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The European Alpha-1 Research Collaboration (EARCO) will promote international research in alpha-1 antitrypsin deficiencyhttp://ow.ly/DWwg30nwCj4

Contains fulltext : 48199.pdf (Publisher’s version ) (Closed access) The beneficial effect of porosity reduction on the fatigue life of bone cement has been demonstrated in numerous experimental studies. Clinically, however, it seems that the beneficial effect of porosity reduction of cement around total hip replacement components can only be found in large follow-up studies. Little is known about the actual mechanical effect of a pore on fatigue crack formation in cement mantles. We studied the effect of pores on the crack formation process in a finite element model of a transverse slice of a total hip reconstruction. We created models with a single large pore and models with multiple pores at levels of 2, 4, and 9%. The models were cyclically torque-loaded, causing macrocracks to appear in the cement mantle. In all models, we found that pores acted as microcrack initiators. However, pores could have both a detrimental and a beneficial effect on the macrocrack propagation in the cement mantle. Both effects were seen in the models with a single large pore and in the models with multiple pores. Pores would either accelerate, deviate, or decelerate the macrocrack propagation in the cement mantle. The effect of the pores depended on the location of the pores with respect to the stress intensities in the model, but was independent of the pore size or the level of porosity. The results may explain why the beneficial effect of vacuum mixing is difficult to demonstrate clinically. Stress intensities that are present in a cement mantle in an in vivo situation may overshadow the detrimental effect of a pore, while the beneficial effect may become more pronounced.

BACKGROUND: Genetic factors play a role in chronic obstructive pulmonary disease (COPD) but are poorly understood. A number of candidate genes have been proposed on the basis of the pathogenesis of COPD. These include the matrix metalloproteinase (MMP) genes which play a role in tissue remodelling and fit in with the protease--antiprotease imbalance theory for the cause of COPD. Previous genetic studies of MMPs in COPD have had inadequate coverage of the genes, and have reported conflicting associations of both single nucleotide polymorphisms (SNPs) and SNP haplotypes, plausibly due to under-powered studies. METHODS: To address these issues we genotyped 26 SNPs, providing comprehensive coverage of reported SNP variation, in MMPs- 1, 9 and 12 from 977 COPD patients and 876 non-diseased smokers of European descent and evaluated their association with disease singly and in haplotype combinations. We used logistic regression to adjust for age, gender, centre and smoking history. RESULTS: Haplotypes of two SNPs in MMP-12 (rs652438 and rs2276109), showed an association with severe/very severe disease, corresponding to GOLD Stages III and IV. CONCLUSIONS: Those with the common A-A haplotype for these two SNPs were at greater risk of developing severe/very severe disease (p = 0.0039) while possession of the minor G variants at either SNP locus had a protective effect (adjusted odds ratio of 0.76; 95% CI 0.61 - 0.94). The A-A haplotype was also associated with significantly lower predicted FEV1 (42.62% versus 44.79%; p = 0.0129). This implicates haplotypes of MMP-12 as modifiers of disease severity.

Contains fulltext : 47857.pdf (Publisher’s version ) (Closed access) The Capital Hip implant was a Charnley-based system which included a flanged and a roundback stem, both of which were available in stainless steel and titanium. The system was withdrawn from the market because of its inferior performance. However, all four of the designs did not produce poor rates of survival. Using a simulated-based, finite-element analysis, we have analysed the Capital Hip system. Our aim was to investigate whether our simulation was able to detect differences which could account for the varying survival between the Capital Hip designs, thereby further validating the simulation. We created finite-element models of reconstructions with the flanged and roundback Capital Hips. A loading history was applied representing normal walking and stair-climbing, while we monitored the formation of fatigue cracks in the cement. Corresponding to the clinical findings, our simulation was able to detect the negative effects of the titanium material and the flanged design in the Capital Hip system. Although improvements could be made by including the effect of the roughness of the surface of the stem, our study increased the value of the model as a predictive tool for determining failure of an implant.

Item does not contain fulltext Prosthetic migration has been identified as a marker for future revision of cemented total hip reconstructions. This could be tested at a pre-clinical stage with dynamic loading experiments. The purpose of this study was to assess the effects of resting periods, which are a considerable part of the daily activity cycle, on the migration characteristics of femoral cemented stems. Ten polished Exeter stems were implanted in composite femurs and loaded either with a continuous load or a discontinuous load. Continuous loading involved 345,600 loading cycles at 1 Hz, whereas the discontinuous loading involved loading at 1 Hz for 2.5 hours and a resting period of 21.5 hours for a period of four days. Hence, a total of 36,000 loading cycles were applied to these reconstructions. The subsidence patterns of the prostheses were considerably affected by the resting periods. The prostheses exhibited a step-wise migration pattern with migration steps of about 50 microns after every resting period, whereas the continuously loaded prostheses showed a more gradual migration pattern. The final subsidence of the specimens when loaded with resting periods was significantly less than the subsidence measured without resting periods. However, these specimens were loaded with fewer loading cycles. If this was taken into account, the discontinuously loaded specimens had a four fold higher average migration per loading cycle than the specimens that were loaded continuously. In conclusion, the resting periods had a considerable effect on the migration patterns, which should be realized when these stems are analyzed with pre-clinical tests.

Onderzoek uitgevoerd in opdracht van de Directie Coordinatie Emancipatiebeleid van het Ministerie van Sociale zaken en Werkgelegenheid.Het onderzoek sluit aan bij een longitudinaal onderzoek (JOA of Jongeren en Arbeid) waarbij jongeren vanaf 1988 gevolgd werden bij hun keuzeprocessen op het gebied van opleiding, arbeid, relatievorming en zorgtaken. In dit onderzoek zijn de (toen inmiddels) 27-31- jarigen uitvoerig geinterviewd over hun arbeid-zorg trajecten, over de arbeid-zorgverdeling tussen partners en onderhandelingen hierover, over de invloed van verdiensituaties (inkomen, arbeidstijden enz.) op het al dan niet gebruik maken van kinderopvang en ouderschapsverlof. In het rapport wordt onderscheid gemaakt in de taakverdelingen van standaardbiografisch en keuzebiografisch georienteerde ouders. De keuze voor een ongelijke arbeid- zorgverdeling blijkt vaak al gemaakt te zijn voordat vrouwen zwanger zijn van hun eerste kind. (Verwachtingen over) de kwaliteit van de levensstandaard en levenswijze, kosten voor levensonderhoud, ongelijke verdiensituaties van mannen en vrouwen dragen eraan bij dat vaders - ondanks eerdere opvattingen over gelijke verdeling van arbeid en zorg -fulltime werken. Ervaringen met lange wachtlijsten, geringe flexibiliteit en te hoge kosten voor kinderopvang, en het ontbreken van verlofregelingen c.q. slechte voorlichting hierover ontmoedigen moeders om zorg te combineren met ambitieus werk. Het rapport bevat casestudies over keuzes die de verschillende groepen ouders tussen hun 16e en 31e levensjaar maken en bijstellen.

Item does not contain fulltext PURPOSE: This article describes the development of a three-dimensional finite element model of a premolar based on a microscale computed tomographic (CT) data-acquisition technique. The development of the model is part of a project studying the optimal design and geometry of adhesive tooth-colored cusp-replacing restorations. MATERIALS AND METHODS: The premolar was digitized with a micro CT scanner with a resolution of 13 microns. Surface contours were fitted to the various materials, after which a 3-D finite element mesh was constructed to the contours. To demonstrate the potential use of the resulting model, it was applied to a cusp-replacing resin composite restoration. RESULTS: The stress patterns generated in the composite material were truly 3-D. Stress concentrations were found at the surface where the load was applied and in the vicinity of the dentin-composite bonding surface, where the interface had its complex geometry. CONCLUSION: The described procedure is an easy method to produce a highly detailed 3-D finite element model of a premolar with an adhesive cusp-replacing restoration.

Alpha1-antitrypsin (α1-AT) deficiency is a common genetic disorder, with homozygous genotype Z as the most relevant deficient type for clinicians. In some parts of Europe, this phenotype is as prevalent as cystic fibrosis and for both disorders there is presently no cure for the disease, which has implications for genetic testing in many countries. In 2003, the European Respiratory Society and American Thoracic Society published a joint statement of standards for diagnosis and management of individuals with α1-AT deficiency 1. Recently, a full chapter on genetic testing addressed the pros and cons of this issue. In pulmonary practice, diagnostic testing of a single case with onset of symptoms related to chronic obstructive pulmonary disease (COPD) at early age is most frequently performed. Predispositional detection of the related family of the newly detected case is already more questionable and relates to the care that doctors can provide to cases detected by family screening. Case detection is somewhat different from screening, as screening activity is usually employed for subjects with no symptoms of disease. Public health authorities often only allow for (neonatal) screening if it …

During cardiopulmonary exercise testing (CPET) compromised pulmonary vasculature in patients with systemic sclerosis (SSc) may lead to increases in pulmonary arterial pressures (PAP) and decreased oxygen uptake. We hypothesised that this may lead into a disproportional heart rate (HR) increase with a corresponding V'O₂/HR breakpoint and relates to systolic PAP at rest.In a prospective design we evaluated V'O₂/HR slopes for breakpoints. To understand its physiological meaning, we evaluated V'O₂/HR and V'O₂/mPAP slopes for breakpoints in a historic data set of SSc patients, in which CPET and right heart catheterisation was performed simultaneously. V'O₂/HR slopes with a peak oxygen uptake outside the normal range were defined as pathologic.A breakpoint occurred in both V'O₂/mPAP and V'O₂/HR slope in 16/34 patients in the historic dataset and occurred in the V'O₂/mPAP slope at a lower V'O₂in 15 patients. In the prospective dataset, 73/121 patients showed a V'O₂/HR breakpoint and achieved a significantly lower peak oxygen uptake compared to 48/121 patients without a V'O2/HR breakpoint (p=0.036). Mean systolic PAP in 41/121 patients with a pathologic V'O₂/HR slope differed significantly from patients without a pathologic V'O₂/HR slope (p=0.027). In 27/121 patients with a systolic PAP35 mmHg a pathologic V'O₂/HR slope was observed.SSc patients with a V'O₂/HR breakpoint are characterised by a decreased oxygen uptake, likely caused by sudden PAP increases during exercise. Importantly, in patients with normal resting SPAP pathologic V'O₂/HR slopes were observed. This suggests that these patients are at risk for developing pulmonary hypertension.

Contains fulltext : 74397.pdf (Publisher’s version ) (Open Access) RU Radboud Universiteit Nijmegen, 14 april 2009 Promotor : Verdonschot, N.J.J. Co-promotores : Stolk, J., Mann, K.A. 153 p.

Item does not contain fulltext The long-term fixation of cemented femoral components may be jeopardised by the presence of a fibrous tissue layer at the bone-cement interface. This study used both experimental and finite element (FE) methods to investigate the load transfer characteristics of two types of cemented hip replacements (Lubinus SPII and Muller-Curved) with a fibrous tissue layer.The experimental part investigated six stems of each type, where these were implanted in composite femurs with a specially selected silicone elastomer modelling the soft interfacial layer. Two fibrous tissue conditions were examined: a layer covering the full cement mantle, representing a revision condition; and a layer covering the proximal portion of the cement mantle, representing a non-revised implant with partial debonding and fibrous tissue formation. The FE method was used to model the full fibrous tissue layer condition, for both implants. The layer was modelled as a homogeneous, linearly isotropic material. A cross-comparison was performed of the experimental and FE findings.Agreement between experimental and FE models was verified to be within 15%. Varying the stiffness parameter of the FE soft tissue layer had little influence on the cortical bone strains, though had considerable effect on the cement strains. Stress shielding occurred for both stems under both fibrous tissue conditions, with the greatest reduction around the calcar. However, the cortical bone strains were generally larger than those for the equivalent well-fixed stems. The fibrous tissue layer was not found to increase the general strain pattern of the cement mantle, though localised regions of high stress were detected.

The birth of a child who has a handicap is a great disappointment for parents. Their baby does not meet the expectations that they developed during the past nine months. What they value in their lives and parenthood has been tossed in the air. Parents may face emotional problems and difficulties in the upbringing of their child with mental retardation. They may also be confronted with fundamental questions regarding the meaning of life of their child and of their own lives as parents.