Violacein cytotoxicity on human blood lymphocytes and effect on phosphatases.

Given the importance of protein phosphorylation in the context of cellular functions, abnormal protein phosphatase activity has been implicated in several diseases, including cancer. These critical roles of protein phosphatases qualify them as potential targets for the development of medicinal compounds that possess distinct modes of action such as violacein. In this work, studies with this natural indolic pigment at a concentration of 10.0 micromol L(-1) demonstrated a 20% activation of total protein phosphatase extracted from human lymphocytes. Although no alteration was observed on protein tyrosine phosphatase (CD45), 30% of inhibition was achieved in cytoplasmatic protein phosphatase activity after incubation with 10.0 micromol L(-1) violacein. Additionally, 5.0 micromol L(-1) of violacein inhibited by 50% the serum tartrate-resistant acid phosphatase activity. Violacein presented toxic effect on lymphocytes with IC50 values of 3 and 10 micromol L(-1) for protein content and protein phosphatase activity, respectively. These findings suggest an important role for protein phosphatases in the mechanisms controlling proliferation and cell death.

[Hematological serological valves, and organ weight in adult Sprague-Dawley rats]. / Valores hematológicos, serológicos y peso de órganos en la rata Sprague-Dawley adulta.

Sprague-Dawley rats are frequently used in experiments and their normal hematological, serologic and anatomical parameters are not easily available. The aim of this study was to measure these parameters in adult Sprague-Dawley rats. Twenty-four rats (12 males) whose weight ranged between 200 and 300 g, raised at the Instituto de Salud Pública in controlled environmental conditions and fed with pellets were studied. After a 24 h fast, animals were anesthetized with Droperidol and Ketamine, and after obtaining a cardiac blood sample, sacrificed by exsanguination. Most organs were withdrawn and weighed. Mean values for blood glucose, calcium, amylase, total proteins, cholesterol, AST, ALT, bilirubin, alkaline phosphatases, electrolytes and complete blood count were determined. Heart, lung, pancreas, kidney and testicle mean weight was also calculated. Male and female rats had significant differences in packed red cell volume, white blood cell count and hemoglobin.

Allosteric transition of erythrocyte alkaline phosphatase from Duchenne muscular dystrophy (DMD) patients and Duchenne muscular dystrophy carriers (Homo sapiens).

1. The kinetic properties of the p-nitrophenylphosphatase (EC 3.1.3.1) from erythrocytes was investigated in DMD-patients and DMD-carriers. 2. A different allosteric behaviour in the p-nitrophenylphosphatase from DMD-patients and DMD-carriers compared to controls is supported by the following findings: (a) values of n altered in F- inhibition of (K+)-activated p-nitrophenylphosphatase with Hill coefficients -1.5, -2.2 and -3.1; (b) heterotropic effect of increased concentration of Mg2+ on F- inhibition which is reverted by K+ in DMD-carriers and in control, but not in DMD-patients. 3. Evidence is presented showing that in DMD-patients and in DMD-carriers the interaction membrane-enzyme is different from the corresponding controls.