Causes of instability after total knee arthroplasty.

The purpose of the present study was to characterize the underlying causes that lead to instability after total knee arthroplasty (TKA). We reviewed 83 revision TKAs (79 patients) performed for instability. After detailed analysis of patient's history, physical examination, operative report and radiographs, we identified six categories: flexion/extension gap mismatch, component malposition, isolated ligament insufficiency, extensor mechanism insufficiency, component loosening, and global instability.

Rapid and accurate large-scale genotyping of duplicated genes and discovery of interlocus gene conversions.

Over 900 genes have been annotated within duplicated regions of the human genome, yet their functions and potential roles in disease remain largely unknown. One major obstacle has been the inability to accurately and comprehensively assay genetic variation for these genes in a high-throughput manner. We developed a sequencing-based method for rapid and high-throughput genotyping of duplicated genes using molecular inversion probes designed to target unique paralogous sequence variants.

Rates and patterns of great ape retrotransposition.

We analyzed 83 fully sequenced great ape genomes for mobile element insertions, predicting a total of 49,452 fixed and polymorphic Alu and long interspersed element 1 (L1) insertions not present in the human reference assembly and assigning each retrotransposition event to a different time point during great ape evolution. We used these homoplasy-free markers to construct a mobile element insertions-based phylogeny of humans and great apes and demonstrate their differential power to discern ape subspecies and populations. Within this context, we find a good correlation between L1 diversity and single-nucleotide polymorphism heterozygosity (r(2) = 0.

Imprinted chromatin around DIRAS3 regulates alternative splicing of GNG12-AS1, a long noncoding RNA.

Imprinted gene clusters are regulated by long noncoding RNAs (lncRNAs), CCCTC binding factor (CTCF)-mediated boundaries, and DNA methylation. DIRAS3 (also known as ARH1 or NOEY1) is an imprinted gene encoding a protein belonging to the RAS superfamily of GTPases and is located within an intron of a lncRNA called GNG12-AS1. In this study, we investigated whether GNG12-AS1 is imprinted and coregulated with DIRAS3.

A mutational analysis of active site residues in trans-3-chloroacrylic acid dehalogenase.

trans-3-Chloroacrylic acid dehalogenase (CaaD) catalyzes the hydrolytic dehalogenation of trans-3-haloacrylates to yield malonate semialdehyde by a mechanism utilizing βPro-1, αArg-8, αArg-11, and αGlu-52. These residues are implicated in a promiscuous hydratase activity where 2-oxo-3-pentynoate is processed to acetopyruvate. The roles of three nearby residues (βAsn-39, αPhe-39, and αPhe-50) are unexplored.

Evolution and diversity of copy number variation in the great ape lineage.

Copy number variation (CNV) contributes to disease and has restructured the genomes of great apes. The diversity and rate of this process, however, have not been extensively explored among great ape lineages. We analyzed 97 deeply sequenced great ape and human genomes and estimate 16% (469 Mb) of the hominid genome has been affected by recent CNV.

A mutational analysis of the active site loop residues in cis-3-Chloroacrylic acid dehalogenase.

cis-3-Chloroacrylic acid dehalogenase (cis-CaaD) from Pseudomonas pavonaceae 170 and a homologue from Corynebacterium glutamicum designated Cg10062 are 34% identical in sequence (54% similar). The former catalyzes a key step in a bacterial catabolic pathway for the nematocide 1,3-dichloropropene, whereas the latter has no known biological activity. Although Cg10062 has the six active site residues (Pro-1, His-28, Arg-70, Arg-73, Tyr-103, and Glu-114) that are critical for cis-CaaD activity, it shows only a low level cis-CaaD activity and lacks the specificity of cis-CaaD: Cg10062 processes both isomers of 3-chloroacrylate with a preference for the cis isomer.

Nonhybrid, finished microbial genome assemblies from long-read SMRT sequencing data.

We present a hierarchical genome-assembly process (HGAP) for high-quality de novo microbial genome assemblies using only a single, long-insert shotgun DNA library in conjunction with Single Molecule, Real-Time (SMRT) DNA sequencing. Our method uses the longest reads as seeds to recruit all other reads for construction of highly accurate preassembled reads through a directed acyclic graph-based consensus procedure, which we follow with assembly using off-the-shelf long-read assemblers. In contrast to hybrid approaches, HGAP does not require highly accurate raw reads for error correction.

Natural transformation as a mechanism of horizontal gene transfer among environmental Aeromonas species.

Aeromonas species are common inhabitants of aquatic environments and relevant as human pathogens. Their potential as pathogens may be related in part to lateral transfer of genes associated with toxin production, biofilm formation, antibiotic resistance, and other virulence determinants. Natural transformation has not been characterized in aeromonads.

Complete haplotype sequence of the human immunoglobulin heavy-chain variable, diversity, and joining genes and characterization of allelic and copy-number variation.

The immunoglobulin heavy-chain locus (IGH) encodes variable (IGHV), diversity (IGHD), joining (IGHJ), and constant (IGHC) genes and is responsible for antibody heavy-chain biosynthesis, which is vital to the adaptive immune response. Programmed V-(D)-J somatic rearrangement and the complex duplicated nature of the locus have impeded attempts to reconcile its genomic organization based on traditional B-lymphocyte derived genetic material. As a result, sequence descriptions of germline variation within IGHV are lacking, haplotype inference using traditional linkage disequilibrium methods has been difficult, and the human genome reference assembly is missing several expressed IGHV genes.

MI TKA: a risk factor for early revision surgery.

Minimal incision total knee arthroplasty (MI TKA) was developed with the potential to decrease surgical trauma, pain, and recovery time. While this procedure has increased in popularity, some surgeons have questioned its safety and long-term efficacy. In this study 58 consecutive revision total knee arthroplasties (TKAs) (57 patients) performed at one academic medical center from 2006 to 2008 are reviewed.

Myocardial infarction after hip fracture repair: a population-based study.

Objectives: To quantify the occurrence of myocardial infarction (MI) occurring in the early postoperative period after surgical hip fracture repair and estimate the effect on 1-year mortality.

Design: A population-based, historical cohort study of individuals who underwent surgical repair of a hip fracture that used the computerized medical record linkage system of the Rochester Epidemiology Project.

Setting: Academic and community hospitals, outpatient offices, and nursing homes in Olmsted County, Minnesota.

A pre-steady state kinetic analysis of the αY60W mutant of trans-3-chloroacrylic acid dehalogenase: implications for the mechanism of the wild-type enzyme.

The bacterial degradation of the nematicide 1,3-dichloropropene, an isomeric mixture, requires the action of trans- and cis-3-chloroacrylic acid dehalogenase (CaaD and cis-CaaD, respectively). Both enzymes are tautomerase superfamily members and share a core catalytic mechanism for the hydrolytic dehalogenation of the respective isomer of 3-haloacrylate. The observation that cis-CaaD requires two additional residues raises the question of how CaaD conducts a comparable reaction with fewer catalytic residues.

Clinical presentation and outcome of perioperative myocardial infarction in the very elderly following hip fracture surgery.

Background: Patterns of clinical symptoms and outcomes of perioperative myocardial infarction (PMI) in elderly patients after hip fracture repair surgery are not well defined.

Methods: A retrospective 1:2 case-control study in a cohort of 1212 elderly patients undergoing hip fracture surgery from 1988 to 2002 in Olmsted County, Minnesota.

Results: The mean age was 85.

Methylation by a unique α-class N4-cytosine methyltransferase is required for DNA transformation of Caldicellulosiruptor bescii DSM6725.

Thermophilic microorganisms capable of using complex substrates offer special advantages for the conversion of lignocellulosic biomass to biofuels and bioproducts. Members of the gram-positive bacterial genus Caldicellulosiruptor are anaerobic thermophiles with optimum growth temperatures between 65°C and 78°C and are the most thermophilic cellulolytic organisms known. In fact, they efficiently use biomass non-pretreated as their sole carbon source and in successive rounds of application digest 70% of total switchgrass substrate.

Commentary: Is the hip bone connected to the spine bone?

Prather H, Van Dillen LR, Kymes SM, et al. Impact of coexistent lumbar spine disorders on clinical outcomes and physician charges associated with total hip arthroplasty. Spine J 2012;12:363-9 (in this issue).

Nutrition, weight gain and eating behavior in pregnancy: a review of experimental evidence for long-term effects on the risk of obesity in offspring.

Obesity has reached near epidemic proportions in the developed world. As reproductive age women are a part of this trend, the effect of maternal obesity on the developing fetus must be investigated. In this review, we evaluated the experimental evidence relating maternal nutritional status and eating behavior before and during pregnancy on the risk of obesity in the offspring.

Heparin-induced thrombocytopenia after total knee arthroplasty, with subsequent adrenal hemorrhage.

Heparin-induced thrombocytopenia (HIT) is a life-threatening immune-mediated adverse effect of chemoprophylaxis for venous thromboembolic events. We present the case of a 44-year-old man who developed bilateral adrenal hemorrhage (BAH) as a sequela of HIT after bilateral total knee arthroplasty. In our review of clinical management of HIT-induced BAH, we discuss the 21 published cases of this phenomenon, 14 of which occurred after orthopedic surgery.

Mapping late testers for HIV in Texas.

Understanding the spatial patterns of late testing for HIV infection is critically important for designing and evaluating intervention strategies to reduce the social and economic burdens of HIV/AIDS. Traditional mapping methods that rely on frequency counts or rates in predefined areal units are known to be problematic due to issues of small numbers and visual biases. Additionally, confidentiality requirements associated with health data further restrict the ability to produce cartographic representations at fine geographic scales.

Advanced age and comorbidity increase the risk for adverse events after revision total hip arthroplasty.

With the institution of quality-assurance parameters in health care, physicians must accurately measure and report the true baseline rates of adverse events (AEs) after complex surgical interventions. To better quantify the risk of AEs for revision total hip arthroplasty (THA), we divided a cohort of 306 patients (322 procedures) into age groups: group I (<65 years, n = 138), group II (65-79 years, n = 119), and group III (≥80 years, n = 65). Ninety-day rates of major AE were 9%, 19%, and 34% in the groups, respectively.

Reaction of cis-3-chloroacrylic acid dehalogenase with an allene substrate, 2,3-butadienoate: hydration via an enamine.

cis-3-Chloroacrylic acid dehalogenase (cis-CaaD) catalyzes the hydrolytic dehalogenation of cis-3-haloacrylates to yield malonate semialdehyde. The enzyme processes other substrates including an allene (2,3-butadienoate) to produce acetoacetate. In the course of a stereochemical analysis of the cis-CaaD-catalyzed reaction using this allene, the enzyme was unexpectedly inactivated in the presence of NaBH(4) by the reduction of a covalent enzyme-substrate bond.

Impact of heart failure on hip fracture outcomes: a population-based study.

Background: Hip fracture and heart failure are becoming more prevalent conditions in hospitalized patients. Despite differences in postoperative outcomes from other intermediate risk procedures, guidelines classify hip fracture repair as an intermediate risk operation.

Objective: This population-based study sought to examine the prevalence and incidence of heart failure in hip fracture patients.