cupressoides var. lycopodium in Swiss mice - doi: 10.4025/actascitechnol.v35i4.15699

2013 ◽  
Vol 35 (4) ◽  
Author(s):  
José Ariévilo Gurgel Rodrigues ◽  
Edfranck De Sousa Oliveira Vanderlei ◽  
Ianna Wivianne Fernandes de Araújo ◽  
Ana Luíza Gomes Quinderé ◽  
Chistiane Oliveira Coura ◽  
...  
Keyword(s):  
Sulfated Polysaccharide ◽  
Toxicological Evaluation ◽  
Swiss Mice ◽  
Green Seaweed

S PROTEIN/VITRONECTIN NEUTRALIZES THE ANTICOAGULANT ACTIVITY OF GLYCOSAMINOGLYCANS IN THE INHIBITION OF THROMBIN BY HEPARIN COFACTOR II

1987 ◽  
Author(s):  
K T Preissner ◽  
P Sie
Keyword(s):  
Dermatan Sulfate ◽  
Enzyme Inhibitor ◽  
Anticoagulant Activity ◽  
Coagulation System ◽  
Binary Complex ◽  
Heparin Cofactor Ii ◽  
S Protein ◽  
Adhesive Protein ◽  
Inhibition Of Thrombin

The complement inhibitor S protein, which is identical to the adhesive protein vitronectin, functions as heparin-neutralizing factor by protecting thrombin against fast inactivation by antithrombin III. The interference of S protein with glycos-aminoglycan-catalyzed inhibition of thrombin by heparin cofactor II was investigated in a purified system. In the presence of 0.3 μg/ml heparin, or 0.5 μg/ml pentosan polyphosphate (SP 54), or 2 μg/ml dermatan sulfate, S protein induced a concentration-dependent reduction of the inhibition rate of thrombin by heparin cofactor II. This resulted in a decrease of the apparent pseudo-first order rate constants by about 17-fold (heparin), or about 7-fold (SP 54), but only by about 2-fold for dermatan sulfate at a physiological ratio of S protein to heparin cofactor II. Likewise, S protein significantly counteracted the anticoagulant activity of heparin and SP 54 bot not of dermatan sulfate when tested in an inhibition assay using various concentrations of glycosaminoglycans. For heparin, the activity of S protein at the point of 50% inhibition of thrombin was expressed in the range 0.06-0.6 μg/ml (0.01-0.1 U/ml) and for SP 54 in the range 0.3-2 pg/ml. Exposure of the glycos-aminoglycan-binding region of S protein by reduction and carb-oxymethylation of the protein even increased the neutralizing activity of S protein towards heparin and SP 54. S protein not only was found together with thrombin in a binary complex. S protein also became incorporated into a ternary complex with thrombin and heparin cofactor II as judged by crossed immunoelectrophoresis, regardless whether complex formation was initiated by heparin or dermatan sulfate. These findings underline the role of S protein as potent glycosaminoglycan-neutral-izing protein in plasma and as scavenger protein which may bind to enzyme-inhibitor complexes of the coagulation system.

scholarly journals Anticoagulant Properties of a Green Algal Rhamnan-type Sulfated Polysaccharide and Its Low-molecular-weight Fragments Prepared by Mild Acid Degradation

Marine Drugs ◽  
2018 ◽  
Vol 16 (11) ◽  
pp. 445 ◽  
Author(s):  
Xue Liu ◽  
Peng Du ◽  
Xiao Liu ◽  
Sujian Cao ◽  
Ling Qin ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Anticoagulant Activity ◽  
Sulfated Polysaccharide ◽  
Low Molecular Weight ◽  
Thrombin Time ◽  
Acid Degradation ◽  
Molecular Weights ◽  
Green Algal

The active sulfated polysaccharide from seaweed possesses important pharmaceutical and biomedical potential. In the study, Monostroma sulfated polysaccharide (MSP) was obtained from Monostroma angicava, and the low-molecular-weight fragments of MSP (MSP-Fs: MSP-F1–MSP-F6) were prepared by controlled acid degradation. The molecular weights of MSP and MSP-F1–MSP-F6 were 335 kDa, 240 kDa, 90 kDa, 40 kDa, 24 kDa, 12 kDa, and 6.8 kDa, respectively. The polysaccharides were sulfated rhamnans that consisted of →3)-α-l-Rhap-(1→ and →2)-α-l-Rhap-(1→ units with partial sulfation at C-2 of →3)-α-l-Rhap-(1→ and C-3 of →2)-α-l-Rhap-(1→. Anticoagulant properties in vitro of MSP and MSP-F1–MSP-F6 were evaluated by studying the activated partial thromboplastin time, thrombin time, and prothrombin time. Anticoagulant activities in vivo of MSP and MSP-F4 were further evaluated; their fibrin(ogen)olytic activities in vivo and thrombolytic properties in vitro were also assessed by D-dimer, fibrin degradation products, plasminogen activator inhibitior-1, and clot lytic rate assays. The results showed that MSP and MSP-F1–MSP-F4 with molecular weights of 24–240 kDa had strong anticoagulant activities. A decrease in the molecular weight of MSP-Fs was accompanied by a decrease in the anticoagulant activity, and higher anticoagulant activity requires a molecular weight of over 12 kDa. MSP and MSP-F4 possessed strong anticoagulant activities in vivo, as well as high fibrin(ogen)olytic and thrombolytic activities. MSP and MSP-F4 have potential as drug or helpful food supplements for human health.

Condensation of Low-Surface-Tension Fluids on Microstructured Surfaces at Low Temperature

2017 ◽  
Author(s):  
Abulimiti Aili ◽  
Qiaoyu Ge ◽  
TieJun Zhang
Keyword(s):  
Heat Transfer ◽  
Surface Tension ◽  
Low Temperature ◽  
High Surface ◽  
Condensation Heat Transfer ◽  
Lubricant Oil ◽  
Microstructured Surfaces ◽  
Performance Deterioration ◽  
Coated Surface ◽  
Coated Surfaces

Filmwise condensation of a low surface tension fluid (i.e. refrigerant) on microstructured aluminum surfaces is studied to investigate the effect of the structures on condensation heat transfer at low temperature. The hypothesis is that the structures may cause thinning of the condensate film at micro-scales, thus resulting in an enhancement of condensation heat transfer. However, the structures may also decrease the mobility of the condensate near the surface due to increased friction, thus potentially leading to performance deterioration. The aim of this work is to investigate which of the two counteracting mechanisms dominate during filmwise condensation. Condensation experiments are carried out in a low-temperature vacuum chamber. Compared with the Nusselt model of condensation, the microstructured surfaces, either coated or uncoated, show similar performance, with potentially slight enhancement at low subcooling degree and slight deterioration at high subcooling degree. When the microstructured and silane-coated surface is infused with a non-volatile and very low-surface-tension lubricant oil, the lubricant is displaced by the condensate and there is almost no change in the condensation performance. Our results show that, unlike the case of dropwise condensation of high-surface tension fluids, microstructured and coated surfaces with/without infusing oil is not exciting to enhanced filmwise condensation of low-surface-tension fluids.

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