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EN
The aim of the study was to analyze changes in tissue oxygen distribution resulting from temperature changes by the use of the Krogh cylinder model with Michaelis-Menten kinetics. A Hill model was also used to describe the oxyhemoglobin dissociation curve. In particular, variable values of parameters of dissociation curve and blood velocity in capillary were considered. Mathematical description was based on two separate equations for radial and axial directions. An additional task related to determination of the temperature, tissue thermal damage and perfusion was also solved. At the stage of numerical realization, the finite difference method was used.
PL
W pracy opisano 4 nieszczęśliwe wypadki wywołane różnicą ciśnienia wewnątrz i na zewnątrz skafandra nurka. Wyjaśniano zagadnienia związane ze ściśnięciem nurka, chorobą kesonową, zbyt szybkim wynurzeniem na powierzchnię a także niedotlenieniem w rezultacie wyczerpania się tlenu w aparacie nurkowym. Analizowano przy tym mechanizm urazów u nurków i zasugerowano metody profilaktyki tych nieszczęśliwych wypadków.
EN
This paper describes 4 unfortunate accidents caused by the difference in pressure inside and outside the diver's suit. The issues relate to diver crushing, caisson disease, too fast an ascent to the surface and hypoxia as a result of exhaustion of oxygen in the diving apparatus are explained. The mechanism of the diving injuries was analysed and methods of prevention of such incidents were suggested.
EN
An attempt is made to use long-term (1979-2014) macrobenthos data series to derive insights on changes in abiotic conditions and on potential effects of long-term macrobenthos variability on food availability for fish and wintering waterfowl. The data were collected from a small embayment, protected as a NATURA 2000 area, functioning as a fishing ground important for the local community and as a site of diverse commercial developments. The analysis showed a drastic reduction of the macrobenthos abundance and biomass, which could have been related to oxygen deficiency; on the other hand, recolonisation processes have also been observed.
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EN
In vitro ischemia models are designed to study various aspects of hypo-perfusion, focusing on the consequences of acute events under body temperature. Cold ischemia is less investigated even though the beneficial effects of cooling is expected. The aim of the present work was to develop a device modeling cold and warm ischemia in vitro. Oxygen-glucose deprivation was applied with continuous nitrogen flow and glucose-free cell culture media to mimic ischemia. The temperature in both chambers were independently set between 4 and 37 °C. Samples were placed inside for the ischemic period, followed by a reperfusion stage under standard cell culture conditions. We tested rat calvaria bone pieces undergoing 1, 7, 12 and 24 h of ischemia at 4 and 37 °C. After 24 h of reperfusion, cell number was measured with a tetrazolium cell viability assay. One hour of warm ischemia paradoxically increased the post-reperfusion cell count, while cold-ischemia had an opposite effect. After 7 h of warm ischemia the cells were already unable to recover, while under cold ischemia 60% of the cells were still functioning. After 12 h of cold ischemia 50% of the cells were still be able to recover, while at 24 h even the low temperature was unable to keep the cells alive. The markedly different effect of warm and cold ischemia suggests that this newly designed systemis capable of reliable and reproducible modeling of ischemic conditions. Moreover, it also enables deeper investigations in the pathophysiology of cold ischemia at cellular and tissue level.
PL
Zaburzona równowaga pomiędzy proliferacją a dojrzewaniem i różnicowaniem komórek nowotworowych powoduje szybki wzrost guza, prowadząc do zwiększenia zapotrzebowania na składniki odżywcze, m.in. glukozę i tlen. Pierwszą odpowiedzią komórek nowotworowych na niewystarczającą ilość składników odżywczych jest zmiana metabolizmu na beztlenowy (efekt Warburga). Glukoza niezbędna do przeprowadzenia tego procesu dostarczana jest za pomocą transporterów – najczęściej białek GLUT1 i SGLT1. Zmiana poziomu i wzoru ekspresji transporterów glukozy w komórkach nowotworowych w porównaniu z komórkami odpowiednich tkanek prawidłowych świadczy o adaptacji, do której doszło w obrębie guza. Dotychczasowe badania pozwoliły ustalić, w których rodzajach nowotworów dochodzi do zmian w ekspresji białek GLUT1 i SGLT1 oraz pokazały, że zmiany te mogą mieć bezpośredni związek z zaawansowaniem choroby i rokowaniem dla pacjentów. Niniejsza praca ma charakter przeglądowy i stanowi zestawienie zmian w poziomie ekspresji transporterów glukozy w niektórych typach nowotworów. Określenie poziomu ekspresji tych białek w komórkach nowotworowych może mieć kluczowe znaczenie dla spersonalizowanej terapii przeciwnowotworowej.
EN
Due to imbalance between proliferation, differentiation and maturation, cancer cells grow rapidly and require elevated levels of oxygen and glucose. The main strategy of cancer cells is to prevent starvation is the anaerobic adaptation of cellular metabolism known as the Warburg’s effect. Increased glucose uptake is maintained by alterating the level and the pattern of glucose transporters expression, mainly GLUT1 and SGLT1. In many cancer types, these proteins are present despite their absence in healthy tissue. Previous researches revealed cancer types in which GLUT1 and SGLT1 expression are altered. There is a strong direct correlation between their expression pattern, cancer stage and prognosis for the patient. This review provides an overview of changes in the level of glucose transporters expression in some cancer types. Determination of glucose transporters expression levels in cancer cells could be crucial for personalized cancer treatment.
EN
Experimental studies of intact sediment cores from the Gulf of Riga, Baltic Sea, were conducted to estimate the response of sediment nutrient fluxes to various near-bottom water oxygen conditions. The experiment was performed in the laboratory using a batch-mode assay type system on the sediment cores held at 4°C and oxygen concentrations maintained at 1, 2, 3, 4 and 5 mg l-1. The results from the experiment were subsequently used to optimise the fit of the sediment denitrification sub-model of the Gulf of Riga basin. Sediment-water fluxes of phosphate were low and directed out of the sediments under all treatments, demonstrating a general decreasing tendency with increasing near-bottom water oxygen concentration. The sediment-water fluxes of ammonium and nitrate+nitrite demonstrated opposing trends: ammonium fluxes decreased whereas nitrate+nitrite fluxes increased with rising near-bottom water oxygen concentration. The modelled fluxes agreed well with the measured ones, with correlation coefficients of 0.75, 0.63 and 0.88 for ammonium, nitrate+nitrite and phosphate fluxes respectively. The denitrification rate in sediments was simulated at oxygen concentrations from -2 to 10 mg l-1. At oxygen concentrations <2 mg l-1 the modelled denitrification was sustained by nitrate transport from water overlying the sediments. With increasing oxygen concentrations the simulated denitrification switched from the process fuelled by nitrates originating from the overlying water (Dw) to one sustained by nitrates originating from the coupled sedimentary nitrification – denitrification (Dn). Dn reached its maximum at an oxygen concentration of 5 mg l-1.
PL
Angiogeneza zwana również neowaskularyzacją jest wieloetapowym procesem tworzenia nowych naczyń krwionośnych w miejscu już istniejących, regulowanym przez czynniki pobudzające (proangiogenne) oraz hamujące (antyangiogenne). Nowotworzenie naczyń zachodzi w procesach fizjologicznych oraz w stanach patologicznych organizmu. W wyniku zaburzenia równowagi między czynnikami proangiogennymi, aktywującymi proces tworzenia nowych naczyń a czynnikami hamującymi (antyangiogennymi) dochodzi do przewagi aktywacji czynników angiogennych oraz nadmiernej angiogenezy, co sprzyja rozwojowi guza nowotworowego. W wyniku niedotlenienia (hipoksji) tkanki dochodzi do aktywacji czynników angiogennych, w tym przede wszystkim czynnika odgrywającego kluczową rolę w progresji nowotworowej – VEGF (ang. Vascular Endothelial Growth Factor). VEGF jest białkiem uważanym za główny czynnik odpowiedzialny za proces angiogenezy oraz wzrost przepuszczalności naczyń krwionośnych; nazywany jest również czynnikiem przepuszczalności naczyniowej. Najważniejszym czynnikiem indukującym proces angiogenezy oraz wydzielanie czynnika VEGF przez komórki nowotworowe jest niedotlenienie (hipoksja) panujące w mikrośrodowisku guza. VEGF jest złym czynnikiem prognostycznym odpowiadającym za progresję oraz aktywację tworzenia przerzutów wielu guzów litych. Zmniejszenie wydzielania czynnika VEGF ma istotne znaczenie w zahamowaniu procesu angiogenezy, a także potencjału metastatycznego komórek nowotworowych, które wcześniej nie uległy zniszczeniu na drodze apoptozy lub nekrozy.
EN
Angiogenesis, also called neovascularization is a multistep process of forming new blood vessels and it is regulated by stimulating factors (proangiogenic) and inhibitors (anti-angiogenenic). Neovascularization occurs in physiological processes and in pathological states of the organism. As a result of an imbalance between proangiogenic factors activating the process of creating new blood vessels and inhibitors (anti-angiogenic) comes to lead the activation of angiogenic factors and excessive angiogenesis, which promotes tumor growth. As a result of hypoxia an activation of tissue angiogenic factors occurs, including, in particular, the key factor in tumor progression - VEGF (Vascular Endothelial Growth Factor). VEGF is a protein considered to be the main factor responsible for process of angiogenesis and an increased vascular permeability’ It is also known as a vascular permeability factor. The most important factor that induces angiogenesis and VEGF secretion by cancer cells is hypoxia in the tumor microenvironment. VEGF is a poor prognostic factor responsible for the progression and metastasis activation of many solid tumors. Decreased levels of VEGF is important in the inhibition of angiogenesis and metastatic potential of tumor cells that have not been destroyed by apoptosis or necrosis.
EN
Benthic fluxes of phosphate and phosphorus distribution in sediments from the southern Baltic Sea were investigated in spring and autumn in 2005 and 2007–2010. Strong spatial variability of phosphate fluxes was observed across the sediment–water interface. The highest values of phosphate flux from sediment (up to 37 μmol m-2 h-1), resulting from the high mineralization rate of organic matter and rapid phosphorus turnover due to macrofaunal activity and hydrodynamic conditions, were observed in the shallow area at depths ranging from 50 to 69 m. The rate of phosphate exchange in the transportation and accumulation bottom area with the water depth .72 m was several times lower (2.12 – 6.22 μmol m-2 h-1). In continuously hypoxic or anoxic sediments, phosphorus was preserved in the refractory organic form, and sediments were depleted of redox-dependent phosphorus forms. In shallow area with well oxygenated near-bottom water, phosphorus was present mainly in the calcium-bound form.
PL
W artykule opisano przypadek nieprawidłowego zachowania nurka pod wodą, które doprowadziło do niedotlenienia i hiperkapni z następową utratą przytomności podczas nurkowania powietrznego, płytkowodnego, w skafandrze suchym, powikłanego urazem ciśnieniowym płuc.
EN
The article discusses the case of an improper diver’s underwater behaviour which led to hypoxia and hypercapnia, with a following loss of consciousness during air diving in shallow water and in a dry diving suit, and consequent pulmonary barotrauma.
EN
The aim of the investigations was to determine the effect of hypoxia and anoxia on the osmoregulation of Corophium volutator. The experiments were performed at salinities of 3.0, 6.6,15.0, and 25.0 PSU in conditions of hypoxia (saturation = 30% O2) and anoxia at a constant temperature of 10°C. Control experiments in aerated water were conducted simultaneously. Hypoxia (saturation = 30% O2) had no statistically significant effect on the osmoregulation of C. volutator after either 6 h or 48 h. However, after 6 h it did lower the osmotic concentration slightly. After 6 h anoxia had no effect on osmoregulation, but no subsequent effects of this factor (after 24 and 48 h) were detectable due to high animal mortality. Anoxia also had no effect on osmoregulation after 24 h at salinities of 15.0 and 25.0 PSU or 48 h at 15.0 PSU.
EN
This study was designed to investigate seasonal and annual changes in the benthic macrofauna in relation to changes in hydrogen sulphide concentration in the sediment and the oxygen content in the water column. Data were collected over a three-year period from 1994 to 1997. The benthic macrofauna inhabiting the sediments of the Gulf of Gdansk, in which H2S is permanently present, consists mostly of species with a high tolerance to oxygen deficiency and the presence of H2S. These species are: Macoma balthica, Harmothoe sarsi, Nereis diversicolor, Saduria entomon and Halicryptus spinulosus, as well as Pontoporeia femorata and Corophium volutator, which are more sensitive to these factors. In 1996-1997 a decline in the abundance of almost all benthic species, and especially of the bivalve M. balthica at all the stations was observed in comparison to 1994-1995.
EN
The repertoires of physiological responses which invertebrates possess play a major role in determining their distribution and survival potential. In the present study the effect of severe hypoxia on the heart rate of S. entomon has been investigated. Saduria entomon are often exposed to extended periods of severe hypoxia and anoxia in their natural habitats. The animals were exposed to conditions of a reduced level of oxygen ( 10% O2 saturation) for 24 hours. The experiment confirms that the pattern of their heart rate changed considerably with time and experimental condition. Under hypoxic condition a steady, regular heart rate was observed and the variability of beat rate decreased in comparison with normoxic one. The mean heart rate of the unburied animals in normoxia was higher than that of the buried S.entomon with considerably lower inter-individual variability. The mean heart rate of animals in hypoxic conditions was similar for all individuals (41.66 ą 2.03 (mean ą SD)), but not significantly different in normoxic conditions (Student t-test, p 0.05).
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