Utilization of the Rat Tibial Nerve Transection Model to Evaluate Cellular and Molecular Mechanisms Underpinning Denervation-Mediated Muscle Injury.

Peripheral nerve injury denervates muscle, resulting in muscle paralysis and atrophy. This is reversible if timely muscle reinnervation occurs. With delayed reinnervation, the muscle's reparative ability declines, and muscle-resident fibro-adipogenic progenitor cells (FAPs) proliferate and differentiate, inducing fibro-fatty muscle degradation and thereby physical disability. The mechanisms by which the peripheral nerve regulates FAPs expansion and differentiation are incompletely understood. Using the rat tibial neve transection model, we demonstrated an increased FAPs content and a changing FAPs phenotype, with an increased capacity for adipocyte and fibroblast differentiation, in gastrocnemius muscle post-denervation. The FAPs response was inhibited by immediate tibial nerve repair with muscle reinnervation via neuromuscular junctions (NMJs) and sensory organs (e.g., muscle spindles) or the sensory protection of muscle (where a pure sensory nerve is sutured to the distal tibial nerve stump) with reinnervation by muscle spindles alone. We found that both procedures reduced denervation-mediated increases in glial-cell-line-derived neurotrophic factor (GDNF) in muscle and that GDNF promoted FAPs adipogenic and fibrogenic differentiation in vitro. These results suggest that the peripheral nerve controls FAPs recruitment and differentiation via the modulation of muscle GDNF expression through NMJs and muscle spindles. GDNF can serve as a therapeutic target in the management of denervation-induced muscle injury.

Breast cancer outcomes based on method of detection in community-based breast cancer registry.

PURPOSE: The impact of opportunistic screening mammography in the United States is difficult to quantify, partially due to lack of inclusion regarding method of detection (MOD) in national registries. This study sought to determine the feasibility of MOD collection in a multicenter community registry and to compare outcomes and characteristics of breast cancer based on MOD. METHODS: We conducted a retrospective study of breast cancer patients from a multicenter tumor registry in Missouri from January 2004 - December 2018. Registry data were extracted by certified tumor registrars and included MOD, clinicopathologic information, and treatment. MOD was assigned as screen-detected or clinically detected. Data were analyzed at the patient level. Chi-squared tests were used for categorical variable comparison and Mann-Whitney-U test was used for numerical variable comparison. RESULTS: 5351 women (median age, 63 years; interquartile range, 53-73 years) were included. Screen-detected cancers were smaller than clinically detected cancers (median size 12 mm vs. 25 mm; P < .001) and more likely node-negative (81% vs. 54%; P < .001), lower grade (P < .001), and lower stage (P < .001). Screen-detected cancers were more likely treated with lumpectomy vs. mastectomy (73% vs. 41%; P < .001) and less likely to require chemotherapy (24% vs. 52%; P < .001). Overall survival for patients with invasive breast cancer was higher for screen-detected cancers (89% vs. 74%, P < .0001). CONCLUSION: MOD can be routinely collected and linked to breast cancer outcomes through tumor registries, with demonstration of significant differences in outcome and characteristics of breast cancers based on MOD. Routine inclusion of MOD in US tumor registries would help quantify the impact of opportunistic screening mammography in the US.

Identification, Isolation, and Characterization of Fibro-Adipogenic Progenitors (FAPs) and Myogenic Progenitors (MPs) in Skeletal Muscle in the Rat.

Fibro-adipogenic Progenitors (FAPs) are resident interstitial cells in skeletal muscle that, together with myogenic progenitors (MPs), play a key role in muscle homeostasis, injury, and repair. Current protocols for FAPs identification and isolation use flow cytometry/fluorescence-activated cell sorting (FACS) and studies evaluating their function in vivo to date have been undertaken exclusively in mice. The larger inherent size of the rat allows for a more comprehensive analysis of FAPs in skeletal muscle injury models, especially in severely atrophic muscle or when investigators require substantial tissue mass to conduct multiple downstream assays. The rat additionally provides a larger selection of muscle functional assays that do not require animal sedation or sacrifice, thus minimizing morbidity and animal use by enabling serial assessments. The flow cytometry/FACS protocols optimized for mice are species specific, notably restricted by the characteristics of commercially available antibodies. They have not been optimized for separating FAPs from rat or highly fibrotic muscle. A flow cytometry/FACS protocol for the identification and isolation of FAPs and MPs from both healthy and denervated rat skeletal muscle was developed, relying on the differential expression of surface markers CD31, CD45, Sca-1, and VCAM-1. As rat-specific, flow cytometry-validated primary antibodies are severely limited, in-house conjugation of the antibody targeting Sca-1 was performed. Using this protocol, successful Sca-1 conjugation was confirmed, and flow cytometric identification of FAPs and MPs was validated by cell culture and immunostaining of FACS-isolated FAPs and MPs. Finally, we report a novel FAPs time-course in a prolonged (14 week) rat denervation model. This method provides the investigators the ability to study FAPs in a novel animal model.

Inadequate assessment of adherence to maintenance medication leads to loss of power and increased costs in trials of severe asthma therapy: results from a systematic literature review and modelling study.

Adherence to inhaled maintenance therapy in severe asthma is rarely adequately assessed, and its influence on trial outcomes is unknown. We systematically determined how adherence to maintenance therapy is assessed in clinical trials of "add-on" therapy for severe asthma. We model the improvement in trial power that could be achieved by accurately assessing adherence.A systematic search of six major databases identified randomised trials of add-on therapy for severe asthma. The relationship between measuring adherence and study outcomes was assessed. An estimate of potential improvements in statistical power and sample size was derived using digitally recorded adherence trial data.87 randomised controlled trials enrolling 22 173 participants were included. Adherence assessment was not reported in 67 trials (n=13 931, 63%). Studies that reported adherence used a range of self-report and subjective methods. None of the studies employed an objective assessment of adherence. Studies that reported adherence had a significantly reduced pooled variance in forced expiratory volume in 1 s (FEV1) compared to those that did not assess adherence: s2=0.144 L2 versus s2=0.168 L2, p<0.0001. Power to detect clinically relevant changes in FEV1 was significantly higher in trials that reported adherence assessment (mean power achieved 59% versus 49%). Modelling suggests that up to 50% of variance in FEV1 outcomes is attributable to undetected variations in adherence. Controlling for such variations could potentially halve the required sample size.Few trials of add-on therapy monitor adherence to maintenance inhaled therapy, resulting in a greater variance in trial outcomes and inadequate power for determining efficacy.

Case 227: Endobronchial Carcinoid Tumor with Incidental Metastatic Breast Cancer Detected with Somatostatin Receptor Scintigraphy ((111)In Pentreotide).

HISTORY: A 30-year-old woman with polycystic ovarian syndrome who was undergoing hormone replacement therapy presented with a 6-month history of a nonproductive cough and a 1-day history of hemoptysis (approximately 20 mL). Intravenous contrast material-enhanced (100 mL of Omnipaque 350; GE Healthcare, Princeton, NJ) computed tomographic (CT) pulmonary angiography was performed to evaluate for pulmonary embolism. On the basis of the CT pulmonary angiographic findings, chromogranin A and 5-hydroxyindoleacetic acid levels were measured and were 7 nmol/L (343 µg/L) (high) and 2.9 mg per 24 hours (15.167 µmol/d) (normal), respectively. This patient underwent bronchoscopy and biopsy. After these tests, she was referred for whole-body scintigraphy, which revealed an unexpected finding that was further investigated with fluorine 18 ((18)F) flurodeoxyglucose (FDG) positron emission tomography (PET) and CT.

Comparison of 1 and 2 days per week of strength training in children.

The purpose of this study was to compare the effects of 1 and 2 days per week of strength training on upper body strength, lower body strength, and motor performance ability in children. Twenty-one girls and 34 boys between the ages of 7.1 and 12.3 years volunteered to participate in this study. Participants strength trained either once per week (n = 22) or twice per week (n = 20) for 8 weeks at a community-based youth fitness center. Each training session consisted of a single set of 10-15 repetitions on 12 exercises using child-size weight machines. Thirteen children who did not strength train served as age-matched controls. One repetition maximum (1RM) strength on the chest press and leg press, handgrip strength, long jump, vertical jump, and flexibility were assessed at baseline and posttraining. Only participants who strength trained twice per week made significantly greater gains in 1RM chest press strength, compared to the control group (11.5 and 4.4% respectively, p < .05). Participants who trained once and twice per week made gains in 1RM leg press strength (14.2 and 24.7%, respectively) that were significantly greater than control group gains (2.4%). On average, participants who strength trained once per week achieved 67% of the 1RM strength gains. No significant differences between groups were observed on other outcome measures. These findings support the concept that muscular strength can be improved during the childhood years and favor a training frequency of twice per week for children participating in an introductory strength training program.