Cardiovascular responses during rest-exercise and exercise-exercise transients

If indeed vagal withdrawal determines the rapid response to exercise (phase I), the a large reduction, if not complete suppression, of phase I should be found, when an exercise transient starts from a previous lower steady state exercise rather than from rest. On 15 healthy young subjects we measured beat-by-beat cardiac output (Q̇, Modelflow from Portapres data) and heart rate (fH, ECG) during these cycle ergometer exercise transients: 0–50 W (transient from rest, RT) and 50–100W (transient from exercise, ET). A double exponential was used to compute amplitudes and time constants of phase I and II (A1 and A2; T1 and T2). At steady state, fH was 87.510.4, 109.312.0, and 139.617.1bpm, and Q̇ was 7.31.5, 12.61.6, and 16,11,9L/min, at rest, 50W and 100W, respectively. In RT, A1 and A2 for fH were 11.78.6 and 11.34.7bpm; the corresponding T1 and T2 were 1.61.9 and 14.421.3s. For Q̇, we had: A1=4.01.8L/min, A2=1.51.4L/min, T1=3.21.8s, T2=11.312.2s. In ET, the double exponential model provided preposterous A1 and T1 values and extremely high T2 values (>100s). Subsequent use of a mono exponential model provided, for fH, A=29.78.9bpm and T=7.74.9s, and for Q̇, A=3.58.6L/min, and T=7.05.7s. The A and T in ET did not differ from the A2 and T2 of RT. We conclude that a single exponential model is more adequate to describe ET and this single exponential corresponds to the second exponential of RT. Our results are compatible with the vagal withdrawal hypothesis

LIFESTYLE ASSESSMENT AND IMPROVEMENT WITH FOCUS ON LEISURE TIME PHYSICAL ACTIVITY AMONG UNIVERSITY STUDENTS: THE #STUDIOXLAVITA PROJECT

INTRODUCTION: Sedentariness, smoking, alcohol abuse and unbalanced feeding are harmful for health, leading to chronic diseases and increasing mortality rate. For young adults, University is a new social and cultural context: parents’ imprinting could be easily altered, new lifestyles take shape and personal choices emerge. Intervention programmes to advance awareness on harmful lifestyle and promote healthy habits are essential. The #studioxlavita project, launched in 2016 by the University of Brescia with these purposes, investigated students’ lifestyle, with special emphasis on physical activity . METHODS: We developed two consecutive facultative surveys, of 15 <1st level> and 52 items <2nd level>, addressed to all the University’s students. Questions were about leisure time physical activity , use of fitness technology, relationship with friends, classmates and parents, feed, physical appearance, body self-perception, physical and mental health, use of certain substances or products , night-time rest and beliefs concerning healthy behaviours. In the 2nd level survey we also adopted the Kessler Psychological Distress Scale and the short form of the International Physical Activity Questionnaire to estimate the amount of PA carried out in the last 7 days. Students who filled in both questionnaires received a personal report including the aggregate data analysis, a comparison with other investigations and indications about healthy habits, according to recommendations and guidelines. RESULTS: 3,436 out of 15,688 students filled in the1st level survey. Of them, 778 accepted to participate in the 2nd level survey, and 456 completed it. 1st level survey revealed that 72% of the students practised LTPA <45% regularly and 27% occasionally>. LTPA is largely performed <44% of the student> in non-competitive form, with recreational and/or health purposes. According to IPAQ-SF categorical score, 24%, 34% and 42% of the students performed low, moderate and high levels of PA, respectively. In 2st level survey, 76% of the students wished to practise more PA; 42% would participate in practical sport courses. CONCLUSION: University is an ideal setting for promoting lifestyle change among a captive audience. Intervention programs to increment PA are acclaimed by students. The students from University of Brescia reported higher LTPA practice than the national average people between 18 and 34 years <47%, data from Italian National Institute of Statistics, 2015>, although this parameter was assessed with different methods

EFFECTS OF PHYSICAL ACTIVITY PROMOTION AMONG UNIVERSITY STUDENTS: THE #STUDIOXLAVITA PROJECT

INTRODUCTION: Sedentariness is a major health problem in our time and physical activity promotion is an imperative commitment for healthcare systems. Recommendations from WHO indicate a minimum of 150 minutes of moderate intensity aerobic exercise as weekly standard for adults. Strategies to increment PA practice are implemented in different settings, such as house care, school, University and workplace. The project #studioxlavita <#SXLV> was launched by the University of Brescia in 2016 with the aim of collecting data about undergraduates lifestyle and encourage healthy behaviours. In particular we focused on PA assessment and promotion in a Universitybased setting. METHODS: Two consecutive surveys were sent to all students . Q0 included the short form of the International Physical Activity Questionnaire , the Kessler Psychological Distress Scale and additional questions on several lifestyle aspects. Among responders, we selected 40 students who agreed to take part in one of the following 15-week practical sport courses: ultimate frisbee, muscle strengthening and dance fitness. Before and after being engaged in practical sport courses, students underwent cardiopulmonary exercise test and skinfold thickness measurements, in order to assess peak oxygen consumption and percent body fat . Finally, to assess possible lifestyle changes, we sent them additional surveys at the end of the practical sport courses and 30 days after . Paired t-test was used to analyse significant differences. RESULTS: 27 students <16 female, 11 male; age: 22.7±3.7> concluded sport activity courses and filled in Q1. Of them, 20 completed also Q2. Overall courses attendance was 57%. At T1 , normalized Q̇O2peak increased with respect to T0 <37.0±6.9 vs 35.2±7.4 ml/min/Kg, p=0.03>. Conversely, percent body fat decreased <16.5±6.4 vs 18.3±7.5, p=0.01>. In Q1, 20 students declared to have a more active lifestyle since the beginning of the courses. In Q2, IPAQ-SF-derived total weekly energy expenditure was higher than in Q0, although not significant <5,839 ±7,035 MET*min vs 2,770±2,457 MET*min, p=0.1>. Q2 showed a reduced K6 scale score with respect to Q0 <13.8±4.6 vs 15.8±4.9, p=0.03>. CONCLUSION: With the sport activity courses established in #SXLV we gave students the opportunity to comply with WHO recommendations. After courses, they appeared to practice more PA, have a higher maximal aerobic capacity, a lower percent body fat and a lower grade of psychological distress than before courses. Simple activities as those proposed by #SXLV are sufficient to reduce sedentariness and improve the quality of life of student

Navigation-guided osteotomies improve margin delineation in tumors involving the sinonasal area: A preclinical study

Objectives: To demonstrate and quantify, in a preclinical setting, the benefit of three-dimensional (3D) navigation guidance for margin delineation during ablative open surgery for advanced sinonasal cancer. Materials and methods: Seven tumor models were created. 3D images were acquired with cone beam computed tomography, and 3D tumor segmentations were contoured. Eight surgeons with variable experience were recruited for the simulation of osteotomies. Three simulations were performed: 1) Unguided, 2) Guided using real-time tool tracking with 3D tumor segmentation (tumor-guided), and 3) Guided by 3D visualization of both the tumor and 1-cm margin segmentations (margin-guided). Analysis of cutting planes was performed and distance from the tumor surface was classified as follows: “intratumoral” when 0 mm or negative, “close” when greater than 0 mm and less than or equal to 5 mm, “adequate” when greater than 5 mm and less than or equal to 15 mm, and “excessive” over 15 mm. The three techniques (unguided, tumor-guided, margin-guided) were statistically compared. Results: The use of 3D navigation for margin delineation significantly improved control of margins: unguided cuts had 18.1% intratumoral cuts compared to 0% intratumoral cuts with 3D navigation (p < 0.0001). Conclusion: This preclinical study has demonstrated the significant benefit of navigation-guided osteotomies for sinonasal tumors. Translation into the clinical setting – with rigorous assessment of oncological outcomes – would be the proposed next step

Treatment of loco-regional recurrence of nasopharyngeal carcinoma in a non-endemic area: oncologic outcomes, morbidity, and proposal of a prognostic nomogram

Introduction: The study assessed outcomes and toxicities of different treatment modalities for local and/or regional recurrent nasopharyngeal carcinoma (NPC) in a non-endemic area. Methods: Patients treated with curative intent for recurrent NPC with salvage surgery, photon-based radiotherapy, proton therapy (PT), with or without chemotherapy, at different Italian referral centers between 1998 and 2020 were included. Adverse events and complications were classified according to the Common Terminology Criteria for Adverse Events. Characteristics of the patients, tumors, treatments, and complications are presented along with uni- and multivariate analysis of prognostic factors. A survival predictive nomogram is also provided. Results: A total of 140 patients treated from 1998 to 2020 were retrospectively assessed. Cases with lower age, comorbidity rate, stage, and shorter disease-free interval (DFI) preferentially underwent endoscopic surgery. More advanced cases underwent re-irradiation, fairly distributed between photon-based radiotherapy and PT. Age and DFI were independent factors influencing overall survival. No independent prognostic effect of treatment modality was observed. No significant difference in the morbidity profile of treatments was observed, with 40% of patients experiencing at least one adverse event classified as G3 or higher. Conclusion: Recurrent NPC in a non-endemic area has dissimilar aspects compared to its endemic counterpart, suggesting the need for further studies that can guide the choice of the best treatment modality

A regression method for the power–duration relationship when both variables are subject to error

Purpose: The power–duration relationship has been variously modelled, although duration must be acknowledged as the dependent variable and is supposed to represent the only source of experimental error. However, there are certain situations, namely extremely high power outputs or outdoor field conditions, in which the error in power output measurement may not remain negligible. The geometric mean (GM) regression method deals with the assumption that also the independent variable is subject to a certain amount of experimental error, but has never been utilized in this context. Methods: We applied the GM regression method for the two- and three-parameter critical power models and tested it against the usual weighted least square (WLS) procedure with our previous published data. Results: There were no significant differences between parameter estimates of WLS and GM. Bias and limit of agreements between the two methods were low, while correlation coefficients were high (0.85–1.00). Conclusions: GM provided equivalent results with respect to WLS in fitting the critical power model to experimental data and for its conceptual characteristics must be preferred wherever concerns on the precision of P measurement are present, such as for in-field power meters

Vagal blockade suppresses the phase I heart rate response but not the phase I cardiac output response at exercise onset in humans

Purpose: We tested the vagal withdrawal concept for heart rate (HR) and cardiac output (CO) kinetics upon moderate exercise onset, by analysing the effects of vagal blockade on cardiovascular kinetics in humans. We hypothesized that, under atropine, the φ1 amplitude (A1) for HR would reduce to nil, whereas the A1 for CO would still be positive, due to the sudden increase in stroke volume (SV) at exercise onset. Methods: On nine young non-smoking men, during 0–80 W exercise transients of 5-min duration on the cycle ergometer, preceded by 5-min rest, we continuously recorded HR, CO, SV and oxygen uptake (V˙ O2) upright and supine, in control condition and after full vagal blockade with atropine. Kinetics were analysed with the double exponential model, wherein we computed the amplitudes (A) and time constants (τ) of phase 1 (φ1) and phase 2 (φ2). Results: In atropine versus control, A1 for HR was strongly reduced and fell to 0 bpm in seven out of nine subjects for HR was practically suppressed by atropine in them. The A1 for CO was lower in atropine, but not reduced to nil. Thus, SV only determined A1 for CO in atropine. A2 did not differ between control and atropine. No effect on τ1 and τ2 was found. These patterns were independent of posture. Conclusion: The results are fully compatible with the tested hypothesis. They provide the first direct demonstration that vagal blockade, while suppressing HR φ1, did not affect φ1 of CO