Search results for " Oxygenation"
showing 10 items of 123 documents
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…
The Use of Mixed Populations of
2017
Saccharomyces cerevisiae is the most widespread microorganism responsible for wine alcoholic fermentation. Nevertheless, the wine industry is currently facing new challenges, some of them associate with climate change, which have a negative effect on ethanol content and wine quality. Numerous and varied strategies have been carried out to overcome these concerns. From a biotechnological point of view, the use of alternative non-Saccharomyces yeasts, yielding lower ethanol concentrations and sometimes giving rise to new and interesting aroma, is one of the trendiest approaches. However, S. cerevisiae usually outcompetes other Saccharomyces species due to its better adaptation to the fermenta…
Tumor hypoxia and therapeutic resistance
2008
For many years, the identification of tumor hypoxia, its systematic characterization and the assessment of its clinical relevance were not possible due to the lack of methods suitable for the routine measurement of intratumoral oxygen tensions in patients. In the late 1980s, a novel and clinically applicable standardized procedure was established enabling the determination of tumor oxygenation in accessible primary tumors, local recurrences, and metastatic lesions in patients using a computerized polarographic needle electrode system (Vaupel et al. 1991; Hockel et al. 1991). Within a relatively short period of time, the significance of tumor oxygenation for therapy outcome became evident in…
Tumor Oxygenation and Its Relevance to Tumor Physiology and Treatment
2003
For many years, the identification of tumor hypoxia, its systematic characterization and the assessment of its clinical relevance were not possible due to lack of methods suitable for the routine measurement of intratumoral oxygen tensions in patients. In the late 1980s, a novel and clinically applicable standardized procedure was established enabling the determination of the tissue oxygenation status in primary tumors, local recurrences, and metastatic lesions in patients using a computerized polarographic needle electrode system. Within a relatively short period of time, the significance of tumor oxygenation for therapy outcome became evident in numerous experimental and clinical studies.
Impact of Various Thermal Doses on the Oxygenation and Blood Flow in Malignant Tumors Upon Localized Hyperthermia
1984
Hyperthermia exhibits various direct cytocidal effects (Dickson, 1977; Overgaard, 1977; Suit, 1977). During heat treatment in vivo, several indirect mechanisms enhance the direct cell-killing capacity of hyperthermia. Therefore, the effective use of hyperthermia can overcome some of the well-known problems involved in modern radiation therapy at least in some malignant tumors.
Nitrogen isotope evidence for stepwise oxygenation of the ocean during the Great Oxidation Event
2019
24 pages; International audience; The Earth’s oxygenation represents one of the most important environmental drivers of life’s evolution, with the first rise, known as ‘the Great Oxidation Event’ (GOE), corresponding to unpreceded accumulation of atmospheric O2, changes in the flux of marine nutrients and possibly global glaciations. However, the detailed evolution of the GOE is still debated, as for instance the accumulation trends of oceanic versus atmospheric oxygen and the nature of biogeochemical responses to oxygenation. Here, we combine organic carbon and bulk nitrogen isotope compositions with major element concentrations and iron speciation data of sedimentary rocks recovered from …
Current Status of Knowledge and Critical Issues in Tumor Oxygenation
1998
In 1972 we started the systematic investigation of oxygenation status in (a) experimental tumor systems in rats and mice [e.g., 1–6], (b) in human tumors xenotransplanted into immune-deficient rnu/rnu-rats [e.g., 7–9], (c) in tumors derived from spontaneously tumorigenic or ras-transformed cell lines [10], and (d) in human tumors in situ [e.g., 11–15] under various pathophysiological conditions using polarographic O2 needle electrodes. In the earlier studies a cryospectrophotometric ex vivomicrotechnique was also used that allowed the measurement of HbO2 saturation in individual red blood cells in tumor microvessels [e.g., 16, 17]. Besides polarographic and cryospectrophotometric microtechn…
Tumor Vascularity, Hypoxia, and Malignant Progression in Solid Neoplasms
1998
Malignant progression designates the biologic process which transforms a phenotypically normal cell fixed and cooperating within a tissue into a disseminated therapy-resistant lethal disease. In clinical terms this process consists of three major steps (Fig. 1): () the transition from regulated to deregulated cell proliferation, () the emerging ability of the neoplastic cell collectives to induce angiogenesis and to invade other tissues, () the development of metastases and of resistance towards anti-tumor therapies.
Hyperspectral imaging in perfusion and wound diagnostics – methods and algorithms for the determination of tissue parameters
2018
Abstract Blood perfusion is the supply of tissue with blood, and oxygen is a key factor in the field of minor and major wound healing. Reduced perfusion of a wound bed or transplant often causes various complications. Reliable methods for an objective evaluation of perfusion status are still lacking, and insufficient perfusion may remain undiscovered, resulting in chronic processes and failing transplants. Hyperspectral imaging (HSI) represents a novel method with increasing importance for clinical practice. Therefore, methods, software and algorithms for a new HSI system are presented which can be used to observe tissue oxygenation and other parameters that are of importance in supervising…
Ventilatory chemosensitivity, cerebral and muscle oxygenation, and total hemoglobin mass before and after a 72-day mt. Everest expedition.
2014
Abstract. Cheung, Stephen S, Niina E. Mutanen, Heikki M. Karinen, Anne S. Koponen, Heikki Kyro ̈ la ̈ inen, Heikki O. Tikkanen, and Juha E. Peltonen. Ventilatory chemosensitivity, cerebral and muscle oxygenation, and total hemoglobin mass before and after a 72-day Mt. Everest expedition. High Alt Med Biol 15:331–340, 2014.— Background: We investigated the effects of chronic hypobaric hypoxic acclimatization, performed over the course of a 72-day self-supported Everest expedition, on ventilatory chemosensitivity, arterial saturation, and tissue oxygenation adaptation along with total hemoglobin mass (tHb-mass) in nine experienced climbers (age 37 – 6 years, _ VO 2peak 55 – 7mL $ kg - 1 $ min…