Biochemical characterization of cystine lyase from broccoli (Brassica oleracea var. italica).

Cystine lyase is the enzyme responsible for off-aroma deterioration in fresh unblanched broccoli. In this research, cystine lyase purification from broccoli has been optimized. Only one protein peak with cystine lyase activity was found during purification. Broccoli cystine lyase was purified 100-fold to homogeneity. L-Cystine, L-cysteine-S-sulfate, L-djenkolic acid, and some S-alkyl-L-cysteines and their sulfoxides are substrates, but the enzyme had negligible activity with L-cystathionine. A K(m) value of 81.2 microM was found for L-cystine. Inhibition and K(i) determinations indicated that L-cysteine is a linear noncompetitive inhibitor with a K(i) of 5 mM and DL-homocysteine is a competitive inhibitor with a K(i) of 1.5 mM. The molecular weight of cystine lyase was determined to be 100 kDa by three methods, with two subunits of 48 kDa each and a carbohydrate content of 3%. Further characterization included cofactor quantification, the effects of temperature and pH on activity and stability, and amino acid composition.

A randomized double-blind clinical trial of two antivenoms in patients bitten by Bothrops atrox in Colombia. The Regional Group on Antivenom Therapy Research (REGATHER).

A randomized double-blind clinical trial in 39 patients envenomed by Bothrops atrox in Antioquia and Chocó, Colombia, was performed to compare the efficacy and safety of 2 equine-derived antivenoms prepared at Instituto Clodomiro Picado, University of Costa Rica. Twenty patients received a monovalent anti-B. atrox antivenom (group A) and 19 patients were treated with a polyvalent (Crotalinae) antivenom (group B). Both antivenoms were equally efficient in the neutralization of the most relevant signs of envenoming (haemorrhage and blood clotting time alteration). Fourteen patients (36%) presented early adverse reactions to antivenoms and no significant difference between the 2 groups was observed. Urticaria (18%) was the most frequent early adverse reaction and there was no life-threatening anaphylactic reaction. Based on clinical criteria and serum venom levels, estimated by an enzyme immunoassay, 15 patients were classified into 2 groups: mild and moderate/severe envenoming. With the antivenom doses used in this study (3, 6 and 9 vials for mild, moderate and severe envenoming, respectively), both antivenoms were equally efficient in clearing serum venom levels within the first hour of treatment, and the levels remained below the lower limit of venom detection for 24 h. Antivenom concentration in serum remained high for up to 24 h after antivenom infusion, suggesting that an excess of antibody in relation to circulating antigen had been administered.

[Algorithm management for detection of monoclonal gammopathies in serum. Experience of the Instituto Nacional de Cancerología in México]. / Manejo de un algoritmo para la detección de gamopatías monoclonales en suero. Experiencia del Instituto Nacional de Cancerología en México.

BACKGROUND: Most patients with multiple myeloma have an abnormal band in the gamma region of protein electrophoresis. AIM: To correlate the clinical diagnosis with patterns of protein electrophoresis. METHODS: Retrospective analysis of all protein electrophoresis or immunoglobulin quantification requested during 1992 and review of clinical charts of patients. RESULTS: During 1992, 553 protein electrophoresis were requested. Of these, 344 were repetitions and 209 came from patients seen for the first time. Among the latter, we found a monoclonal component in 40. Of these 40 patients, 35 had a multiple myeloma, one had a plasmocytoma and four a non-Hodgkin lymphoma. Fourteen patients with diagnosis of myeloma did not have a monoclonal component in protein electrophoresis. These figures resulted in a 71% sensitivity and 97% specificity for monoclonal components in the diagnosis of multiple myeloma. The monoclonal component of patients with myeloma was characterized as IgG in 29 (60%), IgA in 5 (10%) and IgM in one. CONCLUSIONS: A monoclonal component present in a protein electrophoresis has a high diagnostic accuracy for multiple myeloma.