Collagen-Specific Molecular Magnetic Resonance Imaging of Prostate Cancer

Constant interactions between tumor cells and the extracellular matrix (ECM) influence the progression of prostate cancer (PCa). One of the key components of the ECM are collagen fibers, since they are responsible for the tissue stiffness, growth, adhesion, proliferation, migration, invasion/metastasis, cell signaling, and immune recruitment of tumor cells. To explore this molecular marker in the content of PCa, we investigated two different tumor volumes (500 mm³ and 1000 mm³) of a xenograft mouse model of PCa with molecular magnetic resonance imaging (MRI) using a collagen-specific probe. For in vivo MRI evaluation, T1-weighted sequences before and after probe administration were analyzed. No significant signal difference between the two tumor volumes could be found. However, we detected a significant difference between the signal intensity of the peripheral tumor area and the central area of the tumor, at both 500 mm³ (p < 0.01, n = 16) and at 1000 mm³ (p < 0.01, n = 16). The results of our histologic analyses confirmed the in vivo studies: There was no significant difference in the amount of collagen between the two tumor volumes (p > 0.05), but within the tumor, higher collagen expression was observed in the peripheral area compared with the central area of the tumor. Laser ablation with inductively coupled plasma mass spectrometry further confirmed these results. The 1000 mm³ tumors contained 2.8 ± 1.0% collagen and the 500 mm³ tumors contained 3.2 ± 1.2% (n = 16). There was a strong correlation between the in vivo MRI data and the ex vivo histological data (y = −0.068x + 1.1; R² = 0.74) (n = 16). The results of elemental analysis by inductively coupled plasma mass spectrometry supported the MRI data (y = 3.82x + 0.56; R² = 0.79; n = 7). MRI with the collagen-specific probe in PCa enables differentiation between different tumor areas. This may help to differentiate tumor from healthy tissue, potentially identifying tumor areas with a specific tumor biology.     

Bücherschau

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Butter, Speisefette und ?le

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Über die Si?N-Bindung. XXXIX [1]. Kinetische Untersuchungen zur spontanen Hydrolyse,Alkoholyse und Phenolyse von Aminosilanen

Silicon-Nitrogen Bonds. XXXIX. Kinetic Studies on the Spontaneous Hydrolysis, Alcoholysis, and Phenolysis of Silylamines It could be shown by polarimetric and DC-metric methods that hydrolysis, alcoholysis, and phenolysis of silylamines are of second order and lead to equilibria. The rate of equilibrium establishment is determined by the position of a preceding protonation equilibrium and by steric effects. The position of the equilibria depends on inductive and steric effects. The enthalpy of activation for the ethanolysis of Me₃SiNHPh was determined to 27,2 kJ/mol and the entropy of activation to –231 J/K · mol. The mechanism of the reactions is given.