A study of urea-synthesizing enzymes in prenatal and postnatal human liver.

The urea-synthesizing enzymes of human liver tissues, namely, carbamylphosphate synthetase (CPS, EC 2.7.2.

Age-dependent variations of lysosomal enzymes in human liver.

The specific activities, the Km values, and the elution patterns on DEAE 52 and Sephadex G-150 columns of six lysosomal enzymes in human liver during development were studied. The levels of total beta-D-glucuronidase and N-acetyl-beta-D-glucosaminidase activities in childhood liver were higher than those in fetal liver. The Km values of beta-D-glucuronidase and beta-D-galactosidase in fetal liver were about ten times higher than those in childhood liver.

Neuraminidase activity in liver and brain from patients with I-cell disease.

The activity of neuraminidase in liver and brain from I-cell disease (Mucolipidosis II) was investigated. Neuraminidase activities using two substrates [alpha-L-N-acetylneuraminosyl(2 leads to 3)lactose and alpha-L-N-acetylneuraminosyl(2 leads to 6)lactose] were reduced in the supernatant and sedimentable fractions obtained in isotonic KCl. The activity of beta-D-galactosidase was also reduced in the liver; on the other hand, both neuraminidase fractions were normal, although beta-galactosidase activities were markedly reduced.

Identification of keratan sulfate in liver affected by Morquio syndrome.

Glycosaminoglycan content, composition and molecular weight were determined in liver obtained from a patient with Morquio syndrome (Mucopolysaccharidosis IV). There was about a four-fold increase in glycosaminoglycan content (as hexosamine) of the affected liver as compared to the control liver. The major glycosaminoglycan accumulated in the liver was keratan sulfate, which was not found in the control liver.

Sphingomyelinase activities in cultured skin fibroblasts from patients with Niemann-Pick Disease.

Sphingomyelinase activity in cultured skin fibroblasts from a fetus affected with infantile-type Niemann-Pick disease was 0.5% of control activity; the activities in cells from two patients with adult-type disease (Cases 2 and 3) were 5.0% and 59.

Dubin-Johnson syndrome in a neonate.

We described the clinical and biochemical findings in a 32 day-old boy with the Dubin-Johnson syndrome. Only two other patients diagnosed as having the Dubin-Johnson syndrome during neonatal period have been reported in the literature. The ratio of urinary coproporphyrin isomer I of our patient was 97% and that of his parents were carrier level, confirming that increased urinary excretion of coproporphyrin isomer I is of diagnostic value in neonates with the Dubin-Johnson syndrome.

Lysosomal acid hydrolases in established lymphoblastoid cell lines, transformed by Epstein-Barr virus, from patients with genetic lysosomal storage diseases.

Lysosomal acid hydrolases were determined in established lymphoblastoid cell lines, transformed in vitro by Epstein-Barr virus (EBV) from lymphocyte-rich cell populations isolated from the peripheral blood of patients with genetic lysosomal storage diseases--Hurler syndrome, Scheie syndrome, GM1-gangliosidosis type 1 and type 2, Tay-Sachs disease, and I-cell disease--and from obligate heterozygotes for these diseases. The respective enzyme activity was undectectable in lymphoblastoid cells from the patients, but not from controls. Obligate heterozygotes could not always be distinguished from controls in lymphoblastoid cells as well as in leukocytes.

Chronic Niemann-Pick disease with sphingomyelinase deficiency in two brothers with mental retardation.

Clinical, biochemical, and electron microscopic studies are presented in two brothers with Niemann-Pick disease. The clinical features include hepatosplenomegaly and mental retardation without any other neurological signs. Roentgenograms of the chest showed bilateral diffuse reticular infiltration.

alpha-L-Iduronidase activity in established lymphoblastoid cells from patients with Hurler and Scheie syndromes transformed by Epstein-Barr virus.

alpha-L-Iduronidase activity was determined in established lymphoblastoid cells, which were transformed in vitro by Epstein-Barr virus, of lymphocytes-rich cell populations isolated from peripheral blood of patients with Hurler and Scheie syndromes. alpha-L-Iduronidase activities in established lymphoblastoid cells from patients were undetectable, while activities of control subjects were clearly detected. These results suggest that established lymphoblastoid cells are useful for the enzymatic study of genetic mucopolysaccharidoses.

Clinical and biochemical studies on periodic hyperammonemia with hyperlysinemia and homocitrullinuria.

An 18-year-old mentally and physically retarded boy, suffering from episodes of anorexia, vomiting, coma and convulsion which have been severer with advance in age, had periodic hyperammonemia, hyperlysinemia and homocitrullinuria. Blood cell arginase activity of the patient on normal diet was markedly reduced after an oral load of L-lysine. The oral loading tests of L-lysine revealed hyperammonemia, hyperlysinemia, hyperargininemia, hypercitrullinemia and homocitrullinuria.