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Selected AbstractsHealth outcomes associated with methamphetamine use among young people: a systematic reviewADDICTION, Issue 6 2010Brandon D. L. Marshall ABSTRACT Objectives Methamphetamine (MA) use among young people is of significant social, economic and public health concern to affected communities and policy makers. While responses have focused upon various perceived severe harms of MA use, effective public health interventions require a strong scientific evidence base. Methods We conducted a systematic review to identify scientific studies investigating health outcomes associated with MA use among young people aged 10,24 years. The International Classification of Diseases (ICD-10) was used to categorize outcomes and determine the level of evidence for each series of harms. Results We identified 47 eligible studies for review. Consistent associations were observed between MA use and several mental health outcomes, including depression, suicidal ideation and psychosis. Suicide and overdose appear to be significant sources of morbidity and mortality among young MA users. Evidence for a strong association between MA use and increased risk of human immunodeficiency virus (HIV) and other sexually transmitted infections is equivocal. Finally, we identified only weak evidence of an association between MA use and dental diseases among young people. Conclusions Available evidence indicates a consistent relationship between MA use and mental health outcomes (e.g. depression, psychosis) and an increased risk of mortality due to suicide and overdose. We found insufficient evidence of an association between MA use and other previously cited harms, including infectious diseases and dental outcomes. As such, future research of higher methodological quality is required to further investigate possible associations. Current interventions should focus attention upon MA-related health outcomes for which sound scientific evidence is available. [source] Global Regime Formation or Complex Institution Building?INTERNATIONAL STUDIES QUARTERLY, Issue 2 2006The Principled Content of International River Agreements This paper analyzes the principled content of 62 international river agreements for the period 1980,2000. We ask two questions: whether governments are converging on common principles for governing shared river basins and whether the effort to create a global normative framework for shared rivers has shaped the principled content of basin-level international accords. The data reveal a complex process of normative development. A few core principles emanating from global legal efforts have shown significant growth, diffusion and deepening at the basin-specific level. Others are common in basin agreements but show no diffusion or deepening. Still others are weakly represented in the data. If joint articulation of common principles is necessary for regime formation, then there is only weak evidence for a global rivers regime. But the data also reveal normative developments not captured by a regime-theoretic lens: a backlash reinforcing sovereign rights, the emergence of two seemingly conflicting clusters of principles, and an ambiguous relationship between some principles typically thought to be mutually reinforcing. The results show the need to treat principled content as an important dependent variable in the study of cooperation and to view institution building as a dynamic, multi-dimensional and multi-level process. [source] Spatial and genetic structure of host-associated differentiation in the parasitoid Copidosoma gelechiaeJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2009C. R. KOLACZAN Abstract Host-associated differentiation (HAD) appears to be an important driver of diversification in the hyperdiverse phytophagous and parasitoid insects. The gallmaking moth Gnorimoschema gallaesolidaginis has undergone HAD on two sympatric goldenrods (Solidago), and HAD has also been documented in its parasitoid Copidosoma gelechiae, with the intriguing suggestion that differentiation has proceeded independently in multiple populations. We tested this suggestion with analysis of Amplified Fragment Length Polymorphism (AFLP) markers for C. gelechiae collections from the midwestern and northeastern United States and eastern Canada. AFLP data were consistent with the existence of HAD, with between-host FST significant before Bonferroni correction in two of seven sympatric populations. amova analysis strongly rejected a model of HAD with a single historical origin, and thus supported the repeated-HAD hypothesis. Copidosoma gelechiae shows significant host-associated divergence at a number of allozyme loci (Stireman et al., 2006), but only weak evidence via AFLPs for genome-wide differentiation, suggesting that this species is at a very early stage of HAD. [source] Genetic diversity, population structure, effective population size and demographic history of the Finnish wolf populationMOLECULAR ECOLOGY, Issue 6 2006J. ASPI Abstract The Finnish wolf population (Canis lupus) was sampled during three different periods (1996,1998, 1999,2001 and 2002,2004), and 118 individuals were genotyped with 10 microsatellite markers. Large genetic variation was found in the population despite a recent demographic bottleneck. No spatial population subdivision was found even though a significant negative relationship between genetic relatedness and geographic distance suggested isolation by distance. Very few individuals did not belong to the local wolf population as determined by assignment analyses, suggesting a low level of immigration in the population. We used the temporal approach and several statistical methods to estimate the variance effective size of the population. All methods gave similar estimates of effective population size, approximately 40 wolves. These estimates were slightly larger than the estimated census size of breeding individuals. A Bayesian model based on Markov chain Monte Carlo simulations indicated strong evidence for a long-term population decline. These results suggest that the contemporary wolf population size is roughly 8% of its historical size, and that the population decline dates back to late 19th century or early 20th century. Despite an increase of over 50% in the census size of the population during the whole study period, there was only weak evidence that the effective population size during the last period was higher than during the first. This may be caused by increased inbreeding, diminished dispersal within the population, and decreased immigration to the population during the last study period. [source] The Effects of Household Income Volatility on DivorceAMERICAN JOURNAL OF ECONOMICS AND SOCIOLOGY, Issue 3 2010John M. Nunley We extend the literature on the effects of earnings shocks on divorce by identifying separately the effects of transitory and permanent household income shocks and by allowing the shocks to have asymmetric effects across education and racial groups. The econometric evidence suggests negative (positive) transitory household income shocks increase (decrease) the probability of divorce, while there is only weak evidence that positive (negative) permanent household income shocks raise (lower) the probability of divorce. Some differences in the effects of household income shocks on divorce propensities arise for subsamples selected by education and race. [source] Latest news and product developmentsPRESCRIBER, Issue 22 2007Article first published online: 28 DEC 200 Glitazones: benefits outweigh the risks Following a review of the safety of rosiglitazone and pioglitazone, the European Medicines Agency (EMEA) has concluded that their benefits outweigh their risks in the approved indications. The review was prompted by reports of an increased risk of fractures in women and, in patients taking rosiglitazone, ischaemic heart disease. The EMEA concluded that prescribing information for rosiglitazone should now include a warning that, in patients with ischaemic heart disease, it should only be used after careful evaluation of each patient's individual risk, and the combination of rosiglitazone and insulin should only be used in exceptional cases and under close supervision. No change was considered necessary to the prescribing information for pioglitazone. Modern dressings no better? A systematic review has found only weak evidence that modern dressings are better than saline gauze or paraffin gauze for healing acute and chronic wounds (Arch Dermatol 2007;143: 1297-304). The analysis, which included 99 studies, found that only hydrocolloids were demonstrably better than older dressings for healing chronic wounds, and alginates were superior to other modern dressings for debriding necrotic wounds. There was no evidence that modern dressings offered superior overall performance to the older alternatives. Hospital inflation twice primary care level The cost of drugs prescribed in secondary care but dispensed in the community increased by 6.4 per cent in 2006 - twice the rate of inflation in primary care - according to the latest statistics on hospital prescribing in England. The increase follows a reduction in costs in 2005 after the introduction of the new PPRS scheme. Data from The Information Centre (www.ic.nhs.uk) show that hospital medicines make up about 24 per cent of the NHS drugs budget. Secondary care has a consistently better record than primary care in prescribing lower-cost alternatives within therapeutic categories, eg simvastatin and pravastatin among the statins, omeprazole and lansoprazole among PPIs, and ACE inhibitors among drugs acting on the renin angiotensin system. The most expensive drug prescribed by hospital specialists and dispensed in the community is interferon beta. MHRA limits the use of fibrates The Medicines and Healthcare products Regulatory Agency (MHRA) has advised that fibrates should now be reserved for the treatment of isolated severe hypertriglyceridaemia. They should be considered for hypercholesterolaemia only when a statin or other treatment is contraindicated or not tolerated. In the latest Drug Safety Update, the MHRA says there is insufficient evidence of long-term benefits from fibrates, and first-line use is no longer justified because the evidence for the benefits of statins is robust. The MHRA also warns that some breastfeeding infants have increased susceptibility to the adverse effects of codeine taken by their mother, and that St John's wort may affect the hepatic metabolism of any anticonvulsant. Annual zoledronic acid infusion cuts mortality after hip fracture Once-yearly infusion of zoledronic acid (Aclasta) after hip fracture reduces deaths over a two-year period by 28 per cent compared with placebo, US investigators say (N Engl J Med 2007;357:1799-809). The HORIZON Recurrent Fracture Trial randomised 2127 men and women (mean age 75) within 90 days of surgery for hip fracture to zoledronic acid 5mg yearly or placebo. Mortality over 1.9 years of follow-up was 9.6 per cent with zoledronic acid and 13.3 per cent with placebo. Zoledronic acid also significantly reduced the rate of any new clinical fractures (by 35 per cent) and new clinical vertebral fractures(by 45 per cent),but the lower rate of hip fracture (2.0 vs 3.5 per cent with placebo) was not statistically significant. Rivastigmine patch for mild to moderate AD Rivastigmine (Exelon) is now available as a transdermal patch for the treatment of mild to moderate Alzheimer's disease. Applied once daily, the patch delivers 9.5mg per 24 hours and, says manufacturer Novartis, is associated with a lower incidence of nausea and vomiting than a comparable oral dose. The patch is available in two strengths: 4.6mg per 24hr is equivalent to oral doses of 3 or 6mg per day, and the 9.5mg per 24hr patch is equivalent to 9 or 12mg per day orally. The recommended dose of the patch is 9.5mg per day; both strengths cost £83.84 for 30 patches. Women more aspirin resistant than men? The cardioprotective effect of low-dose aspirin may be lower in women than men, say Canadian investigators (BMC Medicine 2007;5:29 doi: 10.1186/1741-70155-29). Their meta-analysis of 23 randomised trials involving a total of 113 494 participants found that aspirin significantly reduced the risk of nonfatal but not fatal myocardial infarction (MI). About one-quarter of the variation in its effects on nonfatal MI was accounted for by the sex mix of the trial population. Separating the results by sex showed the reduction in risk with aspirin use was statistically significant in men (relative risk, RR, 0.62) but not in women (RR 0.87). Look after physical health of mentally ill GPs and other primary care workers should take more responsibility for the physical health of their mentally ill patients, say advocacy groups. Mind and Body: Preventing and Improving Physical Health Problems in Patients With Schizophrenia points out that the mental health needs of patients with schizophrenia are met in secondary care, but their physical health needs should be met in primary care. In particular, the metabolic effects of antipsychotics may lead to obesity, diabetes and cardiovascular disease, and weight gain in particular is a frequent reason for nonadherence to treatment. The Mind and Body Manifesto was developed by SANE, The Mental Health Nurses Association, The National Obesity Forum and The Disability Rights Commission and sponsored by Bristol-Myers Squibb Pharmaceuticals Limited and Otsuka Pharmaceuticals (UK) Ltd. Copies are available from elizabeth.green@ ogilvyhealthworld.com. Health eCard costs Some costs quoted in our article on the Health eCard (The Health eCard: the way ahead for medical records?,5 October issue, pages 28-9) have been revised: the card and initial download will cost patients £39.50, and GPs will be entitled to charge patients £10 per annum for subsequent downloads. NICE appraisals of cytokine inhibitors in RA NICE has endorsed the use of the anti-TNF agents adalimumab (Humira), etanercept (Enbrel) and infliximab (Remicade), normally in conjunction with methotrexate, for the treatment of active RA when methotrexate and another DMARD have failed (also see New from NICE below). NICE has provisionally concluded, subject to consultation, that abatacept (Orencia) should not be recommended for the treatment of RA. Boots and BMJ launch health advice site www.askbootshealth.com is a new website providing information about health and medicines for the public produced by Boots using information provided by the BMJ Publishing Group. The website covers many of the topics already available from NHSDirect, with perhaps more information about available treatments. Diabetes care shows small improvement The third National Diabetes Audit in England and Wales has found that more people with diabetes were achieving the targets set by NICE for cholesterol levels, glycaemic control and blood pressure in 2005/06 - but younger patients were doing less well. Overall, the HbA1C target of ,7.5 per cent was achieved in 60 per cent of people with diabetes compared with 58 per cent in 2004/05. However, HbA1C was >9.5 per cent in 30 per cent of children and young people, of whom 9 per cent experienced at least one episode of ketoacidosis. More topics for NICE New topics referred to NICE include clinical guidelines on ovarian cancer, coeliac disease and stable angina, public health guidance on preventing cardiovascular disease, and technology appraisals on insulin detemir (Levemir) for type 1 diabetes, several treatments for cancer and hepatic and haematological disorders, and biological therapies for juvenile arthritis. New from NICE NICE appraisal on anti-TNFs for RA Since NICE published its first appraisal of agents acting against tumour necrosis factor-alpha (anti-TNFs) for the treatment of RA in 2002, the product licences for etanercept (Enbrel) and infliximab (Remicade) have changed and a new agent, adalimumab (Humira), has been introduced. The anti-TNFs act in different ways. Infliximab is a chimeric monoclonal antibody that binds to TNF-alpha, neutralising its activity. Etanercept, a recombinant human TNF-alpha receptor fusion protein, and adalimumab, a human-sequence antibody, both bind to TNF-alpha and block its interaction with cell surface receptors. Adalimumab also modulates some biological responses induced or regulated by TNF-alpha. These agents are recommended for adults with severe active RA (defined as a disease activity score - DAS28 - greater than 5.1) who have already tried two disease-modifying drugs, including methotrexate (if not contraindicated). Prior treatment should have been of at least six months' duration, including two months at the standard dose (unless limited by toxicity). Anti-TNFs should normally be prescribed with methotrexate; when this is not appropriate, etanercept and adalimumab may be prescribed as monotherapy. Treatment with an anti-TNF should be continued beyond six months only if there is an adequate response (defined as an improvement in DAS28 of at least 1.2). Data from the British Rheumatology Society Biologics register show that, after six months, 67 per cent of patients met NICE criteria for an adequate response; this declined to 55 per cent at 18 months. The basic annual cost of treatment is £9295 for adalimumab 40mg on alternate weeks or etanercept 25mg twice weekly; infliximab costs £3777 for a loading dose, then £7553-£8812 depending on dose. Assuming no progression of disability, the incremental costs per QALY (compared with sequential DMARDs) were £30 200 for adalimumab, £24 600 for etanercept and £39 400 for infliximab. There are no direct comparative trials of the anti-TNFs, and their clinical trial findings are not directly comparable. Unless other factors determine treatment choice, NICE therefore recommends the least expensive. If the first anti-TNF is withdrawn within six months due to an adverse event, a second may be tried. [source] Low-Paid Employment and Unemployment Dynamics in Australia,THE ECONOMIC RECORD, Issue 272 2010HIELKE BUDDELMEYER This article uses longitudinal data from the Household, Income and Labour Dynamics in Australia (or HILDA) Survey to examine the extent to which the relatively high rates of transition from low-paid employment into unemployment are the result of disadvantageous personal characteristics or are instead a function of low-paid work itself. Dynamic random effects probit models of the likelihood of unemployment are estimated. After controlling for unobserved heterogeneity and initial conditions, we find that, relative to high-paid employment, low-paid employment is associated with a higher risk of unemployment, but this effect is only significant among women. We also find only weak evidence that low-paid employment is a conduit for repeat unemployment. [source] Browning reactions during storage of low-moisture Australian sultanas: Further evidence for arginine-mediated Maillard reactions during storage, and some effects of vine-shading and harvest dateAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 3 2004DAMIAN FRANK Abstract Sultana grapevines (Vitis Vinifera L. cv. Sultana syn. Thompson Seedless) were subjected to four shading regimes: 50% shading (1), 25% shading (2), fully exposed-top of canopy (3) and beneath canopy (4) and harvested early (21 February) and late (13 March) in the 1996/1997 sultana season. Grapes from each of the eight field-treatment combinations represented a range of maturities (14.4 to 23.50oBrix). Grape samples from each of the treatments were dipped and dried to 18% moisture, with half of each of the sultana samples further reduced in moisture by sunfinishing on plastic sheets in direct sun. These field treatments resulted in sixteen unique dried sultana bulk samples with a range of initial chemico-physical properties; aw (0.481,0.691), skin-polyphenoloxidase (PPO) activity (4.40,9.05 ,mol O2/g.minute) free arginine in skin tissues (1.0,5.10 mg/g) and protein (16.40,27.18 mg/g). Sultanas were stored at 10oC and 30oC in either the presence or absence of oxygen for 10 months, and changes in CIE L*a*b* tristimulus values, hue-angle (hab*) and chroma (Cab*) were monitored. Significant changes in sultana colour occurred in samples stored at 30oC, especially in higher aw non-sunfinished sultanas. Although browning was more intense in the presence of oxygen, significant browning also occurred in the absence of oxygen. Lower concentrations of 5-hydroxy methylfurfural, a key marker of Maillard browning in samples stored at 30oC in the presence of oxygen, indicated that the non-enzymatic reactions were sensitive to oxygen. Changes in the concentration of trans -caftaric acid, the main substrate of grape PPO, were also measured during sultana drying. Storage browning (changes in L*, b*, hab*, Cab*)in dried sultanas could be predicted by regression models using pre-storage aw, free-skin arginine or Kjeldahl protein after 10 months' storage between 10oC and 30oC. Non-enzymatic and Maillard-type reactions (sensitive to both oxygen and aw), made an important contribution to sultana storage browning. We provide only weak evidence that either shaded (immature) or green fruit was more susceptible to storage browning. [source] Latitudinal clines in body size, but not in thermal tolerance or heat-shock cognate 70 (HSC70), in the highly-dispersing intertidal gastropod Littorina keenae (Gastropoda: Littorinidae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2010HYUK JE LEE Natural populations of widely-distributed animals often exhibit clinal variation in phenotypic traits or in allele frequencies of a particular gene over their geographical range. A planktotrophic intertidal snail, Littorina keenae is broadly distributed along the north-eastern Pacific coast through a large latitudinal range (24°50,N,43°18,N). We tested for latitudinal clines in two complex phenotypic traits , thermal tolerance and body size , and one single locus trait , heat shock cognate 70 (HSC70) , in L. keenae along almost its entire geographical range. We found only weak evidence for a latitudinal cline in the thermal tolerance and no evidence for a cline in allele frequencies at HSC70. However, as predicted by Bergmann's rule, we detected a strong latitudinal cline that accounted for 60% of the variance in body size (R2 = 0.598; P < 0.001). In contrast, body size did not significantly affect thermal tolerance. HSC70 showed no genetic differentiation among the populations, supporting our previous mitochondrial gene-based estimate of high gene flow during this snail's free-swimming larval stage. Given that L. keenae experiences panmixia along its species range, the observed size cline may be partially or entirely caused by a phenotypically plastic response to local thermal environments rather than by genetic divergence in body size among populations in response to locally optimizing natural selection. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 494,505. [source] Low population differentiation and high genetic diversity in the invasive species Carduus acanthoides L. (Asteraceae) within its native range in the Czech RepublicBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2009BOHUMIL MANDÁK Colonizing species are predicted to suffer from reductions in genetic diversity during founding events. Although there is no unique mode of reproduction that is characteristic of successful plant colonizers, many of them are predominantly self-fertilizing or apomictic species, and almost all outcrossing colonizers are self-compatible. Carduus acanthoides comprises a species of disturbed habitats with wind-dispersed seeds that colonizes open spaces of various sizes. Population genetic diversity was expressed by assessing patterns of variation at nine putatively neutral allozyme loci within and among 20 natural populations in its native distribution range in the Czech Republic. Overall, C. acanthoides displayed high levels of genetic diversity compared to other herbaceous plants. The percentage of polymorphic loci was 84.5, with values of 2.37, 0.330, and 0.364 for the mean number of alleles per polymorphic locus (A), observed heterozygosity (Ho), and expected heterozygosity (He), respectively. There was only weak evidence of inbreeding within populations (f = 0.097) and very low genetic differentiation among populations (, = 0.085). Analyses of the data provide strong evidence for isolation-by-distance for the whole study area. Even the colonizing species, C. acanthoides, currently supports a substantial amount of allozyme variation at both the species and population levels. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 596,607. [source] Behavioural correlates with hemipenis morphology in New World natricine snakesBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009RICHARD B. KING Copulatory organs (hemipenes) of male snakes vary markedly among species in shape and ornamentation. We suggest that sexual conflict over copulation duration may have shaped the evolution of hemipenis morphology, favouring more elaborate organs in species in which a long duration of copulation is especially beneficial to males, despite the associated costs to females. To test this proposition, we compare mating behaviour between two species of gartersnakes differing in hemipenis morphology. In addition, we review data on copulation duration and hemipenis morphology and relate hemipenis morphology to phylogeny among of New World natricines. As predicted, copulation duration was significantly shorter in the common gartersnake (Thamnophis sirtalis), a species with simple subcylindrical hemipenes, than in the plains gartersnake (Thamnophis radix), a species with more complex, bilobed organs. Furthermore, female T. radix frequently exhibited vigorous body rolls during copulation, a behaviour associated with copulation termination, whereas female T. sirtalis never exhibited this behaviour. Copulations were of shorter duration when female T. radix (but not T. sirtalis) more greatly exceeded males in body size, suggesting that females can more easily disengage from small males. Our review of New World natricines provides only weak evidence for an association between copulation duration and hemipenis morphology. Our mapping of hemipenis morphology onto the New World natricine phylogeny suggests that hemipenis morphology is evolutionarily plastic; both simple and bilobed hemipenes occur in all three major natricine clades, as well as in two of three gartersnake subclades and several sister-species pairs. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 110,120. [source] A tale of two analyses: estimating the consequences of shifts in hexapod diversificationBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2003PETER J. MAYHEW I present a novel descriptive (non-statistical) method to help identify the location and importance of shifts in diversification across a phylogeny. The method first estimates radiation rates across terminal higher taxa and then subjects these rates to a parsimony analysis across the phylogeny. The reconstructions define the magnitude, direction and influence of past shifts in realized diversification rates across nodes. I apply the method to data on the extant hexapod orders. The results indicate that the Coleoptera (beetles) and Diptera (flies) have contributed large upward shifts in diversification tendency, without which, under the model employed, global species richness would be reduced by 20% and 6%, respectively. The origin of Neoptera (insects with wing flexion), identified elsewhere as a significant radiation, may represent a large positive, a large negative or zero influence on current species richness, depending on the assumed phylogeny and parsimony method. The most influential radiations are attributable to the origin of the Eumetabola (insects with complete metamorphosis plus bugs and their relatives) and Pterygota (winged insects), but there is presently only weak evidence that they represent significant shifts in underlying diversification tendency. These analyses support some but not all results of previous phylogenetic analyses and the identity of the most important shift therefore remains elusive. New methodology involving comparisons across multiple taxa is likely to be necessary. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 80, 23,36. [source] Effect of RGD peptide coating of titanium implants on periimplant bone formation in the alveolar crestCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2002An experimental pilot study in dogs Abstract: The aim of the present study was to analyse the effect of organic coating of titanium implants on periimplant bone formation and bone/implant contact. Three types of implants were used: (i) Ti6Al4V implants with polished surface (control 1) (ii) Ti6Al4V implants with collagen coating (control 2) (iii) Ti6Al4V implants with collagen coating and covalently bound RGD peptides. All implants had square cross-sections with an oblique diameter of 4.6 mm and were inserted press fit into trephine burr holes of 4.6 mm in the mandibles of 10 beagle dogs. The implants of five animals each were evaluated after a healing period of 1 month and 3 months, during which sequential fluorochrome labelling of bone formation was performed. Bone formation was evaluated by morphometric measurement of the newly formed bone around the implant and the percentage of implant bone contact. After 1 month there was only little bone/implant contact, varying between 2.6 and 6.7% in the cortical bone and 4.4 and 5.7% in the cancellous bone, with no significant differences between the three types of implants. After 3 months, implants with polished surfaces exhibited 26.5 and 31.2% contact in the cortical and cancellous bone, respectively, while collagen-coated implants had 19.5 and 28.4% bone contact in these areas. Implants with RGD coating showed the highest values with 42.1% and 49.7%, respectively. Differences between the surface types as such were not significant, but the increase in bone/implant contact from 1 to 3 months postoperatively was significant only in the group of RGD-coated implants (P = 0.008 and P = 0.000). The results of this pilot study thus provide only weak evidence that coating of titanium implants with RGD peptides in the present form and dosage may increase periimplant bone formation in the alveolar process. The results therefore require further verification in a modified experimental setting. Résumé Le but de l'étude présente a été d'évaluer l'effet d'un recouvrement organique des implants en titane sur la formation osseuse paro?mplantaire et le contact os/implant. Trois types d'implants ont été utilisés: 1) implants Ti6AI4V avec surface polie (contrôle 1), 2) implants Ti6AI4V avec recouvrement de collagène (contrôle 2), 3) implants Ti6aI4V avec recouvrement de collagène et des peptides RGD accrochés de manière covalente. Tous les implants avaient une section carrée avec un diamètre oblique de 4.6 mm et étaient insérés dans des trous percés à l'aide de trépans de 4.6 mm dans la mandibule de dix chiens beagle. Les implants de cinq animaux ont étéévalués après une période de guérison d'un mois et de trois mois durant laquelle un marquage fluochrome séquentiel de la néoformation osseuse a été effectué. La formation osseuse a étéévaluée par mesure morphométrique de l'os néoformé autour de l'implant et par pourcentage de contact os/implant. Après un mois, il n'y avait que peu de contact os/implant, variant entre 2.6 et 6.7% dans l'os cortical et 4.4 et 5.7% dans l'os spongieux, sans aucune différence significative entre les trois types d'implants. Après trois mois, les implants avec les surfaces polies montraient respectivement 26.5 et 31.2% d'os cortical et spongieux, tandis que les implants recouverts de collagène avaient 19.5 et 28.4% de contact osseux dans ces zones. Les implants avec le recouvrement RGD avaient les valeurs les plus importantes avec respectivement 42.1% et 49.7%. Les différences entre les types de surface n'étaient pas significatives mais l'augmentation du contact os/implant de 1 à 3 mois après l'opération n'était significative que dans le groupe RGD (P=0.008 et P=0.0000). Les résultats de cette ewtude pilote n'ont donc mis en évidence qu'une maigre preuve que les recouvrements des implants en titane par les petpides RGD sous la forme présente et le dosage présent, pouvaient augmenter la formation osseuse paro?mplantaire dans le processus alvéolaire. Ces résultats requièrent donc davantage de vérifications dans un système expérimental modifié. Zusammenfassung Es war das Ziel dieser Untersuchung, den Einfluss einer organischen Beschichtung von Titanimplantaten auf die periimplantäre Knochenformation und auf den KnochenImplantatkontakt zu analysieren. Drei Typen von Implantaten wurden verwendet: i) Ti6AI4V Implantate mit polierter Oberfläche (Kontrolle 1), ii) Ti6AI4V Implantate mit Kollagenbeschichtung (Kontrolle 2), iii) Ti6AI4V Implantate mit Kollagenbeschichtung und kovalent gebundenen RGD-Peptiden. Alle Implantate hatten einen quadratischen Querschnitt mit einem Querdurchmesser von 4.6 mm. Sie wurden in die Unterkiefer von zehn Beaglehunden in zylindrische Bohrungen mit einem Durchmesser von 4.6 mm mit Pressitz eingesetzt. Die Implantate von je funf Tieren wurden nach einer Helungszeit von einem bzw. drei Monaten ausgewertet. Während der gesamten Zeit wurden sequentielle Fluorochrommarkierungen der Knochenbildung durchgeführt. Die Knochenbildung wurde durch morphometrische Messungen des neugebildeten Knochens um die Implantate und durch Messungen der prozentualen Anteile des Knochen-/Implantatkontakts ausgewertet. Nach 1 Monat war nur wenig Knochen-/Implantatkontakt vorhanden. Er variierte zwischen 2.6 und 6.7% im kortikalen Knochen und zwischen 4.4 und 5.7% im spongiösen Knochen. Zwischen den drei Implantattypen bestanden keine signifikanten Unterschiede. Nach drei Monaten zeigten die Implantate mit polierten Oberflächen 26.5% Knochenkontakt im kortikalen bzw. 31.2% im spongiösen Knochen, während die kollagenbeschichteten Implantate 19.5% und 28.4% Knochenkontakt in diesen Regionen zeigten. Implantate mit RGD-Beschichtung zeigten mit 42.1% bzw. 49.7% die höchsten Werte. Zwischen den Oberflächentypen bestanden keine signifikanten Unterschiede. Nur in der Gruppe mit RGD-beschichteten Implantaten nahm der Knochen-/Implantatkontakt zwischen 1 bis 3 Monaten nach Chirurgie signifikant zu (P=0.008 und P=0.000). Die Resultate dieser zeigen nur mit schwacher Evidenz, dass die Beschichtung von Titanimplantaten mit RGD-Peptiden in der vorliegenden Form und Dosierung die periimplantäre Knochenformation im Alveolarkamm erhöht. Die Resultate müssen daher in einem modifizerten experimentellen Aufbau verifiziert werden. Resumen La intención del presente estudio fue analizar el efecto de la cobertura orgánica de implantes de titanio en la formación de hueso y contacto hueso/implante. Se usaron tres tipos de implantes: i) implantes de Ti6AI4V con superficie pulida (control 1), ii) implantes Ti6AI4V con cubierta de colágeno (control 2), iii) implantes de Ti6AI4V con cubierta de colágeno y péptidos RGD con unión convalente. Todos los implantes tenían secciones cuadradas con un diámetro oblicuo de 4.6 mm y se insertaron a presión en orificios trepanados de 4.6 mm en las mandíbulas de 10 perros beagle. Se evaluaron los implantes de 5 animales tras un periodo de cicatrización de un mes y tres meses los otros cinco, durante este tiempo se llevó a cabo marcado secuencial con fluorocromo de la formación de hueso. La formación de hueso se evaluó mediante mediciones morfométricas del hueso neoformado alrededor del implante y el porcentaje de contacto hueso implante. Tras 1 mes existió muy poco contacto hueso/implante variando entre 2.6 y 6.7% en el hueso cortical y 4.4 y 5.7% en el hueso esponjoso sin diferencias significativas entre los tres tipos de implantes. Tras tres meses, los implantes con superficies pulidas exhibieron un 26.5 y 31.2% en el hueso cortical y esponjoso, respectivamente, mientras que los implantes con cubiertas de colágeno tuvieron un 19.5 y un 28.4% de contacto óseo en estas áreas. Los implantes con cubiertas de RGD mostraron los valores más altos con un 42.1 y un 49.7% respectivamente. Las diferencias ente tipos de superficie como tales no fueron significativas pero el incremento de contacto hueso/implante de 1 a 3 meses tras la operación fue significativo solo en el grupo de implantes con cubierta RGD (P=0.008 y P=0.000). Los resultados de este estudio piloto aunque han mostrado solo una débil evidencia, que la cobertura de implantes de titanio con péptidos RGD en la forma y dosis presente pueden incrementar la formación de hueso periimplantario en el proceso alveolar. Los resultados, por lo tanto, requieren una posterior verificación en una situación experimental modificada. [source] |