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2.
Biomed Mater ; 19(4)2024 Jun 14.
Article in English | MEDLINE | ID: mdl-38838701

ABSTRACT

Although different fabrication methods and biomaterials are used in scaffold development, hydrogels and electrospun materials that provide the closest environment to the extracellular matrix have recently attracted considerable interest in tissue engineering applications. However, some of the limitations encountered in the application of these methods alone in scaffold fabrication have increased the tendency to use these methods together. In this study, a bilayer scaffold was developed using 3D-printed gelatin methacryloyl (GelMA) hydrogel containing ciprofloxacin (CIP) and electrospun polycaprolactone (PCL)-collagen (COL) patches. The bilayer scaffolds were characterized in terms of chemical, morphological, mechanical, swelling, and degradation properties; drug release, antibacterial properties, and cytocompatibility of the scaffolds were also studied. In conclusion, bilayer GelMA-CIP/PCL-COL scaffolds, which exhibit sufficient porosity, mechanical strength, and antibacterial properties and also support cell growth, are promising potential substitutes in tissue engineering applications.


Subject(s)
Anti-Bacterial Agents , Biocompatible Materials , Ciprofloxacin , Gelatin , Hydrogels , Materials Testing , Methacrylates , Polyesters , Printing, Three-Dimensional , Tissue Engineering , Tissue Scaffolds , Tissue Engineering/methods , Tissue Scaffolds/chemistry , Gelatin/chemistry , Ciprofloxacin/pharmacology , Ciprofloxacin/chemistry , Polyesters/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Biocompatible Materials/chemistry , Hydrogels/chemistry , Porosity , Methacrylates/chemistry , Collagen/chemistry , Animals , Humans , Cell Proliferation/drug effects
3.
Nanomaterials (Basel) ; 14(7)2024 Mar 23.
Article in English | MEDLINE | ID: mdl-38607098

ABSTRACT

Tympanic membrane (TM) perforations, primarily induced by middle ear infections, the introduction of foreign objects into the ear, and acoustic trauma, lead to hearing abnormalities and ear infections. We describe the design and fabrication of a novel composite patch containing photocrosslinkable gelatin methacryloyl (GelMA) and keratin methacryloyl (KerMA) hydrogels. GelMA-KerMA patches containing conical microneedles in their design were developed using the digital light processing (DLP) 3D printing approach. Following this, the patches were biofunctionalized by applying a coaxial coating with PVA nanoparticles loaded with gentamicin (GEN) and fibroblast growth factor (FGF-2) with the Electrohydrodynamic Atomization (EHDA) method. The developed nanoparticle-coated 3D-printed patches were evaluated in terms of their chemical, morphological, mechanical, swelling, and degradation behavior. In addition, the GEN and FGF-2 release profiles, antimicrobial properties, and biocompatibility of the patches were examined in vitro. The morphological assessment verified the successful fabrication and nanoparticle coating of the 3D-printed GelMA-KerMA patches. The outcomes of antibacterial tests demonstrated that GEN@PVA/GelMA-KerMA patches exhibited substantial antibacterial efficacy against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Furthermore, cell culture studies revealed that GelMA-KerMA patches were biocompatible with human adipose-derived mesenchymal stem cells (hADMSC) and supported cell attachment and proliferation without any cytotoxicity. These findings indicated that biofunctional 3D-printed GelMA-KerMA patches have the potential to be a promising therapeutic approach for addressing TM perforations.

4.
Dalton Trans ; 53(15): 6709-6719, 2024 Apr 16.
Article in English | MEDLINE | ID: mdl-38530270

ABSTRACT

Herein, we apply three different copper-exchanged materials (Na-[Al]SBA-15, silica, Na-MCM-22) as hosts for a direct synthesis of CuI(1,1'-bis(diphenylphosphino)ferrocene = dppf) complexes in cationic ion exchange position. Using 31P MAS NMR spectroscopy, we show that identical complexes as after ion exchange are generated if the solids are applied as reactants directly. The homogeneity of copper exchanges is evaluated by EDX spectroscopy. Both CuI and CuII result in the formation of complexes, thereby oxidizing dppf. Cu-particles were not reactive. Optimized conditions for a maximized complex formation are identified applying quantitative 31P MAS NMR spectroscopy and ICP-OES. Only accessible copper in cationic position of the solids forms the complexes. This enables a quantification of the amount of copper in mesopores vs. the total copper amount. Thus, besides a new synthesis of the complex a suitable method for quantitative elucidation of the location of copper cations is demonstrated herein.

5.
ACS Omega ; 9(6): 6442-6454, 2024 Feb 13.
Article in English | MEDLINE | ID: mdl-38371772

ABSTRACT

Nowadays, with the evolution of technology, rare earths are raw materials for a multitude of products, especially in high technological applications. A high amount of REEs is used in the production of permanent magnets, particularly NdFeB. The demand for some of the REEs, including neodymium, praseodymium, and dysprosium, is expected to increase in the coming years. REEs are defined as critical materials due to their high supply risk and economic importance. Recycling secondary raw materials for supplying REEs in the future is one promising option, and one of the best candidates is NdFeB magnets. NdFeB magnets include approximately 30% REEs and 66% of iron. For the near-zero-waste concept, the recovered iron from NdFeB must be evaluated in other applications. In this study, the near-zero-waste valorization concept for EoL-NdFeB magnets is developed, and high-purity REEs are achieved with a two-step process, including leaching and adsorption using alginate beads. Moreover, antimicrobial Fe alginate beads are produced in the leach liquor via adsorption. The antimicrobial activity of the produced Fe alginate beads is evaluated with disc diffusion and broth dilution methods against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The most effective antibacterial Fe alginate beads are against E. coli and S. aureus with inhibitions of 87.21 and 56.25%, respectively.

6.
Molecules ; 28(24)2023 Dec 12.
Article in English | MEDLINE | ID: mdl-38138536

ABSTRACT

Crystal size is a key parameter of zeolites applied as catalysts. Herein, ZSM-5 crystals with similar physicochemical and acid properties, few defects, and aluminum exclusively in tetrahedral coordination are synthesized and the influence of the crystal size on the MTO and ETA conversion is investigated. Short olefins are the main products of the MTO conversion, whereas larger olefins and aromatics dominate the products after ETA conversion. In the case of both feeds, an increased crystal size decreases the catalyst's lifetime. The MTO conversion over larger ZSM-5 altered the product distribution, which was not the case for the ETA conversion. The reason is that the instantly available aromatics during ETA conversion lead to fast coking and zeolite crystals only active in the outer layers. Thus, the different reactivity of different-sized ZSM-5 is direct proof of a different conversion mechanism for both alcohols.

7.
ACS Omega ; 8(31): 28109-28121, 2023 Aug 08.
Article in English | MEDLINE | ID: mdl-37576652

ABSTRACT

In this study, two-layer poly(vinyl alcohol)/gelatin (PVA/GEL) nanofiber patches containing cinnamaldehyde (CA) in the first layer and gentamicin (GEN) in the second layer were produced by the electrospinning method. The morphology, chemical structures, and thermal temperatures of the produced pure (PVA/GEL), CA-loaded (PVA/GEL/CA), GEN-loaded (PVA/GEL/GEN), and combined drug-loaded (PVA/GEL/CA/GEN) nanofiber patches were determined by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and differential scanning calorimetry, respectively. Their mechanical properties, swelling and degradation behavior, and drug release kinetics were investigated. SEM images showed that both drug-free and drug-loaded nanofiber patches possess smooth and monodisperse structures, and nanofiber size increase occurred as the amount of drug increased. The tensile test results showed that the mechanical strength decreased as the drug was loaded. According to the drug release results, CA release ended at the 96th hour, while GEN release continued until the 264th hour. The antibacterial and antibiofilm activities of PVA/GEL, PVA/GEL/CA, PVA/GEL/GEN, and PVA/GEL/CA/GEN nanofiber patches against Pseudomonas aeruginosa and Staphylococcus aureus were evaluated. Results showed that PVA/GEL/GEN and PVA/GEL/CA/GEN nanofiber patches have excellent antibacterial and antibiofilm activities. Moreover, all materials were biocompatible, with no cytotoxic effects in the mammalian cell model for 8 days. PVA/GEL/GEN nanofiber patches were the most promising material for a high cell survival ratio, which was confirmed by SEM images. This research aims to develop an alternative method to stop and treat the rapid progression of bacterial keratitis.

8.
Childs Nerv Syst ; 39(11): 3207-3214, 2023 11.
Article in English | MEDLINE | ID: mdl-37480521

ABSTRACT

PURPOSE: The aim of this study was to determine the clinical, laboratory, and radiological factors related with posttraumatic epilepsy (PTE). METHODS: The study is a multicenter descriptive cross-sectional cohort study. Children who followed up for TBI in the pediatric intensive care unit between 2014 and 2021 were included. Demographic data and clinical and radiological parameters were recorded from electronic case forms. All patients who were in the 6-month posttraumatic period were evaluated by a neurologist for PTE. RESULTS: Four hundred seventy-seven patients were included. The median age at the time of trauma was 66 (IQR 27-122) months, and 298 (62.5%) were male. Two hundred eighty (58.7%) patients had multiple traumas. The mortality rate was 11.7%. The mean duration of hospitalization, pediatric intensive care unit hospitalization and mechanical ventilation, Rotterdam score, PRISM III score, and GCS at admission were higher in patients with epilepsy (p < 0.05). The rate of epilepsy was higher in patients with severe TBI, cerebral edema on tomography and clinical findings of increased intracranial pressure, blood transfusion in the intensive care unit, multiple intracranial hemorrhages, and intubated patients (p < 0.05). In logistic regression analysis, the presence of intracranial hemorrhage in more than one compartment of the brain (OR 6.13, 95%CI 3.05-12.33) and the presence of seizures (OR 9.75, 95%CI 4.80-19.83) were independently significant in terms of the development of epilepsy (p < 0.001). CONCLUSIONS: In this multicenter cross-sectional study, intracranial hemorrhages in more than one compartment and clinical seizures during intensive care unit admission were found to be independent risk factors for PTE development in pediatric intensive care unit patients with TBI.


Subject(s)
Brain Injuries, Traumatic , Critical Illness , Child , Female , Humans , Male , Brain Injuries, Traumatic/complications , Brain Injuries, Traumatic/diagnostic imaging , Cross-Sectional Studies , Intracranial Hemorrhages , Seizures , Child, Preschool
9.
Molecules ; 28(13)2023 Jun 28.
Article in English | MEDLINE | ID: mdl-37446728

ABSTRACT

Turkey is the leading producer and exporter of hazelnuts, producing approximately 64% of global hazelnut production. This research investigated the effects of cultivars and altitude on the phenolic, antioxidant, and fatty acid compositions of five hazelnut cultivars grown at three different altitudes, 100 m, 350 m, and 800 m, in Ordu province, one of the territories that produce the most hazelnuts. The results showed that the cultivar and location significantly affected phenolic compounds, antioxidant activity, and fatty acid (FA) content. The lowest (2.30 mg/kg-Yagli) and highest (21.11 mg/kg-Kara) gallic acids were obtained at 100 m. The highest total phenolic content and antioxidant activity were found in the nuts grown at 350 m in the Kara and Palaz cultivars, at 100 m in the Yagli and Sivri cultivars, and at 800 m in the Çakildak cultivar. Oleic acid was the predominant FA in the cultivars and possessed a diverse trend according to the altitude and cultivar, ranging from 76.04% to 84.80%, increasing with altitude in all cultivars except Çakildak. Palmitic acid was the predominant saturated FA followed by stearic acid, which significantly varied according to the elevations. This study suggests that the responses of hazelnuts to altitude depend on the cultivar; hence, a proper approach to producing nuts containing more phenolic, fatty acids, and antioxidant activity includes choosing a suitable cultivar for a specific elevation.


Subject(s)
Antioxidants , Corylus , Fatty Acids , Altitude , Turkey , Phenols/analysis
10.
Dalton Trans ; 52(24): 8442-8448, 2023 Jun 20.
Article in English | MEDLINE | ID: mdl-37272264

ABSTRACT

Many Cu catalyzed ATRC reactions suffer from low catalyst activity and stability. We have synthesized five 1,10-phenanthroline ligands substituted in the 5-position with α-aminophosphonate groups, through which the corresponding Cu complexes can be immobilized on Al2O3. These catalysts show similar activity and higher selectivity than the homogenous catalysts while being recyclable.

11.
Inorg Chem ; 62(19): 7283-7295, 2023 May 15.
Article in English | MEDLINE | ID: mdl-37133820

ABSTRACT

Organometallic complexes are frequently deposited on solid surfaces, but little is known about how the resulting complex-solid interactions alter their properties. Here, a series of complexes of the type Cu(dppf)(Lx)+ (dppf = 1,1'-bis(diphenylphosphino)ferrocene, Lx = mono- and bidentate ligands) were synthesized, physisorbed, ion-exchanged, or covalently immobilized on solid surfaces and investigated by 31P MAS NMR spectroscopy. Complexes adsorbed on silica interacted weakly and were stable, while adsorption on acidic γ-Al2O3 resulted in slow complex decomposition. Ion exchange into mesoporous Na-[Al]SBA-15 resulted in magnetic inequivalence of 31P nuclei verified by 31P-31P RFDR and 1H-31P FSLG HETCOR. DFT calculations verified that a MeCN ligand dissociates upon ion exchange. Covalent immobilization via organic linkers as well as ion exchange with bidentate ligands both lead to rigidly bound complexes that cause broad 31P CSA tensors. We thus demonstrate how the interactions between complexes and functional surfaces determine and alter the stability of complexes. The applied Cu(dppf)(Lx)+ complex family members are identified as suitable solid-state NMR probes for investigating the influence of support surfaces on deposited inorganic complexes.

12.
ACS Omega ; 8(19): 16762-16778, 2023 May 16.
Article in English | MEDLINE | ID: mdl-37214708

ABSTRACT

In this study, a magnetic adsorbent material was produced, by environmentally friendly and inexpensive precursor materials, to clean wastewater that may result from primary and secondary rare earth metal (REM) production. Then, the absorption of Nd3+ ions from wastewater was done and this process's kinetic and isotherm models were developed. Thus, the removal of Nd3+ from wastewater with magnetic materials was accomplished, and then, this precious metal was recovered by using different acid media. First, Fe sub-micron particles were successfully produced by the polyol method. To increase the stability of Fe-based particles, their surfaces were covered with an oxide layer, and the average thickness was determined as 16 nm. The synthesized Fe particles were added into the calcium alginate beads and then coated with chitosan to increase the pH stability of the gels. The chemical composition of the gels was determined by Fourier transform infrared spectroscopy, the thermal properties were determined by differential scanning calorimetry, and the magnetic properties were determined by vibrating-sample magnetometer analysis. The magnetic saturation of the hydrogels was 0.297 emu/g. After the production of magnetic calcium alginate hydrogels, Nd3+ ion removal from wastewater was done. Wastewater was cleaned with 94.22% efficiency. The kinetic models of the adsorption study were derived, and isotherm studies were done. Adsorption reaction fitted different kinetic models at different time intervals and the Freundlich isotherm model. The effect of pH, temperature, and solid-liquid ratio on the system was determined and the thermodynamic constants of the system were calculated. After the adsorption studies, Nd3+ ions were regenerated in different acid environments and achieved an 87.48% efficiency value. The removal of Nd3+ ions from wastewater was carried out with high efficiency, the gels obtained as a result of adsorption were regenerated with high efficiency by using acid media, and it was predicted that the gels could be reused. This study is thought to have reference results not only for the removal of REM from wastewater by magnetic adsorption materials but also for the adsorption of heavy metals from wastewater.

13.
RSC Adv ; 13(2): 1320-1332, 2023 Jan 03.
Article in English | MEDLINE | ID: mdl-36686927

ABSTRACT

The increasing production of neodymium-iron-boron (NdFeB) magnets for technological applications results in disposal problems. NdFeB magnets contain a significant quantity of rare earth elements (REEs). China is the largest REEs producer, but it applies quotas and increases the export prices of REEs. To address this issue, this study aims at investigating the recovery process of REEs from scrap NdFeB magnets. After oxidation of NdFeB magnet powders, selective leaching with nitric acid was carried out to achieve high-purity REE-rich leaching liquor. First, the oxidation kinetics of NdFeB powders was studied in detail to determine the oxidation temperature and duration. Afterwards, the effects of selective leaching parameters, including acid concentration, leaching temperature, stirring speed and solid/liquid ratio, were examined by analysis of variance (ANOVA) analysis based on Taguchi method. The most substantial parameters were assigned to be the temperature and solid/liquid ratio. Eventually, the dissolution kinetics were studied to propose a model for REEs. Several universal equations for dissolution kinetics were tested, and (1 - (1 - x) = k × tn) gives the best results for REEs. The findings show that the leaching process follows the shrinking core model. Activation energy was calculated to be 40.375 kJ mol-1 for REEs. As the last step, the iron dissolved during leaching was precipitated as hematite in the autoclave. The hematite precipitation experiments were performed based on the Box-Behnken design. The effect of precipitation parameters was investigated by ANOVA analysis, and the precipitation process was optimized using response surface methodology (RSM), which resulted in the minimum iron and maximum REEs content in the leach liquor.

14.
Crit Rev Anal Chem ; 53(7): 1455-1471, 2023.
Article in English | MEDLINE | ID: mdl-35180027

ABSTRACT

A systematic literature survey published in several journals of pharmaceutical chemistry and of chromatography used to analyze impurities for most of the drugs that have been reviewed. This article covers the period from 2016 to 2020, in which almost of chromatographic techniques have been used for drug impurity analysis. These chromatography techniques are important in the analysis and description of drug impurities. Moreover, some recent developments in forced impurity profiling have been discussed, such as buffer solutions, mobile phase, columns, elution modes, and detectors are highlighted in drugs used for the study. This primarily focuses on thorough updating of different analytical methods which include hyphenated techniques for detecting and quantifying impurity and degradation levels in various pharmaceutical matrices.


Subject(s)
Chemistry, Pharmaceutical , Drug Contamination , Chemistry, Pharmaceutical/methods , Chromatography, High Pressure Liquid/methods
15.
RSC Adv ; 12(48): 31478-31488, 2022 Oct 27.
Article in English | MEDLINE | ID: mdl-36382150

ABSTRACT

NdFeB magnets are employed in various technological applications due to their outstanding magnetic properties, such as high maximum energy product, high remanence and high coercivity. Production of NdFeB has gathered more interest, therefore the demand for rare earth elements (REEs) has continuously increased. The recovery of REEs has become essential to satisfy this demand in recent years. In the present study, a promising flowsheet is proposed for REEs recovery from NdFeB magnets, as follows: (1) acid baking, (2) employment of ultrasound-assisted water leaching, (3) the production of rare earth oxides (RE oxides) by a solution combustion method, and (4) a calcination process. There are several problems in conventional precipitation such as loss of a high amount of metal during precipitation and use of a high amount of precipitation agents. It is worth mentioning that the consumed precipitation agents in the solution are not easily recyclable. This study aims especially to investigate the production of RE oxides from recycled NdFeB magnets by solution combustion as an alternative to conventional precipitation methods. In this way, impurities that may have come to the system from the precipitation agents were prevented. Moreover, in the production of RE oxides via the above-mentioned method, precipitation agents and filtration steps were not necessary.

16.
ACS Omega ; 7(42): 37427-37435, 2022 Oct 25.
Article in English | MEDLINE | ID: mdl-36312386

ABSTRACT

Resistance to currently available antifungal agents raises the need to develop alternative remedies. Candida albicans is the most common opportunistic pathogenic fungus of humans, colonizing in the genital and intestinal mucosa, skin, and oral-nasal cavity and reducing quality of life. Herein, essential oil from grapefruit (Citrus paradise) peels was obtained by hydrodistillation, and the remaining plant material was sequentially subjected to supercritical carbon dioxide (SC-CO2) extraction to determine the conditions for maximizing phenolic compounds. A statistical design was used to evaluate the effect of temperature (30, 50, 70 °C), pressure (80, 150, 220 bar), and ethanol as a cosolvent (0%, 10%, and 20% v/v). Essential oil and SC-CO2 extracts were mixed at various ratios to develop an effective antifungal formulation. Subsequently, fungal infection was modeled by coculturing C. albicans with human skin keratinocytes (HaCaT) to mimic dermal mycoses, endothelial cells (HUVEC) to evaluate vascular fate, and cervical adenocarcinoma (HeLa) cells to represent additional genital mycoses. Treatment with essential oil and extract (25:75%) formulation for 8 h exhibited slight cytotoxicity toward HeLa cells, no toxicity toward HaCaT and HUVECs, whereas inhibition of C. albicans. Considering the clinical significance, such in vitro models are essential to screen potential compounds for the treatment of opportunistic fungal infections.

17.
Scand J Clin Lab Invest ; 82(6): 498-503, 2022 10.
Article in English | MEDLINE | ID: mdl-35938383

ABSTRACT

This report aimed to determine the effects of different preservatives used to maintain the integrity of urine samples for a 24-hour urine collection on urinary iodine measurement by the Sandell-Kolthoff method in vitro. The selected preservatives were hydrochloric acid, acetic acid, boric acid, sodium carbonate, sodium fluoride, thymol with isopropanol, sodium chloride with formalin, and Saccomanno fixative. The test samples to which these preservatives were added and the control samples for basal measurements were prepared from the urine pool obtained from urine samples taken from healthy volunteers. The urinary iodine measurements were performed following the calculated minimum number of replicates in these prepared samples. The data analysis of the interferences of the preservatives was performed based on the Clinical and Laboratory Standards Institute EP7-A2 guideline. The preservatives that had more acceptable effects on the urinary iodine measurement compared to the others were sodium carbonate (0.5% w/v) and thymol (10% w/v) with isopropanol (0.25% v/v) for 24-hour storage at room temperature. This report presented reliable and usable data revealing the effects of preservatives, which are frequently used to maintain the integrity of urine samples for a 24-hour urine collection, on urinary iodine measurement. There are need to reveal the possible effects of potential exogenous interfering substances and the pathological levels of endogenous analytes or shaped elements in the urine matrix on methods with routine clinical use in making medical decisions.


Subject(s)
Iodine , 2-Propanol , Carbonates , Formaldehyde , Humans , Hydrochloric Acid , Iodine/urine , Sodium Chloride , Sodium Fluoride , Thymol
18.
Turk J Chem ; 46(6): 1897-1908, 2022.
Article in English | MEDLINE | ID: mdl-37621333

ABSTRACT

In this study, an abundant and eco-friendly photocatalytic material, Fe2O3 particles were synthesized by sonochemical method. Morphological and microstructural investigations of synthesized undoped and Ni, Co-doped Fe2O3 particles were performed. The effect of particle morphology and microstructure on its photocatalytic performance was further investigated. Comparative studies for evaluating particle crystallite sizes were conducted by Williamson-Hall (W-H) method and modified Debye-Scherrer (MDS). Crystallite sizes and lattice strains of Fe2O3 induced by process parameters were calculated by W-H method based on uniform deformation model (UDM). The crystallite sizes of the synthesized powders were calculated in the range of 200 nm and 76 nm by Williamson-Hall analysis. In addition to structural investigation, dislocation density of the synthesized particles was calculated by Williamson-Smallman relation. Afterwards, photocatalytic performance of Fe2O3 particles was investigated in detail. The photodegradation of methylene blue solutions in the presence of light in 20 min with samples 3,4, and 5 in 20 min were 0.937, 0.896, and 0.855, respectively. Moreover, the photodegradation of methylene blue solution with sample 5 for 15, 30, and 45 min were 0.9, 0.828, and 0.757, respectively. A photocatalytic activity of 24.25% has been observed under optimum conditions for the time interval of 45 min.

19.
J Biomol Struct Dyn ; 40(17): 7926-7939, 2022 10.
Article in English | MEDLINE | ID: mdl-33779508

ABSTRACT

The present study aims to investigate the substrate (4-methyl catechol and catechol) specificity and inhibition mechanisms (l-ascorbic acid, citric acid, and l-cysteine) of the tyrosinase enzyme (TYR), which is held responsible for browning in foods and hyperpigmentation in the human skin, through kinetic and molecular docking studies. During the experimental studies, the diphenolase activities of TYR were determined, following which the inhibitory effects of the inhibitors upon the diphenolase activities of TYR. The inhibition types were determined as competitively for l-ascorbic acid and citric acid and noncompetitive for l-cysteine. The kinetic results showed that the substrate specificity was better for catechol while l-cysteine showed the best inhibition profile. As for the in silico studies, they also showed that catechol had a better affinity in line with the experimental results of this study, considering the interactions of the substrates with TYR's active site residues and their distance to CuB metal ion, which is an indicator of diphenolase activity. Besides, the inhibitory mechanisms of the inhibitor molecules were explained by the molecular modeling studies, considering the binding number of the inhibitors with the active site amino acid residues of TYR, the number and length of H bonds, negative binding energy values, and their distance to CuB metal ion. Based on our results, we suggest that the novel method used in this study to explain the inhibitory mechanism of l-cysteine may provide an affordable alternative to the expensive methods available for explaining the inhibitory mechanism of TYR and those of other enzymes. HighlightsThe best affinity for the tyrosinase enzyme occurred with catechol.l-Ascorbic acid, citric acid, l-cysteine inhibited the diphenolic activity of tyrosinase.In silico studies confirmed the best affinity shown by catechol.Product inhibition mechanism of l-cysteine explained by in silico for the first time.Communicated by Ramaswamy H. Sarma.


Subject(s)
Agaricales , Monophenol Monooxygenase , Agaricus , Ascorbic Acid , Catechols/pharmacology , Citric Acid/pharmacology , Cysteine , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Guaiacol/pharmacology , Humans , Kinetics , Molecular Docking Simulation , Monophenol Monooxygenase/metabolism
20.
Medicina (Kaunas) ; 57(12)2021 Dec 05.
Article in English | MEDLINE | ID: mdl-34946276

ABSTRACT

Background and Objectives: Permanent pacemaker implantation (PPI) is frequently required following transcatheter aortic valve replacement (TAVR). Dual antiplatelet therapy (DAPT) or oral anticoagulation therapy (OAK) is often necessary in these patients since they are at higher risk of thromboembolic events due to TAVR implantation, high incidence of coronary artery diseases (CAD) with the necessity of coronary intervention, and high rate of atrial fibrillation with the need of stroke prevention. We sought to evaluate the safety, efficiency, and clinical outcomes of early PPI following TAVR using the PlasmaBlade™ (Medtronic Inc., Minneapolis, MN, USA) pulsed electron avalanche knife (PEAK) for bleeding control in patients under DAPT or OAK. Materials and Methods: This retrospective single-center study included patients who underwent PPI after transfemoral TAVR (TF) at our center between December 2015 and May 2020. All PPI were performed using the PlasmaBlade™ Device. Results: The overall PPI rate was 14.1% (83 of 587 patients; 82.5 ± 4.6 years; 45.8% male). The PPI procedures were used to treat high-grade atrioventricular block (81.9%), severe sinus node dysfunction (13.3%), and alternating bundle branch block (4.8%). At the time of the procedure, 35 (42.2%) patients received DAPT, and 48 (57.8%) patients received OAK (50% with vitamin K antagonist (VKA) and 50% with novel oral anticoagulants (NOAK)). One device-pocket hematoma treated conservatively occurred in a patient (1.2%) receiving NOAK. Two re-operations were necessary in patients due to immediate lead dislocation (2.4%). Conclusions: The results of this study illustrate that the use of PlasmaBlade™ for PPI in patients after a TAVR who require antithrombotic treatment is feasible and might result into lower rates of severe bleeding complications compared to rates reported in the literature. Use of the PlasmaBlade device may be considered in this specific group of patients because of their high risk of bleeding.


Subject(s)
Hemorrhage/prevention & control , Pacemaker, Artificial , Transcatheter Aortic Valve Replacement , Aged , Aged, 80 and over , Aortic Valve/surgery , Female , Hemorrhage/epidemiology , Humans , Male , Retrospective Studies , Risk Factors , Transcatheter Aortic Valve Replacement/adverse effects , Treatment Outcome
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