Journal articles: 'Sites de fixation des anticorps'

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Deveuve, Quentin, Valérie Gouilleux-Gruart, Gilles Thibault, and Laurie Lajoie. "La région charnière des anticorps thérapeutiques." médecine/sciences 35, no. 12 (December 2019): 1098–105. http://dx.doi.org/10.1051/medsci/2019218.

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La région charnière est une courte séquence des chaînes lourdes (H) d’anticorps liant le Fab (fragment antigen binding) au Fc (fragment crystallisable). Les propriétés fonctionnelles des quatre sous-classes d’immunoglobulines d’isotype G (IgG) résultent en partie des différences de séquence de leurs régions charnières. En effet, certains acides aminés de la partie C-terminale de ces régions charnières (« partie basse ») sont situés au sein ou à proximité des sites de liaison de la molécule C1q de la voie classique du complément et des récepteurs pour la région Fc des IgG (RFcγ) sur les chaînes H d’IgG. Les régions charnières sont également sensibles au clivage protéolytique par de nombreuses protéases du microenvironnement tumoral et/ou inflammatoire pouvant altérer les réponses fonctionnelles. Le format optimal de la charnière reste donc un défi majeur pour le développement de nouveaux anticorps thérapeutiques.

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Ghram, Abdeljelil, A. Chabchoub, M. Boussetta, S. Baazaoui, H. Ibn Amor, and F. Landolsi. "Enquête séroépidémiologique de la rhinopneumonie des équidés en Tunisie." Revue d’élevage et de médecine vétérinaire des pays tropicaux 50, no. 4 (April 1, 1997): 273–76. http://dx.doi.org/10.19182/remvt.9555.

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Une enquête séroépidémiologique, réalisée sur 789 équidés (400 élevés au Nord-Est de la Tunisie, 389 dans la région du Sahel et du Centre), a permis de détecter, par le test de fixation du complément, des anticorps spécifiques contre le virus de la rhinopneumonie équine. Les résultats ont montré que 15 équidés (1,9 %) étaient séropositifs, avec des taux variables d'anticorps fixant le complément. Ces résultats sont discutés en relation avec ceux obtenus par d'autres auteurs en Tunisie et dans les pays voisins.

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Swiontkowski, M. F. "The Care of Pin Sites With External Fixation." Yearbook of Orthopedics 2006 (January 2006): 57–58. http://dx.doi.org/10.1016/s0276-1092(08)70361-4.

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Davies, R., N. Holt, and S. Nayagam. "The care of pin sites with external fixation." Journal of Bone and Joint Surgery. British volume 87-B, no. 5 (May 2005): 716–19. http://dx.doi.org/10.1302/0301-620x.87b5.15623.

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SIAN, P. S., S. BRITTEN, and B. DUFFIELD. "The care of pin sites with external fixation." Journal of Bone and Joint Surgery. British volume 88-B, no. 4 (April 2006): 558. http://dx.doi.org/10.1302/0301-620x.88b4.17636.

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Hao, Ran, Wenming Sun, Qian Liu, Xiaolu Liu, Jialiang Chen, Xianwei Lv, Wei Li, Yu‐ping Liu, and Zhurui Shen. "Efficient Electrochemical Nitrogen Fixation over Isolated Pt Sites." Small 16, no. 22 (April 27, 2020): 2000015. http://dx.doi.org/10.1002/smll.202000015.

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MOUDJOU, M., E. SABUNCU, D. VILETTE, A. LEDUR, and H. LAUDE. "Approche immunochimique de la structure de la protéine cellulaire PrPc ovine. Caractérisation d’anticorps discriminant les glycoformes et les allèles de la protéine Prion chez le mouton." INRAE Productions Animales 17, HS (December 20, 2004): 51–53. http://dx.doi.org/10.20870/productions-animales.2004.17.hs.3627.

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Les Encéphalopathies Spongiformes Transmissibles (EST) sont des maladies neurodégénératives caractérisées par l’accumulation dans le cerveau d’une forme anormale de la protéine prion, la PrP. La PrP cellulaire est une glycoprotéine membranaire qui a deux sites de glycosylation. La susceptibilité des moutons à la tremblante, la plus répandue des EST, est sous le contrôle d’un polymorphisme génétique en position 136, 154 et 171 de la protéine PrP. Différents travaux ont montré que l’efficacité de la conversion de la PrP normale (PrPc) en PrP anormale (PrPsc) pouvait être influencée à la fois par son degré de glycosylation et par sa séquence primaire en acides aminés. Au cours de notre travail de production d’anticorps monoclonaux dirigés contre la PrP ovine, nous avons obtenu de nouveaux anticorps discriminants les différentes formes glycosylées de la PrP. Parmi ces anticorps, nous avons montré que certains présentent une affinité différentielle vis-à-vis des allèles de la PrP, essentiellement en position 171. Cette position est connue pour jouer un rôle majeur dans le contrôle de la résistance (Arginine, R171) et de la sensibilité (Glutamine, Q171) des moutons à la tremblante. Ces anticorps représentent de nouveaux outils pour étudier la relation entre le niveau de glycosylation de la PrPc et sa capacité à être convertie en PrPsc. Ils nous permettront également une analyse plus fine du profil électrophorétique des différentes glycoformes de la PrP anormale dans le cadre du typage de souches de prions. Enfin, ces anticorps peuvent être utilisés pour le génotypage rapide des moutons en vue d’une sélection d’animaux résistants à la tremblante et pour la compréhension des bases moléculaires de la résistance à la tremblante conférée par la présence de l’Arginine en position 171 de la PrP.

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Sigward, Susan M., Keith L. Markolf, Benjamin R. Graves, Jacob M. Chacko, Steven R. Jackson, and David R. McAllister. "Femoral Fixation Sites for Optimum Isometry of Posterolateral Reconstruction*." Journal of Bone and Joint Surgery-American Volume 89, no. 11 (November 2007): 2359–68. http://dx.doi.org/10.2106/00004623-200711000-00005.

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Sigward, Susan M., Keith L. Markolf, Benjamin R. Graves, Jacob M. Chacko, Steven R. Jackson, and David R. McAllister. "Femoral Fixation Sites for Optimum Isometry of Posterolateral Reconstruction*." Journal of Bone & Joint Surgery 89, no. 11 (November 2007): 2359–68. http://dx.doi.org/10.2106/jbjs.f.01132.

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Vitousek, Peter M. "Nutrient Limitation to Nitrogen Fixation in Young Volcanic Sites." Ecosystems 2, no. 6 (October 30, 1999): 505–10. http://dx.doi.org/10.1007/s100219900098.

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Suzuki, Yukihiko, Toshio Tando, Kobu Adachi, Takashi Kudo, and Mitsuru Nakazawa. "Modified Intraocular Lens Intrascleral Fixation Technique Using Two Vitrectomy Ports as Lens Haptic Fixation Sites." Clinical Ophthalmology Volume 14 (May 2020): 1223–28. http://dx.doi.org/10.2147/opth.s247920.

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Newell, Silvia E., Kaitlyn R. Pritchard, Sarah Q. Foster, and Robinson W. Fulweiler. "Molecular evidence for sediment nitrogen fixation in a temperate New England estuary." PeerJ 4 (January 25, 2016): e1615. http://dx.doi.org/10.7717/peerj.1615.

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Primary production in coastal waters is generally nitrogen (N) limited with denitrification outpacing nitrogen fixation (N2-fixation). However, recent work suggests that we have potentially underestimated the importance of heterotrophic sediment N2-fixation in marine ecosystems. We used clone libraries to examine transcript diversity ofnifH(a gene associated with N2-fixation) in sediments at three sites in a temperate New England estuary (Waquoit Bay, Massachusetts, USA) and compared our results to net sediment N2fluxes previously measured at these sites. We observednifHexpression at all sites, including a site heavily impacted by anthropogenic N. At this N impacted site, we also observed mean net sediment N2-fixation, linking the geochemical rate measurement withnifHexpression. This same site also had the lowest diversity (non-parametric Shannon = 2.75). At the two other sites, we also detectednifHtranscripts, however, the mean N2flux indicated net denitrification. These results suggest that N2-fixation and denitrification co-occur in these sediments. Of the unique sequences in this study, 67% were most closely related to uncultured bacteria from various marine environments, 17% to Cluster III, 15% to Cluster I, and only 1% to Cluster II. These data add to the growing body of literature that sediment heterotrophic N2-fixation, even under high inorganic nitrogen concentrations, may be an important yet overlooked source of N in coastal systems.

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Heath, B., P. Sollins, D. A. Perry, and K. Cromack Jr. "Asymbiotic nitrogen fixation in litter from Pacific Northwest forests." Canadian Journal of Forest Research 18, no. 1 (January 1, 1988): 68–74. http://dx.doi.org/10.1139/x88-011.

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Asymbiotic nitrogen fixation in litter was assayed by acetylene reduction across a range of 25 forested sites in the Willamette Valley and Oregon Cascade and Coast ranges and periodically over a year at two Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantations in the Willamette Valley. Laboratory experiments showed that optimal conditions for N fixation by Douglas-fir litter were 200% moisture content and 22 °C. Annual fixation was 1.08 ± 0.13 kg/ha at one Willamette Valley plantation, 0.39 ± 0.06 kg/ha at the other. Fixation rates at the other 23 sites, which were sampled less frequently, ranged from 0 to 5 g N ha−1 day−1 and exceeded trace levels at only six sites, indicating annual totals much less than those at the Willamette Valley plantations. At four coastal and valley sites sampled by litter layer, older L layer Douglas-fir litter fixed the most N per gram dry weight. Percent N, percent C, and the C:N ratio of that litter layer did not differ significantly among sites or correlate with N-fixation rates. Forest-floor litter in most Northwest forests fixes no more than trace amounts of N, at most ~1 kg N ha−1 year−1. These amounts are smaller than N input from precipitation.

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Fonseca-Batista, Debany, Xuefeng Li, Virginie Riou, Valérie Michotey, Florian Deman, François Fripiat, Sophie Guasco, et al. "Evidence of high N<sub>2</sub> fixation rates in the temperate northeast Atlantic." Biogeosciences 16, no. 5 (March 13, 2019): 999–1017. http://dx.doi.org/10.5194/bg-16-999-2019.

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Abstract. Diazotrophic activity and primary production (PP) were investigated along two transects (Belgica BG2014/14 and GEOVIDE cruises) off the western Iberian Margin and the Bay of Biscay in May 2014. Substantial N2 fixation activity was observed at 8 of the 10 stations sampled, ranging overall from 81 to 384 µmol N m−2 d−1 (0.7 to 8.2 nmol N L−1 d−1), with two sites close to the Iberian Margin situated between 38.8 and 40.7∘ N yielding rates reaching up to 1355 and 1533 µmol N m−2 d−1. Primary production was relatively lower along the Iberian Margin, with rates ranging from 33 to 59 mmol C m−2 d−1, while it increased towards the northwest away from the peninsula, reaching as high as 135 mmol C m−2 d−1. In agreement with the area-averaged Chl a satellite data contemporaneous with our study period, our results revealed that post-bloom conditions prevailed at most sites, while at the northwesternmost station the bloom was still ongoing. When converted to carbon uptake using Redfield stoichiometry, N2 fixation could support 1 % to 3 % of daily PP in the euphotic layer at most sites, except at the two most active sites where this contribution to daily PP could reach up to 25 %. At the two sites where N2 fixation activity was the highest, the prymnesiophyte–symbiont Candidatus Atelocyanobacterium thalassa (UCYN-A) dominated the nifH sequence pool, while the remaining recovered sequences belonged to non-cyanobacterial phylotypes. At all the other sites, however, the recovered nifH sequences were exclusively assigned phylogenetically to non-cyanobacterial phylotypes. The intense N2 fixation activities recorded at the time of our study were likely promoted by the availability of phytoplankton-derived organic matter produced during the spring bloom, as evidenced by the significant surface particulate organic carbon concentrations. Also, the presence of excess phosphorus signature in surface waters seemed to contribute to sustaining N2 fixation, particularly at the sites with extreme activities. These results provide a mechanistic understanding of the unexpectedly high N2 fixation in productive waters of the temperate North Atlantic and highlight the importance of N2 fixation for future assessment of the global N inventory.

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Dráberová, Eduarda, Vladimír Viklický, and Pavel Dráber. "Short Communication Exposure of lumenal microtubule sites after mild fixation." European Journal of Cell Biology 79, no. 12 (December 2000): 982–85. http://dx.doi.org/10.1078/0171-9335-00129.

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Huang, Linsong, Xiaoli Gu, and Gengfeng Zheng. "Tuning Active Sites of MXene for Efficient Electrocatalytic N2 Fixation." Chem 5, no. 1 (January 2019): 15–17. http://dx.doi.org/10.1016/j.chempr.2018.12.015.

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Woulds, Clare, James B. Bell, Adrian G. Glover, Steven Bouillon, and Louise S. Brown. "Benthic carbon fixation and cycling in diffuse hydrothermal and background sediments in the Bransfield Strait, Antarctica." Biogeosciences 17, no. 1 (January 2, 2020): 1–12. http://dx.doi.org/10.5194/bg-17-1-2020.

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Abstract. Sedimented hydrothermal vents are likely to be widespread compared to hard substrate hot vents. They host chemosynthetic microbial communities which fix inorganic carbon (C) at the seafloor, as well as a wide range of macroinfauna, including vent-obligate and background non-vent taxa. There are no previous direct observations of carbon cycling at a sedimented hydrothermal vent. We conducted 13C isotope tracing experiments at three sedimented sites in the Bransfield Strait, Antarctica, which showed different degrees of hydrothermalism. Two experimental treatments were applied, with 13C added as either algal detritus (photosynthetic C), or as bicarbonate (substrate for benthic C fixation). Algal 13C was taken up by both bacteria and metazoan macrofaunal, but its dominant fate was respiration, as observed at deeper and more food-limited sites elsewhere. Rates of 13C uptake and respiration suggested that the diffuse hydrothermal site was not the hot spot of benthic C cycling that we hypothesised it would be. Fixation of inorganic C into bacterial biomass was observed at all sites, and was measurable at two out of three sites. At all sites, newly fixed C was transferred to metazoan macrofauna. Fixation rates were relatively low compared with similar experiments elsewhere; thus, C fixed at the seafloor was a minor C source for the benthic ecosystem. However, as the greatest amount of benthic C fixation occurred at the “Off Vent” (non-hydrothermal) site (0.077±0.034 mg C m−2 fixed during 60 h), we suggest that benthic fixation of inorganic C is more widespread than previously thought, and warrants further study.

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Hassan, A. B., and P. R. Cook. "Visualization of replication sites in unfixed human cells." Journal of Cell Science 105, no. 2 (June 1, 1993): 541–50. http://dx.doi.org/10.1242/jcs.105.2.541.

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Sites of DNA replication in nuclei are focally concentrated, suggesting that an underlying structure organizes the activity of many polymerases. As fixation could induce aggregation into foci, we examined the distribution of replication sites in unfixed nuclei. HeLa cells were encapsulated in agarose microbeads, permeabilized in a ‘physiological’ buffer, their DNA polymerizing activity characterized, and replication sites directly labelled by incubation with fluorochrome-dUTP conjugates. Using conventional and digital fluorescence microscopy, 80–250 foci were seen in these unfixed cells. These foci are unlikely to be formed by the aggregation of separate polymerases as most replication activity found in vivo is retained throughout these procedures. Although commonly used fixation methods collapsed or dispersed their periphery, the central core was very stable. Foci remained when approximately 90% chromatin was removed, suggesting they were attached to an underlying structure.

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Beveridge, T. J., and W. S. Fyfe. "Metal fixation by bacterial cell walls." Canadian Journal of Earth Sciences 22, no. 12 (December 1, 1985): 1893–98. http://dx.doi.org/10.1139/e85-204.

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All biomass contains a significant quantity of metallic constituents, and mineralization in living and dead biodebris may contribute to element transport from the hydrosphere into sediments. The anionic cell walls of bacteria are remarkable in their ability to fix metals and provide sites for nucleation and growth of minerals. Results presented show the types of cell wall polymers that are responsible for metal binding in walls of Gram-positive and Gram-negative bacteria.

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Tajima, F. "Relationship between DNA polymorphism and fixation time." Genetics 125, no. 2 (June 1, 1990): 447–54. http://dx.doi.org/10.1093/genetics/125.2.447.

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Abstract When there is no recombination among nucleotide sites in DNA sequences, DNA polymorphism and fixation of mutants at nucleotide sites are mutually related. Using the method of gene genealogy, the relationship between the DNA polymorphism and the fixation of mutant nucleotide was quantitatively investigated under the assumption that mutants are selectively neutral, that there is no recombination among nucleotide sites, and that the population is a random mating population with N diploid individuals. The results obtained indicate that the expected number of nucleotide differences between two DNA sequences randomly sampled from the population is 42% less when a mutant at a particular nucleotide site reaches fixation than at a random time, and that heterozygosity is also expected to be less when fixation takes place than at a random time, but the amount of reduction depends on the value of 4Nv in this case, where v is the mutation rate per DNA sequence per generation. The formula for obtaining the expected number of nucleotide differences between the two DNA sequences for a given fixation time is also derived, and indicates that, even when it takes a large number of generations for a mutant to reach fixation, this number is 33% less than at a random time. The computer simulation conducted suggests that the expected number of nucleotide differences between the two DNA sequences at the time when an advantageous mutant becomes fixed is essentially the same as that of neutral mutant if the fixation time is the same. The effect of recombination on the amount of DNA polymorphism was also investigated by using computer simulation.

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Atul, Parashar, K. Sharma Ramesh, and Makkar Surinder. "Rigid internal fi xation of zygoma fractures: A comparison of two-point and three-point fi xation." Indian Journal of Plastic Surgery 40, no. 01 (January 2007): 18–24. http://dx.doi.org/10.1055/s-0039-1699174.

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ABSTRACT Background:Displaced fractures of the zygomatic bone can result in significant functional and aesthetic sequelae. Therefore the treatment must achieve adequate and stable reduction at fracture sites so as to restore the complex multidimensional relationship of the zygoma to the surrounding craniofacial skeleton. Many experimental biophysical studies have compared stability of zygoma after one, two and three-point fixation with mini plates. We conducted a prospective clinical study comparing functional and aesthetic results of two-point and three-point fixation with mini plates in patients with fractures of zygoma.Materials and Methods:Twenty-two patients with isolated zygomatic fractures over a period of one year were randomly assigned into two-point and three-point fixation groups. Results of fixation were analyzed after completion of three months. This included clinical, radiological and photographic evaluation.Results:The three-point fixation group maintained better stability at fracture sites resulting in decreased incidence of dystopia and enophthalmos. This group also had better malar projection and malar height as measured radiologically, when compared with the two-point fixation group.Conclusion:We recommend three-point rigid fixation of fractured zygoma after accurate reduction so as to maintain adequate stabilization against masticatory forces during fracture healing phase.

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BREMER, E., D. A. RENNIE, and R. J. RENNIE. "DINITROGEN FIXATION OF LENTIL, FIELD PEA AND FABABEAN UNDER DRYLAND CONDITIONS." Canadian Journal of Soil Science 68, no. 3 (August 1, 1988): 553–62. http://dx.doi.org/10.4141/cjss88-053.

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Annual grain legume production has increased substantially in Western Canada over the past 15 yr but more information on the N2-fixing potential of these crops is needed. 15N isotope dilution was used to determine N2 fixation of several grain legumes under dryland field conditions in Saskatchewan. Two cultivars of lentil (Lens culinaris Medik), pea (Pisum sativum L.), and fababean (Vicia faba L.) were grown at five locations in both 1984 and 1985, with all major soil zones represented by at least one location in each year. Drought stress was moderate to severe at all sites in 1984 and at sites in the Brown and Dark Brown soil zones in 1985. Barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) were nearly identical as non-N2-fixing reference crops, but their validity as reference crops for the grain legumes included in this study was not tested. Indigenous rhizobia were incapable of supporting adequate levels of N2 fixation at most sites in this study. Inoculation increased total dry matter, total N and N2 fixation of all grain legume cultivars tested. Proportion of N assimilated from the atmosphere declined with increasing soil nitrate levels and increasing drought stress. Annual rates of N2 fixation were as high as 75, 105 and 160 kg N ha−1 for lentil, pea and fababean, respectively, at sites in the Gray and Gray-Black soil zones in 1985, but declined by an average of 5.3, 7.6 and 10.5 kg N ha−1, respectively, for every cm reduction in moisture use. Maximum rates of N2 fixation in 1984 were about 80 kg ha−1. Fababean fixed the most N2 under wetter conditions, while pea and lentil fixed the most under drought stressed conditions. Key words: 15N isotope dilution, dinitrogen fixation, lentil, pea, fababean, drought stress

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Wendling, Laura A., James B. Harsh, Carl D. Palmer, Melinda A. Hamilton, Heather M. Dion, Jeffrey S. Boyle, and Markus Flury. "Rhizosphere Effects on Cesium Fixation Sites of Soil Containing Micaceous Clays." Soil Science Society of America Journal 69, no. 5 (September 2005): 1652–57. http://dx.doi.org/10.2136/sssaj2004.0286.

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Verettas, D. A. J., C. N. Chatzipapas, G. I. Drosos, K. C. Xarchas, C. Staikos, P. Chloropoulou, K. I. Kazakos, and A. Ververidis. "Maggot infestation (myiasis) of external fixation pin sites in diabetic patients." Transactions of the Royal Society of Tropical Medicine and Hygiene 102, no. 9 (September 2008): 950–52. http://dx.doi.org/10.1016/j.trstmh.2008.05.011.

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Bibbo, Christopher, and Jon Brueggeman. "Prevention and Management of Complications Arising from External Fixation Pin Sites." Journal of Foot and Ankle Surgery 49, no. 1 (January 2010): 87–92. http://dx.doi.org/10.1053/j.jfas.2009.07.026.

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Telling, J., M. Stibal, A. M. Anesio, M. Tranter, I. Nias, J. Cook, G. Lis, et al. "Microbial nitrogen cycling on the Greenland Ice Sheet." Biogeosciences Discussions 8, no. 5 (October 25, 2011): 10423–57. http://dx.doi.org/10.5194/bgd-8-10423-2011.

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Abstract. Microbial nitrogen cycling was investigated along a 79 km transect into the Greenland Ice Sheet (GrIS) in early August 2010. The depletion of dissolved nitrate and production of ammonium (relative to icemelt) in cryoconite holes within 7.5 km of the ice sheet margin suggested microbial uptake and ammonification respectively. Nitrogen fixation (<4.2 μmoles C2H4 m−2 day−1 to 16.3 μmoles C2H4 m−2 day−1) was active in some cryoconite holes at sites up to 5.7 km from the ice sheet margin, with nitrogen fixation inversely correlated to concentrations of inorganic nitrogen. There may be the potential for the zone of nitrogen fixation to progressively extend further into the interior of the GrIS as the melt season progresses as reserves of available nitrogen are depleted. Estimated annual inputs of nitrogen from nitrogen fixation along the transect were at least two orders of magnitude lower than inputs from precipitation, with the exception of a 100 m long marginal debris-rich zone where nitrogen fixation could potentially equal or exceed that of precipitation. The average estimated contribution of nitrogen fixation to the nitrogen demand of net microbial growth at sites along the transect ranged from 0% to 17.5%.

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Smith, Conrad Kay, M. L. Hull, and S. M. Howell. "Lengthening of a Single-Loop Tibialis Tendon Graft Construct After Cyclic Loading: A Study Using Roentgen Stereophotogrammetric Analysis." Journal of Biomechanical Engineering 128, no. 3 (November 16, 2005): 437–42. http://dx.doi.org/10.1115/1.2187038.

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Although single-loop tibialis tendon allografts have increased in popularity owing to their many advantages over patellar tendon and double-loop hamstring tendon autografts, some percentage of the patient population do not have clinically stable knees following anterior cruciate ligament reconstruction with single-loop tibialis tendon allografts. Therefore, it would be advantageous to determine the causes of increased anterior laxity which ultimately must be traced to lengthening of the graft construct. One objective of this study was to demonstrate the feasibility of using Roentgen stereophotogrammetric analysis (RSA) to determine the causes of lengthening of a single-loop graft construct subjected to cyclic loading. A second objective was to determine which cause(s) contributes most to an increase in length of this graft construct. Radio-opaque markers were inserted into ten grafts to measure the lengthening at the sites of the tibial and femoral fixations and between the sites of fixation. Each graft was passed through a tibial tunnel in a calf tibia, looped around a rigid cross-pin, and fixed to the tibia with a Washerloc fixation device. The grafts were cyclically loaded for 225,000 cycles from 20to170N. Prior to and at intervals during the cyclic loading, simultaneous radiographs were taken. RSA was used to determine the three-dimensional coordinates of the markers from which the lengthening at the sites of fixation and between the sites of fixation was computed at each interval. The sites of the femoral and tibial fixations were the largest contributors to the increase in length of the graft construct, with maximum average values of 0.68 and 0.55 mm, respectively, after 225,000 cycles. The graft substance between the sites of fixation contributed least to lengthening of the graft, with a maximum average value of 0.31 mm. Ninety percent of the maximum average values occurred before 100,000 cycles of loading for the largest contributors. RSA proved to be a useful method for measuring lengthening due to all three causes. Lengthening of the graft construct at the sites of both fixations is sufficiently large that the combined contributions may manifest as a clinically important increase in anterior laxity.

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Augusto, L., N. Crampon, E. Saur, M. R. Bakker, S. Pellerin, C. de Lavaissière, and P. Trichet. "High rates of nitrogen fixation of Ulex species in the understory of maritime pine stands and the potential effect of phosphorus fertilization." Canadian Journal of Forest Research 35, no. 5 (May 1, 2005): 1183–92. http://dx.doi.org/10.1139/x05-054.

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Nitrogen (N2) fixation by Ulex species was studied in a range of mature maritime pine (Pinus pinaster Ait.) stands as well as in a phosphorus (P) fertilization trial in a young (6-year-old) open pine stand. The biomass was estimated by allometric relationships, and the percentage of N derived from atmosphere was calculated according to the natural 15N abundance method. Ulex stand biomass was lower in the mature pine stand than in the young open pine stand. In the latter pine stand, Ulex mean annual biomass increment ranged from 1 to 5 Mg·ha1·year1, increasing with P fertilization dose, as did the Ulex stand biomass, ranging from 5.4 to 31.1 Mg·ha1 after six growing seasons in the most highly fertilized treatment. For the sites where the natural 15N abundance method was applicable, the calculated percentage of N in the Ulex europaeus L. tissues derived from atmosphere was very high (mean = 82%; range = 59%100%). At the other sites, the N2 fixation was probably also very important but could not be calculated with confidence. Here, the mean fixation rate of the former sites was used to calculate the N2 fixation flux. The estimated annual N2 fixation flux ranged from 0.5 to 5.1 kg N·ha1·year1 in the mature pine stands. In the young open pine stand, the Ulex understory fixation ranged from 8.1 to 57.4 kg N·ha1·year1, increasing with P fertilization dose. Considering the low levels of N fluxes in theses ecosystems, these figures are very high.

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Desclos-Theveniau, Marie, Martine Bonnaure-Mallet, and Vincent Meuric. "Peptidylarginine désiminases du microbiote buccal et polyarthrite rhumatoïde." médecine/sciences 36, no. 5 (May 2020): 465–71. http://dx.doi.org/10.1051/medsci/2020078.

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Ces dernières années, des études se sont focalisées sur l’existence d’une association entre la parodontite et la polyarthrite rhumatoïde (PR), suggérant l’implication du microbiote buccal dans le déclenchement de cette maladie auto-immune des articulations. D’un point de vue clinique, les deux pathologies reposent sur un processus inflammatoire qui conduit à une érosion osseuse. Elles font également intervenir une modification post-traductionnelle appelée citrullination. Dans le cas de la PR, la citrullination de certains sites protéiques par les peptidylarginine désiminases (PAD) aboutit à la production d’auto-anticorps. C’est la découverte d’une PAD exprimée par la bactérie Porphyromonas gingivalis qui a orienté de nombreuses études vers l’analyse d’une association entre ces deux pathologies.

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Jurgensen, M. F., R. T. Graham, M. J. Larsen, and A. E. Harvey. "Clear-cutting, woody residue removal, and nonsymbiotic nitrogen fixation in forest soils of the Inland Pacific Northwest." Canadian Journal of Forest Research 22, no. 8 (August 1, 1992): 1172–78. http://dx.doi.org/10.1139/x92-155.

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The effect of clear-cutting and woody residue removal on soil nonsymbiotic nitrogen fixation, as estimated by the acetylene reduction technique, was investigated on a subalpine fir (Abieslasiocarpa (Hook.) Nutt.) site in western Montana and on a cedar (Thujaplicata (Donn ex D. Don) Lindl.)–hemlock (Tsugaheterophylla (Raf) Sarg.) site in northern Idaho. Nitrogen fixation in the forest floor, soil wood, and mineral soil on the subalpine fir site averaged 0.9 kg N•ha−1•year−1 in the uncut stand. This nitrogen input was reduced by 10% after clear-cutting followed by prescribed burning, and by 22% after clear-cutting followed by intensive residue removal. Nitrogen fixation in the uncut cedar–hemlock stand averaged 1.1 kg N•ha−1•year−1 and was reduced by 26% after prescribed burning. Clear-cutting only and clear-cutting followed by intensive woody residue removal had little effect on nitrogen fixation. However, large amounts of woody residue left on the cut site nearly doubled the amounts of nitrogen fixation compared with the uncut stand. Lower nitrogen fixation after harvesting on both the Idaho and Montana sites was due mostly to reductions in forest floor and large woody residue. Replacement of nitrogen losses from prescribed burning on these sites by nonsymbiotic nitrogen fixation and precipitation would take from 150 to 400 years, depending on the severity of the bum treatments.

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Jurgensen, M. F., M. J. Larsen, R. T. Graham, and A. E. Harvey. "Nitrogen fixation in woody residue of northern Rocky Mountain conifer forests." Canadian Journal of Forest Research 17, no. 10 (October 1, 1987): 1283–88. http://dx.doi.org/10.1139/x87-198.

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N fixation rates, as estimated by the acetylene reduction technique, were determined for large woody residues on four old growth conifer sites in western Montana and northern Idaho. Residue loadings ranged from <50 Mg ha−1 on a warm, dry Douglas-fir site in Montana to >150 Mg ha−1 on a highly productive, wet, cedar–hemlock site in northern Idaho. Lignin and carbohydrate analyses indicated that wood on these sites was being decayed primarily by brown rot fungi. Ethylene production rates increased on all sites as wood decay progressed. Assuming that N-fixing bacteria were active for 180 days year−1, N fixed in woody residues ranged from a high of nearly 1.5 kg ha−1 year−1 on a cedar–hemlock site to a low of 0.16 kg ha−1 year−1 on a Douglas-fir site. The application of the N fixation results from this study to the northern Rocky Mountain region indicated that the majority of stands in the Douglas-fir, subalpine fir, and cedar–hemlock cover types would have N gains <0.5 kg ha−1 year−1. However, in some areas where residue loadings are heavy, such as overmature stands on cool, moist sites, or following harvesting, N gains could be much greater.

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Schlechter, John A., Shawn V. Nguyen, and Katie L. Fletcher. "Meniscal Repairs in the Adolescent Knee: Can the Number of Fixation Sites Improve Outcomes?" Orthopaedic Journal of Sports Medicine 7, no. 11 (November 1, 2019): 232596711988196. http://dx.doi.org/10.1177/2325967119881963.

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Background: Meniscal pathology in children and adolescents is now a common occurrence because of their ever-increasing participation in youth sports. Purpose: To investigate the outcomes of arthroscopic meniscal repair in an adolescent cohort and analyze the variables that may affect outcomes, specifically the number of fixation sites utilized during repair. Study Design: Case series; Level of evidence, 4. Methods: A retrospective review of all children and adolescents younger than 18 years who underwent arthroscopic meniscal repair at a single institution was performed. Patient characteristics, operative details (eg, tear pattern, tear location, method of repair, and number of fixation sites [determined based on the number of sutures used for repair]), and concomitant procedures were recorded. Results: A total of 175 primary meniscal repairs met inclusion criteria and were analyzed. Of this cohort, 115 were able to be contacted and were included in the final study cohort. The mean follow-up was 41 months. The mean age of the children was 14.9 years, and 91 (79%) had concomitant anterior cruciate ligament reconstructions with their meniscal repair. The mean Pediatric International Knee Documentation Committee functional outcome score was 91 (range, 43-100), and the mean Lysholm functional outcome score was 91 (range, 47-100). Of the 115 meniscal repairs, there were a total of 19 reoperations (17%); 15 (13%) were because of meniscal repair failures. The only variable that statistically increased the risk of meniscal repair failure was low number of fixation sites, with the failure group having a mean of 1.79 sutures and the nonfailure group having a mean of 2.97 sutures ( P = .03). Conclusion: Successful meniscal repairs and a lower failure rate may be achieved with a greater number of fixation sites with promising results at a minimum 2-year follow-up. Validated functional outcome scores were good, with a 13% failure rate. Larger cohort, longer term, multicenter multisurgeon data are still needed to further elucidate the number of fixation sites needed when performing a meniscal repair in the pediatric and adolescent knee.

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Huang, Rong, Xiaoman Li, Wanguo Gao, Xu Zhang, Sen Liang, and Min Luo. "Recent advances in photocatalytic nitrogen fixation: from active sites to ammonia quantification methods." RSC Advances 11, no. 24 (2021): 14844–61. http://dx.doi.org/10.1039/d0ra10439f.

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34

Gandhi, Neeraj J., and Edward L. Keller. "Comparison of Saccades Perturbed by Stimulation of the Rostral Superior Colliculus, the Caudal Superior Colliculus, and the Omnipause Neuron Region." Journal of Neurophysiology 82, no. 6 (December 1, 1999): 3236–53. http://dx.doi.org/10.1152/jn.1999.82.6.3236.

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Over the past decade, considerable research efforts have been focused on the role of the rostral superior colliculus (SC) in control of saccades. The most recent theory separates the deeper intermediate layers of the SC into two functional regions: the rostral pole of these layers constitutes a fixation zone and the caudal region comprises the saccade zone. Sustained activity of fixation neurons in the fixation zone is argued to maintain fixation and help prevent saccade generation by exciting the omnipause neurons (OPNs) in the brain stem. This hypothesis is in contrast to the traditional view that the SC contains a topographic representation of the saccade motor map on which the rostral pole of the SC encodes signals for generating small saccades (<2°) instead of preventing them. There is therefore an unresolved controversy about the specific role on the most rostral region of the SC, and we reexamined its functional contribution by quantifying and comparing spatial and temporal trajectories of 30° saccades perturbed by electrical stimulation of the rostral pole and more caudal regions in the SC and of the OPN region. If the rostral pole serves to preserve fixation, then saccades perturbed by stimulation should closely resemble interrupted saccades produced by stimulation of the OPN region. If it also contributes to saccade generation, then the disrupted movements would better compare with redirected saccades observed after stimulation of the caudal SC. Our experiments revealed two significant findings: 1) the locus of stimulation was the primary factor determining the perturbation effect. If the directions of the target-directed saccade and stimulation-evoked saccade were aligned and if the stimulation was delivered within approximately the rostral 2 mm (<10° amplitude) of SC, the ongoing saccade stopped in midflight but then resumed after stimulation end to reach the original visually specified goal with close to normal accuracy. When stimulation was applied at more caudal sites, the ongoing saccade directly reached the target location without stopping at an intermediate position. If the directions differed considerably, both initial and resumed components were typically observed for all stimulation sites. 2) A quantitative analysis of the saccades perturbed from the fixation zone showed significant deviations from their control spatial trajectories. Thus they resembled redirected saccades induced by caudal SC stimulation and differed significantly from interrupted saccades produced by OPN stimulation. The amplitude of the initial saccade, latency of perturbation, and spatial redirection were greatest for the most caudal sites and decreased gradually for rostral sites. For stimulation sites within the rostral pole of SC, the measures formed a smooth continuation of the trends observed in the saccade zone. As these results argue for the saccade zone concept, we offer reinterpretations of the data used to support the fixation zone model. However, we also discuss scenarios that do not allow an outright rejection of the fixation zone hypothesis.

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Wang, Zheng, Qianjie Xie, Yajun Wang, Yu Shu, Cong Li, and Yehua Shen. "The fixation of CO2 by epoxides over nickel-pyrazolate-based metal–organic frameworks." New Journal of Chemistry 44, no. 42 (2020): 18319–25. http://dx.doi.org/10.1039/d0nj03692g.

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Ni-based MOFs with Lewis acid sites was developed for CO₂ fixation with epoxides into cyclic carbonates, and a comparative study shows that the density and accessibility of the Lewis acid sites in the MOFs greatly influence the catalytic performance.

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Yang, Lianghao, Changhyeok Choi, Song Hong, Zhiming Liu, Zhenqing Zhao, Mengmeng Yang, Huidong Shen, et al. "Single yttrium sites on carbon-coated TiO2 for efficient electrocatalytic N2 reduction." Chemical Communications 56, no. 74 (2020): 10910–13. http://dx.doi.org/10.1039/d0cc01136c.

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37

Yoneyama, Terakado-Tonooka, Bao, and Minamisawa. "Molecular Analyses of the Distribution and Function of Diazotrophic Rhizobia and Methanotrophs in the Tissues and Rhizosphere of Non-Leguminous Plants." Plants 8, no. 10 (October 11, 2019): 408. http://dx.doi.org/10.3390/plants8100408.

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Biological nitrogen fixation (BNF) by plants and its bacterial associations represent an important natural system for capturing atmospheric dinitrogen (N2) and processing it into a reactive form of nitrogen through enzymatic reduction. The study of BNF in non-leguminous plants has been difficult compared to nodule-localized BNF in leguminous plants because of the diverse sites of N2 fixation in non-leguminous plants. Identification of the involved N2-fixing bacteria has also been difficult because the major nitrogen fixers were often lost during isolation attempts. The past 20 years of molecular analyses has led to the identification of N2 fixation sites and active nitrogen fixers in tissues and the rhizosphere of non-leguminous plants. Here, we examined BNF hotspots in six reported non-leguminous plants. Novel rhizobia and methanotrophs were found to be abundantly present in the free-living state at sites where carbon and energy sources were predominantly available. In the carbon-rich apoplasts of plant tissues, rhizobia such as Bradyrhizobium spp. microaerobically fix N2. In paddy rice fields, methane molecules generated under anoxia are oxidized by xylem aerenchyma-transported oxygen with the simultaneous fixation of N2 by methane-oxidizing methanotrophs. We discuss the effective functions of the rhizobia and methanotrophs in non-legumes for the acquisition of fixed nitrogen in addition to research perspectives.

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Wagner, Scott C., Benjamin B. Chi, Wade T. Gordon, and Benjamin K. Potter. "Retrograde Intramedullary Fixation of Long Bone Fractures Through Ipsilateral Traumatic Amputation Sites." Journal of Orthopaedic Trauma 29, no. 6 (June 2015): e203-e207. http://dx.doi.org/10.1097/bot.0000000000000248.

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Brasell, H. M., S. K. Daviesandj, and P. Mattay. "Nitrogen fixation associated with bryophytes colonizing burnt sites in Southern Tasmania, Australia." Journal of Bryology 14, no. 1 (January 1986): 139–49. http://dx.doi.org/10.1179/jbr.1986.14.1.139.

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40

Pirjamalineisiani, Adel, Mohsen Sarafbidabad, Nima Jamshidi, and Fatemeh Abedi Esfahani. "Finite element analysis of post dental implant fixation in drilled mandible sites." Computers in Biology and Medicine 81 (February 2017): 159–66. http://dx.doi.org/10.1016/j.compbiomed.2016.11.012.

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Casciato, Dominick J., Ryan Stone, John Thompson, Marissa Venero, Michael Chiu, Jonathan Blum, Ian Barron, and Christopher Hyer. "Radiodensity analysis of medial column superconstruct fixation sites in midfoot Charcot neuroarthropathy." Foot & Ankle Surgery: Techniques, Reports & Cases 1, no. 3 (2021): 100044. http://dx.doi.org/10.1016/j.fastrc.2021.100044.

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Karpati, Eva, Peter Kiss, Tamas Ponyi, Istvan Fendrik, Miklos de Zamaroczy, and Laszlo Orosz. "Interaction of Azospirillum lipoferumwith Wheat Germ Agglutinin Stimulates Nitrogen Fixation." Journal of Bacteriology 181, no. 13 (July 1, 1999): 3949–55. http://dx.doi.org/10.1128/jb.181.13.3949-3955.1999.

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ABSTRACT In vitro, the nitrogen fixation capability of A. lipoferum is efficiently increased in the presence of wheat germ agglutinin (WGA). A putative WGA-binding receptor, a 32-kDa protein, was detected in the cell capsule. The stimulatory effect requiredN-acetyl-d-glucosamine dimer (GlcNAcdi) terminated sugar side chains of the receptor and was dependent on the number of GlcNAcdi links involved in receptor-WGA interface. Binding to the primary sugar binding sites on WGA had a larger stimulatory effect than binding to the secondary sites. The WGA-receptor complex generated stimulus led to elevated transcription of the nifH and nifA genes and of the glnBA gene cluster but not of the glnA gene from its own promoter. There may well be a signalling cascade contributing to the regulation of nitrogen fixation.

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De Santis, Enzo, Erick Ricardo Silva, Evandro Neto Carneiro Martins, Riccardo Favero, Daniele Botticelli, and Samuel Porfirio Xavier. "Healing at the Interface Between Autologous Block Bone Grafts and Recipient Sites Using n-Butyl-2-Cyanoacrylate Adhesive as Fixation: Histomorphometric Study in Rabbits." Journal of Oral Implantology 43, no. 6 (December 1, 2017): 447–55. http://dx.doi.org/10.1563/aaid-joi-d-17-00108.

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The aim of the present split-mouth (split-plot) study was to describe the sequential healing in the interface between autologous bone grafts and recipient parent bone, fixed using an n-butyl-2-cyanoacrylate adhesive with or without an additional titanium fixation screw. Bone grafts were collected from the calvaria and fixed to the lateral aspect of the mandible in 24 rabbits. The cortical layers of the recipient sites were perforated, and the grafts were randomly fixed using an n-butyl-2-cyanocrylate adhesive, either alone or in conjunction with a 1.5 mm × 6.0 mm titanium fixation screw. The animals were sacrificed after 3, 7, 20, and 40 days, and histomorphometric evaluations of the interface between graft and parent bone were performed. Only 2 of 6 grafts in each group were partially incorporated to the parent bone after 40 days of healing. The remaining grafts were separated from the parent bone by adhesive and connective tissue. It was concluded that the use of n-butyl-2-cyanoacrylate as fixation of an autologous bone graft to the lateral aspect of the mandible was able to maintain the fixation over time but did not incorporate the graft to the recipient sites. Use of fixation screws did not improve the healing.

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Thordarson, David B., and Graham Hurvitz. "PLA Screw Fixation of Lisfranc Injuries." Foot & Ankle International 23, no. 11 (November 2002): 1003–7. http://dx.doi.org/10.1177/107110070202301106.

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Fourteen patients with Lisfranc injuries were treated with open reduction and internal fixation with PLA absorbable screw fixation by a single surgeon. From one to four PLA screws were used in each case (average two). In four patients, K-wires were inserted and removed at six weeks following surgery for instability of the fourth and/or fifth tarsometatarsal joints. Average follow-up was 20 months (range, three to 45 months). No patient was noted to have a soft tissue reaction to the screws. No evidence of osteolysis was noted on any of the follow-up X-rays at the screw sites. No loss of reduction was noted in any follow-up X-rays compared to immediate postoperative radiographs. The use of absorbable screws in this small series was found to be safe, without reaction and obviated the need for screw removal at short-term follow-up.

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Izawa, Yoshiko, Hisao Suzuki, and Yoshikazu Shinoda. "Suppression of Visually and Memory-Guided Saccades Induced by Electrical Stimulation of the Monkey Frontal Eye Field. II. Suppression of Bilateral Saccades." Journal of Neurophysiology 92, no. 4 (October 2004): 2261–73. http://dx.doi.org/10.1152/jn.00085.2004.

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To understand the neural mechanism of fixation, we investigated effects of electrical stimulation of the frontal eye field (FEF) and its vicinity on visually guided (Vsacs) and memory-guided saccades (Msacs) in trained monkeys and found that there were two types of suppression induced by the electrical stimulation: suppression of ipsilateral saccades and suppression of bilateral saccades. In this report, we characterized the properties of the suppression of bilateral Vsacs and Msacs. Stimulation of the bilateral suppression sites suppressed the initiation of both Vsacs and Msacs in all directions during and ∼50 ms after stimulation but did not affect the vector of these saccades. The suppression was stronger for ipsiversive larger saccades and contraversive smaller saccades, and saccades with initial eye positions shifted more in the saccadic direction. The most effective stimulation timing for the suppression of ipsilateral and contralateral Vsacs was ∼40–50 ms before saccade onset, indicating that the suppression occurred most likely in the superior colliculus and/or the paramedian pontine reticular formation. Suppression sites of bilateral saccades were located in the prearcuate gyrus facing the inferior arcuate sulcus where stimulation induced suppression at ≤40 μA but usually did not evoke any saccades at 80 μA and were different from those of ipsilateral saccades where stimulation evoked saccades at ≤50 μA. The bilateral suppression sites contained fixation neurons. The results suggest that fixation neurons in the bilateral suppression area of the FEF may play roles in maintaining fixation by suppressing saccades in all directions.

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Crosby, Lynn A., and Gordon R. Bozarth. "Fixation Comparison for Chevron Osteotomies." Foot & Ankle International 19, no. 1 (January 1998): 41–43. http://dx.doi.org/10.1177/107110079801900108.

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A comparison study of temporary K-wire fixation, permanent Herbert Whipple screw fixation, versus no osteotomy fixation was performed on distal chevron osteotomies for hallux valgus deformities. Nineteen chevron osteotomies were performed on 17 patients. Six patients received a Herbert Whipple screw for fixation, seven patients received temporary K-wire fixation, and six patients received no fixation for the chevron osteotomy. The average postoperative hallux valgus (HV) angle improved by 7.1° with no fixation, 6.3° with temporary K-wire fixation, and 9.5° with Herbert Whipple screw fixation. Comparison of the three groups using the Student's t-test revealed no statistical difference between the three groups ( P = 0.6). The increased anesthesia time and operative costs for Herbert Whipple screw fixation was found to be statistically significant in comparison with the use of no fixation ( P = <0.001). Time and cost studies were not significantly different for the K-wire and no fixation groups. Follow-up averaged 3.3 years. All patients reported satisfaction with the procedure and an improvement of their preoperative complaints. No significant difference in patient satisfaction was found to exist between the groups receiving fixation and those who did not have fixation. The results of this study can find no long-term benefit when comparing costs and patient satisfaction with the use of any temporary or permanent fixation of osteotomy sites when performing chevron osteotomies.

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47

Vasseur, P. B., J. J. Rodrigo, W. Johnson, P. H. Kass, and B. J. Van Vechten. "A Comparison of Four Different Methods of Fixation of Osteochondral Fragments." Veterinary and Comparative Orthopaedics and Traumatology 06, no. 02 (1993): 80–84. http://dx.doi.org/10.1055/s-0038-1633024.

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SummaryFixation methods for osteochondral shell grafts were studied using replace-ment of a femoral trochlear autograft in rabbits as the model. Twenty skeletally mature rabbits were divided into four groups with five rabbits in each. The articular cartilage of the femoral trochlea, including 2.0 mm of subchondral bone, was removed using a sagittal bone saw. The grafts were immediately reattached using either small Kirschner pins (K-pins), polydioxanone pins (PDP), polydioxanone suture (PDS), or polymethylmethacrylate (PMMA) cement. Six months postoperatively the rabbits were killed and the graft sites compared to the contralateral control using radiography, gross examination, Safranin-O and H & E staining, and sulphate-35 radioactive uptake. Mild degenerative joint changes were evident radio-graphically in all of the operated joints. Articular surface defects at the graft sites were common and included small craters and erosions; a few had larger areas devoid of cartilage. Defects associated with the pin entrance sites were common in the K-pin and PD P groups. The PDS group had the least number of animals with articular surface defects. Safranin-O staining was complete in the PDS group, partial or complete in the K-pin and PD P groups, and partial in all of the joints in the PMM A group. H & E preparations of the cartilage sections were graded from 1 (normal cartilage) to 5 (multiple fissures, severe degradation). The PDS group had a mean (SD) score of 1.8 (0.8), the PD P group 2.4 (1.1), the K-pin group 2.5 (1.3), and the PMM A group 4.6 (0.6). The scores for the PMM A group were significantly greater then the scores for the other groups (p <0.05). The mean (SD) for radioactive counts per minute/mg tissue in treated graft sites as a percent of control was PDS: 130 (83); PDP : 115 (14); K-pins: 92 (42); PMMA : 91 (29). The relative percentages for radioactive uptake were not significantly different (P >0.05). Graft fixation using PDS, PDP, or K-pins was technically easy to perform and the results were generally satisfactory. Fixation using PMM A was technically demanding and histological evidence of moderate to severe cartilage degradation was present in all treated joints.Femoral trochlear autografts in rabbits were used to study fixation methods for osteochondral graft fragments. Six months after the operations the graft sites were evaluated using radiographs, gross examination, Safranin-O and H & E staining, and sulphate-35 radioactive uptake. Grafts stabilized using polydioxanone suture had the least number of articular surface defects and the most complete Safranin-O staining.

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Rochat, M. C., T. A. Snider, M. E. Payton, and J. T. Walker. "The relevance of threaded external skeletal fixation pin insertion speed in canine bone with and without predrilling." Veterinary and Comparative Orthopaedics and Traumatology 27, no. 04 (2014): 249–56. http://dx.doi.org/10.3415/vcot-14-01-0009.

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SummaryObjectives: The effects of insertion speed in revolutions per minute (RPM) and pilot hole predrilling for placement of threaded external skeletal fixation pins on temperature and morphological damage in cortical bone were evaluated. The null hypothesis states that insertion speed and predrilling will have no significant effect on temperature and morphological damage.Methods: Fixation pins were inserted into cadaveric canine femurs at speeds of 700 RPM and 150 RPM, with and without predrilling. Temperature was measured at each cortex 0.5 mm and 3.0 mm from each insertion site. Samples were examined grossly and by scanning electron microscopy for evidence of morphological damage. Data were analysed for maximum temperature, temperature increase, sites above thermal necrosis thresholds, microcracks, thread quality and gross damage.Results: Predrilling had a significant effect on maximum temperature, temperature increase, sites exceeding necrosis thresholds, microcracks, thread quality and gross damage. Speed of insertion had no significant effect on any of the measured parameters following predrilling, but had a significant effect on thread quality without predrilling.Clinical significance: Our results fail to reject the null hypothesis concerning insertion speed, which had no significant effect on thermal damage, and minimal effect on morphological damage, which was negated by predrilling. Our results reject the null hypothesis concerning predrilling and support the practice of predrilling fixation pin insertion sites.

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Malisius, Rainer, Hartmut Merz, Boris Heinz, Evariste Gafumbegete, Britta U. Koch, and Alfred C. Feller. "Constant Detection of CD2, CD3, CD4, and CD5 in Fixed and Paraffin-embedded Tissue Using the Peroxidase-mediated Deposition of Biotin-Tyramide." Journal of Histochemistry & Cytochemistry 45, no. 12 (December 1997): 1665–72. http://dx.doi.org/10.1177/002215549704501210.

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Immunohistochemical methods are widely used for diagnostic purposes in histopathology. However, the use of most monoclonal anti-leukocyte antibodies is limited to frozen tissues. Initially, it was believed that formalin fixation in particular, which is the gold standard for morphological tissue preservation, destroys most of the antigen binding sites. In recent years, protease digestion and the introduction of microwave techniques have significantly enhanced the sensitivity of immunohistochemical techniques, and a variety of hidden antigen sites in formalin-fixed tissue have been retrieved for initially unreactive antibodies. It therefore became clear that many of the leukocyte antigens are not irreversibly destroyed but are most probably masked during the fixation process. We developed a technique combining optimized pretreatment of formalin-fixed tissue with a dramatic enhancement of the immunohistochemical sensitivity and named it the ImmunoMax method. The ImmunoMax method proves that by optimizing the technique at the following three levels it is possible to detect formalin-sensitive leukocyte antigens: (a) standard fixation of the tissue; (b) sufficient antigen unmasking; and (c) increasing the substrate turnover by multiplication of binding sites with subsequent enhancement of the immunohistochemical reaction. Using this optimized ImmunoMax method, we were able to detect CD2, CD3, CD4, and CD5 with conventional monoclonal antibodies in formalin-fixed, paraffin-embedded tissue specimens of various lymphoid tissues.

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Grover, Dustin, Dustin Thompson, M. L. Hull, and S. M. Howell. "Empirical Relationship Between Lengthening an Anterior Cruciate Ligament Graft and Increases in Knee Anterior Laxity: A Human Cadaveric Study." Journal of Biomechanical Engineering 128, no. 6 (April 20, 2006): 969–72. http://dx.doi.org/10.1115/1.2378931.

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Lengthening of an anterior cruciate ligament (ACL) graft construct can occur as a result of lengthening at the sites of tibial and/or femoral fixation and manifests as an increase in anterior laxity. Although lengthening at the site of fixation has been measured for a variety of fixation devices, it is difficult to place these results in a clinical context because the mathematical relationship between lengthening of an ACL graft construct and anterior laxity is unknown. The purpose of our study was to determine empirically this relationship. Ten cadaveric knees were reconstructed with a double-looped tendon graft. With the knee in 25° of flexion, the position of the proximal end of the graft inside the femoral tunnel was adjusted by moving the femoral fixation device until the anterior laxity at an applied anterior force of 134N matched that of the intact knee. In random order, the graft construct was lengthened 1, 2, 3, 4, and 5mm by moving the femoral fixation device distally along the femoral tunnel and anterior laxity was measured. The increase in the length of the graft construct was related to the increase in anterior laxity by a simple linear regression model. Lengthening the graft construct from 1 to 5mm caused an equal increase in anterior laxity (slope=1.0mm∕mm, r2=0.800, p<0.0001). Because an anterior laxity increase of 3mm or greater in a reconstructed knee is considered unstable clinically and because many fixation devices in widespread use clinically allow 3mm or greater of lengthening in in vitro tests, our empirical relationship indicates that lengthening at the site of fixation probably is an important cause of knee instability following ACL reconstructive surgery. Our empirical relation also indicates that an important criterion in the design of future fixation devices is that lengthening at the sites of fixation in in vitro tests should be limited to less than 3mm.

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Journal articles on the topic 'Sites de fixation des anticorps'

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