Analysis of a ß-TCP bone graft extender explanted during revision surgery after 28 months in vivo.

PURPOSE: Analysis of a ß-tricalcium phosphate (ß-TCP) bone graft soaked with bone marrow aspirate explanted during revision surgery after 28 months. METHODS: A 41-year-old female patient undergoing scoliosis correction Th4-L5 in 2007 was revised due to screw loosening in 2008. During revision surgery, a ß-TCP bone graft (chronOS(®) chips) soaked with bone marrow aspirate was applied. Due to implant failure, the patient was revised again 2011. The bone graft was removed and taken to the laboratory for histological analysis. The biomaterial samples were stained with DAPI and analyzed under a fluorescence microscope. Five biomaterial chips were maintained in tissue culture to evaluate outgrowing cells. The remaining samples were embedded in paraffin, sectioned into 7 µm sections and stained with Hemalaun/eosin. RESULTS: The morphology and rigidity of the ß-TCP bone graft were comparable to the original. The pores were not filled with tissue and could be clearly identified. Only single vital cells were detected on the graft. The outgrowth culture yielded only erythrocytes-no cells of the osteoblastic lineage cells could be harvested. Histological analysis demonstrated a failure of resorption and the absence of new bone formation. CONCLUSION: Histological analysis of bone grafts is rare after implantation in humans due to ethical and clinical limitations of sample harvest. In this study, implantation of a ß-TCP bone graft did not result in bone formation after 28 months in vivo.

Microplastics in water resources: Global pollution circle, possible technological solutions, legislations, and future horizon.

Beneath the surface of our ecosystems, microplastics (MPs) silently loom as a significant threat. These minuscule pollutants, invisible to the naked eye, wreak havoc on living organisms and disrupt the delicate balance of our environment. As we delve into a trove of data and reports, a troubling narrative unfolds: MPs pose a grave risk to both health and food chains with their diverse compositions and chemical characteristics. Nevertheless, the peril extends further. MPs infiltrate the environment and intertwine with other pollutants. Worldwide, microplastic levels fluctuate dramatically, ranging from 0.001 to 140 particles.m-3 in water and 0.2 to 8766 particles.g-1 in sediment, painting a stark picture of pervasive pollution. Coastal and marine ecosystems bear the brunt, with each organism laden with thousands of microplastic particles. MPs possess a remarkable ability to absorb a plethora of contaminants, and their environmental behavior is influenced by factors such as molecular weight and pH. Reported adsorption capacities of MPs vary greatly, spanning from 0.001 to 12,700 µg·g-1. These distressing figures serve as a clarion call, demanding immediate action and heightened environmental consciousness. Legislation, innovation, and sustainable practices stand as indispensable defenses against this encroaching menace. Grasping the intricate interplay between microplastics and pollutants is paramount, guiding us toward effective mitigation strategies and preserving our health ecosystems.

Composite of methyl polysiloxane and avocado biochar as adsorbent for removal of ciprofloxacin from waters.

Two carbon composite materials were prepared by mixing avocado biochar and methyl polysiloxane (MK). Firstly, MK was dissolved in ethanol, and then the biochar was added at different times. In sample 1 (R1), the time of adding biochar was immediately after dissolving MK in ethanol, and in sample 2 (R2), after 48 h of MK dissolved in ethanol. The samples were characterized by nitrogen adsorption/desorption measurements obtaining specific surface areas (SBET) of 115 m2 g-1 (R1) and 580 m2 g-1 (R2). The adsorbents were further characterized using scanning electron microscopy, FTIR and Raman spectroscopy, adsorption of vapors of n-heptane and water, thermal analysis, Bohem titration, pHpzc, and C H N elemental analysis. R1 and R2 adsorbents were employed as adsorbents to remove the antibiotic ciprofloxacin from the waters. The t1/2 and t0.95 based on the interpolation of Avrami fractional-order were 20.52 and 246.4 min (R1) and 14.00 and 157.6 min (R2), respectively. Maximum adsorption capacities (Qmax) based on the Liu isotherm were 10.77 (R1) and 63.80 mg g-1 (R2) for ciprofloxacin. The thermodynamic studies showed a spontaneous and exothermic process for both samples, and the value of ΔH° is compatible with physical adsorption.

Microplastics physicochemical properties, specific adsorption modeling and their interaction with pharmaceuticals and other emerging contaminants.

This review discusses the imminent threat that microplastics (MPs) associated with pharmaceuticals represent to the aquatic environment and public health. We initially focused upon recognizing and stressing that MPs are ubiquitous pollutants. The influence of environmental factors, such as pH, mechanical stress, and photodegradation, are examined, aiming to elucidate how both substances might associate, what are their simultaneous degradation pathways and, to understand the interactions between MPs and pharmaceuticals. Mathematical tools, such as modeling and simulations, are presented in detail, aiming to improve how information is interpreted. Furthermore, it is exhibited that MPs sorption and interaction behavior towards organic contaminants play an important role in understanding its dynamics in the environment, as well as their possible interactions with pharmaceuticals that are summarized. At last, MPs and pharmaceuticals toxicity and bioaccumulation are presented.

Cellulose-g-poly-(acrylamide-co-acrylic acid) polymeric bioadsorbent for the removal of toxic inorganic pollutants from wastewaters.

Cellulose biopolymer was functionalized by free graft copolymerization and used as a new adsorbent to eliminate toxic inorganic pollutants from wastewater. Functional graft copolymers from cellulose were characterized by FT-IR spectroscopy, XRD, TGA, and SEM-EDX techniques.Cellulose-g-poly-(acrylamide-co-acrylic acid) polymer adsorbent showed high adsorption capacities for the Cd2+, Cu2+, Pb2+ and Zn2+ toxic metal ions, which were evidenced by the comparison with unmodified cellulose-richsamples. Cellulose-g-poly-(acrylamide-co-acrylic acid) polymer adsorbent was optimized with various adsorption parameters such as the effect of pH, contacttime, temperature, and metallic ions concentration. The maximum monolayer capacity qm calculated for Cd2+, Cu2+, Pb2+, Zn2+ were 101.73, 61.84, 209.64, and 55.04 mgg-1 respectively. Thus, these results proved that cellulose-g-poly-(acrylamide-co-acrylic acid) graft copolymer adsorbent from cellulose-rich biomass could potentially be used for the removal of pollutants from wastewater.

Barrier properties to surrogates of hydrogenated carbon nano-films deposited on PET by plasma-enhanced chemical vapour deposition.

Poly(ethylene terephthalate) resin was contaminated with a series of surrogates using a US Food and Drug Administration protocol. The contaminated samples were coated with two different kinds of hydrogenated amorphous carbon thin films (a-C:H): one with diamond-like hydrogenated amorphous carbon and another with polymer-like hydrogenated carbon (PLCH) phases. To evaluate the barrier properties of the a-C:H films, migration assays were performed using food simulants. After the tests, analysis by gas chromatography with different detectors was carried out. The appearance of the films before and after the migration experiments was studied by field emission scanning electron microscopy. The results showed that a-C:H films have good barrier properties for most of the evaluated compounds, mainly when they are deposited as PLCH phase.

Adsorption of Procion Blue MX-R dye from aqueous solutions by lignin chemically modified with aluminium and manganese.

A macromolecule, CML, was obtained by purifying and carboxy-methylating the lignin generated from acid hydrolysis of sugarcane bagasse during bioethanol production from biomass. The CMLs complexed with Al(3+) (CML-Al) and Mn(2+) (CML-Mn) were utilised for the removal of a textile dye, Procion Blue MX-R (PB), from aqueous solutions. CML-Al and CML-Mn were characterised using Fourier transform infrared spectroscopy (FTIR), scanning differential calorimetry (SDC), scanning electron microscopy (SEM) and pHPZC. The established optimum pH and contact time were 2.0 and 5h, respectively. The kinetic and equilibrium data fit into the general order kinetic model and Liu isotherm model, respectively. The CML-Al and CML-Mn have respective values of maximum adsorption capacities of 73.52 and 55.16mgg(-1) at 298K. Four cycles of adsorption/desorption experiments were performed attaining regenerations of up to 98.33% (CML-Al) and 98.08% (CML-Mn) from dye-loaded adsorbents, using 50% acetone+50% of 0.05molL(-1) NaOH. The CML-Al removed ca. 93.97% while CML-Mn removed ca. 75.91% of simulated dye house effluents.

A tissue engineering approach to meniscus regeneration in a sheep model.

OBJECTIVE: Regeneration of the meniscal tissue occurs to a limited extent, and the loss of meniscal tissue leads to osteoarthritis. A new biomaterial consisting of hyaluronic acid and polycaprolactone was used as a meniscus substitute in sheep to evaluate the properties of the implant material with regard to size, biomechanical stability, tissue ingrowth, and integration. METHODS: Eight sheep (right stifle joints) were treated with three total and three partial meniscus replacements while two meniscectomies served as empty controls. The animals were euthanized after 6 weeks. The specimens were assessed by gross inspection and histology, and compared with the nonoperated left joints. RESULTS: The surgical technique was found to be feasible. The implants remained in position, did not tear, and showed excellent tissue ingrowth to the capsule. Tissue integration was also observed between the original meniscus and the implant. However, graft compression and extrusion occurred. The histological investigation revealed tissue formation, cellular infiltration and vascularization. Cartilage degeneration was more severe in the operated joints. CONCLUSION: The present study shows promising results concerning the qualities of this biomaterial with regard to implantation technique, stability and tissue ingrowth.

Regulation of hepatic cholesterol metabolism in CETP/LDLr mice by cholesterol feeding and by drugs (cholestyramine and lovastatin) that lower plasma cholesterol.

1. The hepatic mechanisms involved in the simultaneous regulation of plasma cholesterol concentration and cholesteryl ester transfer protein (CETP) activity were investigated by sharply modifying the hepatic rates of cholesterol synthesis. This was accomplished by cholestyramine, lovastatin and cholesterol feeding in human CETP transgenic mice cross-bred with low-density lipoprotein receptor (LDLr)-knockout mice, generating CETP(+/-)/LDLr(+/-) mice, which present a plasma lipoprotein profile resembling that of humans. 2. Analyses of pooled data showed that the plasma CETP activity correlated positively with plasma total cholesterol concentration, hepatic CETP mRNA and the liver microsomal cholesterol content; a negative correlation was found between plasma CETP activity and the liver 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and LDLr mRNA levels. These coordinated events represent an efficient control system that stabilizes the cell cholesterol content. 3. Nonetheless, not all cholesterol metabolism regulatory systems seem to fit into a coherent pattern of responses, suggesting that other unknown cellular mechanisms play roles depending on the type of pharmacological intervention. 4. For example, microsomal cholesterol content was not affected by cholestyramine, but was increased on cholesterol feeding (as predicted), and, surprisingly, on lovastatin treatment. Furthermore, although both plasma cholesterol-lowering drugs increased CYP7A1 mRNA and had no effect on CYP27 mRNA, other metabolic components were differentially modified. Cholestyramine and lovastatin, respectively, did not modify and increased both HMG-CoA and sterol responsive element binding protein 1c mRNA, did not modify and lowered liver X receptor alpha mRNA, lowered and increased ATP binding cassette A1 mRNA and lowered and did not modify scavenger receptor B1 mRNA. 5. That is, different to unabsorbed cholestyramine, lovastatin, as an absorbed plasma cholesterol-lowering drug, may have modified the activity of other unknown genes that play roles in the interaction of CETP with the metabolism of hepatic cholesterol.