All-polyethylene tibial components in TKA in rheumatoid arthritis: a 25-year follow-up study

PURPOSE: There is renewed interest in the all-polyethylene tibial component in total knee arthroplasty (TKA). Long-term results of this prosthesis in rheumatoid arthritis (RA) patients, however, are limited. Therefore, we studied 104 primary cemented all-polyethylene tibial TKA in 80 consecutive RA patients for up to 25 years to determine the long-term survival of all-polyethylene tibial components in patients suffering from end stage RA. METHODS: We estimated revision rates according the revision rate per 100 observed component years used in national joint registries. Kaplan-Meier was used to estimate survival curves. RESULTS: During the 25-year follow-up, three revisions for tibial component loosening were performed. The mean revision rate of all-polyethylene tibial components with revision for aseptic loosening as the endpoint was 0.09 per 100 observed component years. This corresponds to a revision rate of 0.9% after ten years and 2.25% after 25 years. Survivorship according to Kaplan-Meier was 100% at ten years and 87.5% at 25 years [95% confidence interval (CI) 64.6-100)]. CONCLUSION: This study shows good long-term results of all-polyethylene tibial TKA in patients with RA. RA patients with multiple-joint inflammation may be less physically active than osteoarthritis patients, resulting in a lower demand on the prosthesis, and these patients may, indeed, be good candidates for all-polyethylene tibial TKA. Our results suggest that all-polyethylene tibial TKA could be a successful and cost-saving treatment for end-stage knee arthritis in RA patients.Optimising joint reconstruction management in arthritis and bone tumour patient

Beschermde gebieden Noordzee: noodzaak en mogelijkheden

This study on protected areas in the North Sea has been carried out for the Directorate of Nature, Environment and Fauna Management of the Ministry of Agriculture, Nature Management and Fisheries. It is part of a project (project number 22) of the Nature Policy Plan of this Ministry. The objective of the study, as defined by the Directorate of Nature, Environment and Fauna Management, is to review the necessity and feasibility of the designation of protected areas in the Dutch sector of the North Sea as a contribution to the conservation and, where possible, rehabilitation of a natural diversity of ecologically valuable areas with their specific communities and characteristic species. The objectives for the designation of marine protected areas are given in chapter 2 of the report: To preserve, rehabilitate and develop natural values in the Dutch sector of the North Sea by limiting the effects of those human activities that cause detectable changes in the North Sea ecosystem . To protect groups of animals which are an integral part of the natural values of the Dutch sector of the North Sea and whose existence or 'normal' functioning is currently threatened within this part of the North Sea. The study only addresses those human activities which can be controlled within the boundaries of the Dutch sector of the North Sea itself: fisheries, off-shore mining, sand and gravel extraction, military activities, shipping, pipelines and telecommunication cables. Pollution from land-based sources, atmospheric deposition, dumping and calamities have therefore not been considered in this report. Chapter 3 contains a description of the North Sea ecosystem (plankton, benthos, fish, seabirds and marine mammals). An effort was made to develop an ecological zoning for each of these groups of animals (see map on back cover). In many cases it has been possible to present relevant (a)biotic parameters. These parameters have played an important role in the final choice of protected areas. The distribution of plankton is to a large extent related to the position of water-bodies in the Dutch sector of the North Sea. The following areas can be identified: coastal water, southern North Sea, central North Sea and the Frisian Front area. The distribution of micro-, meio- and macrobenthos is largely determined by sediment types (sand, mud, gravel, stones). By and large, the following clusters can be identified with respect to infauna (macrobenthos living in the sediments) and epifauna (macrobenthos living on the seafloor): the Southern Bight including the coastal zone, Oystergrounds, Dogger Bank, the area north of the Dogger Bank, the Frisian Front area and the Klaverbank. The distribution of fish is not only determined by such factors as temperature, food, sediment type and water depth, but also by the presence of spawning and nursery areas and the location of migratory routes. With respect to seabirds, four different areas can be identified: the coastal zone, the Southern Bight, the Frisian Front area and the northern part of the Dutch sector of the North Sea. The distribution of seabirds is determined by such factors as the presence of breeding areas, migratory and wintering movements, feeding methods and availability of food. The distribution of marine mammals depends on the species. Porpoises are found both in the northern part of the Dutch sector of the North Sea and in the coastal zone north of the Frisian Islands. Dolphins are rarely seen in coastal waters. The effects of human activities in the Dutch sector of the North Sea are discussed in chapter 4 and can be summarized as follows. Fishery is a frequent large-scale activity which throughout the Dutch sector of the North Sea has resulted in considerable changes within the ecosystem. There is hardly any place where benthic communities can develop undisturbed. At least 10 benthic species have disappeared or their numbers have decreased substantially. The spawning stocks and stability of many fish stocks have decreased substantially as well. Some bird species, however, have increased in numbers. In addition, intensive fisheries have possibly contributed to the decline of sea mammal populations. Offshore mining can, as a result of discharges of cuttings contaminated with oil-based muds (OBM), result in long-term local effects on the benthic system. Effects of water-based muds (WBM) cannot be ruled out, but will be found in smaller areas over a shorter period of time than the effects of OBM. Effects of discharges of production water have not been observed but could occur locally with effects on plankton, fish and birds. It seems unlikely that acoustic disturbance by offshore mining (including seismic surveys) should affect sea mammals which are more that 100 m away from the installation producing the disturbance. Some disturbance may occur as a result of ship and helicopter movements associated with offshore mining. Sand and gravel extraction and the laying of pipelines and telecommunication cables will result in local effects on the benthic system. The destruction of shellfish beds in the coastal zone by sand or gravel extraction might have long-term effects on scoters. It is not possible to quantify the effects of substances introduced into the marine environment by shipping and military activities. Noise produced by such activities may affect communication between sea mammals and behaviour of seabirds. There may be a recovery of those populations which are affected by fisheries. discharges from mining installations, sand and gravel extraction and the laying of pipelines and telecommunication cables after termination of these activities in certain parts of the Dutch sector of the North Sea. This would contribute to the recovery and conservation of these populations in the North Sea in general (see chapter 5). In general, recovery of communities may take 1 to 20 years (benthos and fish), 5 to 50 years (for seabirds) and 20 to more then 50 years (for sea mammals). Recovery will be impossible if gravel extraction has resulted in the removal of the entire layer of gravel on the seafloor. Chapters 6 and 7 give the objectives and related criteria which are used for the designation and the selection of areas which qualify for a protected status. The first criterion addresses the extent to which specific activities have developed into a threat to the existence or normal functioning of groups of animals or species in the Dutch sector of the North Sea. Fishery activities result in large-scale effects on a large number of ecological groups (benthos, fish, seabirds, marine mammals) in the Dutch sector of the North Sea. Discharges of cuttings contaminated with OBM result in long-term local benthic effects. Other discharges by offshore mining installations and sand and gravel extraction have local but possibly large-scale effects on benthos in specific relatively small areas such as the Frisian Front area or the Klaverbank. The second criterion addresses the question whether a prohibition or restriction of certain human activities in specific areas would reduce the threat to those groups of animals or species which were identified through the application of the first criterion. Alternatives for prohibitive or restrictive measures are also discussed. The designation of protected areas where certain activities are prohibited or restricted has the potential to contribute to the conservation or recovery of threatened species. In a number of cases there is no alternative other than the designation of protected areas. This is true of the threat to the benthos and fish which is caused by fisheries activities in the (Dutch sector of the) North Sea, and, in specific relatively small areas, it is also true of the threat to benthos caused by discharges from offshore mining installations and by sand and gravel extraction. The third criterion is used for identifying the areas most suitable for a protected Status on the basis of the ecology of groups of animals or species which need protection. Ecological criteria such as diversity, representativeness. integrity and vulnerability have been used. The application of ecological criteria results in the general conclusion that, within the Dutch sector of the North Sea, the following types of areas qualify for a protected status: a sandy area, a muddy area, an area with frontal characteristics and a gravel area. A protected area should contain coastal waters and an adequate depth gradient. An unbroken area which contains areas of all types would be the most effective option for protection. For the protection of benthos species with a limited migration, areas of circa one hundred square kilometers each should be sufficient; for fish species with an extensive migration pattern it would be necessary to protect a large part of the whole North Sea. It is concluded that for the protection of those species which are most characteristic of the Dutch sector of the North Sea it is necessary to protect an area with a total surface of some 31 ICES blocks (each some 60 x 60 square kilometers). The fourth criterion addresses the question whether there are adequate legal instruments to ensure effective protection of the selected areas. On the basis of existing legal instruments it is, in principle, possible to protect these areas. However; there are certain problems associated with measures which are required with respect to fisheries, gravel extraction and offshore mining. On the basis of the above criteria it is concluded that two areas within the Dutch sector of the North Sea qualify for a protected status: 1. An area directly northwest of the Frisian Islands (see Figs A and B). In this unbroken area of some 10,000 square kilometers it will be possible to protect a combination of different types of benthic communities (coastal waters, sandy bottoms, the Frisian Front area, muddy areas and restricted areas with gravel and stones). The area will also have an adequate depth gradient. The proposed area contains important spawning and nursery areas for fish (including squid) and habitats of many (non-commercial) fish species. Seasonal migratory routes to and from the Wadden Sea are concentrated in this area. Relatively large numbers of porpoises as well as dolphins and seabirds occur in this area. Protection of this area also strengthens the functioning of the Wadden Sea as a nursery area and supports the recolonisation of benthos in the Wadden Sea after, for instance, severe winters. There are two alternative options for the exact location of the area to be protected. The first alternative (Fig. A) has been chosen especially with an emphasis on conservation and recovery of the diversity of communities in the Dutch sector of the North Sea. The second alternative (Fig. B) more closely relates to existing measures regarding fisheries. The proportion of muddy areas is very low in this alternative. An expansion of the proposed area in an easterly direction could be considered only if it connected the area with similar protected areas in the German sector of the North Sea. An expansion of the proposed area in a southerly direction would more closely relate to the ecological interests of the Wadden Sea. The following protective measures are proposed for this area: The area will be closed for all types of fisheries throughout the year; Discharges from offshore mining installations which contain oil will be prevented (OBM) or minimized (production water); Additional area-specific protective measures with respect to offshore mining, shipping, military activities, sand extraction, dumping and the laying of pipelines can be considered whenever the situation in this area calls for such measures. Such measures should also be considered for areas to be used as reference areas for scientific research; The application of policies resulting from the implementation of international conventions with respect to conservation (the EC Bird Directive, the Conventions of Bonn, Berne and Ramsar, the proposed EC Habitat Directive). 2. Klaverbank (see Figs A and B). The Klaverbank, the only gravel area of importance in the Dutch sector of the North Sea, has a still relatively undisturbed benthic fauna which is specific to this type of area. The Klaverbank (approximately 800 square kilometers) should be given a protected status under which gravel extraction is prohibited. and discharges from offshore mining installations which contain oil will be prevented (OBM) or minimized (production water). Fisheries too should be prohibited but the limited size of this area rules out effective implementation and enforcement of such a measure. It is therefore advisable to develop proposals in cooperation with the United Kingdom for the designation of a protected area in the UK sector of the North Sea which should contain a large gravel area and possibly also the Klaverbank. If a decision is taken to protect these areas, it will be necessary to develop a management plan. Chapter 8 gives a possible outline for such a management plan, including certain relevant issues. Firstly, it will be necessary to define objectives for these specific areas in addition to the objectives already defined for the designation of protected areas in general. Secondly, it will be necessary to attune measures for the management of these areas to the objectives of their protection. A management plan will also have to address the organizational structure required for effective management of these areas. Arrangements for adequate enforcement and effective control of measures taken are also necessary. Programmes for scientific research will have to be developed

Low-temperature structural model of hcp solid C70_{70}

We report intermolecular potential-energy calculations for solid C_${70}$ and determine the optimum static orientations of the molecules at low temperature; we find them to be consistent with the monoclinic structural model proposed by us in an earlier report [Solid State Commun. {\bf 105), 247 (1998)]. This model indicates that the C_5 axis of the molecule is tilted by an angle $\approx$18^o from the monoclinic b axis in contrast with the molecular orientation proposed by Verheijen {\it et al.} [J. Chem. Phys. {\bf 166}, 287 (1992)] where the C_5 axis is parallel to the monoclinic b axis. In this calculation we have incorporated the effective bond charge Coulomb potential together with the Lennard-Jones potential between the molecule at the origin of the monoclinic unit cell and its six nearest neighbours, three above and three below. The minimum energy configuration for the molecular orientations turns out to be at $\theta$=18^o, $\phi$=8^o, and $\psi$=5^o, where $\theta$, $\phi$, and $\psi$ define the molecular orientations.Comment: ReVTeX (4 pages) + 2 PostScript figure

Minor influence of humeral component size on torsional stiffness of the Souter-Strathclyde total elbow prosthesis

The use of Souter-Strathclyde total elbow prostheses is a well-studied replacement therapy for reconstruction of the elbow, but loosening of the humeral component is still of concern at long-term follow-up. In this study we looked at the effect of humeral component size and bone mineral density with respect to the bone size, torsional stiffness and torque to failure in cadaveric bones. Fourteen cadaveric humeri were available for testing purposes and four different humeral component size categories were used. First, we calculated the bone quality using dual-energy X-ray absorptiometry (DEXA). The torsional stiffness of the prosthetic humeri was measured during two mechanical tests: Firstly, the applied torque was recorded during a torsion fatigue test. The change of torsional stiffness between the tenth and last cycle was calculated. Secondly, a simple torsion test was performed and the torque to failure was recorded. No significant differences in outcome were seen between sizes of humeral components, even after correction for the bone size. Torsional stiffness and torque to failure were significantly correlated with bone mineral density and not with component size. In conclusion, bone quality seems to be a major eminent factor in the fixation of the humeral component in elbow replacement surgery

Environmental consciousness in the Netherlands

Contains fulltext : 3328.pdf (publisher's version ) (Open Access

Neuroinflammation, Mast Cells, and Glia: Dangerous Liaisons

The perspective of neuroinflammation as an epiphenomenon following neuron damage is being replaced by the awareness of glia and their importance in neural functions and disorders. Systemic inflammation generates signals that communicate with the brain and leads to changes in metabolism and behavior, with microglia assuming a pro-inflammatory phenotype. Identification of potential peripheral-to-central cellular links is thus a critical step in designing effective therapeutics. Mast cells may fulfill such a role. These resident immune cells are found close to and within peripheral nerves and in brain parenchyma/meninges, where they exercise a key role in orchestrating the inflammatory process from initiation through chronic activation. Mast cells and glia engage in crosstalk that contributes to accelerate disease progression; such interactions become exaggerated with aging and increased cell sensitivity to stress. Emerging evidence for oligodendrocytes, independent of myelin and support of axonal integrity, points to their having strong immune functions, innate immune receptor expression, and production/response to chemokines and cytokines that modulate immune responses in the central nervous system while engaging in crosstalk with microglia and astrocytes. In this review, we summarize the findings related to our understanding of the biology and cellular signaling mechanisms of neuroinflammation, with emphasis on mast cell-glia interactions

Contralateral hip fractures and other osteoporosis-related fractures in hip fracture patients: Incidence and risk factors. An observational cohort study of 1,229 patients

Purpose: To report risk factors, 1-year and overall risk for a contralateral hip and other osteoporosis-related fractures in a hip fracture population. Methods: An observational study on 1,229 consecutive patients of 50 years and older, who sustained a hip fracture between January 2005 and June 2009. Fractures were scored retrospectively for 2005-2008 and prospectively for 2008-2009. Rates of a contralateral hip and other osteoporosis- related fractures were compared between patients with and without a history of a fracture. Previous fractures, gender, age and ASA classification were analysed as possible risk factors. Results: The absolute risk for a contralateral hip fracture was 13.8 %, for one or more osteoporosis-related fracture( s) 28.6 %. First-, second- and third-year risk for a second hip fracture was 2, 1 and 0 %. Median (IQR) interval between both hip fractures was 18.5 (26.6) months. One-year incidence of other fractures was 6 %. Only age was a risk factor for a contralateral hip fracture, hazard ratio (HR) 1.02 (1.006-1.042, p = 0.008). Patients with a history of a fracture (33.1 %) did not have a higher incidence of fractures during follow-up (16.7 %) than patients without fractures in their history (14 %). HR for a contralateral hip fracture for the fracture versus the non-fracture group was 1.29 (0.75-2.23, p = 0.360). Conclusion: The absolute risk of a contralateral hip fracture after a hip fracture is 13.8 %, the 1-year risk was 2 %, with a short interval between the 2 hip fractures. Age was a risk factor for sustaining a contralateral hip fracture; a fracture in history was not

Making PDFs Accessible for Visually Impaired Users (and Findable for Everybody Else)

We treat documents released under the Dutch Freedom of Information Act as FAIR scientific data and find that they are not findable nor accessible, due to text malformations caused by redaction software. Our aim is to repair these documents. We propose a simple but strong heuristic for detecting wrongly OCRed text segments, and we then repair only these OCR mistakes by prompting a large language model. This makes the documents better findable through full text search, but the repaired PDFs do still not adhere to accessibility standards. Converting them into HTML documents, keeping all essential layout and markup, makes them not only accessible to the visually impaired, but also reduces their size by up to two orders of magnitude. The costs of this way of repairing are roughly one dollar for the 17K pages in our corpus, which is very little compared to the large gains in information quality.<br/

The Exeter femoral stem continues to migrate during its first decade after implantation: 10–12 years of follow-up with radiostereometric analysis (RSA)

Optimising joint reconstruction management in arthritis and bone tumour patient

A Comprehensive Approach to Identify Reliable Reference Gene Candidates to Investigate the Link between Alcoholism and Endocrinology in Sprague-Dawley Rats

Gender and hormonal differences are often correlated with alcohol dependence and related complications like addiction and breast cancer. Estrogen (E2) is an important sex hormone because it serves as a key protein involved in organism level signaling pathways. Alcoholism has been reported to affect estrogen receptor signaling; however, identifying the players involved in such multi-faceted syndrome is complex and requires an interdisciplinary approach. In many situations, preliminary investigations included a straight forward, yet informative biotechniques such as gene expression analyses using quantitative real time PCR (qRT-PCR). The validity of qRT-PCR-based conclusions is affected by the choice of reliable internal controls. With this in mind, we compiled a list of 15 commonly used housekeeping genes (HKGs) as potential reference gene candidates in rat biological models. A comprehensive comparison among 5 statistical approaches (geNorm, dCt method, NormFinder, BestKeeper, and RefFinder) was performed to identify the minimal number as well the most stable reference genes required for reliable normalization in experimental rat groups that comprised sham operated (SO), ovariectomized rats in the absence (OVX) or presence of E2 (OVXE2). These rat groups were subdivided into subgroups that received alcohol in liquid diet or isocalroic control liquid diet for 12 weeks. Our results showed that U87, 5S rRNA, GAPDH, and U5a were the most reliable gene candidates for reference genes in heart and brain tissue. However, different gene stability ranking was specific for each tissue input combination. The present preliminary findings highlight the variability in reference gene rankings across different experimental conditions and analytic methods and constitute a fundamental step for gene expression assays