Use of adipose stem cells and polylactide discs for tissue engineering of the temporomandibular joint disc

There is currently no suitable replacement for damaged temporomandibular joint (TMJ) discs after discectomy. In the present study, we fabricated bilayer biodegradable polylactide (PLA) discs comprising a non-woven mat of poly(L/D)lactide (P(L/D)LA) 96/4 and a P(L/DL)LA 70/30 membrane plate. The PLA disc was examined in combination with adipose stem cells (ASCs) for tissue engineering of the fibrocartilaginous TMJ disc in vitro. ASCs were cultured in parallel in control and chondrogenic medium for a maximum of six weeks. Relative expression of the genes, aggrecan, type I collagen and type II collagen present in the TMJ disc extracellular matrix increased in the ASC-seeded PLA discs in the chondrogenic medium. The hypertrophic marker, type X collagen, was moderately induced. Alcian blue staining showed accumulation of sulphated glycosaminoglycans. ASC differentiation in the PLA discs was close to that observed in pellet cultures. Comparison of the mRNA levels revealed that the degree of ASC differentiation was lower than that in TMJ disc-derived cells and tissue. The pellet format supported the phenotype of the TMJ disc-derived cells under chondrogenic conditions and also enhanced their hyalinization potential, which is considered part of the TMJ disc degeneration process. Accordingly, the combination of ASCs and PLA discs has potential for the development of a tissue-engineered TMJ disc replacement.     

Characterizing and optimizing poly-l-lactide-co-ε-caprolactone membranes for urothelial tissue engineering

Different synthetic biomaterials such as polylactide (PLA), polycaprolactone and poly-l-lactide-co-ε-caprolactone (PLCL) have been studied for urothelial tissue engineering, with favourable results. The aim of this research was to further optimize the growth surface for human urothelial cells (hUCs) by comparing different PLCL-based membranes: smooth (s) and textured (t) PLCL and knitted PLA mesh with compression-moulded PLCL (cPLCL). The effects of topographical texturing on urothelial cell response and mechanical properties under hydrolysis were studied. The main finding was that both sPLCL and tPLCL supported hUC growth significantly better than cPLCL. Interestingly, tPLCL gave no significant advantage to hUC attachment or proliferation compared with sPLCL. However, during the 14 day assessment period, the majority of cells were viable and maintained phenotype on all the membranes studied. The material characterization exhibited potential mechanical characteristics of sPLCL and tPLCL for urothelial applications. Furthermore, the highest elongation of tPLCL supports the use of this kind of texturing. In conclusion, in light of our cell culture results and mechanical characterization, both sPLCL and tPLCL should be further studied for urothelial tissue engineering.     

Tissue reactions of subcutaneously implanted mixture of ε-caprolactone-lactide copolymer and tricalcium phosphate. An electron microscopic evaluation in sheep

Biodegradable polymers, mainly derivates of -hydroxy acids, are widely used today in oral- and maxillofacial surgery, orthopedics, and other fields of surgery. These biomaterials are well tolerated by living tissue and fracture fixation devices made of polylactic or polyglycolic acid are clinically widely used today. Still, there are some problems in application of biodegradable polymers. Abacterial inflammatory reactions have been noticed after the clinical introduction of these devices. Both swelling and pain at the site of implantation have also been reported. The etiology of this inflammatory reaction is still unknown, despite the numerous studies. Therefore, the aim of the present study was to further characterize this inflammatory reaction in detail, by electronmicroscopy. We prepared a mixture of -caprolactone–lactide copolymer and tricalcium phosphate and placed it in the dermis in 12 sheep. Follow-up times were 9, 14, 24, and 52 weeks. We found that the mixture caused a mild inflammatory reaction. There were no signs of cell damage. Fibroblasts, macrophages, and eosinophils were found adjacent to the copolymer. The mixture is easy to handle and can be moulded into different shapes in room temperature. The results encourage us to continue our studies to develop a filling material for bone defects.     

Body iron stores are associated with serum insulin and blood glucose concentrations. Population study in 1,013 eastern Finnish men

OBJECTIVE: To study if there is an association between mildly elevated body iron and glucose homeostasis indexes. RESEARCH DESIGN AND METHODS: A cross-sectional population study was conducted in 1,013 middle-aged men, and an association of serum ferritin with concentrations of serum insulin, blood glucose, and serum fructosamine was tested. RESULTS: The mean concentration of fasting serum insulin was 21.6% higher (95% CI 7.3-37.9%, P < 0.001) in the 5th quintile of serum ferritin compared with the 1st quintile. The elevation in blood glucose was 6.1% (95% CI 2.3-9.9%, P < 0.001) and in serum fructosamine 3.9% (1.5-6.9%, P < 0.01). CONCLUSIONS: Mildly elevated body iron stores are associated with statistically significant elevations in glucose homeostasis indexes.     

The hygienic working practices of maintenance personnel and equipment hygiene in the Finnish food industry

The hygienic working practices of the maintenance personnel as well as the hygiene of the equipment in the food industry were investigated with questionnaires and microbial surveys. The protective clothing, washing of hands and tools as well as avoiding foreign bodies left on the production lines should be targeted when the hygienic working practices are developed for maintenance personnel. Based on the questionnaire to food processors, packaging machines, conveyers, dispensers, slicing and cooling machines were considered the most problematic pieces of equipment hygienically mainly because of poor hygienic design. In order to improve food safety, both the training of maintenance personnel in food hygiene and equipment design should be more emphasised.     

Direct synthesis of dimethyl carbonate with supercritical carbon dioxide: Characterization of a key organotin oxide intermediate

The direct synthesis of dimethyl carbonate (DMC) using carbon dioxide as solvent and reagent for its fixation to methanol was explored with di-n-butyldimethoxystannane in order to get insight into the reaction mechanism for activity improvement. Catalytic runs including recycling experiments allowed isolation and characterization by NMR, IR, and single-crystal X-ray diffraction of a new tin complex containing 10 tin atoms. This compound could be prepared independently and is considered as a resting species. The yield of DMC is highest under 20 MPa pressure that fits with a monophasic supercritical medium in agreement with fluid phase equilibria calculations. In line, preliminary kinetics and initial rate determination show a positive order in carbon dioxide and a first-order dependence on the stannane. The initial rates were lower with the deca-tin complex than with the stannane precursor, but the turnover numbers (TONs) were higher. Water, the co-product of the reaction, was found to reversibly poison the active centers. Its in situ trapping had a beneficial effect. This study provides new mechanistic clues as to the reactive species and DMC formation. Further kinetics work is in progress to determine the rate-limiting step(s) at the initial stage of the reaction for more active catalyst design.     

The Effect of Sulphur and Water Treatments on the Performance of Pd/��-Zeolite Diesel Oxidation Catalysts

Sulphur, sulphur-water, and water pretreatments were done to find out the effect of these compounds on a diesel oxidation Pd/??-zeolite catalyst and ??-zeolite washcoat. After pretreatments, the samples were analysed by BET, XRF, TEM-SEM, and XPS. In addition, the activity of fresh and pretreated Pd/??-zeolite catalysts was studied utilizing the by Gasmet FT-IR in production gas analysis. Sulphur compounds (SO₂ or ?SO₄) were found to have a deactivating effect on the activity of the studied Pd/??-zeolite catalyst.     

Defoliation-induced responses in peroxidases,phenolics, and polyamines in scots pine (Pinus sylvestris L.) needles

Effects of artificial defoliation on defensive needle chemistry in Scots pine (Pinus sylvestris L.) were evaluated with particular emphasis on peroxidases, phenolic compounds, soluble sugars, polyamines, and foliar nitrogen levels. The study was carried out on a nutrient-poor Scots pine stand with 8- to 25-year-old trees. Defoliation treatment consisted of repeated defoliation in two successive years with respective control trees. Defoliation was done before needle flushing by removing all mature needles. Guaiacol peroxidase activity increased in the needles after the first defoliation. The difference between treatments diminished towards autumn, and disappeared before the second defoliation in the next summer. After the second defoliation, the activities showed a similar trend. Apparently, peroxidases are involved in inducible chemical changes and recovery reactions that occur in the intact needles shortly after defoliation. After the second defoliation, total nitrogen concentration in the current year needles was about 20% lower, and free putrescine (a polyamine) concentration was 40% lower in the defoliated trees than in control needles. These changes indicate a loss of nitrogen due to defoliation. Specific phenolic compounds such as quercitrin, (+)-catechin, and two catechin derivatives increased in current year needles in response to defoliation. Accumulation of starch and sucrose in the current year needles of repeatedly defoliated trees may imply decreased assimilate transport. The results are indicative that changes in needle phytochemistry in response to defoliation accompany changes in needle nitrogen metabolism.     

Boron Fertilization Enhances the Induced Defense of Silver Birch

Boron (B) deficiency is a common micronutrient deficiency that has been reported to affect the phenolic metabolism of plants. Thus, it may play a role in defense against herbivorous animals. However, the role of B in a plant’s resistance to herbivores has not received any particular attention from researchers. In this study, we tested the effects of B nutrition 1) on the biochemical and mechanical defenses of birches and the growth of seedlings, and 2) the resistance of seedlings to larvae of the autumnal moth, Epirrita autumnata. Boron fertilization improved the resistance of birch, which was shown as reduced pupal weight of the herbivore. However, B fertilized trees suffered from heavier defoliation than unfertilized ones due to compensation feeding of larvae. The growth of the seedlings was diminished, and several biochemical changes occurred in leaves of herbivore seedlings, and B also played a role in these changes. Polyphenoloxidases (PPOs) and peroxidases (PODs) and their substrates, chlorogenic acids, were induced by herbivory in B fertilized seedlings but not in unfertilized seedlings. The lower pupal weights and increased consumption of the herbivores were probably linked to the plants’ phenoloxidase-mediated production of reactive quinones, which decrease the nutritive value. Herbivory upon new stems led to an increase in the number of resin glands that provide defense against mammalian herbivores. Herbivory also had a substantially negative effect on B concentration in leaves of B fertilized seedlings. We postulate that B nutrition of trees may play a significant role in the induced defense of birches.     

Surface properties and moisture behaviour of pine and heat-treated spruce modified with alkoxysilanes by sol–gel process

The surface morphology and moisture behaviour of pine (Pinus sylvestris) sapwood and heat-treated spruce (Picea abies) deposited with two types of silane-based sol–gel coatings were studied by atomic force microscopy (AFM) and water contact angle measurement. The chemical composition and distribution of sol–gel coatings on wood surfaces were investigated by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The AFM images revealed that the sol–gel coatings applied by spreading covered the fine structure of the wood substrates. The surface roughness analysis of the AFM topographical images indicated that the sol–gel coatings, especially the one with short aliphatic chain, had a tendency to smooth the wood surface. The XPS results confirmed that the sol–gel coatings had successfully deposited onto pine sapwood and heat-treated spruce changing their surface chemistries. ToF-SIMS images showing Si ion distribution on treated surfaces revealed that the coatings fully covered pine sapwood surfaces. The thin coating layers formed on heat-treated spruce surfaces followed the original wood surface structure. The contact angle measurements indicated that the water repellent properties of both pine and heat-treated spruce were improved to certain extent by the sol–gel coatings.