Accumulation of ammonia in body tissues most commonly occurs in hepatic failure. However, it may also result from a specific deficiency of an enzyme of the urea cycle (Fig., 1). Severe hyperammonaemia has been reported with deficiencies of carbamyl phosphate synthetase (Freeman et al., 1964) and ornithine transcarbamylase (Russell et al., 1962; Levin and Russell, 1967). Some increase in blood a...

Aberrant expression of argininosuccinate synthetase (ASS1, also known as ASS) has been found in cancer cells and is involved in the carcinogenesis of gastric cancer. The aim of the present study was to investigate the level of ASS expression in human gastric cancer and to determine the possible correlations between ASS expression and clinicopathological findings. Immunohistochemistry was perfor...

The omithine cycle [1], also called the urea cycle, is an enzyme system that converts ammonia into urea (for recent reviews, see [2-4]) (Figure 1). Ammonia, which is produced mainly by amino acid metabolism, is toxic to higher animals, and must be excreted or detoxified. Fish and amphibian larvae such as tadpoles excrete ammonia from the gills directly into the surrounding water. Mammalian fetu...

Recombinant plasmids with inserts complementary to the mRNA for carbamyl phosphate synthetase I were identified from a rat liver cDNA library by hybrid-selected mRNA translation. Four clones, the largest being 3100 base pairs, were identified for the rat liver enzyme. Using the rat liver cDNA as a probe, two homologous recombinant plasmids of approximately 1200 base pairs in length were isolate...

Accumulation of ammonia in body tissues most commonly occurs in hepatic failure. However, it may also result from a specific deficiency of an enzyme of the urea cycle (Fig., 1). Severe hyperammonaemia has been reported with deficiencies of carbamyl phosphate synthetase (Freeman et al., 1964) and ornithine transcarbamylase (Russell et al., 1962; Levin and Russell, 1967). Some increase in blood a...

Remarkable improvements in public health, nutrition, hygiene, and availability of medical services in the last 20 years have significantly reduced infant and childhood mortality in Thailand. Therefore, many rare and previously unidentified genetic disorders, which, in the past, usually led to the death of affected infants before a definitive diagnosis, have now been increasingly recognized. Rec...

Nonhepatic human cell variants resistant to the arginine analog, canavanine, express argininosuccinate synthetase (AS) mRNA at levels 200-fold higher than parental cells without amplification of AS gene sequences. In this report we show that this regulation occurs in the nucleus prior to polyadenylation of AS precursor RNA and occurs through a positive-acting mechanism operating in canavanine-r...

1. In the first experiment sheep taken from pasture were given a low-protein diet for six weeks in individual pens. Then, for 1 week, groups were given a supplement of lucerne chaff, safflower meal or lucerne chaff plus safflower meal. In the second experiment eighteen sheep maintained on lucerne chaff rather than pasture were then depleted of protein to a greater extent by feeding on a restric...

Endogenous nitric oxide synthase (eNOS) inhibitor asymmetric dimethylarginine (ADMA) is a cardiovascular risk factor. We tested the hypothesis that L-citrulline may ameliorate the endothelial function altered by ADMA in porcine coronary artery (PCA). Myograph study for vasorelaxation, electrochemical measurement for NO, RT-PCR, and Western blot analysis for expression of eNOS, argininosuccinate...

Citrullinemia type 1 was diagnosed by tandem mass spectrometry in a full term male neonate who presented with an acute catastrophic collapse on the 3rd day of life. Both parents were identified to be carriers for the exon 15 p Gly390Arg mutation in the argininosuccinate synthetase gene located at chromosome 9q34.1. Chorionic villus sampling and prenatal genetic testing in the subsequent pregnan...