Early radiographic and functional outcomes of a cancellous titanium-coated tibial component for total knee arthroplasty.

BACKGROUND: Various surface coatings have been developed over the past decades to enhance fixation of cementless total knee arthroplasty (TKA). BIOFOAM(®) (MicroPort Orthopedics Inc., Arlington, TN, USA) is a novel cancellous titanium surface coating intended to increase both initial and long-term fixation. The purpose of this study was to investigate the early functional and radiographic outcomes of this coating used in a TKA application. MATERIALS AND METHODS: One hundred and four (104) primary TKAs in 85 subjects using BIOFOAM-coated tibial components were prospectively enrolled at four centers. Subjects were evaluated using Knee Society Scores and radiographic analysis at a minimum follow-up of 24 months. RESULTS: Knee Society Scores and flexion were all significantly improved at final follow-up compared to baseline. Radiographic analyses were satisfactory, with no progressive radiolucencies and only a single subject presenting with a radiolucency surrounding a tibial component. There were two revisions in the cohort: one for instability following a ruptured lateral collateral ligament and one for recurrent tibial insert dislocation. CONCLUSIONS: This is the first study to report clinical outcomes associated with the BIOFOAM coating used in a cementless TKA application. Early functional scores and radiographic analyses are promising, but further investigations are needed to confirm long-term clinical success with these components.

Mid- to long-term outcomes of a medial-pivot system for primary total knee replacement: a systematic review and meta-analysis.

OBJECTIVES: This systematic review and meta-analysis was conducted to determine the mid- to long-term clinical outcomes for a medial-pivot total knee replacement (TKR) system. The objectives were to synthesise available survivorship, Knee Society Scores (KSS), and reasons for revision for this system. METHODS: A systematic search was conducted of two online databases to identify sources of survivorship, KSS, and reasons for revision. Survivorship results were compared with values in the National Joint Registry of England, Wales, and Northern Ireland (NJR). RESULTS: A total of eight studies that included data for 1146 TKRs performed in six countries satisfied the inclusion/exclusion criteria. Pooled component survivorship estimates were 99.2% (95% CI, 97.7 to 99.7) and 97.6% (95% CI, 95.8 to 98.6) at five and eight years, respectively. Survivorship was similar or better when compared with rates reported for all cemented TKRs combined in the NJR and was significantly better than some insert types at mid-term intervals. The weighted mean post-operative KSS was 87.9 (73.2 to 94.2), in the excellent range. Similar cumulative revision rates and KSS were reported at centres in the United States, Europe, and Asia. CONCLUSIONS: The subject system was associated with survivorship and KSS similar or better than that reported for other TKR systems. Cite this article: Bone Joint Res 2014;3:297-304.

The reproducibility of organ position using active breathing control (ABC) during liver radiotherapy.

PURPOSE: To evaluate the intrafraction and interfraction reproducibility of liver immobilization using active breathing control (ABC). METHODS AND MATERIALS: Patients with unresectable intrahepatic tumors who could comfortably hold their breath for at least 20 s were treated with focal liver radiation using ABC for liver immobilization. Fluoroscopy was used to measure any potential motion during ABC breath holds. Preceding each radiotherapy fraction, with the patient setup in the nominal treatment position using ABC, orthogonal radiographs were taken using room-mounted diagnostic X-ray tubes and a digital imager. The radiographs were compared to reference images using a 2D alignment tool. The treatment table was moved to produce acceptable setup, and repeat orthogonal verification images were obtained. The positions of the diaphragm and the liver (assessed by localization of implanted radiopaque intra-arterial microcoils) relative to the skeleton were subsequently analyzed. The intrafraction reproducibility (from repeat radiographs obtained within the time period of one fraction before treatment) and interfraction reproducibility (from comparisons of the first radiograph for each treatment with a reference radiograph) of the diaphragm and the hepatic microcoil positions relative to the skeleton with repeat breath holds using ABC were then measured. Caudal-cranial (CC), anterior-posterior (AP), and medial-lateral (ML) reproducibility of the hepatic microcoils relative to the skeleton were also determined from three-dimensional alignment of repeat CT scans obtained in the treatment position. RESULTS: A total of 262 fractions of radiation were delivered using ABC breath holds in 8 patients. No motion of the diaphragm or hepatic microcoils was observed on fluoroscopy during ABC breath holds. From analyses of 158 sets of positioning radiographs, the average intrafraction CC reproducibility (sigma) of the diaphragm and hepatic microcoil position relative to the skeleton using ABC repeat breath holds was 2.5 mm (range 1.8-3.7 mm) and 2.3 mm (range 1.2-3.7 mm) respectively. However, based on 262 sets of positioning radiographs, the average interfraction CC reproducibility (sigma) of the diaphragm and hepatic microcoils was 4.4 mm (range 3.0-6.1 mm) and 4.3 mm (range 3.1-5.7 mm), indicating a change of diaphragm and microcoil position relative to the skeleton over the course of treatment with repeat breath holds at the same phase of the respiratory cycle. The average population absolute intrafraction CC offset in diaphragm and microcoil position relative to skeleton was 2.4 mm and 2.1 mm respectively; the average absolute interfraction CC offset was 5.2 mm. Analyses of repeat CT scans demonstrated that the average intrafraction excursion of the hepatic microcoils relative to the skeleton in the CC, AP, and ML directions was 1.9 mm, 0.6 mm, and 0.6 mm respectively and the average interfraction CC, AP, and ML excursion of the hepatic microcoils was 6.6 mm, 3.2 mm, and 3.3 mm respectively. CONCLUSION: Radiotherapy using ABC for patients with intrahepatic cancer is feasible, with good intrafraction reproducibility of liver position using ABC. However, the interfraction reproducibility of organ position with ABC suggests the need for daily on-line imaging and repositioning if treatment margins smaller than those required for free breathing are a goal.

Rearrangement of immunoglobulin genes in shark germ cells.

The variable (V), (diversity [D]), and joining (J) region recombinases (recombination activating genes [RAGs]) can perform like transposases and are thought to have initiated development of the adaptive immune system in early vertebrates by splitting archaic V genes with transposable elements. In cartilaginous fishes, the immunoglobulin (Ig) light chain genes are organized as multiple VJ-constant (C) clusters; some loci are capable of rearrangement while others contain fused VJ. The latter may be key to understanding the evolutionary role of RAG. Are they relics of the archaic genes, or are they results of rearrangement in germ cells? Our data suggest that some fused VJ genes are not only recently rearranged, but also resulted from RAG-like activity involving hairpin intermediates. Expression studies show that these, like some other germline-joined Ig sequences, are expressed at significant levels only early in ontogeny. We suggest that a rejoined Ig gene may not merely be a sequence restricting antibody diversity, but is potentially a novel receptor no longer tied to somatic RAG expression and rearrangement. From the combined data, we arrived at the unexpected conclusion that, in some vertebrates, RAG is still an active force in changing the genome.

Accessing restoration margins--a multidisciplinary approach.

Dentists frequently balance periodontal, restorative, and esthetic concerns that will provide adequate tooth length, ensure periodontal health, and provide biological predictability. This report discusses the current and classical literature and provides a multidisciplinary approach of predictably "accessing" the restoration margins to facilitate long-term gingival health and tooth survival.

Evolution of "rhabditidae" and the male tail.

Evolution of diverse male tail epidermal features of representative species in the family Rhabditidae (Nematoda:Rhabditida) was mapped by parsimony on a molecular phylogeny inferred with nearly complete DNA sequences of small subunit ribosomal RNA genes. Although the molecular phylogeny is consistent with some previously proposed relationships, there are also some major differences, suggesting a revision of rhabditid taxonomy is required. To reconstruct male tail evolution, character states and homologies were determined with the aid of developmental profiling at the level of single cells. Because the model genetic system Caenorhabditis elegans is a member of Rhabditidae and allows the genetic and developmental mechanisms of morphogenesis to be elucidated, candidate genes and pathways can be proposed for several of the reconstructed evolutionary changes in male tail morphology.

Morphogenesis of the Caenorhabditis elegans male tail tip.

Using electron microscopy and immunofluorescent labeling of adherens junctions, we have reconstructed the changes in cell architecture and intercellular associations that occur during morphogenesis of the nematode male tail tip. During late postembryonic development, the Caenorhabditis elegans male tail is reshaped to form a copulatory structure. The most posterior hypodermal cells in the tail define a specialized, sexually dimorphic compartment in which cells fuse and retract in the male, changing their shape from a tapered cone to a blunt dome. Developmental profiles using electron microscopy and immunofluorescent staining suggest that cell fusions are initiated at or adjacent to adherens junctions. Anterior portions of the tail tip cells show the first evidence of retractions and fusions, consistent with our hypothesis that an anterior event triggers these morphogenetic events. Available mutations that interfere with morphogenesis implicate particular regulatory pathways and suggest loci at which evolutionary changes could have produced morphological diversity.

Evolution of male tail development in rhabditid nematodes related to Caenorhabditis elegans.

The evolutionary pathway that has led to male tails of diverse morphology among species of the nematode family Rhabditidae was reconstructed. This family includes the well-studied model species Caenorhabditis elegans. By relating the steps of male tail morphological evolution to the phenotypic changes brought about by developmental mutations induced experimentally in C. elegans, the goal is to identify genes responsible for morphological evolution. The varying morphological characters of the male tails of several rhabiditid species have been described previously (Fitch and Emmons, 1995, Dev. Biol. 170:564-582). The developmental events preceding differentiation of the adult structures have also been analyzed; in many cases the origins of varying adult morphological characters were traced to differences during ontogeny. In the present work, the evolutionary changes producing these differences were reconstructed in the context of the four possible phylogenies supported independently by sequences of 18S ribosomal RNA genes (rDNA). Two or more alternative states were defined for 36 developmental and adult morphological characters. These characters alone do not provide sufficient data to resolve most species relationships; however, when combined with the rDNA characters, they provide stronger support for one of the four rDNA phylogenies. Assuming a model of ordered transformations for multistate developmental characters generally results in greater resolution. Transformations between character states can be assigned unequivocally by parsimony to unambiguous branches for most of the characters. Correlations are thereby revealed for some of the developmental characters, indicating a probability of a shared developmental or genetic regulatory pathway. Four of the unequivocal character state changes on unambiguously supported branches closely resemble the phenotypic changes brought about by known mutations in C. elegans. These mutations define genes that are known to act in genetic regulatory hierarchies controlling pattern formation, differentiation, and morphogenesis. Although these studies are still at an early stage, these results strongly suggest that parallel studies of developmental mutants in C. elegans and of morphological and developmental evolution among related nematodes will help define genetic changes underlying the evolution of form.

Variable cell positions and cell contacts underlie morphological evolution of the rays in the male tails of nematodes related to Caenorhabditis elegans.

As a first step toward understanding their mechanism of morphological evolution, we compare the morphology and development of the male genitalia in 10 species of Rhabditidae, the family of nematodes that includes Caenorhabditis elegans. We describe a number of variable morphological characteristics and focus in particular on the differing arrangements of the caudal papillae or rays within the acellular fan. We analyze the development of the ray cells within the epidermis of the last larval stage and identify changes in cell positions and cell contacts that underlie evolutionary changes in the arrangement of the rays. Epidermal cell positions were determined by means of indirect immunofluorescence staining with a monoclonal antibody directed towards adherens junctions. Similarities between the species in the cellular arrangements during the earliest developmental stages allow us to propose homologies between the rays in different species. Evolutionary changes in the positions and order of homologous rays are correlated with shifts in cell positions during development. The results suggest that genes for cell recognition or adhesion proteins, or pattern formation genes that regulate cell recognition or adhesion proteins, may be important foci of evolutionary change affecting morphology.

18S ribosomal RNA gene phylogeny for some Rhabditidae related to Caenorhabditis.

We have investigated the molecular evolution of the nucleotide sequences of 18S ribosomal RNA genes (18S rDNA) from a set of nematodes in the family Rhabditidae (Nematoda: Secernentea). Our aim was to evaluate the usefulness of this gene for molecular systematics of this family, as well as to establish phylogenetic relationships within a group that has potential for comparative studies of the relationship between development and evolution. We determined the 18S rDNA sequences of nine species of nematodes representing six genera within this family (Caenorhabditis briggsae, C. vulgaris, C. remanei, Rhabditis blumi, Rhabditis sp. br, Rhabditella axei, Pellioditis typica. Teratorhabditis palmarum, and Pelodera strongyloides dermatitica). Using hypothetical models for secondary structure as well as nucleotide similarity, these sequences were aligned with the 18S rDNA sequence published by Ellis et al. for C. elegans and with the partial sequences published by Nadler for eight ascaridoid species. We find that 18S rDNA is likely to be a useful tool to resolve relationships at the intrafamilial level. However, 18S rDNA sequences cannot be used to resolve relationships between taxa as closely related as the Caenorhabditis species. Parsimony, minimum-evolution, and maximum-likelihood methods strongly reject Andrássy's proposed phylogenetic classification based on adult morphological characters but support that of Sudhaus as one alternative of a few possible phylogenies. Distances between genera in this family are about eight times as great as distances between tetrapod classes, suggesting rapid rates of substitution, ancient divergence, or both.

Widespread occurrence of the Tc1 transposon family: Tc1-like transposons from teleost fish.

We characterized five transposable elements from fish: one from zebrafish (Brachydanio rerio), one from rainbow trout (Salmo gairdneri), and three from Atlantic salmon (Salmo salar). All are closely similar in structure to the Tc1 transposon of the nematode Caenorhabditis elegans. A comparison of 17 Tc1-like transposons from species representing three phyla (nematodes, arthropods, and chordates) showed that these elements make up a highly conserved transposon family. Most are close to 1.7 kb in length, have inverted terminal repeats, have conserved terminal nucleotides, and each contains a single gene encoding similar polypeptides. The phylogenetic relationships of the transposons were reconstructed from the amino acid sequences of the conceptual proteins and from DNA sequences. The elements are highly diverged and have evidently inhibited the genomes of these diverse species for a long time. To account for the data, it is not necessary to invoke recent horizontal transmission.

Shared governance and imaging: "pyramid power" revisited.

Shared governance is a concept that is gaining wide acceptance in the United States; however, it is still in its infancy in Canada. This article introduces shared governance principles to diagnostic imaging administrators and staff and informs them of the rationale, benefits and challenges of this management philosophy. In addition, the implementation of an imaging department empowerment program will be explored, as will its relationship to a facility-wide shared governance program.

Survey of sterile product compounding practices in Canadian hospital pharmacies.

Improper preparation of sterile products by hospital or community pharmacies may have serious consequences. Recent reports of deaths or injury to patients as a result of receiving products that were contaminated during their preparation in a pharmacy have highlighted the importance of maintaining good sterile compounding practices. Efforts are now underway to develop revised guidelines for the compounding of sterile products in order to minimize the potential for future recurrence of similar incidents. This survey study was undertaken to provide background data on current sterile products compounding practices and procedures in Canadian hospital pharmacies. It was also anticipated that these data would be helpful in identifying issues that needed to be addressed in the new guidelines. Surveys were distributed to 700 Canadian hospitals with 50 or more beds. Responses from returned surveys were entered into and analyzed using the database program RBase. A total of 306 hospital pharmacies responded, with 200 indicating that sterile products were compounded within their department. The information provided by respondents provides insight into the types of sterile products being prepared in Canadian hospitals, the training background of staff involved in sterile product preparation, the type of facilities and equipment used for compounding these preparations, and the quality control/quality assurance procedures that are in place in hospital pharmacies. The information arising from this survey underscores the need for comprehensive guidelines or standards with respect to sterile product compounding, and the need for improved training of personnel involved in sterile product compounding. The results should be of interest to hospital pharmacy administrators, pharmacy regulatory bodies, and government agencies responsible for assuring the safety of pharmaceutical products used in patient care.

Low codon bias and high rates of synonymous substitution in Drosophila hydei and D. melanogaster histone genes.

We have evaluated codon usage bias in Drosophila histone genes and have obtained the nucleotide sequence of a 5,161-bp D. hydei histone gene repeat unit. This repeat contains genes for all five histone proteins (H1, H2a, H2b, H3, and H4) and differs from the previously reported one by a second EcoRI site. These D. hydei repeats have been aligned to each other and to the 5.0-kb (i.e., long) and 4.8-kb (i.e., short) histone repeat types from D. melanogaster. In each species, base composition at synonymous sites is similar to the average genomic composition and approaches that in the small intergenic spacers of the histone gene repeats. Accumulation of synonymous changes at synonymous sites after the species diverged is quite high. Both of these features are consistent with the relatively low codon usage bias observed in these genes when compared with other Drosophila genes. Thus, the generalization that abundantly expressed genes in Drosophila have high codon bias and low rates of silent substitution does not hold for the histone genes.

Syncope in military formations: a persistent problem.

Syncope of personnel standing in ranks during a military ceremony is an all too common occurrence. An episode of syncope can have serious and sometimes long-lasting medical consequences in addition to disrupting the ceremony and causing embarrassment for the individual involved. This article will discuss the pathophysiology and contributing factors, common injuries which can result, immediate on-scene treatment, and recommendations as to how this phenomenon might be prevented.

A multicenter, double-blind, randomized, placebo-controlled comparison of nocturnal roxatidine in the treatment of active duodenal ulcer disease. Multicenter Roxatidine Cooperative Study Group.

This multicenter randomized, double-blind, 4-wk study compared the new H2-receptor antagonistic roxatidine (R) to placebo (P) for treatment of endoscopically diagnosed active duodenal ulcer disease. Subjects were evaluated after 2 and 4 wk of treatment. Those whose ulcer was unhealed at 2 wk received 2 more weeks of treatment before final evaluation. Ulcer healing (endoscopically determined) with roxatidine was more effective than placebo at both wk 0-2 (R = 33.9%, P = 21.9%, p = 0.018) and wk 2-4 (R = 68.2%, P = 29.7%, p less than 0.001), with an overall 4-wk effectiveness of 78.9% compared to 44.8% (p less than 0.001). At the end of treatment, average maximum ulcer diameter diminished 83% in R and 50% in P (p less than 0.001). Roxatidine was also more effective than placebo in decreasing abdominal pain (p less than 0.001), decreasing the number of antacid tablets taken for pain relief (p less than 0.001), improving dyspeptic symptoms (p less than 0.001), and permitting return to a normal routine for subjects with previous illness-imposed restrictions on work and/or other daily activities. The profile of laboratory values and adverse experiences demonstrated roxatidine to be safe and well-tolerated. The efficacy of roxatidine as evaluated by the healing rate of duodenal ulcer and reduction in abdominal pain emphasize its value as an addition to the family of H2-receptor antagonists.