[Histiocytosis X: localized and disseminated forms. Apropos of 13 cases]

The authors present a study of 13 patients, between 7 months and 4 years of age diagnosed, of histiocytosis X, nine of them with a disseminated form and 4 with a localized form. The clinical and histopathologic types of presentation are analyzed, applying the usual scores of prognostic evaluation, with emphasis on the low mortality rate (one death), considering that there are several patients with bad prognostic scores. This is explained by the positive effect of chemotherapy used in these cases.

Biochemical parameters to assess cell differentiation of Bouvardia ternifolia Schlecht callus

Calli derived from leaves and radicles of B. ternifolia were grown on Murashige and Skoog (MS) basal medium, and the effects of different nitrogen sources on the rate of callus growth and on the enzymes related to nitrogen assimilation were studied. Ammonium alone did not support callus growth unless a Krebs-cycle intermediate was added to the medium. The activities of glutamine synthetase (EC 6.3.1.2), glutamate synthase (EC 1.4.7.1), and glutamate dehydrogenase (EC 1.4.1.2) were measured in homogenates of callus grown on media supplied with different nitrogen sources. The results indicate that leaf and root calli have similar levels of these enzymes when grown on MS medium (Murashige and Skoog 1962. Physiol. Plant. 15, 473-497). However, when the calli were supplied with glutamine as the sole nitrogen source, the activity of glutamate synthase increased in leaf callus but was almost completely inhibited in root callus. The results indicate that calli originated from different B. ternifolia tissues do not have the same biochemical dedifferentiated state.