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Biomedical subjects

R Moratti

Publications and source records attributed to R Moratti.

At least 55 records · Page 3Linked to original sources
PubMed1969

Control of the citric acid cycle by glyoxylate. The mechanism of inhibition of oxoglutarate dehydrogenase, isocitrate dehydrogenase and aconitate hydratase.

1. The effects of glyoxylate on partially purified preparations of aconitate hydratase, isocitrate dehydrogenase and oxoglutarate dehydrogenase were compared with those of oxalomalate and hydroxyoxoglutarate (obtained by condensation of glyoxylate with oxaloacetate and pyruvate respectively). 2. Glyoxylate (1mm) did not affect aconitate hydratase and isocitrate dehydrogenase, whereas oxalomalate (1mm) inhibited the enzyme activities completely. 3. Glyoxylate (0.025mm) inhibited oxoglutarate dehydrogenase irreversibly, whereas the same concentrations of oxalomalate and hydroxyoxoglutarate were ineffective. This inhibitory effect was prevented if oxoglutarate, pyruvate or oxaloacetate was mixed with the enzyme before the glyoxylate. 4. Incubation of oxoglutarate dehydrogenase with radioactive glyoxylate produced radioactive carbon dioxide; radioactivity was also recovered in the portion of the enzyme identified with thiamin pyrophosphate. 5. The behaviour of glyoxylate in producing multiple inhibitions of the citric acid cycle, either by direct interaction with oxoglutarate dehydrogenase, or by means of its condensation compounds which inhibit aconitate hydratase and isocitrate dehydrogenase, is discussed.

Animals↗
PubMed1967

Control of the citric acid cycle by glyoxylate. Mechanism of the inhibition by oxalomalate and gamma-hydroxy-alpha-oxoglutarate.

1. Hydroxyoxoglutarate was obtained by three methods: decarboxylation of oxalomalic acid, and synthesis from glyoxylate and pyruvate by using either Mg(2+) or an enzyme from rat liver as catalysts. 2. The inhibitory effects of oxalomalate and hydroxyoxoglutarate upon aconitate hydratase, isocitrate dehydrogenase (NADP) and oxoglutarate dehydrogenase were investigated. 3. Oxalomalate at low concentrations (1mm) inhibited almost completely both aconitate hydratase and isocitrate dehydrogenase. Hydroxyoxoglutarate also inhibited these enzymes, but at concentrations approximately tenfold that of oxalomalate. 4. Oxalomalate and hydroxyoxoglutarate, at the higher concentrations, inhibited oxoglutarate dehydrogenase to approximately the same extent. 5. It is suggested that the ability of glyoxylate to control reaction rates in the tricarboxylic acid cycle must in some degree be due to its condensation with oxaloacetate and pyruvate to form enzyme inhibitors.

Chemical Phenomena↗
PubMedDate not supplied

Circulating CA 549 and other associated antigens in breast cancer patients.

The new marker CA 549 was determined in the serum of 258 breast cancer patients, classified according to TNM (148 at diagnosis and 110 at relapse), using a RIA method (cut-off: 10 U/ml). CEA, CA 15-3 and MCA were also evaluated. At diagnosis, CA 549 was more sensitive than the other markers, and cut-off values of 11 and 12 U/ml did not significantly reduce sensitivity. No significant correlation existed between the markers, except for CA 15-3 and CA 549 (r = 0.65). A new quantitative approach to the four markers was effected in the relapsed patients: an X value was calculated for each marker by dividing serum concentration by its cut-off. In these patients, grouped according to the area involved, marker sensitivities were similar except in locoregional relapse, where CA 549 and MCA were the most sensitive. From the data obtained, the more defined cut-off and the good specificity, it is suggested that CA 549 be routinely determined in the follow-up of the disease.

Antigens, Neoplasm↗
PubMedDate not supplied

Efficiency of composite laboratory tests in the diagnosis of liver malignancies.

The utility of the markers CEA, beta-HCG, CA-50, alpha-fetoprotein (APF), ferritin, alkaline phosphatase (AP), its isoenzyme liver-1 (APL1), gamma-glutamyltransferase (gGT), its fast migrating isoenzyme (gGT1) and 5'nucleotidase (5'N) in differentiating liver malignancies and benign involvement was evaluated in the sera of 85 patients with hepatocellular carcinoma (HCC), 157 with chronic liver disease (CLD) and 91 with liver metastases (LM) derived from different tumors. The mean concentrations of all the parameters except CEA and GGT1 were significantly different in HCC and CLD, but a broad overlap existed in the two groups, so different cut-offs were considered to assess the positive and negative predictive values and test efficiency (Eff). The best results were observed considering AFP greater than 100 IU/m (Eff0.86), ferritin greater than 800 ng/ml (Eff0.69), CA-50 greater than 100 U/ml (Eff 0.63), beta-HCG greater than 10 mU/ml (Eff 0.61), AP greater than 300 IU/ml (Eff 0.66), the presence of APL1 (Eff 0.78), 5'N greater than 25 mU/ml (Eff 0.70), gGT greater than 100 mIU/ml (Eff 0.63). Among HCC patients 17% did not secrete AFP; in 26% the protein was less than 100 IU/ml and in 36% less than 400 IU/ml. Apart from AFP the most effective marker was APL1. At the above cut-offs more than three parameters were simultaneously positive in 71% of HCC and 9.9% of CLD. CEA, CA50, AFP were the only parameters that distinguished the HCC from the LM group; in the latter, APL1 was also a very sensitive marker (87%) for neoplastic involvement of the liver.

Adult↗