The distribution of parenchyma, follicles, and lymphocyte subsets in thymus of patients with myasthenia gravis, with special reference to remission after thymectomy

ObjectiveWe sought to examine the distribution of parenchyma, follicles, and lymphocyte subsets in the thymus of patients with myasthenia gravis and to identify determinants of remission after thymectomy.MethodsSixty patients with myasthenia gravis who underwent thymectomy were examined. The thymus was divided into upper, middle, and lower parts. The upper part was defined as the superior horn, the lower part as the inferior horn, and the middle part as tissue located between the 2 horns. The percentage of parenchyma was measured morphometrically. The degree of follicular hyperplasia was classified into 5 grades. The densities of CD3+, CD4+, and CD8+ lymphocytes were classified into 5 grades. The remission of myasthenia gravis after thymectomy was examined with those variables in each part of the thymus.ResultsThe middle part had the highest percentage of parenchyma, the highest grade of follicular hyperplasia, and the highest density of CD3+, CD4+, and CD8+ lymphocytes among the 3 parts (P < .001-.05). The grades of follicular hyperplasia in the middle and lower parts were significantly higher in patients with improvement of myasthenia gravis than in those without (P < .05). The densities of CD3+, CD4+, and CD8+ lymphocytes in the cortex of the middle part were significantly higher in patients with improvement than in those without improvement (P < .01-.05).ConclusionsThe thymus has a heterogeneous distribution of parenchyma, follicles, and lymphocyte subsets. The middle part had the largest parenchyma, the highest grade of follicular hyperplasia, and the highest densities of CD3+, CD4+, and CD8+ lymphocytes among the 3 parts of the thymus. The grade of follicular hyperplasia and the density of these lymphocyte subsets are predictive of improvement in myasthenia gravis after thymectomy

Effect of the blend ratio of cyclic and linear polyethylene blends on isothermal crystallization in the quiescent state

The role of entanglements that form between cyclic and linear polymers in crystallization is of particular interest, but it is not fully understood. We investigated the crystallization behaviors of blends of cyclic polyethylene (C-PE) and linear polyethylene (L-PE) in a quiescent state to elucidate the role of this novel entanglement in crystallization. The samples were prepared by mixing the prepared C-PE and L-PE specimens at L-PE weight fraction (ΦL-PE) values of 0–100 wt%, with the weight average molecular weights of C-PE and L-PE being 175 × 103 and 154 × 103, respectively. The isothermal crystallization behaviors were analyzed through polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The morphology observed through POM was similar to that of ΦL-PE. From the time evolution of the heat flow measured via DSC, we obtained the half-crystallization time (t1/2) values as functions of ΦL-PE at different degrees of supercooling (ΔT). The 1/t1/2 values of the C-PE and L-PE homopolymers were approximately the same at ΔT = 25.5 and 26.5 K. At a larger ΔT value, the 1/t1/2 value of C-PE was significantly larger than that of L-PE. In contrast, 1/t1/2 reached a minimum value at ΦL-PE = 30–40 wt%, irrespective of ΔT. As the entanglement density increased with increasing ΦL-PE, the crystallization rate was expected to decrease monotonically. By considering the experimental relationship between 1/t1/2 and ΦL-PE, we speculated that the suppression of crystallization in the blended system was caused by a novel entanglement formed by the penetration of the L-PE chain into the C-PE chain

Protective effects of cold spinoplegia with fasudil against ischemic spinal cord injury in rabbits

ObjectiveParaplegia remains a serious complication after surgical repair of thoracoabdominal aortic aneurysms. The aim of this study was to evaluate the neuroprotective efficacy of fasudil, a Rho kinase (ROCK) inhibitor, by reducing the number of infiltrating cells in the ventral horn and increasing the induction of eNOS against ischemic spinal cord injury in rabbits.MethodsEighteen Japanese white rabbits were divided into three groups: saline (group 1, n = 7, 4°C) and fasudil (group 2, n = 6, 4°C) were immediately infused into the isolated segmental lumbar arteries over 30 seconds after aortic clamping. Group 3 (n = 5) was the sham-operated group. Hind limb function was evaluated 4 and 8 hours, and 1 and 2 days after 15 minutes of transient ischemia. Cell damage was analyzed by hematoxylin and eosin staining and temporal profiles of endothelial nitric oxide synthase immunoreactivity were performed. The number of intact motor neuron cells and infiltrating cells in the ventral horn were compared.ResultsTwo days after reperfusion, group 2 and group 3 showed better neurologic function, a greater number of intact motor neuron cells, and a smaller number of infiltrating cells in the ventral horn than group 1. The induction of endothelial nitric oxide synthase (eNOS) was prolonged up to 2 days after reperfusion in group 2.ConclusionThese results indicate that fasudil has neuroprotective effects against ischemic spinal cord injury in rabbits by reducing the number of infiltrating cells in the ventral horn and prolonging the expression of eNOS.Clinical RelevanceParaplegia or paralysis caused by spinal cord ischemia remains a devastating and unpredictable complication after descending and thoracoabdominal aortic surgery. This study has revealed that fasudil has a neuroprotective effect against ischemic spinal cord injury in rabbits. Inhibition of the Rho/Rho kinase pathway by fasudil reduces the number of infiltrating cells in the ventral horn and prolongs the expression of eNOS. In the near future, Rho kinase may be an important therapeutic target for paraplegia induced by spinal cord ischemia

Novel Charge Ordering in the Trimer Iridium Oxide BaIrO3

We have prepared polycrystalline samples of the trimer Ir oxide BaIrO3 with face-shared Ir3O12 trimers, and have investigated the origin of the phase transition at 182 K by measuring resistivity, thermopower, magnetization and synchrotron x-ray diffraction. We propose a possible electronic model and transition mechanism, starting from a localized electron picture on the basis of the Rietveld refinement. Within this model, BaIrO3 can be basically regarded as a Mott insulator, when the Ir3O12 trimer is identified to one pseudo-atom or one lattice site. The transition can be viewed as a transition from the Mott insulator phase to a kind of charge ordered insulator phase.Comment: 8 pages 5 figures, Crystals (in press