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CT and MR imaging techniques are frequently used for the diagnosis and progress monitoring of ischemic stroke in clinical practice and research. After stroke, both methods are characterized by a transient pseudo-normalized imaging signal, the so-called fogging phenomenon. This study evaluates potential pathophysiological changes associated with fogging, as well as its influence on the correct determination of the ischemic lesion in a rat stroke model. Male spontaneously hypertensive rats were subjected to permanent middle cerebral artery occlusion. Ischemic lesion volume, brain edema and grey scale value spread within the ischemic lesion were determined on T2-weighted MR sequences at days 1, 4, 8, 11 and 29 after stroke onset, and compared with immunohistochemistry for astrogliosis, microglia/macrophage infiltration and angiogenesis. All animals showed MR fogging at days 4, 8 and 11 after stroke. The transient normalization of T2 signals occurred independently from the development of infarct volumes, but coincided well with the spatio-temporal occurrence of necrosis, angiogenesis and microglia/macrophage infiltration. Our results suggest that the fogging effect reflects the clearance of necrotic tissue within the ischemic lesion and is thus not relevant for the determination of the lesion volume.
Isotachophoresis using coupled capillaries (ITP) and ion chromatography (IC) – two analytical procedures for the determination of anions in atmospheric wet deposition – were compared. Both techniques were used for the determination of anions in small volume samples of dew, rime and fog deposition. IC was characterized by lower limits of detection and quantitation. The wide dynamic range of the technique made it suitable for accurate and precise determination of the analytes in samples of widely different matrices and analyte levels. No significant differences were observed between the two techniques in terms of time- and labor intensity.
Relatively little is known about the direct influence of acid rain (AR) on pro-and antioxidative changes in plant cells. Intercompartmental differences between cytosol and mitochondria were not studied before. Aboveground parts of plants treated with different pH variants of AR and prooxidative changes (lipid peroxidation) as well as antioxidative enzyme activities (ascorbate peroxidase, APx; glutathione peroxidase, GSH-Px) in the cytosolic and mitochondrial fractions were examined. The character of changes in antioxidative enzyme activities and of prooxidative alterations was closely connected with the cell com partment as well as with pH and time after treatment. The activity of both APx and GSH-Px increased more intensively in cytosol. Contrastingly, strong induction of lipid peroxides formation was observed in the mitochondrial fraction. The results suggest that cucumber mitochondria are more susceptible to oxidative damage caused by AR than cytosol. Antioxidative defense of cytosol appeared to provide sufficient protection against the oxidative stress imposed by AR.
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Klimat Polesia Lubelskiego i jego zmiany

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