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  • 1
    Electronic Resource
    Electronic Resource
    The cerebral cortex in congenital hydrocephalus in the H-Tx rat: a quantitative light microscopy study (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 217-224 
    Details
    ISSN: 1432-0533
    Keywords: Hydrocephalus ; Rat ; Cerebral cortex ; Cortical cell density ; Capillary density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Hydrocephalus in the H-Tx rat first develops in late gestation and causes death at 4–7 weeks. The effect of hydrocephalus on overall cortical dimensions and on five specific regions (frontal, sensory-motor, parietal, auditory and visual) has been studied by quantitative light microscopy at 10 and 30 days after birth. The lateral ventricle volumes in hydrocephalic rats were about 40x larger than controls and increased fourfold between 10 and 30 days. Cortical volume was reduced by a small amount at 10 days but was larger in hydrocephalics at 30 days. Thinning of the cortical mantle was severe with disruption of the laminar structure, particularly in the auditory and visual regions, where it was already present at 10 days. The density of cortical cells (neurones and glia) was not altered in hydrocephalics at 10 days but was reduced in all regions at 30 days. Estimates of total cell number suggest that the lower density was not associated with an overall loss of cells. Capillary numerical density was not affected by the hydrocephalus at 10 days after birth but by 30 days it was significantly lower, particularly in the worst-affected posterior regions. The results show that the cerebral cortex is severely distorted and that in advanced hydrocephalus, although overall cell number is not affected, both cell density and capillary density are lower by up to 30%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294448
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  • 2
    Electronic Resource
    Electronic Resource
    CO2 cerebrovascular reactivity as a function of perfusion pressure — a modelling study (1993)
    Springer
    Acta neurochirurgica 121 (1993), S. 159-165 
    Details
    ISSN: 0942-0940
    Keywords: Cerebral blood flow ; autoregulation ; cerebral perfusion pressure ; carbon dioxide ; computer modelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A mathematical model is described that demonstrated the properties of cerebral vascular resistance and compliance expressed as a function of cerebral perfusion pressure (CPP) and arterial CO2 partial pressure (PaCO2). The hypercapnic induced shift of the lower limit of autoregulation to a higher range of CPP, as shown by this model, is a useful characteristic that facilitates the differentiation between normal and impaired autoregulation described previously in experimental studies. Dynamic properties of cerebrovascular circulation derived from the relationship between pulse wave of CBF waveform and CPP have been analysed at different levels of PaCO2-phenomenon, being often described as dependence of blood flow velocity pulsatility index on the autoregulatory reserve. The model was also used to interpret interhemispheric asymmetry of CBF reactivity to changes in arterial concentration of CO2 in patients with carotid artery stenosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01809269
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  • 3
    Electronic Resource
    Electronic Resource
    Metabolite Changes in the Cerebral Cortex of Treated and Untreated Infant Hydrocephalic Rats Studied Using In Vitro 31P-NMR Spectroscopy (1996)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 67 (1996), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The effect of hydrocephalus on cerebral energy metabolites and on intermediates of membrane phospholipid metabolism has been studied in H-Tx rats with inherited infantile hydrocephalus. Hydrocephalic rats and rats with shunts placed at 4–5 days or at 10 days after birth were subjected to magnetic resonance imaging in vivo before 21 days of age to determine the dimensions of the ventricles and cortex. At 21 days, the brains from the three groups of rats, together with age-matched control littermates, were frozen in situ, and chloroform/methanol extracts of cerebral cortex were prepared for high-resolution 31P-NMR spectroscopy. Hydrocephalus resulted in modest decreases in most metabolites quantified. Levels of phosphocreatine, ATP, and diphosphodiesters plus NAD were significantly reduced by 23–32%, and inorganic phosphate content was reduced but not significantly. Levels of the membrane phospholipid intermediates phosphorylethanolamine, glycerophosphorylethanolamine, and glycerophosphorylcholine were also significantly reduced by 30–33%, indicating changes in membrane metabolism. These general decreases are consistent with a loss of cell contents, possibly due to changes in dendrite structure in hydrocephalus. Rats shunt-treated at 4–5 days were similar to control rats for all energy metabolites, but those treated later at 10 days had reduced phosphocreatine and ATP levels. Shunt-treated rats also had reductions in levels of membrane phospholipids, some of which occurred in sham-operated rats. It is concluded that hydrocephalus leads to reductions in levels of energy metabolites and in levels of membrane phospholipids and that the changes in energy metabolites can be reversed by early, but not by later, shunt treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1996.67052030.x
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  • 4
    Electronic Resource
    Electronic Resource
    Neurochemical Changes in the Cerebral Cortex of Treated and Untreated Hydrocephalic Rat Pups Quantified with In Vitro 1H-NMR Spectroscopy (1997)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 68 (1997), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The pathophysiology of infantile hydrocephalus is poorly understood, and shunt treatment does not always lead to a normal neurological outcome. To investigate some of the neurochemical changes in infantile hydrocephalus and the response to shunt treatment, we have used high-resolution 1H-NMR spectroscopy to analyze extracts of cerebral cortex from H-Tx rats, which have inherited hydrocephalus with an onset in late gestation. Hydrocephalic rats and rats with shunts placed at either 4 or 12 days after birth were studied at 21 days after birth, together with age-matched control littermates. In hydrocephalic rats there was a 46–62% reduction in the following compounds: myo-inositol, creatine, choline-containing compounds, N-acetyl aspartate, taurine, glutamine, glutamate, aspartate, and alanine. Phosphocreatine, glycine, GABA, and lactate were also reduced but not significantly. These changes are consistent with neuronal atrophy rather than ischemic damage. In hydrocephalic rats that received shunt treatment at 4 days, there were no significant reductions in any chemicals, indicating a normal complement of neurons. However, some compounds, particularly taurine, were elevated above control. After treatment at 12 days, N-acetyl aspartate and aspartate remained significantly reduced, suggesting continued neuronal deficiency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1997.68010305.x
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  • 5
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    Unknown
    LOCKE'S TRIANGLES (1988)
    Edmonton, Alta. : Periodicals Archive Online (PAO)
    Canadian journal of philosophy. 18:1 (1988:Mar.) 31 
    Details
    ISSN: 0045-5091
    Topics: Philosophy
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:d070-1988-018-01-000003
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  • 6
    Electronic Resource
    Electronic Resource
    Ventricle shunting in young H-Tx rats with inherited congenital hydrocephalus: a quantitative histological study of cortical grey matter (1994)
    Springer
    Child's nervous system 10 (1994), S. 293-301 
    Details
    ISSN: 1433-0350
    Keywords: Ventricle shunting ; Hydrocephalus ; H-Tx rat ; Cerebral cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Shunt surgery is the usual treatment for infantile hydrocephalus, but its precise effects on ventricles and cortex are not well understood. Infant H-Tx rats with inherited hydrocephalus, which have progressive enlargement of the lateral ventricles and thinned cerebral cortex, have been used to study the effect of ventriculosubcutaneous shunts by quantitative light microscopy. Two groups of rats received shunts at mean ages of 7 and 13 days after birth. The brains were processed for wax histology at either 14 or 21 days (n = 3 per group) together with age-matched control and unshunted (hydrocephalic) rats. Ventricle areas were measured and the volume calculated and the cortical layers in five cortical regions were measured. Shungting prevented further expansion of ventricles which were already enlarged at the time of operation, and resulted in volumes which were intermediate between those in control and unshunted rats. Cortical thinning was partially reversed by shunting and the thickness and number of discernible cortical laminae was improved. It is concluded that shunting was largely successful at preventing the pathological effects of hydrocephalus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335166
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