Isolation and partial characterization of an endogenous inhibitor of ceramide glycosyltransferases from rat brain

A heat-stable factor has been extracted from the microsomal membranes of rat brain that inhibits the activities of rat brain ceramide galactosyl- and glucosyltransferases. It is nondialyzable, susceptible to proteolytic enzymes but resistant to DNase and RNase, and has no effect on lysosomal hydrolytic enzymes. The factor could also be prepared from microsomes of bovine, mouse, and rabbit brains and in much lower concentrations, from systemic organs of rats. This inhibitor might play a role in the regulation of ceramide glycosyltransferases in vivo.     

Determination of manganese in biological materials by atomic absorption spectroscopy

A method for the measurement of manganese in biological materials using long-path atomic absorption spectroscopy is described. Interference due to anions and cations is eliminated by performing the measurements in threequarter-saturated oxine (8-hydroxyquinoline). It is simple to perform and is sensitive over the range of 0.05–1.0 μg/ml. It does not require prior extraction with organic solvents or the use of the method of additions. The overall precision is excellent. The accuracy has been established using National Burean of Standards certified standards and by comparison with an emission spectrographic method.     

Gelation of Limulus Lysate by Synthetic Dextran Derivatives

The Limulus test has been considered specific for the presence of bacterial endotoxins. To synthesize a simple model of endotoxin, palmitoyldextran phosphate was prepared by modification of dextran by palmitoylation and phosphorylation. The present studies indicated that a variety of polysaccharide derivatives, such as palmitoyldextran phosphate, palmitoyldextran, and dextran phosphate, give a positive Limulus test and show pyrogenic activity, except for low molecular dextran derivatives. On the other hand, polysaccharides, such as dextran, starch (soluble), chitosan, xylan, and lentinan, were negative in these assays. The gelation reaction of Limulus lysate by modified dextran derivatives may depend on the molecular weight or modification of polysaccharides by palmitoylation and/or phosphorylation to a great extent.     

Extramedullary plasmacytoma of the thyroid gland producing gamma heavy chain

We encountered a 65-year-old man with gamma heavy chain disease associated with extramedullary plasmacytoma of the thyroid gland. Serum electrophoresis revealed an abnormal fast gamma band that cross-reacted with anti-IgG (Fc gamma) sera immunoelectrophoretically. Intracytoplasmic monoclonal immunoglobulin, IgG (Fc gamma), was demonstrated in thyroid tissue sections using an indirect immunofluorescence method. After surgery, the serum abnormal fast gamma band disappeared. At the time of writing, the patient has survived 18 months post-surgery.