Search results for "oxygenation"
showing 10 items of 237 documents
Endogenous Hypoxia Markers: Case Not Proven!
2008
The pivotal role of hypoxia within the pathophysiological framework of solid malignant tumors is now considered to be indisputable. The fact that hypoxia can cause resistance to various cancer therapies and promote malignant progression is reflected in its adverse impact on prognosis which is repeatedly shown for various tumor entities. Knowledge in this area is based on direct assessment of the oxygenation status using O2-sensitive microsensors. However, weaknesses of this standard method are its invasiveness and limitation to accessible tumor entities. Hypoxia-inducible factor (HIF)-1α, the master transcriptional regulator of the hypoxic response, as well as certain downstream genes, e.g.…
Relationship Between Size and Oxygenation Status of Malignant Tumors
1983
During advanced phases of malignant growth, there are typical changes in the microvasculature pattern within the tissue of many solid tumors. Partly due to these peculiarities of tumor vascularization, a series of characteristic variations of tumor microcirculation occurs (for a review see 1). These alterations lead not only to marked restrictions and inhomogeneities of both convective and diffusive transport but also to an impairment of the efficiency of antitumor therapies.
A maChine and deep Learning Approach to predict pulmoNary hyperteNsIon in newbornS with congenital diaphragmatic Hernia (CLANNISH): Protocol for a re…
2021
Introduction Outcome predictions of patients with congenital diaphragmatic hernia (CDH) still have some limitations in the prenatal estimate of postnatal pulmonary hypertension (PH). We propose applying Machine Learning (ML), and Deep Learning (DL) approaches to fetuses and newborns with CDH to develop forecasting models in prenatal epoch, based on the integrated analysis of clinical data, to provide neonatal PH as the first outcome and, possibly: favorable response to fetal endoscopic tracheal occlusion (FETO), need for Extracorporeal Membrane Oxygenation (ECMO), survival to ECMO, and death. Moreover, we plan to produce a (semi)automatic fetus lung segmentation system in Magnetic Resonanc…
A Bioinspired Approach to Tri-nor-guaianes. Synthesis of (−)-Clavukerin A
2006
A bioinspired approach to tri-nor-guaianes by degradation of the C-7 side chain of related guaia-11-enes is described. In this approach (-)-clavukerin A (1) is obtained by selective ozonolysis-Criegge rearrangement of (+)-1alphaH,7alphaH,10alphaH-guaia-4,11-dien-3-one (4) to afford 7beta-hydroxy and 7beta-acetoxy tri-nor-guaiane derivatives 6 and 7, respectively, which after elimination and deoxygenation give the title compound. The starting guaiadienone is readily obtained from commercially available santonin or (+)-dihydrocarvone.
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.
Odd haemoglobins in odd-toed ungulates: Impact of selected haemoglobin characteristics of the white rhinoceros (Ceratotherium simum) on the monitorin…
2019
Background Due to the current poaching crisis in Africa, increasing numbers of white rhinoceroses (Ceratotherium simum) require opioid immobilisation for medical interventions or management procedures. Alarmingly, the results of both blood gas analysis and pulse oximetry regularly indicate severe hypoxaemia. Yet, the recovery of the animals is uneventful. Thus, neither of the techniques seems to represent the real oxygenation level. We hypothesized that unusual haemoglobin characteristics of this species interfere with the techniques developed and calibrated for the use in human patients. Methods Haemoglobin was isolated from blood samples of four adult, white rhinoceroses. Oxygen dissociat…
Size-Dependent Oxygenation and Energy Status in Multicellular Tumor Spheroids
1990
Multicellular tumor spheroids show numerous analogies to tumor microregions in vivo, such as the development of central necrosis at a certain spheroid size (for reviews see: Mueller-Klieser, 1987; Sutherland, 1988). The histological structure of the cell aggregates suggests that diffusion limitation of oxygen or nutrients in spheroids may cause cell death in the innermost parts of the spheroids. However, measurements with oxygen-sensitive microelectrodes are indicative of necrosis arising in the presence of relatively high oxygen tension (PO2) values, as they were found in normal tissue (Carlsson and Acker, 1985; Mueller-Klieser et al., 1986). Although still controversial in literature, rec…
Systemic PaO2 oscillations cause mild brain injury in a pig model
2016
OBJECTIVE: Systemic PaO2 oscillations occur during cyclic recruitment and derecruitment of atelectasis in acute respiratory failure and might harm brain tissue integrity. DESIGN: Controlled animal study. SETTING: University research laboratory. SUBJECTS: Adult anesthetized pigs. INTERVENTIONS: Pigs were randomized to a control group (anesthesia and extracorporeal circulation for 20 hr with constant PaO2, n = 10) or an oscillation group (anesthesia and extracorporeal circulation for 20 hr with artificial PaO2 oscillations [3 cycles min⁻¹], n = 10). Five additional animals served as native group (n = 5). MEASUREMENTS AND MAIN RESULTS: Outcome following exposure to artificial PaO2 oscillations…
Individualized versus fixed positive end-expiratory pressure for intraoperative mechanical ventilation in obese patients: a secondary analysis
2021
Background General anesthesia may cause atelectasis and deterioration in oxygenation in obese patients. The authors hypothesized that individualized positive end-expiratory pressure (PEEP) improves intraoperative oxygenation and ventilation distribution compared to fixed PEEP. Methods This secondary analysis included all obese patients recruited at University Hospital of Leipzig from the multicenter Protective Intraoperative Ventilation with Higher versus Lower Levels of Positive End-Expiratory Pressure in Obese Patients (PROBESE) trial (n = 42) and likewise all obese patients from a local single-center trial (n = 54). Inclusion criteria for both trials were elective laparoscopic abdominal…
Retrograde in situ versus antegrade pulmonary preservation in clinical lung transplantation: a single-centre experience.
2014
OBJECTIVE Experimental and clinical studies have indicated a beneficial effect of retrograde lung preservation on post-transplant results. Accordingly, we conducted a non-randomized trial. METHODS A total of 209 consecutive recipients transplanted with low-potassium dextrane (LPD)-preserved lungs were eligible for analysis. Antegrade lung preservation (AP) was performed in 173 patients and retrograde in situ perfusion (RP) in 36 patients using low-potassium dextrane solution in all cases. The prostacycline was added to preservation solution. RESULTS The main donor, graft and recipient characteristics did not differ significantly between groups. There was a beneficial trend toward improved o…