Polimery w medycynie最新文献

Background: Temporary prosthesis protects the oral tissues, in addition to providing aesthetic look and masticatory function until a definitive prosthesis is manufactured.

Objectives: To evaluate the effect of glaze and 0.12% chlorhexidine (CHX) on the physical and mechanical properties of bis-acryl, and to evaluate the antimicrobial efficacy of CHX.

Material and methods: Eighty specimens of bis-acryl resin were made. Over 40 of them the glaze was applied. One specimen with and 1 specimen without glaze were placed in niches of an appliance manufactured for each patient. Each of the 20 volunteers received 2 devices. Initially, the volunteers used one device and treated it with sucrose for 7 days (control), and later they used the other device and treated it with sucrose and CHX for 7 days (test). Color, microhardness, roughness, surface energy, and insoluble extracellular polysaccharides (EPS) tests were performed. All results were submitted to the Tukey's test, with the exception of the EPS results, which were submitted to the Student's t test.

Results: The ΔE00 of the unglazed control group was significantly higher than that of the unglazed test group. In all groups, a significant decrease in microhardness occurred over time. At both times, the glaze significantly increased the microhardness of the specimens (in all the glazed groups). At the final time, the test glaze group showed significantly higher microhardness compared with the control glaze group. Roughness in the groups without glaze increased significantly with CHX treatment over time. At both times, the glaze generated a significant reduction in roughness in the control and test groups. There was a significant reduction in surface energy over time in all groups. In most comparisons, the glazed groups showed significantly higher surface energy values compared with the unglazed control group. At the final time point, the unglazed test group showed a significantly higher surface energy value than the unglazed control group; and the glazed test group showed a significantly higher surface energy value compared with the glazed control group. The resins that received CHX had a significantly lower amount of biofilm.

Conclusions: Color values were clinically acceptable in all tested groups. At both time points, the roughness values were clinically acceptable only in the glazed groups. Glaze increased the microhardness of the specimens. Microhardness and surface energy were reduced over time in all groups. Chlorhexidine can help prevent microhardness degradation. Glaze and CHX can increase surface energy. Chlorhexidine reduced the amount of bacterial biofilm.

Background: The Textus Bioactiv Ag membrane is an active dressing for the treatment of chronic wounds such as venous stasis ulcers and burns.

Objectives: Determination of the transport and internal energy conversion properties of the Textus Bioactiv Ag membrane using the Kedem-Katchalsky-Peusner model. This model introduces the coefficients Lij necessary to calculate the degree of coupling (lij, QL), energy conversion efficiency (eij), dissipated energy (S-energy), free energy (F-energy), and internal energy (U-energy).

Material and methods: The research material was the Textus Bioactiv Ag membrane that is used as an active dressing in the treatment of difficult-to-heal wounds, and KCl aqueous solutions. The research methods employed Peusner's formalism of network thermodynamics and Kedem and Katchalsky's thermodynamics of membrane processes. To calculate the Lij coefficients, we used hydraulic conductivity (Lp), diffusion conductivity (ů) and reflection (ó) coefficients to perform experimental measurements in different conditions.

Results: The Lp coefficient for the Textus Bioactiv Ag membrane is nonlinearly dependent on the average concentrations of the solutions. In turn, the ů and ó coefficients are nonlinearly dependent on the differences in osmotic pressures (Äđ). An increase in the Äđ causes the Textus Bioactiv Ag membrane to become more permeable and less selective for KCl solutions. The coefficients of Peusner (Lij), couplings (lij, QL), energy conversion efficiency (eij), S-energy, F-energy, and U-energy also depend nonlinearly on Äđ. Our results showed that for higher concentrations of KCl solutions transported through the Textus Bioactiv Ag membrane, the coupling and energy conversion coefficients were greater for larger Äđ up to their maximum values for large Äđ. Coupling of the membrane structure with the electrolyte flux through the membrane is observed for Äđ greater than 10 kPa.

Conclusions: Textus Bioactiv Ag membrane dressings possess the properties of a solution component separator as well as an internal energy converter.

Background: Epithelial cells are the first barrier to any microbial invasion. Finding a safe and affordable substance to stimulate the innate immune response of epithelial cells is one of the main challenges immunologists and vaccine manufacturers are facing.

Objectives: This study aimed to show the comparative effect of sterile bacterial secretion (SBS) and Pseudomonas aeruginosa bacterial cell isolates obtained from burn wound infections on the ability of human epithelial cells (HECs) to produce interleukin (IL)-1β and tumor necrosis factor alpha (TNF-α) in vitro.

Material and methods: The HEC cultures were exposed to P. aeruginosa 8 (Pa 8), Pa 2 and Pa 1 bacterial cells (isolated from burn wound infections). The other 3 groups of HECs were exposed to 50 μL of sterile, endotoxin-free SBS of Pa 8, Pa 2 and Pa 1. The time course of changes in IL-1β mRNA, TNF-α mRNA, IL-1β, and TNF-α was examined.

Results: Moderate (p < 0.05) elevations of IL-1β mRNA in HECs and IL-1β protein in the supernatant of the HEC culture were observed following exposure to SBS of Pa 8, Pa 2 and Pa 1 at most time points. High elevation (p < 0.05) of IL-1β was seen in the supernatant of the HEC culture that was exposed to bacterial cells (Pa 8, Pa 2 and Pa 1). Similar results were found when TNF-α mRNA was measured in HECs and TNF-α in the supernatant of the HEC cultures after exposure to bacterial cells (Pa 8, Pa 2 and Pa 1) and the SBS of Pa 8, Pa 2 and Pa 1.

Conclusions: This is the first time that the capacity of SBS to generate epithelial cell pro-inflammatory cytokines in vitro has been shown. In other words, SBS enhanced a nonspecific immune response, which opens the door to the possibility of using SBS from P. aeruginosa as an adjuvant in the future.

Polymeric micelles and capsules are promising candidates for carriers of antineoplastic medications. Biodegradability and broadly defined biocompatibility are the key features that should always characterize polymers intended for medical applications. A well-designed delivery system ought to ensure the safe transport of chemotherapeutic agents to the target area and thus minimize systemic exposure to these drugs, limiting their toxic effect, preferably to the cancer cells. Polymeric micelles are often tailored for encapsulation of water-insoluble drugs. Micellar structures are usually fabricated as a result of self-assembly of various amphiphilic block copolymers in aqueous environment. More advanced methods are used to form capsules with a liquid core and a shell made of fused polymer nanoor microparticles. Such a coating can have homogeneous or heterogeneous composition. Janus and patchy capsules are usually characterized by more useful and advanced properties. Although some polymeric carriers are designed for a sustained release of the cargo, more sophisticated approaches involve payload liberation on demand under the influence of selected chemical or physical stimuli. The variety of available polymers and a wide range of possibilities of forming copolymers from different kind of monomers make polymeric materials ideal for the production of drug delivery systems with the desired properties. The aim of the present review is to sum up selected aspects of the use of polymeric micelles as carriers of cytostatic drugs, taking into account clinical applications. The additional objective is to show the studies on creating alternative systems based on stimuli-responsive capsules with shells made of polymeric particles.

Background: Burkholderia cepacia adhesion and biofilm formation onto abiotic surfaces is an important feature of clinically relevant isolates. The in vitro biofilm formation of B. cepacia onto coated indwelling urinary catheters (IDCs) with moxifloxacin has not been previously investigated.

Objectives: To examine the ability of B. cepacia to form biofilms on IDCs and the effect of coating IDCs with moxifloxacin on biofilm formation by B. cepacia in vitro.

Material and methods: The adhesion of B. cepacia to coated and uncoated IDCs with moxifloxacin was evaluated. Pieces of IDCs were coated with moxifloxacin (adsorption method). The spectrophotometric method was used to check moxifloxacin leaching into tubes. Coated and uncoated tubes were incubated with 107 colony forming units (cfu)/mL of B. cepacia. The viable bacterial count was used to count the number of bacteria adhered to coated and uncoated IDC pieces.

Results: A significant adhesion of B. cepacia to uncoated IDC pieces started 15 min after the incubation in a bacterial suspension (107 cfu/mL). A maximum adhesion was observed at 48 h. The pretreatment of IDCs with 100 μg/mL of moxifloxacin produced the best adsorption of antibiotic onto the IDCs. Coating IDC pieces with moxifloxacin significantly reduced the adhesion and biofilm formation of B. cepacia (p < 0.05) at various time intervals (1 h, 4 h and 24 h).

Conclusions: The present study has demonstrated for the first time that coated IDCs with moxifloxacin reduce B. cepacia adhesion and biofilm formation. This finding has opened the door to the production of the new generation IDCs that prevent bacteria from attaching and forming biofilms.

As the number of new drug candidates that are poorly soluble in water grows, new technologies that enable the enhancement of their solubility are needed. This is the case with amorphous solid dispersions (ASDs) that, nowadays, not only ensure the solubility, but can also be used to control the release rate of poorly soluble drugs. However, this dosage form must overcome the major disadvantage of ASDs, which is limited stability upon storage. Thus, a thorough knowledge on polymeric carriers that can enhance drug solubility while ensuring stability in the amorphous form is necessary. In this review, the state of the art in the application of Kollidon® VA 64 (copovidone) and Soluplus® (graft copolymer of polyvinyl caprolactam-polyvinyl acetate and poly(ethylene glycol) (PEG)) in the manufacturing of ASDs over the last 20 years is presented. Apart from the classical methods, namely solvent evaporation or melting, more advanced technologies such as pulse combustion drying, high-speed electrospinning and single-step 3D printing are described. It has been shown that both the dissolution rate (in vitro) and enhancement in bioavailability (in vivo) regarding poorly soluble active ingredients of natural or synthetic origin are possible using these matrix-forming polymers.

Background: Resin composites have various applications. At the same time, they have some drawbacks, such as polymerization shrinkage. Conventional composites are polymerized in 2-mm thick layers. However, in posterior restoration, the 2-mm depth of cure is not satisfactory. To find a solution, resin composites have been vastly improved in terms of fillers, matrix and initiators.

Objectives: To evaluate polymerization properties and physical characteristics of fiber-reinforced composites and compare them with bulk-fill composites that are designed for large posterior restorations.

Material and methods: Samples were prepared from each resin composite. The 3-point bending test was performed to evaluate the flexural strength of all composites. The depth of cure of the composite from 1 mm to 4 mm of depth was analyzed using Vickers hardness test (VHN). To analyze the degree of conversion, Fourier-transform infrared spectroscopy (FTIR) of the top and bottom surfaces of the samples with 4-mm thickness was calculated. The data were analyzed using one-way analysis of variance (ANOVA) test followed by post hoc test (95% confidence interval (95% CI)).

Results: The Filtek showed the highest flexural strength followed by everX and X-tra fil. At 1-mm depth, X-tra fil had the highest and Gradia had the lowest microhardness. At the 4-mm depth, the microhardness trend was as follows: everX > Filtek > X-tra fil > Gradia > Beautifil. The everX composite had the lowest reduction of the degree of conversion at 4-mm thickness, which showed a significant difference in comparison with Filtek, Gradia and X-tra fil composites.

Conclusions: Based on the results of our study, it can be concluded that the fiber-reinforced composite everX showed more favorable results regarding polymerization properties, such as the degree of conversion and the depth of cure. However, the flexural strength results in Filtek were better than those in everX.

Black pepper (Piper nigrum L.) is a climbing perennial plant in the Piperaceae family. Pepper has been known since antiquity for its use both as a medicine and a spice. It is particularly valued for its pungency attributed to its principal constituent - piperine. This review summarizes the information on the biological source of piperine, its extraction and isolation strategies, physicochemical properties, and pharmacological activity - analgesic, immunomodulatory, anti-depressive, anti-diarrheal, hepatoprotective, etc. The effect of piperine on biotransformation of co-administered drugs is also presented in this review, along with the mechanisms involved in its bioavailability-enhancing effect. Its important medicinal uses, including anti-hepatotoxic, anti-diarrheal, anti-depressive, analgesic, and immunomodulatory effects, besides many other traditional uses, are compiled. Based on an exhaustive review of literature, it may be concluded that piperine is a very promising alkaloid found in members of the Piperaceae family.

Background: Gamma-polyglutamic acid (γ-PGA) is a microbially produced non-toxic peptide biopolymer which is gaining grounds in many biotechnological fields and has a wide range of applications.

Objectives: In this study, the characteristics of γ-PGA produced by Bacillus megaterium isolated from an oil seed were determined, while the nutritional requirements of the bacterium were optimized using a predictive 15 factor-16 run Plackett-Burman experimental design.

Material and methods: The main effect of each factor, the interaction and quadratic effects of the factors on optimized production were determined from Box-Benkhen model using Dell Statistica v. 12 and 13 software. Bacillus megaterium UP47 produced the highest γ-PGA (16.33 g/L) out of 56 spore-forming Bacillus strains isolated from soil, water and fermented food samples.

Results: Hydrolysates of the produced γ-PGA had a retention factor which corresponded to the L-glutamic acid standard (retention factor (rf) 0.35), while high-definition fourier transform infrared (FT-IR) spectroscopic imaging showed characteristic peaks representative of the active bonds present in γ-PGA. The γ-PGA at a concentration as low as 50 mg/100 mL exerted antimicrobial inhibitions against test pathogens. A 2.00 w/v γ-PGA solution had 11 mm and 13 mm inhibition zones against Staphylococcus aureus and Shigella dysenteriae, respectively. A second order polynomial equation for prediction of γ-PGA was derived as: γPGA yield = 3316.061 - 449.708A + 9.036A2 - 139.813B + 3.095B2 - 7.699C - 0.164C2 + 13.116AB - 0.087AB2 - 0.248A2B + 3.781AC - 0.076A2C - 0.394BC. It showed an increase in γ-PGA yield with increasing L-glutamic acid and biotin, but a decrease with yeast extract.

Conclusions: Bacillus megaterium UP47 had a maximum γ-PGA yield of 54 g/L and 62 g/L, respectively, from the Plackett-Burman and Box-Benkhen design, thereby resulting in an appreciable increase in polymer yield after the optimization process with a 95% confidence level.

The history of "Polymers in Medicine" reflects not only the development of utilizing such materials in medicine and pharmaceutics, but also changes in Polish scientific journals - dissemination of results of scientific research and broader scientific activity always takes place in a specific linguistic and sociopolitical context. The paper presents a brief historical sketch of the journal, starting from the establishment of the information bulletin "Plastics in Medicine", through the 1st International Conference of the COMECON "Utilization of plastics in medicine", which took place in Warsaw in October 1969, and the founding of "Polymers in Medicine" in 1970-1971, until the present day. Subsequent editors-in-chief are introduced, along with transformations of the layout, and above all, the evolution of issues described in the published papers, which initially concerned chiefly polymer materials in general, orthotics and plastic medical equipment. The changing rhythm of publication of the journal is discussed on the background of economic transformations during the decline of Polish People's Republic and the early days of modern Poland. Languages in which articles and additional materials were published in "Polymers in Medicine" can be regarded as a symbol of changes in the globalizing world of science: between 1964 and 1986 four languages (Polish, English, Russian, and German), then three (without German) until 1997, then two (Russian also disappeared) and - since 2021 - one (English).