Retroperitoneal cystic metastasis from a small clear cell renal carcinoma

A 39-year-old housewife was referred to our hospital for the treatment of a small renal tumor. A 25 x 35 mm cystic mass that had been detected by computerized tomography scan just caudal to the renal hilus proved to be a metastasis from the renal carcinoma of clear cell type. The pathogenesis may have been due to tumor cells obstructing a lymphatic vessel draining the kidney. Cystic metastasis from renal cell carcinoma is very rare and this appears to be the second published case in the world.     

Functional roles of endogenous d-serine in the chronic pain-induced plasticity of NMDAR-mediated synaptic transmission in the central amygdala of mice

The amygdala is implicated in chronic pain-induced emotional changes. Chronic pain induces plastic changes of the N-methyl-d-aspartate receptor (NMDAR) functions in the brain including the amygdala. d-Serine is synthesized endogenously by serine racemase and modulates NMDAR-mediated synaptic transmission as a coagonist of glycine binding site. To clarify the functional roles of endogenous d-serine in chronic pain-induced plasticity of NMDAR mediated synaptic transmission, we investigated the NMDAR-mediated excitatory synaptic current (EPSC) of neurons in the latero-capsular division of the central amygdala (CeLC) using brain slices from serine racemase knockout (SR-KO) mice with chronic pain induced by monoarthritis. The decay time of NMDAR-mediated EPSC was significantly elongated by monoarthritis in wild type (WT) mice, but not in SR-KO mice. The d-serine application-induced increase of NMDAR-mediated EPSC was significantly facilitated by monoarthritis in WT mice, but not in SR-KO mice. These results suggest that endogenous d-serine facilitates chronic pain-induced plastic changes of NMDAR mediated synaptic transmission in CeLC.     

Decreased perfusion of the bilateral thalami in patients with chronic pain detected by Tc-99m-ECD SPECT with statistical parametric mapping

The purpose of this study was to examine whether the Tc-99m-ECD SPECT can detect any difference between the brain perfusion in patients with chronic pain and normal controls by means of the Statistical Parametric Mapping (SPM96). The subjects were twelve patients with chronic pain (CP group) and twelve normal controls (NC group). After informed consent was obtained, 720 MBq of Tc-99m-ECD was intravenously injected as a bolus. The SPECT data were acquired once for 20 mins from 5 mins after i.v. injection of Tc-99m-ECD, with a triple-head rotating gamma camera. The SPECT data were transformed into a standard stereotactic space, and group comparisons between CP and NC groups were performed on a voxel-by-voxel basis. The subset of voxels exceeding a threshold of p < 0.001 in omnibus comparisons and remaining significant after correction for multiple comparison (p < 0.05) was displayed as a volume image rendered in three orthogonal projections. There was a significant decrease in perfusion in the bilateral thalami in the CP group, suggesting that perfusion in the thalamus generally decreases in patients with chronic pain. Tc-99m-ECD SPECT with SPM96 may be useful for studies of the mechanisms of chronic pain.     

An Efficient Local Molecular Dynamics Polymerization Simulation Combined with an Ab Initio MO Method

A new local ab initio molecular dynamics method, namely elongation molecular dynamics (ELG-MD) is proposed for highly efficient simulations of aperiodic polymer systems. ELG-MD combines the elongation method (ELG) with the Gear predictor corrector (GPC) algorithm of molecular dynamics simulation. In this method, the local gradients acting on the atom’s nucleus in the active region are calculated by the ELG method while the equations of the nucleus’s motion are solved by the GPC algorithm. In this work, the first application of this ELG-MD method is described to investigate the stable conformation of polyglycine with surrounding water molecules. The water effects on the structure of polyglycine are examined. The ELG-MD simulations show that the formation of the polyglycine helix is strongly induced by the hydrogen bonds observed in two types of H-bond rings.