Expression and localization of cysteine dioxygenase mRNA in the liver, lung, and kidney of the rat.

The expressions of cysteine dioxygenase (CDO) gene in the liver, lung, skeletal muscle, and kidney were studied by in situ hybridization with a cDNA probe from rat liver CDO under normal conditions. Significant expression of the CDO gene was detected in the liver, lung, and kidney, but not skeletal muscle. In the liver, the signal was confined to the cytoplasm of the hepatocytes. Furthermore, the signal was stronger in the periportal than that in the perivenous areas. In the lung, an intensive signal was found in the bronchiolar epithelium. As to the kidney, an intensive signal was observed in the distal convoluted tubules, while no signal was found in the proximal convultions.

Technetium-99m (V)-dimercaptosuccinic acid: normal accumulation in the breasts.

Technetium-99m (V)-dimercaptosuccinic acid (DMSA) is a tumour-imaging agent which has been used to evaluate medullary thyroid cancer and soft tissue tumours. Physiological uptake has been demonstrated in the kidneys, nasal mucosa and blood pool. In addition to positive accumulation in these sites, uptake in the breasts has been noted. The purpose of this retrospective study was to evaluate the accumulation of 99mTc (V)-DMSA in the normal breasts of 83 patients. There was no accumulation in male breasts. On the other hand, 24 of 51 female patients showed bilateral symmetrical accumulation in the breasts. Positive uptake was seen in 16 of 23 patients (70%) between 15 and 50 years old, but in only 7 of 25 (28%) above 50 years old. One out of three patients (33%) under 15 years old showed positive breast uptake. In conclusion, the female breasts should be included in the description of a pattern of normal biodistribution of 99mTc (V)-DMSA.

Structural organization and tissue-specific expression of the gene encoding rat cysteine dioxygenase.

Cysteine dioxygenase (CDO) is a key enzyme involved in the metabolism of L-cysteine. Genomic clones containing the 5'-flanking sequence of the rat CDO gene were isolated and characterized. The CDO gene spanned about 15 kb, and comprised 5 exons. All boundaries between the exons and introns matched the GT/AG rule. The major transcription start point (tsp) was A at 213 bp upstream from the ATG codon. The 5'-flanking region contained a TATA-box-like sequence and putative cis-acting regulatory elements. The 3' end of CDO was polyadenylated at several sites. Northern blots of RNA from rat tissues revealed the highest CDO mRNA level in the liver. Significant levels were observed in the kidney, lung and brain, implying tissue-specific differences in CDO promoter function.

Simultaneous determination of cystathionine and NAc-cystathionine using liquid chromatography atmospheric pressure chemical ionization mass spectrometry.

A method for simultaneous determination of cystathionine and NAc-cystathionine in biological samples has been developed by using column liquid chromatography-mass spectrometry. The concentrations of cystathionine and NAc-cystathionine in urine, several tissues, and serum of propargylglycine-treated rats with experimental cystathioninuria were determined by scanning the [M + H]+ ions of each compound. The recoveries of authentic compounds were 95.69 +/- 4.44% (n = 10) for cystathionine and 91.59 +/- 5.26% (n = 10) for NAc-cystathionine after ion-exchange resin treatment. The contents of cystathionine and NAc-cystathionine in the urine of a patient with cystathioninuria were also measured. The results coincided well with those obtained using an amino acid analyzer.