  Hot subluminous stars can be spectroscopically classified as subdwarf B (sdB)
and O (sdO) stars. While the latter are predominantly hydrogen deficient, the
former are mostly helium deficient. The atmospheres of most sdOs are almost
devoid of hydrogen, whereas a small group of hot subdwarf stars of mixed H/He
composition exists, showing extreme metal abundance anomalies. Whether such
intermediate helium-rich (iHe) subdwarf stars provide an evolutionary link
between the dominant classes is an open question. The presence of strong Ge,
Sn, and Pb lines in the UV spectrum of HZ$\,$44 suggests a strong enrichment of
heavy elements in this iHe-sdO star and calls for a detailed quantitative
spectral analysis focusing on trans-iron elements. Non-LTE model atmospheres
calculated with TLUSTY are combined with high-quality optical, UV and FUV
spectra of HZ$\,$44 and its hotter sibling HD$\,$127493 to determine their
atmospheric parameters and metal abundance patterns. By collecting atomic data
from literature we succeeded to determine abundances of 29 metals in HZ$\,$44,
including the trans-iron elements Ga, Ge, As, Se, Zr, Sn, and Pb and provide
upper limits for 10 other metals. This makes it the best described hot subdwarf
in terms of chemical composition. For HD$\,$127493 the abundance of 15 metals,
including Ga, Ge, and Pb and upper limits for another 16 metals were derived.
Heavy elements turn out to be overabundant by one to four orders of magnitude
with respect to the Sun. Zr and Pb are among the most enriched elements. The C,
N, and O abundance for both stars can be explained by nucleosynthesis of
hydrogen burning in the CNO cycle along with their helium enrichment. On the
other hand, the heavy-element anomalies are unlikely to be caused by
nucleosynthesis. Instead diffusion processes are evoked with radiative
levitation overcoming gravitational settlement of the heavy elements.
