Identification and Characterization of AES-135, a Hydroxamic Acid-Based HDAC Inhibitor That Prolongs Survival in an Orthotopic Mouse Model of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive, incurable cancer with a 20% 1 year survival rate. While standard-of-care therapy can prolong life in a small fraction of cases, PDAC is inherently resistant to current treatments, and novel therapies are urgently required. Histone deacetylase (HDAC) inhibitors are effective in killing pancreatic cancer cells in in vitro PDAC studies, and although there are a few clinical studies investigating combination therapy including HDAC inhibitors, no HDAC drug or combination therapy with an HDAC drug has been approved for the treatment of PDAC. We developed an inhibitor of HDACs, AES-135, that exhibits nanomolar inhibitory activity against HDAC3, HDAC6, and HDAC11 in biochemical assays. In a three-dimensional coculture model, AES-135 kills low-passage patient-derived tumor spheroids selectively over surrounding cancer-associated fibroblasts and has excellent pharmacokinetic properties in vivo. In an orthotopic murine model of pancreatic cancer, AES-135 prolongs survival significantly, therefore representing a candidate for further preclinical testing

Nonrandom Distribution of Interhomolog Recombination Events Induced by Breakage of a Dicentric Chromosome in Saccharomyces cerevisiae

Dicentric chromosomes undergo breakage in mitosis, resulting in chromosome deletions, duplications, and translocations. In this study, we map chromosome break sites of dicentrics in Saccharomyces cerevisiae by a mitotic recombination assay. The assay uses a diploid strain in which one homolog has a conditional centromere in addition to a wild-type centromere, and the other homolog has only the wild-type centromere; the conditional centromere is inactive when cells are grown in galactose and is activated when the cells are switched to glucose. In addition, the two homologs are distinguishable by multiple single-nucleotide polymorphisms (SNPs). Under conditions in which the conditional centromere is activated, the functionally dicentric chromosome undergoes double-stranded DNA breaks (DSBs) that can be repaired by mitotic recombination with the homolog. Such recombination events often lead to loss of heterozygosity (LOH) of SNPs that are centromere distal to the crossover. Using a PCR-based assay, we determined the position of LOH in multiple independent recombination events to a resolution of ∼4 kb. This analysis shows that dicentric chromosomes have recombination breakpoints that are broadly distributed between the two centromeres, although there is a clustering of breakpoints within 10 kb of the conditional centromere

Escherichia coli Frameshift Mutation Rate Depends on the Chromosomal Context but Not on the GATC Content Near the Mutation Site

Different studies have suggested that mutation rate varies at different positions in the genome. In this work we analyzed if the chromosomal context and/or the presence of GATC sites can affect the frameshift mutation rate in the Escherichia coli genome. We show that in a mismatch repair deficient background, a condition where the mutation rate reflects the fidelity of the DNA polymerization process, the frameshift mutation rate could vary up to four times among different chromosomal contexts. Furthermore, the mismatch repair efficiency could vary up to eight times when compared at different chromosomal locations, indicating that detection and/or repair of frameshift events also depends on the chromosomal context. Also, GATC sequences have been proved to be essential for the correct functioning of the E. coli mismatch repair system. Using bacteriophage heteroduplexes molecules it has been shown that GATC influence the mismatch repair efficiency in a distance- and number-dependent manner, being almost nonfunctional when GATC sequences are located at 1 kb or more from the mutation site. Interestingly, we found that in E. coli genomic DNA the mismatch repair system can efficiently function even if the nearest GATC sequence is located more than 2 kb away from the mutation site. The results presented in this work show that even though frameshift mutations can be efficiently generated and/or repaired anywhere in the genome, these processes can be modulated by the chromosomal context that surrounds the mutation site

Return-to-Play Rates and Clinical Outcomes of Baseball Players After Concomitant Ulnar Collateral Ligament Reconstruction and Selective Ulnar Nerve Transposition.

Background: Injury to the ulnar collateral ligament (UCL) leading to medial elbow instability and possible ulnar neuritis is common in overhead-throwing athletes. Treatment may require UCL reconstruction (UCLR) and concomitant ulnar nerve transposition (UNT) for those with preoperative ulnar neuritis. Purpose: To evaluate the return-to-play (RTP) rates, clinical outcomes, and rates of persistent ulnar neuritis after concomitant UCLR and UNT in a cohort of baseball players with confirmed preoperative ulnar neuritis. Study Design: Case series; Level of evidence, 4. Methods: Eligible patients were those who underwent concomitant UCLR and UNT at a single institution between January 2008 and June 2018 and who had a minimum of 2 years of follow-up. Additional inclusion criteria were athletes who identified as baseball players and who had a confirmed history of ulnar neuritis. Patients were contacted at a minimum of 2 years from surgery and assessed with the Kerlan-Jobe Orthopaedic Clinic (KJOC) Shoulder and Elbow Score, Andrew-Timmerman (A-T) Elbow Score, Mayo Elbow Performance Score (MEPS), Single Assessment Numeric Evaluation (SANE) score, and a custom RTP questionnaire. Results: Included were 22 male baseball players with a mean age of 18.9 ± 2.1 years (range, 16-25 years). The mean follow-up was 6.1 ± 2.4 years (range, 2.5-11.7 years). Preoperatively, all 22 patients reported ulnar nerve sensory symptoms, while 4 (18.2%) patients reported ulnar nerve motor symptoms. At the final follow-up, 7 (31.8%) patients reported persistent ulnar nerve sensory symptoms, while none of the patients reported persistent ulnar nerve motor symptoms. Overall, 16 (72.7%) players were able to return to competitive play at an average of 11.2 months. The mean postoperative patient-reported outcome scores for the KJOC Shoulder and Elbow Score, MEPS, A-T Elbow Score, and SANE score were 77.9 ± 20.9 (range, 14-100), 92.7 ± 12.7 (range, 45-100), 86.1 ± 17.1 (range, 30-100), and 85.5 ± 14.8 (range, 50-100), respectively. Conclusion: This study demonstrated that after concomitant UCLR and UNT for UCL insufficiency and associated ulnar neuritis, baseball players can expect reasonably high RTP rates and subjective outcomes; however, rates of persistent sensory ulnar neuritis can be as high as 30%

Return to Play Criteria Following Operative Management of Acromioclavicular Joint Separation: A Systematic Review

Introduction: Acromioclavicular (AC) joint separation is a leading cause of shoulder injury among athletes. High grade injuries may require operative fixation, and comprehensive return to play guidelines have not yet been established. The purpose of this investigation is to summarize return to play criteria following operative management of AC joint separation. Methods: A systematic review of the literature was performed to evaluate clinical evidence regarding return to play following operative management of isolated AC joint separation. Studies satisfying inclusion criteria were analyzed for return to play timeline and other factors used to guide return to play following surgery. Results: Sixty-three studies with at least 1 explicitly stated return to play criterion were identified out of an initial database search of 1,253 published articles. Eight separate categories of return to play criteria were identified, the most common of which was time from surgery (95.2%). Return to play timelines ranged from 2 – 12 months, the most common timeline being 6 months (37.8%). Only 4 (6.3%) studies utilized conditional criteria to guide return to play, among which included range of motion, strength, clinical stability, radiographic stability, functional assessment, safety assessment, and hardware removal. Discussion: Most published studies utilize only time-based return to play criteria, and only a small number of studies employ patient-centered conditional criteria. While this systematic review helps provide a foundation for developing a comprehensive return to play checklist, further investigation is needed to establish safe and effective guidelines that will enable athletes to safely return to sport and minimize the recurrence of injury

Quality Control of Motor Unit Number Index (MUNIX) Measurements in 6 Muscles in a Single-Subject “Round-Robin” Setup

Background Motor Unit Number Index (MUNIX) is a neurophysiological measure that provides an index of the number of lower motor neurons in a muscle. Its performance across centres in healthy subjects and patients with Amyotrophic Lateral Sclerosis (ALS) has been established, but inter-rater variability between multiple raters in one single subject has not been investigated. Objective To assess reliability in a set of 6 muscles in a single subject among 12 examiners (6 experienced with MUNIX, 6 less experienced) and to determine variables associated with variability of measurements. Methods Twelve raters applied MUNIX in six different muscles (abductor pollicis brevis (APB), abductor digiti minimi (ADM), biceps brachii (BB), tibialis anterior (TA), extensor dig. brevis (EDB), abductor hallucis (AH)) twice in one single volunteer on consecutive days. All raters visited at least one training course prior to measurements. Intra- and inter-rater variability as determined by the coefficient of variation (COV) between different raters and their levels of experience with MUNIX were compared. Results Mean intra-rater COV of MUNIX was 14.0% (±6.4) ranging from 5.8 (APB) to 30.3% (EDB). Mean inter-rater COV was 18.1 (±5.4) ranging from 8.0 (BB) to 31.7 (AH). No significant differences of variability between experienced and less experienced raters were detected. Conclusion We provide evidence that quality control for neurophysiological methods can be performed with similar standards as in laboratory medicine. Intra- and inter-rater variability of MUNIX is muscle-dependent and mainly below 20%. Experienced neurophysiologists can easily adopt MUNIX and adequate teaching ensures reliable utilization of this method