Phase Angle Adaptation to Exercise Training in Cancer Patients Undergoing Treatment

Phase angle is a measure of cellular resistance and reactance to bioelectrical impedance analysis. This measurement is useful as a marker of cell membrane integrity and is used as a prognostic marker in several clinical populations. Cancer and its related treatments impact cell membrane integrity, leading to poor cell function. Exercise is shown to increase phase angle, resulting in lowered risk of hospitalization and cardiovascular events. However, the effect of chronic exercise training on phase angle in the cancer population is unclear. Purpose: To assess the effect of chronic exercise on phase angle in cancer patients who are actively undergoing chemotherapy and/or radiation. Methods: A total of 56 cancer patients who were actively undergoing chemotherapy and/or radiotherapy were recruited to participate in a 12 week exercise-based rehabilitation program at the University of Northern Colorado Cancer Rehabilitation Institute. Each participant underwent an initial assessment of physiological parameters, including body composition and phase angle analysis. Results of this assessment were used to develop an individualized exercise prescription. Each participant received prescribed, supervised, one-on-one training from a Clinical Cancer Exercise Specialist, three times per week for one hour each session. After 12 weeks, each participant underwent a follow-up assessment of physiological parameters. Results: After 12 weeks of exercise training, significant increases in whole body (Initial: 4.55 ± 0.72, Follow-up: 4.68 ± 0.68; p = 0.02), right arm (Initial: 4.45 ± 0.76, Follow-up: 4.57 ± 0.72; p = 0.03), and left arm (Initial: 4.28 ± 0.79, Follow-up: 4.39 ± 0.75; p = 0.03) phase angle was observed. Conclusion: This study demonstrates that prescribed exercise training can increase phase angle in cancer survivors even while undergoing chemotherapy and/or radiation treatments. These changes may provide insight into the protective and rehabilitative benefits (e.g., cellular health, membrane integrity, disease risk) that exercise may have in this population

Relationships between Physiological and Self-Reported Assessment of Cancer-Related Fatigue

International Journal of Exercise Science 15(3): 177-190, 2022. The purpose of this study was to evaluate the relationships between subjective, self-reported cancer related fatigue (CRF) and objective measures of muscular strength and fatigability in cancer survivors. A total of 155 cancer survivors (60 ± 13 years of age) completed a questionnaire for the assessment of CRF, along with assessments of handgrip strength, quadriceps strength and fatigability (reduced force/torque). Fatigability was measured by completing 15 maximal isokinetic contractions of the knee extensors (QFI). Spearman’s rho correlation coefficients were calculated as pairwise combinations of the numerical and categorical dependent measures. Categorical variables were analyzed via nonparametric means of association. This included a 4x4 chi-square to test whether cancer stage (0–4) was independent of fatigue status (none, mild, moderate, severe) and whether cancer treatment (surgery, radiation, chemotherapy, or combinations of these) was independent of fatigue status. None of the physiological strength and fatigue measures were significantly correlated to overall perceived fatigue or any of the subscales. Cancer stage and treatment type were also not significantly related to fatigue status (likelihood ratio = .225, Cramer’s V = .228; likelihood ratio = .103, Cramer’s V = .369, respectively). Our results show that levels of patient reported fatigue severity were not significantly related to muscular fatigability or strength. As a result, cancer patients experiencing fatigue may benefit from following the standard exercise guidelines for cancer survivors, regardless of their levels of self-reported fatigue

Acute heart failure admissions in New South Wales and the Australian Capital Territory: the NSW HF Snapshot Study

Objective: The primary aim of the NSW Heart Failure (HF) Snapshot was to obtain a representative cross-sectional view of patients with acute HF and their management in New South Wales and Australian Capital Territory hospitals. Design and setting: A prospective audit of consecutive patients admitted to 24 participating hospitals in NSW and the ACT with a diagnosis of acute HF was conducted from 8 July 2013 to 8 August 2013. Results: A total of 811 participants were recruited (mean age, 77 ± 13 years; 58% were men; 42% had a left ventricular ejection fraction ≥ 50%). The median Charlson Comorbidity Index score was 3, with ischaemic heart disease (56%), renal disease (55%), diabetes (38%) and chronic lung disease (32%) the most frequent comorbidities; 71% of patients were assessed as frail. Intercurrent infection (22%), non-adherence to prescribed medication (5%) or to dietary or fluid restrictions (16%), and atrial fibrillation/flutter (15%) were the most commonly identified precipitants of HF. Initial treatment included intravenous diuretics (81%), oxygen therapy (87%), and bimodal positive airways pressure or continuous positive airways pressure ventilation (17%). During the index admission, 6% of patients died. The median length of stay in hospital was 6 days, but ranged between 3 and 12 days at different hospitals. Just over half the patients (59%) were referred to a multidisciplinary HF service. Discharge medications included angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (59%), β-blockers (66%) and loop diuretics (88%).Conclusions: Patients admitted to hospital with acute HF in NSW and the ACT were generally elderly and frail, with multiple comorbidities. Evidence-based therapies were underused, and there was substantial interhospital variation in the length of stay. We anticipate that the results of the HF Snapshot will inform the development of strategies for improving the uptake of evidence-based therapies, and hence outcomes, for HF patients

Acute Exercise Protects Against Doxorubucin Cardiotoxicity

Numerous methods have been used to minimize the cardiotoxic effects of the chemotherapeutic agent doxorubicin (DOX), and most have had limited success. Chronic endurance exercise has been shown to protect against DOX cardiotoxicity, but little is known regarding the effects of acute exercise on DOX-induced cardiac dysfunction. Purpose. The purpose of this study was to determine the effects of a single bout of acute endurance exercise on the cardiac dysfunction associated with DOX treatment. Methods. Male Sprague-Dawley rats either performed an acute exercise bout on a motorized treadmill for 60 minutes at a maximal speed of 25 m/min with a 5% grade (EX) or remained sedentary (SED) 24 hours before receiving either a 15-mg/kg DOX bolus dose or saline (SAL). Cardiac function was then analyzed 5 days post injection using a Langendorff isolated perfused heart model. In addition, myocardial lipid peroxidation was analyzed as an indicator of oxidative stress. Results. Doxorubicin treatment alone (SED+DOX) promoted a significant decline in end-systolic pressure (–35%), left ventricular developed pressure (–59%), and the maximal rate of left ventricular pressure development (–43%) as well as a 45% increase in lipid peroxidation products when compared with SED+SAL (P \u3c .05). Acute exercise 24 hours before DOX treatment, however, had a cardioprotective effect, as end-systolic pressure, left ventricular developed pressure, and the maximal rate of left ventricular pressure development were significantly higher in EX+DOX compared with SED+DOX (P \u3c .05) and EX+DOX had similar levels of lipid peroxidation products as SED+SAL Conclusions. An acute exercise bout performed 24 hours before DOX treatment protected against cardiac dysfunction, and this exercise-induced cardioprotection may partly be explained by a reduction in the generation of reactive oxygen species

The Gemini NICI Planet-Finding Campaign

Our team is carrying out a multi-year observing program to directly image and characterize young extrasolar planets using the Near-Infrared Coronagraphic Imager (NICI) on the Gemini-South 8.1-meter telescope. NICI is the first instrument on a large telescope designed from the outset for high-contrast imaging, comprising a high-performance curvature adaptive optics system with a simultaneous dual-channel coronagraphic imager. Combined with state-of-the-art observing methods and data processing, NICI typically achieves ~2 magnitudes better contrast compared to previous ground-based or space-based programs, at separations inside of ~2 arcsec. In preparation for the Campaign, we carried out efforts to identify previously unrecognized young stars, to rigorously construct our observing strategy, and to optimize the combination of angular and spectral differential imaging. The Planet-Finding Campaign is in its second year, with first-epoch imaging of 174 stars already obtained out of a total sample of 300 stars. We describe the Campaign's goals, design, implementation, performance, and preliminary results. The NICI Campaign represents the largest and most sensitive imaging survey to date for massive (~1 Mjup) planets around other stars. Upon completion, the Campaign will establish the best measurements to date on the properties of young gas-giant planets at ~5-10 AU separations. Finally, Campaign discoveries will be well-suited to long-term orbital monitoring and detailed spectrophotometric followup with next-generation planet-finding instruments.Comment: Proceedings of the SPIE, vol 7736 (Advances in Adaptive Optics, San Diego, CA, June 2010 meeting), in pres

Exercise Preconditioning Provides Long-Term Protection Against Early Chronic Doxorubicin Cariotoxicity

Acute doxorubicin (DOX) cardiotoxicity can be attenuated by exercise preconditioning, but little is known of whether this cardioprotection continues beyond 10 days post-DOX administration. The purpose of this study was to determine the effects of exercise preconditioning on early chronic DOX-induced cardiotoxicity. Male rats were randomly assigned to sedentary, treadmill, or wheel running groups. Treadmill and wheel running animals participated in a progressive treadmill training protocol or voluntary wheel running, respectively, for 10 weeks. Following the intervention, animals were further randomized to receive either DOX (sedentary + DOX, treadmill + DOX, wheel running + DOX) or saline (sedentary + saline, treadmill + saline, wheel running + saline). All animals then remained sedentary for 4 weeks. A 22% reduction in fractional shortening was observed in left ventricles from previously sedentary animals receiving DOX when compared with sedentary + saline. This degree of decline was not observed in treadmill + DOX and wheel running + DOX. Sedentary + DOX possessed significantly depressed mitral and aortic valve blood flow velocities when compared with sedentary + saline, but these decrements were not observed in treadmill + DOX and wheel running + DOX. Ex vivo analysis revealed that left ventricular developed pressure and maximal rate of pressure development were significantly lower in sedentary + DOX when compared to sedentary + saline. Treadmill and wheel running prior to DOX treatment protected against these decrements. Exercise cardioprotection was associated with preserved myosin heavy chain but not sarcoendoplasmic reticulum Ca2+ ATPase 2a expression. In conclusion, 10 weeks of prior exercise protected against early chronic DOX cardiotoxicity suggesting that training status may be a determining factor in the degree of late-onset cardiotoxicity experienced by cancer patients undergoing treatment with DOX

The Gemini NICI Planet-Finding Campaign: The Frequency of Giant Planets Around Debris Disk Stars

We have completed a high-contrast direct imaging survey for giant planets around 57 debris disk stars as part of the Gemini NICI Planet-Finding Campaign. We achieved median H-band contrasts of 12.4 mag at 0.5" and 14.1 mag at 1" separation. Follow-up observations of the 66 candidates with projected separation < 500 AU show that all of them are background objects. To establish statistical constraints on the underlying giant planet population based on our imaging data, we have developed a new Bayesian formalism that incorporates (1) non-detections, (2) single-epoch candidates, (3) astrometric and (4) photometric information, and (5) the possibility of multiple planets per star to constrain the planet population. Our formalism allows us to include in our analysis the previously known Beta Pictoris and the HR 8799 planets. Our results show at 95% confidence that 5MJup planet beyond 80 AU, and 3MJup planet outside of 40 AU, based on hot-start evolutionary models. We model the population of directly-imaged planets as d^2N/dMda ~ m^alpha a^beta, where m is planet mass and a is orbital semi-major axis (with a maximum value of amax). We find that beta 1.7. Likewise, we find that beta < -0.8 and/or amax < 200 AU. If we ignore the Beta Pic and HR 8799 planets (should they belong to a rare and distinct group), we find that 3MJup planet beyond 10 AU, and beta < -0.8 and/or alpha < -1.5. Our Bayesian constraints are not strong enough to reveal any dependence of the planet frequency on stellar host mass. Studies of transition disks have suggested that about 20% of stars are undergoing planet formation; our non-detections at large separations show that planets with orbital separation > 40 AU and planet masses > 3 MJup do not carve the central holes in these disks.Comment: Accepted to ApJ on June 24, 2013. 67 pages, 17 figures, 12 table

Precision Astrometry of a Sample of Speckle Binaries and Multiples with the Adaptive Optics Facilities at the Hale and Keck II Telescopes

Using the adaptive optics facilities at the 200-in Hale and 10-m Keck II, we observed in the near infrared a sample of 12 binary and multiple stars and one open cluster. We used the near diffraction limited images of these systems to measure the relative separations and position angles between their components. In this paper, we investigate and correct for the influence of the differential chromatic refraction and chip distortions on our relative astrometric measurements. Over one night, we achieve an astrometric precision typically well below 1 miliarcsecond and occasionally as small as 40 microarcseconds. Such a precision is in principle sufficient to astrometrically detect planetary mass objects around the components of nearby binary and multiple stars. Since we have not had sufficiently large data sets for the observed sample of stars to detect planets, we provide the limits to planetary mass objects based on the obtained astrometric precision.Comment: 18 pages, 8 figures, 9 tables, to appear in MNRA