Use of a snake venom toxin to characterize the cholinergic receptor protein

alpha-Bungarotoxin, a polypeptide of mol wt 8000 purified from the venom of Bungarus multicinctus, blocks irreversibly and specifically the excitation by cholinergic agonists on the isolated electroplax and on purified membrane fragments in vitro. The toxin also blocks the in vitro binding of decamethonium to a protein recently isolated from electric tissue. This observation strengthens our earlier conclusion that this protein is the cholinergic receptor macromolecule.

Gas Chromatographic Determination of Pyrrolidonecarboxylic Acid

An analytical method is described for analysis of 2-pyrroIidone-5-carboxylic acid (PCA) in foods. PCA was extracted with ethyl acetate, using a modified Widmark extraction apparatus, and then silylated with trimethylchlorosilane and hexamethyldisilazane in the presence of pyridine. The trimethylsilylated PCA derivative was separated by gas-liquid chromatography on a 6′ × 1/4″ °d stainless steel column of 3% SE-30 on Gas Chrom Q and detected with a flame ionization detector. Recovery of PCA was 94-108%. This procedure is a relatively simple and rapid analytical method as compared to the conventional methods.

Fatal primary Epstein-Barr virus infection masquerading as histiocytic medullary reticulosis in young children in Taiwan

We reported 3 fatal cases of primary Epstein-Barr virus (EBV) infection resembling histiocytic medullary reticulosis (HMR) in young children in Taiwan, where an HMR-like illness has been previously found to be prevalent. The disease ran a fulminant course, manifesting as fever, anemia, jaundice, skin rash, pulmonary infiltration, and/or hepatosplenomegaly lasting for only 1-3 weeks. Laboratory tests revealed no hemolytic anemia and Coombs test was negative. Sepsis or HMR was the main clinical differential. At autopsy, the spleen, liver, lymph node, lung, and bone marrow showed infiltration of atypical "histiocytes" or blasts, lymphocytes, and mature histiocytes with hemophagocytosis. Immunophenotype and gene rearrangement studies of the lymphoid tissues revealed that these atypical "histiocytes" were actually polyclonal B immunoblasts in one case and transformed T lymphocytes in the remaining 2 cases, representing two different types of virus-host interaction. Southern blot and in situ hybridization studies on frozen lymphoid tissues demonstrated the presence of EBV DNA in all 3 patients; the study for cytomegalovirus was negative. The young age of these patients, closely correlated with the prevalent age of primary EBV infection in the general populations in Taiwan, strongly suggest that these childhood cases of previously diagnosed HMR-like disease may actually represent a lethal form of primary EBV infection or fatal infectious mononucleosis.