Effect of NGF on in vitro preformed microtubules. Evidence for a protective action against vinblastine

The nerve growth factor protein (NGF) induces organization of in vitro preformed microtubules (MTs) to form multiple arrays. These complexes, in cross-section, appear to be formed by clusters of single tubules in parallel in close contact with center distance similar to the diameter of a microtubule. In the absence of NGF, on the contrary, microtubules are far apart from each other. Addition of vinblastine to NGF-MT complexes does not result in the usual reorganization of microtubules into paracrystalline arrays, noticeable when the growth factor is not present. The vinblastine treated NGF-MT complexes have several round-shaped elements along the tubules and at their endings which, at higher magnification, appear to be formed by closely packed, ring-like structures. These 'boutons' are postulated to represent the point of resistance to the depolymerizing action of the vinca alkaloid. These findings are discussed in relation to a similar antagonistic effect observed in vivo between NGF and vinblastine and to the possible involvement of microtubules in the mechanism of action of the growth factor.

[Complete polygraphic examination using the Diamont and Killip calculations in the functional evaluation of the heart patient]

Recently discharged infarct patients were examined to assess their ability to rehabilitate. This led to the elaboration of a classification based on polygraphic parameters, rather than the history and clinical record, coupled with comparison with the ideal values given for such subjects by the formula of Diamont and Killip.

[Prevention of arrhythmias during heart catheterization]

The utility of using beta blocking drugs, specifically Pindolol, as a prophylaxis for arrhythmia during cardiac microcatheterism according to Grandjean's technique has been observed. The drug is even more useful when it is considered that it does not affect dp/dt value.

Thyroglobulin biosynthesis in "cold" and "hot" nodules in the human thyroid gland

Studies on "cold" and "hot" nodules from human thyroid gland have been carried out to investigate thyroglobulin biosynthesis and to correlate carbohydrates incorporation and thyroid hormone formation in thyroglobulin. The aim of the investigation was to ascertain the role of carbohydrates of the protein molecule in its migration to the iodinating site of the cell. Thyroid slices from two cases with "cold" and two with "hot" nodules were incubated for 30 to 120 min with [3H]leucine, [3H]carbohydrates (ManNAc, Gal, Man, GlcNAc, GalNAc) and 125I. Soluble and particulate iodoproteins, solubilized by digitonin, were identified by density gradient centrifugation and immunoprecipitation; following hydrolysis carbohydrates and iodothyronines were identified by paper chromatography and chemically determined. While the rate of leucine incorporation into TG increased with time in both "cold" and "hot" nodules, the "cold" nodule, with respect to the "hot" tissue, showed: much lower efficiency incorporating carbohydrates and iodine into TG; lower thyroid/medium ratio of radioiodine; less total soluble protein and soluble TG; more particulate protein and solubilized TG; 1/3 of the carbohydrate and iodine chemical content; only minute amounts of labeled iodothyronines in TG compared to normal levels in "hot" tissue. The formation of thyroid hormone, in enzymatically iodinated TG, and the iodinating activity of the 105,000 X g pellet, incubated with low iodine TG, were similar in both "cold" and "hot" tissues. These results demonstrate that the "cold" nodule is able to synthesize thyroglobulin but the protein is defective in its carbohydrate content. The deficient iodine transport into "cold" tissue and impaired hormonal synthesis are confirmed. The incomplete incorporation of carbohydrates into thyroglobulin in the "cold" nodule could be important for the maturation and migration of the molecule to the iodinating site of the cell