Search results for "circulatory and respiratory physiology"
showing 10 items of 329 documents
Phrenic nerve displacement by intrapericardial balloon inflation during epicardial ablation of ventricular tachycardia: Four case reports
2020
BACKGROUND Phrenic nerve (PN) injury is one of the recognized possible complications following epicardial ablation of ventricular tachycardia (VT). High-output pacing is a widely used maneuver to establish a relationship between the PN and the ablation catheter tip. An absence of PN capture is usually considered an indication that it is safe to ablate, and that successful ablation may be performed at adjacent sites. However, PN capture may impact the procedural outcome. Only a few cases have been reported in the literature that avoid PN injury by using different techniques. CASE SUMMARY Three patients with a previous history of myocarditis and one patient with ischemic cardiomyopathy underw…
Spontaneous Nocturnal Erections - Physiology and Clinical Applications. Spontane nachtliche Erektionen - Physiologie und klinische Anwendungen
2005
Spontaneous nocturnal erections in men are a well-known phenomenon whose physiology however is not yet really understood. The measurement of nocturnal erections has gained clinical relevance for the diagnosis of erectile dysfunction because it allows an objective and quantitative assessment of the erectile capacity. A decisive advantage compared to other diagnostic tests carried out during wakefulness is the exclusion of psychological factors to a great extent. Thus, an evaluation of the organic component of an erectile dysfunction is possible. Regarding the interpretation of nocturnal erection records, various factors possibly influencing the results must be considered; this is particularl…
Normal Values of Oxygen Concentration in Human Blood
1984
Under physiological conditions, the oxygen supply as the product of O2-concentration (mlO2/dl; %(v/v)) and perfusion is influenced by many factors (cf. Fig. 1): perfusion on one hand, oxygen partial pressure (pO2; mmHg), haemoglobin (Hb) concentration (g/dl) and O2 binding power of Hb on the other hand. Under pathological conditions, oxygen supply disturbances are related to hypoxemia, i.e. reduction of O2-concentration in the blood. The differential diagnosis of hypoxemia includes normoxic, hypoxic and circulatoric disturbances of oxygen supply (cf. Fig. 1). Thus it is necessary to describe a NORMOXIC HYPOXEMIA (anemic or toxemic), a HYPOXIC HYPOXEMIA (decreased O2-concentration caused by …
Effects of severe arterial hypocapnia on regional blood flow regulation, tissuePO2 and metabolism in the brain cortex of cats
1981
The effect of a stepwise decrease in PaCO2 from 3.9-1.6 kPa on rCBF, rCMRO2, tissue PO2 and concentrations of glucose, lactate, pyruvate, ATP, ADP, AMP and phosphocreatine in the brain cortex was studied in cats lightly anaesthetized with sodium pentobarbital. 1. Moderate lowering of PaCO2 to 2.5 kPa induced in all animals a homogeneous decrease of rCBF in corresponding areas of the right and left hemisphere. Mean rCBF fell from 129.2 to 103.1 ml X 100 g-1 X min-1, while rCMRO2 remained unchanged (12.7-12.9 ml X 100 g-1 X min-1). The tissue PO2 frequency histograms showed a shift to lower values without indicating the presence of brain tissue hypoxia. 2. Severe arterial hypocapnia (PaCO2 = …
The Role of Heart Rate on the Associations Between Body Composition and Heart Rate Variability in Children With Overweight/Obesity: The ActiveBrains …
2019
The authors would like to thank all the participants who volunteered for this investigation. This work is the part of a Ph.D. Thesis conducted in the Biomedicine Doctoral Studies of the University of Granada, Spain.
Apoptotic role of Fas/Fas ligand system in the regulation of erythropoiesis
1999
Abstract The possible involvement of Fas and Fas ligand (FasL) in the regulation of erythropoiesis was evaluated. Immunohistochemistry of normal bone marrow specimens revealed that several immature erythroblasts undergo apoptosis in vivo. Analysis of bone marrow erythroblasts and purified progenitors undergoing unilineage erythroid differentiation showed that Fas is rapidly upregulated in early erythroblasts and expressed at high levels through terminal maturation. However, Fas crosslinking was effective only in less mature erythroblasts, particularly at basophilic level, where it induced apoptosis antagonized by high levels of erythropoietin (Epo). In contrast, FasL was selectively induced…
Causal analysis of short-term cardiovascular variability: state-dependent contribution of feedback and feedforward mechanisms.
2016
Baroreflex function is usually assessed from spontaneous oscillations of blood pressure (BP) and cardiac RR interval assuming a unidirectional influence from BP to RR. However, the interaction of BP and RR is bidirectionalâRR also influences BP. Novel methods based on the concept of Granger causality were recently developed for separate analysis of feedback (baroreflex) and feedforward (mechanical) interactions between RR and BP. We aimed at assessing the proportion of the two causal directions of the interactions between RR and systolic BP (SBP) oscillations during various conditions, and at comparing causality measures from SBP to RR with baroreflex gain indexes. Arterial BP and ECG sig…
Multiscale Information Decomposition Dissects Control Mechanisms of Heart Rate Variability at Rest and During Physiological Stress.
2019
Heart rate variability (HRV
Thromboxane biosynthesis, neutrophil and coagulative activation in type IIa hypercholesterolemia
1995
SummaryThromboxane (Tx) A2 biosynthesis is enhanced in the majority of patients with type IIa hypercholesterolemia. Because blood clotting activation is an important component of the inflammatory response, involved in the initiation and progression of atherosclerotic plaques, we have investigated TxA2 biosynthesis, neutrophil activation and thrombin generation in 24 patients with type IIa hypercholesterolemia.Urinary 11-dehydro-TxB2, was significantly higher (p =0.0001) in patients than in 24 sex- and age matched healthy subjects. Similarly, prothrombin fragment 1+2 (F1+2), thrombin-antithrombin III complexes and plasma elastase were significantly higher in patients than incontrols. Urinary…
Lung Injury Is a Predictor of Cerebral Hypoxia and Mortality in Traumatic Brain Injury
2020
Background: A major contributor to unfavorable outcome after traumatic brain injury (TBI) is secondary brain injury. Low brain tissue oxygen tension (PbtO2) has shown to be an independent predictor of unfavorable outcome. Although PbtO2 provides clinicians with an understanding of the ischemic and non-ischemic derangements of brain physiology, its value does not take into consideration systemic oxygenation that can influence patients' outcomes. This study analyses brain and systemic oxygenation and a number of related indices in TBI patients: PbtO2, partial arterial oxygenation pressure (PaO2), PbtO2/PaO2, ratio of PbtO2 to fraction of inspired oxygen (FiO2), and PaO2/FiO2. The primary aim …