A nomogram to determine required seed air kerma strength in planar 131 Cesium permanent seed implant brachytherapy

Purpose: Intraoperatively implanted Cesium-131 ( 131 Cs) permanent seed brachytherapy is used to deliver highly localized re-irradiation in recurrent head and neck cancers. A single planar implant of uniform air kerma strength (AKS) seeds and 10 mm seed-to-seed spacing is used to deliver the prescribed dose to a point 5 mm or 10 mm perpendicular to the center of the implant plane. Nomogram tables to quickly determine the required AKS for rectangular and irregularly shaped implants were created and dosimetrically verified. By eliminating the need for a full treatment planning system plan, nomogram tables allow for fast dose calculation for intraoperative re-planning and for a second check method. Material and methods: TG-43U1 recommended parameters were used to create a point-source model in MATLAB. The dose delivered to the prescription point from a single 1 U seed at each possible location in the implant plane was calculated. Implant tables were verified using an independent seed model in MIM Symphony LDR™. Implant tables were used to retrospectively determine seed AKS for previous cases: three rectangular and three irregular. Results: For rectangular implants, the percent difference between required seed AKS calculated using MATLAB and MIM was at most 0.6%. For irregular implants, the percent difference between MATLAB and MIM calculations for individual seed locations was within 1.5% with outliers of less than 3.1% at two distal locations (10.6 cm and 8.8 cm), which have minimal dose contribution to the prescription point. The retrospectively determined AKS for patient implants using nomogram tables agreed with previous calculations within 5% for all six cases. Conclusions: Nomogram tables were created to determine required AKS per seed for planar uniform AKS 131 Cs implants. Comparison with the treatment planning system confirms dosimetric accuracy that is acceptable for use as a second check or for dose calculation in cases of intraoperative re-planning

The Dfam community resource of transposable element families, sequence models, and genome annotations.

Dfam is an open access database of repetitive DNA families, sequence models, and genome annotations. The 3.0-3.3 releases of Dfam ( https://dfam.org ) represent an evolution from a proof-of-principle collection of transposable element families in model organisms into a community resource for a broad range of species, and for both curated and uncurated datasets. In addition, releases since Dfam 3.0 provide auxiliary consensus sequence models, transposable element protein alignments, and a formalized classification system to support the growing diversity of organisms represented in the resource. The latest release includes 266,740 new de novo generated transposable element families from 336 species contributed by the EBI. This expansion demonstrates the utility of many of Dfam\u27s new features and provides insight into the long term challenges ahead for improving de novo generated transposable element datasets

PiggyBac-ing on a Primate Genome: Novel Elements, Recent Activity and Horizontal Transfer

To better understand the extent of Class II transposable element activity in mammals, we investigated the mouse lemur, Microcebus murinus, whole genome shotgun (2X) draft assembly. Analysis of this strepsirrhine primate extended previous research that targeted anthropoid primates and found no activity within the last 37 Myr. We tested the hypothesis that members of the piggyBac Class II superfamily have been inactive in the strepsirrhine lineage of primates during the same period. Evidence against this hypothesis was discovered in the form of three nonautonomous piggyBac elements with activity periods within the past 40 Myr and possibly into the very recent past. In addition, a novel family of piggyBac transposons was identified, suggesting introduction via horizontal transfer. A second autonomous element was also found with high similarity to an element recently described from the little brown bat, Myotis lucifugus, further implicating horizontal transfer in the evolution of this genome. These findings indicate a more complex history of transposon activity in mammals rather than a uniform shutdown of Class II transposition, which had been suggested by analyses of more common model organisms

The feasibility of measuring the activation of the trunk muscles in healthy older adults during trunk stability exercises

<p>Abstract</p> <p>Background</p> <p>As the older adult population increases, the potential functional and clinical burden of trunk muscle dysfunction may be significant. An evaluation of risk factors including the impact of the trunk muscles in terms of their temporal firing patterns, amplitudes of activation, and contribution to spinal stability is required. Therefore, the specific purpose of this study was to assess the feasibility of measuring the activation of trunk muscles in healthy older adults during specific leg exercises with trunk stabilization.</p> <p>Methods</p> <p>12 asymptomatic adults 65 to 75 years of age were included in the study. Participants performed a series of trunk stability exercises, while bilateral activation of abdominal and back extensor muscles was recorded by 24 pairs of Meditrace™ surface electrodes. Maximal voluntary isometric contractions (MVIC) were performed for electromyographic (EMG) normalization purposes. EMG waveforms were generated and amplitude measures as a percentage of MVIC were calculated along with ensemble average profiles. 3D kinematics data were also recorded, using an electromagnetic sensor placed at the left lateral iliac crest. Furthermore, a qualitative assessment was conducted to establish the participant's ability to complete all experimental tasks.</p> <p>Results</p> <p>Excellent quality abdominal muscle activation data were recorded during the tasks. Participants performed the trunk stability exercises with an unsteady, intermittent motion, but were able to keep pelvic motion to less than 10°. The EMG amplitudes showed that during these exercises, on average, the older adults recruited their abdominal muscles from 15–34% of MVIC and back extensors to less than 10% of MVIC. There were similarities among the abdominal muscle profiles. No participants reported pain during the testing session, although 3 (25%) of the participants reported delayed onset muscle soreness during follow up that was not functionally limiting.</p> <p>Conclusion</p> <p>Older adults were able to successfully complete the trunk stability protocol that was developed for younger adults with some minor modifications. The collected EMG amplitudes were higher than those reported in the literature for young healthy adults. The temporal waveforms for the abdominal muscles showed a degree of synchrony among muscles, except for the early activation from the internal oblique prior to lifting the leg off the table.</p

Mobile DNA in Old World monkeys: A glimpse through the rhesus macaque genome

The completion of the draft sequence of the rhesus macaque genome allowed us to study the genomic composition and evolution of transposable elements in this representative of the Old World monkey lineage, a group of diverse primates closely related to humans. The L1 family of long interspersed elements appears to have evolved as a single lineage, and Alu elements have evolved into four currently active lineages. We also found evidence of elevated horizontal transmissions of retroviruses and the absence of DNA transposon activity in the Old World monkey lineage. In addition, ∼100 precursors of composite SVA (short interspersed element, variable number of tandem repeat, and Alu) elements were identified, with the majority being shared by the common ancestor of humans and rhesus macaques. Mobile elements compose roughly 50% of primate genomes, and our findings illustrate their diversity and strong influence on genome evolution between closely related species

TE Hub: A community-oriented space for sharing and connecting tools, data, resources, and methods for transposable element annotation

Transposable elements (TEs) play powerful and varied evolutionary and functional roles, and are widespread in most eukaryotic genomes. Research into their unique biology has driven the creation of a large collection of databases, software, classification systems, and annotation guidelines. The diversity of available TE-related methods and resources raises compatibility concerns and can be overwhelming to researchers and communicators seeking straightforward guidance or materials. To address these challenges, we have initiated a new resource, TE Hub, that provides a space where members of the TE community can collaborate to document and create resources and methods. The space consists of (1) a website organized with an open wiki framework, https://tehub.org, (2) a conversation framework via a Twitter account and a Slack channel, and (3) bi-monthly Hub Update video chats on the platform’s development. In addition to serving as a centralized repository and communication platform, TE Hub lays the foundation for improved integration, standardization, and effectiveness of diverse tools and protocols. We invite the TE community, both novices and experts in TE identification and analysis, to join us in expanding our community-oriented resource

Contributions of Muscles and External Forces to Medial Knee Load Reduction Due to Osteoarthritis Braces

Background Braces for medial knee osteoarthritis can reduce medial joint loads through a combination of three mechanisms: application of an external brace abduction moment, alteration of gait dynamics, and reduced activation of antagonistic muscles. Although the effect of knee bracing has been reported independently for each of these parameters, no previous study has quantified their relative contributions to reducing medial knee loads. Methods In this study, we used a detailed musculoskeletal model to investigate immediate changes in medial and lateral loads caused by two different knee braces: OA Assist and OA Adjuster 3 (DJO Global). Seventeen osteoarthritis subjects and eighteen healthy controls performed overground gait trials in unbraced and braced conditions. Results Across all subjects, bracing reduced medial loads by 0.1 to 0.3 times bodyweight (BW), or roughly 10%, and increased lateral loads by 0.03 to 0.2 BW. Changes in gait kinematics due to bracing were subtle, and had little effect on medial and lateral joint loads. The knee adduction moment was unaltered unless the brace moment was included in its computation. Only one muscle, biceps femoris, showed a significant change in EMG with bracing, but this did not contribute to altered peak medial contact loads. Conclusions Knee braces reduced medial tibiofemoral loads primarily by applying a direct, and substantial, abduction moment to each subject's knee. To further enhance brace effectiveness, future brace designs should seek to enhance the magnitude of this unloader moment, and possibly exploit additional kinematic or neuromuscular gait modifications

Reductions in co-contraction following neuromuscular re-education in people with knee osteoarthritis

Background Both increased knee muscle co-contraction and alterations in central pain processing have been suggested to play a role in knee osteoarthritis pain. However, current interventions do not target either of these mechanisms. The Alexander Technique provides neuromuscular re-education and may also influence anticipation of pain. This study therefore sought to investigate the potential clinical effectiveness of the AT intervention in the management of knee osteoarthritis and also to identify a possible mechanism of action. Methods A cohort of 21 participants with confirmed knee osteoarthritis were given 20 lessons of instruction in the Alexander Technique. In addition to clinical outcomes EMG data, quantifying knee muscle co-contraction and EEG data, characterising brain activity during anticipation of pain, were collected. All data were compared between baseline and post-intervention time points with a further 15-month clinical follow up. In addition, biomechanical data were collected from a healthy control group and compared with the data from the osteoarthritis subjects. Results: Following AT instruction the mean WOMAC pain score reduced by 56% from 9.6 to 4.2 (P<0.01) and this reduction was maintained at 15 month follow up. There was a clear decrease in medial co-contraction at the end of the intervention, towards the levels observed in the healthy control group, both during a pre-contact phase of gait (p<0.05) and during early stance (p<0.01). However, no changes in pain-anticipatory brain activity were observed. Interestingly, decreases in WOMAC pain were associated with reductions in medial co-contraction during the pre-contact phase of gait. Conclusions: This is the first study to investigate the potential effectiveness of an intervention aimed at increasing awareness of muscle behaviour in the clinical management of knee osteoarthritis. These data suggest a complex relationship between muscle contraction, joint loading and pain and support the idea that excessive muscle co-contraction may be a maladaptive response in this patient group. Furthermore, these data provide evidence that, if the activation of certain muscles can be reduced during gait, this may lead to positive long-term clinical outcomes. This finding challenges clinical management models of knee osteoarthritis which focus primarily on muscle strengthening