Polimery w medycynie最新文献

Background: The adhesion of Pseudomonas aeruginosa to biotic and abiotic surfaces is responsible for the persistence and development of bacterial infection.

Objectives: To fill the gap in the knowledge regarding the relationship between rifaximin susceptibility and biofilm formation, and to investigate the effect of subinhibitory doses of rifaximin on the adhesion and biofilm formation.

Material and methods: A total of 10 isolates of P. aeruginosa were obtained from 110 urine samples of urinary tract infection (UTI) patients. Biofilm formation on polystyrene microtiter plates, minimum inhibitory concentrations (MICs) of rifaximin against the 10 isolates of P. aeruginosa (Pa1-Pa10), the effect of sub-MICs of rifaximin (0.5 × MIC, 0.25 × MIC, 0.125 × MIC, and 0.06 × MIC) on biofilm formation by the Pa4 isolate to polystyrene microtiter plates, and the adhesion to human epithelial cells (HECs) in vitro were evaluated.

Results: The MICs of rifaximin against 10 isolates ranged from 62.5 μg/mL to 1000 μg/mL. The Pa4 isolate produced the highest level of biofilm formation, while the MIC of Pa4 was 125 μg/mL. There was no correlation between bacterial susceptibility to rifaximin and biofilm formation (r: -0.016; p > 0.05). Sub-MIC doses of rifaximin significantly reduced the biofilm formation on abiotic surfaces, while only 0.5 × MIC, 0.25 × MIC and 0.12 × MIC of rifaximin reduced the adhesion to HECs significantly (p < 0.05) in a dose-dependent manner.

Conclusions: This pioneering study demonstrated the negative effect of sub-MIC doses of rifaximin on biofilm formation and adhesion to abiotic and biotic surfaces in vitro.

Tissue engineering has become one of the most studied medical fields and appears to be promising for the regeneration of injured bone tissues. Even though the bone has self-remodeling properties, bone regeneration may be required in some cases. Current research concerns materials employed to develop biological scaffolds with improved features as well as complex preparation techniques. Several attempts have been made to achieve compatible and osteoconductive materials with good mechanical strength in order to provide structural support. The application of biomaterials and mesenchymal stem cells (MSCs) is a promising prospect for bone regeneration. Recently, various cells have been utilized alone or in combination with biomaterials to accelerate bone repair in vivo. However, the question of what cell source is the best for use in bone engineering remains open. This review focuses on studies that evaluated bone regeneration using biomaterials with MSCs. Different types of biomaterials for scaffold processing, ranging from natural and synthetic polymers to hybrid composites, are presented. These constructs demonstrated an enhanced ability to regenerate the bone in vivo using animal models. Additionally, future perspectives in tissue engineering, such as the MSC secretome, that is the conditioned medium (CM), and the extracellular vesicles (EVs), are also described in this review. This new approach has already shown promising results for bone tissue regeneration in experimental models.

Background: Many substances are used to increase the viscosity of eye drops and reduce their surface tension. Their function is to prolong the persistence of the product on the surface of the eyeball and to increase the bioavailability of the pharmacologically active ingredient.

Objectives: To investigate the surface tension of substances added to the eye drops, with the main aim of modulating properties of the preparation.

Material and methods: Five substances contained in solutions proposed for the development of eye drops were studied: sodium hyaluronate macromolecular (H-Na W), sodium hyaluronate ultramolecular (H-Na UM), hyaluronic acid 4% (K-H), methylcellulose (MC), and polyacrylic acid (PA). The main method was to study the surface tension using the du Noüy ring tensiometer.

Results: The research presented in this paper shows the various effects of different eye drop ingredients on the surface tension of the solutions. The surface tension values of PA solutions are in the range of 48.89-56.03 mN/m, of MC in the range of 68.94-89.32 mN/m, of K-H 54.54-65.66 mN/m, of H-Na UM 67.18-70.97 mN/m, and of H-Na W 67.09-71.73 mN/m.

Conclusions: The use of different polymers affects the surface tension of model solutions proposed for use in ophthalmic preparations. Compounds containing carboxyl groups and anionic polymers have a similar effect on reducing the surface tension of the solution as classical surfactant compounds.

The introduction of tablet dosage forms has brought a revolution in the pharmaceutical drug delivery system. Different forms of tablets have been developed based on the target site, the onset of action, and therapeutic drug delivery methods. Fast-disintegrating tablets (FDTs) are the most promising pharmaceutical dosage form, especially for pediatric and geriatric patients having difficulty swallowing. The key feature of FDTs is quick drug release soon after their administration through the oral cavity. With innovations in the formulation of FDTs, the demand for excipients with better functionalities, particularly in terms of flow and compression characteristics, has increased. Co-processed excipients are a mixture of 2 or more conventional excipients that provides significant benefits over the individual excipients while minimizing their shortcomings. Such multifunctional co-processed excipients minimize the number of excipients that are to be incorporated into tablets during the manufacturing process. The present review discusses FTDs formulated from co-processed excipients, their manufacturing techniques, and the latest research, patents and commercially available co-processed FDTs.

In recent years, there has been a great interest in the potential use of contact lenses as eye drug delivery systems. Static (individual layers of the cornea, sclera and retina) as well as dynamic barriers (blood flow) pose a serious challenge to the effective delivery of the drug substance to the eyeball. The current ophthalmic systems are not optimal for patients, especially in the form of eye drops, where almost 95% of the drug contained in them is lost through the process of absorption through the conjunctiva or tear drainage. This article describes in vitro experiments that examined the use of contact lenses in the context of drug treatment in infectious, inflammatory, allergic, and glaucomatous diseases. Various techniques used to modify the materials as well as their impact on drug release kinetics were discussed. It has also been demonstrated that these methods can be used in practice during in vivo research, both in animal models as well as in sick and healthy people. The advantages of using controlled-release drug systems in the form of contact lenses are the drug dosing regimen, bioavailability and the prolonged residence time of drugs in the eyeball.

Background: Sida cordifolia and Sida rhombifolia are regarded as useful herbs as they have been shown to be effective, inexpensive and harmless in the prevention of diabetes, and are recognized as valuable therapeutic substances.

Objectives: The purpose of this study was to assess the effect of S. cordifolia and S. rhombifolia in the treatment of diabetic nephropathy using a rat model.

Material and methods: Extracts of S. cordifolia and S. rhombifolia were obtained using the Soxhlet method. The hydroalcoholic extract solvent was used in the following proportions: 70:30, 50:50 and 80:20. The 80:20 hydroalcoholic extract was observed to be the most potent. The inhibitory effects of the extract were determined using the α-amylase assay. The most potent extract also underwent total flavonoid, phenolic and free radical scavenging tests, and was incorporated into an animal study. Diabetes was induced in rats by administering nicotinamide (NAD; 230 mg/kg) and streptozotocin (STZ; 65 mg/kg) intraperitoneally. In addition to a standard control of pioglitazone, the rats received extract dosages of 100 mg/kg/day or 200 mg/kg/day. Body weight, blood glucose, glycated hemoglobin (HbA1c), blood urea nitrogen (BUN), serum albumin, serum creatinine, homeostatic model assessment of insulin resistance (HOMA-IR), and oral glucose tolerance were assessed at various time points. The animals also underwent histopathological examination to observe alterations induced by the treatment.

Results: Sida cordifolia was the most successful in lowering blood glucose and HbA1c levels. Renal function indices and antioxidant enzyme levels were regained in a dose-dependent manner. Furthermore, S. cordifolia (200 mg/kg/day) extract, similar to pioglitazone, inhibited the production of advanced glycation byproducts by the kidney.

Conclusions: The effects of various S. cordifolia and S. rhombifolia extracts on rats with diabetic nephropathy were observed. Sida cordifolia may be further explored for the treatment of diabetic nephropathy and, due to its diverse nature, may be utilized for the treatment of a wide range of diseases, as it provided more significant findings.

Background: Polymethylmethacrylate (PMMA) is the most used material for the manufacturing of eye prostheses.

Objectives: To investigate the cytotoxicity of different cleaning agents for ocular prostheses on human conjunctival cells.

Material and methods: Six groups of specimens were created (saline, soap, 4% chlorhexidine, hydrogen peroxide, 1% triclosan, and citronella oil). Three specimens were made for each disinfectant at each disinfection period (1, 7, 15, 30, 60, and 90 days), totaling 108 specimens. Thus, the specimens were disinfected, with different disinfectants, for different periods of time. After each disinfection process, the specimens were washed with sterile distilled water. A human conjunctival cell line was grown on the acrylic resin specimens and then cytotoxicity tests (MTT and Neutral Red (NR)) were performed. A negative control (untreated cell cultures) and positive control (Tween 20) were created. Two-way analysis of variance (ANOVA) and Bonferroni test were performed (p < 0.05).

Results: For the MTT and NR tests, when there was a significant difference between the disinfectant and negative control, the disinfectant generated a significant reduction in cell proliferation most of the time.

Conclusions: All reductions in cell proliferation caused by the disinfectants were clinically acceptable. All disinfectants tested in this study were found to be non-cytotoxic to human conjunctival cells.

Background: A basic parameter in non-equilibrium thermodynamics is the production of entropy (S-entropy), which is a consequence of the irreversible processes of mass, charge, energy, and momentum transport in various systems. The product of S-entropy production and absolute temperature (T) is called the dissipation function and is a measure of energy dissipation in non-equilibrium processes.

Objectives: This study aimed to estimate energy conversion in membrane transport processes of homogeneous non-electrolyte solutions. The stimulus version of the R, L, H, and P equations for the intensity of the entropy source achieved this purpose.

Material and methods: The transport parameters for aqueous glucose solutions through Nephrophan® and Ultra-Flo 145 dialyser® synthetic polymer biomembranes were experimentally determined. Kedem-Katchalsky-Peusner (KKP) formalism was used for binary solutions of non-electrolytes, with Peusner coefficients introduced.

Results: The R, L, H, and P versions of the equations for the S-energy dissipation were derived for the membrane systems based on the linear non-equilibrium Onsager and Peusner network thermodynamics. Using the equations for the S-energy and the energy conversion efficiency factor, equations for F-energy and U-energy were derived. The S-energy, F-energy and U-energy were calculated as functions of osmotic pressure difference using the equations obtained and presented as suitable graphs.

Conclusions: The R, L, H, and P versions of the equations describing the dissipation function had the form of second-degree equations. Meanwhile, the S-energy characteristics had the form of second-degree curves located in the 1st and 2nd quadrants of the coordinate system. These findings indicate that the R, L, H, and P versions of S-energy, F-energy and U-energy are not equivalent for the Nephrophan® and Ultra-Flo 145 dialyser® membranes.

Hepatocellular carcinoma (HCC) is the 7th most common cancer and the 3rd leading cause of cancer-related death worldwide. It is resistant to the majority of chemotherapeutics and has a dismal prognosis. Hepatocellular carcinoma is a prevalent complication of chronic liver disease (CLD) in India. Primary liver cancer is the 6th most common cancer worldwide and the 4th most prevalent cause of cancer-related death. In 2018, it affected 841,000 people and caused 782,000 deaths around the world. Thus, research into the tumor cycle and its prevention through suitable herbal (Unani/Ayurvedic) medication is critical for reducing the impact of primary liver cancer. Treatment options for end-stage liver cancer are limited, necessitating costly liver transplantation, which is unavailable in most countries. Here, we present the results of a comprehensive literature survey to determine the benefits of using various herbs with liver protective and antioxidant properties. This information will be useful to researchers working on liver carcinoma and free radical scavenging, both of which are important in curbing potential carcinogens.

Background: Occlusal splints can protect teeth during bruxism, preventing tooth wear, as well as during sports activities, shielding them from impacts.

Objectives: To verify the influence of thermal cycles and disinfection on the roughness, microhardness and color of polyethylene terephthalate glycol/thermoplastic polyurethane (PETG/TPU) and poly(methyl methacrylate) (PMMA).

Material and methods: Thirty-six PETG/TPU samples and 36 PMMA samples were prepared (ø10 mm × 3 mm). Six groups were created according to the material and the disinfection method used (n = 12 each): PETG/TPU (glister), PETG/TPU (hypochlorite), PETG/TPU (soap), PMMA (glister), PMMA (hypochlorite), and PMMA (soap). Roughness, Knoop microhardness and color evaluations were performed before the experiments (T1), after thermocycling (T2) and after disinfection (T3). Three-way repeated measures analysis of variance (ANOVA) and Tukey's test were used for statistical evaluations.

Results: For roughness and color, ANOVA showed statistical significance based on the interaction between thermal cycling, material and disinfectant factors. In terms of Knoop microhardness, ANOVA showed statistical significance based on the interaction between thermal cycling and material factors.

Conclusions: Roughness results were clinically acceptable in all groups at all time points, except the PETG/TPU and PMMA groups disinfected with hypochlorite. Microhardness significantly increased for both materials after thermal cycling, and at all time points, the microhardness of PMMA was significantly higher than that of PETG/TPU. After thermal cycling, the color changes were clinically unacceptable in all groups.