Citations

A nuclear magnetic resonance imaging (MRI) method is presented for quantitatively mapping the physical response of a material to harmonic mechanical excitation. The resulting images allow calculation of regional mechanical properties. Measurements of shear modulus obtained with the MRI technique in gel materials correlate with independent measurements of static shear modulus. The results indicate that displacement patterns corresponding to cyclic displacements smaller than 200 nanometers can be measured. The findings suggest the feasibility of a medical imaging technique for delineating elasticity and other mechanical properties of tissue.

Human memory is a polygenic trait. We performed a genome-wide screen to identify memory-related gene variants. A genomic locus encoding the brain protein KIBRA was significantly associated with memory performance in three independent, cognitively normal cohorts from Switzerland and the United States. Gene expression studies showed that KIBRA was expressed in memory-related brain structures. Functional magnetic resonance imaging detected KIBRA allele–dependent differences in hippocampal activations during memory retrieval. Evidence from these experiments suggests a role for KIBRA in human memory.

Aggregating autologous platelets caused contraction of isolated rings of canine left circumflex arteries. The contractions were augmented after removal of the endothelium and were attenuated by serotonergic antagonists. During contraction caused by prostaglandin F 2α , aggregating platelets caused a transient increase in tension followed by a profound relaxation of arteries with endothelium, but caused only further contraction of arteries without endothelium. These observations demonstrate the importance of the vascular endothelium in opposing the constriction of coronary vessels caused by 5-hydroxytryptamine and other substances released from aggregating platelets.

Transitional cell carcinoma was induced in the bladders of male Fischer rats by 12 oral doses of the carcinogen N -butyl- N -(4-hydroxybutyl)nitrosamine. Feeding of 13-cis-retinoic acid after completion of carcinogen treatment diminished the number and severity of cancers and other proliferative lesions of the bladder.