Microscope field size and the neuropathologic criteria for Alzheimer's disease

Abstract

Figure. (A) High-signal areas in the parieto-occipital white matter bilaterally on T2-weighted images (arrowheads). (B)Cerebral vasospasm of the posterior cerebral arteries. Peripheral branches of the posterior cerebral artery are irregular (arrows). (C) High-signal areas almost disappeared 4 weeks later.undergoing dialysis, rapid increases in blood pressure, convulsions, and hypertensive encephalopathy have been reported to occur after blood transfusions? or during the administration of recombinant human erythropoietin (~HLIEPO).~.' The rate of increase in the hematocrit in response to rHuEPO is known to be dose-dependent, and patients who have received large doses of rHuEPO with subsequent rapid rise in hematocrit have a greater tendency for seizures and hypertensive encephalopathy. In these cases, there is a relatively rapid increase in the hematocrit before the seizures occur. A rapid rise in the hematocrit results in both increased blood viscosity and a loss of hypoxic vasodilation and thus, a rise in the vascular resistance occurs. These events, along with possibly abnormal cerebral vasculature, may result in hypertensive encephalopathy.In our case, the rate of increase in the hemoglobin concentration (4.0 g/dl per week) and the hematocrit (11% per week) were extremely high. In addition to the blood transfusion, the patient's sustained high erythropoiesis, may have contributed to the rapid increases in the hemoglobin concentration and the hematocrit. It is possible that a rapid increase in the hematocrit induced a condition similar to that recognized in anemic renal patients undergoing dialysis.Cerebral vasoconstriction was another interesting finding in our patient. Since brain-capillary leakage and vascular endothelial damage are considered to be closely related to the pathogenesis of RPLS,' the cerebral vasoconstriction in our case may reflect the effect of cerebral vascular damage. Alternatively, cerebral vasoconstriction itself induces hypoxic changes and exacerbates dysfunction of the blood-brain barrier, endothelial cell damage, and cytotoxic edema. With this background, brain edema, especially vasogenic edema, may easily occur and clinical symptoms may appear when the blood pressure rapidly increases as occurs in RPLS.Rather than being an epiphenomenon of vascular damage, cerebral vasoconstriction may have a pathogenic role in the development of RPLS. References1. Hinchey J, Chaves C, Appignani B, et al. A reversible posterior leukocncephalopathy syndrome. N Engl J Med 1996;334:494-500. 2. Jenner PW, Holland PV. Diagnosis and management of transfusion reactions. In: Petz LD, Swisher SN, Kleinman S, Spence RK, eds. Clinical practice of transfusion medicine. 3rd ed. New York: Churchill Livingstone, 1996:905-929. 3. Brown AL, Tucker B, Baker LRI, Raine AEG. Seizures related to blood transfusion and erythropoietin treatment in patients undergoing dialysis. BMJ 1989;299:1258-1259. 4. Tomson CRV, Venning MC, Ward MK. Blood pressure and erythropoietin. Lancet 1988;2:351. 5. Beccari M. Seizures in dialysis ...

Quantification of regional glial fibrillary acidic protein levels in Alzheimer's disease

“…Lesions including SP, neuritic plaques, and neurofibrillary tangles were counted per mm 2 (17) in five fields selected as having the most lesions for each of the four neocortical areas. Immediately following removal of the brain, tissue was resected (usually from the left hemisphere) for storage at )70°.…”

“…Microscopic sections were examined by one of the three study neuropathologists without knowledge of the clinical findings. Lesions including SP, neuritic plaques, and neurofibrillary tangles were counted per mm 2 (17) in five fields selected as having the most lesions for each of the four neocortical areas. The highest count among the five fields was taken to represent that area.…”

Zinc and copper modulate Alzheimer Aβ levels in human cerebrospinal fluid

“…Counts for NP and NFT were calculated by averaging across the four neocortical or two hippocampal areas. Results were recorded as NP per square millimeter and were truncated at 17/mm 2 [33]. There was no upper limit for NFT counts.…”

The Framingham Brain Donation Program: Neuropathology Along the Cognitive Continuum

“…Clinical and pathological studies suggest that concomitant vascular disease is common and determines the time of onset of clinical symptoms in persons with Alzheimer's disease pathology [62-66]. Such overlapping pathology is also likely in persons with MCI.…”