Rats genetically selected for low and high aerobic capacity exhibit altered soleus muscle myofilament functions.

Aerobic exercise capacity is critical to bodily health. As a model to investigate the mechanisms that determine health and disease, we employed low (LCR) and high (HCR) capacity running rat models selectively bred to concentrate the genes responsible for divergent aerobic running capacity. To investigate the skeletal muscle contribution to this innate difference in running capacity we employed an approach combining examination of the myofilament protein composition and contractile properties of the fast fiber extensor digitorum longus (EDL) and slow fiber soleus (SOL) muscles from LCR and HCR rats. Intact muscle force experiments demonstrate that SOL, but not EDL, muscles from LCR rats exhibit a three times greater decrease in fatigued force. To investigate the mechanism of this increased fatigability in the LCR SOL muscle, we determined the myofilament protein composition and functional properties. Force-Ca2+ measurements demonstrate decreased Ca2+ sensitivity of single skinned SOL muscle fibers from LCR compared with that of HCR rats. Segregating SOL fibers into fast and slow types demonstrates that the decreased Ca2+ sensitivity in LCR SOL results from a specific decrease in slow-type SOL fiber Ca2+ sensitivity such that it was similar to that of fast-type fibers. These results identify that the altered myofilament contractile properties of LCR SOL slow-type fibers result in a fast muscle type Ca2+ sensitivity and the LCR muscle phenotype. Overall our findings demonstrate alterations of the myofilament proteins could contribute to fatigability of the SOL muscle and the decreased innate aerobic running performance of LCR compared with HCR rats.

Age-Related Outcomes in Total Ankle Arthroplasty: An Analysis of 112 Patients.

Traditionally, total ankle replacement has been reserved for elderly patients with low physical demands. With nearly 80% of end-stage ankle arthritis being secondary to prior trauma, patients may require a replacement at a much younger rate than primary hip and knee arthritis. Historical accounts of implant failure and high revision rates in younger patients have been reported in the literature. With increasing technology and surgeon experience, implants are being used in younger patients with significantly fewer complications than early reports. In this retrospective review, we evaluated the patient-reported outcome measures and implant complications in three age subsets in arthroplasty patients; Group 1: <55 years-old, Group 2: 55-70 years-old, and Group 3: >70 years-old. In our study, mean postoperative American Orthopedic Foot and Ankle Society (AOFAS) hindfoot scores were 75.5 for group 1, 79.7 for group 2, and 86.9 for group 3, which improved from preoperative scores of 50, 52.4, and 53.8, respectively. Mean postoperative Foot Function Index (FFI) scores were 10 for group 1, 23.9 for group 2, and 12.3 for group 3, which improved from 59.4, 62.8, and 47.6 preoperatively, respectively. The overall complication rate was found to be 11.2%. The complication rate for group 1 was 18%, the complication rate for group 2 was 11.6%, and the complication rate was 9.4% for group 3. The differences in patient AOFAS hindfoot, FFI scores, and complication rates between the groups were not found to be statistically significant. Our results show that patients younger than age 55 years have similar complication rates and reported satisfaction scores to patients 55 years of age and older.

Relationship Between Body Mass Index and Complications in Total Ankle Arthroplasty: A Single Surgeon's Experience in Ninety-Seven Replacements.

The purpose of this study was to compare complication rates of total ankle replacement in 2 groups of patients based on their body mass index (BMI). The total cohort was divided into 2 groups based on BMI. Group 1 included patients with a BMI ≤30 kg/m2. Group 2 included patients with a BMI >30 kg/m2. Available charts were reviewed for patients who underwent primary total ankle arthroplasty. Patient demographics, BMI, prosthesis used, concomitant procedures, and intraoperative and postoperative complications were recorded. Ninety-seven patients met the inclusion criteria and underwent total ankle replacement between March 2012 and July 2016. Mean follow-up was 26.3 (range 12 to 62) months. Mean age was 66.4 (range 23 to 85) years. Mean BMI was 29.6 (range 20.6 to 49.5) kg/m2. Forty-three males and 54 females were included. There were 53 patients in group 1 (BMI ≤30 kg/m2) and 44 patients in group 2 (BMI >30 kg/m2). Total complication rates for group 1 and 2 were 18.9% (10 of 53) and 11.4% (5 of 44), respectively. There were a total of 10 minor complications and 5 major complications. There was no statistical difference between the groups (p = .308) in terms of complication rates. All patients underwent at least 1 concomitant procedure at the time of the index ankle replacement. We found that total ankle replacement can be safely utilized in patients with a BMI >30 kg/m2. In the present study, there was no statistical significance in complication rates in the 2 groups.

A Critical Radiographic Analysis of Coronal Plane Deformity Correction Using a 3-Piece Mobile Bearing Ankle Joint Replacement: A Retrospective Study of 25 Patients.

Total ankle replacement can be a viable option for patients with end-stage ankle arthritis associated with coronal plane deformity. With proper ankle balancing, a well-aligned ankle implant can be maintained over time and provide successful patient outcomes. The purpose of this study was to evaluate radiographic and subjective outcomes in patients with ankle arthritis along with coronal plane deformity who underwent total ankle arthroplasty with a 3-piece mobile-bearing implant. Our primary inclusion criterion was patients who demonstrated more than 5° of tibiotalar coronal deformity in either varus or valgus direction. Sixty-three consecutive patients who underwent total ankle replacement were reviewed. Of these, 25 (39.7%) met the inclusion criteria. Sixteen (64%) patients had a varus deformity (Group 1) and 9 (36%) had valgus deformity (Group 2) preoperatively. Alignment was evaluated radiographically at 5 different intervals: preoperative, immediate postoperative, and 6, 12, and 36 months postoperative. In patients with varus deformity, the mean tibiotalar angle was 12.6°, 0.8°, 1.0°,1.0°, and 0.8° for preoperative, immediate postoperative, and 6, 12, and 36 months, respectively. The same measurements and intervals for patients with valgus deformity were found to be 10.3°, 1.4°, 1.6°, 1.4°, and 1.4°. A statistically significant difference was observed in preoperative and postoperative coronal plane deformity. This correction was maintained at final follow-up visit. American Orthopaedic Foot and Ankle Society scores and visual analogue scale scores were recorded as well, and statistically significant improvements in preoperative and postoperative scores were found (p < .001). In conclusion, coronal plane deformity correction of the ankle can be accomplished and maintained in total ankle replacement procedures with proper soft tissue balancing and osseous procedures as indicated.

Analysis of Two Different Arthroscopic Broström Repair Constructs for Treatment of Chronic Lateral Ankle Instability in 110 Patients: A Retrospective Cohort Study.

Chronic lateral ankle instability is a common condition treated by most foot and ankle surgeons. Once conservative treatment has failed, patients often undergo surgical reconstruction, either anatomic or nonanatomic. The present retrospective cohort study compared the clinical outcomes of 2 different arthroscopic Broström procedures. A total of 110 patients (83 females [75.5%] and 27 males [24.5%]) were treated with 1 of the 2 lateral ankle stabilization techniques from October 1, 2014 to December 31, 2015. Of the 110 patients, 75 were included in the arthroscopic lateral ankle stabilization group with an additional suture anchor used proximally and 35 were included in the arthroscopic lateral ankle stabilization group using the knotless design. The age of the cohort was 46.05 ± 17.89 (range 12 to 83) years. The body mass index was 30.03 ± 7.42 (range 18.3 to 52.5) kg/m2. Of the 110 patients, 25 (22.7%) had undergone concomitant procedures during lateral ankle stabilization. Overall, postoperative complications occurred in 14 patients (12.7%). No statistically significant differences were found between the 2 groups regarding the complication rates, use of concomitant procedures, and the presence of diabetes and workers compensation claims. No statistically significant differences were found in the mean age, body mass index, or gender distribution between the 2 groups. The preoperative American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scores were 50.85 ± 13.56 (range 18 to 76) and 51.26 ± 13.32 (range 18 to 69) in groups 1 and 2, respectively. The postoperative AOFAS Ankle-Hindfoot scores were 88.19 ± 10.72 (range 54 to 100) and 84 ± 15.41 (range 16 to 100) in groups 1 and 2, respectively. No statistically significant difference was found between these 2 groups. The preoperative visual analog scale score was 7.45 ± 1.39 (range 3 to 10) and 6.97 ± 1.25 (range 5 to 10), which had improved to 1.12 ± 1.38 (range 0 to 5) and 1.8 ± 1.98 (range 1 to 9) postoperatively for groups 1 and 2, respectively. The difference in the postoperative visual analog scale score between the 2 groups was statistically significant. The preoperative and postoperative AOFAS scale, Foot Function Index, and Karlsson-Peterson scores showed no statistically significant differences between the 2 groups. From our experience, either procedure is an acceptable treatment option for chronic lateral ankle instability, with the knotless technique showing a trend toward more complications.

A novel D2O tracer method to quantify RNA turnover as a biomarker of de novo ribosomal biogenesis, in vitro, in animal models, and in human skeletal muscle.

Current methods to quantify in vivo RNA dynamics are limited. Here, we developed a novel stable isotope (D2O) methodology to quantify RNA synthesis (i.e., ribosomal biogenesis) in cells, animal models, and humans. First, proliferating C2C12 cells were incubated in D2O-enriched media and myotubes ±50 ng/ml IGF-I. Second, rat quadriceps (untrained, n = 9; 7-wk interval-"like" training, n = 13) were collected after ~3-wk D2O (70 atom %) administration, with body-water enrichment monitored via blood sampling. Finally, 10 (23 ± 1 yr) men consumed 150-ml D2O followed by 50 ml/wk and undertook 6-wk resistance exercise (6 × 8 repetitions, 75% 1-repetition maximum 3/wk) with body-water enrichment monitored by saliva sampling and muscle biopsies (for determination of RNA synthesis) at 0, 3, and 6 wk. Ribose mole percent excess (r-MPE) from purine nucleotides was analyzed via GC-MS/MS. Proliferating C2C12 cell r-MPE exhibited a rise to plateau, whereas IGF-I increased myotube RNA from 76 ± 3 to 123 ± 3 ng/µl and r-MPE by 0.39 ± 0.1% (both P < 0.01). After 3 wk, rat quadriceps r-MPE had increased to 0.25 ± 0.01% (P < 0.01) and was greater with running exercise (0.36 ± 0.02%; P < 0.01). Human muscle r-MPE increased to 0.06 ± 0.01 and 0.13 ± 0.02% at 3/6 wk, respectively, equating to synthesis rates of ~0.8%/day, increasing with resistance exercise to 1.7 ± 0.3%/day (P < 0.01) and 1.2 ± 0.1%/day (P < 0.05) at 3/6 wk, respectively. Therefore, we have developed and physiologically validated a novel technique to explore ribosomal biogenesis in a multimodal fashion.

Gut microbiota are linked to increased susceptibility to hepatic steatosis in low-aerobic-capacity rats fed an acute high-fat diet.

Poor aerobic fitness is linked to nonalcoholic fatty liver disease and increased all-cause mortality. We previously found that rats with a low capacity for running (LCR) that were fed an acute high-fat diet (HFD; 45% kcal from fat) for 3 days resulted in positive energy balance and increased hepatic steatosis compared with rats that were highly aerobically fit with a high capacity for running (HCR). Here, we tested the hypothesis that poor physiological outcomes in LCR rats following acute HFD feeding are associated with alterations in cecal microbiota. LCR rats exhibited greater body weight, feeding efficiency, 3 days of body weight change, and liver triglycerides after acute HFD feeding compared with HCR rats. Furthermore, compared with HCR rats, LCR rats exhibited reduced expression of intestinal tight junction proteins. Cecal bacterial 16S rDNA revealed that LCR rats had reduced cecal Proteobacteria compared with HCR rats. Microbiota of HCR rats consisted of greater relative abundance of Desulfovibrionaceae and unassigned genera within this family, suggesting increased reduction of endogenous mucins and proteins. Although feeding rats an acute HFD led to reduced Firmicutes in both strains, short-chain fatty acid-producing Phascolarctobacterium was reduced in LCR rats. In addition, Ruminococcae and Ruminococcus were negatively correlated with energy intake in the LCR/HFD rats. Predicted metagenomic function suggested that LCR rats had a greater capacity to metabolize carbohydrate and energy compared with HCR rats. Overall, these data suggest that the populations and metabolic capacity of the microbiota in low-aerobically fit LCR rats may contribute to their susceptibility to acute HFD-induced hepatic steatosis and poor physiologic outcomes.

Evaluation of Hallux Valgus Correction With Versus Without Akin Proximal Phalanx Osteotomy.

Although the efficacy of Akin proximal phalanx closing wedge osteotomy as a sole procedure for correction of hallux valgus deformity is questionable, when used in combination with other osseous corrective procedures, the procedure has been believed to be efficacious. However, a limited number of comparative studies have confirmed the value of this additional procedure. We identified patients who had undergone osseous hallux valgus correction with first metatarsal osteotomy or first tarsometatarsal joint arthrodesis with (n = 73) and without (n = 81) Akin osteotomy and evaluated their radiographic measurements at 3 points (preoperatively, within 3 months after surgery, and ≥6 months after surgery). We found that those people who had undergone the Akin procedure tended to have a larger hallux abduction angle and a more laterally deviated tibial sesamoid position preoperatively. Although the radiographic correction of the deformity was promising immediately after corrective surgery with the Akin osteotomy, maintenance of the correction was questionable in our cohort. The value of additional Akin osteotomy for correction of hallux valgus deformity is uncertain.

Bluetongue disease in sheep in New South Wales - April 2023.

In 2016, bluetongue virus (BTV), serotype 16 (BTV-16), was detected in New South Wales (NSW) in sentinel cattle for the first time. Over the next 6 years, BTV-16 has been detected regularly and over an increasing area of the BTV zone in NSW. In April 2023, disease was reported in sheep on two farms on the Northern Tablelands of NSW. The consistent clinical signs included reduced exercise tolerance, facial swelling, serous nasal discharges with encrustation of the nasal plane, subcutaneous oedema of the neck and brisket and variable congestion of the coronary band. Affected sheep were mainly mature ewes and rams, with an estimated morbidity of 20% over a period of 6-8 weeks. Although there were several unexpected deaths, no veterinary examination was sought. Predominantly BTV-16 RNA was detected in sick sheep, with an incidence of infection of approximately 40% in a cross section of one flock. These events represent the first confirmation of disease due to bluetongue virus in NSW. As these cases occurred in a region with a high density of sheep, if there is ongoing transmission of BTV-16 during subsequent summers, further disease might be expected.

A gene related to Caenorhabditis elegans spermatogenesis factor fer-1 is mutated in limb-girdle muscular dystrophy type 2B.

The limb-girdle muscular dystrophies are a genetically heterogeneous group of inherited progressive muscle disorders that affect mainly the proximal musculature, with evidence for at least three autosomal dominant and eight autosomal recessive loci. The latter mostly involve mutations in genes encoding components of the dystrophin-associated complex; another form is caused by mutations in the gene for the muscle-specific protease calpain 3. Using a positional cloning approach, we have identified the gene for a form of limb-girdle muscular dystrophy that we previously mapped to chromosome 2p13 (LGMD2B). This gene shows no homology to any known mammalian gene, but its predicted product is related to the C. elegans spermatogenesis factor fer-1. We have identified two homozygous frameshift mutations in this gene, resulting in muscular dystrophy of either proximal or distal onset in nine families. The proposed name 'dysferlin' combines the role of the gene in producing muscular dystrophy with its C. elegans homology.

Immobilised teicoplanin does not demonstrate antimicrobial activity against Staphylococcus aureus.

Antibacterial bone biomaterial coatings appeal to orthopaedics, dentistry and veterinary medicine. Achieving the successful, stable conjugation of suitable compounds to biomaterial surfaces is a major challenge. A pragmatic starting point is to make use of existing, approved antibiotics which are known to remain functional in a stationary, immobilised state. This includes the macrocyclic glycopeptide, teicoplanin, following the discovery, in the 1990's, that it could be used as a chiral selector in chromatographic enantiomeric separations. Importantly teicoplanin works at the level of the bacterial cell wall making it a potential candidate for biomaterial functionalisations. We initially sought to functionalise titanium (Ti) with polydopamine and use this platform to capture teicoplanin, however we were unable to avoid the natural affinity of the antibiotic to the oxide surface of the metal. Whilst the interaction between teicoplanin and Ti was robust, we found that phosphate resulted in antibiotic loss. Before contemplating the covalent attachment of teicoplanin to Ti we examined whether a commercial teicoplanin stationary phase could kill staphylococci. Whilst this commercially available material could bind N-Acetyl-L-Lys-D-Ala-D-Ala it was unable to kill bacteria. We therefore strongly discourage attempts at covalently immobilising teicoplanin and/or other glycopeptide antibiotics in the pursuit of novel antibacterial bone biomaterials.

Osteoblast response to ovariectomy is enhanced in intrinsically high aerobic-capacity rats.

The role of exercise in promoting bone health is typically attributed to increased mechanical loading, which induces functional adaptation. Recent evidence suggests that habitual aerobic exercise has influence at the cellular level as well. The effect of aerobic capacity on osteoblast-lineage cell differentiation and function as well as skeletal phenotype is unknown. Using a rat model of high-capacity and low-capacity runners (HCRs and LCRs, respectively), in which an intrinsic functional genomic difference in aerobic capacity exists between nontrained animals, this study evaluated the effects of aerobic capacity on measures of bone mass and strength as well as osteoblast activity following ovariectomy. The ovariectomized rat emulates the clinical features of the estrogen-depleted human skeleton and represents a valuable model for studying short-term upregulation of osteoblast activity. We hypothesized that intrinsically high aerobic capacity would augment osteoblast response, which would mitigate the deleterious effects of hormone withdrawal. Femora and tibiae were assessed by micro-computed tomography, mechanical testing, and dynamic histomorphometry. HCRs had enhanced femoral tissue mineral density and estimated elastic modulus relative to LCRs. At 4 weeks postovariectomy, HCRs demonstrated a more robust osteoblast response. Markers of bone formation were upregulated to a greater extent in HCRs than LCRs, suggesting a role for aerobic capacity in governing osteoblast activity. Results from this and future studies will help to identify the influence of cellular aerobic metabolism on bone health, which may lead to new strategies for targeting diseases of the skeleton.

Constrained G4 structures unveil topology specificity of known and new G4 binding proteins.

G-quadruplexes (G4) are non-canonical secondary structures consisting in stacked tetrads of hydrogen-bonded guanines bases. An essential feature of G4 is their intrinsic polymorphic nature, which is characterized by the equilibrium between several conformations (also called topologies) and the presence of different types of loops with variable lengths. In cells, G4 functions rely on protein or enzymatic factors that recognize and promote or resolve these structures. In order to characterize new G4-dependent mechanisms, extensive researches aimed at identifying new G4 binding proteins. Using G-rich single-stranded oligonucleotides that adopt non-controlled G4 conformations, a large number of G4-binding proteins have been identified in vitro, but their specificity towards G4 topology remained unknown. Constrained G4 structures are biomolecular objects based on the use of a rigid cyclic peptide scaffold as a template for directing the intramolecular assembly of the anchored oligonucleotides into a single and stabilized G4 topology. Here, using various constrained RNA or DNA G4 as baits in human cell extracts, we establish the topology preference of several well-known G4-interacting factors. Moreover, we identify new G4-interacting proteins such as the NELF complex involved in the RNA-Pol II pausing mechanism, and we show that it impacts the clastogenic effect of the G4-ligand pyridostatin.

Regulation of antibody synthesis against Escherichia coli endotoxin. IV. Induction of paralysis in vitro by treating normal lymphoid cells with antigen.

Normal mouse lymphoid cells have been shown to become specifically paralyzed after in vitro exposure to high doses of detoxified endotoxin of Escherichia coli 055:B5. The immune status of the treated cells was tested after transfer to secondary irradiated hosts. Paralysis was shown to be initiated by events taking place in vitro, since the amount of antigen retained on the cells after the in vitro exposure was insufficient to induce paralysis in vivo. The induction of paralysis was dependent on the concentration of antigen added to the cells in vitro. Certain variables, such as time of exposure and temperature at exposure, influenced the ease by which the cells could be paralyzed. Cells pretreated with trypsin were not susceptible to induction of paralysis by the above procedure.

Experimental amyloidosis: the inducer is a polyclonal B-cell activator to which susceptibility is under genetic control.

Experimental amyloidosis in mice can be induced by repeated injections of casein. It has now been demonstrated that casein induces strong polyclonal antibody synthesis in mouse B spleen lymphocytes. This effect is much more pronounced in spleen cells from anyloid-susceptible mice (CBA/J) than amyloid-resistant mice (A/J). It is suggested that amyloidosis can be due in some instances to a constant exposure for molecules which induce polyclonal B-cell activation.

Frequencies of the separate human B cell subsets activatable to Ig secretion by Epstein-Barr virus and pokeweed mitogen.

We have developed a microculture system suitable for limiting dilution analysis of Epstein-Barr virus (EBV)- and pokeweed mitogen (PWM)-induced activation of immunoglobulin secretion by human B cells. It was found that exogenous filler cells were not required to obtain optimal EBV-induced B cell precursor frequency (PF) estimates, although filler T cells were required for optimal PWM activation. In fact, when autologous T cells were used as filler cells, a marked decrease in the EBV-induced IgM PF was noted. Treatment of the T cells with cyclosporin A partially eliminated, and irradiation of the T cells completely eliminated, this decrease. The calculated PF of B cells activated by EBV was from 1/290 to 1/3,700 for IgM, and from 1/920 to 1/3,250 for IgG secretion. PWM activated from 1/140 to 1/3,200 B cells to IgM secretion. The results of experiments in which EBV and PWM were mixed, indicated that these two polyclonal activators operated on different B cell subpopulations. Therefore, both these agents seem to activate small, discrete subpopulations of human peripheral blood B cells to Ig secretion.

Heterogeneity of the effector cells in the cytotoxic reaction against allogeneic lymphoma cells.

The cytotoxic effect of spleen cells from H-2 allogeneic mice was tested in vitro against an A strain leukemia (YAC) labeled with [(125)I]iododeoxyuridine. After the mice were primed with tumor cells, significant and specific H-2 immunity was detected on day 3 and peak cytotoxicity was observed between 7 and 14 days after priming. Two effector cells appear to be involved in the host response, because spleens taken from mice soon after priming were not sensitive to antitheta sera and complement while those taken during the peak stages of the response showed a marked reduction in cytotoxicity after treatment. Macrophages were not involved, since removal of these cells by the carbonyl iron method did not result in any reduction in cytotoxicity. Immune serum that was capable of inducing cell-mediated cytotoxicity in normal spleen cell populations also augmented cytotoxicity of spleen cells taken from mice primed 3 days previously. However, when spleen cells were taken from mice during the peak phase of the immune response, the same serum at the same dilutions inhibited the preexisting cytotoxicity. A difference was also detected in the killing efficiencies between early and late immune cells.

Characteristics of Epstein-Barr virus activation of human B lymphocytes.

Epstein-Barr virus (EBV) will infect at least every third cell if exposed in vitro to an extensively purified B cell population from human peripheral blood. About 10% of such infected cells will be driven into immunoglobulin synthesis and secretion, as judged by the indirect protein A plaque assay. The appearance of EB nuclear antigen, de novo DNA synthesis, and immunoglobulin secretion are linked phenomena accompanying infection as judged by viral dilution experiments, which yield kinetics of a one-hit order. Induction of immunoglobulin secretion in B cells by EBV requires de novo synthesis of DNA, and consequently, nontransforming EBV (P3HR1) will not induce immunoglobulin secretion and will also specifically block such induction from subsequently added EBV. The termination of immunoglobulin induction by EBV in short-term cultures appears to be T cell dependent.

The Effect of Tobacco Use on Incision Healing in Total Ankle Arthroplasty: A Review of 114 Patients.

The purpose of this study was to compare wound complication rates after total ankle replacement in 3 groups of patients based on tobacco status. The total cohort was divided into 3 groups based on tobacco history. Group 1 included patients who were actively tobacco users. Group 2 included patients with a history of tobacco user. Group 3 served as the control group and included patients who had never used tobacco. Available charts were reviewed for patients who underwent primary total ankle arthroplasty by 1 surgeon. Patient demographics, tobacco history, and postoperative wound complications were recorded. A total of 114 patients with tobacco history were available for follow-up and were included in this study, which ranged from March 2012 to July 2017. Group 1 included 11 active smokers. Group 2 included 38 former smokers, and group 3 had a total of 65 never smokers included. The average follow-up was 28 months for group 1 (range 10-55 months), 34.1 months for group 2 (range 12-60 months), and 32.8 months for group 3 (range 11-60 months). The wound complication rate was noted to be statistically significant when comparing active smokers to never smokers using Fisher's exact test (P = .0223). When comparing former smokers with never smokers, the difference in wound complication rate did not reach statistical significance (P = 0.7631). All patients underwent at least 1 concomitant procedure at the time of initial ankle replacement. Our findings show that total ankle replacement wound healing complication rates are significantly higher in active tobacco users. There was no significant difference in wound healing complications when comparing former tobacco users versus never tobacco users. Levels of Evidence: Level III: Retrospective comparative study.

Polymorphisms in Toll-like receptor 4 (TLR4) are associated with protection against leprosy.

Accumulating evidence suggests that polymorphisms in Toll-like receptors (TLRs) influence the pathogenesis of mycobacterial infections, including leprosy, a disease whose manifestations depend on host immune responses. Polymorphisms in TLR2 are associated with an increased risk of reversal reaction, but not susceptibility to leprosy itself. We examined whether polymorphisms in TLR4 are associated with susceptibility to leprosy in a cohort of 441 Ethiopian leprosy patients and 197 healthy controls. We found that two single nucleotide polymorphisms (SNPs) in TLR4 (896G>A [D299G] and 1196C>T [T399I]) were associated with a protective effect against the disease. The 896GG, GA and AA genotypes were found in 91.7, 7.8 and 0.5% of leprosy cases versus 79.9, 19.1 and 1.0% of controls, respectively (odds ratio [OR] = 0.34, 95% confidence interval [CI] 0.20-0.57, P < 0.001, additive model). Similarly, the 1196CC, CT and TT genotypes were found in 98.1, 1.9 and 0% of leprosy cases versus 91.8, 7.7 and 0.5% of controls, respectively (OR = 0.16, 95% CI 0.06--.40, P < 0.001, dominant model). We found that Mycobacterium leprae stimulation of monocytes partially inhibited their subsequent response to lipopolysaccharide (LPS) stimulation. Our data suggest that TLR4 polymorphisms are associated with susceptibility to leprosy and that this effect may be mediated at the cellular level by the modulation of TLR4 signalling by M. leprae.