We studied the topographic distribution of Alzheimer's disease (AD)-type pathologic changes in the brains of 25 presumed nondemented elderly individuals. Neurofibrillary tangles (NFT) and senile plaques (SP) were evaluated quantitatively in nine to 20 cytoarchitectural fields using thioflavine S, Alz-50, and anti-beta/A4 amyloid immunohistochemistry. Our observations suggest that (1) most individuals over the age of 55 have at least a few NFT and SP; (2) the topographic distribution of NFT and SP in nondemented elderly individuals follows a consistent pattern of vulnerability in different cytoarchitectural areas; (3) NFT occur most frequently in the entorhinal and perirhinal cortices and the CA1/subiculum field of the hippocampus, while neocortical areas are less frequently affected; (4) immunohistochemically defined subtypes of SP have distinct patterns of distribution. beta/A4 immunoreactive SP are present in neocortical areas much greater than limbic areas. Alz-50 immunoreactive SP are infrequent and limited to those areas that contain Alz-50-positive neurons and NFT. These patterns closely match the hierarchical topographic distribution of NFT and SP observed in AD, suggesting a commonality in the pathologic processes that lead to NFT and SP in both aging and AD.

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SUMMARY In a group of forty cases of cysticercosis of the central nervous system, 59% presented with intracranial hypertension due to obstructive hydrocephalus. Ventricular or cistemal cysts, and chronic cysticercus meningitis were the most common causes of hydrocephalus. Seizures occurred in 40% of the patients, in one-half of them in association with CT-detected parenchymatous cysts. In 20% of the cases progressive mental deterioration was the main clinical feature, at times associated with hydrocephalus. CT scan provided the highest diagnostic yield, being abnormal in 90% of cases. Long term prognosis was poor, with a mortality rate of 38% over a 40-month follow-up period. The most common cause of death (60%) was meningitis. CSF shunting is the treatment of choice for hydrocephalus, irrespective of its mechanism. Surgical resection is indicated in some cases with a single superficial (cortical) or posterior fossa cyst. Supratentorial cysts carry a relatively benign prognosis.The aetiology of neurocysticercosis, the biological cycle of the parasite, and the pathological lesions it provokes have been well documented.'-'°However, some aspects of the disease, such as its initial clinical manifestations, the yield of various diagnostic methods, and its treatment still remain unclear. In addition, accurate figures on outcome and long-term prognosis are not widely available. We report a group of 40 patients with cysticercosis of the central nervous system, in an attempt to clarify these questions.Forty patients with a diagnosis of neurocysticercosis were studied. Aids to diagnosis included complement fixation reaction in blood and cerebrospinal fluid (CSF), counterimmunoelectrophoresis, and intradermal reactions. These tests were positive in 32 cases. The diagnosis was verified pathologically in 18 cases, and the cause of death was verified by necropsy in 10 cases. Follow-up covered periods from 7 to 97 months (mean: 40 months) in 32 patients.

Postmortem examination of a 65-year-old anosmic woman revealed rudimentary olfactory bulbs, an imperforate cribriform plate, and sulcal abnormalities of the orbitofrontal surface of the brain. The remainder of the brain, skull, and body was normal. This abnormality most likely resulted from a local insult to the area of the cribriform plate during early fetal life, occurring after the induction of olfactory bulb differentiation, but before migration and complete differentiation of the olfactory bulbs. Such a lesion can be dated to approximately 11 to 12 weeks gestational age. The malformation may represent another variant in the arhinencephaly spectrum, but is termed "olfactory dysgenesis" or "olfactory hypoplasia" to separate it from true olfactory aplasia and arhinencephaly.