Examining the Accuracy of the Polar A360 Monitor.

ABSTRACT: Rider, BC, Conger, SA, Ditzenberger, GL, Besteman, SS, Bouret, CM, and Coughlin, AM. Examining the accuracy of the Polar A360 monitor. J Strength Cond Res 35(8): 2165-2169, 2021-The purpose of this study was to determine the accuracy of the Polar A360 heart rate (HR) monitor during periods of rest, walking/running, and active/passive recovery from exercise. Thirty collegiate athletes (women n = 15 and men n = 15) wore an A360 monitor and a previously validated chest HR monitor (Polar RS400) that served as the criterion measurement across a range of resting and walking/running intensities. First, subjects rested in a supine, seated, and standing position. Next, each subject walked on a treadmill at 1.6 kilometers per hour (kph). Speed was increased by 1.6 kph every 2 minutes until volitional fatigue. Then, subjects walked at 4.8 kph followed by a seated recovery stage. Heart rate was recorded in 30-second increments. Total mean difference in HR readings, percent accuracy, and intraclass correlation coefficient (ICC) analysis established the level of agreement between devices. Bland-Altman plots and a regression were used to examine the agreement between devices. The A360 demonstrated a strong correlation with the RS400 (r2 = 0.98) across time points. The analysis of variance with repeated measures indicated an overall significant difference (p < 0.001) between devices. The A360 significantly underestimated HR during the 6.4-kph speed only (p < 0.05) (effect size 0.26). The greatest percent accuracy occurred during rest (91%) and recovery (90%). An ICC of 0.98 (SEM: 0.35) demonstrates a strong level of agreement between devices. The A360 is accurate at rest and during various walking and running speeds and thus is a device that can be used with confidence by athletes for specific training purposes. Future research should examine accuracy during weight training and other sport-specific activities.

Time-based Assessment of Hearing Preservation Rates After Microsurgical Resection of Vestibular Schwannomas: A Systematic Review.

OBJECTIVE: To determine short- and intermediate-term hearing preservation rates after microsurgical resection of vestibular schwannoma (VS). DATA SOURCES: Systematic review of the Ovid, Cochrane, EMBASE, and Web of Science databases. STUDY SELECTION: This study was restricted to full-text English-language articles detailing VS resection via the middle cranial fossa or retrosigmoid approaches. Documentation of pre- and posttreatment hearing outcomes with American Academy of Otolaryngology-Head and Neck Surgery, Gardner-Robertson, or word recognition score scales, as well as time to follow-up were required. Duplicate data sets, studies with >10% of patients with neurofibromatosis two, previous or nonsurgical VS treatment, case reports with

The Influence of Tissue Plasminogen Activator I/D Polymorphism on the tPA Response to Exercise.

The purpose was to determine if the Alu-insertion (I)/deletion (D) polymorphism of the tissue plasminogen activator (tPA) gene influences the tPA response to maximal exercise. Fifty male subjects (age = 23.6 ± 4.7 yrs) completed a maximal treadmill exercise test. Blood samples were drawn before and immediately after exercise for determination of plasma tPA antigen and activity. Isolated DNA was amplified via polymerase chain reaction, electrophoresed, and visually amplified to determine tPA genotype. Subjects were classified as possessing the D allele (D) (n = 28) or being homozygous for the I allele (I) (n = 22). Differences in tPA antigen and activity were assessed using a two-factor (genotype and time) repeated measures analysis of variance. There were significant main effects for time for tPA antigen and activity (p < 0.05), but no main effect for genotype. Furthermore, there was no genotype x time interaction due to a similar increase in tPA antigen in the D group (pre-exercise = 5.83 + 2.39 ng/ml, post-exercise = 21.88 + 7.38 ng/ml) and the I group (pre-exercise = 5.61 + 2.82 ng/ml, post-exercise = 19.05 + 7.67 ng/ml) and a similar increase in tPA activity in the D group (pre-exercise = 0.39 ± 0.19 IU/ml, post-exercise = 9.73 ± 4.22 IU/ml) and I group (pre-exercise = 0.45 ± 0.29 IU/ml, post-exercise = 9.76 ± 5.50 IU/ml). The I/D polymorphism of the tPA gene does not influence the tPA antigen nor tPA activity responses to maximal exercise in healthy, young, sedentary males.

Systematic Review of Hearing Preservation After Radiotherapy for Vestibular Schwannoma.

OBJECTIVE: To determine the long-term hearing preservation rate for spontaneous vestibular schwannoma treated by primary radiotherapy. DATA SOURCES: The MEDLINE/PubMed, Web of Science, Cochrane Reviews, and EMBASE databases were searched using a comprehensive Boolean keyword search developed in conjunction with a scientific librarian. English language papers published from 2000 to 2016 were evaluated. STUDY SELECTION: Inclusion criteria: full articles, pretreatment and posttreatment audiograms or audiogram based scoring system, vestibular schwannoma only tumor type, reported time to follow-up, published after 1999, use of either Gamma Knife or linear accelerator radiotherapy. EXCLUSION CRITERIA: case report or series with fewer than five cases, inadequate audiometric data, inadequate time to follow-up, neurofibromatosis type 2 exceeding 10% of study population, previous treatment exceeding 10% of study population, repeat datasets, use of proton beam therapy, and non-English language. DATA EXTRACTION: Two reviewers independently analyzed papers for inclusion. Class A/B, 1/2 hearing was defined as either pure tone average less than or equal to 50 db with speech discrimination score more than or equal to 50%, American Academy of Otolaryngology-Head & Neck Surgery (AAO-HNS) Hearing Class A or B, or Gardner-Robertson Grade I or II. Aggregate data were used when individual data were not specified. DATA SYNTHESIS: Means were compared with student t test. CONCLUSIONS: Forty seven articles containing a total of 2,195 patients with preserved Class A/B, 1/2 hearing were identified for analysis. The aggregate crude hearing preservation rate was 58% at an average reporting time of 46.6 months after radiotherapy treatment. Analysis of time-based reporting shows a clear trend of decreased hearing preservation extending to 10-year follow-up. This data encourages a future long-term controlled trial.

Serial office-based steroid injections for treatment of idiopathic subglottic stenosis.

OBJECTIVES/HYPOTHESIS: Current treatment options for idiopathic subglottic stenosis include endoscopic interventions, resection, and tracheotomy. Recently, serial office-based steroid injections were proposed as an alternative that may stabilize or induce regression of airway stenosis without the need for repeated operations. Procedure completion rate, pain, complications, effect on stenosis, time since the last operation, and limitations have not been described. STUDY DESIGN: Retrospective case series. METHODS: Retrospective series of 19 patients undergoing serial office-based steroid injection for idiopathic subglottic stenosis. Outcome measures included completion rate, procedure-related pain scores, complications, percentage of airway stenosis, and time since the last operative intervention. RESULTS: Procedure completion rate was 98.8%. Average pain score during the procedure was 2.3 ± 1.7 on a 10-point scale. There were no immediate complications. One patient underwent awake tracheotomy 8 days after her second injection and was later decannulated. Average stenosis decreased from 35% ± 15% to 25% ± 15% (n = 16; P = .086) over the first of three injections and 40% ± 15% to 25% ± 10% to 20% ± 10% (n = 8; P = .002) for those patients completing two sets of three injections. Fourteen of 17 patients undergoing at least three injections have not returned to the operating room since the first injection. CONCLUSIONS: Office-based steroid injection represents a promising new treatment pathway for a disease that requires long-term management, offering a purely pharmacologic approach to a disorder that has traditionally been approached from a mechanical perspective. It is safe, well tolerated, and effective. Furthermore, it may help patients and physicians avoid repeated trips to the operating room and the associated risks. LEVEL OF EVIDENCE: 4. Laryngoscope, 127:2475-2481, 2017.

Bone-anchored hearing aid and skin graft removal with subsequent cochlear implantation.

We describe a novel technique of scalp flap rearrangement for cochlear implant (CI) candidates who have previously undergone ipsilateral bone-anchored hearing aid (BAHA) placement. One patient with single-sided deafness (SSD) underwent removal of a BAHA with subsequent scalp rearrangement for coverage of the implant site. After adequate healing of the scalp rotational flap, he underwent uncomplicated cochlear implantation without soft tissue complications. With increasing utilization of CIs in SSD, there will be more patients undergoing cochlear implantation who have previously had a BAHA. We present a novel method for accomplishing this goal while minimizing the risk of soft tissue complications. Laryngoscope, 126:2601-2604, 2016.

Age and aerobic training status effects on plasma and skeletal muscle tPA and PAI-1.

INTRODUCTION: Reductions in fibrinolytic potential occur with both aging and physical inactivity and are associated with an increased cardiovascular disease risk. Plasmin, the enzyme responsible for the enzymatic degradation of fibrin clots, is activated by tissue plasminogen activator (tPA), while plasminogen activator inhibitor-1 (PAI-1) inhibits its activation. Currently, fibrinolysis research focuses almost exclusively on changes within the plasma. However, tPA and PAI-1 are expressed by human skeletal muscle (SM). Currently, no studies have focused on changes in SM fibrinolytic activity with regard to aging and aerobic fitness. PURPOSE: The purpose of this study was to cross-sectionally evaluate effects of age and aerobic fitness on tPA and PAI-1 expressions and activity in SM. METHODS: Twenty-six male subjects were categorized into the following groups: (1) young aerobically trained (n = 8); (2) older aerobically trained (n = 6); (3) young aerobically untrained (n = 7); and (4) older aerobically untrained (n = 5). Muscle biopsies were obtained from each subject. SM tPA activity was assessed using gel zymography and SM tPA and PAI-1 expressions were assessed using RT-PCR. RESULTS: Trained subjects had higher SM tPA activity compared to untrained (25.3 ± 2.4 × 10(3) vs. 21.5 ± 5.6 × 10(3) pixels, respectively; p = 0.03) with no effect observed for age. VO2 max and SM tPA activity were also significantly correlated (r = 0.42; p < 0.04). SM tPA expression was higher in older participants, but no effect of fitness level was observed. No differences were observed for PAI-1 expression in SM. CONCLUSIONS: Higher levels of aerobic fitness are associated with increased fibrinolytic activity in SM.

Effect of compression stockings on physiological responses and running performance in division III collegiate cross-country runners during a maximal treadmill test.

There is a growing trend for runners to use compression stockings (CS) to improve performance. The purpose of this study was to determine the effect of CS on physiological variables associated with running performance. Participants were 10 NCAA division III cross-country runners. The study used a randomized, crossover design with 2 conditions (with CS and without CS). Both conditions consisted of a maximal treadmill test that involved 3-minute stages of increasing speed and incline, separated by a minute and one-half walking recovery stage. Seven days later, the participants repeated the maximal test but switched CS condition. Heart rate, blood lactate (BLa), blood lactate threshold, maximal oxygen consumption (VO2max), respiratory exchange ratio, rating of perceived exertion, and time to fatigue were measured. Before and during the maximal treadmill tests, the variables showed no significant difference (p ≤ 0.05) between the CS conditions. Blood lactate was lower while wearing CS when measured during recovery at the 1-minute (CS = 13.3 ± 2.9 mmol · L(-1), non-CS = 14.8 ± 2.8 mmol · L(-1), p = 0.03) and the 5-minute (CS = 11.0 ± 2.7 mmol · L(-1), non-CS = 12.8 ± 2.8 mmol · L(-1), p = 0.02) periods. Time to fatigue was longer without CS (CS = 23.570 ± 2.39 minutes, non-CS = 23.93 ± 2.49 minutes, p = 0.04). These findings suggest that CS may not improve running performance, but could lend credence to certain manufacturers' claims of improved recovery through lower BLa values after exercise.

Paracrine potential of fibroblasts exposed to cigarette smoke extract with vascular growth factor induction.

OBJECTIVES/HYPOTHESIS: Nicotine, a major constituent of cigarette smoke, can activate the cholinergic anti-inflammatory pathway by binding to α7-nicotinic acetylcholine receptor (α7nAChR) expressed on the surface of certain cells. Here, we ask whether cigarette smoke extract induced different paracrine factors compared to the in vivo regulator of inflammation, tumor necrosis factor-α, in human vocal fold fibroblasts (hVFFs) shown to express low levels of α7nAChR. STUDY DESIGN: In vitro. METHODS: α7nAChR was detected by nested polymerase chain reaction and immunohistochemistry. γH2AX, a marker for DNA double-stand breaks, was measured by immunofluorescence. Cigarette smoke extract was prepared in accordance with investigators studying effects of cigarette smoke. hVFFs treated for 3 hours had media replaced for an additional 24 hours. Cytokine, chemokine, and growth factor levels in media were assessed by multiplex analysis. RESULTS: α7nAChR expression levels decreased with the passage number of fibroblasts. Tumor necrosis factor-α induced a significantly different profile of cytokines, chemokines, and growth factor compared to cigarette smoke extract exposure. Cigarette smoke extract at a concentration not associated with induction of γH2AX nuclear foci significantly increased vascular endothelial growth factor. CONCLUSIONS: Cigarette smoke extract elicited a response important for regulation of angiogenesis and vascular permeability during inflammation, without evidence of DNA double-stand breaks associated with carcinogenesis. hVFFs are capable of participating in paracrine regulation of pathological blood vessel formation associated with cigarette smoking-related diseases (ie, Reinke edema). These cells express α7nAChR, an essential component of the cholinergic anti-inflammatory pathway regulated by the vagus nerve in certain tissues and a target of therapeutic agents.

Cone degeneration following rod ablation in a reversible model of retinal degeneration.

PURPOSE: Amphibian retinas regenerate after injury, making them ideal for studying the mechanisms of retinal regeneration, but this leaves their value as models of retinal degeneration in question. The authors asked whether the initial cellular changes after rod loss in the regenerative model Xenopus laevis mimic those observed in nonregenerative models. They also asked whether rod loss was reversible. METHODS: The authors generated transgenic X. laevis expressing the Escherichia coli enzyme nitroreductase (NTR) under the control of the rod-specific rhodopsin (XOP) promoter. NTR converts the antibiotic metronidazole (Mtz) into an interstrand DNA cross-linker. A visually mediated behavioral assay and immunohistochemistry were used to determine the effects of Mtz on the vision and retinas of XOPNTR F1 tadpoles. RESULTS: NTR expression was detected only in the rods of XOPNTR tadpoles. Mtz treatment resulted in rapid vision loss and near complete ablation of rod photoreceptors by day 12. Müller glial cell hypertrophy and progressive cone degeneration followed rod cell ablation. When animals were allowed to recover, new rods were born and formed outer segments. CONCLUSIONS: The initial secondary cellular changes detected in the rodless tadpole retina mimic those observed in other models of retinal degeneration. The rapid and synchronous rod loss in XOPNTR animals suggested this model may prove useful in the study of retinal degeneration. Moreover, the regenerative capacity of the Xenopus retina makes these animals a valuable tool for identifying the cellular and molecular mechanisms at work in lower vertebrates with the remarkable capacity of retinal regeneration.

Discordant hemodynamic and fibrinolytic adaptations following a 6-week cardiac rehabilitation program.

The present study evaluated changes in hemodynamics and fibrinolysis during 6 weeks of participation in an exercise-based cardiac rehabilitation program. Fourteen patients trained for 3 days per week for 6 weeks using American College of Sports Medicine guidelines for intensity and duration. Blood samples were taken at baseline and after 3 and 6 weeks of participation and analyzed for tissue plasminogen activator (t-PA) activity and antigen, plasminogen activator inhibitor-1 (PAI-1) activity and antigen, and relative quantification of t-PA and PAI-1 RNA. Data were analyzed using repeated measures analysis of variance. Training elicited significant decreases in submaximal exercise heart rate and systolic blood pressure and resting systolic blood pressure (p<.05). There were no significant changes in plasma concentrations of t-PA or PAI-1, and no change was observed in t-PA or PAI-1 gene expression. The present findings suggest that favorable hemodynamic adaptations may occur after only 6 weeks of exercise-based cardiac rehabilitation, but longer training periods may be needed to elicit positive hemostatic adaptations.

Temporal changes in tPA and PAI-1 after maximal exercise.

PURPOSE: Although fibrinolysis increases with acute exercise, it decreases rapidly during the postexercise period. Therefore, the time point at which blood samples are collected postexercise could affect reported tissue plasminogen activator (t-PA) and/or plasminogen activator inhibitor-1 (PAI-1) levels. The purpose of this study was to determine the time course of t-PA and PAI-1 changes after acute maximal exercise. METHODS: Eight healthy males performed a graded maximal exercise test on a treadmill. Venous blood samples were collected using an indwelling catheter before exercise and at 1, 2, 4, 6, 8, and 10 min postexercise. Mean differences in t-PA activity, t-PA antigen, and PAI-1 activity at each time point were assessed using a repeated measures ANOVA. Post hoc means comparisons were performed by contrasting the 1-min postexercise value against all other time points. RESULTS: Both t-PA activity and t-PA antigen significantly increased from pre- to postexercise (P < 0.05). t-PA activity did not change from 1 to 2 min postexercise but decreased significantly at 4 min postexercise. Likewise, t-PA antigen remained elevated from 1 to 2 min postexercise but decreased at 4 min postexercise. PAI-1 decreased from pre- to postexercise but did not change during the 10-min postexercise period. CONCLUSION: To accurately evaluate the t-PA response to acute exercise, blood samples should be collected within 2 min after the cessation of exercise.

Coagulation and fibrinolytic responses to manual versus automated snow removal.

PURPOSE: The purpose of this study was to assess coagulation and fibrinolytic responses to snow removal. METHODS: Thirteen healthy male subjects (age = 26 +/- 5 yr, height = 179.0 +/- 7.0 cm, weight = 78.7 +/- 16.1 kg, .VO2max = 54.7 +/- 8.9 mL.kg-1.min-1) underwent maximal treadmill stress testing (TM), 10 min of snow shoveling (SS), and 10 min of snow removal using an automated snow thrower (ST). Blood was collected immediately before and after each test and analyzed for von Willebrand Factor antigen (vWF:ag), tissue plasminogen activator (tPA) antigen, and plasminogen activator inhibitor-1 (PAI-1) activity. Data were analyzed using a two-factor repeated-measures analysis of variance. RESULTS: vWF:ag significantly increased during TM (84.7 +/- 21.7% normal preexercise, 149.0 +/- 45.6% normal postexercise) but not SS or ST. TM resulted in significant increases in tPA antigen (6.54 +/- 2.76 ng.mL-1 preexercise, 21.39 +/- 10.56 ng.mL-1 postexercise) and both SS and TM caused significant reductions in PAI-1 activity (SS = 15.1 +/- 3.8 AU.mL-1 preexercise, 13.2 +/- 4.3 AU.mL-1 postexercise; TM = 15.3 +/- 3.6 AU.mL-1 preexercise, 10.5 +/- 5.3 AU.mL-1 postexercise). Postexercise PAI-1 activity was significantly lower for TM versus SS. tPA antigen was unchanged after SS and ST, and PAI-1 activity was unchanged after ST. CONCLUSION: vWF:ag is unchanged after self-paced snow shoveling and automated snow removal in young, healthy males. Snow shoveling acutely increases fibrinolytic potential in this population, although not to the degree observed after maximal treadmill exercise.

Exercise-induced changes in coagulation and fibrinolysis in healthy populations and patients with cardiovascular disease.

This review highlights the clinical significance of coagulation and fibrinolytic responses, and adaptations in healthy individuals and patients with cardiovascular disease (CVD). Much of the review focuses on indicators of the potential for coagulation and fibrinolysis. The terms 'coagulation potential' and 'fibrinolytic potential' are used frequently, as much of the literature in the area of exercise haemostasis evaluates factors that reflect an increased potential for coagulation, while coagulation per se, may or may not be occurring. Similarly, fibrinolysis is definitively the lysis of inappropriate or excessive blood clot, which may or may not be occurring when the enzymes that stimulate fibrinolysis are activated. Nevertheless, markers of coagulation and fibrinolytic potential are associated with CVD, ischaemic events, and cardiovascular mortality. Additionally, fibrinolytic potential is associated with other established CVD risk factors. Ischaemic events triggered by physical exertion are more likely to occur due to an occlusive thrombus, suggesting the exercise-induced responses related to haemostasis are of clinical significance. The magnitude of increase in coagulation potential, platelet aggregation and fibrinolysis appears to be primarily determined by exercise intensity. Patients with CVD may also have a larger increase in coagulation potential during acute exercise than healthy individuals. Additionally, the magnitude of the fibrinolytic response is largely related to the resting fibrinolytic profile of the individual. In particular, high resting plasminogen activator inhibitor-1 may diminish the magnitude of tissue plasminogen activator response during acute exercise. Therefore, acute responses to exercise may increase the risk of ischaemic event. However, chronic aerobic exercise training may decrease coagulation potential and increase fibrinolytic potential in both healthy individuals and CVD patients. Due to the aforementioned importance of resting fibrinolysis on the fibrinolytic response to exercise, chronic aerobic exercise training may cause favourable adaptations that could contribute to decreased risk for ischaemic event, both at rest and during physical exertion.