94 research outputs found
The Influence of Biological Environment on the Silver-Coated Implants
The environment of the human body is very aggressive, containing among others bacteria, which contribute to the degradation of metal implants. Therefore sometimes implants are covered with nanometals to prevent development of aggressive bacteria. This paper deals with implants covered with nanosilver (15nm), which is antibacterial. The tested implants included: PE vein implant, an intramedullary implant made of stainless steel and brass implant for tracheotomy. The results showed an appearance of implants covered with silver as dependent on the type of bacteria: although silver significantly protected implants against some bacteria, a presence of some amounts of Staphylococcus aureus and Staphylococcus epidermidis was noticed after long term exposure in the human body. Only single bacteria could be observed on the surface of the tested materials. Such behavior is evidence, that silver coatings are effective for different form of materials in the presence of various bacteria, however, such behavior is related to form of  bacteria
The use of quartz crystal microbalance with dissipation (QCM-D) for studying nanoparticle-induced platelet aggregation
Interactions between blood platelets and nanoparticles have both pharmacological and toxicological significance and may lead to platelet activation and aggregation. Platelet aggregation is usually studied using light aggregometer that neither mimics the conditions found in human microvasculature nor detects microaggregates. A new method for the measurement of platelet microaggregation under flow conditions using a commercially available quartz crystal microbalance with dissipation (QCM-D) has recently been developed. The aim of the current study was to investigate if QCM-D could be used for the measurement of nanoparticle-platelet interactions. Silica, polystyrene, and gold nanoparticles were tested. The interactions were also studied using light aggregometry and flow cytometry, which measured surface abundance of platelet receptors. Platelet activation was imaged using phase contrast and scanning helium ion microscopy. QCM-D was able to measure nanoparticle-induced platelet microaggregation for all nanoparticles tested at concentrations that were undetectable by light aggregometry and flow cytometry. Microaggregates were measured by changes in frequency and dissipation, and the presence of platelets on the sensor surface was confirmed and imaged by phase contrast and scanning helium ion microscopy
The Unfolded Protein Response in Amelogenesis and Enamel Pathologies
During the secretory phase of their life-cycle, ameloblasts are highly specialized secretory cells whose role is to elaborate an extracellular matrix that ultimately confers both form and function to dental enamel, the most highly mineralized of all mammalian tissues. In common with many other âprofessionalâ secretory cells, ameloblasts employ the unfolded protein response (UPR) to help them cope with the large secretory cargo of extracellular matrix proteins transiting their ER (endoplasmic reticulum)/Golgi complex and so minimize ER stress. However, the UPR is a double-edged sword, and, in cases where ER stress is severe and prolonged, the UPR switches from pro-survival to pro-apoptotic mode. The purpose of this review is to consider the role of the ameloblast UPR in the biology and pathology of amelogenesis; specifically in respect of amelogenesis imperfecta (AI) and fluorosis. Some forms of AI appear to correspond to classic proteopathies, where pathological intra-cellular accumulations of protein tip the UPR toward apoptosis. Fluorosis also involves the UPR and, while not of itself a classic proteopathic disease, shares some common elements through the involvement of the UPR. The possibility of therapeutic intervention by pharmacological modulation of the UPR in AI and fluorosis is also discussed
Teeth of the red fox Vulpes vulpes (L., 1758) as a bioindicator in studies on fluoride pollution
An examination was made of fluoride content in the mandibular first molars of the permanent teeth of the red fox Vulpes vulpes living in north-west (NW) Poland. The teeth were first dried to a constant weight at 105°C and then ashed. Fluorides were determined potentiometrically, and their concentrations were expressed in dry weight (DW) and ash. The results were used to perform an indirect estimation of fluoride pollution in the examined region of Poland. The collected specimens (nâ=â35) were classified into one of the three age categories: immature (im, 6â12 months), subadult (subad, from 12 to 20 months) and adult (ad, >20 months). The mean concentrations (geometric mean) of fluoride were similar in the im and subad groups (230 and 296 mg/kg DW and 297 and 385 mg/kg ash, respectively), and significantly smaller than in the ad group (504 and 654 mg/kg, respectively, in DW and ash). Basing on other reports that the âŒ400 mg/kg DW concentration of fluoride in bones in the long-lived wild mammals generally reflects the geochemical background, it was found that 57% of the foxes in NW Poland exceeded this value by 9% to 170%. This indirectly reflects a moderate fluoride contamination in the tested region
Fluoride concentrations in the pineal gland, brain and bone of goosander (Mergus merganser) and its prey in Odra River estuary in Poland
Effects of acupuncture and electroacupuncture on estradiol-induced inflammation and oxidative stress in health rodents
Characterization and cytotoxic effect of aqua-(2,2âČ,2âČâČ-nitrilotriacetato)-oxo-vanadium salts on human osteosarcoma cells
Interakcje fluorkĂłw z wybranymi skĆadnikami diety i farmakoterapeutykami - rola stresu oksydacyjnego
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Modified Nanoparticles as Potential Agents in Bone Diseases: Cancer and Implant-Related Complications
Materials sized 1–100 nm are the nanotechnology’s field of interest. Because of the unique properties such as the ability to penetrate biological barriers and a high surface to volume ratio, nanoparticles (NPs) are a powerful tool to be used in medicine and industry. This review discusses the role of nanotechnology in bone-related issues: osteosarcoma (bone cancer), the biocompatibility of the implants and implant-related infections. In cancer therapy, NPs can be used as (I) cytotoxic agents, (II) drug delivery platforms and (III) in thermotherapy. In implant-related issues, NPs can be used as (I) antimicrobial agents and (II) adjuvants to increase the biocompatibility of implant surface. Properties of NPs depend on (I) the type of NPs, (II) their size, (III) shape, (IV) concentration, (V) incubation time, (VI) functionalization and (VII) capping agent type
Human carnosinases: A brief history, medicinal relevance, and in silico analyses
Carnosine, an endogenous dipeptide, has been found to have a plethora of medicinal properties, such as antioxidant, antiageing, and chelating effects, but with one downside: a short half-life. Carnosinases and two hydrolytic enzymes, which remain enigmatic, are responsible for these features. Hence, here we emphasize why research is valuable for better understanding crucial concepts like ageing, neurodegradation, and cancerogenesis, given that inhibition of carnosinases might significantly prolong carnosine bioavailability and allow its further use in medicine. Herein, we explore the literature regarding carnosinases and present a short in silico analysis aimed at elucidating the possible recognition pattern between CN1 and its ligands
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