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  • Neuronal necrosis  (4)
  • Mitochondria  (3)
  • Reperfusion  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Effect of transient focal ischemia on blood-brain barrier permeability in the rat: correlation to cell injury (1997)
    Springer
    Acta neuropathologica 94 (1997), S. 158-163 
    Details
    ISSN: 1432-0533
    Keywords: Key words Brain ; Focal ischemia ; Reperfusion ; Albumin extravasation ; Blood-brain barrier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Prolonged ischemia is known to damage the blood-brain barrier, causing an increase in vascular permeability to proteins. We studied the time course of extravasation of endogenous albumin in rats after 1 and 2 h of middle cerebral artery (MCA) occlusion followed by 6, 12, and 24 h of recirculation. In a separate group of rats that had undergone 1 h of MCA occlusion and 6 h of recirculation, influx of [14C]aminoisobutyric acid (AIB) from blood to brain was also measured. After 1 h of occlusion followed by 6 h of recirculation, neuronal damage was evident in caudoputamen, but there were no signs of blood-brain barrier leakage to either AIB or albumin. At 12 h, the caudoputamen contained extravasated albumin, and at 24 h extravasation was extended to the somatosensory cortex. Animals subjected to 2 h of MCA occlusion showed albumin extravasation in caudoputamen already at 6 h of recirculation, and at 12 and 24 h albumin was abundant in the major part of the right hemisphere. This study suggests that damage to neurons precedes leakage of the blood-brain barrier. Even a relatively short period of ischemia such as 1 h will result in markedly increased vascular permeability. However, a longer transient ischemic insult disrupts the blood-brain barrier earlier than a shorter one.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050688
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  • 2
    Electronic Resource
    Electronic Resource
    The temporal evolution of hypoglycemic brain damage (1985)
    Springer
    Acta neuropathologica 67 (1985), S. 37-50 
    Details
    ISSN: 1432-0533
    Keywords: Hypoglycemia ; Cerebral damage ; Dark neurons ; Neuronal necrosis ; Caudate ; Putamen ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The caudate nucleus and putamen belong to the selectively vulnerable brain regions which incur neuronal damage in clinical and experimental settings of both hypoglycemia and ischemia. We have previously documented the density and distribution of the hypoglycemic damage in rat caudoputamen, but the evolution of the injury, i.e., the sequence of structural changes, has not been assessed. Therefore, in the present study we analyze the light and electron microscopic alterations in the caudoputamen of rats exposed to standardized, pure insults of severe hypoglycemia with isoelectric EEG for 10–60 min, or in rats which, following insults of 30 or 60 min, were allowed to recover for periods from 5 min to 6 months. The hypoglycemic insult produced severe nerve cell injury in the dorsolateral caudoputamen. Immediately after the insult abnormal light neurons with clearing of the peripheral cytoplasm were present. These cells disappeared early in the receovery period, as they do in the cerebral cortex. Dark neurons were also present, but unlike those in the cerebral cortex they did not appear until recovery was instituted. Their number increased for a couple of hours and they became acidophilic within 4–6 h. At this stage, electron microscopy revealed severe clumping of the nuclear chromatin and cytoplasm as well as incipient fragmentation of cell membranes, all these changes indicating an irreversible injury. Within 24 h flocculent densities appeared in the mitochondria and by day 2–3 of recovery the great majority of the medium-sized neurons had undergone karyorrhexis and cytorrhexis, their remnants being subsequently removed by macrophages. After some weeks only large and a few medium-sized neurons remained amidst reactive astrocytes and numerous macrophages. The delay in the appearance of dark, lethally injured medium-sized neurons until the recovery was instituted suggests an effect that does not become apparent until the substrate supply and energy production are restored. Furthermore, it pointt out again the selectivity of the hypoglycemic nerve cell injury with respect to the type (metabolic characteristics?) and topographic location of the neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688122
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  • 3
    Electronic Resource
    Electronic Resource
    The distribution of hypoglycemic brain damage (1984)
    Springer
    Acta neuropathologica 64 (1984), S. 177-191 
    Details
    ISSN: 1432-0533
    Keywords: Hypoglycemia ; Cerebral damage ; Cerebrospinal fluid ; Interstitial fluid ; Neuronal necrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Rats were exposed to insulin-induced hypoglycemia resulting in periods of cerebral isoelectricity ranging from 10 to 60 min. After recovery with glucose, they were allowed to wake up and survive for 1 week. Control rats were recovered at the stage of EEG slowing. After sub-serial sectioning, the number and distribution of dying neurons was assessed in each brain region. Acid fuchsin was found to stain moribund neurons a brilliant red. Brains from control rats showed no dying neurons. From 10 to 60 min of cerebral isoelectricity, the number of dying neurons per brain correlated positively with the number of minutes of cerebral isoelectricity up to the maximum examined period of 60 min. Neuronal necrosis was found in the major brain regions vulnerable to several different insults. However, within each region the damage was not distributed as observed in ischemia. A superficial to deep gradient in the density of neuronal necrosis was seen in the cerebral cortex. More severe damage revealed a gradient in relation to the subjacent white matter as well. The caudatoputamen was involved more heavily near the white matter, and in more severely affected animals near the angle of the lateral ventricle. The hippocampus showed dense neuronal necrosis at the crest of the dentate gyrus and a gradient of increasing selective neuronal necrosis medially in CA1. The CA3 zone, while relatively resistant, showed neuronal necrosis in relation to the lateral ventricle in animals with hydrocephalus. Sharp demarcations between normal and damaged neuropil were found in the hippocampus. The periventricular amygdaloid nuclei showed damage closest to the lateral ventricles. The cerebellum was affected first near the foramina of Luschka, with damage occurring over the hemispheres in more severely affected animals. Purkinje cells were affected first, but basket cells were damaged as well. Rare necrotic neurons were seen in brain stem nuclei. The spinal cord showed necrosis of neurons in all areas of the gray matter. Infarction was not seen in this study. The possibility is discussed that a neurotoxic substance borne in the tissue fluid and cerebrospinal fluid (CSF) contributes to the pathogenesis of neuronal necrosis in hypoglycemic brain damage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688108
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  • 4
    Electronic Resource
    Electronic Resource
    The density and distribution of ischemic brain injury in the rat following 2–10 min of forebrain ischemia (1984)
    Springer
    Acta neuropathologica 64 (1984), S. 319-332 
    Details
    ISSN: 1432-0533
    Keywords: Cerebral ischemia ; Selective vulnerability ; Neuronal necrosis ; Cell death ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The density and distribution of brain damage after 2–10 min of cerebral ischemia was studied in the rat. Ischemia was produced by a combination of carotid clamping and hypotension, followed by 1 week recovery. The brains were perfusion-fixed with formaldehyde, embedded in paraffin, subserially sectioned, and stained with acid fuchsin/cresyl violet. The number of necrotic neurons in the cerebral cortex, hippocampus, and caudate nucleus was assessed by direct visual counting. Somewhat unexpectedly, mild brain damage was observed in some animals already after 2 min, and more consistently after 4 min of ischemia. This damage affected CA4 and CA1 pyramids in the hippocampus, and neurons in the subiculum. Necrosis of neocortical cells began to appear after 4 min and CA3 hippocampal damage after 6 min of ischemia, while neurons in the caudoputamen were affected first after 8–10 min. Selective neuronal necrosis of the cerebral cortex worsened into infarction after higher doses of insult. Damage was worst over the superolateral convexity of the hemisphere, in the middle laminae of the cerebral cortex. The caudate nucleus showed geographically demarcated zones of selective neuronal necrosis, damage to neurons in the dorsolateral portion showing an all-or-none pattern. Other structures involved included the amygdaloid, the thalamic reticular nucleus, the septal nuclei, the pars reticularis of the substantia nigra, and the cerebellar vermis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690397
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  • 5
    Electronic Resource
    Electronic Resource
    The temporal evolution of hypoglycemic brain damage (1985)
    Springer
    Acta neuropathologica 67 (1985), S. 13-24 
    Details
    ISSN: 1432-0533
    Keywords: Hypoglycemia ; Cerebral cortex ; Nerve cell injury ; Dark neurons ; Acidophilic neurons ; Mitochondria ; Golgi apparatus ; Cell necrosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the course of a study on the pathogenesis of neuronal necrosis in severe hypoglycemia, the morphological characteristics reflecting reversible and irreversible neuronal lesions were examined as a function of time following normalization of blood glucose. To that end, closely spaced time intervals were studied in the rat cerebral cortex before, during, and up to 1 year after standardized pure hypoglycemic insults of 30 and 60 min of cerebral isoelectricity. Both the superficial and deep layers of the cerebral cortex showed dark and light neurons during and several hours after the insult. By electron microscopy (EM) the dark neurons were characterized by marked condensation of both karyoplasma and cytoplasm, with discernible, tightly packed cytoplasmic organelles. The light neurons displayed clustering of normal organelles around the nucleus with clearing of the peripheral cytoplasm. Some cells, both dark neurons and neurons of normal electron density, contained swollen mitochondrial with fractured cristae. Light neurons disappeared from the cerebral cortex by 4 h of recovery. Some dark neurons in the superficial cortex and almost all in the deep cortex evolved through transitional forms into normal neurons by 6 h recovery. Another portion of the dark neurons in the superficial cortex became acidophilic between 4 and 12 h, and by EM they demonstrated karyorrhexis with stippled electron-dense chromatin. The plasma membrane was disrupted, the cytoplasm was composed of amorphous granular debris, and the mitochondria contained flocculent densities. These definitive indices of irreversible neuronal damage were seen as early as 4–8 h recovery. Subsequently, the acidophilic neurons were removed from the tissue, and gliosis ensued. Thus, even markedly hyperchromatic “dark” neurons are compatible with survival of the cell, as are neurons with conspicuous mitochondrial swelling. Definite nerve cell death is verified as the appearance of acidophilic neurons at which stage extensive damage to mitochondria is already seen in the form of flocculent densities, and cell membranes are ruptured. Our previous results have shown that hypoglycemic neocortical damage affects the superficial laminae, chiefly layer 2. The present results demonstrate that, following the primary insult, this damage evolves relatively rapidly within the first 4–12 h. We have obtained no evidence that additional necrotic neurons are recruited after longer recovery periods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688120
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  • 6
    Electronic Resource
    Electronic Resource
    The temporal evolution of hypoglycemic brain damage (1985)
    Springer
    Acta neuropathologica 67 (1985), S. 25-36 
    Details
    ISSN: 1432-0533
    Keywords: Hypoglycemia ; Hippocampus ; Neuronal necrosis ; Mitochondria ; Astrocyte ; Endothelial microvilli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Part I of this paper has documented the evolution of dark neurons into acidophilic neurons in the superficial laminae as well as the reversion of dark neurons to normal neurons in the deep laminae of the cerebral cortex in hypoglycemic brain damage. The present study describes the temporal evolution of hypoglycemic brain damage in the hippocampus. The evolution of dark neurons to acidophilic neurons was confirmed in this brain region. Four additional problems were addressed: Firstly, delayed neuronal death was looked for, and was found to occur in areas of CA1 undergoing mild damage. However, it was not preceded by a morphological free interval, had ultrastructural characteristics distinct from delayed neuronal death in ischemia, and hence should be considered a distinct phenomenon. Secondly, the gradient in the density of neuronal necrosis in the rat hippocampal pyramidal cell band was exploited to test the hypothesis that a more severe insult causes a more rapid evolution of neuronal changes. This was found to be the case, with a temporal spectrum in the timing of neuronal death: Necrosis occurred already after 2 h medially in the sobiculum, and was delayed by up to several weeks laterally in CA1. Thirdly, the almost universal sparing of CA3 pyramidal neurons after 30 min hypoglycemic isoclectricity was exploited to address the question of whether reactive changes, which could with certainty be deemed reversible, occur in CA3. Mitochondrial injury was seen in these cells, and was found to be recoverable. No reactive changes of the type previously described following ischemic insults were observed. Fourthly, the astrocytic and vascular response of the tissue was studied. A sequence of astrocytic changes representing structural and probably metabolic activation of astrocytes was seen, consisting of morphological indices of increased turnover of cellular components. Capillaries demonstrated endothelial pits, vesicles, and prominent microvilli hours to days after recovery. The results demonstrate that, in the hippocampal gyrus as in other brain regions, hypoglycemic brain damage is distinct from ischemic brain damage and likely has a different pathogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688121
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  • 7
    Electronic Resource
    Electronic Resource
    Calcium metabolism of focal and penumbral tissues in rats subjected to transient middle cerebral artery occlusion (1998)
    Springer
    Experimental brain research 120 (1998), S. 503-509 
    Details
    ISSN: 1432-1106
    Keywords: Key words Extracellular calcium concentration ; Total tissue calcium content ; Middle cerebral artery occlusion ; Reperfusion ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The present experiments were undertaken to define changes in tissue calcium metabolism in focal and perifocal (“penumbral”) tissues following 2 h of transient middle cerebral artery occlusion (MCAO) in rats, induced with an intraluminal filament occlusion technique. The extracellular calcium concentration ([Ca2+]e) was measured with ion-selective microelectrodes in neocortical focus and penumbra. For measurement of total tissue calcium content, tissue samples from these areas were collected and analyzed with atomic absorption spectrometry. During MCAO, [Ca2+]e in a neocortical focal area fell from a normal value of about 1.2 mM to values around 0.1 mM, suggesting translocation of virtually all extracellular calcium to intracellular fluids. Recirculation was accompanied by re-extrusion of calcium within 5–7 min; however, [Ca2+]e never returned to normal but stabilized at about 50% of the control value for the first 6 h, and decreased further after 24 h. In penumbral areas, [Ca2+]e showed the expected transient decreases associated with spreading depression-like (or ischemic) depolarization waves. Recirculation was followed by return of [Ca2+]e towards normal values. In the focus, water content increased from about 79% to about 80.4% at the end of the 2-h period of ischemia. After 2 h and 4 h of recirculation, the edema was aggravated (mean values 81.9% and 81.2%, respectively). After 6 h and 24 h, the edema was more pronounced (83.6% and 83.8%, respectively). In the penumbra, no significant edema was observed until 6 h and 24 h of recirculation. The total tissue calcium content in the focus (expressed by unit dry weight) increased at the end of the ischemia period demonstrating calcium translocation from blood to tissue. After 6 h and 24 h, the content increased two- to threefold, compared with control. Changes in the penumbra were qualitatively similar but less pronounced, and a significant increase was not observed until after 6 h of recirculation. The results suggest that 2 h of MCAO leads to a profound perturbation of cell calcium metabolism. In focal areas, cells fail to extrude the calcium that is gradually accumulated during reperfusion and show massive calcium overload after the first 4–6 h of recirculation. Penumbral tissues show a similar increase in calcium concentration after 6 h of recirculation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050424
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  • 8
    Electronic Resource
    Electronic Resource
    Current concepts on reperfusion injury following focal cerebral ischemia (1999)
    Springer
    Intensivmedizin und Notfallmedizin 36 (1999), S. 260-269 
    Details
    ISSN: 1435-1420
    Keywords: Schlüsselwörter Zerebralischämie ; Reperfusionsschädigung ; Mitochondria ; Key words Cerebral ischemia ; Reperfusion injury ; Mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Reperfusion injury has become a scientific problem of increasing importance, in part because of recent developments of thrombolytic therapy. The mechanisms of reperfusion injury following focal cerebral ischemia, however, are not known in detail. Recent studies strongly suggest that reactive oxygen species (ROS) and calcium overload play an important role in reperfusion injury and that pharmacological interventions against calcium- or free radical-mediated damage could extend the therapeutic window in cerebral ischemia/reperfusion. The mediators involved are known to induce a mitochondrial permeability transition (PT) during the reperfusion period, which is associated with uncoupling of mitochondrial respiration, loss of mitochondrial membrane potential, and a burst production of ROS, leading to cellular death. The mitochondrial PT is considered to be a key process in reperfusion injury following cerebral ischemia, as also observed in other organs such as heart and liver. Pharmacological modulation of mitochondrial permeability changes have the potential to reduce tissue damage due to reperfusion.
    Notes: Zusammenfassung Die Reperfusionsschädigung ist ein an Wichtigkeit zunehmendes wissenschaftliches Problem, z. T. wegen der neueren Entwicklungen in der thrombolytischen Therapie. Die Mechanismen der Reperfusionsschädigung nach fokaler Zerebralischämie sind jedoch in Detail unbekannt. Neuere Studien deuten stark darauf hin, daß reaktive Sauerstoffspezien (ROS) und Kalziumüberladung eine wichtige Rolle bei der Reperfusionsschädigung spielen, und daß pharmakologische Interventionen gegen eine von Kalzium- oder freien Radikalen vermittelte Schädigung die therapeutische Breite bei der Zerebralischämie/ Reperfusion erweitern könnte. Es ist von den entsprechenden Vermittlern bekannt, daß sie eine mitochondriale Permeabilitätstransition (PT) während der Reperfusionszeit induzieren, und eine explosionsartige Produktion von ROS, welche zum Zelltod führt. Der mitochondrialen PT wird eine Schlüsselrolle bei der Reperfusionsschädigung nach Zerebralischämie zugeschrieben, wie auch in anderen Organen z. B. Herz und Leber beobachtet. Eine pharmakologische Modulation der Veränderung der mitochondrialen Permeabilität hat das Potential, reperfusionsbedingte Gewebeschädigung zu reduzieren.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003900050237
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