Xanthoma disseminatum of the central nervous system and cranium.

Xanthoma disseminatum is a rare normolipemic histiocytic disorder of non-Langerhans cell origin. It is a chronic systemic disease with a benign course, characterized by disseminated, yellow-orange-colored papules on the face, flexures, and mucosal membranes. We report 3 patients with xanthoma disseminatum, who presented primarily with central nervous system disease and a multitude of imaging findings throughout the craniospinal axis.

Soluble and membrane-bound forms of brain acetylcholinesterase in Alzheimer's disease.

In order to determine the effect of Alzheimer's disease on the relative distribution of soluble and membrane-bound molecular forms of acetylcholinesterase (AChE) in the brain, postmortem samples (delay interval less than 12 h) were obtained from parietal cortex (Brodmann area 40) and hippocampus as well as the areas containing their respective projection nuclei, i.e., substantia innominata and septal nucleus, in 9 patients with Alzheimer's disease (AD) and 4 normal controls. The monomer (G1), dimer (G2), and tetramer (G4) forms of AChE were examined. In AD compared to controls, significant changes occurred in area 40 and hippocampus but not in the areas containing projection nuclei, and included loss of mean total AChE activity, decrease in the relative percentage of membrane-bound G4, and increase in the relative percentage of soluble G1-G2. Percent of soluble G4 was unaffected in AD brain. In area 40 but not hippocampus a large increase in percent membrane-bound G1-G2 occurred. Thus, these results emphasize that the selective decrease in membrane-bound G4 accounts for the decrease in total G4 activity in AD brain.

Testicular changes of acute vitamin A deficiency of cockerels.

Sixty, 1-day-old Arbor Acres broiler cockerels, randomly allotted to three groups, were fed a vitamin A-deficient diet, vitamin A complete diet (control diet), or control diet pair-fed in an amount equal to the quantity consumed by the vitamin A-deficient group. Secondary sex characteristics, as indicated by comb enlargement, developed more rapidly in cockerels consuming the deficient diet. A difference in direct testicular weight was not observed between vitamin A-deficient birds and pair-fed controls, but the testicular weight relative to body weight and the level of testicular maturity were greater in the former. Ultrastructurally, lipid droplets were found in Sertoli cells and germinal epithelium of the deficient birds, but not the pair-fed controls. Paradoxically, serum testosterone concentrations were significantly reduced in sequential serum samples from vitamin A-deficient chicks, but not controls. The evidence indicated that vitamin A deficiency has an androgenic effect in cockerels despite reduced testosterone concentrations.