  In this contribution I summarize and discuss the results of the bulk
thermodynamic characteristics, meson and nucleon structure in hot matter
obtained in the framework of a chiral quark-meson theory. A hybrid NJL model is
used in which a Dirac sea of quarks is combined with a Fermi sea of quarks or
of nucleons. In the model mesons are described as collective $\bar qq$
excitations and the nucleon appears as a baryon-number-one soliton of $N_c$
valence quarks coupled to both Dirac and Fermi sea. According to the model at
some critical density and/or temperature phase transitions from nucleons to
quarks as well as from Goldstone to Wigner phase are expected. At finite
density the chiral order parameter and the constituent quark mass have a
non-monotonic temperature dependence-at temperatures not close to the critical
one they are less affected than in cold matter. The quark matter is rather soft
against thermal fluctuations and the corresponding chiral phase transition is
smooth. The nucleon matter is much stiffer and the phase transition is very
sharp. In the case of quark matter a first-order transition is suggested at low
temperatures ($T<80$ MeV) which changes to a second-order one at higher
temperatures. In contrast to the quark matter in the case of nucleon matter the
thermodynamic variables show large discontinuities which is a clear indication
for a first-order phase transition. In hot medium at intermediate temperature
the nucleon soliton is more bound and less swelled than in the case of cold
matter. At some critical temperature, which for nucleon matter coincides with
the critical temperature for the phase transition, no more a localized solution
is found. According to this model scenario one should expect a first-order
phase transition from nucleon to quark matter.
