scholarly journals Anti-Adhesive Effect of Porous Polylactide Film in Rats

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 849
Author(s):  
Kyu Jin Chung ◽  
Youn Jung Kim ◽  
Tae Gon Kim ◽  
Jun Ho Lee ◽  
Yong-Ha Kim

Excessive adhesion between tissues on a significant area can cause the development of disorders, cosmetic problems, and ileus. Methods for preventing adhesion include the use of drugs and anti-adhesion barriers for physical blocking. In this study, the adhesion prevention effect of polylactide film in porous form was analyzed. A porous polylactide film was manufactured using a molecular weight of at least 100,000. To generate porosity, 98% methylene chloride and 95% ethyl alcohol were used as solvents. The thickness, surface, and internal pore shape of film were investigated. The crystal structures and melting temperature of film were measured. In the rat model, the presence and severity of adhesion were then analyzed. The thickness of the film ranged from 10 to 20 µm. The surface of the film contained pores with diameters of less than 10 µm. Partial crystallinity appeared from 15° to 20°, but the structure was amorphous overall. In the rat cecum abrasion model, adhesion occurred in 3 of the 13 rats in the polylactide experimental group, representing a 23.1% incidence rate. There were statistically significant differences in the severity of adhesion. The use of porous polylactide films can reduce the incidence of adhesion.


2017 ◽  
Vol 9 ◽  
pp. 117906521772090 ◽  
Author(s):  
Noppon Taksaudom ◽  
Metus Ketwong ◽  
Nirush Lertprasertsuke ◽  
Aphisek Kongkaew

Objective: The operating procedure of a resternotomy in open-heart surgery is a complicated procedure with potentially problematic outcomes partly due to potential adhesions in the pericardial cavity and retrosternal space. Use of a collagen membrane has shown encouraging results in adhesion prevention in several regions of the body. This study was designed to evaluate the effectiveness of the use of this collagen membrane in the prevention of pericardial adhesions. Materials and methods: A total of 12 pigs were divided randomly into 2 groups: an experimental group in which collagen membranes were used and a control group. After sternotomy and an anterior pericardiectomy, the epicardial surface was exposed to room air and irrigated with saline, and an epicardial abrasion was performed using a sponge. The pericardial defect was repaired using a collagen membrane in the experimental group or left uncovered in the control group. After 8 to 12 weeks, the pigs were killed, and a resternotomy was performed by a single-blinded surgeon enabling the evaluation of adhesions. The heart was then removed and sent for microscopic assessment conducted by a single-blinded pathologist. Results: The resternotomy operations performed using a collagen membrane demonstrated a nonstatistically significant trend of fewer macroscopic and microscopic adhesions in all regions ( P > .05), particularly in the retrosternal and defect regions. Conclusions: This study showed nonstatistically significant differences between the outcomes in the collagen membrane group and the control group in both macroscopic and microscopic adhesion prevention. Due to the many limitations in animal study design, further studies in human models will be needed before the true value of this procedure can be evaluated.



2019 ◽  
Vol 26 (4) ◽  
pp. 56-65
Author(s):  
М. M. Tlish ◽  
Е. К. Popandopulo

Aim. The paper studies the dynamics of the indicators defi ning the antioxidant system (AOS) and endogenous intoxication in patients with microbial eczema (ME) prior to and following treatment.Materials and methods. The experimental group consisted of patients with ME (n=30) and the control group comprising somatically healthy individuals (n=30). In this study, we determined the components of the antioxidant defence system in blood plasma and erythrocyte suspension, as well as assessed endogenous intoxication.Results. The study revealed an imbalance of indicators refl ecting the severity of oxidative stress and endogenous intoxication in patients suffering from ME. Prior to receiving treatment, the experimental group, as compared to the control group, exhibited an increase in catalase activity (CAT) up to 35.93 [32.50; 38.22] mmol / (min • l) (p < 0.001) and glutathione peroxidase (GPx) up to 1194.27 [1069.50; 1375.78] μmol / (min • l) (p < 0.001). In addition, there was a decrease in the activity of superoxide dismutase (SOD) to 13.28 [11.35; 14.10] u/l (p < 0.001), glutathione reductase (GR) to 501.46 [479.77; 542.52] mmol / (min • l) (p < 0.001) and the concentration of reduced glutathione to 1.64 [1.59; 1.78] μmol / ml (p = 0.043). We observed no statistically signifi cant changes in the total antioxidant activity (TAA) of blood plasma (0.59 [0.55;0.62] mg/l; р = 0.375) and the sulphhydryl groups (0.44 [0.41;0.47] ODU; р =0.111). The patients with ME exhibited the syndrome of endogenous intoxication (SEI), accompanied by an increase in the content of medium and low molecular weight molecules in plasma to 12.19 [11.20; 13.37] arb. u. (p < 0.001), with their content in erythrocytes being relatively normal – 15.23 [14.26; 16.44] arb. u. (p = 0.005). Following the treatment, changes in the studied parameters were of a multidirectional character in relation to the control values. An increased level of CAT and GPx (р <0,001), as well as lower values of SOD and GR, continued to be observed (р < 0.001). The TAA in serum (p = 0.308), sulphhydryl groups (p = 0.111) and reduced glutathione (p = 0.107) did not differ signifi cantly from the control values. The treatment did not reverse the SEI: the content of medium and low molecular weight molecules continued to increase in both plasma and erythrocytes, as compared to the control values (p < 0.001 in both cases).Conclusion. The obtained data confi rm the failure of mechanisms underlying antioxidant defence in patients with ME. Despite the attempt of its compensation by increasing the catalase activity, SOD control values were still not reached. An increase in the GPx activity along with a decrease in GR was observed, which could have lead, in turn, to a decrease in the concentration of reduced glutathione. The failure of the antioxidant defence mechanisms is also indicated by an increase in the content of medium and low molecular weight molecules, as well as by the development of the SEI, resulting from the excessive formation of reactive oxygen species and the inability of the antioxidant system to neutralise them.



2015 ◽  
Vol 815 ◽  
pp. 562-567
Author(s):  
Wang Fa Xu ◽  
Fa Meng Sun ◽  
Jing Bo Liu ◽  
Xiao Fang Li ◽  
Fa Ai Zhang

A series of porous poly(styrene-divinylbenzene) monoliths (polyHIPE) was synthesized by high internal phase emulsions (HIPE). The effects of the ethanol contents on the microstructure of the polyHIPE were characterized by scanning electron microscopy and mercury intrusion porosimeter. The adsorption and release behaviors of the polyHIPE for a monomer mixture consisting of dicyclopentadiene (DCPD) /styrene (St) (DS, mass ratio of 9/1) were investigated. The polymerization of the mixture DS within pores of the polyHIPE was studied. The results showed that the microstructure of the polyHIPE was significantly influenced by the ethanol content. The increase of ethanol in the HIPE increased the internal pore diameter and decreased the pore volume of the polyHIPE, thus decreased the DS absorption and increased the release rate. The DS monomer can enter the pores(cavities, windows) and fill the original holes after the polymerization. Compared with conventional polymerization of DCPD/St, the poly(DCPD/St) (pDS) obtained from confined spaces possess higher molecular weight, broader molecular weight distribution, and higher Tg. As the pore diameter increased, the effect of space confinement reduced, and the performances of pDS were closed to that prepared by conventional polymerization.



2008 ◽  
Vol 62 (6) ◽  
pp. 319-328 ◽  
Author(s):  
Ivana Cvetkovic ◽  
Jelena Milic ◽  
Mihail Ionescu ◽  
Zoran Petrovic

Vegetable oil-based and potentially biodegradable polyesters were prepared from 9-hydroxynonanoic acid methyl ester. This paper describes ozonolysis of vegetable oils and the method for preparation of useful monomers and in particular 9-hydroxynonanoic acid methyl ester. Ozonolysis of soybean oil and castor oil in methanol and methylene chloride solution, followed by reduction with sodium borohydride was used to obtain a mixture of triols, diols and monols. Triglyceride triols were separated from the rest of the mixture and transesterified with methanol to obtain methyl esters of fatty acids and glycerin. The main component of fatty acids was 9-hydroxynonanoic acid methyl ester, which was characterized and used for polycondensation by transesterification. High molecular weight polyhydroxy alcanoate was a solid having a melting point of 75?C. The molecular weight of the resulting polyester was affected by the purity of the monomer and side reactions such as cyclization. The polymer was characterized by chromatographic, thermal and analytical methods.



2009 ◽  
Vol 24 (6) ◽  
pp. 471-475 ◽  
Author(s):  
Ozdamar Fuad Oken ◽  
Ahmet Ozgur Yildirim ◽  
Murat Gulcek ◽  
Vuslat Sema Unal ◽  
Akin Karakuyu ◽  
...  

PURPOSE: To investigate the effect of prophylactic dose of a low molecular weight heparin, enoxaparin, on skin wound healing of rats. METHODS: Forty rats were used for the study. Rats were randomly assigned to two equal groups. Experimental group received prophylactic dose of enoxaparin. Physiologic saline was administered to the control group. Parameters of wound healing of experimental and control groups were compared. For comparison of the groups in terms of fibrosis, vascularization, inflammation, epithelization, and tensile strength test (Newton). Mann-Whitney-U test was used because variables were categorical data (fibrosis, vascularization, inflammation and epithelization). Differences between groups were analyzed with independent samples t-test (tensile strength). Significance was set at p<0.05. RESULTS: Skin wound of the experimental group presented tensile strength significantly decreased (p<0.001), histopathologic examination revealed a significant (p<0.001) delayed epithelization and decreased in fibrosis, vascularization, inflammation (p<0.001) in the experimental group. CONCLUSION: Enoxaparin delay wound healing by decreased inflammatory cells, fibroblast contents and their products (growth factors), and by promoted hemorrhage.



2018 ◽  
Vol 935 ◽  
pp. 27-30
Author(s):  
K.T. Shakhmurzova ◽  
Zh.I. Kurdanova ◽  
Arthur E. Baikaziev ◽  
Karina Kh. Teunova ◽  
Azamat A. Zhansitov ◽  
...  

The data on the methods for the preparation of polyetherketones by electrophilic and nucleophilic methods are considered and generalized. It is shown that polyetherketones by electrophilic substitution are carried out as homopolycondensation aromatic monocarboxylic acids and their halides and polycondensation of polynuclear aromatic hydrocarbons with aromatic dicarboxylic acids or their halides, and phosgene in organic solvents (1,2-dichloroethane, methylene chloride, nitrobenzene and etc.) in the presence of Ziegler-Natt catalysts. However, this process has not found an industrial application in view of such disadvantages as low yield of the desired product, the formation of a polymer with low molecular weight, synthesis time (15-40 hours), the use of large amounts of catalyst, the complexity of polymer purification of it.



1991 ◽  
Vol 69 (4) ◽  
pp. 702-705 ◽  
Author(s):  
G. W. Buchanan ◽  
J. K. Denike

The synthesis of 4′-vinylbenzo-12-crown-4 ether is reported. Polymerization to relatively low molecular weight polymers can be accomplished with a free radical initiator. A copolymer with styrene can be prepared and the Li+, Na+, and K+ binding properties of these polymers are compared to those of their monomeric analogs using salt distribution equilibria in water – methylene chloride. For all cations the homopolymer is found to extract the salts from the aqueous phase most effectively. The copolymer is slightly less effective than the homopolymer but more effective than either of the monomers by a factor of approximately 7, indicating that cooperative binding is likely. Na+ is the most efficiently extracted cation, followed by K+ and Li+. Key words: crown ether polymers, complexation properties.



2011 ◽  
Vol 695 ◽  
pp. 461-464
Author(s):  
Jing He ◽  
Xue Gang Luo ◽  
Tao Ying ◽  
Ji Liang Wu

In order to resolve the soil polluted problem which were brought by polyethylene, the study focus on the effects of different molecular weight polyethylene powders to soil, and discuss the molecular weight change of polyethylene. This study made use of four kinds of molecular weight polyethylene powders as materials, added them into the soil of potted soybean to test efficient N content, efficient P content, efficient K content in every development period of soybean, and test the molecular weight of four kinds of polyethylene after the whole development periods of soybean. The Important findings in this study were that there are no significant differences among the efficient N content, efficient P content, efficient K of control group and every experimental group, the molecular weight of polyethylene are nearly no change. it means that the different molecular weight polyethylene powders have no effect to soil.



1984 ◽  
Vol 39 (11-12) ◽  
pp. 1048-1051 ◽  
Author(s):  
Karl Eisele ◽  
Fernando Dias Costa ◽  
Carlos Pascual ◽  
Beatus Ofenloch-Hähnle

Abstract Affinity resins with different spacer arms were synthesized analogues to the solid phase peptide synthesis using aminoethyl cellulose or carboxymethyl cellulose as matrix. The spacer arms could be varied in length and rigidity. Especially spacer arms consisting of poly am ino acids can be synthesized with a defined amount of amino acid residues specifically in the low molecular weight ranges. The method is also applicable to other matrices w hich are not susceptible to 1 ɴ HCl in glacial acetic acid, trethylamine, methylene chloride and dimethylformamide. The synthesis of affinity resins with different spacer arms for the purification of androgen receptors is described as an example of the method.



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