Search results for "Tissue oxygenation"
showing 10 items of 16 documents
Stable bioenergetic status despite substantial changes in blood flow and tissue oxygenation in a rat tumour.
1994
Experiments on s.c. rat tumours (DS sarcoma) were performed to determine whether chronic or acute changes in tumour perfusion necessarily lead to changes in tissue oxygenation and bioenergetic status since, as a rule, blood flow is thought to be the ultimate determinant of the tumour bioenergetic status. Based on this study, there is clear experimental evidence that growth-related or acute (following i.v. administration of tumour necrosis factor alpha) decreases in tumour blood flow are accompanied by parallel alterations in tissue oxygenation. In contrast, tumour energy status remains stable as long as flow values do not fall below 0.4-0.5 ml g-1 min-1, and provided that glucose as the mai…
Laser Doppler flux and tissue oxygenation of experimental tumours upon local hyperthermia and/or hyperglycaemia
1992
Laser Doppler fluxmetry and oxygen partial pressure (pO2) histography have been applied to investigate the acute effects of hyperthermia (HT) and/or hyperglycaemia (HG) on microcirculatory function and tissue oxygenation of subcutaneous rat tumours growing on the dorsum of the hind foot. The experiments were performed to test whether, and to what extent, the two adjunct treatment modalities applied alone or in combination can modify these therapeutically relevant parameters. Local HT was performed in a saline bath (44 degrees C) for 2 h; HG was induced by i.v. infusion of 40% glucose solution for 2.5 h (blood glucose levels: 35-40 mM during heating). Laser Doppler flux (LDF) in superficial …
TISSUE OXYGENATION AND NORMAL AND HYPERTHERMIC CONDITIONS
1981
Publisher Summary This chapter describes the tissue oxygenation and normal and hyperthermic conditions. The knowledge of the effect of hyperthermia on tumor and normal tissue blood flow is important not only for the effect of hyperthermia on hypoxic cells at the time of radiation, but also for differential tumor heating. There is considerable evidence from plethsmography that an elevation of normal tissue temperature to 41°C is accompanied by a considerable increase in blood flow. The chapter discusses studies that were conducted to examine changes in the microenvironment of normal and tumor tissue as measured directly with ultramicroelectrodes. In situ studies were carried out in fourth ge…
A significant p value is not equivalent to the superiority of one test index over another
2019
Background In patients with septic shock, the skin is often chosen for the evaluation of peripheral perfusion and oxygenation. Changes in skin microcirculatory vessel oxygen saturation and relative hemoglobin concentration can be described using a mottling score or captured with hyperspectral imaging. However, the effectiveness of the mottling score in assessing microcirculation remains to be shown. We hypothesize that the mottling score in patients with septic shock is related to skin microcirculatory perfusion indices quantified by hyperspectral imaging, biomarkers that reflect endothelium activation and damage, and clinical outcome. Methods Hyperspectral imaging of the knee area was perf…
Epinephrine Versus Norepinephrine for Cardiogenic Shock After Acute Myocardial Infarction
2018
IF 16.834 (2017); International audience; BACKGROUND Vasopressor agents could have certain specific effects in patients with cardiogenic shock (CS) after myocardial infarction, which may influence outcome. Although norepinephrine and epinephrine are currently the most commonly used agents, no randomized trial has compared their effects, and intervention data are lacking. OBJECTIVES The goal of this paper was to compare in a prospective, double-blind, multicenter, randomized study, the efficacy and safety of epinephrine and norepinephrine in patients with CS after acute myocardial infarction. METHODS The primary efficacy outcome was cardiac index evolution, and the primary safety outcome was…
Tissue oxygenation in brain, muscle and fat in a rat model of sleep apnea: differential effect of obstructive apneas and intermittent hypoxia.
2011
Study Objectives: To test the hypotheses that the dynamic changes in brain oxygen partial pressure (PtO 2) in response to obstructive apneas or to intermittent hypoxia differ from those in other organs and that the changes in brain PtO 2 in response to obstructive apneas is a source of oxidative stress. Design: Prospective controlled animal study. Setting: University laboratory. Participants: 98 Sprague-Dawley rats. Interventions: Cerebral cortex, skeletal muscle, or visceral fat tissues were exposed in anesthetized animals subjected to either obstructive apneas or intermittent hypoxia (apneic and hypoxic events of 15 s each and 60 events/h) for 1 h. Measurements and Results: Arterial oxyge…
Oxygen-haemoglobin dissociation curve in hypoxic rats of first or second generation.
1993
SUMMARY 1. Albino Wistar rats were raised in a normobaric hypoxic environment (10% O2 in N2). Two generations of hypoxic rats were observed for changes in their haemoglobin-oxygen (Hb-O2) dissociation curves (ODC), 2,3-diphosphoglycerate (2,3-DPG), haemoglobin (Hb), and Hill coefficients at P50 (n50). The first generation were called (H1) and the second generation (H2). The control group (N) had a normoxic environment. 2. Thirty-five rats (13 N rats, 12 H1 rats and 10 H2 rats) were used. The 2,3-DPG was significantly higher in both hypoxic groups when compared with N rats (2.02 ± 0.51 mmol/L) but 2,3-DPG of H2 rats was significantly lower than that of H1 rats (H1 = 3.48±0.58 mmol/L and H2 =…
Relating Measuring Signals From P O 2 Electrodes to Tissue P O 2: A Theoretical Study
1992
Organ surface P O 2 measurement by oxygen sensitive electrodes has proved to be an efficient tool for monitoring changes in tissue oxygenation status in a number of experimental and clinical situations. A parameter giving more direct information is the P O 2 distribution within tissue cells which, however, can only be assessed by more invasive methods. To date, a quantitative relation between P O 2 electrode measurements and P O 2 in tissue cells has not been established. Part of this problem lies in the fact that any surface electrode P O 2 measurement is not confined to tissue cells but rather represents some average over P O 2 values in a certain volume containing not only tissue cells b…
An Update Review of Saffron and its Active Constituents
1996
This paper reviews the literature on recent research on the chemical composition and pharmacological activities of saffron (Crocus sativus) and its active constituents, mainly as antitumoral, hypolipidemic and tissue oxygenation enhancement agents.
The Effect of Nicotinamide on Microcirculatory Function, Tissue Oxygenation and Bioenergetic Status in Rat Tumors
1994
The failure of many attempts to improve tumor oxygenation - and thus the outcome of standard radiotherapy - may be due to the fact that the occurrence of hypoxia in tumors is not solely a result of diffusion-limited “chronic” hypoxia but is also due to temporary flow cessations in microregional tumor perfusion which have been shown to occur in tumor tissue1. As a result, attempts have more recently been made to reduce hypoxia in tumors through the reduction of tumor perfusion fluctuations. The benzamide analog nicotinamide is an agent which has recently received attention in this respect. It has been reported to be an effective, tumor-specific radiosensitizer in several tumor models, an eff…