The site of embolization related to infarct size, oedema and clinical outcome in a rat stroke model - further translational stroke research

<p>Abstract</p> <p>Background and purpose</p> <p>Reliable models are essential for translational stroke research to study the pathophysiology of ischaemic stroke in an effort to find therapies that may ultimately reduce oedema, infarction and mortality in the clinic. The purpose of this study was to investigate the relation between the site of arterial embolization and the subsequent oedema, infarction and clinical outcome in a rat embolic stroke model.</p> <p>Methods</p> <p>Thirty-six male Sprague-Dawley rats were thromboembolized into the internal carotid artery. The site of occlusion was demonstrated by arteriography. Following histological preparation and evaluation, the size of the hemispheres and the infarcts were measured by quantitative histology and planimetry. Another parallel stroke model study was subsequently examined to investigate if the conclusions from the first study could be applied to the second study.</p> <p>Results</p> <p>The median size of the infarct was 40% of the ipsilateral hemisphere in both the 19 animals with occlusion localised to the intracranial part of the internal carotid artery and in the 11 animals where the main trunk of the middle cerebral artery was occluded. In 5 animals, occlusion of the extracranial part of the internal carotid artery resulted in significantly smaller infarcts compared to other groups (p < 0.01). Another independent study re-confirmed these results. Furthermore, significant correlations (R > 0.76, p < 0.0001) were found between 1) cortical, subcortical, and total infarct volumes, 2) oedema in percent of the left hemisphere, 3) clinical score before termination and 4) postoperative weight loss.</p> <p>Conclusions</p> <p>Distal occlusions of the intracranial part of the internal carotid or middle cerebral arteries resulted in comparable large sized infarctions and oedema. This indicates that investigators do not need a similar number of such occlusions in each experimental group. Contrary to observations in the clinic, distal internal carotid artery occlusions did not result in worse outcome than middle cerebral stem occlusions, but this finding may be explained by the controlled emboli size in this experimental stroke model.</p

Technical and Comparative Aspects of Brain Glycogen Metabolism.

It has been known for over 50 years that brain has significant glycogen stores, but the physiological function of this energy reserve remains uncertain. This uncertainty stems in part from several technical challenges inherent in the study of brain glycogen metabolism, and may also stem from some conceptual limitations. Factors presenting technical challenges include low glycogen content in brain, non-homogenous labeling of glycogen by radiotracers, rapid glycogenolysis during postmortem tissue handling, and effects of the stress response on brain glycogen turnover. Here, we briefly review aspects of glycogen structure and metabolism that bear on these technical challenges, and discuss ways these can be overcome. We also highlight physiological aspects of glycogen metabolism that limit the conditions under which glycogen metabolism can be useful or advantageous over glucose metabolism. Comparisons with glycogen metabolism in skeletal muscle provide an additional perspective on potential functions of glycogen in brain

Degenerative Veränderungen im alternden Innenohr, mit besonderer Berücksichtigung der vasculären Veränderungen, in Flächenpräparaten der menschlichen Cochlea dargestellt

Temporal bones from 150 patients, ranging in age from fetuses and newborn to 97 years, were studied by the technique of microdissection and the use of surface specimens stained with OSO 4 . Hair cell and nerve degeneration were seen in the extreme basal turn of the cochlea even in children. In the fetal cochlea vascularization is very dense, in the newborn and infant somewhat less so. A gradual involution of blood vessels occurs postnatally and continues with maturity and aging. Involution is seen especially in the membranous wall of the cochlea and in the system of spiral vessels of the basilar membrane and vestibular lip. During the first decade the radiating arterioles and the outer spiral vessel in the basal turn are reduced to their adult size. In presbycusis material we observed a marked loss of capillaries and of some of the radiating arterioles in the spiral ligament. Other arterioles had thickened walls. This devascularization was accompanied by atrophy and acellularity of the spiral ligament and atrophy of the stria. Atrophy of the spiral vessels was seen, especially in the lower half of the basal turn. Most of the cochlear blood vessels have clearly distinguishable perivascular spaces. Vessels which had become occluded and disappeared left behind them intervascular strands and/or avascular channels . Such channels were seen to connect the perivascular space of one capillary with that of another, representing the perivascular space of the vessel which had atrophied. The hair cell and nerve degeneration seen in presbycusis may be caused, at least in part, by microangiopathy of this type. Similar vascular changes have been observed in retinal vessels. It is possible that the gradual reduction of blood supply through the disappearance of capillaries occurs in many tissues of the body and plays an important role in the aging process. Mit Hilfe der Oberflächenpräparation wurden von uns 150 menschliche Labyrinthe aller Altersgruppen untersucht. Es wurde eine Haarzellen-und Nervendegeneration schon im Kindesalter beobachtet. Blutgefäße in der Schnecke haben perivasculdre Spalten; Gefäße atrophieren and werden zu „avascular channels”, leeren Spaltrdumen oder Striingen. Bei Presbyakusis fällt neben der Haarzell- and Nervendegeneration in der Basalwindung der Schnecke die Gefäßatrophie im Ligamentum spirale und der Membrana basilaris auf. Dazu kommt noch eine beträchtliche Atrophie des Ligamentum spirale und der Stria vascularis. Bemerkenswert ist, daß die Devascularisation schon im Kindesalter beginnt.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47255/1/405_2004_Article_BF00373313.pd