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The results of a 13 °C, 9 GHz electron-paramagnetic resonance (EPR) investigation of the sulfate salts of the species formed by the base hydrolyses of solutions containing Mn2+ and Al3+, in the molar concentration range 1≤Mn/(Al+Mn)≤10% is reported. The EPR spectra of the microcrystalline samples consisted of the superposition of two overlapping axial, hyperfine structure (hfs) central transition Mn2+ resonances with g=1.9994(2) D=6.93(3) mT, A=8.56(3) mT, A=8.49(2), P=0.4(1)×10-4 mT, and gn=0.7(1)×10-3, and an unresolved resonance due to exchange coupled Mn2+ ions. The results are consistent with the interpretation that the resolved axial symmetry hfs central transition spectrum arises from Mn2+ ions replacing aluminum in either the tetrahedral or octahedral sites of the tridecameric Keggin-like cation [AlO4Al12(OH)24H2O)12]7+, which is known to form when Al3+ solutions are hydrolyzed under these conditions. The unresolved, exchange coupled spectrum must arise when two or more Mn2+ ions substitute into the same cation. The ratio of the intensities of the axial and exchange coupled Mn2+ centers had a maximum near the stoichiometric molar concentration 7.69% [i.e., Mn/(Al+Mn)=1:13]. The temperature dependence of the EPR spectral intensity and total hfs splitting for the resolved hfs central transition spectrum revealed that a first-order isomorphous phase transition occurred at 120 °C. . [ABSTRACT FROM AUTHOR]

Comparative brain proteome analysis is a new strategy to discover proteins and therefore genes whose altered expression may underlie schizophrenia. This strategy does not require an a priori theory of the pathogenesis or the mode of inheritance of schizophrenia. Using proteome analysis we previously compared the hippocampal proteome, that is, those proteins expressed by the hippocampal genome, of seven schizophrenic individuals with the hippocampal proteome of seven control individuals, matched for age and post mortem delay. We found 18 proteins that were significantly altered in concentration in the schizophrenic hippocampus (P < 0.05), when compared to control tissue. One of these proteins was characterised, by N-terminal sequencing, as diazepam binding inhibitor whose gene maps to 6q12-q21. Here we characterise a further three of the 18 proteins as: manganese superoxide dismutase, 6q25.3, T-complex protein 1, 6q25.3-q26 and collapsin response mediator protein 2, 8p21. That three of these four characterised proteins should map to the long arm of the same chromosome is significant (P < 0.002) and suggests the importance of chromosome 6q in schizophrenia. These results indicate that antioxidant defence is altered in the schizophrenic hippocampus and suggest that segregation distortion, of schizophrenia susceptibility genes, may be a possible causative factor in the high incidence of schizophrenia. [ABSTRACT FROM AUTHOR]

The proteins expressed by a genome have been termed the proteome. Comparative proteome analysis of brain tissue offers a novel means to identify biologically significant gene products that underlie psychopathology. In this study we collected post mortem hippocampal tissue from the brains of seven schizophrenic, seven Alzheimer's disease (AD) and seven control individuals. Hippocampal proteomes were visualised by two-dimensional gel electrophoresis of homogenised tissue. A mean of 549 (s.d. 35) proteins were successfully matched between each disease group and the control group. In comparison with the control hippocampal proteome, eight proteins in the schizophrenic hippocampal proteome were found to be decreased and eight increased in concentration, whereas, in the AD hippocampal proteome, 35 proteins were decreased and 73 were increased in concentration (P < 0.05). One protein, which was decreased in concentration in both diseases, was characterised as diazepam binding inhibitor (DBI) by N-terminal sequence analysis. DBI can regulate the action of the GABA[sub A] receptor. Protein changes involved 6% of the assessed AD hippocampal proteome, whereas, in schizophrenia protein changes involved less than 1% of the assessed hippocampal proteome. We conclude that schizophrenia has a subtle neuropathological presentation and comparative proteome analysis is a viable means by which to investigate diseases of the brain at the molecular level. [ABSTRACT FROM AUTHOR]