[en] Intrathecal ₁₉₈Au colloid and methotrexate were administered to 27 children (between 1972 and 1981) with non-lymphatic leukaemia, 21 with non-Hodgkin lymphoma and two with Ewing's sarcoma to prevent CNS involvement. In one boy with non-lymphatic leukaemia a stable remission after a three-year period of cytostatic treatment ended with isolated CNS involvement. No isolated CNS recurrence occurred in children with non-Hodgkin lymphoma receiving regular radiogold administration. Combined iris and CNS recurrence occurred in one child with non-Hodkin lymphoma. Eleven of 21 children with non-Hodgkin lymphoma have been in complete initial remission for 4-39 months without cytostatic treatment. Late cerebral complications have not been observed after ₁₉₈Au colloid and methotrexate. (orig.)

[en] 26 children suffering from acute leukemia and non-Hodgkin lymphoma (group 1) received intrathecal Au-198-colloid injections as a prophylactic measure against central nervous system (CNS) relapses. No primary CNS relapses were observed in the period from 1 Sep. 1974 to 31 Oct. 1978. Two children were taken ill at the same time with meningosis leucaemica in the first and second relapse, respectively. Four children (group 2) were treated with Au-198-colloid after overcoming a meningosis leucaemica. It was not possible to prevent another CNS relapse in all four patients of this group. Clinical status, liquor tests and EEG examinations carried out after the therapy showed good tolerance of the gold colloid. (author)

[en] We exploit ionization-parameter mapping (IPM) as a powerful tool to measure the optical depth of star-forming H II regions. Our simulations using the photoionization code CLOUDY and our new, SURFBRIGHT surface-brightness simulator demonstrate that this technique can directly diagnose most density-bounded, optically thin nebulae using spatially resolved emission-line data. We apply this method to the Large and Small Magellanic Clouds (LMC and SMC), using the data from the Magellanic Clouds Emission Line Survey. We generate new H II region catalogs based on photoionization criteria set by the observed ionization structure in the [S II]/[O III] ratio and Hα surface brightness. The luminosity functions from these catalogs generally agree with those from Hα-only surveys. We then use IPM to crudely classify all the nebulae into optically thick versus optically thin categories, yielding fundamental new insights into Lyman-continuum (LyC) radiation transfer. We find that in both galaxies, the frequency of optically thin objects correlates with Hα luminosity, and that the numbers of these objects dominate above log L/(erg s^–1) ≥ 37.0. The frequencies of optically thin objects are 40% and 33% in the LMC and SMC, respectively. Similarly, the frequency of optically thick regions correlates with H I column density, with optically thin objects dominating at the lowest N(H I). The integrated escape luminosity of ionizing radiation is dominated by the largest regions and corresponds to luminosity-weighted, ionizing escape fractions from the H II region population of ≥0.42 and ≥0.40 in the LMC and SMC, respectively. These values correspond to global galactic escape fractions of 4% and 11%, respectively. This is sufficient to power the ionization rate of the observed diffuse ionized gas in both galaxies. Since our optical depth estimates tend to be underestimates, and also omit the contribution from field stars without nebulae, our results suggest the possibility of significant galactic escape fractions of LyC radiation.