The effect of hippocampal function, volume and connectivity on posterior cingulate cortex functioning during episodic memory fMRI in mild cognitive impairment

Objectives: Diminished function of the posterior cingulate cortex (PCC) is a typical finding in early Alzheimer’s disease (AD). It is hypothesized that in early stage AD, PCC functioning relates to or reflects hippocampal dysfunction or atrophy. The aim of this study was to examine the relationship between hippocampus function, volume and structural connectivity, and PCC activation during an episodic memory task-related fMRI study in mild cognitive impairment (MCI). Method: MCI patients (n = 27) underwent episodic memory task-related fMRI, 3D-T1w MRI, 2D T2-FLAIR MRI and diffusion tensor imaging. Stepwise linear regression analysis was performed to examine the relationship between PCC activation and hippocampal activation, hippocampal volume and diffusion measures within the cingulum along the hippocampus. Results: We found a significant relationship between PCC and hippocampus activation during successful episodic memory encoding and correct recognition in MCI patients. We found no relationship between the PCC and structural hippocampal predictors. Conclusions: Our results indicate a relationship between PCC and hippocampus activation during episodic memory engagement in MCI. This may suggest that during episodic memory, functional network deterioration is the most important predictor of PCC functioning in MCI. Key Points: • PCC functioning during episodic memory relates to hippocampal functioning in MCI. • PCC functioning during episodic memory does not relate to hippocampal structure in MCI. • Functional network changes are an important predictor of PCC functioning in MCI

Metallomacrocycles as anion receptors: combining hydrogen bonding and ion pair based hosts formed from Ag(I) salts and flexible bis- and tris-pyrimidine ligands

[eng] Two self-assembled hosts are formed from Ag(I) salts and bis-pyrimidyl ligands and X-ray characterized. Both are able to incorporate two anions into the structure combining hydrogen bonding and electrostatic interactions

New Chlorido(dimethyl sulfoxide)iridium(III) complexes with N(6)-substituted adenines - Kinetic versus thermodynamic N(9) coordinated adenine isomers

[eng] New chlorido(dimethyl sulfoxide)iridium(III) complexes with N6‐substituted adenine derivatives: [IrIIICl4(DMSO‐κS){H‐AdeCx-κN(7)}]·nH2O [x = 3, n = 3 for 1; x = 4, n = 0.5 and 3 for 2a and 2b, respectively; x = 5, n = 0 for 3; x = 10, n = 0.33 for 4] and [IrIIICl4(DMSO‐κS){H‐AdeCx-κN(9)}] [x = 3 for 5; x = 4 for 6, x = 5 for 7; x = 10 for 8] have been synthesized and characterized by spectroscopic techniques and by single‐crystal X‐ray diffraction studies (1, 2b and 5). In all cases, iridium shows octahedral geometry and is coordinated to four chlorido ligands and one S atom from dimethyl sulfoxide (DMSO‐κS). The coordination sphere of the metal is completed by the N6‐substituted adenine molecule. Two different coordination modes are observed: (i) the ligand is protonated at N(1) and coordinated through N(7) (complexes 1-4); (ii) the adenine is protonated at N(3) and coordinated through N(9) (complexes 5-8). The kinetic/thermodynamic mechanisms that yield the different coordination products have been studied by using DFT calculations. Electrophoretic mobility studies and atomic force microscopy (AFM) investigation of the interaction between complexes 1, 5, 8 and plasmid pBR322 DNA have been performed

New Chlorido(dimethyl sulfoxide)iridium(III) Complexes with N6‐Substituted Adenines - Kinetic N(7) versus Thermodynamic N(9) Coordinated Adenine Isomers

[eng] New chlorido(dimethyl sulfoxide)iridium(III) complexes with N6‐substituted adenine derivatives: [IrIIICl4(DMSO‐κS){H‐AdeCx-κN(7)}]·nH2O [x = 3, n = 3 for 1; x = 4, n = 0.5 and 3 for 2a and 2b, respectively; x = 5, n = 0 for 3; x = 10, n = 0.33 for 4] and [IrIIICl4(DMSO‐κS){H‐AdeCx-κN(9)}] [x = 3 for 5; x = 4 for 6, x = 5 for 7; x = 10 for 8] have been synthesized and characterized by spectroscopic techniques and by single‐crystal X‐ray diffraction studies (1, 2b and 5). In all cases, iridium shows octahedral geometry and is coordinated to four chlorido ligands and one S atom from dimethyl sulfoxide (DMSO‐κS). The coordination sphere of the metal is completed by the N6‐substituted adenine molecule. Two different coordination modes are observed: (i) the ligand is protonated at N(1) and coordinated through N(7) (complexes 1-4); (ii) the adenine is protonated at N(3) and coordinated through N(9) (complexes 5-8). The kinetic/thermodynamic mechanisms that yield the different coordination products have been studied by using DFT calculations. Electrophoretic mobility studies and atomic force microscopy (AFM) investigation of the interaction between complexes 1, 5, 8 and plasmid pBR322 DNA have been performed

New chlorido(dimethyl sulfoxide)iridium (III) complexes with N(6)-adenine substituted adenines- kinetic N(7) versus thermodynamic N(9) coordinated adenine isomers

[eng] New chlorido(dimethyl sulfoxide)iridium(III) complexes with N6‐substituted adenine derivatives: [IrIIICl4(DMSO‐κS){H‐AdeCx-κN(7)}]·nH2O [x = 3, n = 3 for 1; x = 4, n = 0.5 and 3 for 2a and 2b, respectively; x = 5, n = 0 for 3; x = 10, n = 0.33 for 4] and [IrIIICl4(DMSO‐κS){H‐AdeCx-κN(9)}] [x = 3 for 5; x = 4 for 6, x = 5 for 7; x = 10 for 8] have been synthesized and characterized by spectroscopic techniques and by single‐crystal X‐ray diffraction studies (1, 2b and 5). In all cases, iridium shows octahedral geometry and is coordinated to four chlorido ligands and one S atom from dimethyl sulfoxide (DMSO‐κS). The coordination sphere of the metal is completed by the N6‐substituted adenine molecule. Two different coordination modes are observed: (i) the ligand is protonated at N(1) and coordinated through N(7) (complexes 1-4); (ii) the adenine is protonated at N(3) and coordinated through N(9) (complexes 5-8). The kinetic/thermodynamic mechanisms that yield the different coordination products have been studied by using DFT calculations. Electrophoretic mobility studies and atomic force microscopy (AFM) investigation of the interaction between complexes 1, 5, 8 and plasmid pBR322 DNA have been performed