Biomedical subjects
Publications and source records attributed to J Pipek.
Coarse grained Langevin-type effective field equations may provide some guidance for the analysis of mesoscopic or microscopic molecular systems exhibiting fluctuations, or for systems of hundreds to thousands of atomic or subatomic particles produced in atomic or high-energy nuclear collisions. Suggestions for consistent realization of random fluctuations in discretized fluid dynamics will be presented.
Arginine is an acid possessing a guanidine side group which is protonated at all biological pHs, R-NH-C(=NH2+)-NH2. We have performed computations on the neutral species by the ab initio method using MINI and 6-31G(d) basis sets. Geometry optimization at the HF SCF level has also been carried out using the 6-31 G(d) basis set. We investigated the addition of formaldehyde to both the NH2- and H-N=C sites of the guanidine side group. The calculated exothermicities of the reactions with formaldehyde were found different for the above structures. We are planning to determine the energy barriers for these reactions in the near future.
The investigations proved that D-glucose (as reducing sugar) can easily be activated in a ternary system (L-lysine: D-glucose: H2O2) similarly to formaldehyde at 20 degrees C, in pH = 7.4 forming chemiluminescence (CL) and singlet oxygen. The kinetic investigation showed that: CL lasted many hours (permanent emission) and had no bell-shaped curve differently from other aldehydes e.g. formaldehyde. The reason of the effect is that D-glucose exists mainly in ring form in water solution (Haworth ring form) and the open form (the aldehyde group) is slowly liberated during the excited reaction. These excited reactions may be important in human organism, because D-glucose and lysyl residues of proteins occur permanently in human body and endogenous formaldehyde and H2O2 may be liberated there, too.
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