Search results for "cycle"

Respiratory Mechanics and Gas Exchange in Thoracic Surgery: Changes in Classical Knowledge in Respiratory Physiology

2020

Respiratory mechanics describe the lung function through pressure and flow and the interplay between the two during the respiratory cycle. Derived indices are volume, compliance and resistance (Hess, Respir Care 59(11):1773–1794, 2014). Thoracic surgery in most cases requires the separation of the lungs in order to allow surgery of or near one lung and ventilation of the other lung, while the perfusion to the non-ventilated lung is continued. This has profound implications for the gas exchange and respiratory mechanics.

Metabolic changes in the rat liver during pregnancy

1983

During pregnancy the rat liver shows alterations in metabolism which apparently do not to occur in the non-pregnant animal. In our study, the following metabolite concentrations and enzyme activities in the liver of pregnant and non-pregnant rats were measured after fasting periods of 6 and 12 h: malate, fumarate, isocitrate, alpha-keto-glutarate, glutamate, malate-dehydrogenase, fumarate-hydratase, glutamate-dehydrogenase, isocitrate-dehydrogenase, aspartate-aminotransferase and after 12 h fast, the concentrations of acetyl coenzyme A and citrate. These results are discussed with regard to their possible importance for the maternal and fetal energy supply.

Respuesta de preosteoblastos a compuestos de estroncio o calcio: proliferación, diferenciación, mineralización y respuesta génica global

2013

Fundamento: Los mecanismos que desencadenan la osteogénesis todavía no están aclarados. El objetivo de este estudio fue valorar el papel de estroncio y calcio, aportados en distinto soporte molecular, como inductores de distintos mecanismos de estímulo osteoblástico, incluyendo proliferación, diferenciación y mineralización de células preosteoblásticas. Se investigó también la respuesta global genómica con la técnica de microarray. Métodos: Se diseñó un estudio experimental con células pre-osteoblásticas murinas MC3T3-E1, que fueron estimuladas durante 3 horas y 7 días. Se realizaron estudios bioquímicos y de expresión génica del genoma de ratón (Affymetrix). Resultados: El estroncio unido …

A girl with an atypical form of ataxia telangiectasia and an additional de novo 3.14Mb microduplication in region 19q12

2011

A 9-year-old girl born to healthy parents showed manifestations suggestive of ataxia telangiectasia (AT), such as short stature, sudden short bouts of horizontal and rotary nystagmus, a weak and dysarthric voice, rolling gait, unstable posture, and atactic movements. She did not show several cardinal features typical of AT such as frequent, severe infections of the respiratory tract. In contrast, she showed symptoms not generally related to AT, including microcephaly, profound motor and mental retardation, small hands and feet, severely and progressively reduced muscle tone with slackly protruding abdomen and undue drooling, excess fat on her upper arms, and severe oligoarthritis. A cranial…

Perturbed Glucose Metabolism: Insights into Multiple Sclerosis Pathogenesis

2014

Multiple sclerosis (MS) is a complex debilitating disease of the central nervous system perceived to result from the autoimmune effect of T cells in damaging myelin sheath. However, the exact pathogenesis of the disease remains elusive. Initial studies describing the possibility of defective pyruvate metabolism in MS were performed in 1950s. The group observed elevated blood pyruvate level in both fasting and postprandial times in MS patients with relapse. Similarly, other investigators also reported increased fasting pyruvate level in this disease. These reports hint to a possible abnormality of pyruvate metabolism in MS patients. In addition, increase in levels of Krebs cycle acids like a…

The cardinal exercise stopper: Muscle fatigue, muscle pain or perception of effort?

2018

The capacity to sustain high-intensity aerobic exercise is essential for endurance performance. Therefore, it is important to understand what is the factor limiting time to exhaustion (TTE) in healthy and fit adults. In Study 1, maximal voluntary cycling power (MVCP) was measured in 11 volunteers before and immediately after a high-intensity TTE test on cycle ergometer. Cadence was 60 rpm in both the MVCP and TTE tests. Despite a 35% loss in MVCP, power produced during the final MVCP test (mean ± SD 469 ± 111 W) was significantly higher than the power required by the TTE test (269 ± 55 W) (P < 0.001). In Study 2, 12 participants performed a cold pressor test (CPT) to the limit of tolerance …

O069. Menstrual cycle affects cortical excitability differently in females with migraine and in healthy controls: a new perspective by cross modal so…

2015

The sound-induced flash illusions (SIFI) represent a valid tool to explore multimodal perception and are critically dependent on visual and acoustic cortical excitability [1, 2]. In a previous study [3], we observed a significant reduction of illusions in migraine patients with respect to healthy controls, probably due to a condition of visual cortex hyperexcitability. Aim of the present study was to evaluate SIFI perceptions in healthy women and patients with menstrual migraine and to describe the effects of cyclical change of steroid hormones and cortical responsiveness.

2021

The purpose of this study was to investigate the prevalence of self-reported restrictive eating, current or past eating disorder, and menstrual dysfunction and their relationships with injuries. Furthermore, we aimed to compare these prevalences and associations between younger (aged 15–24) and older (aged 25–45) athletes, between elite and non-elite athletes, and between athletes competing in lean and non-lean sports. Data were collected using a web-based questionnaire. Participants were 846 female athletes representing 67 different sports. Results showed that 25%, 18%, and 32% of the athletes reported restrictive eating, eating disorders, and menstrual dysfunction, respectively. Higher ra…

Shot placement within cardiac cycle in junior elite rifle shooters

2007

Abstract Objectives This study examined the timing of the trigger pull in relation to the cardiac cycle during skilled precision shooting. Methods Electrocardiogram was recorded from 20 junior level competitive air-rifle shooters in two separate sessions. The testing was conducted at an indoor shooting range using an optoelectronic shooting system. The experimental task was to fire a shot in the standing position at a distance of 10 m from the target. Results The results showed that the junior level shooters fired more often during the phase of 10–15% of the R wave-to-R wave (R–R) interval. With regards to the accuracy of performance, there was not any optimal location for triggering in the…

The effect of hormone replacement therapy and/or exercise on skeletal muscle attenuation in postmenopausal women: a yearlong intervention

2005

Hormone replacement therapy (HRT) has been reported to exert a positive effect on preserving muscle strength following the menopause, however, the mechanism of action remains unclear. We examined whether the mechanism involved preservation of muscle composition as determined by skeletal muscle attenuation. Eighty women aged 50-57 years were randomly assigned to either: HRT, exercise (Ex), HRT + exercise (ExHRT), and control (Co) for 1 year. The study was double-blinded with subjects receiving oestradiol and norethisterone acetate (Kliogest) or placebo. Exercise included progressive high-impact training for the lower limbs. Skeletal muscle attenuation in Hounsfield units (HU) was determined …