Search results for "ARTERIAL"
showing 10 items of 714 documents
The Significance of Low O2-Tensi0ns in the Brain Cortex for Occurrence of Metabolic Alterations under Critical Flow Conditions
1985
A reduction in the 02 supply to the brain cortex leads to O2 deficiency and curtailment of neuronal metabolism and function as soon as a minimal cellular O2 tension of 0.1 – 1 mmHG (13 – 133 Pa) can no longer be maintained (Chance et al., 1964; Grote 1967). The hypoxia-induced metabolic alterations are characterized by decreased tissue levels of the energy-rich phosphate compounds PCr and ATP. In addition, elevated concentrations of lactate, pyruvate and NADH and an increase in the lactate/pyruvate ratio and in the NADH/NAD+ ratio are to be expected (Duffy et al., 1972; Granholm and Siesjo 1969; Granholm et al., 1969; Granholm and Siesjo 1971; Grote 1978; Grote and Schubert 1982; Norberg an…
Photoplethysmography Analysis of Artery Properties in Patients with Cardiovascular Diseases
2008
In this study arterial parameters of healthy subjects were compared to those of patients with cardiovascular diseases. The photoplethysmography (PPG) measurements of blood volume pulsations have been performed. Using a novel algorithm for analysis of simultaneously measured ear and finger PPG signals, arterial parameters were evaluated in representative groups of healthy subjects and patients with cardiovascular diseases. Digital volume pulse (DVP), pulse cycle duration (T), augmentation index (AIx), reflection index (RI) and transit time of reflected wave (RTT) were evaluated in every heartbeat cycle. Correlations between the AIx and RI, T and RTT, AIx and standard deviation of AIx, RTT an…
Critical limb ischaemia: definition and natural hystory
2004
The term critical limb ischemia refers to a condition characterized by chronic ischemic at-rest pain, ulcers, or gangrene in one or both legs attributable to objectively proven arterial occlusive disease. Critical limb ischemia implies chronicity and is to be distinguished from acute limb ischemia. Its incidence is approximately 500 to 1000 per million year, with the highest rates among older subjects, smokers and diabetics. The rate of primary amputation ranges from 10% to 40%, and was performed only when no graftable distal vessels were present, or in neurologically impaired or hopelessly nonambulatory patients. Contrarily, in some highly specialized and aggressive centres about 90% of pa…
Respuesta emocional de ira y alteraciones del lenguaje en pacientes con esquizofrenia
2015
Los pacientes con esquizofrenia presentan alteraciones en el procesamiento emocional especialmente en la expresión, y en el reconocimiento de emociones. Sin embargo, se ha investigado poco cómo experimentan las emociones los pacientes con esquizofrenia y en concreto existe una literatura muy escasa sobre la respuesta cardiovascular, hormonal o de la activación asimétrica cerebral. Por otro lado, la ira es clave en la conducta agresiva, y en el caso de la esquizofrenia parece estar mediada por síntomas psicóticos como las alucinaciones y los delirios. Basándonos, pues, en la respuesta emocional anómala que pueden presentar las personas con esquizofrenia en general, y los pacientes con alucin…
Evaluación cardiometabólica y adrenérgica en el sujeto obeso sano joven
2021
ANTECEDENTES: La obesidad se define como un exceso de peso del individuo, entendiendo como tal el exceso de contenido graso en el cuerpo. Actualmente la OMS sitúa a la obesidad como la epidemia del siglo XXI. La obesidad incrementa el riesgo de diabetes, hipertensión, enfermedad coronaria, ictus y ciertos tipos de cáncer. Independientemente del mecanismo primario responsable de la obesidad existen un serie de mecanismos que se encuentran interrelacionados y que llevan a la aparición de: I) Alteraciones metabólicas del metabolismo hidrocarbonado y lipídico, con el consiguiente incremento del riesgo de desarrollar diabetes mellitus tipo 2, II) alteraciones precoces en el sistema cardiovascula…
Feasibility of Ultra-Short-Term Analysis of Heart Rate and Systolic Arterial Pressure Variability at Rest and during Stress via Time-Domain and Entro…
2022
Heart Rate Variability (HRV) and Blood Pressure Variability (BPV) are widely employed tools for characterizing the complex behavior of cardiovascular dynamics. Usually, HRV and BPV analyses are carried out through short-term (ST) measurements, which exploit ~five-minute-long recordings. Recent research efforts are focused on reducing the time series length, assessing whether and to what extent Ultra-Short-Term (UST) analysis is capable of extracting information about cardiovascular variability from very short recordings. In this work, we compare ST and UST measures computed on electrocardiographic R-R intervals and systolic arterial pressure time series obtained at rest and during both post…
Causal and Non-Causal Frequency Domain Assessment of Spontaneous Baroreflex Sensitivity after Myocardial Infarction
2020
Acute myocardial infarction (AMI) is thought to alter the baroreflex control of arterial pressure. We tested this hypothesis investigating the changes of the cardiovascular response after AMI in comparison with young and old healthy controls studied at rest and during head-up tilt, using causal and non-causal frequency domain measures of the baroreflex sensitivity. Our results indicate: (i) the importance of using a causal approach that takes into account not only feedback but also feedforward effects in the study of interactions between the heart period and the arterial pressure; (ii) the compromised capacity of baroreceptors to control SAP fluctuations in post-AMI patients, both at rest a…
Measurements of cardiac Pre-Ejection period using a combo PPG-ECG system
2015
The extraction of biomedical parameters, for early disease detection, is assuming today an ever increasing and fundamental importance. In particular, in the cardiologic field, the preejection period (PEP) is the duration of the iso-volumetric left ventricle contraction until the aortic valve opening. This parameter is a non-constant additive delay, which rapidly changes in response to stress, emotion and physical effort. To estimate this period, several wearable electronics devices have been developed in literature, and among them the Impedance Cardiogram equipment is the most used. However, these systems are often expensive and bulky. In this paper, we propose a cost-effective and easy to …
Circadian variations of ?synaptic? bodies in the pineal glands of Brattleboro rats
1990
The function of the mammalian pineal gland is regulated primarily by the sympathetic system. Arginine-vasopressin (AVP) may also be involved in the regulation of pineal melatonin synthesis under experimental conditions. The present study was conducted in the AVP-deficient rat strain, the Brattleboro rat, to investigate whether the numbers and rhythms of pineal "synaptic" bodies in this strain are different from those found in intact rats. AVP or its non-vasoconstrictive analog, deamino-D-AVP, was also injected intra-arterially in Brattleboro or Sprague-Dawley rats to test whether this procedure influences "synaptic" body numbers. Brattleboro rats were killed at different time-points through…
Simultaneous Hybrid Treatment of Multilevel Peripheral Arterial Disease in Patients with Chronic Limb-Threatening Ischemia
2021
Background: Hybrid treatments (HT) aim to reduce conventional open surgery invasiveness and address multilevel peripheral arterial disease (PAD). Herein, the simultaneous HT treatment in patients with chronic limb-threatening ischemia (CLTI) is reported. Methods: Retrospective analysis, for the period from May 2012 to April 2018, of patients presenting multilevel PAD with CLTI addressed with simultaneous HT. The outcomes of these interventions were measured the following metrics: early technical successes (within 30 days following treatment) and late technical successes (30 days or more following treatment) and included mortality, morbidity symptoms recurrence, and amputation. Survival and …