Victor H. Auerbach

Histidinemia. A deficiency in histidase resulting in the urinary excretion of histidine and of imidazolepyruvic acid.

Summary A case of histidinemia is described in which the biochemical abnormality can be attributed to a deficiency of the enzyme histidase. As a result of this deficiency, plasma and urinary levels of histidine are markedly elevated. Imidazolepyruvic, imidazolelactic, and imidazoleacetic acids are excreted in the urine in excessive amounts. The presence of imidazolepyruvic acid in the urine is responsible for a positive test with ferric chloride similar to that due to phenylpyruvic acid found in the urine of patients with phenylketonuria. The possibility of a deficiency of urocanase was ruled out by the demonstration of considerable amounts of formiminoglutamic acid in the urine of the patient following administration of urocanic acid.

Biochemical studies and therapy in subacute necrotizing encephalomyelopathy (Leigh's syndrome)

The clinical course, biochemical abnormalities, and the effects of vitamin therapy in subacute necrotizing encephalomyelopathy are described in a patient who was serially evaluated from birth. Important features include increased cerebrospinal protein, elevated blood lactic acid values, and abnormal macular morphology detected when the patient was asymptomatic. Renal tubular acidosis and alaninemia were noted shortly after the onset of symptoms. No clinical improvement was noted with pharmacologic doses of biotin, thiamine (hydrochloride or propyldisulfide), or lipoic acid. Hepatic pyruvate carboxylase was within the range of control values early in the disease but was negligible in postmortem material. The clinical and biochemical course suggests that low levels of hepatic pyruvate carboxylase in postmortem material were secondary effects of an otherwise as yet unknown biochemical process. Decreased cerebral pyruvate carboxylase activity at autopsy was documented for the first time.

Observations on the coexistence of methylmalonic acidemia and glycinemia

Methylmalonic acidemia and ketotic glycinemia are clinically indistinguishable. Both disorders if untreated are characterized by vomiting, lethargy, failure to thrive, hepatomegaly, ketoacidosis, osteoporosis, neutropenia, and thrombocytopenia. Biochemically, however, they are distinct entities. Glycinemia patients do not excrete methylmalonate, whereas in methylmalonic acidemia massive urinary methylamalonate is an essential finding. Some patients with methylmalonic acidemia are responsive to massive doses of vitamin B 12 .

Protein metabolism in cystic fibrosisof the pancreas

Metabolic balance studies were performed on 5 infants with cystic fibrosis of thepancreas. One of the subjects had hypoproteinemia and intermittent edema. Large quantities of nitrogen were excreted in the stools when the infants received a soybean formula. This was most marked in the hypoproteinemic patient and was considered to be the pathogenetic explanation of his hypoproteinemia. Nitrogen retention was significantly higher when the infants received an evaporated cows milk formula. A paracreatic enzyme preparation led to significant increase in nitrogen retention when added to soybean feedings but not when added to evaporated cows milk feedings. It is recommended that infants with cystic fibrosis of the pancreas should not be fed soybean milk preparations.

The effect of 3-amino-1,2,4-triazole on the synthesis of tryptophan peroxidase-oxidase.

Abstract The administration of 3-amino-1,2,4-triazole to rats inhibited the hepatic porphyrin-containing enzymes tryptophan peroxidase-oxidase and catalase. The effect of 3-amino-1,2,4-triazole on tryptophan peroxidase-oxidase was shown to be due to decreased synthesis of the enzyme and not due to inhibition of a given amount of enzyme. This action on tryptophan peroxidase-oxidase is presumably due to the inhibition by 3-amino-1,2,4-triazole on one of the enzymes involved in porphyrin synthesis.

Liver Arginase, Histidase and Phenylalanine Transaminase Following Administration of their Respective Substrates.∗

Summary Rat liver arginase, histidase and phenylalanine (pyruvate) transaminase as well as rabbit liver histidase did not increase following injection of their respective amino acid substrates.

Serum-Vitamin-A Levels in Two Families with Tylosis

FTo. 3.-Hybridization of haemoglobins Beilinson and the present K (for details of technique see Raper, Gammack, Huehns, and Shooter, 1960). Hb Beilinson is an unchain abnormal variant, and, after dissociation with Hb K and recombination, electrophoresis on starch gel clearly shows an additional fraction due to the formation of Hb A and Hb Beilnson/K; these two haemoglobins migrate as one fraction (see text). Left-before; right after dissociation and recombination.