Search results for " volume"

Electromyographic activity related to aerobic and anaerobic threshold in ergometer bicycling

1985

Electromyographic activity (EMG) of the knee extensor musculature (m. vastus lateralis, m. vastus medialis, m. rectus femoris), triceps surae (m. gastrocnemius, m. soleus) and m. tibialis anterior was studied in ergometer bicycling at five different power outputs around aerobic (AerT) and anaerobic (AnT) thresholds. EMGs were sampled with surface electrodes for ten revolutions at the beginning, in the middle and at the end of each work load and integrated (IEMG) separately for each of the muscles and for the descending (work) and ascending (rest) phase of the revolution. The mean power frequency (MPF) of the power spectral density function for the descending periods was also calculated. The…

Non-arbitrary minimum threshold of yearly performed pancreatoduodenectomies: National multicentric study

2021

Abstract Background Annual hospital volume of pancreatoduodenectomies could influence postoperative outcomes. The aim of this study is to establish with a non-arbitrary method the minimum threshold of yearly performed pancreatoduodenectomies in order to improve several postoperative quality outcomes. Method Prospective follow-up of patients submitted to pancreatoduodenectomy in participating hospitals during 1 year. The influence of hospital volume on quality outcomes was analyzed by univariable and multivariable models. The minimum threshold of yearly performed pancreatoduodenectomies to improve outcomes was established by Akaike’s information criteria. Results Data from 877 patients opera…

Ventilatory responses to imagined exercise.

1996

We studied whether the ventilatory responses to imagined exercise are influenced by automatic processes. Twenty-nine athletes produced mental images of a sport event with successive focus on the environment, the preparation, and the exercise. Mean breathing frequency increased from 15 to 22 breaths/min. Five participants reported having voluntarily controlled breathing, two of them during preparation. Twenty participants reported that their breathing pattern changed during the experiment: 11 participants were unable to correctly report on the direction of changes in frequency, and 13 incorrectly reported changes in amplitude. This finding suggests that these changes were not voluntary in mo…

Human corticotropin-releasing factor (hCRF) is a potent respiratory analeptic. Physiological and clinical aspects.

1986

During intravenous corticotropin-releasing factor stimulation tests we observed a deepening of the tidal volume in 35 patients. To investigate this presumed respiratory stimulation we measured respiratory parameters in 12 healthy male volunteers in a single-blind placebo-controlled trial. The intravenous 60-s infusion of 100 micrograms of human corticotropin-releasing factor induced a very potent respiratory stimulation in every subject: respiratory minute volume (mean +/- S.D.) increased by 81% from 6.319 +/- 0.577 to 11.464 +/- 1.264 liters per min (P less than 0.001), whereas there was only a slight rise in the mean respiratory rate from 12.4 +/- 3.0 to 14.7 +/- 2.7 breaths per min (P le…

Human Corticotropin-Releasing Hormone in Man: Dose-Response of Minute Ventilation and End-Tidal Partial Pressures of Carbon Dioxide and Oxygen*

1987

The respiratory stimulant properties of iv injections of 33, 67, and 100 micrograms synthetic human corticotropin-releasing hormone (hCRH) were studied in 12 normal men in a single blind, placebo-controlled trial. All doses of hCRH induced a respiratory stimulation in every subject, and the stimulation was dose dependent. The onset of respiratory stimulation occurred within 15-30 sec after hCRH infusion was started. Initially, there was an increase in tidal volume (VT), followed by an increase in respiratory rate. The maximum minute ventilation (VE) occurred 60-120 sec after starting the injection. The 33-micrograms hCRH dose induced a 35% increase in VE from 6.3 +/- 0.6 (+/- SD) to 9.7 +/-…

Rationale, design and baseline characteristics of the MyoVasc study: A prospective cohort study investigating development and progression of heart fa…

2020

Abstract Background Heart failure (HF) is a poly-aetiological syndrome with large heterogeneity regarding clinical presentation, pathophysiology, clinical outcome and response to therapy. The MyoVasc study (NCT04064450) is an epidemiological cohort study investigating the development and progression of HF. Methods The primary objective of the study is (a) to improve the understanding of the pathomechanisms of HF across the full spectrum of clinical presentation, (b) to investigate the current clinical classifications of HF, and (c) to identify and characterize homogeneous subgroups regarding disease development using a systems-oriented approach. Worsening of HF, that is, the composite of tr…

Left ventricular filling abnormalities and obesity-associated hypertension: relationship with overproduction of circulating transforming growth facto…

2005

This study has been designed to evaluate the relationship among transforming growth factor beta1 (TGFbeta1) and some measurements of diastolic function in a population of hypertensive subjects with normal left ventricular ejection fraction. We studied 67 hypertensive outpatients who according to their BMI levels were subdivided into three groups: lean (L), overweight (OW) and obese (OB) hypertensives (HT). Circulating TGFbeta1 and M- and B-mode echocardiography was determined. All hypertensives were further subgrouped, according to European Society of Cardiology Guidelines, into two subsets of patients with normal diastolic function or with diastolic dysfunction. Prevalence of left ventricu…

Higher blood eosinophil levels after omalizumab treatment may be associated with poorer asthma outcomes

2019

Left ventricular ejection fraction calculation from automatically selected and processed diastolic and systolic frames in short-axis cine-MRI

2005

International audience; Abstract: The calculation of the left ventricular ejection fraction (LVEF) is dependent upon the accurate measurement of diastolic and systolic left ventricular volumes. Although breath-hold cine magnetic resonance imaging (MRI) allows coverage of the whole cardiac cycle with an excellent time resolution, many authors rely on the visual selection of diastolic and the systolic short-axis slices in order to reduce the postprocessing time. An automatic method was developed to detect the endocardial contour on each image, allowing an automatic selection of the systolic frame. The calculated ejection fraction was compared with radionuclide ventriculography (RNV). Sixty-fi…

Microcentrifuge or Automated Hematological Analyzer to Assess Hematocrit in Exercise? Effect on Plasma Volume Loss Calculations

2016

The assessment of plasma volume loss (∆PV) induced by exercise can be estimated from changes in hematocrit (Htc) and hemoglobin (Hb), and it is essential when investigating the metabolic or biologic response to exercise of circulating biomarkers. We aimed to ascertain whether the estimation of ∆PV may differ when Hb and Htc are determined by automated hematological analyzer (AHA) versus manual methods. Twenty-five healthy male subjects performed a maximal running incremental exercise. Blood samples were taken before exercise, immediately after exercise, and after a 30-min recovery. Hb and Htc (Htc-AHA) were determined by an AHA. Htc was also determined by microcentrifugation (Htc-M). The ∆P…