Cerebral grey matter

Blessed G, Tomlinson BE, Roth M The association between quantitative measures of dementia and senile change in the cerebral grey matter of elderly subjects. Br J Psychiatry 144 797-811, 1968... 

Cerebral grey matter i PCr/Pi Migraine, during interictal period 152... 

The density of cerebral capillaries, especially in the cortical grey matter, is very high with mean distances of 40 /xm. The capillary network has a total length of 600-650 km, the mean velocity of the blood flow is below 0.1 cm/s, and the luminal surface extends to 15-30 m2. Thus the blood-brain barrier represents an important surface for potential drug delivery besides gut (30CM100 m2), lung (70-120 m2), or skin (1.8 m2) [24-26, 33-37],... 

The anatomy of the brain and spinal column is very complex. The outer, most visible portion of the brain is known as the cerebrum. The cerebrum accounts for about 80% of the mass of the brain. Covered with a layer of grey matter known as the cerebral cortex, the cerebrum is divided into two hemispheres -left and right. 

Acute cerebral ischemia affects neurons first and the more resistant glia and blood vessels in later stages. Deep cortical layers such as layer III of the cerebral cortex are especially vulnerable, mainly in the parietal and occipital regions and less in the frontal and temporal areas. The more vulnerable neurons are those of the caudate and putamen, the pyramidal cells of Sommer s area and the Purkinje cells in the cerebellum. The thalamus and brainstem are more resistant to hypoxia and ischemia. White matter is generally considered to be more resistant than grey matter. 

A3. Adams, J. E., and Severinghaus, J. W., Oxygen tension on human cerebral grey and white matter. The effect of forced hyperventilation. J. Neurosurg. 19, 959-963 (1962). 

Bone samples for aluminium analysis have been taken from the iliac crest at the time of biopsy or at autopsy (Alfrey et al.. 1976 Maloney et al., 1982) and the specimen placed in an Al-free plastic container. Bone for histological staining is fixed in 10% buffered formalin (Maloney et al., 1982). Crapper et al. (1976) analyzed brain samples from specific areas of the cerebral cortex and from subcortical area. Alfrey et al. (1976) analyzed brain samples from frontal cortex. Whole brain as well as white and grey matter were analyzed. A description of how the specimen was handled before analysis was not provided. Crapper et al. (1976) transported and stored brain samples frozen in Al-free plastic containers and performed dissection from the frozen specimen in a dust-controlled room. All instruments and gloves were rinsed in aluminium-free water. At frequent intervals, this entire procedure was performed on standard homogenized freeze-dried brain powder to ensure little or negligible aluminium contamination. 

In a longterm dosing experiment (1.8% lead acetate in the diet, from 8 days before parturition till 3 months of age), Reyners et al. (1976), showed that the capillaries of the cerebral cortex of dosed neonate rats significantly increased, while the thickness of the cortex reduced progressively. In a later paper these authors reported that the absolute number of cortical capillaries was not modified by lead (Reyners et al., 1979). They concluded that quantitative changes in the vascular supply represented a sequel to a primary effect on grey matter. This is in conflict with the conventional interpretation, i.e. that the neuronal changes observed are the result of a vascular upheaval. 

Cross-sections clearly show that the increase in brain size is entirely due to swelling of the white matter which has a particular mucoid texture and appears confluent with the cerebral grey which is firmer than normal. Located within the white matter are irregularly outlined, edematous areas of cystic degeneration measuring up to 1 cm in diameter and occurring particularly in the deep layers of the frontal and parietal white matter (Aronson and Volk 1962). With duration of the disease over two years the discrepancy becomes more marked... 

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