Flashbulb memories and posttraumatic stress reactions across the life span: age-related effects of the German occupation of Denmark during World War II.

A representative sample of older Danes were interviewed about experiences from the German occupation of Denmark in World War II. The number of participants with flashbulb memories for the German invasion (1940) and capitulation (1945) increased with participants' age at the time of the events up to age 8. Among participants under 8 years at the time of their most traumatic event, age at the time correlated positively with the current level of posttraumatic stress reactions and the vividness of stressful memories and their centrality to life story and identity. These findings were replicated in Study 2 for self-nominated stressful events sampled from the entire life span using a representative sample of Danes born after 1945. The results are discussed in relation to posttraumatic stress disorder and childhood amnesia.

Water exchange rates of water-soluble manganese(III) porphyrins of therapeutical potential.

The activation parameters and the rate constants of the water-exchange reactions of Mn(III)TE-2-PyP(5+) (meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin) as cationic, Mn(III)TnHex-2-PyP(5+) (meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin) as sterically shielded cationic, and Mn(III)TSPP(3-) (meso-tetrakis(4-sulfonatophenyl)porphyrin) as anionic manganese(iii) porphyrins were determined from the temperature dependence of (17)O NMR relaxation rates. The rate constants at 298 K were obtained as 4.12 x 10(6) s(-1), 5.73 x 10(6) s(-1), and 2.74 x 10(7) s(-1), respectively. On the basis of the determined entropies of activation, an interchange-dissociative mechanism (I(d)) was proposed for the cationic complexes (DeltaS(double dagger) = approximately 0 J mol(-1) K(-1)) whereas a limiting dissociative mechanism (D) was proposed for Mn(III)TSPP(3-) complex (DeltaS(double dagger) = +79 J mol(-1) K(-1)). The obtained water exchange rate of Mn(III)TSPP(3-) corresponded well to the previously assumed value used by Koenig et al. (S. H. Koenig, R. D. Brown and M. Spiller, Magn. Reson. Med., 1987, 4, 52-260) to simulate the (1)H NMRD curves, therefore the measured value supports the theory developed for explaining the anomalous relaxivity of Mn(III)TSPP(3-) complex. A magnitude of the obtained water-exchange rate constants further confirms the suggested inner sphere electron transfer mechanism for the reactions of the two positively charged Mn(iii) porphyrins with the various biologically important oxygen and nitrogen reactive species. Due to the high biological and clinical relevance of the reactions that occur at the metal site of the studied Mn(iii) porphyrins, the determination of water exchange rates advanced our insight into their efficacy and mechanism of action, and in turn should impact their further development for both diagnostic (imaging) and therapeutic purposes.

Acid-base and electrochemical properties of manganese meso(ortho- and meta-N-ethylpyridyl)porphyrins: potentiometric, spectrophotometric and spectroelectrochemical study of protolytic and redox equilibria.

The difference in electrostatics and reduction potentials between manganese ortho-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP) and manganese meta-tetrakis(N-ethylpyridinium-3-yl)porphyrin (MnTE-3-PyP) is a challenging topic, particularly because of the high likelihood for their clinical development. Hence, a detailed study of the protolytic and electrochemical speciation of Mn(II-IV)TE-2-PyP and Mn(II-IV)TE-3-PyP in a broad pH range has been performed using the combined spectrophotometric and potentiometric methods. The results reveal that in aqueous solutions within the pH range ∼2-13 the following species exist: (H(2)O)Mn(II)TE-m-PyP(4+), (HO)Mn(II)TE-m-PyP(3+), (H(2)O)(2)Mn(III)TE-m-PyP(5+), (HO)(H(2)O)Mn(III)TE-m-PyP(4+), (O)(H(2)O)Mn(III)TE-m-PyP(3+), (O)(H(2)O)Mn(IV)TE-m-PyP(4+) and (O)(HO)Mn(IV)TE-m-PyP(3+) (m = 2, 3). All the protolytic equilibrium constants that include the accessible species as well as the thermodynamic parameters for each particular protolytic equilibrium have been determined. The corresponding formal reduction potentials related to the reduction of the above species and the thermodynamic parameters describing the accessible reduction couples were calculated as well.