Epidemiological findings in a brain-tumor cluster in western Missouri.

A cluster of seven primary brain neoplasms was identified in a town of 3000 population during the 10-year period from 1973 to 1982. With six deaths, this represents an age-adjusted mortality rate 4.1 times greater than expected. No other neoplasms were found to be in excess of the anticipated incidence in this town. When brain-tumor mortality rates in 36 other towns of approximately the same population were calculated, only one other town was found to have an excessive rate. All seven tumors in this study were histologically verified: six were diagnosed as glioblastoma multiforme. Interviews were conducted with patients or next-of-kin to obtain the exposure histories of the patients. A number of respondents reported occupational or residential exposure either to a shoe factory or to one of the several chicken hatcheries in the town. Many of the patients ate fish from local ponds that had previously been used as coal mining strip pits. Two patients were siblings. None of the patients had a history of significant head trauma. This unique situation may provide an opportunity to learn more about environmental risk factors for brain neoplasia. Further epidemiological studies are planned.

Intrasellar carotid anastomosis simulating pituitary microadenoma.

Arterial communication between the cavernous segments of the carotid arteries associated with agenesis of the unilateral internal carotid artery is a rare anomaly. Two cases of this anomalous artery with an abnormal sella turcica due to the intrasellar course are reported.

Identification of cells or origin of non-primary afferents to the dorsal column nuclei of the cat.

In order to identify cells of origin in the spinal cord of non-primary afferents to the dorsal column nuclei (DCN), the retrograde transport of horseradish peroxidase (HRP) has been utilized in adult cats. 10 to 30% HRP was injected bilaterally (0.6 mul per side) in the dorsal medulla of nine cats. In most instances the spread of the injected enzyme extended a few millimeters rostrocaudally and infiltrated the DCN as well as other nuclei and fiber tracts. Labelled cells in these cases are numerous in the upper cervical, brachial and lumbosacral cord but are sparse in thoracic segments below T1. At upper cervical levels (C1-C4) HRP-positive neurons are distributed throughout the grey matter but are especially concentrated in the medial part of lamina VI. Cells projecting to the dorsal medulla are mainly localized in lamina IV and, more ventrally, along the medial border of the dorsal horn in the brachial and lumbosacral cord. Labelled cells at these levels are also scattered within lamina I and laminae VI through VII in cases in which the focus of the injection involved extensive portions of the medulla. From cases in which bilateral HRP injections were preceded by spinal tractotomy, it appears that the axons of at least the majority of labelled cells in lamina IV ascend in the ipsilateral dorsal quadrant of the spinal cord. In another group of adult cats, 0.1 to 0.25 mul of 30 to 50% HRP was injected unilaterally in the dorsal medulla at the level of, or rostral to, the obex. With these volumes of exogenous enzyme, an intense reaction product is largely confined within the limits of the DCN. Labelled cells in these cases are found almost exclusively in the medial part of lamina VI at upper cervical levels and, at brachial and lumbosacral levels, throughout lamina IV and medially in lamina V on the side of the cord ipsilateral to the injection. The results are discussed in relation to the organization of the dorsal horn ascending pathways with special reference to cells or origin of the spinocervical tract.