A randomized controlled trial comparing patellar retention versus patellar resurfacing in primary total knee arthroplasty: 5-10 year follow-up

ABSTRACT: BACKGROUND: The primary purpose of this randomized controlled trial (RCT) was to compare knee-specific outcomes (stiffness, pain, function) between patellar retention and resurfacing up to 10 years after primary total knee arthroplasty (TKA). Secondarily, we compared re-operation rates. METHODS: 38 subjects with non-inflammatory arthritis were randomized at primary TKA surgery to receive patellar resurfacing (n = 21; Resurfaced group) or to retain their native patella (n = 17; Non-resurfaced group). Evaluations were performed preoperatively, one, five and 10 years postoperatively by an evaluator who was blinded to group allocation. Self-reported kneespecific stiffness, pain and function, the primary outcomes, were measured by the Western Ontario McMaster Osteoarthritis Index (WOMAC). Revision rate was determined at each evaluation and through hospital record review. RESULTS: 30 (88%) and 23 (72%) of available subjects completed the five and 10-year review respectively. Knee-specific scores continued to improve for both groups over the 10-years, despite diminishing overall health with no significant group differences seen. All revisions occurred within five years of surgery (three Non-resurfaced subjects; one Resurfaced subject) (p = 0.31). Two revisions in the Non-resurfaced group were due to persistent anterior knee pain. CONCLUSIONS: We found no differences in knee-specific results between groups at 5-10 years postoperatively. The Non-resurfaced group had two revisions due to anterior knee pain similar to rates reported in other studies. Knee-specific results provide useful postoperative information and should be used in future studies comparing patellar management strategies. ClinicalTrials.gov identifier NCT01500252.     

Genomic characterization of the Taylorella genus

The Taylorella genus comprises two species: Taylorella equigenitalis, which causes contagious equine metritis, and Taylorella asinigenitalis, a closely-related species mainly found in donkeys. We herein report on the first genome sequence of T. asinigenitalis, analyzing and comparing it with the recently-sequenced T. equigenitalis genome. The T. asinigenitalis genome contains a single circular chromosome of 1,638,559 bp with a 38.3% GC content and 1,534 coding sequences (CDS). While 212 CDSs were T. asinigenitalis-specific, 1,322 had orthologs in T. equigenitalis. Two hundred and thirty-four T. equigenitalis CDSs had no orthologs in T. asinigenitalis. Analysis of the basic nutrition metabolism of both Taylorella species showed that malate, glutamate and alpha-ketoglutarate may be their main carbon and energy sources. For both species, we identified four different secretion systems and several proteins potentially involved in binding and colonization of host cells, suggesting a strong potential for interaction with their host. T. equigenitalis seems better-equipped than T. asinigenitalis in terms of virulence since we identified numerous proteins potentially involved in pathogenicity, including hemagluttinin-related proteins, a type IV secretion system, TonB-dependent lactoferrin and transferrin receptors, and YadA and Hep_Hag domains containing proteins. This is the first molecular characterization of Taylorella genus members, and the first molecular identification of factors potentially involved in T. asinigenitalis and T. equigenitalis pathogenicity and host colonization. This study facilitates a genetic understanding of growth phenotypes, animal host preference and pathogenic capacity, paving the way for future functional investigations into this largely unknown genus.     

Naturalization of exotic plant species in north‐eastern North America: trends and detection capacity

Aim To reconstruct historical naturalization trends of exotic vascular plants in Quebec and Massachusetts, two regions that experienced fluctuations in their herbarium specimen collection efforts. We hypothesized that the observed trends are linked to the collection effort and that they differ according to the motive for plant introduction. Methods A checklist of naturalized exotic plant taxa for Quebec, including oldest proof of naturalization and motive for introduction, was built from herbaria, journals, dissertations, theses, bulletins, websites and unpublished records. For Massachusetts, we used the checklist of Sorrie (2005; Rhodora, 107 , 284–329). The collection effort was estimated from a pool of species with specimens from the five largest Quebec herbaria and from the Harvard University Herbarium. Results Naturalization trends of exotic plants in Quebec are similar to those observed in Massachusetts. A large part of the plants naturalized in the 17th, 18th or 19th centuries, with very little naturalization during the last 30–90 years. In general, there is a significant statistical link between herbarium specimen collection effort and the discovery of new naturalized plant taxa. Very few utilitarian plants naturalized in either region during the 20th century. In Quebec, a high number of ornamental plants naturalized during the last 100 years. Main conclusions The link between herbarium specimen collection effort and the discovery of new naturalized plants is real, although not as straightforward as it seems. Our analysis suggests that at least part of the decline in the number of new naturalized exotic plants observed in Quebec and Massachusetts during the last 30–90 years is a direct consequence of the low interest for traditional floristic studies. However, the possibility of a real decline cannot be ruled out. We nevertheless provide here one of the first pieces of evidence of the potential consequences of the decline of local plant collection for environmental management and especially for early detection systems of new invaders.     

Rotor architecture in the yeast and bovine F1-c-ring complexes of F-ATP synthase

The F₁F_O-ATP synthase is a rotary molecular nanomotor. F₁ is a chemical motor driven by ATP hydrolysis while F_O is an electrical motor driven by the proton flow. The two stepping motors are mechanically coupled through a common rotary shaft. Up to now, the three available crystal structures of the F₁c₁₀ sub-complex of the yeast F₁F_O-ATP synthase were isomorphous and then named yF₁c₁₀(I). In this crystal form, significant interactions of the c₁₀-ring with the F₁-head of neighboring molecules affected the overall conformation of the F₁-c-ring complex. The symmetry axis of the F₁-head and the inertia axis of the c-ring were tilted near the interface between the F₁-central stalk and the c-ring rotor, resulting in an unbalanced machine. We have solved a new crystal form of the F₁c₁₀ complex, named yF₁c₁₀(II), inhibited by adenylyl-imidodiphosphate (AMP-PNP) and dicyclohexylcarbodiimide (DCCD), at 6.5 Å resolution in which the crystal packing has a weaker influence over the conformation of the F₁-c-ring complex. yF₁c₁₀(II) provides a model of a more efficient generator. yF₁c₁₀(II) and bovine bF₁c₈ structures share a common rotor architecture with the inertia center of the F₁-stator close to the rotor axis.     

Influence of common non-synonymous Toll-like receptor 4 polymorphisms on bronchopulmonary dysplasia and prematurity in human infants

Bronchopulmonary dysplasia (BPD) is a common chronic lung disease and major risk factor for severe respiratory syncytial virus (RSV) infection among preterm infants. The Toll-like receptor 4 (TLR4) is involved in oxidative injury responses in the lungs. Two non-synonymous single nucleotide polymorphisms in the TLR4 gene have been associated with RSV infection in children. However, it is unclear to what extent this association is confounded by BPD or prematurity. In this study, we analyzed two population-based cohorts of preterm infants at risk for BPD as well as ethnicity-matched infants born at term, to test whether the TLR4 polymorphisms Asp299Gly (rs4986790) and Thr399Ile (rs4986791) are independently associated with BPD or premature birth. In a Canadian cohort (n = 269) composed of a majority of Caucasian preterm infants (BPD incidence of 38%), the TLR4-299 heterozygous genotype was significantly under-represented in infants without BPD (1.6% of infants versus 12% in infants with severe BPD) after adjusting for twins, ethnicity, gestational age, birth weight and gender (p = 0.014). This association was not replicated in a Finnish cohort (n = 434) of premature singletons or first-born siblings of Caucasian descent, although the incidence of BPD was substantially lower in this latter population (15%). We did not detect a significant association (>2-fold) between TLR4 genotypes and prematurity (p>0.05). We conclude that these TLR4 genotypes may have, at best, a modest influence on BPD severity in some populations of high-risk preterm infants. Further studies are warranted to clarify how clinical heterogeneity may impact genetic susceptibility to BPD.     

Novel loci for adiponectin levels and their influence on type 2 diabetes and metabolic traits: a multi-ethnic meta-analysis of 45,891 individuals

Circulating levels of adiponectin, a hormone produced predominantly by adipocytes, are highly heritable and are inversely associated with type 2 diabetes mellitus (T2D) and other metabolic traits. We conducted a meta-analysis of genome-wide association studies in 39,883 individuals of European ancestry to identify genes associated with metabolic disease. We identified 8 novel loci associated with adiponectin levels and confirmed 2 previously reported loci (P = 4.5×10⁻⁸–1.2×10⁻⁴³). Using a novel method to combine data across ethnicities (N = 4,232 African Americans, N = 1,776 Asians, and N = 29,347 Europeans), we identified two additional novel loci. Expression analyses of 436 human adipocyte samples revealed that mRNA levels of 18 genes at candidate regions were associated with adiponectin concentrations after accounting for multiple testing (p<3×10⁻⁴). We next developed a multi-SNP genotypic risk score to test the association of adiponectin decreasing risk alleles on metabolic traits and diseases using consortia-level meta-analytic data. This risk score was associated with increased risk of T2D (p = 4.3×10⁻³, n = 22,044), increased triglycerides (p = 2.6×10⁻¹⁴, n = 93,440), increased waist-to-hip ratio (p = 1.8×10⁻⁵, n = 77,167), increased glucose two hours post oral glucose tolerance testing (p = 4.4×10⁻³, n = 15,234), increased fasting insulin (p = 0.015, n = 48,238), but with lower in HDL-cholesterol concentrations (p = 4.5×10⁻¹³, n = 96,748) and decreased BMI (p = 1.4×10⁻⁴, n = 121,335). These findings identify novel genetic determinants of adiponectin levels, which, taken together, influence risk of T2D and markers of insulin resistance.     

Evidence that the decrease in liver glycogen is associated with the exercise-induced increase in IGFBP-1.

The purpose of the present study was to test the hypothesis that the exercise-induced increase in insulin-like growth factor binding protein (IGFBP)-1 is not always linked to a decrease in blood glucose level and to examine whether the decreasing levels of liver glycogen during exercise may be associated with the increase in IGFBP-1. Three groups of rats were submitted to a 70-min treadmill exercise. One group of rats was fed normally, and the two other groups had their food intake restricted by 50% (50% fast) the night before the experiment. One of these two 50% fasted groups of rats was infused (intravenously) with glucose throughout exercise to maintain euglycemia. Exercise in noninfused 50% fasted rats, compared with the normally fed rats, resulted in significantly lower blood glucose (minute 70) and insulin levels, significantly lower liver glycogen content, no change in IGF-I, and significantly higher increases in free fatty acid, glycerol, beta-hydroxybutyrate, and IGFBP-1. Maintenance of euglycemia during exercise in glucose-infused 50% fasted rats reduced to a large extent the decrease in insulin levels but only slightly attenuated the lipid response and the IGFBP-1 response seen in noninfused 50% fasted rats. Comparisons of all individual liver glycogen and IGFBP-1 values revealed that liver glycogen values were highly (P < 0.001) predictive of the IGFBP-1 response during exercise (R = 0.564). The present results indicate that the IGFBP-1 response during exercise is not always linked to a decrease in plasma glucose and suggest that the increase in IGFBP-1 during exercise may be related to the decrease in liver glycogen content.