Generation of superoxide via the interaction of nitrofurantoin with oxyhemoglobin.

Nitrofurantoin was found to interact with HbO2 to cause the concomitant formation of methemoglobin and superoxide. The rate of formation of methemoglobin and superoxide was linearly dependent upon the concentration of nitrofurantoin and could be inhibited by superoxide dismutase, catalase, or the prior conversion of HbO2 to ethylioscyanoferrohemoglobin. The ability of nitrofurantoin to interact with HbO2 and cause superoxide formation may represent one mechanism by which it produces red cell toxicity and suggests that generation of superoxide in erythrocytes may occur via a different mechanism than that which occurs in microsomes.

A kinetic study on the inhibition of hen brain neurotoxic esterase by mipafox.

A direct method of assaying neurotoxic esterase (NTE) activity, using 4-nitrophenyl valerate, has been described. The technique was used to determine the bimolecular rate (ki), phosphorylation (k2), and affinity (Kd) constants for the reaction of hen brain microsomal NTE with mipafox. Results indicate that the new technique for assaying NTE makes detailed kinetic studies of NTE inhibition possible.

[Cochlear responses to dynamic click pattern in the guinea pig].

Fast cochlear adaptation expressed as the percent of inhibition of the summed action potential, has been studied from the guinea pig cochlear responses to click trains, ramps, and steps in both directions. The transition time function of adaptation to constant click trains does not depend on the click strength, but rather on the click interval. At the background of steady state adaptation, click steps produce only transient changes of the adaptive state, opposite to step direction.

Equipotentiality of function in dichotic listening.

Listeners who had demonstrated right-ear dichotic listening preference in the first of four listening sessions were randomly assigned to an experimental and control group. Both groups participated in three more dichotic listening sessions. For sessions 2 and 3, left-ear responses were reinforced for the experimental group listeners.

Antireflux ureteroileosigmoidostomy by means of ileal intussusception.

Ureteroileosigmoidostomy is recommended for supravesical urinary diversion after cystectomy. Wallace's method for the ileal conduit with a terminal nipple is employed, but the ileal segment is anastomosed to the rectosigmoid instead of the abdominal wall. In this way, the nipple on the distal end of the ileal segment protrudes into the lumen of the large bowel rather than into the abdominal wall, preventing therefore sigmoidoilal reflux.

Outcome of hepatitis in children with acute leukemia.

The cases of 31 children with acute leukemia and concurrent hepatitis were evaluated for the outcome of their hepatitis. Thirteen of these children had hepatitis B and 18 children had a non-B hepatitis. Chronic hepatitis developed in more than half of the children with acute hepatitis, with the majority of cases being of the chronic, active type.

N6-Trimethyl-lysine metabolism. Structural identification of the metabolite 3-hydroxy-N6-trimethyl-lysine.

(1)H and (13)C nuclear-magnetic-resonance spectroscopy and functional-group analysis were used to determine the molecular structure of an isolated metabolite (II(b)) of trimethyl-lysine as 3-hydroxy-N(6)-trimethyl-lysine, an important intermediate in the conversion of trimethyl-lysine into trimethylammoniobutyrate and carnitine [Hoppel, Cox & Novak (1980) Biochem. J.188, 509-519].

N6-Trimethyl-lysine metabolism. 3-Hydroxy-N6-trimethyl-lysine and carnitine biosynthesis.

Rats injected with N6-[Me-3H]trimethyl-lysine excrete in the urine five radioactively labelled metabolites. Two of these identified metabolites are carnitine and 4-trimethylammoniobutyrate. A third metabolite, identified as 5-trimethylammoniopentanoate, is not an intermediate in the biosynthesis of carnitine; the fourth and major metabolite, N2-acetyl-N6-trimethyl-lysine, is not a precursor of carnitine.

Sarcomatous renal tumor of childhood. An electron microscopic study.

A review of 106 cases of Wilms' tumor revealed five examples of a distinctive, monomorphic, sarcomatous renal tumor. Electron microscopic studies suggested that such tumors have their origin from the blastemal cap cells of the developing metanephros. These variants of Wilms' tumor are more likely to metastasize to bone and have a poorer prognosis than the usual type of nephroblastoma.

Gene affecting superoxide dismutase activity linked to the histocompatibility complex in H-2 congenic mice.

The activity of cyanide-sensitive, Cu-Zn superoxide dismutase (SOD) was studied in liver sytosols from H-2 congenic strains of mice. Higher SOD activity was found in livers of mice having H-2b/A.BY, B10, and C3H.