Employing volcanic tuff minerals in interior architecture design to reduce microbial contaminants and airborne fungal carcinogens of indoor environments.

Indoor volatile organic compounds (VOCs) have posed significant risks to human health since people have both shifted to a life spent, for the most part, indoors. Further, changes in materials used in the construction of buildings, furnishings, and tools either leak or encourage the production of VOCs. Whether these enclosed areas are residences, hospitals or workplaces (specifically composting facilities or closed farm buildings for raising livestock), VOCs can rise to levels that threaten people's health. VOCs can either originate from phenolic and benzene-like compounds in building materials and office furniture or from molds (fungi) growing inside improperly ventilated or sealed buildings. Regardless of the source, exposure to VOCs could lead to significant health concerns from sick-building syndrome, 'leukemia houses,' in-hospital fungemia cases or occupation-associated cancer epidemics due to aflatoxicosis. Innovative 21st-century building materials could offer solutions to these challenges. We propose that volcanic materials, clays and minerals (volcanic tuff, modified clay montmorillonite and mineral clinoptilolite), in their original or chemically modified form, could act like synthetic lungs in building walls, breathing and filtering VOCs, and thus limiting human exposure to disease.

The influence of titanium surfaces in cultures of neonatal rat calvarial osteoblast-like cells: an immunohistochemical study.

BACKGROUND: The goal of this present study was to evaluate the behavior of neonatal rat calvarial osteoblast-like cells cultured on different implant surfaces. MATERIALS: Sandblasted acid-etched (SLA) surfaces of 2 different companies with different alloy properties were used. These were named as SLA-1 and SLA-2. The osteoblasts behavior were analyzed on sand blasted-acid etched (SLA-1) surface (Straumann, Basel, Switzerland), sand blasted-acid etched (SLA-2) surface (Alpha bio, Petach-tikva, Israel), acid-etched surface (Alpha bio), machined surface (Alpha bio). To analyze the effect of titanium surfaces on cell proliferation, cell numbers, and cell viability cells were cultured on titanium discs for 7 days and measurements were held out at 24 hours and on day 7. Cell proliferation rate was assessed by bromodeoxyuridine (BrdU) immunohistochemical technique. Cell morphologies were evaluated by scanning electron microscopy. RESULTS: The highest number of BrdU labeled cells were seen on SLA-1 group at the end of 24 hours. The number of cells was found to be the highest in the acid-etched group on the 7th day, even though there were no significant differences between the groups at the end of 24 hours. Scanning electron microscopy views showed the morphological differences between the groups. Osteoblasts were able to proliferate on all of the tested surfaces, with differences in cell count and DNA synthesis values between the groups. CONCLUSION: Implant surface characteristics may modulate the biological response of osteoblast-like cells depending on the manufacturing techniques and cell culturing procedures.

[Analysis of degradation failure of poly L-lactic acid fixators used in meniscus tears]. / Menisküs yirtiklarinin atroskopik tamirinde kullanilan poli L-laktik asit sabitleyicilerin erimeme nedenlerinin arastirilmasi.

OBJECTIVES: Biodegradable poly L-lactic acid (PLLA) fixators used in the repair of meniscal tears may cause adverse reactions inside the knee due to delayed degradation. This study was designed to determine the reasons for late degradation of PLLA fixators. METHODS: Three unused and three used meniscal PLLA fixators (BioStinger) were analyzed. The latter were removed from three patients due to persisting symptoms within six months after knee arthroscopy. Fourier transform infrared (FTIR) spectroscopy was performed and external and internal surfaces of the samples were examined by scanning electron microscopy (SEM) and X-ray fluoroscopy (XRF). Chemical structural analyses of two samples (one from each group) were made by 1H-nuclear magnetic resonance (1H-NMR) spectroscopy. Degradation times of two samples (one from each group) by oxidative hydrolysis in hydrogen peroxide solution were recorded. RESULTS: Chemical structure of used and unused fixators did not differ in FTIR analysis. With increasing temperatures, unused and used fixators showed degradation with and without melt flow, respectively. In SEM analysis, inner sections of unused fixators were homogeneous, whereas those of the used ones exhibited crystals which were found to be sodium and potassium chloride salts in XRF analysis. The 1H-NMR spectrum of used and unused samples showed the normal pattern of lactic acid polymer. The unused and used fixators degraded in hydrogen peroxide solution in 10 days and 30 days, respectively. CONCLUSION: Both fixators had the same chemical structure in FTIR and NMR analyses. Formation of salt crystals seemed to be the most important cause of degradation failure, while changes in the physical properties of fixators were thought to be associated with delayed degradation.

Photopolymerized injectable RGD-modified fumarated poly(ethylene glycol) diglycidyl ether hydrogels for cell growth.

In this study, photopolymerized hydrogels of fumarated poly(ethylene glycol) diglycidyl-co- poly(ethylene glycol) diacrylate have been synthesized and modified with cell adhesion peptide, Arg-Gly-Asp (RGD). The structural and mechanical properties of the hydrogels are found to be poly(ethylene glycol) diacrylate (PEGDA) dependent. The percentage of gelation is increased from 72 to 89 wt.-% when the amount of the crosslinker co-monomer (PEGDA) in the hydrogel formulation is increased from 20 to 40 wt.-%. In the present case, the equilibrium mass swelling is decreased from 216 to 93%. The viscosities of the uncured formulations have also been measured and likewise, the results were influenced by the increasing amount of PEGDA that reduced the value from 83 to 36 cP. The compressive modulus of the prepared hydrogels was improved with the addition of the PEGDA. Cell growth experiments have been performed by comparing the properties of the hydrogels with and without RGD units. The results show that RGD units enhance the adhesion of cells to the surface of the hydrogels. SEM-EDS studies reveal that nitrogen and calcium are produced on the osteoblast-seeded surface of the scaffold within the culture time period. [Figure: see text].

In vitro evaluation of the use of zeolites as biomaterials: effects on simulated body fluid and two types of cells.

Various zeolites were kept in simulated body fluid (SBF) for different periods of time. Possible changes that may occur in the crystalline structures of zeolites and the chemical composition of SBF were determined by various analysis techniques after this treatment. The possible effects of two different zeolites on the morphology and viability of chronic myelogeneous leukemia and swiss albino fibroblast culture cells were also investigated. It was determined that when different types of zeolites were kept in the SBF for up to 14 days, their crystal structures were not affected. Observable amounts of Si were detected in the SBF samples after their treatment with all the zeolites investigated. Another variation in the chemical composition of SBF, worth to mention, was the increase of about 10% in its K content after the treatment carried out by using clinoptilolite. The zeolites KA and silicalite, which allowed the lowest and highest amount of silicon transfer into the SBF, respectively, were observed not to have any significant biological effect on the two different cell generations investigated under the conditions used in this study.

[Evaluation of differentiation potential of human bone marrow-derived mesenchymal stromal cells to cartilage and bone cells]. / Insan kemik iligi kaynakli mezenkimal stromal hücrelerin kikirdak ve kemik hücrelerine farklilasma potansiyelinin degerlendirilmesi.

OBJECTIVES: This study was designed to identify the characteristics and surface antigen properties of mesenchymal stromal cells (MSC) isolated and cultured from bone marrow of healthy subjects and to assess their differentiation potential to osteoblast and chondroblast lineage cells. METHODS: Mononuclear cells were isolated by density-gradient separation from 1-3 ml of bone marrow collected from 10 donors of bone transplantation aged between 4 months and 18 years. These mononuclear cells were cultured in flasks containing 10% fetal calf serum, which resulted in growth of fibroblast-like cells showing adhesion onto the culture flask. Physical properties of the cells were identified and flow cytometric immunophenotyping was performed to specify surface antigen properties. Differentiation of mesenchymal stromal cells in specific media to chondroblasts and osteoblasts was evaluated. Osteoblasts and chondroblasts were stained with Alizarin red and Alcian blue, respectively, and microphotographed. RESULTS: In vitro yield of MSCs showed no age-related differences in terms of morphological and adhesive properties. While cells of stromal origin showed strong positivity (90% to 99%) to characteristic CD105, CD44, CD166, CD29, CD90, and CD73 antibodies, hematopoietic cells remained negative (0% to 5%) to CD45, CD34, CD14, and HLA-DR antibodies. It was observed that MSCs produced in cell-specific media differentiated to osteoblasts and chondroblasts in all passages (p1-15) tested, including late passages. CONCLUSION: It seems that the use of MSCs would provide promising treatment strategies in bone marrow transplantation, inherited diseases, and organ repair; in in vitro assessment of biological effects of biomaterials in orthopedics; and in repair of bone and cartilage injuries.

[Production and characterization of a glass-ceramic biomaterial and in vitro and in vivo evaluation of its biological effects]. / Bir cam-seramik biyomalzemenin üretimi, tanimlanmasi ve biyolojik etkilerinin canli-disi ve canli-içi ortamda degerlendirilmesi.

OBJECTIVES: Glass-ceramics are biomaterials that are usually produced by the sol-gel technique and can be used as a substitute for bone. One important feature of glass-ceramics is osteointegration with bone tissue. This study was designed to produce a glass-ceramic and evaluate its structure and in vitro and in vivo biological effects. METHODS: With the sol-gel method, a glass-ceramic was synthesized in the form of 30SiO2-17MgO-53Ca3(PO4)2 using tetraethylorthosilicate, dibutyl phosphate, magnesium, and calcium nitrate. Glass-ceramic jel samples were sintered at temperatures up to 1100 degrees C and their microstructure and phases were examined by the X-ray diffraction (XRD) technique and scanning electron microscopy. For in vitro tests, the samples were immersed in a simulative body fluid (SBF) for 10, 30, and 40 days to be analyzed by XRD. For in vivo tests, the samples were placed in tibial metaphyses of Sprague-Dawley rats for 4, 6, and 8 weeks for histological evaluation of osteointegration. RESULTS: As the temperature increased, growth of crystal phases was noted. While XRD analysis showed no change in samples that were kept in SBF for 10 days, hydroxyapatite crystals were seen after 30 and 40 days of SBF treatment in the second and third degree of crystal phases. In vivo test results showed that the glass-ceramic possessed a high tendency to replace osteoid bone tissue, with full osteointegration at eight weeks. CONCLUSION: The glass-ceramic produced has a high surface reactivity and can be used as a bone substitute material.

[Culturability of rat bone marrow stromal cells and evaluation for osteoblastic formation]. / Siçan kemik iligi stromal hücrelerinin kültüre edilebilirligi ve osteoblastik formasyonun degerlendirilmesi.

OBJECTIVES: We investigated culturability of bone marrow stromal cells of young mature rats and evaluated cultured cells with regard to histomorphologic features and osteoblastic formation. METHODS: Sixteen mature Wistar rats were sacrificed under high dose of ether anesthesia. Their femurs and tibias were removed, medullas and metaphyses were washed with carrier serum and the collected material was cultured in DME/F12 serum. The cells in the test medium and at the bottom of Petri dishes were studied under inverted microscope and were photographed. Then, the cells at the bottom were stained with the picro-thionin technique, examined under light microscope, and photographed. Following trypsinizing, cluster cells were dissolved and smears were prepared for histomorphologic evaluation of stromal cells. RESULTS: Rat bone marrow cells in the culture showed a high percentage of reproducibility (93.8%; 15/16). The stromal cells in Petri dishes were of different morphology, and were interspersed with large multinucleated osteoblast-like cells following staining with the picro-thionin technique. CONCLUSION: Our findings favor the opinion that cells harvested in bone marrow cell culture are very similar to osteoblastic cells and that they may stem from osteoprogenitor cells which have multifacet differentiation ability.